Note: Descriptions are shown in the official language in which they were submitted.
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METHODS AND APPARATUS FOR HOLDING AND POSITIONING
SEMICONDUCTOR WORKPIECES DURING ELECTROPOLISHING
AND/OR ELECTROPLATING OF THE WORKPIECES
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention generally relates to methods and apparatus for holding
and positioning semiconductor workpieces during processing of the workpieces.
More particularly, the present invention relates to methods and apparatus for
holding
and positioning semiconductor workpieces during electroplating and/or
electropolishing of semiconductor workpieces.
2. Description of the Related Art
In general, semiconductor devices are manufactured or fabricated on disks of
semiconducting materials called wafers or slices. More particularly, wafers
are
1 S initially sliced from a silicon ingot. The wafers then undergo multiple
masking,
etching, and deposition processes to form the electronic circuitry of
semiconductor
devices.
During the past decades, the semiconductor industry has increased the power
of semiconductor devices in accordance with Moore's law, which predicts that
the
power of semiconductor devices will double every 18 months. This increase in
the
power of semiconductor devices has been achieved in part by decreasing the
feature
size (i.e., the smallest dimension present on a device) of these semiconductor
devices.
In fact, the feature size of semiconductor devices has quickly gone from 0.35
microns
to 0.25 microns, and now to 0.18 microns. Undoubtedly, this trend toward
smaller
semiconductor devices is likely to proceed well beyond the sub-0.18 micron
stage.
However, one potential limiting factor to developing more powerful
semiconductor devices is the increasing signal delays at the interconnections
(the lines
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of conductors, which connect elements of a single semiconductor device and/or
connect any number of semiconductor devices together). As the feature size of
semiconductor devices has decreased, the density of interconnections on the
devices
has increased. However, the closer proximity of interconnections increases the
line-
s to-line capacitance of the interconnections, which results in greater signal
delay at the
interconnections. In general, interconnection delays have been found to
increase with
the square of the reduction in feature size. In contrast, gate delays (i.e.,
delay at the
gates or mesas of semiconductor devices) have been found to increase linearly
with
the reduction in feature size.
One conventional approach to compensate for this increase in interconnection
delay has been to add more layers of metal. However, this approach has the
disadvantage of increasing production costs associated with forming the
additional
layers of metal. Furthermore, these additional layers of metal generate
additional
heat, which can be adverse to both chip performance and reliability.
Consequently, the semiconductor industry has started to use copper rather than
aluminum to form the metal interconnections. One advantage of copper is that
it has
greater conductivity than aluminum. Also, copper is less resistant to
electromigration
(meaning that a line formed from copper will have less tendency to thin under
current
load) than aluminum.
However, before copper can be widely used by the semiconductor industry,
new processing techniques are required. More particularly, a copper layer may
be
formed on a wafer using an electroplating process and/or etched using an
electropolishing process. In general, in an electroplating and/or an
electropolishing
process, the wafer is held within an electrolyte solution and an electric
charge is then
applied to the wafer. Thus, a wafer chuck is needed for holding the wafer and
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applying the electric charge to the wafer during the electroplating and/or
electropolishing process.
SUMMARY OF THE INVENTION
In an exemplary embodiment of the present invention, a wafer chuck assembly
for holding a wafer during electroplating and/or electropolishing of the wafer
includes
a wafer chuck for receiving the wafer. The wafer chuck assembly also includes
an
actuator assembly for moving the wafer chuck between a first and a second
position.
When in the first position, the wafer chuck is opened. When in the first
position, the
wafer chuck is closed.
DESCRIPTION OF THE DRAWING FIGURES
The subject matter of the present invention is particularly pointed out and
distinctly claimed in the concluding portion of the specification. The present
invention, however, both as to organization and method of operation, may best
be
understood by reference to the following description taken in conjunction with
the
claims and the accompanying drawing figures, in which like parts may be
referred to
by like numerals:
Fig. 1 is a top view of an exemplary embodiment of a wafer-processing tool;
Fig. 2 is a cross sectional view of the wafer-processing tool shown in Fig. 1
taken through line 2-2;
Fig. 3 is another cross sectional view of the wafer-processing tool shown in
Fig. 1 taken through line 3-3;
Fig. 4 is a flow chart for processing wafers using the wafer-processing tool
shown in Fig. 1;
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Fig. 5 is a top view of an alternative configuration of the wafer-processing
tool
shown in Fig. 1;
Fig. 6 is a cross sectional view of the wafer-processing tool shown in Fig. 5
taken through line 6-6;
Fig. 7 is another cross sectional view of the wafer-processing tool shown in
Fig. 5 taken through line 7-7;
Fig. 8 is a top view of another alternative configuration of the wafer-
processing tool shown in Fig. 1;
Fig. 9 is a top view of still another alternative configuration of the wafer-
processing tool shown in Fig. 1;
Fig. I O is a top view of yet another alternative configuration of the wafer-
processing tool shown in Fig. 1;
Fig. 11 is a cross sectional view of the wafer-processing tool shown in Fig.
10
taken through line 1 I-11;
Fig. 12 is another cross sectional view of the wafer-processing tool shown in
Fig. 10 taken through line 12-12;
Fig. 13 is another alternative configuration of the wafer-processing tool
shown
in Fig. 1;
Fig. 14 is a cross sectional view of the wafer-processing tool shown in Fig.
13
taken through line 14-14;
Fig. 15 is another cross sectional view of the wafer-processing tool shown in
Fig. 13 taken through line 1 S-1 S;
Fig. 16 is a cross sectional view of an exemplary embodiment of an
electroplating and/or electropolishing cell;
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Fig. 17 is a top view of a portion of the electroplating and/or
electropolishing
cells shown in Fig. 16;
Figs. 18A through 18C are cross sectional view of an exemplary embodiment
of a wafer chuck assembly;
Fig. 19 is a cross sectional view of an alternative configuration of the wafer
chuck assembly shown in Figs 18A through 18C;
Fig. 20 is a cross sectional view of another alternative configuration of the
wafer chuck assembly shown in Figs. 18A through 18C;
Fig. 21 is a cross sectional view of still another alternative configuration
of the
wafer chuck assembly shown in Figs. 18A through 18C;
Figs. 22A and 22B are cross sectional views of yet another alternative
configuration of the wafer chuck assembly shown in Figs. I 8A through 18C; .
Fig. 23 is a cross sectional view of an exemplary embodiment of a wafer
chuck;
Fig. 24 is a cross sectional view of an alternative configuration of the wafer
chuck shown in Fig. 23;
Fig. 25 is a cross sectional view of another alternative configuration of the
wafer chuck shown in Fig. 23;
Fig. 26 is a cross sectional view of still another alternative configuration
of the
wafer chuck shown in Fig. 23;
Fig. 27 is a cross sectional view of yet another alternative configuration of
the
wafer chuck shown in Fig. 23;
Fig. 28 is a cross sectional view of another alternative configuration of the
wafer chuck shown in Fig. 23;
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Fig. 29 is a cross sectional view of still another alternative configuration
of the
wafer chuck shown in Fig. 23;
Fig. 30 is a cross sectional view of yet another alternative configuration of
the
wafer chuck shown in Fig. 29;
Figs. 31A and 31B are side views of an alternative configuration of an
electroplating and/or electropolishing station shown in Fig. 16;
Figs. 32A and 32B are top views of the electroplating and/or electropolishing
station shown in Figs 31 A and 31 B;
Figs. 33A and 33B are front views of the electroplating and/or
electropolishing
station shown in Figs. 31 A and 31 B;
Fig 34 is a top view of an exemplary embodiment of an electroplating and/or
electropolishing cell shown in Figs. 31 through 33;
Fig. 35 is a side view of the exemplary embodiment of the electroplating
and/or electropolishing cell shown in Fig. 34;
Fig. 36 is a top view of a portion of the electroplating and/or
electropolishing
cell shown in Fig. 34;
Fig. 37 is a side view of the portion shown in Fig. 36;
Fig. 38 is a top view of another portion of the electroplating and/or
electropolishing cell shown in Fig. 34;
Fig. 39 is a side view of the portion shown in Fig. 38;
Figs. 40A and 40B are a cross sectional views of the portion shown in Fig. 38
taken through line 40;
Fig. 41 is a cross sectional view of the portion shown in Fig. 38 taken
through
line 41;
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Fig. 42 is another cross sectional view of the portion shown in Fig. 38 taken
through line 42;
Fig. 43 is a cross sectional view of a portion of the electroplating and/or
electropolishing cell shown in Fig. 34;
Fig. 44 is a perspective view of another portion of the electroplating and/or
electropolishing cell shown in Fig. 34;
Fig. 45 is a perspective view of still another portion of the electroplating
and/or electropolishing cell shown in Fig. 34;
Fig. 46 is a bottom view of yet another portion of the electroplating and/or
electropolishing cell shown in Fig. 34;
Fig. 47 is a side view of the portion shown in Fig. 46;
Fig. 48 is an enlarged view of a portion of the side view shown in Fig. 47;
Fig. 49 is an exploded perspective view of an exemplary embodiment of a
wafer chuck;
Fig. 50 is an exploded perspective view of an alternative configuration of the
wafer chuck shown in Fig. 49;
Fig. 51 is a cross section view of the wafer chuck shown in Fig. 49;
Figs 52A and 52B are cross section views of the wafer chuck shown in Fig.
49;
Figs. 53A to 53G are cross section views of various alternative configurations
of a portion of the wafer chuck shown in Fig. 51;
Fig. 54 is a flow chart for handling wafers using the wafer chuck shown in
Fig. 51;
Fig. 55 is a cross section view of an alternative embodiment a wafer chuck;
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Fig. 56 is a cross section view of a second alternative embodiment of a wafer
chuck;
Fig. 57 is a cross section view of a third alternative embodiment of a wafer
chuck;
Fig. 58 is a cross section view of a fourth alternative embodiment of a wafer
chuck;
Fig. 59 is a cross section view of a fifth alternative embodiment of a wafer
chuck;
Fig. 60 is a cross section view of a sixth alternative embodiment of a wafer
chuck;
Fig. 61 is a cross section view of a seventh alternative embodiment of a wafer
chuck;
Fig. 62 is a cross section view of an eighth alternative embodiment of a wafer
chuck;
Fig. 63 is a cross section view of a ninth alternative embodiment of a wafer
chuck;
Fig. 64 is a cross section view of a tenth alternative embodiment of a wafer
chuck;
Fig. 65 is a cross section view of an eleventh alternative embodiment of a
wafer chuck;
Fig. 66 is a cross section view of a twelfth alternative embodiment of a wafer
chuck; and
Fig. 67 is a top view of a wafer.
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DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
In order to provide a more thorough understanding of the present invention,
the following description sets forth numerous specific details, such as
specific
material, parameters, and the like. It should be recognized, however, that
such
description is not intended as a limitation on the scope of the present
invention, but is
instead provided to enable a more full and a more complete description of the
exemplary embodiments.
Additionally, the subject matter of the present invention is particularly
suited
for use in connection with electroplating and/or electropolishing of
semiconductor
workpieces or wafers. As a result, exemplary embodiments of the present
invention
are described in that context. It should be recognized, however, that such
description
is not intended as a limitation on the use or applicability of the present
invention.
Rather, such description is provided to enable a more full and a more complete
description of the exemplary embodiments.
With reference now to Fig. 1, a wafer-processing tool 100 is configured to
electroplate and/or electropolish semiconductor workpieces or wafers. In an
exemplary embodiment, wafer-processing tool 100 includes an electroplating
and/or
electropolishing station 102, a cleaning station 104, wafer-handling stations
108 and
110, and a robot 106.
With reference now to Fig. 4, the processing steps performed by wafer-
processing tool 100 are set forth in a flow chart format. With reference again
to Fig.
l, unprocessed semiconductor workpieces or wafers are obtained by robot 106
from
wafer-handling stations 108 and 110 (Fig. 4, block 402). The wafers are
transported
by robot 106 from wafer-handling stations 108 and 110 to electroplating and/or
electropolishing station 102 (Fig. 4, block 404). As will be described in
greater detail
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below, the wafers are electroplated and/or electropolished in electroplating
and/or
electropolishing station 102 (Fig. 4, block 406). The electroplated and/or
electropolished wafers are transported by robot 1 O6 to cleaning station 104
(Fig. 4,
block 408). The wafers are cleaned and dried in cleaning station 104 (Fig. 4,
block
410). The cleaned and dried wafers are transported by robot 106 back to wafer-
handling stations 108 and 110 (Fig. 4, block 412). The entire process can then
be
repeated for another unprocessed wafer. It should be recognized, however, that
various modifications can be made to the steps depicted in Fig. 4 and
described above
without deviating from the scope of the present invention.
With reference now to Fig. 2, in the present exemplary embodiment,
electroplating and/or electropolishing station 102 and cleaning station 104
include
five electroplating and/or electropolishing cells 112 and five cleaning cells
114.
Accordingly, as many as five wafers can be electroplated and/or
electropolished and
cleaned at one time. It should be recognized, however, that electroplating
and/or
electropolishing station 102 and cleaning station 104 can include any number
of
electroplating and/or electropolishing cells 112 and cleaning cells 114
depending on
the particular application. For example, for a low volume application,
electroplating
and/or electropolishing station 102 and cleaning station 104 can be configured
with
one electroplating and/or electropolishing cell 112 and one cleaning cell 114,
respectively. Additionally, it should be recognized that the ratio of
electroplating
and/or electropolishing cells 112 to cleaning cells 114 can vary depending on
the
particular application. For example, in an application where the
electroplating and/or
electropolishing process requires more processing time than the cleaning
process,
wafer-processing tool 100 can be configured with more electroplating and/or
electropolishing cells 112 than cleaning cells 114. Alternatively, in an
application
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where the electroplating and/or electropolishing process requires less
processing time
than the cleaning process, wafer-processing tool 100 can be configured with
fewer
electroplating and/or electropolishing cells 112 than cleaning cells 114.
As depicted in Fig. 2, electroplating and/or electropolishing cells 112 and
cleaning cells 1 I4 are configured as vertical stacks. In this manner, the
number of
wafers processed can be increased without increasing the footprint of (the
amount of
floor space occupied by) wafer-processing tool 100. In the increasingly
competitive
semiconductor industry, increasing the ratio of wafers processed per square
foot of
fabrication floor space occupied by wafer-processing tool 100 can be
advantageous.
With reference again to Fig. 1, as described above. unprocessed wafers are
obtained at wafer-handling station 108 and 1 I0, then processed wafers
are.returned to
wafer-handling stations 108 and 110. More particularly, with reference to Fig.
3, in
the present exemplary embodiment, wafer-handling station 108 and 110 (Fig. 1 )
include a wafer cassette 116 for holding wafers. As depicted in Fig. 3, robot
106 is
configured to remove an unprocessed wafer from wafer cassette 1 I6 and
transport the
wafer to any one of the electroplating and/or electropolishing cells 112 (Fig.
2).
Robot 106 is also configured to return a processed wafer from any one of the
cleaning
cells 114 (Fig. 2) to wafer cassette 116. Although a single wafer cassette 116
is
depicted in Fig. 3, it should be recognized that wafer-handling station 108
and 110
(Fig. I ) can include any number of wafer cassettes 1 I 6.
Additionally, wafer-handling station 108 and I 10 can include various
configurations depending on the particular application. For example, wafer-
handling
station 108 and 110 can each include at least one wafer cassette 116. In one
configuration, a wafer cassette I I6 containing unprocessed wafers is provided
at
wafer-handling station 108. The wafers are removed, processed, then returned
to the
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same wafer cassette 116 at wafer-handling station 108. Prior to the completion
of the
processing of wafers from wafer cassette 116 at wafer-handling station 108,
another
wafer cassette 116 containing unprocessed wafers is provided at wafer-handling
station 110. Once the wafers from wafer cassette 116 at wafer-handling station
108
are processed, wafer-processing tool 100 can begin processing the unprocessed
wafers
from wafer cassette 116 at wafer-handling station 110. The processed wafers in
wafer
cassette 116 at wafer-handling station 108 can then be removed and replaced
with yet
another wafer cassette 116 containing unprocessed wafers. In this manner,
wafer-
processing tool 100 can be operated continuously without unintended
interruption.
In another configuration, a wafer cassette 116 containing unprocessed wafer
can be provided at wafer-handling station 108. An empty wafer cassette 116 can
be
provided at wafer-handling station 110. The unprocessed wafers from wafer
cassette
116 at wafer-handling station 108 can be processed then returned to the empty
wafer
cassette 116 at wafer-handling station 110. This configuration also
facilitates
continuously operation of processing tool 100. This configuration, however,
has the
advantage that one of the two handling stations 108 and 110 can be designated
for
unprocessed wafers and the other for processed wafers. In this manner, an
operator or
a robot is less likely to mistake a wafer cassette 116 containing processed
wafers for
one with unprocessed wafers and vice versa.
With reference again to Fig. 2, wafer-processing tool 100 includes housing
unit 118 for housing the various electrical and mechanical components of wafer-
processing tool 100, such as power supplies, filters, wires, plumbing,
chemical
containers, pumps, valves, and the like. With reference again to Fig. 1, wafer-
processing tool 100 can also include a computer 132 for controlling the
operation of
wafer-processing tool 100. More particularly, computer 132 can be configured
with
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an appropriate software program to implement the processing steps set forth in
Fig. 4
and described above in conjunction with Fig. 4.
It should be recognized that various modifications can be made to the
configuration of wafer-processing tool 100 without deviating from the spirit
and/or
scope of the present invention. In this regard, in the following description
and
associated drawings, various alternative embodiments of the present invention
will be
described and depicted. It should be recognized, however, that these
alternative
embodiments are not intended to demonstrate all of the various modifications,
which
can be made to the present invention. Rather, these alternative embodiments
are
provided to demonstrate only some of the many possible modifications.
With reference to Figs. S through 7, in an alternative embodiment of the
present invention, wafer-processing tool 100 includes a wafer-handling station
500.
With reference to Fig. 7, wafer-handling station 500 includes a robot 502
configured
to raise and lower wafer cassette 116. Accordingly, when transporting wafers
in and
out of wafer cassette 116, the movement of robot 106 in the vertical direction
can be
reduced. In this manner, the operating speed of robot 106 can be increased to
facilitate overall processing speed of wafer-processing tool 100.
With reference to Fig. 8, in another alternative embodiment of the present
invention, wafer-processing tool 100 includes a robot 800 configured to move
laterally (indicated as the x-direction in Fig. 8). Accordingly, robot 800
need not
rotate about its vertical axis.
With reference to Fig. 9, in still another alternative embodiment of the
present
invention, wafer-processing tool 100 includes a stack 902 of electroplating
and/or
eiectropolishing cells 112 (Fig. 2) and cleaning cells 114 (Fig. 2).
Accordingly, the
footprint of processing tool 100 can be further reduced.
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With reference to Figs 10 through 12, in yet another alternative embodiment
of the present invention, wafer-processing tool 100 includes three stacks
1002, 1004
and 1006 of electroplating and/or electropolishing cells 112 (Fig. 12) and
cleaning
cells 114 (Fig. 12). It should be recognized that stacks 1002, 1004 and 1006
can be
configured having various combinations of electroplating and/or
electropolishing cells
112 depending on the particular application. For example, column 1002 and 1006
can
be configured to include only electroplating and/or electropoiishing cells
112.
Column 1004 can be configured to include only cleaning cells 114.
Alternatively,
each column 1002, 1004 and 1006 can be configured with combinations of
10 electroplating and/or electropolishing cells 112 and cleaning cells 114.
Wafer-
processing tool 100 also includes robot 1008 configured to move laterally
(indicated
as the y-direction in Fig. 10). With reference to Fig. 12, wafer-processing
tool 100
includes additional wafer cassette 1202 to accommodate the additional
processing
capacity of wafer-processing tool 100.
Thus far, wafer-processing tool 100 has been described with an electroplating
and/or electropolishing station 102 (Fig. 1 ) and cleaning station 104 (Fig.
2). It
should be recognized, however, that wafer-processing tool 100 can be
configured to
include only electroplating and/or electropolishing station 102 (Fig. 1). For
example,
with reference to Fig. 9, wafer-processing tool 100 can be configured with
stack 902
having only electroplating and/or electropolishing cells 112 (Fig. 1 ).
Accordingly,
wafer-processing tool 100 electroplates and/or electropolishes wafers without
cleaning the wafers. The processed wafers can be cleaned in a separate wafer-
cleaning tool. Alternatively, the processed wafers can be cleaned in a
cleaning station
in another wafer-processing tool.
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Additionally, wafer-processing tool 100 can include other wafer processing
stations. For example, with reference to Figs. 13 through 15, in another
embodiment
of the present invention, wafer-processing tool I00 includes a Chemical
Mechanical
Planarization (CMP) station 1302. In this manner, wafers can be planarized
and/or
S polished in addition to being electroplated and/or electropolished and
cleaned. The
particular order of performing these processes can vary depending on the
particular
application. For example, in one application, the wafer can be electroplated
at
electroplating and/or electropolishing station 102, cleaned at cleaning
station 104,
then planarized at CMP station 1302. In another application, the wafer can be
initially
electropolished at electroplated and/or electropolishing station 102, cleaned
at
cleaning station I04, then planarized at CMP station 1302.
Having thus described various exemplary embodiments of a wafer-processing
tool, an exemplary embodiment of electroplating and electropolishing cell 112
will be
described below. With reference now to Figs. 16 and 17, in one exemplary
embodiment of the present invention, wafer electroplating and/or
electropolishing
cell 112 includes an electrolyte solution receptacle 1608, a wafer chuck 1604,
and a
wafer chuck assembly 1600.
With reference to Fig. 16, in the present exemplary embodiment, electrolyte
solution receptacle 1608 holds the electrolyte solution for electroplating
and/or
electropolishing of a wafer 1602. During the electroplating and/or
electropolishing
process, wafer chuck 1604 holds wafer 1602. Wafer chuck assembly 1600
positions
wafer chuck 1604 within electrolyte solution receptacle 1608. Wafer chuck
assembly
I 600 also rotates wafer chuck 1604 to enhance the uniformity of the
electroplating
and/or electropoIishing process.
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In the present exemplary embodiment. with reference to Fig. I7, electrolyte
solution receptacle 1608 is preferably divided into sections 1620, 1622, 1624,
1626,
1628 and 1630 by section walls 1610, 1612. 1614, 1616 and 1618. It should be
recognized, however, that electrolyte solution receptacle 1608 can be divided
into any
number of sections by any number of appropriate sections walls depending on
the
particular application.
With reference to Fig. 16, in the present exemplary embodiment, a pump 1654
pumps an electrolyte solution 1656 from a reservoir 1658 into electrolyte
solution
receptacle 1608. More particularly, electrolyte solution 1656 flows through a
pass
filter 1652 and Liquid Mass Flow Controllers (LMFCs) 1646, 1648 and 1650. Pass
filter 1652 removes contaminants and unwanted particles from electrolyte
solution
1656. LMFCs 1646, 1648 and 1650 control the flow of electrolyte solution 1656
into
sections 1620, 1624 and 1628 (Fig. 17), respectively. It should be recognized,
however, that electrolyte solution 1656 can be provided using any convenient
method
depending on the particular application.
As described above, during the electroplating and/or electropolishing process,
wafer chuck 1604 holds wafer 1602. In the present exemplary embodiment, robot
106 inserts or provides wafer 1602 into wafer chuck 1604. As discussed above,
robot
106 can obtain wafer 1602 from wafer cassette 116 (Fig. 3) or from a previous
processing station or processing tool. Wafer 1602 can also be loaded into
wafer
chuck 1604 manually by an operator depending on the particular application.
As will be described in greater detail below, after receiving wafer 1602,
wafer
chuck 1604 closes to hold wafer 1602. Wafer chuck assembly 1600 then positions
wafer chuck 1604 and wafer 1602 within electrolyte solution receptacle 1608.
More
particularly, in the present exemplary embodiment, wafer chuck assembly 1600
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positions wafer chuck 1604 and wafer 1602 above section walls 1610, 1612,
1614,
1616 and 1618 (Fig. 17) to form a gap between the bottom surface of wafer 1602
and
the tops of section walls 1610, 1612, 1614, 1616 and 1618 (Fig. 17).
In the present exemplary embodiment, electrolyte solution 1656 flows into
sections 1620, 1624 and 1628 (Fig. 17), and contacts the bottom surface of
wafer
1602. Electrolyte solution 1656 flows through the gap formed between the
bottom
surface of wafer 1602 and section walls 1610, 1612, 1614, 1616 and 1618 (Fig.
17).
Electrolyte solution 1656 then returns to reservoir 1658 through sections
1622, 1626
and 1630 (Fig. 17).
As will be described in greater detail below, wafer 1602 is connected to one
or
more power supplies 1640, 1642 and 1644. Also, one or more electrodes 1632,
1634
and 1636 disposed within electrolyte solution receptacle 1608 are connected to
power
supplies 1640, 1642 and 1644. When electrolyte solution 1656 contacts wafer
1602, a
circuit is formed to electroplate and/or to electropolish wafer 1602. When
wafer 1602
is electrically charged to have negative electric potential relative to
electrodes 1632,
1634 and 1636, wafer 1602 is electroplated. When wafer 1602 is electrically
charged
to have positive electric potential relative to electrodes 1632, 1634 and
1636, wafer
1602 is suitably electropolished. Additionally, when wafer 1602 is
electroplated,
electrolyte solution 1656 is preferably a sulfuric acid solution. When wafer
1602 is
20 electropolished, electrolyte solution 1656 is preferably a phosphoric acid
solution. It
should be recognized, however, that electrolyte solution 1656 can include
various
chemistries depending on the particular application.
Additionally, as will be described in greater detail below, wafer chuck
assembly 1600 can rotate and/or oscillate wafer 1602 to facilitate a more
uniform
electroplating and/or electropolishing of wafer 1602. After wafer 1602 is
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electroplated and/or electropolished, wafer 1602 is removed from electrolyte
solution
receptacle 1608. More particularly, wafer chuck assembly 1600 lifts wafer
chuck
1604 from electrolyte solution receptacle 1608. Wafer chuck 1604 then opens.
Robot
106 removes wafer 1602 from wafer chuck 1604, then provides another wafer 1602
for electroplating and/or electropolishing. For a more detailed description of
electropolishing and electroplating processes, see U.S. patent application
Ser. No.
09/232,864, entitled PLATING APPARATUS AND METHOD, filed on January 15,
1999, the entire content of which is incorporated herein by reference, and PCT
patent
application No. PCT/US99/15506, entitled METHODS AND APPARATUS FOR
10 ELECTROPOLISHING METAL INTERCONNECTIONS ON SEMICONDUCTOR
DEVICES, filed on August, 7, 1999, the entire content of which is incorporated
herein by reference.
As alluded to earlier, specific details related to electroplating and/or
electropolishing cell 112 have been provided above to enable a more full and a
more
complete description of the present invention. As such, various aspects of
electroplating and/or eiectropolishing cell 112 can be modified without
deviating from
the spirit and/or scope of the present invention. For example, although
electroplating
and/or electropolishing cell 112 has been depicted and described as having
electrolyte
solution receptacle 1608 with a plurality of sections, electroplating and/or
electropolishing cell 112 can include a static bath.
Having thus described an exemplary electroplating and/or electropolishing cell
and method, an exemplary embodiment of wafer chuck 1604 and wafer chuck
assembly 1600 will be described below. As a preliminary matter, for the sake
of
clarity and convenience, wafer chuck 1604 and wafer chuck assembly 1600 will
hereafter be described in connection with electroplating of a semiconductor
wafer.
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However, it should be recognized that wafer chuck 1604 and wafer chuck
assembly
1600 can be used in connection with any convenient wafer process, such as
electropolishing, cleaning, etching, and the like. Additionally, it should be
recognized
that wafer chuck 1604 and wafer chuck assembly 1600 can be used in connection
with
processing of various workpieces other than semiconductor wafers.
With reference to Figs. 18A to 18C, as described above, during the
electroplating and/or electropolishing process, wafer chuck assembly 1600
positions
wafer chuck 1604 within electrolyte receptacle 1608 (Fig. 16). Additionally,
wafer
chuck assembly 1600 is configured to open and close wafer chuck 1604 for
insertion
and removal of wafer 1602.
More particularly, in the present exemplary embodiment, wafer chuck
assembly 1600 includes an actuator assembly 1860 and a spring assembly 1894.
Actuator assembly 1860 is configured to move wafer chuck 1604 between a first
position and a second position. In the present embodiment, actuator assembly
1860 is
configured to move wafer chuck 1604 between a raised position and a lowered
position. In the first position, spring assembly 1894 is configured to open
wafer
chuck 1604 to permit removal and insertion of wafer 1602. In the second
position,
spring assembly 1894 is configured to close wafer chuck 1604.
In the present embodiment, actuator assembly 1860 includes a motor 1828,
gears 1822 and 1824, and lead screw 1820. Motor 1828 is connected to shaft
1802
through bracket 1816, lead screw 1820 and gears 1822 and 1824. More
particularly,
motor 1828 turns lead screw 1820 through gears 1822 and 1824 to translate
bracket
1816 along a guide rail 1826. Bracket 1816 is attached to shaft 1802, which is
rigidly
attached to top section 1858 of wafer chuck 1604. In this manner, motor 1828
can
lower and raise wafer chuck 1604. It should be recognized, however, that wafer
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chuck 1604 can be raised and lowered using any convenient apparatus and
method,
such as pneumatic actuators, magnetic forces, and the like. Also, it should be
recognized that motor 1828 can include a direct current servomotor, stepper
motor,
and the like.
Although a single guide rail 1826 is depicted in Figs. 18A through 18C, it
should be recognized any number of guide rails 1826 can be used depending on
the
particular application. Additionally, with reference to Fig. 19, in an
alternatively
embodiment of the present invention, joints 1902 and 1904 are disposed between
bracket 1816 and an additional bracket 1906. Joints 1902 and 1904 permit
movement
between bracket 1906 and 1816 as lead screw 1820 raises and lowers wafer chuck
1604. As such, bracket 1816 is less likely to seize on guide rail 1826. In the
present
exemplary embodiment, joints 1902 and 1904 are universal joints. It should be
recognized, however, that any convenient type of joint can be used to permit
movement between bracket 1906 and 1816.
With continued reference to Figs. 18A through 18C, spring assembly 1894
includes a collar 1804, a plurality of rods 1806, and a plurality of springs
1808. Rods
1806 are rigidly fixed to collar 1804 and to bottom section 1856 of wafer
chuck 1604.
Springs 1808 are disposed around rods 1806 and between collar 1804 and top
section
1858 of wafer chuck 1604. Additionally, collar 1804 is not attached to shaft
1802.
Accordingly, as depicted in Fig. 18B, as wafer chuck 1604 is raised, collar
1804
contacts a lid 1810. As depicted in Fig. 18C, rods 1806 prevent bottom section
1856
of wafer chuck 1604 from rising any further. However, springs 1808 compress to
permit top section 1858 of wafer chuck 1604 to continue to rise. Thus, wafer
chuck
1604 is opened for inserting and removing of wafer 1602.
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In the manner described above and as depicted in Figs. 18A through 18C, the
single action of raising wafer chuck 1604 also opens wafer chuck 1604. The
reverse
action of lowering wafer chuck 1604 also closes wafer chuck 1604. More
particularly, starting from Fig. 18C, when wafer 1602 has been positioned
within
wafer chuck 1604, motor 1828 begins to lower wafer chuck i 604. As depicted in
Fig.
18B, as motor 1828 lowers wafer chuck 1604, spring 1808 extend to close wafer
chuck 1604.
In addition to the force applied by spring 1808, additional force is applied
to
hold together wafer chuck 1604 by applying a vacuum and/or a reduced pressure
gas
to cavity 1830 foamed between top section I 858 and bottom section 1856 of
wafer
chuck 1604. More particularly, with reference to Fig. 18B, wafer chuck
assembly
1600 includes a slip-ring assembly 1838 configured with inlets 1870 and 1872.
Slip-
ring assembly 1838 also includes a plurality of seals 1842 configured to form
cavities
1866 and 1868. In the present exemplary embodiment, vacuum and/or reduced
pressure gas is applied through inlet 1870, channel I 874, and line 1832 to
cavity
1830. In order to help seal cavity 1830, wafer chuck 1604 also includes seals
1878
disposed between top section 1858 and bottom section 1856.
Additionally, with reference to Fig. 18B, as described in brief above and as
will be described in greater detail below, an electric charge is applied to
wafer 1602
during the electroplating and/or electropolishing process. More particularly,
in the
present exemplary embodiment, slip-ring assembly 1838 includes a brush 1844,
springs 1846. and screws 1848. Additionally, as will be described in greater
detail
below, wafer chuck 1604 includes a conducting member 1880, which electrically
contacts line 1850, and a spring member 1882, which electrically contacts
wafer
1602. Accordingly, the electric charge is applied to wafer 1602 through screw
1848,
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spring 1846. brush 1844, shaft 1802, line 1850. conducting member 1880, and
spring
member 1882. Thus, screw 1848, spring 1846, brush 1844, shaft 1802 , line
1850,
conducting member 1880, and spring member 1882 are formed from an electrically
conducting material. Additionally, as shaft 1802 can rotate, brush 1844 is
formed
from an electrically conducting and low friction material, such as graphite.
As will be described in greater detail below, to help isolate spring member
1882 and conducting member 1880 from the electrolyte solution during the
electroplating and/or electropolishing process, wafer chuck 1604 includes a
seal
member 1884. In the present exemplary embodiment of the present invention, a
positive pressure gas is applied to a cavity 1892 to check the seal quality of
seal
member 1884. More particularly, pressure gas is applied through inlet 1872,
channel
1876, and line 1852. Wafer chuck 1604 also includes seals 1886 and 1888 to
help
seal cavity 1892. Alternatively, a vacuum and/or a reduced pressure gas can be
applied to cavity 1892 to check the seal quality of seal member 1884. After
wafer
chuck 1604 is removed from the electrolyte solution, positive pressure gas can
be
applied to cavity 1892 to purge electrolyte solution from wafer chuck 1604.
As alluded to earlier, wafer chuck assembly 1600 is configured to rotate wafer
chuck 1604 to enhance the uniformity of the electroplating and/or
electropolishing
process. More particularly, during the electroplating and/or electropolishing
process,
wafer chuck assembly 1600 rotates wafer chuck 1604 at about 5 revolutions per
minute to about 100 revolutions per minute. It should be recognized, however,
that
wafer chuck 1604 can be rotated at various speeds depending on the particular
application.
Additionally, as will be described in greater detail below, wafer chuck
assembly 1600 is configured to rotate wafer chuck 1604 to help remove
electrolyte
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solution from wafer chuck 1604 after the electroplating and/or
electropolishing
process. During this process, wafer chuck assembly 1600 rotates wafer chuck
1604 at
about 300 revolutions per minute to about 5000 revolutions per minute, and
preferably about 500 revolutions per minute. It should be recognized, however,
that
wafer chuck assembly 1600 can rotate wafer chuck 1604 at various speeds
depending
on the particular application. As depicted in Fig. 20, during this process,
wafer chuck
1604 can be rotated when wafer chuck 1604 is in an open position. Accordingly,
in
an alternative embodiment, wafer chuck assembly 1600 includes bearing 2002
(Fig.
20). In the present exemplary embodiment, bearing 2002 is depicted as being
disposed between collar 1804 and lid 1810. It should be recognized, however,
that
bearing 2002 can be disposed in various locations depending on the particular
application. For example, if collar 1804 is removed or reduced in size,
bearing 2002
can be provided between top section 1858 and lid 1810. Additionally, it should
be
recognized, however, that wafer chuck assembly 1600 can rotate wafer chuck
1604 at
various speeds depending on the particular application.
With reference to Fig. 18A, wafer chuck assembly 1600 includes rotational
assembly 1864 to rotate wafer chuck 1604. In the present exemplary embodiment,
rotational assembly 1864 includes a motor 1836 and a drive belt 1834 connected
to
shaft 1802. In the present exemplary embodiment; motor 1836 and drive belt
1834
are disposed below bracket 1816. It should be recognized, however, that motor
1836
and drive belt 1834 can be disposed in various locations to rotate shaft 1802.
For
example, with reference to Fig. 21, wafer chuck assembly 1600 is depicted with
motor
1836 and drive belt 1834 disposed above bracket 1816. Alternatively, motor
1836
can be connected to shaft 1802 through gears rather than drive belt 1834.
Motor 1836
can also be connected directly to shaft 1802. In the present embodiment, motor
1836
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can include a direct current servomotor. a stepper motor, and the like.
Additionally, it
should be recognized that rotational assembly 1864 can include various other
mechanisms for rotating wafer chuck 1604. For example, rotational assembly
1864
can be configured as an electro-magnetic system to rotate wafer chuck 1604.
With reference to Figs. 18A through 18C, in the present exemplary
embodiment, shaft 1802 is formed from a metal or metal alloy resistant to
corrosion,
such as stainless steel. In order to reduce friction, the surface of shaft
1802 contacting
seals 1842 and brush 1844 is machined to a surface roughness less than about 5
micron, and preferably less than about 2 micron. Additionally, in the present
exemplary embodiment. wafer chuck assembly 1600 includes bearings 1812 and
1814
disposed between shaft 1802 and lid 1810. Wafer chuck assembly 1600 also
includes
bearings 1818 disposed between shaft 1802 and bracket 1816. Bearings 1812,
1814,
1818 can include ball-bearings, bushings, low-friction material, and the like
As described above, slip-ring assembly 1838 is configured to supply vacuum
and/or reduced pressure gas, reduced pressure gas, pressure gas, and
electricity to
shaft 1802. Thus far, as particularly depicted in Figs. 18A through 18C, slip-
ring
assembly 1838 has been shown as fixed to bracket 1816. In contrast, with
reference
to Figs. 22A and 22B, in an alternative embodiment of the present invention,
wafer
chuck assembly 1600 includes a slip-ring assembly 2200, which remains fixed
when
wafer chuck 1604 is raised and lowered. More particularly, shaft 1802 slides
through
slip-ring assembly 2200 as it is raised and lowered.
In the following descriptions and associated drawings, various alternative
embodiments of the present invention are described and depicted. It should be
recognized that these alternative embodiments are not meant to include all the
possible modifications and potential alterations, which can be made to the
present
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invention. Rather, these alternative embodiments are meant to demonstrate some
of
the potential modifications and alterations.
With reference to Fig. 23, in an alternative embodiment, conducting member
1880 of wafer chuck I 604 is depicted without seal 1888 (Fig. 18A).
Additionally, a
spring 2302 applies the charge to conducting member 1880. In contrast to wire
1890
depicted in Fig. 18C, spring 2302 lifts clear of conducting member 1880 when
wafer
chuck 1604 opens.
With reference now to Fig. 24, in another alternative embodiment, wafer
chuck 1604 is depicted with seal member 1884 having a Z-shaped cross-sectional
profile. In comparison to a seal member 1884 having an L-shaped cross-
sectional
profile (Fig. 18A), the Z-shaped cross-sectional profile can hold spring
member 1882
more securely in place. It should be recognized, however, that seal member
1884 can
be formed having various cross-sectional profiles. In this regard, a number of
these
possible profiles will be described and depicted below.
With reference now to Fig. 25, in still another alternative embodiment, wafer
chuck 1604 is depicted with lines 1832 and 1852 formed into top section 1858.
It
should be recognized, however, that lines 1832 and 1852 can be formed in
various
manner. For example, grooves can be formed along the top surface of top
section
1858. Lines 1832 and 1852 can be tubes inserted into the grooves. In this
manner,
lines 1832 and 1852 can be held more securely.
With reference now to Fig. 26, in yet another alternative embodiment, wafer
chuck 1604 is depicted with rods 1806 attached to bottom section 1856 using
nuts
2602. The ends of rods 1806 and nuts 2602 are sealed with caps 2604 to protect
them
from the electrolyte solution during the electroplating and/or
electropolishing process.
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With reference now to Fig. 27, in an alternative embodiment, the embodiment
shown in Fig. 26 is depicted with seal member 1884 having a Z-shaped cross-
sectional profile. As described above, this cross-sectional profile can hold
spring
member 1882 more securely.
With reference now to Fig. 28, in another alternative embodiment, wafer
chuck 1604 is depicted having line 1852. Accordingly, when wafer chuck 1604 is
closed, a vacuum and/or a reduced pressure gas is first applied to line 1852
to increase
the force holding together wafer chuck 1604. After the electroplating and/or
electropolishing process, a pressure gas can be applied to line 1852 to help
purge
electrolyte from wafer chuck 1604.
With reference now to Fig. 29, in still another alternative embodiment, wafer
chuck 1604 is depicted having a line 2902 to apply a vacuum and/or a reduced
pressure gas and pressure gas to the surface of wafer 1602. Accordingly, after
wafer
chuck 1604 is closed, a vacuum andlor a reduced pressure gas is applied to
line 1852
and line 2902 to increase the force holding together wafer chuck 1604. After
the
electroplating and/or electropolishing process, a pressure gas can be applied
to line
1852 to help purge electrolyte from wafer chuck 1604. Then, wafer chuck 1604
is
opened, preferably with a gap of about 1 millimeter to about 3 millimeter,
preferably
about 1.5 millimeter. After wafer chuck 1604 is opened, pressure gas can be
applied
to line 2902 to help dislodge wafer 1602.
With reference now to Fig. 30, in yet another alternative embodiment, wafer
chuck 1604 is depicted having a single line 3002. Accordingly, vacuum and/or a
reduced pressure gas and pressure gases are applied at the same time to cavity
3004
and to the surface of wafer 1602.
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With reference to Figs. 31 through 33. a more detailed depiction of an
exemplary embodiment of electroplating and/or electropolishing station 102 is
shown.
As described above, electroplating and/or electropolishing station 102
includes one or
more electroplating and/or electropolishing cells 112. More particularly, in
the
present exemplary embodiment, electroplating and/or electropolishing station
102
includes three electroplating and/or electropolishing cells 112 mounted in a
frame
3202. As alluded to earlier, however, any number of electroplating and/or
electropolishing cells 112 can be mounted in frame 3202 depending on the
particular
application.
In the present exemplary embodiment. electroplating and/or electropolishing
station 102 also includes guide rails 3204 and an air cylinder 3206 for moving
wafer
chuck assembly 1600. More particularly, air cylinder 3206 translates wafer
chuck
assembly 1600 along guide rails 3204 attached to frame 3202. In this manner,
as
depicted in Figs. 32A and 32B, wafer chuck assembly 1600 and wafer chuck 1604
can
be retracted from electrolyte receptacle 1608 for servicing of electroplating
and/or
electropolishing cell 112 including wafer chuck assembly 1600 and wafer chuck
1604. More particular, in Fig. 32B, electroplating and/or electropolishing
cell 112 is
depicted with wafer chuck assembly 1600 retracted in an open position. In Fig.
32A,
electroplating and/or electropolishing cell 112 is depicted with wafer chuck
assembly
1600 in a closed position over electrolyte receptacle 1608. It should be
recognized,
however, that various actuators can be used to retract wafer chuck assembly
1600.
With reference to Figs 31A, 32A and 33A, electroplating and/or
electropolishing cell 112 includes electrolyte solution receptacle 1608 and
wafer
chuck assembly 1600. As depicted in Fig. 32A, wafer chuck assembly 1600
includes
lid 1810 to cover electrolyte solution receptacle 1608. As such, lid 1810
includes an
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exhaust hole 3208 for removing vapors from within electrolyte solution
receptacle
1608. In this manner, each electroplating and/or electropolishing cell 112 in
electroplating and/or electropolishing station I 02 can be individually
vented, thus
reducing the need for a large ventilation system for the entire electroplating
and/or
S electropolishing station 102 (Figs. 32A and 33A).
As depicted in Figs 3 I A and 32A, wafer 1602 can be inserted into and
removed from electrolyte solution receptacle 1608 through slot 1892. More
particularly, as describe above, robot 106 transports wafer 1602 into and out
of
electrolyte solution receptacle 1608. Although slot I 892 is depicted as being
formed
in electrolyte receptacle 1608, slot 1892 can also be formed in lid 1810.
As described earlier, wafer 1602 is held by wafer chuck 1604 (Fig. 18A).
With reference to Fig. 31A, in the present exemplary embodiment, wafer chuck
assembly 1600 lowers wafer 1602 into electrolyte receptacle 1608 to be
electroplated
and/or electropolished. After the electroplating and/or electropolishing
process is
complete, wafer chuck assembly 1600 raises wafer 1602 to be unloaded and a new
wafer 1602 to be loaded.
With reference now to Fig. 37, as described above, wafer chuck assembly
1600 (Fig. 31 A) includes bracket 1816. In the present exemplary embodiment,
bracket 1816 is connected to wafer chuck 1604 through shaft 1802 {Fig. 18A).
More
particularly, as will be described in greater detail below, shaft 1802 is
fixed to top
section 1858 of wafer chuck 1604. Additionally, slip-ring assembly 1838 is
fixed to
bracket 1816. Accordingly, shaft 1802 is disposed within slip-ring assembly
1838.
With reference now to Fig. 35, it should be recognized that a portion of wafer
chuck assembly 1600 lies below lid 1810. With reference now to Fig. 34, in the
present exemplary embodiment, bracket 1816 includes guide rails 1826. More
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particularly, in the present exemplary embodiment, each guide rail 1826
include a rod
3402 disposed within a bushing 3404. Rod 3402 is mounted to lid 1810 and
bushing
3404 is connected to bracket 1816. Additionally, in the present exemplary
embodiment, four guide rails 1826 are provided. It should be recognized,
however,
that any number of guide rails 1826 can be used depending on the particular
application.
Thus, with reference now to Fig. 35, motor 1828 is configured to move
bracket 1816 along guide rails 1826. More particularly motor 1828 engages with
lead
screw 1820 to move bracket 1816. Additionally, as described above, in the
present
exemplary embodiment, bracket 1816 is connected to bracket 1906. More
particularly, brackets 1816 and 1906 are connected through joints 1902 and
1904 to
permit movement between brackets 1816 and 1906. As described earlier, joints
1902
and 1904 reduces the likelihood of brackets 1816 and 1906 seizing on guide
rails
1826.
With reference now to Fig. 37. as described above, wafer chuck 1604 is
configured to be rotated. With reference now to Fig. 35, motor 1836 is
configured to
rotate wafer chuck 1604 (Fig. 37). More particularly, in the present exemplary
embodiment, motor 1836 rotates shaft 1802 through drive belt 1834. With
reference
again to Fig. 37, shaft 1802 is fixed to top section 1858 of wafer chuck 1604.
Additionally, shaft 1802 rotates within slip-ring assembly 1838.
With continued reference to Fig. 37, as described above, wafer chuck 1604
includes a plurality of spring assemblies 1894 configured to open and close
wafer
chuck 1604. More particularly, in the present exemplary embodiment, wafer
chuck
1604 includes six spring assemblies 1894. It should be recognized, however,
that any
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number of spring assemblies 1894 can be used depending on the particular
application.
With continued reference to Fig. 37, in the present exemplary embodiment,
each spring assembly 1894 includes rod 1806 with one end formed with a head
portion rather than collar 1804 (Fig. 18A). More particularly, with reference
to Figs.
40A and 40B, one end of rod 1806 is fixed to bottom section 1856 of wafer
chuck
1604. The other end of rod 1806 includes a head portion 4002. Additionally,
spring
1808 is disposed around rod 1806 and between top section 1858 and head portion
4002. Accordingly, when wafer chuck 1604 is in a lowered position. spring 1808
is
extended to apply a force to hold top section 1858 and bottom section 1856
closed.
As wafer chuck 1604 is raised, head portion 4002 eventually contacts the
underside of
lid 1810 (Fig. 34). Accordingly, spring 1808 becomes compressed, and rod 1806
separates top section 1858 from bottom section 1856 to open wafer chuck 1604.
As described above, with reference to Fig. 37, in addition to the force
applied
by spring assemblies 1894, a vacuum and/or reduced pressure is applied to hold
together wafer chuck 1604. With reference to Fig. 41, in the present exemplary
embodiment, vacuum and/or reduced pressure is applied to cavity 1830 formed by
a
seal 4104. In earlier descriptions and as depicted in Figs. 18A through 18C,
cavity
1830 was formed in bottom section 1856 and sealed by seals 1878. In
comparison,
with reference again to Fig. 41, seal 4104 can be more easily installed into
bottom
section 1856 using any convenient fastening device and/or method, such as
screws,
bolts, adhesives, and the like. More particularly, in the present exemplary
embodiment, seal 4104 is attached using a ring 1406, which can be fastened to
bottom
section 1856 using any convenient fastening device, such as screws, bolts, and
the
like. Ring 1406 helps to distribute the force applied by the fastening devices
around
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seal 4104. Additionally, the use of seal 4104 can be more cost efficient and
more
reliable than forming cavity 1830 in bottom section 1856. Seal 4104 can
include any
flexible compliant material such as Viton, (fluorocarbon} rubber, silicon
rubber, and
the like.
With reference to Fig. 42, as described above, vacuum and/or reduced pressure
can be supplied to cavity 1892 to check and/or enhance the seal formed by seal
member 1884. Additionally, as also described above, pressure gas can be
supplied to
cavity 1892 to check the seal formed by seal member 1884, to enhance the seal
formed by seal member 1884, to purge residual electrolyte solution, and
various other
purposes.
However, when vacuum and/or reduced pressure gas is applied to cavity 1892,
some of the vacuum and/or reduced pressure gas can seep into the interface
between
wafer 1602 and top section 1852. As such, even when the vacuum and/or reduced
pressure gas is stopped. wafer 1602 can remain adhered to top section 1852
when
wafer chuck 1604 (Fig. 37) is in an open position, thus making removal of
wafer 1602
more difficult. With reference to Figs. 46 through 48, to prevent wafer 1602
(Fig. 42)
from adhering to top section 1852 (Fig. 42), a textured pad 4600 can be
provided
between wafer 1602 (Fig. 42) and top section 1852 (Fig. 42). In the present
embodiment, textured pad 4600 includes a multitude of grooves 4602 formed
throughout the surface to be in contact with wafer 1602 (Fig. 42). As such,
any
vacuum and/or reduced pressure gas, which seeps behind wafer 1602 (Fig. 42),
can
more easily escape. Consequently, wafer 1602 (Fig. 42) is less likely to
adhere to top
section 1852 (Fig. 42).
With reference again to Figs. 41 and 42, in the present exemplary
embodiment, vacuum, reduced pressure, and/or pressure gases are supplied to
cavities
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1830 and 1892 through fittings 4102 (Fig. 41 ) and 4202 (Fig. 42),
respectively. With
reference now to Fig. 38, vacuum, reduced pressure, and/or pressure gases are
supplied to fitting 4102 (Fig. 41) and fitting 4202 (Fig. 42) through line
1832 from
channel 1874 and line 1852 from channel 1876, respectively.
With reference to Fig. 43, vacuum, reduced pressure, and/or pressure gases are
supplied to channels 1874 and 1876 formed in shaft 1802 through slip-ring
assembly
1838. As described above, slip-ring assembly 1838 is configured to supply
vacuum
and/or reduced pressure into shaft 1802 even as shaft 1802 is rotating. More
particularly, as described above, seals 1842 form cavities 1866 and 1868 (Fig.
18B) in
between shaft 1802 and slip-ring assembly 1838, into which vacuum and/or
reduced
pressure can be introduced through inlets 1870 and 1872.
With reference to Fig. 16, as described above, maintaining wafer 1602 in
parallel alignment with the surface level of electrolyte solution 1656 in
electrolyte
receptacle 1608 helps to enhance the uniformity of the electroplating and/or
electropolishing process. In this regard, with reference to Fig. 43, the
alignment of
bracket 1816 can be configured to be parallel with wafer chuck 1858.
With reference to Fig. 44, the alignment of bracket 1816 with respect to slip-
ring assembly 1838 can be adjusted by variously adjusting a plurality of
screws 4312
and a plurality of set screws 4314. More particularly, the gap between bracket
1$16
and slip-ring assembly 1838 can be increased and decreased by adjusting screws
4312
and set-screws 4314, respectively. In the present embodiment, the use of at
least three
screws 4312 and three set-screws 4314 permits slip-ring assembly 1838 to be
essentially gimbaled relative to bracket 1816. It should be recognized,
however, that
various devices and methods can be employed to permit the alignment of bracket
1816 and slip-ring assembly 1838 to be adjusted.
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With reference to Fig. 45, the alignment of top section 1858 with respect to
shaft 1802 can be adjusted by variously adjusting a plurality of screws 4304
and a set
screw 4306. In the present embodiment, the adjustment of screws 4304 and set
screw
4306 adjusts the alignment of top section 1858 with respect to a stem piece
4302.
More particularly, the gap between top section 1858 and stem piece 4302 can be
adjusted using screws 4304 and set screw 4306. In the present embodiment, the
use
of three screws 4304 and the location of set screw 4306 at the center of top
section
1858 and stem piece 4302 permits top section 1858 to be essentially gimbaled
relative
to stem piece 4302.
Additionally, in the present embodiment, stem piece 4302 is attached to shaft
1802 with a plurality of bolts 4308. In this manner, top section 1858 can be
removed
from shaft 1802 without having to necessarily reset its alignment. As alluded
to
earlier, wafer chuck 1604 (Fig. 37) can be removed for various purposes, such
as
inspection, repair, maintenance, and the like. To facilitate ease of re-
alignment
afterwards, with reference to Fig. 43, in the present embodiment, stem piece
4302 and
shaft 1802 are joined using a tenon and mortise shaped joint. Additionally,
bolts 4308
only contact stem piece 4302 and shaft 1802. In this manner, adjustment of
bolts
4308 does not affect the alignment of top portion 1858 to stem piece 4302.
Having thus described various exemplary embodiments of a wafer chuck
assembly, various exemplary embodiments of wafer chuck 1604 will be described
below. With reference now to Figs. 49, wafer chuck 1604 includes bottom
section
1856 and top section 1858. Bottom section 1856 is formed having an opening to
expose the bottom surface of wafer 1602 during the electroplating and/or
electropolishing process.
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In one exemplary embodiment. bottom section 1856 and top section 1858 are
formed from any convenient material electrically insulated and resistant to
acid and
corrosion, such as ceramic, polytetrafluoroethylene (commercially known as
TEFLON), Polyvinyl Choride (PVC), PolyVinylindene Fluoride (PVDF),
S Polypropylene, and the like. Alternatively, bottom section 1856 and top
section 1858
can be formed from any electrically conducting material (such as metal, metal
alloy,
and the like), coated with material, which is electrically insulating and
resistant to
acid and corrosion. In the present exemplary embodiment, bottom section 1856
and
top section 1858 are formed from a sandwich of a layer of metal with a layer
of
10 plastic. The metal layer provides structural integrity and strength. The
plastic layer
provides protection against the electrolyte solution.
Wafer chuck 1604 according to various aspects of the present invention
fiurther includes a spring member 1882, a conducting member 1880, and a seal
member 1884. As alluded to earlier, the present invention is particular well
suited for
15 use in connection with holding semiconductor wafers. In general,
semiconductor
wafers are substantially circular in shape. Accordingly, the various
components of
wafer chuck 1604 (i.e., bottom section 1856, seal member 1884, conducting
member
1880, spring member 1882, and top section 1858) are depicted as having
substantially
circular shape. It should be recognized, however, that the various components
of
20 wafer chuck 1604 can include various shapes depending on the particular
application.
For example, with reference to Fig. 67, wafer 6700 can be formed with a flat
edge
6702. Thus, the various components of wafer chuck 1604 can be formed to
conform
with flat edge 6702.
With reference now to Fig. 51, when wafer 1602 is disposed between bottom
25 section 1856 and top section 1858, in accordance with one aspect of the
present
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invention, spring member 1882 preferably contacts wafer 1602 around the outer
perimeter of wafer 1602. Spring member 1882 also preferably contacts
conducting
member 1880. Thus, when an electric charge is applied to conducting member
1880,
the electric charge is transmitted to wafer 1602 through spring member 1882.
As depicted in Fig. 51, in the present exemplary embodiment, spring member
1882 is disposed between wafer 1602 and lip portion 1880a of conducting member
1880. Accordingly, when pressure is applied to hold bottom section 1856 and
top
section 1858 together, spring member 1882 conforms to maintain electrical
contact
between wafer 1602 and conducting member 1880. More particularly, the tops and
bottoms of the coils in spring member 1882 contact wafer 1602 and lip portion
1880a,
respectively. Additionally, spring member 1882 can be joined to lip portion
1880a to
form a better electrical contact using any convenient method, such as
soldering,
welding, and the like.
The number of contact points formed between wafer 1602 and conducting
1 S member 1880 can be varied by varying the number of coils in spring member
1882.
In this manner, the electric charge applied to wafer 1602 can be more evenly
distributed around the outer perimeter of wafer 1602. For example, for a 200
millimeter (mrn) wafer, an electric charge having about 1 to about 10 amperes
is
typically applied. If spring member 1882 forms about 1000 contact points with
wafer
1602, then for the 200 mm wafer, the applied electric charge is reduced to
about 1 to
about 10 milli-amperes per contact point.
In the present exemplary embodiment, conducting member 1880 has been thus
far depicted and described as having a lip section 1880a. It should be
recognized,
however, that conducting member 1880 can include various configurations to
electrically contact spring member 1882. For example, conducting member 1880
can
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be formed without lip section 1880a. In this configuration, electrical contact
can be
formed between the side of conducting member 1880 and spring member 1882.
Moreover, conducting member 1880 can be removed altogether. An electric charge
can be applied directly to spring member 1882. However, in this configuration,
hot
spots can form in the portions of spring member 1882 where the electric charge
is
applied.
Spring member 1882 can be formed from any convenient electrically
conducting, and corrosion-resistant material. In the present exemplary
embodiment,
spring member 1882 is formed from a metal or metal alloy (such as stainless
steel,
spring steel, titanium. and the like). Spring member 1882 can also be coated
with a
corrosion-resistant material (such as platinum, gold, and the like). In
accordance with
one aspect of the present invention, spring member 1882 is formed as a coil
spring
formed in a ring. However, conventional coil springs typically have cross
sectional
profiles, that can vary throughout the length of the coil. More specifically,
in general,
conventional coil springs have elliptical cross-sectional profiles, with a
long diameter
and a short diameter. In one part of the coil spring, the long and short
diameters of
the elliptical cross-sectional profile can be oriented vertically and
horizontally,
respectively. However, this elliptical cross-sectional profile typically
twists or rotates
along the length of the coil spring. Thus, in another part of the coil spring
the long
and short diameters of the elliptical cross-sectional profile can be oriented
horizontally and vertically, respectively. This nonuniformity in the cross-
sectional
profile of the coil spring can result in nonuniform electrical contact with
wafer 1602
and thus nonuniform electroplating.
A coil spring having a uniform cross-sectional profile throughout its length
can be difficult to produce and cost prohibitive. As such, in accordance with
one
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aspect of the present invention, spring member 1882 is formed from a plurality
of coil
springs to maintain a substantially uniform cross sectional profile. In one
configuration of the present embodiment, when spring member 1882 is disposed
on
top of lip portion 1880a. the applied electric charge is transmitted from lip
portion
1880a throughout the length of spring member 1882. Accordingly, in this
configuration, the plurality of coil springs need not be electrically joined.
However,
as alluded to earlier, in another configuration of the present invention, the
electric
charge can be applied directly to spring member 1882. In this configuration,
the
plurality of coil springs is electrically joined using any convenient method,
such as
soldering, welding, and the like. In the present embodiment, spring member
1882
includes a plurality of coil springs, each coil spring having a length of
about 1 to
about 2 inches. It should be recognized, however, that spring member 1882 can
include any number of coil springs having any length depending on the
particular
application. Moreover, as alluded to earlier, spring member 1882 can include
any
convenient conforming and electrically conducting material.
With reference to Figs. 50 and 51, spring member 1882 can include a spring
holder 5002. In the present exemplary embodiment, when spring member 1882 is a
coil spring, spring holder 5002 is configured as a rod that passes through the
center of
the loops of the coil spring. Spring holder 5002 facilitates the handling of
spring
member 1882, particularly when spring member 1882 includes a plurality of coil
springs. Additionally, spring holder 5002 provides structural support to
reduce
undesired deformation of spring member 1882. In the present exemplary
embodiment, spring holder 5002 is preferably formed from a rigid material
(such as
metal, metal alloy, plastic, and the like). Additionally, spring holder 5002
is
preferably formed from a corrosion resistant material (such as platium,
titanium,
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stainless steel, and the like). Furthermore. spring holder 5002 can be
electrically
conducting or non-conducting.
Conducting member I 880 can be formed from any convenient electrically
conducting and corrosion-resistant material. In the present exemplary
embodiment,
conducting member 1880 is formed from a metal or metal alloy (such as
titanium,
stainless steel, and the like) and coated with corrosion-resistant material
(such as
platinum, gold, and the like).
An electric charge can be applied to conducting member 1880 through
transmission line S 104 and electrode 5102. It should be recognized that
transmission
line 5104 can include any convenient electrically conducting medium. For
example,
transmission line 5104 can include electric wire formed from copper, aluminum,
gold,
and the like. Additionally, transmission line 5104 can be connected to power
supplies
1640, 1642 and 1644 (Fig. 16) using any convenient method. For example, as
depicted in Fig. 18A, transmission line 5104 can be run through top section
1858 and
1 S along the top surface of top section 1858.
Electrode S 102 is preferably configured to be compliant. Accordingly, when
pressure is applied to hold bottom section 1856 and top section 1858 together,
electrode 5102 conforms to maintain electric contact with conducting member
1880.
In this regard, electrode 5102 can include a leaf spring assembly, a coil
spring
assembly, and the like. Electrode 5102 can be formed from any convenient
electrically conducting material (such as any metal, metal alloy, and the
like). In the
present exemplary embodiment, electrode 5102 is formed from anti-corrosive
material
(such as titanium, stainless steel, and the like). Additionally, any number of
electrodes 5102 can be disposed around top section 1858 to apply an electric
charge to
conducting member 1880. In the present exemplary embodiment, four electrodes
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5102 are disposed approximately equally spaced at an interval of about 90
degrees
around top section 1858.
As described above, to electroplate a metal layer, wafer 1602 is immersed in
an electrolyte solution and an electric charge is applied to wafer 1602. When
wafer
5 1602 is electrically charged with a potential greater than electrodes 1632,
1634 and
1636 (Fig. 16), metal ions within the electrolyte solution migrate to the
surface of
wafer 1602 to form a metal layer. However, when the electric charge is
applied,
shorting can result if spring member 1882 and/or conducting member 1880 are
exposed to the electrolyte solution. Additionally, during an electroplating
process
when wafer 1602 includes a seed layer of metal. the metal seed layer can act
as an
anode and spring member 1882 can act as a cathode. As such, a metal layer can
form
on spring member 1882 and the seed layer on wafer 1602 can be electropolished
(i.e.,
removed). The shorting of spring member 1882 and the removal of the seed layer
on
wafer 1602 can reduce the uniformity of the metal layer formed on wafer 1602.
Thus, in accordance with various aspects of the present invention, seal
member 1884 isolates spring member 1882 and conducting member 1880 from the
electrolyte solution. Seal member 1884 is preferably formed from anti-
corrosive
material, such as Viton (fluorocarbon) rubber, silicone rubber, and the like.
Also,
although in the present exemplary embodiment depicted in Fig. 51, seal member
1884
includes an L-shaped profile, it should be recognized that seal member 1884
can
include various shapes and configurations depending on the particular
application.
Some examples of the various configurations of seal member 1884 are depicted
in
Figs. 53A to 53G. However, it should be recognized that the various
configurations
depicted in Figs. 53A to 53G are only exemplary and not intended to show each
and
every possible alternative configuration of seal member 1884.
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As describe above and as depicted in Fig. 51, spring member 1882 and seat
member 1884 contact wafer 1602 around the outer perimeter of wafer 1602. More
particularly, spring member 1882 and seal member 1884 contact a width 5106 of
the
outer perimeter of wafer 1602. In general, this area of wafer 1602 cannot be
used to
S later form microelectronic structure and the like. As such, in accordance
with one
aspect of the present invention, width S 106 is maintained at a small ratio of
the overall
surface area of wafer 1602. For example, for about a 300 millimeter (mm)
wafer,
width 5106 is kept between about 2 mm to about 6 mm. It should be recognized,
however, that width S I 06 can be any ratio of the overall surface area of
wafer 1602
depending on the particular application. For example, in one application, the
amount
of metal layer deposited on wafer 1602 can be more important than the usable
area of
wafer 1602. As such, a large portion of the surface area of wafer 1602 can be
dedicated to contacting spring member 1882 and sealing member 1884 to receive
a
large applied charge.
With reference now to Fig. 54, the processing steps performed by wafer chuck
1604 (Fig. 51) are set forth in a flow chart format. With reference to Fig.
51, wafer
chuck 1604 is opened (Fig. 54, block 5402) to receive a wafer 1602 to be
processed.
More particularly, bottom section 1856 can be lowered relative to top section
1858.
Alternatively, top section 1858 can be raised relative to bottom section 1856.
As
alluded to earlier, various methods can be used to open wafer chuck 1604, such
as
pneumatics, springs, vacuum, magnetics, and the like.
If wafer chuck 1604 is empty (Fig. 54, YES branch on Decision Block 5404 to
Block 5408), then a new wafer 1602, which is to be processed, is provided or
inserted
(Fig. 54, block 5408). However, if wafer chuck 1604 contains a wafer, which
has
been previously processed, then the previously processed wafer is removed from
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WO 00/33356 PCT/US99/28106
wafer chuck 1604 (Fig. 54, NO branch on Decision Block 5404 to Block 5406),
then
the new wafer 1602 is provided (Fig. 54, block 5408. As described above, the
handling of wafer 1602 can be performed by a robot 106 (Fig. 16). Also, wafer
1602
can be obtained from a wafer cassette 116 (Fig. 3) and returned to wafer
cassette 116
(Fig.3).
After wafer 1602 is provided within wafer chuck 1604, wafer chuck 1604 can
be closed (Fig. 54, block 5410). As alluded to above, bottom section 1856 can
be
raised relative to top section 1858. Alternatively, top section 1858 can be
lowered
relative to bottom section 1856. As described above, when wafer chuck 1604 is
closed, spring member 1882 forms an electrical contact with wafer 1602 and
conducting member 1880. Additionally, conducting member 1880 forms an
electrical
contact with electrode 502.
After wafer chuck 1604 is closed, wafer chuck 1604 is lowered (Fig. 54, block
5412) within electrolyte solution receptacle 1608 (Fig. 16). As described
above,
wafer 1602 is then immersed in an electrolyte solution. Also, as described
above, seal
member 1884 prevents the electrolyte solution from coming into contact with
spring
member 1882 and conducting member 1880.
When wafer 1602 is immersed in the electrolyte solution, an electric charge is
applied to wafer 1602 (Fig. 54, block 5414). More particularly, in the present
exemplary embodiment, an electric charge is applied to wafer 1602 through
transmission line 504, conductor 502, conducting member 1880, and spring
member
1882. As described above, spring member 1882 forms a plurality of contact
points
around the outer perimeter of wafer 1602 to facilitate a more even
distribution of the
electric charge applied to wafer 1602. Additionally, as described above,
spring
member 1882 forms a plurality of contact points with conducting member 1880 to
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facilitate a more even distribution of the electric charge applied to spring
member
1882. It should be recognized that the electric charge can be applied either
before or
after wafer chuck 1602 is lowered into electrolyte solution receptacle 1608
(Fig. 16).
As alluded to earlier, wafer chuck 1604 can be rotated to facilitate a more
even
electroplating of the metal layer on wafer 1602 (Fig. 16). As depicted in Fig.
16, in
the present exemplary embodiment, wafer chuck 1604 can be rotated about the z-
axis.
Additionally, wafer chuck 1604 can be oscillated in the x-y plane.
With reference again to Fig. 51, after wafer 1602 has been electroplated
and/or
electropolished. wafer chuck 1604 can then be raised (Fig. 54, block 5416)
from
electrolyte solution receptacle 1608 (Fig. 16). In accordance with another
aspect of
the present invention, a dry gas (such as argon, nitrogen, and the like) is
applied to
remove residual electrolyte solution. More particularly, with reference to
Fig. 52A,
the dry gas is applied through nozzle 5202 to remove residual electrolyte from
the
joint between seal member 1884 and wafer 1602. It should be recognized that
any
number of nozzles 5202 can be used depending on the particular application.
Additionally, wafer chuck 1604 can be rotated while the dry gas is applied
through
nozzle 5202. As such, nozzle 5202 can be fixed or moveable.
After wafer chuck 1604 has been raised, wafer chuck 1604 is opened (Fig. 54,
block 5402). The processed wafer is then removed (Fig. 54, NO branch on
Decision
Block 5404 to Block 5406). A dry gas (such as argon, nitrogen, and the like)
can be
applied to remove residual electrolyte solution. More particularly, with
reference to
Fig. 52B, the dry gas is applied through nozzle 5204 to remove residual
electrolyte
from conducting member 1880, spring member 1882, and seal member 1884.
Additionally, wafer chuck 1604 can be rotated while the dry gas is applied
through
nozzle 5204. As such, nozzle 5204 can be fixed or moveable.
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After a new wafer is provided (Fig. 54, block 5408), the entire process can be
repeated. It should be recognized, however, that various modifications can be
made
to the steps depicted in Fig. 54 without deviating from the spirit and scope
of the
present invention.
In the following description and associated drawing figures, various
alternative embodiments in accordance with various aspects of the present
invention
will be described and depicted. It should be recognized, however, that these
alternative embodiments are not intended to demonstrate all of the various
modifications, which can be made to the present invention. Rather, these
alternative
embodiments are provided to demonstrate only some of the many modifications,
which are possible without deviating from the spirit and/or scope of the
present
invention.
With reference now to Fig. 55, in an alternative exemplary embodiment of the
present invention, a wafer chuck 5500 according to various aspects of the
present
invention includes a purge line 5506, a nozzle 5508 and a nozzle 5510. In the
present
exemplary embodiment, purge line 5506 and nozzles 5508 and 5510 inject a dry
gas
(such as argon, nitrogen, and the like) onto spring member 5514 and seal
member
5504. In this manner, after wafer 1602 is processed, residual electrolyte can
be
purged from spring member 5514 and seal member 5504. As described above,
maintaining spring member 5514 free of electrolyte solution facilitates a more
uniform electroplating process. Additionally, purging electrolyte solution
from seal
member 5504 facilitates a better seal when the next wafer is processed. As
depicted
in Fig. 55, in the present exemplary embodiment, purge line 5506 and nozzles
5508
and 5510 are formed in conducting member 5502. Additionally, purge line 5506
can
be connected to pressure line 1852 (Fig. 18A). It should be recognized,
however, that
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wafer chuck 500 can be suitably configured with purge line 5506 and nozzles
5508
and 5510 in a variety of manners without deviating from the spirit and/or
scope of the
present invention. Furthermore, it should be recognized that any number of
purge
lines 5506, nozzles 5508 and nozzles 5~ 10 can be formed in wafer chuck 5500.
S With reference now to Fig. 56, in another alternative exemplary embodiment
of the present invention, a wafer chuck 5600 according to various aspects of
the
present invention includes a purge line 5602 and a plurality of nozzles 5604.
In the
present exemplary embodiment, purge line 5602 and plurality of nozzles 5604
inject a
dry gas (such as argon, nitrogen, and the like) onto seal member 5606. In this
manner, after wafer 1602 is processed and removed from wafer chuck 5600,
residual
electrolyte can be purged from the top of seal member 5606. As depicted in
Fig. 56,
in the present exemplary embodiment, purge line 5602 and plurality of nozzles
5604
are formed in top section 5608. It should be recognized, however, that wafer
chuck
5600 can be suitably configured in a variety manner with purge line 5602 and
plurality of nozzles 5604 without deviating from the spirit and/or scope of
the present
invention. Furthermore, it should be recognized that any number of purge lines
5602
and nozzles 5604 can be formed in wafer chuck 5600.
With reference now to Fig. 57, in still another alternative exemplary
embodiment of the present invention, a wafer chuck 5700 according to various
aspects of the present invention includes a purge line 5702 and a plurality of
nozzles
5704 and 5710. In the present exemplary embodiment, purge line 5702 and
plurality
of nozzles 5704 and 5710 inject a dry gas (such as argon, nitrogen, and the
like) onto
seal member 5706 and spring member 5712, respectively. In this manner, after
wafer
1602 is processed and removed from wafer chuck 5700, residual electrolyte can
be
purged from the tops of seal member 5706 and spring member 5712. As depicted
in
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Fig. 57, in the present exemplary embodiment, purge line 5702 and plurality of
nozzles 5704 and 5710 are formed in top section 5708. It should be recognized,
however, that wafer chuck 5700 can be suitably configured in a variety of
manners
with purge line 5702 and plurality of nozzles 5704 and 5710 without deviating
from
the spirit and/or scope of the present invention. Furthermore, it should be
recognized
that any number of purge lines 5702 and nozzles 5704 and 5710 can be formed in
wafer chuck 5700.
With reference now to Fig. 58, in yet another alternative exemplary
embodiment of the present invention, a wafer chuck 5800 according to various
aspects of the present invention includes a purge line X802 and a plurality of
seal rings
5804 and 5806. In the present exemplary embodiment, seal ring 5806 forms a
seal
between conducting member 5808 and bottom section 5810. Similarly seal ring
5804
forms a seal between conducting member 5808 and top section 5812. As a result,
by
feeding positive pressure gas into purge line 5802 and checking for leakage,
the seal
quality between wafer 1602 and seal member 5814 can be checked. Alternatively,
purge line 5802 can be pumped to generate negative pressure to check the seal
quality
between wafer 1602 and seal member 5814. If this latter process is used, to
prevent
electrolyte from being sucked into purge line 5802, the pumping of purge line
5802
should cease after processing of wafer 1602, then positive pressure should be
injected
through purge line 5802 prior to removing wafer 1602. After wafer 1602 is
processed
and removed from wafer chuck 1200, by injecting a dry gas (such as argon,
nitrogen,
and the like) through purge line 5802, residual electrolyte can be purged from
spring
member 5816 and seal member 5814.
With reference now to Fig. 59, in still yet another alternative exemplary
embodiment of the present invention, a wafer chuck 5900 according to various
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aspects of the present invention includes a seal member 5902 having a
trapezoidal
shape. When wafer chuck 5900 is rotated after processing of wafer 1602, the
trapezoidal shape of seal member 5902 facilitates the removal of residual
electrolyte
from seal member 5902. In the present exemplary embodiment, angle 5904 of seal
member 5902 can range between about 0 degrees to about 60 degrees, and
preferably
about 20 degrees.
With reference now to Fig. 60, in another alternative exemplary embodiment
of the present invention, a wafer chuck 6000 according to various aspects of
the
present invention includes a purge line 6002. In the present exemplary
embodiment,
purge line 6002 is formed through bottom section 6006 and seal member 6004. By
feeding positive pressure gas through purge line 6002, the seal quality
between wafer
1602 and seal member 6004 can be checked. Alternatively, purge line 6004 can
be
pumped to generate negative pressure to check the seal quality between wafer
1602
and seal member 6004. As noted above, if this latter process is used, to
prevent
electrolyte from being sucked into purge line 6002, the pumping of purge line
6002
should cease after processing of wafer 1602 and positive pressure should be
injected
through purge line 6002 prior to removing wafer 1602
With reference now to Fig. 61, in still another alternative exemplary
embodiment of the present invention, a wafer chuck 6100 according to various
aspects of the present invention includes a purge line 6102, a purge line
6108, and a
plurality of seal rings 6116 and 6104. In the present exemplary embodiment,
seal ring
6116 forms a seal between conducting member 6118 and top section 6110.
Similarly
seal ring 6104 forms a seal between conducting member 6118 and bottom section
6106. As a result, the seal quality between wafer 1602 and seal member 61 I2
can be
checked using purge line 6102 and/or purge line 6108.
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More particularly, in one configuration, the seal quality can be checked by
feeding pressure gas into purge line 6102 and purge line 6108 and checking for
leakage. In another configuration, purge line 6102 and purge line 6108 can be
pumped to generate negative pressure to check the seal quality between wafer
1602
S and seal member 6112. In still another configuration, either purge line 6102
or purge
line 6108 can be fed with pressure while the other is pumped to generate
negative
pressure. When negative pressure is used to check for leakage, to prevent
electrolyte
from being sucked into purge line 6102 and/or purge line 6108, pumping should
cease
after processing of wafer 1602, then positive pressure should be injected
through
purge line 6102 and/or purge line 6108 prior to removing wafer 1602. After
wafer
1602 is processed and removed from wafer chuck 6100, by injecting a dry gas
(such
as argon, nitrogen, and the like) through purge line 6102 and/or purge line
6108,
residual electrolyte can be purged from seal member 6112 and spring member
6114.
With reference now to Fig. 62, in another alternative exemplary embodiment
of the present invention, a wafer chuck 6200 according to various aspects of
the
present invention includes a spring member 6208, a conducting member 6210 and
a
seal member 6206. In the present exemplary embodiment, spring member 6208 and
conducting member 6210 are disposed within seal member 6206. This
configuration
has the advantage that spring member 6208, conducting member 6210, and seal
member 6206 can be pre-assembled.
Wafer chuck 6200 further includes a purge Iine 6214 and a plurality of nozzles
6212 formed through seal member 6214 and conducting member 6210. By feeding
positive pressure gas through purge line 6214, the seal quality between wafer
1602
and seal member 6206 can be checked. Alternatively, purge line 6214 can be
pumped
to generate negative pressure to check the seal quality between wafer 1602 and
seal
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member 6206. As noted above, if this latter process is used, to prevent
electrolyte
from being sucked into purge line 6214, the pumping of purge line 62I4 should
cease
after processing of wafer 1602, then positive pressure should be injected
through
purge line 6214 prior to removing wafer 1602
With reference now to Fig. 63, in still another alternative exemplary
embodiment of the present invention, a wafer chuck 6300 includes a purge line
6302
and a plurality of nozzles 6304. In the present exemplary embodiment, purge
line
6302 and plurality of nozzles 6304 inject a dry gas (such as argon, nitrogen,
and the
Iike) onto seal member 6310, conducting member 6308, and spring member 6306.
In
this manner, after wafer 1602 is processed and removed from wafer chuck 6300,
residual electrolyte can be purged from the tops of seal member 6310,
conducting
member 6308, and spring member 6306. As depicted in Fig. 63, in the present
exemplary embodiment, purge line 6302 and plurality of nozzles 6304 are formed
in
top section 6312. It should be recognized, however, that wafer chuck 6300 can
be
suitably configured in a variety of manners with purge line 6302 and plurality
of
nozzles 6304 without deviating from the spirit and/or scope of the present
invention.
Furthermore, it should be recognized that any number of purge lines 6302 and
nozzles
6304 can be formed in wafer chuck 6300.
With reference now to Fig. 64, in yet another alternative exemplary
embodiment of the present invention, a wafer chuck 6400 includes a seal member
6402. In the present exemplary embodiment, seal member 6402 is formed with a
square interior groove for receiving spring member 6404. This configuration
has the
advantage of more securely receiving spring member 6404. It should be
recognized,
however, seal member 6402 can be formed with a variety of shapes depending on
the
particular application.
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With reference now to Fig. 6S, in still another alternative embodiment of the
present invention, a wafer chuck 6500 according to various aspects of the
present
invention includes a purge line 6502, a purge line 6508, and a seal ring 6506.
In the
present exemplary embodiment, seal ring 6506 forms a seal between bottom
section
S 6504 and top section 6510. As a result, the seal quality between wafer 1602
and seal
member 6S 12 can be checked using purge line 6502 and/or purge line 6508.
More particularly, in one configuration, the seal quality can be checked by
feeding pressure gas into purge line 6502 and purge line 6508 and checking for
leakage. In another configuration, purge line 6502 and purge line 6508 can be
pumped to generate negative pressure to check the seal quality between wafer
1602
and seal member 6S 12. In still another configuration, either purge line 6502
or purge
line 6508 can be fed with pressure while the other is pumped to generate
negative
pressure. When negative pressure is used to check for leakage, to prevent
electrolyte
from being sucked into purge line 6502 and/or purge line 6508, pumping should
cease
1 S after processing of wafer 1602, then positive pressure should be injected
through
purge line 6502 and/or purge line 6508 prior to removing wafer 1602. After
wafer
1602 is processed and removed from wafer chuck 6500, by injecting a dry gas
(such
as argon, nitrogen, and the like) through purge line 6502 and/or purge line
6508,
residual electrolyte can be purged from seal member 6S 12 and spring member 6S
14.
With reference now to Fig. 66, in still yet another alternative exemplary
embodiment of the present invention, a wafer chuck 6600 according to various
aspects of the present invention includes a seal member 6602 having a
trapezoidal
shape. When wafer chuck 6600 is rotated after processing of wafer 1602, the
trapezoidal shape of seal member 6602 facilitates the removal of residual
electrolyte
2S from seal member 6602. In the present exemplary embodiment, angle 6604 of
seal
49.
CA 02352160 2001-05-24
WO 00/33356 PCT/US99/28106
member 6602 can range between about 0 degrees to about 60 degrees, and
preferably
about 20 degrees.
As stated earlier, although the present invention has been described in
conjunction with a number of alternative embodiments illustrated in the
appended
drawing figures, various modifications can be made without departing from the
spirit
and/or scope of the present invention. Therefore, the present invention should
not be
construed as being limited to the specific forms shown in the drawings and
described
above.
50.
