Note: Descriptions are shown in the official language in which they were submitted.
CA 02532451 2006-O1-11
WO 2005/026415 PCT/EP2004/009436
Device and method for electrolytically treating electrically insulated
structures
Description:
The present invention relates to a device and to a method for electrolytically
treating electrically conductive structures that are electrically insulated
against
each other on surfaces of strip form work pieces in conveyorized plating
lines.
For manufacturing chip cards (smart cards), price tags or identification tags
for
goods, foil-like plastic is utilized, the electrically conductive structures
required
for the electrical function desired being produced thereon.
Conventional methods utilize for example a copper coated material from which
the desired metal pattern is produced using an etching process. In order to
lower the cost of this method and to permit manufacture of sfiructures finer
than
those that may be achieved with fihe etching process, there is an intention to
produce the metal structures using electrolytic deposition. Such a known
method for manufacturing antenna coils is described in U.S. Patent No.
4,560,445. According to this, the metal structure is produced on a polyolefin
film
using a method sequence involving the following method steps: swelling,
etching, conditioning the plastic material for subsequent adsorption of
catalytically active metal, depositing the catalytically active metal,
printing a
mask in the form of a negative image, accelerating the catalytically active
compounds, electroless and electrolytic metal plating.
Processes for metal plating strips include inter alia electroplating methods.
For
many years, what are termed reel-to-reel processing equipments have been
used for this purpose as conveyorized plating lines, the material being
conveyed therethrough and brought into contact with the processing liquid
during transport. The tapes are electrically contacted for electrolytic metal
deposition. Contacting electrodes serve this purpose. For electrolytic
treatment,
1
CA 02532451 2006-O1-11
WO 2005/026415 PCT/EP2004/009436
it is possible to dispose either the two electrodes, meaning the contacting
electrode and the counter electrode, or the counter electrode only within the
processing liquid in the processing lines.
DE 100 65 643 C2 describes a device for electroplating or for electrolytically
etching conductive strip-form work pieces in which both the contact rollers
serving for establishing electrical contact and the counter electrode are
disposed within the bath. The problem of such arrangements is that the contact
rollers are also metal plated within the bath so that there is a risk that the
metal
deposited onto the contact rollers damages sensitive foils.
For the purpose of avoiding or reducing metal deposits on cathodes within the
electrolyte bath, WO 03/038158 A describes an electroplating equipment for
reinforcing of electroplating structures that have already been configured to
be
conductive on a substrate in a reel-to-reel equipment for strips in which an
anode and a rotating contact roller are located in an electrolyte bath. On its
side
turned toward the substrate, the contact roller is connected to the negative
pole
of a direct current source and on the side turned away therefrom, to the
positive
pole of the current source. This is made possible by segmenting the contact
roller in a manner similar to that of the collector of a direct current motor.
As a
result, the metal deposited onto the contact roller during one revolution of
the
roller during normal operation can be stripped off by changing the potential
toward anodic. A major disadvantage of this method is that the contact rollers
are subject to heavy wear as a result of the permanent alternating operation
of
metal plating and depleting. This is the reason why very complicated and
expensive coatings are to be used.
A basic disadvantage however is that only surfaces that are conductive over
their entire area may be electrolytically treated, structures which are
insulated
against each other and are desirable for producing for example antenna coils
however not.
DE 199 51 325 C2 therefore discloses a device and a method for the
contactless electrolytic treatment of electrically conductive structures thafi
are
CA 02532451 2006-O1-11
WO 2005/026415 PCT/EP2004/009436
electrically insulated against each other on surfaces ofi electrically
insulated foil
material, in which the material is conveyed on a conveying path through a
processing equipment while being contacted with the processing liquid. During
transport, the material is conducted past at least one electrode arrangement,
each consisting of a cathodically polarized electrode and of an anodically
polarized electrode, the cathodically polarized electrode and the anodically
polarized electrode being in turn contacted with the processing liquid. A
current
source causes current to flow through the electrodes and the electrically
conductive structures. The electrodes are thereby shielded from each other in
such a manner that substantially no electric current is allowed to flow
directly
between the two oppositely polarized electrodes. A disadvantage of the method
described is that the layer of metal deposited can only have a reduced coating
thickness since as a result of the electrode arrangement metal is deposited on
the one hand but is also, at least in parts, dissolved again on the other hand
as
the work piece is conducted past the cathodically polarized electrode.
As opposed to the previous electrode arrangements, U.S. Patent No. 6,309,517
describes a plating device for plating the entire surface of planar work
pieces
such as printed circuit boards in which the cathode is contacted outside of
the
electrolyte, metal being allowed to deposit as long as the material is in
contact
with the cathode and the electrolyte. For establishing electrical contact
outside
of the electrolyte cell, contact rollers, brushes or glides are used. The
rollers are
seated toward the electrolytic cell by means of sealing rollers. This device
however is not suited for processing strip form work pieces and insulated
structures.
DE 100 65 649 A1 proposes a device for the electrochemical reel-to-reel
processing of flexible strips having one conductive surface that has a
cathodic
contact roller located outside of the electrolyte. Special anode rollers
around
which the strips are wounded are rotatably disposed within the electrolyte.
The
anode rollers are thereby provided with an ion-permeable, electrically
insulating
layer that keeps the strips spaced a defined and as small a distance as
possible
apart from the anode. It is not possible to treat surfaces having structures
that
are electrically insulated against each other though.
CA 02532451 2006-O1-11
WO 2005/026415 PCT/EP2004/009436
As a result, the known methods do not permit to electrolytically treat
surfaces
with small structures that are electrically insulated against each other and
that
are deposited on an electrically insulated work piece in foil strip form in
strip
processing or conveyorized lines.
The problem underlying the present invention therefore is to avoid the
disadvantages of the known electrolytic processing devices and methods. More
specifically it is an object of the present invention to find a device and a
method
which permit continuous electrolytic treatment of small electrically
conductive
structures that are electrically insulated against each other on surfaces of
electrically insulating foil material. A further object of the present
invention is to
find a method and a device which can be used for manufacturing foil material
equipped with such type conductive structures and employed as a component
of chip cards that serve for example to mark and automatically identify and
distribute goods in distribution stations or as electronic identity cards,
e.g. for
access control. Such type electronic components are to be manufactured on an
ultra large scale at very low cost. Still another object of the present
invention is
to find a method and a device which may be utilized for manufacturing printed
circuit foils in the printed circuit technique and printed circuit foils
having plain
electric circuits such as for toys, in automotive engineering or in
communications electronics.
The present invention provides the device in accordance with claim 1 and the
method in accordance with claim 24. Preferred embodiments of the invention
are recited in the subordinate claims.
It must be noted that, as used in this specification and the appended claims,
the
singular forms "a", "an" and "the" include plural referents unless the content
clearly dictates otherwise and vice versa. Thus, for example, reference to a
plurality of work pieces includes a single work piece, reference to "a
contacting
electrode" includes reference to two or more of such contacting electrodes,
and
reference to "an electrolysis region" includes reference to two or more
4
CA 02532451 2006-O1-11
WO 2005/026415 PCT/EP2004/009436
electrolysis regions. Further reference to a work piece includes a foil strip,
foil
segments or panels and the like.
The method and the device of the invention serve to electrolytically treat
more
specifically small electrically conductive structures that are electrically
insulated
against each other on surfaces of electrically insulating strip form work
pieces,
more specifically of plastic strips (plastic foils) provided with such
conductive
structures. Such type structures have dimensions of a few centimeters e.g., of
2
- 5 cm.
The work pieces can be processed on both sides (surfaces) or on one side only.
In the first case, suited provisions for performing electrolytic treatment are
to be
made on both sides, in the flatter case, on one side only.
The method and the device of the invention may also be used for through
plating or metal plating e.g., holes in the work pieces. Insulated structures
on
one side of the work pieces may for example be contacted with insulated
structures or e.g., semiconductor components such as capacitors or chips,
provided on the other side.
The device of the invention comprises at least one arrangement comprising at
least one contacting electrode for the work piece and at least one
electrolysis
region. In the electrolysis region, at least one counter electrode and the
work
pieces are contacted with the processing liquid. The contacting electrode is
prevented from contacting the processing liquid. The contacting elecfirode and
the electrolysis region are spaced such a small distance apart that small
electrically conductive structures that are electrically insulated against
each
other and are to be processed on the surface of the electrically insulating
foil
strip form work pieces can be electrolytically treated. Within a processing
line,
several such electrode arrangements may be disposed one behind the other in
series. Several such type processing lines may be connected in series.
The spacing (distance) between the contacting electrodes and the electrolysis
region is to be as small as possible considering the size of the insulated
s
CA 02532451 2006-O1-11
WO 2005/026415 PCT/EP2004/009436
structures. In determining the spacing between the electrolysis region and the
contacting electrode, the spacing between the beginning of the electrolysis
region and the site on the contacting electrode that establishes sufficient
contact with the work pieces is essential. This spacing is to be minimized. It
should be chosen so that even electrically conductive structures of for
example
5 cm may still be electrolytically treated with good results.
This arrangement of the contacting electrodes and of the electrolysis region
permits to reliably metal plate even small structures that are electrically
insulated against each other. The smaller the spacing between the contacting
electrodes and the electrolysis regions, the smaller the differences in the
coating thickness between the end areas (as viewed in the direction of
transport) and the central areas of the structures which may be due to the
fact
that the structures are in contact with the contacting electrodes while being
simultaneously in the electrolysis region for only a determined distance of
the
conveying path through the device of the invention. A layer that has the same
thickness in the end areas and in the central area may be achieved when the
spacings between the contacting electrodes in the device are so small that the
structures can always be electrically contacted by at least one contacting
electrode as the work pieces are conducted through the line. This is only
possible if the structures are relatively large or if the spacings between the
contacting electrodes are small. As the object of the invention consists in
metal
plating structures having dimensions of but a few centimeters as uniformly as
practicable, the spacing between the contacting electrodes should not exceed a
few centimeters either.
A particularly advantageous embodiment consists in providing at least two
contacting electrodes, one of them being disposed on one side of a transport
section leading through an electrolysis region and the other one on the other
side of said transport section. In order to achieve the advantage of a very
uniform electrolytic treatment as mentioned, the transport section leading
through the electrolysis region may, in this case, be preferably chosen to be
so
short that the electrically conductive structures are in permanent electrical
contact with one of the contacting electrodes.
6
CA 02532451 2006-O1-11
WO 2005/026415 PCT/EP2004/009436
In principle, a plurality of embodiments for implementing the principles
mentioned herein above is conceivable. A particularly preferred first
embodiment consists in providing at least one processing module containing the
processing liquid and the at least one counter electrode, the work pieces
being
conducted therethrough in a horizontal direction of transport wifihout
direction
change. In this case, the work pieces may be conducted either in a horizontal
or
in a vertical orientation, an inclined orientation being also possible. The
processing modules each comprise at least one passage on the entrance side
and one passage on the exit side thereof for the work pieces to enter the
processing module and to exit said module. In this embodiment, the contacting
electrodes are disposed on the passages. The electrolysis regions are located
in the processing modules. This embodiment permits to achieve a very compact
arrangement of the electrodes and of the electrolysis region that allows
processing of even very small structures. Several such type processing
modules may be disposed in series.
In another, second embodiment there is provided at least one tank containing
the processing liquid and the at least one counter electrode. The conveying
path on which the work pieces are conducted passes through the surface of the
liquid into the tank, within the liquid to the counter electrodes and from
there
exits the tank through the surface of the liquid. In this case, the contacting
electrode is disposed (in immediate proximity) to the surface of the
processing
liquid without contacting the latter. The closer to the surface of the liquid
the
contacting electrodes and the counter electrodes are disposed in this case
(the
contacting electrodes outside of the liquid and the counter electrodes within
the
liquid), the better the possibility to also electrolytically process very
small
structures. Thanks to this arrangement, contacting electrodes may more
specifically be disposed in immediate proximity to the surface of the liquid
at
those sites at which the conveying path traverses the surface of the liquid.
Inasmuch, the considerations made herein above apply. In placing squeezing
rollers or air knives in a substantially upward oriented conveying path above
the
liquid surface level not far from a direction change into the horizontal,
entrained
CA 02532451 2006-O1-11
WO 2005/026415 PCT/EP2004/009436
processing liquid may be stripped off by means of the rollers or the air
knives
and returned to the tank.
However, the contacting electrodes must be spaced a minimum distance apart
firom the surface of the liquid in order to prevent said electrodes from being
brought into contact with the liquid.
To achieve as intensive an electrolytic treatment as possible, the conveying
path in this embodiment may enter the tank through the surface ofi the liquid,
traverse the liquid, exit the tank through the surface while passing through
deviating means such as deviating rollers or cylinders several times.
The minimum size of the insulated structures to be processed is more
specifically determined by the minimum spacing that is to be achieved between
the contacting electrode and the counter electrode. The minimum spacing
depends interalia on the spatial dimensions of the contacting electrodes as
well
as on the distance separating the contacting electrodes from the electrolysis
region. It is therefore advantageous to configure the contacting electrodes as
rollers or as a plurality of reels that are arranged in a closely spaced apart
relationship on an axis, the rollers or reels having a very small diameter so
that
the spacing between the longitudinal axes of the rollers or of the reel
electrodes
and the electrolysis region may be chosen to be very small. Thanks to the
compact arrangement that can thus be achieved, electrolytic treatment of
structures having dimensions on the order of 2 crn or even less may be
achieved.
The attempt of reducing the minimum spacing between the electrodes by using
for example round contacting electrodes that are as small as possible is often
marred by the resulting mechanical instability of the contacting electrodes,
more
specifically when elastic contacting materials are being used. This problem
may
in any case be circumvented by using mechanically stable pinch rollers or
reels
that are disposed so as to fit against the contacting electrodes, thus
stabilizing
them, and at need even pressing them slightly together.
s
CA 02532451 2006-O1-11
WO 2005/026415 PCT/EP2004/009436
Instead of rollers and reels, brushes or electrically conductive, sponge-like
devices that wipe the surface of the work pieces can be used as contacting
electrodes.
The contacting electrodes are pressed by gravity and/or by the application of
a
spring force onto the surface of the work piece.
When adjusting the spacing between the contacting electrode and the surface
of the liquid in the second embodiment, the contacting electrode is not
allowed
to be brought into contact with the processing solution. If the contacting
electrode is for example used as a cathode in an electrolytic metal deposition
process, the contacting electrodes must be protected against undesired
metallization. It has however been found out that the spacing between the
contacting electrodes and the surface of the processing liquid cannot be kept
constant in practice. As a result, difficulties may arise when adjusting this
spacing. These variations in the spacing are due to changes in the surface
level
of the processing liquid in the processing tank, said changes being caused for
example by air being blown into said tank. Further, the liquid surface level
may
be lowered by evaporation or by processing liquid being dragged out of the
tank
by the work pieces conveyed through the processing liquid. On the other hand,
the liquid surface level can also increase when dragged out or replenished
processing liquid is returned to the tank.
To circumvent this problem, it has been found advantageous to insert in the
region of the surface of the liquid between the contacting electrode and the
processing liquid a partition member that allows the work pieces to pass
therethrough but protects the contacting electrode from being wetted by the
processing liquid. In order for the work pieces to be allowed to be conducted
into and out of the processing liquid, this partition member must comprise
passage openings such as slots through which the work pieces may be
conducted. Such a partition member may for example be a suitably shaped
liquid cover plate in which such a slot has been formed. Alternatively, two
cover
plates may be provided, said two cover plates being closely spaced together so
as to form the slot.
CA 02532451 2006-O1-11
WO 2005/026415 PCT/EP2004/009436
The electrode arrangements of the invention may further comprise sealing
members such as sealing walls with sealing lips and/or scrapers for retaining
the liquid in the processing tank. Squeezing rollers may further be present,
said
rollers retaining the liquid, for example when the foil is being removed from
the
liquid, while reliably guiding the work pieces. Such type sealing members may
be provided both at the passages provided in the processing modules in the
first
embodiment of the invention and in the partition members of the second
embodiment. Said sealing means serve to retain as completely as possible the
liquid within the electrolysis region so that no remaining liquid is allowed,
as far
as practicable, to get in touch with the contacting electrodes. Several such
squeezing rollers (sealing rollers) may also be stacked one on top of the
other
so that they mutually seal during rotation.
If it is not possible to reliably prevent the processing liquid from getting
into
contact with the contacting electrodes, processing liquid that has exited the
electrolysis region and reached the contacting electrodes may be removed by
providing continuous or intermittent washing or spraying. In order to
efficiently
rinse the processing liquid off the contacting electrodes, the work pieces may
be
transported in a plane that is for example inclined to the horizontal at an
angle
of at least 5°, of about 70° at most and preferably at about
15°. Rinse liquid
delivered to the contacting electrodes quickly drains off so that efficient
removal
of the processing liquid is made possible. Alternatively, processing liquid
that
has exited the electrolysis regions can also be removed by air jets, using air
knives for example.
If the contacting electrodes are configured to be rollers, the work pieces,
when
they are treated on one side only, can be electrically contacted by means of a
contacting roller and of a confronting current-less roller (supporting
roller).
When a conductive pattern is to be produced on both sides, the contacting
rollers are to be provided on either side of the work pieces.
It is advantageous to configure the contacting electrodes and the counter
electrodes to be elongate and to arrange them in such a manner that they
to
CA 02532451 2006-O1-11
WO 2005/026415 PCT/EP2004/009436
extend over the entire useful width of the work pieces. For this purpose, they
may more specifically be disposed substantially parallel to the conveying
path.
In the case of the second embodiment, the deviating rollers may also be
utilized
for establishing an electrical contact.
Roller-shaped contacting electrodes may preferably be manufactured from an
elastic conductive material. This makes it possible to transfer a very high
current onto the surface of the work pieces on the one hand and to reduce the
spacing between the contacting electrodes and the electrolysis regions on the
other, since the contact faces between the electrodes and the surface of the
work pieces that determine these spacings are not narrow elongate areas as
this is the case with rigid rollers but wide areas instead. Possible elastic
contacting materials are metal/plastic composite materials, more specifically
composite materials formed from an elastic plastic material having a large
amount of electrically conductive fillers. They consist of elastomers as a
binder
such as caoutchouc, silicone or other elastic plastics that are
electrochemically
stable and of an electrically conductive filler. The binders also include
conductive adhesives that will not fully cure as they are being used in the
electronics manufacturing sector. The electrically conductive filler is
admixed to
such type materials during manufacturing. The metal plastic composite is thus
obtained.
The fillers, which are also called inclusion components, preferably consist of
metal in the form of powders, fibers, needles, cylinders, spheres, flakes,
felt and
other forms. The amount of filler relative to the entire contacting material
amounts up to 90 % by weight. As the amount of filler increases, the
elasticity of
the metal plastic composite decreases and the electric conductivity increases.
These two values are adjusted to the application case of concern. All of the
electrochemically stable materials that are also electrically conductive are
suited
for being used as a filter. Current filters are for example titanium, niobium,
platinum, gold, silver, special steel and electrocoal. Platinum plated, silver
plated or gold plated particles, such as spheres made from titanium, copper,
aluminum or glass, may be used for example.
11
CA 02532451 2006-O1-11
WO 2005/026415 PCT/EP2004/009436
As the distance between the counter electrodes and the conveying path for the
work pieces is adjusted to be as small as possible in order to achieve uniform
electrolytic treatment, a metal layer of uniform thickness for example, even
at
high cathodic current density, there is a risk of an electrical short being
created
between the work piece and the counter electrode in the event that these are
brought into undesired contact. In order to reliably avoid this risk, the
counter
electrodes may be provided with an ion-permeable, electrically non-conductive
coating (an insulating layer) that is preferably soft and permeable to liquid.
The
spacing between the counter electrodes and the work piece may thus be
minimized in that the counter electrodes with the insulating coating are
brought
near the surfaces of the work piece so that the coatings get in touch with the
surfaces of the work piece.
In the event that the spacing between the counter electrodes and the conveying
path is adjusted to be so small that the coatings on the counter electrodes
wipe
over the work pieces as they are being conducted past the electrodes, the
coatings can preferably be wedged between the surfaces of the work piece and
of the respective one of the counter electrodes. For this purpose, the
coatings
may project more specifically beyond the gaps formed by the counter electrodes
and the surfaces of the work pieces, be thicker on the side of the cell walls
that
is turned away from the electrolysis region and thus protrude beyond the gap
width and hold tight on the outer sides of.the cell walls.
fn order to prevent processing liquid from exiting the electrolysis region in
the
latter embodiment, lock chambers may further be provided within the
processing module, said chambers being disposed directly before or behind the
electrolysis region as viewed in the direction of transport. As a result,
further
partition walls are provided within the processing module, said walls
separating
the electrolysis region from the lock chambers. Accordingly, the lock chambers
are defined by the partition walls and by the cell walls. In this embodiment,
the
lock chambers may be seated against the outside by means of the sealing walls
having sealing lips described herein above.
12
CA 02532451 2006-O1-11
WO 2005/026415 PCT/EP2004/009436
In order to prevent particularly thin work pieces from warping, the counter
electrodes may for example be rotatably carried with their surface rotating at
the
same speed as the contacting rollers. The counter electrodes and the
contacting electrodes may for example be motor driven with the work pieces
being rolled on the anodes, so that they also serve as conveying members. The
counter electrodes may be configured in different ways. They may be formed as
a plate or as an expanded metal. Various types of counter electrodes may be
combined. In order to prevent depletion of active chemical substances at the
surface of the work pieces, fresh electrolyte may continuously be fed from the
interior of a counter electrode. Therefore, counter electrodes made of
expanded
metal are preferred. This makes it possible to work at high cathodic current
densities without burns occurring during. electrolytic deposition.
In the event of electrolytic metal deposition, the contacting electrode is
cathodically polarized and the counter electrode anodically (anode). Both
soluble and insoluble anodes may be used as counter electrodes. Round flood
anodes or anode rollers made of insoluble metal about which, in the second
embodiment of the invention, the work pieces are being wound and thereby
turned round may for example be used. Flood anodes comprise a hollow space
into which processing liquid may be pumped and out of which the liquid may
then be forced under pressure through openings in the anode shell. The to be
treated surfaces of the work pieces may thus continuously be efficiently
supplied with fresh processing liquid. The dimensions of the anodes are
preferably the same as those of the work pieces.
If the device in accordance with the invention is utilized for electrolytic
metal
deposition in the first embodiment, the anodes e.g., flood anodes, in the
processing liquid may be configured to be elongate and oriented substantially
normal to the work pieces. In a particularly advantageous embodiment, the work
pieces may be conducted past a non-conductive, preferably soft, liquid and ion-
permeable coating provided on the anode without an electrical short being
created. This arrangement is provided in the processing modules mentioned
herein above that may be equipped, in addition to the anodes, with electrolyte
feed and discharge lines. In order to seal the module against leakage of
liquid, it
13
CA 02532451 2006-O1-11
WO 2005/026415 PCT/EP2004/009436
is provided with walls on all sides, said walls being for example provided
with
passage openings, preferably slots, for the work pieces. These walls provided
with slots are disposed on the entrance and on the exit side of the module and
additionally comprise the aforementioned sealing members. The sealing
members prevent greater amounts of electrolyte from escaping from the cell
and thus prevent metal to deposit on the cathodic contacting elements. The
sealing members may for example be sealing walls with seating lips that wipe
over the work pieces without destroying them. The liquid is thus prevented
from
exiting the module. If particularly sensitive foils are to be processed, the
elastic
sealing lips may be combined with sealing rollers. The diameter of all of the
rollers must be kept as small as possible in order to permit processing of the
small conductive insulated structures the length of which ranges between 30
and 4.5 mm and less. The lower limit for the diameter is dictated by the
mechanical stability required for the rollers being pressed against the work
pieces.
In order to reliably provide a particularly compact construction with minimal
spacings between the counter electrodes and the contacting electrodes, the
contacting electrodes and the counter electrodes can be accommodated as
compact units on common carrier frames.
The device in accordance with the invention is preferably a component part of
strip processing fines comprising each at least one first and one second
storage
facility e.g., storage drums, for storing the work pieces. Such type
processing
lines often further comprise conveying members for conveying the work pieces
through the processing line from the at least one first storage facility to
the at
least one second storage facility. Additionally, means for guiding sensitive
work
pieces so that they keep a precise straight course, for example lateral guide
rollers and means for modifying the position of the conveying reels, may be
provided. For this purpose, sensors may be provided along the conveying path,
said sensors continuously registering the position of the outer edge of the
work
pieces and modifying the means for conveying and/or guiding the foil upon
detection of nonpermissible deviations.
14
CA 02532451 2006-O1-11
WO 2005/026415 PCT/EP2004/009436
The device is more specifically suited for depositing metal on thin work
pieces in
strip form such as foils. Such type foils may for example consist of polyester
or
polyolefin and of the derivatives thereof, more specifically of polyethylene
and
polyvinyl chloride (PVC). The foils may have different thicknesses ranging for
example from 15 to 200 pm; PVC foils for example may have a thickness of up
to 200 pm, depending on the application case.
The device as claimed may more specifically be utilized for manufacturing coil
shaped structures on plastic foil material. Such type coil shaped structures
are
used as antennas that are utilized for contactless data transmission on a data
carrier (Smart Cards). Carriers comprising such type antennas may for example
carry an integrated circuit that is electrically wired with the antenna so
that
electric pulses generated in the antenna are sent to the integrated circuit
where
they are stored for example or the data received by means of the antenna are
processed as an electrical signal.
Signal processing permits to convert the data supplied, taking for example
into
consideration other data already stored, the thus obtained data being in turn
stored and/or delivered to the antenna. These data, which are then transmitted
by the antenna, can be received in a receiving antenna so that the data
emitted
may for example be compared to the data received by the antenna on the data
carriers. Such type data carriers may for example be utilized in goods
logistics
and in retail trade e.g., as contactless readable price tags or identification
tags
on goods, further as person related data carriers such as ski passes and
identity cards for access control or as identification means for automotive
vehicles.
Further application fields of the foils provided with the electrically
insulated
metal structures are for example the manufacturing of simple electric circuits
such as for toys or wrist watches, in automotive engineering or in
communications electronics. These materials may further be utilized for active
and passive electromagnetic screening of apparatus or as screening grid
materials for buildings as well as on textiles for clothing.
is
CA 02532451 2006-O1-11
WO 2005/026415 PCT/EP2004/009436
The data carriers can be made from foils such as polyester foils, polyolefin
foils
or polyvinyl chloride foils, on which the electrically isolating structures
have
been electrolytically produced, using the device of the invention. For this
purpose, the foils provided with metallized structures and manufactured using
the device are divided, according to the structure patterns produced thereon
in
multiple printed panels, into discrete foil segments corresponding to the size
of
the respective data carriers. The integrated circuits may then be deposited
onto
the foil segments and the metal structures electrically connected to the
integrated circuit deposited. A bonding process may more specifically be
utilized
for this purpose. The integrated circuits can be deposited nat only in the
form of
a chip that has not yet been provided with a carrier, but may also be
deposited
onto a carrier such as a TAB carrier and placed onto the foil. Once the
integrated circuit has been electrically contacted, the foil segment can be
processed into the finished data carrier, said segment being further laminated
with another foil so as to form a card with the antenna being welded therein.
More specifically, the electrically isolating structures on the data carrier
can be
manufactured in the following manner:
The foil material, which is preferably in strip form and has for example a
thickness ranging from 20 - 50 p and a width of 20 cm, 40 cm or 60 cm, is
provided on a storage drum around which the foil is wound.
At first, the strip is provided with the structure to be produced in that for
example
an activator varnish or an activator paste is printed onto the surface of the
foil.
For this purpose, said varnish or paste may for example contain a noble metal
compound, more specifically a palladium compound, preferably an organic
palladium complex. The varnish or paste moreover contains a binding agent as
well as further current constituents such as solvents, dyes and thixotropic
agents. The varnish or paste are printed preferably by means of a roller onto
the
foil conducted past said roller, more specifically with an ofiFset, a gravure
or a
lithographic printing process. For this purpose, the varnish or paste is
transferred from a reservoir onto a dispenser roller, from the dispenser
roller
onto the printing roller and from there onto the foil. Excess varnish or
excess
16
CA 02532451 2006-O1-11
WO 2005/026415 PCT/EP2004/009436
paste is removed from the dispenser roller and from the printing roller using
suited scrapers. The printing roller may for example be coated with hard
chromium. The foil is pressed against the printing rollers by means of a soft
counter roller ("soft roller") for efficient inking. In a station following
the activator
printing station, the ink printed on the foil is dried. For this purpose, the
strip
form foil material is conveyed through a drying path that is for example
formed
from lR radiators or hot air ductors or that may also comprise UV radiators if
the
binding agent in the activator varnish or the activator paste is to dry
reactively
under the action of UV radiation (preferably without solvent). These drying
apparatus are preferably disposed in a drying fiunnel through which the strip
form material is conveyed. After having passed the drying station, the strip
form
material reaches another strip storage facility that may more specifically be
formed from a drum. On its way from the first storage drum from which the
material is unwound to the second drum on which the material is recollected,
said material is guided and stretched over reefs (reel-to-reel process).
The strip form foil that has been printed with the activator varnish or with
the
activator paste is first electrolessly and then electrolytically metal plated
in order
to form the metal structures.
For this purpose, the foil that has been printed with the activator varnish or
paste is unwound from the storage drum and conducted through various
consecutive processing stations of a processing line, the strip form material
being guided over (deviating) reels and stretched (reel-to-reel method). In
principle, it is also possible to convey the strip form material directly from
the
printing process to the wet-chemical treatment without any further
intermediate
storing of the material.
In a first treafiing step the printed material is transferred into a reductor
that
usually is a strong reducing agent in an aqueous solution such as sodium boron
hydride, an amino borane such as dimethyl amino borane or a hypophosphite.
In the reductor, the oxydated noble metal contained in the varnish or the
paste
is reduced to metallic noble metal, for example to metallic palladium. After
reduction, the strip is fed to a rinsing station where excess reductor is
water
1~
CA 02532451 2006-O1-11
WO 2005/026415 PCT/EP2004/009436
rinsed. A spray sink is preferably utilized for this purpose. Next, a very
thin layer
of copper (of 0.2 - 0.5 pm thick) is electrolessly deposited onto the
activator
structures. Copper deposition onto the structures is initiated by the noble
metal
nuclei formed in the reductor, no copper being deposited onto the non printed
areas. A current bath containing formaldehyde as well as tartrate, ethylene
diamine tetraacetate or tetrakis-(propane-2-ol-yl)-ethylene diamine may be
utilized as the copper bath. After copper plating, the strip form material is
conveyed to a rinsing station in which excess copper bath is stripped off by
spray rinsing with water.
Next, the strip form material is fed to the device of the invention in which
the
now electrically conductive structures are selectively coated with further
copper.
All of the known electrolytic copper plating baths can be used for
electrolytic
copper deposition, for example baths containing pyrophosphate, sulphuric acid,
methane sulfonic acid, amido sulfuric acid or tetrafluoroboric acid. A
particularly
suited bath is a sulfuric acid bath that may contain copper sulfate, sulfuric
acid
and small amounts of chloride as well as additives such as organic sulfur
compounds, polyglycolether compounds and polyvinyl alcohol. The sulfuric acid
bath is preferably operated at a temperature near room temperature at as high
as possible a cathodic current density. If the speed at which the foil strip
is
conveyed through the device of the invention is 1 m/min, a cathodic current
density of for example 10 A/dm~ (active structure surface) could be adjusted
so
that copper be deposited at a rate of about 2 ~rm/min. With a line of about
2.5 -
7.5 m in length, a copper layer of from 5 - 15 pm thick can be deposited in
this
way.
Electric current can be supplied to the foil strip and to the anodes in the
device
in accordance with the invention in the form of direct current or of pulsed
current. The latter is advantageous for producing as high a current density as
possible since a copper layer exhibiting good properties (high surface quality
such as gloss, lack of roughness, uniform coating thickness, good ductility,
electric conductivity) can still be deposited under these conditions. For this
purpose, what is termed reverse pulsed current is preferably utilized, i.e., a
pulsed current that comprises both cathodic and anodic current pulses. In
is
CA 02532451 2006-O1-11
WO 2005/026415 PCT/EP2004/009436
principle, unipolar pulsed current is of course also advantageous. Using
reverse
pulsed current, the pulse heights of the cathodic and anodic current pulses,
the
respective pulse widths and at need the interpulse pauses as well are
optimized
in order to optimize the deposition conditions.
Since electrolytic copper plating is performed using insoluble anodes in the
device of the invention, copper ions cannot be subsequently dissolved by
electrolytically dissolving copper anodes. In order to maintain the
concentration
of copper ions in the deposition solution, compounds of a redox system, more
specifically Fe2+ and Fe2+ compounds such as FeSO4 and Fe~(S04)3 are
preferably added to the bath. The Fe2+ ions contained in the bath oxidize at
the
insoluble anode to form Fe3+ ions. The Fe3+ ions are transferred to another
tank
containing metallic copper pieces (regenerating tower). In the regenerating
tower, the copper pieces oxidize under the action of the Fe3+ ions to form
Cu2+
and Fe~~ ions. As the two reactions (anodic oxidation of the Fe2+ ions to form
Fe3+ ions and oxidation of the copper pieces to form Cu2+) proceed while
concurrently, the concentration of copper ions in the deposition solution can
be
kept largely constant.
After the foil strip has been passed through the metal plating device of the
invention, the material is again conducted to a spray sink in which excess
deposition solution is rinsed off. Then, the strip material is transferred to
a
device in which it is contacted with a passivation means that is intended to
prevent copper from tarnishing. Prior to winding the strip form foil material
onto
another storage drum, the material is dried in a drying station. For this
purpose,
the apparatus utilized may be similar to those used for drying the activator
varnish or the activator paste.
The work stations utilized for performing the method steps mentioned are
equipped with suited guide and transport reels or rollers as well as with
apparatus for processing the processing liquids such as filter pumps, dosing
stations for chemicals, as well as with heating and cooling systems.
The invention will be explained with reference to the Figs. The Figs. show:
19
CA 02532451 2006-O1-11
WO 2005/026415 PCT/EP2004/009436
Fig. 1 a cross-sectional side view of a horizontal processing line in
accordance
with the present invention in a first embodiment in two variants;
Fig. 2 a cross-sectional side view of a single processing module of a
horizontal
processing line in the first embodiment;
Fig. 3 a cross section of a half of a single processing module of the
horizontal
processing line in accordance with Fig. 1 as viewed in the direction of
transport;
Fig. 4 a cross-sectional side view of a single module of a horizontal
processing
line in accordance with the present invention in a first embodiment in
another variant;
Fig. 5 a cross-sectional side view of a horizontal processing line in
accordance .
with the present invention in a second embodiment;
Fig. 6 a cross section through the horizontal processing line in accordance
with
Fig. 5 in a detailed solution;
Fig. 7 a detail of the horizontal processing fine of Fig. 6;
Fig. 8 a cross-sectional side view of the horizontal processing line in
accordance with the present invention in the second embodiment in
another variant;
Fig. 9 a cross-sectional side view of a modified implementation of the
horizontal
processing line of Fig. 8.
For closer description of the Figs. it is assumed that metal is deposited onto
strip form foils in the devices in accordance with the invention and that
cathodically polarized contact means and anodes employed as counter
electrodes are provided for the purpose. Alternatively, the device can of
course
be utilized for carrying out other cathodic treatment processes as well.
Further,
the device in accordance with the invention may of course also be utilized for
carrying out anodic processes, for example for anodic etching, chromatizing or
anodizing (for example anodic electrolytic oxidation). In this case, the strip
form
foil is anodically polarized. A cathode is utilized as a counter electrode.
In the Figs. described herein after, like numerals have the same meaning.
CA 02532451 2006-O1-11
WO 2005/026415 PCT/EP2004/009436
Fig. 1 illustrates a first embodiment of the device in accordance with the
invention. The size of the device shown in the Fig. may more specifically
approximately match the actual size of the device. This means that the
discrete
modules M in the device have, as viewed in the direction of transport, a
length
of a few centimeters if electricaffy isolating structures respectively having
dimensions on the order of a few centimeters are to be treated. Viewed in the
direction of transport, the length of a single module M may for example be
4.5 cm. The length of the various modules (in this context the reader is
referred
to size L in Fig. 2) depends on the size of the structures on the foil strip
1. The
width of the discrete modules M depends on the width of the foil 1 to be
processed. If for example a foil strip 1 having a width of 60 cm is processed
in
the device, the discrete modules M must also have a width on this order. A,s a
result, the modules M are preferably elongate processing devices that extend
substantially normal to the direction of transport (direction of transport
denoted
by an arrow in Fig. 1 ) over the entire width of the foil 1.
The foil 1 is preferably provided in the form of a strip which is unwound from
a
reel that has not been illustrated herein and which, after having been
conveyed
through the device of the invention, is wrapped around another reel that has
not
been illustrated either (reel-to-reel).
The processing modules M are disposed along the conveying path of the foil 1
leading through the device so that the foil 1 is allowed to be conveyed
through
one module M after the other. The number of modules M depends on the
processing time required in the discrete modules M: if a very thick copper
layer
is for example to be deposited e.g., a layer of 5 pm thick, with the foil
strip 1
being intended to be conveyed at high speed through the device in accordance
with the invention, e.g., at a speed of 2 m/min, about 110 modules M having an
active length of 4.5 cm are needed to be disposed behind each other if copper
is deposited at a cathodic current density of 10 A/dm2 (2 pm Cu/min). The term
"active length" of a module M is to be construed as the length of the region
within the module M in which metal is deposited onto the foil 1 conveyed
therethrough.
21
CA 02532451 2006-O1-11
WO 2005/026415 PCT/EP2004/009436
The device in accordance with the invention illustrated in Fig. 1 consists of
a
collecting tank 12 in which there are disposed three processing modules M. The
collecting tank 12 consists of a tank bottom and of two vertical side walls
extending parallel to the conveying path on which the foil strip 1 is being
conveyed, said walls extending respectively in front of and behind the plane
of
the drawing and parallel to the direction of transport. Walls are also
provided at
the two vertical end sides, said walls being horizontally slotted for allowing
the
foil strip 1 to enter and exit the collecting tank 12. This is shown in Fig. 1
on the
left hand side and on the right hand side respectively of the collecting tank
12.
The foil strip 1 enters the collecting tank 12 through the horizontal slot
provided
in the entrance wall on the left side wall thereof and is conveyed through the
collecting tank 12 in the horizontal direction and in a horizontal
orientation. The
foil strip 1 can be guided normal to the direction of transport so as to be
slightly
inclined relative to the horizontal in order to aid the liquid in flowing off
the
surface of the foil strip 1 over the lateral side border of the strip 1 that
is oriented
parallel to the direction of transport. The foil is conveyed through three
processing modules M that are disposed behind each other in the direction of
transport. After the foil strip 1 is conveyed through the last module M, it
exits the
collecting tank 12 through the horizontal exit slot provided in the exit wall.
The foil strip 1 is advanced within the collecting tank by means of transport
means and is also guided thereby. The transport means may for example be
the contact rollers 6 and the sealing rollers 7 that will be both described in
closer detail herein after if these rollers are motor driven. In addition to
these
rollers, other transport means that have not been illustrated herein may be
provided such as transport wheels that are secured to motor driven axes that
extend over the conveying path substantially normal to the direction of
transport
or transport rollers that are disposed in the same manner. The transport
wheels
on the axes may be distributed over the entire width of the foil strip 1 or
only be
disposed in the border region of the foil strip 1 for example. In order to
guide the
strip 1 so that it is exactly parallel to the direction of transport, the
transport
means may also be slightly deviated from the conveying path or from the
preferred axis direction normal to the direction of transport in order to
ensure
22
CA 02532451 2006-O1-11
WO 2005/026415 PCT/EP2004/009436
level guidance of the strip 1 on a straight line. Sensors that are not shown
in the
Fig. and that continuously detect the precise position of the strip permit to
modify the orientation of the transport and/or guide rollers in order to
permanently keep the foil on the same conveying path.
Processing liquid running off the processing modules M is allowed to
accumulate in the lower part of the collecting tank 12. The liquid level in
the
collecting tank 12 is labeled with reference numeral 15.
The discrete modules M in the device can be configured to be identical or
different. In the present case they are of identical configuration.
Each processing module M comprises a top and a bottom portion that are
respectively disposed above and beneath the plane of transportation of the
foil
strip 1. The walls of the modules M are indicated at 10. These two portions
form
an upper electrolytic cell 2 and a lower electrolytic cell 3 that are filled
with
processing liquid. The two portions are built according to substantially the
same
principle. Both portions comprise anodes 4 that are oriented toward the plane
of
transportation and are disposed parallel to the plane of transportation on
either
side thereof. In the modules M the anodes 4 are secured to the module housing
by means of suited holders 5. On the faces of the anodes 4 located on this
side
as viewed from the plane of transportation, ion-permeable coatings (insulating
layers) 13 are provided for preventing contact between the foil strip 1 and
the
anodes 4. Without the coatings 1~, this could easily happen because the
spacing between the anodes 4 and the foil strip 1 is preferably chosen to be
very small. This small spacing permits to largely prevent non uniform
electrolytic
treatment at different sites on the electrically conductive structures so that
a
relatively high current density can be adjusted.
Within the modules M, there is the processing liquid that is supplied via
electrolyte feed lines 11 to the inner volumes of the two portions of the
modules
M. As a result, the strip 1 located in the modules M and the anodes 4 are
contacted with the processing liquid so that an electric current is allowed to
flow
23
CA 02532451 2006-O1-11
WO 2005/026415 PCT/EP2004/009436
between the anodes 4 and the structures on the strip 1 that are electrically
insulated against each other.
In order to electrically contact the structures that are electrically
insulated
against each other, the foil strip 1 is electrically contacted in accordance
with
the invention outside of the electrolytic cells 2, 3. By electrically
contacting the
strip 1 very close to the region on the strip 1 in which the anodes 4 provide
a
largely homogeneous electrical field (electrolysis region), the structures on
the
foil 1 that are electrically insulated against each other can be electrically
contacted with contact means while they still or already are within the
regions
mentioned. This makes continuous electrolytic treatment possible.
In the case shown in Fig. 1, contact rollers 6 are provided downstream and
upstream of the left module M and contact brushes 14 downstream and
upstream of the right module M, these contact rollers and brushes being
employed as contact means and being oriented substantially normal to the
direction of transport and over the entire width of the conveying path.
The contact rollers 6 can more specifically be metal rollers, for example
rollers
the outer contacting surface of which is made of special steel or of copper or
rollers having an electrically conductive, elastic surface. In the latter
case, the
surFaces of the rollers 6 may for example be provided with an elastic plastic
coating that is rendered electrically conductive by insertion of metallic
particles.
The contact brushes 14 can be fibers made from copper or graphite for example
that are secured on a brush base. The fibers may additionally be electrically
insulated at the fiber shaft.
To allow the current to flow from the contact rollers 6 or contact brushes 7
via
the structures that are electrically insulated against each other and the
processing liquid to the anodes 4, a current source that has not been
illustrated
herein is utilized, the poles of which are connected to the contact rollers 6
or the
contact brushes 14 or to the anodes 4.
24
CA 02532451 2006-O1-11
WO 2005/026415 PCT/EP2004/009436
In the case shown in Fig. 1, the strip 1 is electrically contacted by means of
electric contact rollers 6 or contact brushes 14, with said rollers 6 and
brushes
14 not coming into contact with the processing liquid. For this purpose, the
contact rollers 6 and the contact brushes 14 are located outside of the
regions
of the modules M that contain processing liquid.
Sealing rollers ~ are further provided, said sealing rollers largely
preventing
processing liquid from exiting the inner volume of the modules M and from
reaching the contact rollers 6 or contact brushes 14. For, if the contact
rollers 6
or the contact brushes 14 were to come into contact with the processing
liquid,
metal could be deposited thereon. This is not desirable. The sealing rollers 7
are preferably elastic and are pressed against the surfaces of the foil strip
1. As
a result, they tightly fit against the surfaces of the strip 1. Like the
contact rollers
6 and the contact brushes 14, they are disposed normal to the direction of
transport and distributed over the entire width of the conveying path for the
foil
strip 1.
Furthermore, elastic sealing walls 9 are provided for sealing the module
housing
against exiting liquid. For this purpose, the sealing walls 9 are secured to
the
end walls 10 of the module housing so as to provide a liquid tight sealing,
preferably pressing tangentially against the sealing rollers 7. In the case of
the
sealing rollers 7 being disposed downstream within a module M and of the
sealing walls 9, the latter are attracted toward the sealing rollers 7 by the
rotation of the same due to the mechanical friction and the static pressure of
the
liquid within the electrolytic cell, thus providing efficient sealing of the
module M
against leakage of processing liquid into the liquid free space. By contrast,
in
the case of the sealing rollers 7 and the sealing walls 9 being disposed
upstream, the sealing walls 9 would continuously be lifted from the sealing
rollers 7 by the rotation thereof so that sufficient sealing against leaking
liquid
could not be provided. Therefore, auxiliary sealing rollers 8 are additionally
provided in the entrance region of the modules M, said auxiliary rollers being
preferably configured to have an elastic surface like the sealing rollers 7
and
rolling on the sealing rollers 7. In this case, the sealing walls 9 fit
against the
2s
CA 02532451 2006-O1-11
WO 2005/026415 PCT/EP2004/009436
auxiliary sealing rollers 8 and efficiently seal the module M against leaking
liquid.
On the sides of the modules M that extend parallel to the direction of
transport,
sealing lips (not shown herein) are provided for sealing against leaking
processing liquid. Since there are no contact means for electrically
conductive
structures in this region, efficient sealing is not absolutely necessary,
though.
The top portion of the modules M can be configured to be removable for
introducing the foil into the device. Corresponding holding elements (not
shown)
mounted to the lower portion of the module permit to securely retain the top
module portion during normal operation and to firmly anchor it using e.g.,
readily
releasable wing nuts.
Fiig. 2 shows a cross section of a module M in a collecting tank 12 that is
filled
to the bath surface level 15 with processing liquid that has run off the
surfaces.
The foil strip 1 enters the collecting tank 12 through a horizontal slot in
the one
end wall thereof and first comes into electrical contact with the contact
brushes
14 via both sides of the material. Electric current is supplied to the
electrically
conductive structures on the strip 1 via the brushes 14. The brushes 14 extend
substantially over the entire width of the strip 1 so that all the structures
on the
strip 1 can be supplied with current. It is important that all the structures
be
touched by the brush fibers as they are conducted past the brushes 14. As the
structures extend in the direction of transport, they can be in electrical
contact
with the brushes 14 while being at the same time located within the electrical
field of the anodes 4 in the electrolytic cells 2, 3.
Very close to the brushes 14 and downstream thereof there are provided
sealing rollers 7 that are disposed on either side of the strip 1. Auxiliary
sealing
rollers 8 additionally roll on the sealing rollers 7, sealing walls 9
providing a
tangential seal. The elastic sealing walls 9 are secured to the cell walls 10
of the
module M. Processing liquid is supplied from the collecting tank to the inner
volume of the module M via electrolyte feed lines 11 and pumps and pipelines
26
CA 02532451 2006-O1-11
WO 2005/026415 PCT/EP2004/009436
(not shown). Excess processing liquid is returned to the collecting tank via
electrolyte discharge lines 17 provided in the cell walls 10.
After having been conducted past the seal, the foil strip 1 enters the inner
volume of the module M in which it is exposed to the electrical field of the
anodes 4 disposed above and beneath the plane of transportation. The anodes
4 are made of expanded metal, for example of platinum plated titanium. lon-
permeable coatings 13 are located between the plane of transportation and the
anodes 4, said coatings preventing an electrical short from developing upon
contact of the anodes 4 with the electrically conductive structures.
After the foil strip 1 has been passed through the module M it is conducted
past
another pair of sealing rollers 7 that prevents liquid from exiting the module
M.
Sealing walls 9 that fit tangentially against the sealing rollers 7 and are
secured
to the cell end walls 10 additionally seal the inner volume against liquid
leakage.
Once the strip has passed the sealing rollers 7 it is brought into contact
with
further contact rollers 6. The structures that are electrically insulated
against
each other and can no longer be contacted by the contact brushes 14 as they
are conveyed through the module M are electrically contacted again as a result
thereof.
Fig. 3 is a cross sectional view of a half of the view indicated at "A" in
Fig. 1.
Inasmuch, the reader is referred to the elements mentioned in the description
of
Fig. 1 and labeled with the corresponding reference numerals.
On either side of the foil strip 1 guided here in a horizontal plane of
transportation, anodes 4 that are also horizontally oriented and mounted on
anode holding devices 5 as well as ion-permeable isolations 13 that directly
fit
against the anodes 4 are shown in the module M which, in the sectional view,
is
denoted by the cell walls 10. The anodes 4 and the foil strip 1 define
electrolytic
cells 2, 3.
Further, horizontally mounted sealing rollers 7 may be seen in the front view,
said rollers being mounted on bearings 16 in one of the cell walls 10. A
2~
CA 02532451 2006-O1-11
WO 2005/026415 PCT/EP2004/009436
respective contour of the sealing rollers 7 is covered by the sealing walls 9
and
is therefore shown in a dotted line. The sealing walls 9 extend toward the
plane
of transportation and tangentially fit against the sealing rollers 7. They are
secured to the cell end wall 10 so as to provide a liquid tight seal.
The processing liquid is supplied from the collecting tank 12 to the inner
volume
of the module M via electrolyte feed lines 11 and (not shown) pumps and
pipelines and is allowed to run off via electrolyte discharge lines 17. The
liquid
that has run off accumulates in the sump of the collecting tank 12 (which is
indicated by the bath surface level 15).
Fig. 4 shows another preferred embodiment of a module M in a collecting tank
12. The view corresponds to the view shown in Fig. 2.
As contrasted with the module M shown in Fig. 2, the ion-permeable coating 13
is in direct contact with the passing foil strip 1. The coating 13
concurrently
performs the function of sealing the inner volume of the processing module M
against the contacting electrodes 14. In order to prevent processing liquid
from
directly reaching the contacting electrodes 14 through the coating 13, the
inner
volume of the module M is bounded by additional inner partition walls 24. On
these inner partition walls 24 the coating 13 is secured on the entrance and
on
the exit side so as to be liquid tight. The coating 13 may additionally be
secured
to the cell walls 10 that extend alongside the conveying path. As the work
piece
1 does not extend as far as the outermost region of the inner volume of module
M, this additional fixation is not absolutely necessary.
Via electrolyte feed lines 11 the processing liquid is delivered to the anodes
14
formed from expanded metal, which it traverses before being supplied to the
coatings 13. Since the coatings 13 are formed from sponge-like or liquid
absorbing material, they can become saturated and establish an electrolytic
contact between the anodes 4 and the strip material 1. Excess processing
liquid
can flow back to the collecting tank 12 in a direction transverse to the
direction
of transport.
2s
CA 02532451 2006-O1-11
WO 2005/026415 PCT/EP2004/009436
Since, thanks to the capillary forces and the squeezing, the liquid is
retained
substantially within the isolating material 13 in the entrance and exit region
of
the inner partition walls 24, there is a reduced risk that liquid exits the
module
M. Residual amounts of liquid that can exit the processing module M are
discharged downward via the volume formed by the partition walls 24 and the
cell wall 10 of the module on the entrance and on the exit side through the
electrolyte discharge line 17 into the sump of the collecting tank 12. As a
result
sealing lips 23 suffice to keep the contacting elements 14 largely free of
liquid.
On the exit side (downstream), two sealing lips 23 can be provided on the wall
10 of the processing module M, said sealing lips being secured both to the
inner
and the outer wall surface 10 in order to prevent processing liquid from
exiting
the module M as it is more easy for the processing liquid to exit the module M
there than in the entrance region because of the forward movement of the strip
1. As a result, the spacing provided between the contact brushes 14 (or, in
the
alternative, of the contact rollers 6) and the electrolytic cells 2, 3 is very
small. In
order to prevent the friction resulting from the coating 13 coming into
contact
with the work piece 1 from causing the strip 1 to elongate, transport rollers
25
can be provided before and behind each module M. To regulate the pressure,
more specifically in the lower module cells 3, control valves can be mounted
into the pipelines of the discharge lines 17, said control valves adjusting
the
pressure to be constant within the cells 2, 3 through sensors provided in said
CeIIS 2, 3.
As the insulating layers 13 continuously wipe over the foil strip 1 and
disturb the
diffusion layer on the work piece 1, this implementation variant permits to
adjust
particularly high current densities.
Fig. 5 is a cross sectional side view through a horizontal processing line in
accordance with the present invention in a second embodiment. The processing
line comprises a collecting tank 12 in which there are disposed three
processing
modules M that are identical in construction. The processing modules M are
disposed alongside the conveying path of the foil strip 1 through the device
so
that the foil strip 1 is allowed to be conveyed through one module M after the
other. The discrete processing modules M substantially consist of the contact
29
CA 02532451 2006-O1-11
WO 2005/026415 PCT/EP2004/009436
rollers 6, the anodes 4 comprising an ion-permeable isolation 13, anode
holders
and processing liquid (electrolyte). The processing liquid fills the
collecting
tank 12 to such an extent that the bath surface level 15 lies just underneath
the
contact rollers 6.
5
The rollers 6 are arranged in such a manner that, at the deviating roller 18,
which, like the contact rollers, can be motor driven for assisting in
transport, the
substantially horizontally fed foil strip 1 is conveyed into the first module
M,
being passed in a vertical movement between the contact rollers 6 into the
processing liquid. The two sides of the foil strip 1 are electrically
contacted by
the two contact rollers 6. The anodes 4 are configured to be flood anodes made
of an insoluble metal from the inner volume of which fresh electrolyte is
continuously supplied for the deposition process. The flood anodes convey the
foil strip 1 past the isolation 13 where it is metal plated before being drawn
out
of the electrolyte while being contacted anew at the other contact reels 6
located above the bath surface level 15. After having been turned round by the
other deviating reel 18, the foil strip 1 is conveyed through the second
module
M and, after having been turned round anew by the third deviating reel 18,
conducted through the third module M. After having been conducted past the
third module M, the foil is again turned round by means of a fourth deviating
reel
18 before being finally horizontally led out of the processing line.
Fig. 6 illustrates a cross sectional detailed solution of two modules M of the
horizontal processing line in accordance with Fig. 5, only one half of each
module M being shown.
In this case, the device is characterized by the additional component parts,
namely the partition member 21 with slots and sealing lips 23 (shown in Fig.
7)
and the pinch rollers 22. These component parts serve to protect the contact
rollers 6 from the processing liquid. The pinch rollers 22 serve to increase
the
mechanical stability of the contact rollers 6, which are configured to be
particularly thin. The pinch rollers 22, which fit directly against the
contact rollers
6, can press these together when the rollers 6 are elastic, thus making
certain
that the current is well transmitted even in the case of contact rollers 6
having a
CA 02532451 2006-O1-11
WO 2005/026415 PCT/EP2004/009436
very small diameter. This in turn permits to further reduce the spacing
between
the anode 4. and the contact rollers 6.
In a special embodiment, the pinch rollers 22 can also perform the function of
the counter electrode. For this purpose, the rollers have for example a spiral
coating that is not illustrated in the Fig. and is deposited in the form of
narrow
strips on the conductive anode surface of the roller shaped anodes 4. The
spacings between the spiral helix remain exposed. The coating, which is
deposited like a spring, rolls on the contact rollers 6, pressing them against
the
work pieces 1. Thanks to the spiral shape, the screening effect of the
coating,
which is not or but to a small extent ion-permeable, on the pinch rollers 22
acting as anodes exerts its effect permanently on other sites of the work
pieces
1 and prevents them from being non-uniformly coated. The same effect can be
achieved using ring shaped isolations that are mounted to the anodes so as to
be offset from one module to the other.
In order to protect the contact rollers 6 from being metal plated by splashing
processing liquid, the surface of the liquid is completely covered by a
partition
member 21 comprising a slot serving as a passage opening.
During electrolytic treafiment the foil strip 1 is passed through the
schematically
denoted anode 4 comprising an isolation (not shown herein) in the first module
M, the anode 4 almost touching the contact rollers 6. The foil strip 1 is
supplied
from the inner volume of the anodes 4 through the slot in the partition member
21 directly to the contact rollers 6 without coming into contact with the
processing liquid outside of the anode 4 like in Fig. 5. As a result, the
amount of
entrained processing liquid is minimized. Then, the foil strip 1 is turned
round at
the deviation roller 18 and conveyed into the second module M. It is thereby
electrically contacted again at the contact rollers 6 and introduced through
the
slot in the partition member 21 into the anode 4 for further metallization.
Fig. 7 shows a schematic detail of the detailed solution for module M of the
horizontal processing line of Fig. 6.
31
CA 02532451 2006-O1-11
WO 2005/026415 PCT/EP2004/009436
The foil strip 1 is passed between the contact rollers 6 that are spaced in
close
proximity to the anode 4 and between the sealing lips 23 that are disposed at
the slot of the partition member 21. It can be seen that the partition member
21
is capable of efficiently protecting the contact rollers 6 from the processing
fluid.
The sealing lips 23 thereby prevent undesired liquid leakage as a result of a
varying bath surface level for example.
Fig. 8 illustrates a cross sectional lateral view of the second embodiment of
a
horizontal processing line in accordance with the present invention in another
variant. The processing line consists of a collecting tank 12 having three
different modules M1, M2 and M3 that are each characterized by various anode
and cathode arrangements.
The processing modules are disposed alongside the conveying path of the foil
strip 1 leading through the device so that the foil strip 1 is capable of
passing
sequentially through the discrete modules, starting with module M1. Deviating
reels 18 are disposed before and between the modules.
The foil strip 1 is introduced into the module M1 by means of a deviating reel
18. The module M1 substantially consists of a pivoted anode roller 4 having an
ion-permeable isolation 13, the anode 4 being partially iri~mersed into the
processing liquid. The liquid surface level is indicated at 15. The coating 13
between the anode roller 4 and the foil strip 1 serves for insulation and can
thereby be supplied with processing liquid provided from the inner volume of
the
roller 4. The module M1 further includes a cover cap 20 that protects the
contact roller 6 against being wetted with processing liquid. On this cover
cap
20 there are disposed, upstream of the anode 4 as viewed in the direction of
transport of the foil strip 1, a single first contact roller 6 that is
electrically
insulated against the anode 4, and downstream of said anode 4 a second
contact roller 6 that is electrically insulated against said anode 4. Said
module
M1 is preferably used if the foil strip 1 is to be metal plated on one side
only.
The anode holder 5 and the contact roller 6 are combined into one unit for a
more compact construction.
32
CA 02532451 2006-O1-11
WO 2005/026415 PCT/EP2004/009436
After metal plating has been completed, the foil strip 1 is conveyed out of
the
module M1 and via a deviating reel 18 into the second module M2. The module
M2 comprises an anode arrangement consisting of a pivoted anode roller 4
having an ion-permeable isolation 13 and of a curved anode 4' also having an
ion-permeable isolation 13 that projects out of the liquid surface level 15
and
conforms to the orientation of the foil strip 1. Upstream and downstream of
the
anode arrangement there are located two identical contacting arrangements
that are disposed on the cover cap 20 so as to be electrically insulated
against
the anode 4. These arrangements consist of a contact roller 6 and of a contact
brush 14 located on the opposite side of the contact roller 6.
After the foil strip 1 has been plated on its two sides in module M2, it is
conveyed via a deviating reel 18 into the third module M3. Module M3 is
substantially similar to module M2. Contact rollers 6 are used in lieu of the
contact brushes 14, said contact rollers being mounted on the same supporting
arm as the anode 4" against which they are electrically insulated. The shape
of
the curved anode 4" clearly conforms to that of the rotatable anode 4. This
module M3 constitutes a preferred embodiment if the use of contact brushes is
to be excluded since the contacfi between the anode 4" and the work pieces 1
is
more uniform and longer than at the anode 4', thus resulting in a more uniform
coating. Upon completion of the treatment in the third module M3 the foil
strip 1
is conveyed out of the processing line via a deviating roller 18.
Fig. 9 illustrates a cross sectional side view of a variant of the horizontal
processing line of Fig. 8.
The identical modules M4 and M5 substantially resemble module M3 shown in
Fig. 9, the lower curved anode 4" having been dispensed with. The modules
are suited for use in fihe cases in which the foil strip 1 is to be coated on
both
sides. In the modules M4 and M5, the contact rollers 6 are mounted to an
anode holder 5 so as to be electrically insulated.
The various embodiments described can also be combined in other manners as
those described herein above. The sealing member with the sealing lips 23
33
CA 02532451 2006-O1-11
WO 2005/026415 PCT/EP2004/009436
shown in Fig. 7 may e.g., also be used in the variant shown in Fig. 8 and in
Fig.
9.
It is understood that the examples and embodiments described herein are for
illustrative purpose only and that various modifications and changes in light
thereof as well as combinations of features described in this application will
be
suggested to persons skilled in the art and are to be included within the
disclosure of the described invention and within the scope of the appended
claims. All publications, patents and patent applications cited herein are
hereby
incorporated by reference.
34
CA 02532451 2006-O1-11
WO 2005/026415 PCT/EP2004/009436
Reference numerals:
1 work piece (foil strip)
2 electrolytic cell top
3 electrolytic cell bottom
4 counter electrodes, anodes
5 counter electrode holders, anode
holders
6 contacting electrodes, contacting
rollers
7 sealing rollers
8 auxiliary sealing rollers
9 sealing wall
10 module wall, cell wall
11 electrolyte feed line
12 collecting tank
13 ion-permeable isolation
14 contact brushes
15 bath surface level
16 sealing roller bearing
17 electrolyte discharge line
18 deviating roller
19 bearing surface for the upper anode
holder
20 covercap
21 partition member
22 pinch roller
23 sealing lip
24 inner partition wall
25 drive rollers
M,
M1
-
M5
processing
modules
