Note: Descriptions are shown in the official language in which they were submitted.
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RFID ANTENNA MODULES AND METHODS OF MAKING
TECHNICAL FIELD
The invention relates to "secure documents" such as electronic passports,
electronic ID cards and
smart cards (data carriers) having RFID (radio frequency identification) chips
or chip modules
(CM) and operating in a "contactless" mode (ISO 14443) including dual
interface (DI, or DIF)
cards which can also operate in contact mode (ISO 7816-2), and more
particularly to improving
coupling between components within the smart card, such as between a module
antenna (MA)
connected with the RFID chip (CM) and a booster antenna (BA) on the card body
(CB) of the
smart card and inductively coupled with the module antenna (MA) and consequent
improvements in the RFID chip (CM) interacting with external RFID readers.
BACKGROUND
For purposes of this discussion, an RFID transponder generally comprises a
substrate, an RFID
chip or chip module (CM) disposed on or in the substrate, and an antenna
disposed on or in the
substrate. The transponder may form the basis of a secure document such as an
electronic
passport, smart card or national ID card, which may also be refeiTed to as
"data carriers".
The RFID chip (CM) may operate solely in a contactless (non-contact) mode
(such as ISO
14443), or may be a dual interface (DI, DIF) chip module (CM) which may
additionally be
operative to function in a contact mode (such as ISO 7816-2) and a contactless
mode. The RFID
chip (CM) may harvest energy from an RF signal supplied by an external RFID
reader device
with which it communicates. The chip module (CM) may be a leadframe-type chip
module or
an epoxy-glass type chip module. The epoxy-glass module can be metallized on
one side
(contact side) or on both sides with through-hole plating to facilitate the
interconnection with the
antenna.
The substrate, which may be referred to as an "inlay substrate" (such as for
electronic passport)
or "card body" (such as for smart card) may comprise one or more layers of
material such as
Polyvinyl Chloride (PVC), Polycarbonate (PC), polyethylene (PE), PET (doped
PE), PET-G
(derivative of PE), TeslinTm, Paper or Cotton/Noil, and the like.
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An antenna, which may be referred to as a "card antenna" (CA), may be mounted
to the inlay
substrate using a sonotrode (ultrasonic tool) and electrically connected with
the chip module
(CM). See, for example US 6,698,089 and US 6,233,818, incorporated by
reference herein. A
typical pattern for a card antenna (CA) is generally rectangular, in the form
of a flat (planar) coil
(spiral) having a number of turns, disposed around the periphery of the
substrate (or relevant
portion thereof). See, for example, US 7,980,477 (2011, Finn).
Rather than directly electrically connecting the REID chip (CM) to a card
antenna (CA), a
module antenna (MA) may be incorporated into an antenna module (AM) comprising
the RFID
chip (CM) and the module antenna (MA). The module antenna (MA) may be quite
small (such
as approximately 15mm x 15mm), in contrast with the card antenna (CA) (such as
approximately
50mm x 80mm). The module antenna (MA) may be inductively coupled rather than
electrically
connected to the card antenna (CA). In such cases, the card antenna (CA) may
be referred to as a
booster antenna (BA). The booster antenna (BA) may comprise a portion disposed
around the
periphery of the card body (CB), and another portion which may comprise a
coupler coil (CC)
disposed at an interior at-ea of the card body (CB) for inductively coupling
with the module
antenna (MA). The terms card antenna (CA) and booster antenna (BA) may be used
interchangeably herein.
US 20120038445 (2012, Finn) discloses a transponder with an antenna module
(AM) having a
chip module (CM) and an antenna (MA); a booster antenna (BA) having outer and
inner antenna
structures (D,E) in the form of flat coils disposed around the periphery of
the card body (CB).
The antenna module (AM) may be positioned so that its antenna (MA) overlaps
only one of the
antenna structures or the second antenna structure, for inductive coupling
thereto.
US 5,084,699 (1992, Trovan) entitled Impedance Matching Coil Assembly For
An
Inductively Coupled Transponder. Attention is directed to Fig. 5. A coil
assembly for use in an
inductively powered transponder includes a primary coil (156) and a secondary
coil (158)
wrapped around the same coil forming ferrite rod (160). The primary coil's
leads (162) are left
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floating while the secondary coil's leads (164) are connected to the
integrated identification
circuit of the transponder.
US 5,955,723 (1999, Siemens) entitled Contactless Chip Card discloses a data
carrier
configuration includes a semiconductor chip. Attention is directed to FIG. 1.
A first conductor
loop (2) is connected to the semiconductor chip (1) and has at least one
winding and a cross-
sectional area with approximately the dimensions of the semiconductor chip. At
least one second
conductor loop (3) has at least one winding, a cross-sectional area with
approximately the
dimensions of the data carrier configuration and a region forming a third loop
(4) with
approximately the dimensions of the first conductor loop (2). The third loop
(4) inductively
couples the first conductor loop (2) and the at least one second conductor
loop (3) to one another.
US 6,378,774 (2002, Toppan) discloses a smart card comprising an IC module and
an antenna
for non-contact transmission. The IC module has both a contact-type function
and a non-contact-
type function. The IC module has a first coupler coil (8), the antenna has a
second coupler coil
(3). The first and second coupler coils are disposed to be closely coupled to
each other, and are
coupled in a non-contact state by transformer coupling. Various ways of
forming the first
coupler coil (8) are shown. For example, in FIG. 14, the first coupler coil
(8) is wound around a
coil frame (17), which is provided around the seal resin (16) of IC chip (6).
US 7,928,918 (2011, Gemalto) entitled Adjusting Resonance Frequency By
Adjusting
Distributed Inter-Turn Capacity discloses a method for adjusting frequency
tuning of a resonant
circuit with turns having a regular spacing generating stray inter-turn
capacity.
US 8,130,166 (2012, Assa Abloy) discloses Coupling Device For Transponder And
Smart Card
With Such Device. Attention is directed to Fig. 6. A
coupling device is formed by a
continuous conductive path having a central section (12) and two extremity
sections (11, 11'),
the central section (12) forming at least a small spiral for inductive
coupling with the transponder
device, the extremities sections (11, 11') forming each one large spiral for
inductive coupling
with the reader device.
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US2010/0176205 (2010, SPS) entitled Chip Card With Dual Communication
Interface.
Attention is directed to FIGURE 4. A card body (22) includes a device (18) for
concentrating
and/or amplifying electromagnetic waves, which can channel the electromagnetic
flow
received, in particular, from a contactless chip card reader toward the coils
of the antenna (13)
of the microelectronic module (11). The device (18) for concentrating and/or
amplifying
electromagnetic waves may consist of a metal sheet disposed in the card body
(22) below the
cavity (23) receiving the microelectronic module (11), or may consist of an
antenna consisting
of at least one coil, disposed in the card body (22) below the cavity (23)
receiving the
microelectronic module (11).
The following patents and publications are referenced, and may be
"incorporated by reference",
herein: CA 2,279,176 (1998, PAV); DE 39 35 364 (1990, ADE); DE 43 11 493
(2000.
Amatech); NL 9100347 (1992, Nedap'); US 5,773,812 (1998, ADE); US 6,008,993
(1999,
ADE); US 6,142,381(2000, Finn et al.); US 6,190,942 (2001, "PAV"); US
6,095,423 (2000,
Siemens); US 6,310,778 (2001, Finn et al.); US 6,406,935 (2002, ASK); US
6,719,206 (2004,
On Track); US 7,320,738 (2008, FCI); US 8,100,337 (2012, -SPS"); US
2008/0283615 (2008,
Finn); US 2008/0308641 (2008, Finn); US 2008/0314990 (2008, Smartrac); US
20090057414;
US 2002/0020903 (2002, ADE); US 20100283690(2010, SPS); US 2011/0163167 (2011,
SPS).
SUMMARY
A winding core (WC) having a tubular body portion (B) and two ends is mounted
by one of its
ends to a module tape (MT), a module antenna (MA) is wound around the winding
core (WC), a
chip (CM) is disposed on the module tape (MT) within the winding core (WC).
Connections
(wb) are made, and glob-top (GT) is applied over the chip (CM), substantially
filling the interior
area of the winding core (WC). The module antenna (MA), winding core (WC) and
chip (CM)
may subsequently be overmolded with a mold mass (MM). The winding core (WC)
may have a
flange (F) at one end.
According to an embodiment of the invention, an antenna module (AM, 200, 400)
for a smart
card (SC) may comprise: a module tape (MT, 202, 402); a chip (CM, 210, 410)
disposed on a
surface of the module tape (MT); and a module antenna (MA. 230, 430) disposed
on the surface
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of the module tape (MT), and connected with the chip (CM); characterized by: a
support
structure (DS, WC, 220, 420) secured to the surface of the module tape (MT),
serving as a
winding core for the module antenna (MA) and as a darn for glob-top (GT)
covering the chip
(CM); wherein the support structure (DS, WC, 220, 420) comprises a tubular
body portion (B)
having two opposite open ends (220a/b, 420a/b), one of which is secured to the
surface of the
module tape (MT), the other of which is a free end. The support structure (WC,
420) may have
a flange (F, 424) disposed around the free end (420a) of the body portion (B).
The module
antenna (MA) may be disposed external to the body portion (B); and the chip
(CM) may be
disposed on the module tape (MT) internal to the body portion (B). At least
one slot (S) may
extending through the body portion (B) to allow corresponding at least one end
of the module
antenna (MA) to pass through the body portion (B) from external the body
portion (B) to internal
the body portion (B). Glob-top may cover at least the chip (CM), within the
support structure.
A mold mass (MM) may cover the chip (CM) the support structure (DS, WC) and
the module
antenna (MA). Contact pads (CP) may be disposed on an opposite surface of the
module tape
(MT) for a contact interface.
A smart card (SC) may comprise the antenna module (AM) disposed in a card body
(CB) having
a booster antenna (BA) having an outer portion disposed around a periphery of
the card body
(CB) and a coupler coil (CC) disposed at an interior area of the card body
(CB); wherein the
antenna module (AM) is disposed at the interior area of the card body (CB) for
inductive
coupling of the module antenna (MA) with the coupler coil (CC). A recess (R)
may be provided
in the card body (CB) for receiving the antenna module (AM). At least a
portion of the coupler
coil (CC) may be embedded in the recess (R).
According to an embodiment of the invention, a method of making an antenna
module (AM)
may comprise: affixing a tubular support structure (DS, WC, 220, 420) having
two opposite open
ends (220a/b, 4I0a/b) on a surface of a module tape (MT, 202, 402); and
winding a wire for a
module antenna (MA) around the tubular support structure (DS, WC). The module
antenna
(MA, 230, 430) may be wound using a flyer winding technique (FIG. 3). Before
winding the
wire around the support structure, a first end of the wire for forming the
module antenna (MA)
may be secured to a first pin; and a first end portion of the wire may be
passed over a first bond
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pad (BP) on the module tape (MT). After winding the wire around the support
structure, a
second end portion of the wire may be passed over a second bond pad (BP) on
the module tape
(MT); and a second end of the wire for forming the module antenna (MA) may be
secured to a
second pin. The first and second end portions may be connected to the first
and second bond
pads.
According to an embodiment of the invention, a method of making an antenna
module (AM,
FIG. 1B, 4E) may comprise: mounting a module antenna (MA) to a module tape
(MT); mounting
and connecting a chip (CM) to the module tape (MT); covering the chip (CM) and
its
connections with resin (GT); characterized by: the chip (CM) and its
connections are covered
with resin (GT) by filling an interior area of the module antenna (MA) with
resin after mounting
the module antenna (MA) and after mounting and connecting the chip (CM).
A smart card (SC) may comprise a card body (CB) and an antenna module (AM).
The card body
(CB) may have a booster antenna (BA) comprising windings disposed around the
periphery of
the card body (CB) and a coupler coil (CC) disposed at an interior area of the
card body (CB).
An antenna module (AM) having a module antenna (MA), may be disposed in a
recess of the
card body (CB), within the interior of the coupler coil (CC), and may be
substantially coplanar
with the coupler coil (CC), so that the module antenna (MA) couples
inductively (transformer
coupling) with the coupler coil (CC).
BRIEF DESCRIPTION OF THE DRAWINGS
Reference will be made in detail to embodiments of the disclosure, non-
limiting examples of
which may be illustrated in the accompanying drawing figures (FIGS). The
figures are generally
diagrams. Some elements in the figures may be exaggerated, others may be
omitted, for
illustrative clarity. Although the invention is generally described in the
context of various
exemplary embodiments, it should be understood that it is not intended to
limit the invention to
these particular embodiments, and individual features of various embodiments
may be combined
with one another. Any text (legends, notes, reference numerals and the like)
appearing on the
drawings are incorporated by reference herein. Some figures may be in the form
of diagrams.
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FIG. 1 is a cross-sectional view of a portion of a dual interface (DI) smart
card (SC), also
showing external "contact" and "contactless" reader devices.
FIGs. 1A and 1B are cross-sectional views of an antenna modules (AM) that may
be used in
the smart card (SC) of FIG. 1, according to some embodiments of the invention.
FIG. 1C is a cross-sectional view of a module antenna (MA) subassembly that
can be used
with some of the antenna modules (AM) disclosed herein, according to the
invention.
FIG. 2 is a cross-sectional view of an antenna module (AM), according to an
embodiment of
the invention.
FIG. 2A is a cross-sectional view of a dam structure (DS) component for the
antenna module
(AM) of FIG. 2.
FIGs. 2B, 2C are plan views of the underside of a module tape (MT) for an
antenna module
(AM), according to some embodiments of the invention.
FIG. 3 is a perspective view and FIG. 3A is a plan view of techniques for
forming the module
antennas (MAs) of antenna modules (AMs), according to some embodiments of the
invention.
FIG. 4 is a cross-sectional view of a winding core WC upon which a module
antenna may be
wound, according to an embodiment of the invention.
FIGs. 4A-4F are cross-sectional views of a technique for forming antenna
modules (AMs),
according to an embodiment of the invention.
FIG. 5 is an exploded cross-sectional view showing an antenna module (AM)
being installed
in a card body (CB) of a smart card (SC).
DETAILED DESCRIPTION
Various embodiments will be described to illustrate teachings of the
invention(s), and should be
construed as illustrative rather than limiting. Any dimensions and materials
or processes set
forth herein should be considered to be approximate and exemplary, unless
otherwise indicated.
In the main hereinafter, transponders in the form of secure documents which
may be smart cards
or national ID cards may be discussed as exemplary of various features and
embodiments of the
invention(s) disclosed herein. As will be evident, many features and
embodiments may be
applicable to (readily incorporated in) other forms of secure documents, such
as electronic
passports. As used herein, any one of the terms "transponder", "smart card",
"data cather", and
the like, may be interpreted to refer to any other of the devices similar
thereto which operate
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under ISO 14443 or similar RFID standard. The following standards are
incorporated in their
entirety by reference herein:
- ISO/IEC 14443 (Identification cards ¨ Contactless integrated circuit
cards ¨ Proximity
cards) is an international standard that defines proximity cards used for
identification, and
the transmission protocols for communicating with it.
- ISO/IEC 7816 is an international standard related to electronic
identification cards with
contacts, especially smart cards.
A typical data carrier described herein may comprise (i) an antenna module
(AM) having an
RFID chip or chip module (CM) and a module antenna (MA), (ii) a card body (CB)
and (iii) a
booster antenna (BA) disposed on the card body (CB) to enhance coupling
between the module
antenna (MA) and the antenna of an external RFID "reader". When "chip module"
is referred to
herein, it should be taken to include "chip", and vice versa, unless
explicitly otherwise stated.
The module antenna (MA) may comprise a coil of wire. conductive traces etched
or printed on a
module tape (MT) substrate for the antenna module (AM), or may be incorporated
directly on the
chip itself.
The booster antenna (BA) may be formed by embedding wire in an inlay substrate
or card body
(CB). However, it should be understood that the antenna may be formed using a
processes other
than by embedding wire in a substrate, such as additive or subtractive
processes such as printed
antenna structures, coil winding techniques (such as disclosed in US
6,295,720), antenna
structures formed on a separate antenna substrate and transferred to the inlay
substrate (or layer
thereof), antenna structures etched (including laser etching) from a
conductive layer on the
substrate, conductive material deposited on the substrate or in channels
formed in the substrate,
or the like. When "inlay substrate" is referred to herein, it should be taken
to include "card
body", and vice versa, as well as any other substrate for a secure document,
unless explicitly
otherwise stated.
The descriptions that follow are mostly in the context of dual interface (DI.
INF) smart cards,
and relate mostly to the contactless operation thereof. Many of the teachings
set forth herein
may be applicable to electronic passports and the like having only a
contactless mode of
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operation. Generally, any dimensions set forth herein are approximate, and
materials set forth
herein are intended to be exemplaiy.
Generally, coupling between the module antenna (MA) and the antenna of an
external RFID
reader may be enhanced by incorporating a booster antenna (BA) on the card
body (CB). In
some respects, a booster antenna (BA) is similar to a card antenna (CA).
However, in contrast
with a card antenna (CA) which is directly electrically connected with the
RFID chip or chip
module (such as in US 7,980,477), the booster antenna (BA) is inductively
coupled with the
module antenna (MA) which may be connected with the RFID chip (CM). Such
inductive
coupling may be more difficult to accomplish than a direct electrical
connection.
The booster antenna BA (and other features) disclosed herein may increase the
effective
operative ("reading") distance between the antenna module AM and an external
contactless
reader with capacitive and inductive coupling. With reading distances
typically on the order of
only a few centimeters, an increase of I cm can represent a significant
improvement.
Dual Interface (DI) Smart Card and Readers
FIG. 1 illustrates a dual interface (DI) smart card SC comprising:
- an RFID chip (or chip module) CM, which may be a dual interface (DI) chip
or chip
module, disposed on an underside of a substrate or module tape MT (or chip
carrier tape,
or metal leadframe.);
- a number (such as six) of contact pads CP for implementing a contact
interface (ISO
7816) on a top side of the module tape MT; and
- a module antenna MA disposed on the underside of the module tape MT,
typically
formed from an etched conductor or wire, in a spiral (coil) pattern.
- The module tape MT supports and effects interconnections between the RFID
chip CM,
contact pads CP and module antenna MA, and may be single-sided, having
metallization
on only one side, or double-sided, having metallization on both sides.
- The RFID chip CM may be connected in any suitable manner, such as flip-
chip
connected or wire bonded to the module tape MT.
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- The RFID chip CM and module antenna MA may be overmolded by a mold mass
MM,
for protecting the CM and MA components, and interconnections.
- As used herein, "chip module" includes one or more bare semiconductor
dice (chips). A
"hybrid" chip module may comprise a chip for contact interface and a chip for
contactless
interface, or the like. Reference is made to US 6,378,774 (2002, Toppan) for
an example
of a DIF chip solution, and to US 2010/0176205 (2010, SPS) for an example of a
two
chip solution wherein one chip performs the contact function and the other
chip performs
the contactless function.
- A ferrite element (film or layer) may be incorporated into the antenna
module AM.
between the contact pads CP and the module antenna MA to reduce attenuating
effects
which may be caused by the conductive contact pads CP.
- Together, the RFID chip CM, chip tape MT, contact pads CP and module
antenna MA
constitute an "antenna module" AM.
The smart card SC further comprises:
- a substrate which for smart cards may be referred to as a "card body" CB.
(For an
electronic passport, the substrate would be an "inlay substrate".)
- a booster antenna BA (or card antenna CA) is shown disposed around (just
within) the
periphery of the card body CB, typically in the form of a rectangular, planar
spiral having
a number of turns.
- As used herein, the term card body CB is intended to embrace any
substrate supporting
the booster antenna BA and receiving the antenna module AM. A recess may be
provided in the card body CB for receiving the antenna module AM.
- The smart card may be referred to as a -data carrier", or "transponder",
or the like.
Some exemplary and/or approximate dimensions, materials and specifications may
be:
- Module Tape (MT): epoxy-based tape, 601.im thick
- Chip Module (CM): NXP SmartMx or Infineon SLE66, or other
- Antenna Module (AM): 15mm x 15mm and 300 m thick
- Module Antenna (MA): several windings of approximately 50 m copper wire.
surrounding the chip module CM.
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- Card Body CB: approximately 54 mm x 86 mm, 8101.tm thick, polycarbonate
(PC). The
card body and its card antenna (CA, or booster antenna BA) are significantly
(such as 20
times) larger than the chip module CM and its module antenna MA.
- Booster Antenna BA: 3-12 turns of 1121im copper, self-bonding wire,
ultrasonically
embedded in the card body CB. Alternatively, the booster antenna BA may
comprise
insulated 80um copper wire, disposed in a spiral pattern approximately 46mm x
76mm
(slightly smaller than the card body CB), pitch of the turns 3001i.m,
exhibiting a resonant
frequency of 13.56 MHz. The optimized self-resonance frequency of the booster
antenna
BA may be approximately 13 ¨ 17 MHz.
o An example of a booster antenna with external sections forming a large
spiral (11,
11') and a central portion forming a small spiral (12) may be found in US
8,130,166 (2012, "Assa Abloy"), incorporated by reference herein. The large
spiral is comparable (or analogous) to the BA in FIG. 1, the small spiral is
comparable to the CC in FIG. I.
o An example of a booster antenna with an antenna coil (4) and a coupler
coil (3)
may be found in US 6,378,774 (2002, "Toppan") incorporated by reference
herein. The antenna coil is comparable (or analogous) to the BA in FIG. 1, the
coupler coil is comparable to the CC in FIG. 1.
o The present invention is not limited to the use of any specific booster
antenna,
rather it is directed to particulars of the antenna module AM and its
manufacture.
To enhance coupling between the module antenna MA and the booster antenna BA,
a material
exhibiting electromagnetic coupling properties, such as ferrite, may be
disposed as a thin film on
surface of the card body CB or may be incorporated or embedded as particles in
the card body,
or both (film and particles), in any desired pattern. The use of ferrite as a
material to enhance
coupling or to shield (prevent) coupling is discussed herein as exemplary of a
material exhibiting
high electromagnetic permeability, often being used in one form or another in
conjunction with
antennas. See, for example, US 5,084,699 (1992, "Trovan").
Additional layers (not shown), such as cover layers, may be laminated to the
card body CB to
complete the construction of the smart card.
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The antenna module (AM) may be disposed in the card body (CB), such as in a
milled recess so
that its module antenna MA overlaps, or is within, is substantially coplanar
with or on another
level from the coupler coil CC. See, for example, US 6,378,774 (2002, Toppan),
incorporated
in its entirety by reference herein.
FIG. 1 further illustrates a contact reader having contacts for interacting
(providing power and
exchanging data) with the chip module CM via the contact pads CP in a contact
mode (ISO
7816), and a contactless reader having an antenna for interacting with the
chip module CM via
the booster antenna BA and the module antenna MA (alternatively via a card
antenna CA) in a
contactless mode (ISO 14443).
An embodiment of an Antenna Module (AM)
FIG. 1A shows an antenna module (AM) 100 having an RFID chip (CM) 110 and a
wound wire
module antenna (MA) 130, both of which may be wire bonded to bond pads (BP)
106 on a lower
surface of a module tape (MT) 102. More particularly,
- an epoxy glass substrate (MT) 102 having a number of contact pads (CP)
104 on its top
(as viewed) surface for making a contact interface with an external reader in
a "contact
mode" of operation, and a number of bond pads (BP) 106 disposed on an opposite
surface
of the module tape (MT) 102;
- The chip (CM) 110 may be mounted to the underside (as viewed) of the
module tape
(MT) 102 with its terminals (CT) 110a, 110b connected such as by conventional
wire
bonding to selected ones of the bond pads (BP) 106 on the underside (as
viewed) of the
module tape (MT) 102. Only two of the wire bond connections 114a and 114b are
shown. for illustrative clarity.
- a module antenna (MA) 130 comprising (for example) several turns of
wire, such as in a
3x6 configuration (3 layers, each layer having 6 turns), and having two ends
130a and
130b. The module antenna 130 may be connected by its ends 130a. 130b such as
be
thermo compression bonding to two of the bond pads (BP) 106 on the underside
of the
module tape (MT) 102, as illustrated.
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o To protect the wire bonds (connections) between the chip terminals CT and
the
bond pads BP, after mounting the module antenna MA to the module tape MT,
and after mounting and connecting the chip CM to the module tape MT (either
before or after mounting the module antenna MA), the interior area of the
module
antenna MA may be filled with resin GT, the module antenna MA acting as a
"darn" to contain the resin GT. See FIG. 1B
o The module antenna MA and its ends, as well as the chip CM and its
connections
(which may already be covered with resin GT) may be overmolded with a mold
mass (MM).
- The aggregate of the elements described above, generally the module
tape (MT) 102,
chip module (CM) 110 and module antenna (MA) 130 may be referred to as an
"antenna
module" (AM) 100.
FIG. 1C illustrates a module antenna (MA), or coil subassembly 130, that can
be used in antenna
modules disclosed herein, such as (but not limited to) the antenna module of
FIG. 1A. A coil of
wire 112 for the module antenna (MA) may be wound, using any suitable coil-
winding tool, and
disposed on a film support layer 132. The module antenna MA may comprise
several turns of
wire, and may be in the form of a ring (cylinder), having an inner diameter
(ID) of approximately
9mm, and an outer diameter (OD) of approximately lOmm.
The film support layer 132 may be nitrile film, 60 lam thick and have overall
outer dimensions of
approximately 10-15mm x 10-15mm, or approximately twice as large (across, in
one dimension)
as the module antenna MA which will be mounted thereto.
A central opening 134 may be
provided through the film 132, generally aligned with the position of the
module antenna MA,
and having a diameter which is nearly as large as the ID of the module antenna
MA. The
opening 134 may be formed by a punching operation. The opening 134 is for
accommodating a
chip CM (such as 110, FIG. 1A) and its wire bonds when the antenna module AM
is assembled.
Two openings 136a and 136b may be provided (in the same punching operation as
the central
opening 134) through the film 132 for accommodating bonding of the antenna
wire ends 112a
and 112b, respectively, to the bond pads BP (106, FIG. 1A) on the module tape
MT (102).
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A release liner 138 may be provided on one side of the film 132, such as the
side opposite the
module antenna MA. The central opening 134 may or may not extend through the
release liner
138, which may be paper, having a thickness of approximately 60 m.
After being mounted to the module tape MT (102), and after the chip CM (110)
is mounted and
connected, the module antenna MA 112 may be filled with resin to protect the
chip CM and its
connections. The module antenna MA may be connected before connecting the chip
CM so as to
avoid damaging the chip CM connections.
Winding the Module Antenna on a Dam Structure
FIG. 2 shows that a dam structure (or simply "dam") DS 220 may be disposed on
the underside
(top, as viewed) of the module tape MT 202, and affixed thereto (such as with
an adhesive).
(The module tape MT 202 is illustrated inverted in contrast with FIGs. 1, 1A,
the contact pads
CP 204 being on the bottom, as viewed, in this figure.)
The dam DS 230, which may be referred to as a "winding core WC" or a "support
structure" or
simply as a "ring", has an elongate tubular body portion B and two opposite
open ends 230a and
230b, and may be cylindrical (as illustrated) or substantially rectangular in
cross-section (or any
other suitable shape). One end 230b of the body portion B is mounted to the
module tape MT,
using a suitable adhesive, the other end 230a is a free end (un-mounted). The
dam DS may be
formed of a plastic material such as Mylar, having a thickness T of
approximately 200pm. The
inner diameter (ID) of the darn DS may be approximately 7mm, the outer
diameter (OD) of the
dam DS may be approximately 8mm.
Although shown as round (cylindrical), the cross-section of the dam DS may be
substantially
rectangular, or other suitable shape (for winding an module antenna MA
thereupon), in which
case "ID" would be inner dimension, and "OD" would be outer dimension of the
body portion B.
A module antenna MA 230 (compare 130) having several layers and turns of self-
bonding wire
may be wound on the dam DS. The darn DS should have a height 'h' which is at
least as high as
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the resulting module antenna MA, such as approximately 350um. The dam DS
may be
impregnated with ferrite to increase the inductance of the module antenna MA.
A fixture (not
shown) may be used to support the DS during winding the module antenna MA. The
resulting
interim product comprising a module antenna MA and dam DS mounted to a module
tape MT,
may be considered to be a subassembly for an antenna module AM. The two ends
a, b (compare
112a, 112b) of the module antenna MA are shown, extending outwardly, to bond
pads BP 206
(compare 106) on the surface of the module tape MT.
An RFID chip CM 210 (compare 110) may be subsequently be mounted to surface of
the module
tape MT, within the interior of the dam DS and wire-bonded from its terminals
CT to bond pads
BP on the underside (top, as viewed in FIG. 2) of the module tape MT. Then,
glob-top potting
compound GT (not shown) may be applied within the interior of the darn DS to
protect the chip
CM and wire bonds, resulting in a substantially complete antenna module AM
200. The RFID
chip CM and module antenna MA may be overmolded by a mold mass MM (not shown,
see
FIG. 1), for protecting the chip CM and module MA components, and respective
interconnections to bond pads BP on the module tape MT, completing the antenna
module AM.
FIG. 2A shows that at least one slot S 232 may be provided through the body
portion B of the
dam DS (winding core WC) to accommodate corresponding at least one end (a, b)
of the module
antenna MA wire (not shown) passing therethrough, inwardly, from external to
the body portion
B to the "interior" space enclosed by the dam DS. One or both ends (a, b) of
the module antenna
MA may extend inwardly, through one or two slots in the body portion B (two
ends can extend
through a single slot, at different levels) so that the ends (a, b) terminate
in an area on the module
tape MT enclosed by the darn DS. The slot(s) S should be sized to (wide
enough) accommodate
the diameter of the antenna wire passing therethrough. Having the ends of the
antenna wire
terminate interior to the darn DS has the advantage that they can be protected
by the same glob-
top GT that protects the chip CM (see FIG. 4E).
Antenna Modules formed on 35mm chip carrier tape
FIG. 2B illustrates a technique for forming one of many module antennas MA on
a winding core
WC on a 35 mm chip carrier tape (module tape MT). The two ends a, b of the
module antenna
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MA wire may extend inward (such as though one or more slots in the winding
core WC), for
bonding to bond pads BP disposed on the module tape MT internal to the winding
core WC.
Alternatively, the winding core WC may be omitted, and the module antenna MA
may be an air-
core coil.
FIG. 2C illustrates a technique for forming one of many module antennas MA on
a winding core
WC on a 35 mm chip carrier tape (module tape MT). The two ends a, b of the
module antenna
MA wire may extend outward for bonding to bond pads BP disposed on the module
tape MT
external to the winding core WC (in the manner shown in FIG. 2).
Alternatively, the winding
core WC may be omitted, and the module antenna MA may be an air-core coil.
illustrates a technique for forming module antennas MA's on winding cores WCs,
for example
on a 35 rnm chip carrier tape (module tape MT). The two ends a, b of the
module antenna MA
wire may extend outward, and are connected to bonding pads BP on the module
tape MT
external the winding core WC. Alternatively, the winding core WC may be
omitted, and the
module antenna may be an air-core coil.
In FIGs. 2B and 2C, a square pad is shown for receiving the chip CM. A number
of smaller
bond pads are shown inside the winding cores WC which are connected internally
to the module
tape to the contact pads CP (not shown) on the face-up side of the module tape
MT, and various
contact terminals of the chip may be wire bonded thereto, followed by glob-top
filling of the
winding core WC to protect the wire bonds. In FIGs. 2B and 2C, some
interconnects are
shown, others may be omitted, for illustrative clarity.
"Flyer" coil winding
FIG. 3 illustrates a plurality (approximately fifteen) of module antennas MA,
such as the type
shown in FIG. 2C (ends extending outward from WC) being wound on winding cores
WC, on a
35mm chip carrier tape (module tape MT). The winding cores WC may be disposed
in two
rows, two winding cores WC conveniently fitting side-by-side across the width
of the 35mm
carrier tape. The 35mm chip carrier tape may advance along a stage, stopping
to have a number
(such as two) of modules antennas MA wound at a time. A plurality (such as
fifteen) of pairs of
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retractable "fixation" pins extend from the stage, adjacent the 35mm carrier
tape, on both sides
thereof, each pair of pins being associated with each of the (fifteen) winding
cores WC. A lesser
number (fewer), such as two, of nozzles may be provided for supplying and
winding the wire for
the module antenna MA around a like number (such as two) of wire cores WC.
Generally, to form a given module antenna MA, the nozzle may first wrap a
first end of the wire
around a first of the pair of pins, securing (anchoring, "fixing") the first
end of the wire to the
first pin. The nozzle then moves towards the winding core WC, a first end
portion of the wire
extending (passing) over (across) a first of two bond pads BP on the module
tape MT. Then the
nozzle "flies" (orbits) around the winding core WC, a number (such as twenty)
of times. winding
the wire around the winding core WC - hence, the nomenclature "flyer- winding
technique.
After completing the designated number (such as twenty) of turns, the nozzle
heads away from
the winding core WC, a second end portion of the wire passing over a second of
the two bond
pads for the module antenna MA, to secure (tie off) the second end of the wire
on the second of
the pair of pins. Then the end portions of the wire passing over the two bond
pads BP for the
module antenna MA may be bonded to the respective bond pads.
It may be convenient to first form a plurality of module antennas MA, before
bonding the end
portions of the module antennas BP. Note in the figure that several /(six)
module antennas MA
have already been formed, with their two end portions extending over bond pads
BP and tied off
to a corresponding pairs of pins. Then, in a subsequent step, the end portions
of the module
antennas MA can be bonded (such as using a theiTriode) to the respective bond
pads BP. After
completing formation of the module antennas MA, residual portions (between the
bond pads BP
and associated pins) of the ends of the wire may be cut, the pins retracted,
and -waste" wire
removed such a with a suction system.
The formation of the module antenna MAs and bonding of their end portions to
respective bond
pads BP may be performed prior to inserting the chip CM onto module tape MT.
By completing
these steps before wire bonding of the chip CM (see, for example, FIG. 4D),
the wire bonds to
the chip CM will not disturbed during bonding of the ends of the module
antenna MA.
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The flyer winding technique illustrated in FIG. 3 is applicable to winding a
module antenna MA
on the dam structure DS of FIGs. 2,2A, as well as on the dam structure WC of
FIG. 4.
The following patent relating to flyer winding are incorporated by reference
herein:
US 5,261,615 (1993, Gustafson); US 5,393,001 (1995, Gustafson); US 5,572,410
(1996,
Gustafson); US 5,606,488 (1997, Gustafson); US 5,649,352 (1997, Gustafson)
FIG. 3A shows some additional detail and/or variation(s) on the technique
described above. A
row of four antenna modules (AMs) being formed are shown disposed along one
side of a 35mm
carrier tape. A plurality of tubular, open-ended support structures (WC, DS)
have been placed
at a corresponding plurality of sites for forming a corresponding plurality of
antenna modules
AMs. A plurality of retractable fixation pins for the wire ends are integrated
into the shuttle
(stage). A pair of these pins (labeled #a, #b) is located adjacent the carrier
tape at each
corresponding site for an antenna modules. An exemplary method of forming a
sequence of
module antennas MAs at sites for antenna modules AMs may comprise some or all
of the
following steps, in generally (but not limited to) the following sequence ...
- The wire may be clamped by a clamping mechanism.
- The wire may then be guided by the nozzle past a first pin la of a first
pair (la, lb) of
retractable fixation pins associated with a first (shown at the right) of the
antenna
modules AMs.
o The winding nozzle may be controlled by an x-y-z servo system (not shown)
- The wire may then be guided past a first opening in the shuttle to a
first of the winding
cores WC associated with the first antenna module AM
o The openings in the shuttle may facilitate disconnection of the wire
during
bonding (occurs later)
- The nozzle then moves (orbits) around the winding core WC, forming a
predetermined
number (such as 20) of turns of wire for the module antenna MA
- The nozzle is then guided outwards, past the edge of the 35mm carrier
tape, passing over
a second opening in the shuttle, to the second lb of the first pair of
retractable pins
associated with the first antenna module
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- Then, rather than tying the wire off on the second pin lb, the nozzle
guides the wire
partially (such as approximately 90 degrees) around the second pin lb towards
a first pin
2a of a next pair of pins (2a, 2b) associated with a next (second from the
right) of the
antenna modules. This partial wrap of the wire may be sufficient to anchor
(secure) the
wire to the pin 2a.
- Then, the nozzle guides the wire around the pin 2a towards the wire core
of the second
(from the right) antenna module, passing over another opening in the shuttle.
- The nozzle then moves (orbits) around the second winding core WC, forming a
predetermined number (such as 20) of turns of wire for the module antenna MA.
- The above steps (nozzle guided outward over an opening in the shuttle to
a second pin of
a pair of retractable pins, to a first pin of a next pair of retractile pins,
wrapping partially
around (securing the wire) and being guided inward over an opening in the
shuttle to a
next winding core, etc.) continues until a last winding core has been wound
with a
module antenna MA. Then the wire can be tied off (by the nozzle) around the
second pin
(4b) of the last pair of retractable pins (4a, 4b).
o In FIG. 3A, the nozzle is shown exiting the third (from the right) winding
core,
headed towards the second of the pair of pins 3a, 3b associated with that
antenna
module site.
- The end portions of the wire passing over respective bond pads BP may
then be bonded,
as described above with respect to FIG. 3.
- In a last step. the wire can be cut. pins retracted. and residual wire
removed.
Single-Flange Windin2 Core
FIG. 4 illustrates a winding core WC 420 upon which a module antenna MA may be
wound.
The winding core WC, which may be referred to as a "support structure", may be
made of a
plastic material, such as glass fiber reinforced PPS (Polyphenylene Sulfide).
As with the darn
structure DS 220, the winding core WC may be in the form of a ring, or tubular
structure. having
a circular or substantially rectangular cross-section, and two opposite open
ends 420a, 420b, one
of which ends will be secured (affixed) to the underside of a module tape MT,
the other of which
is a free end (un-mounted).
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The winding core WC comprises a main body portion B 422, and a flange portion
F 424
extending radially (to the left or right, as viewed) outward from the top (as
viewed) free end of
the body portion B. (This is in contrast with the darn DS 220 in which both
ends are essentially
the same as one another.)
The flange F serves to stiffen the body portion B, and also to constrain
(contain) the windings of
the module antenna MA as it is being wound. By way of analogy, when installed
on the module
tape MT, the flange F serves as one flange of a "bobbin", the surface of the
module tape MT
serves as the second flange of the "bobbin". The module antenna MA will be
wound in a coil
winding area between the two "bobbin" flanges. FIG. 4 shows a portion of the
module tape MT
in phantom (dashed lines), and indicates the coil winding area formed between
the flange F and
the underside surface of the module tape MT. (The module tape MT may be epoxy-
glass,
copper-clad on both sides, etched to form bond pads BP on the underside,
contact pads CP on the
face-up side.)
The winding core WC 420 may have the following dimensions (approximate):
- thickness t of the body portion B =¨ 0.85 mm
- inner diameter 1D of the winding core WC =¨ 6.7 mm
- height hl of coil winding area =¨ 0.250 mm
- height h2 of the flange F 0.100 mm
The coil winding area between the flange F and the surface of the module tape
MT may
accommodate (contain) approximately 20 turns of 112 p.m diameter self-bonding
wire for the
module antenna MA. Wire having other diameters, greater or less than 112pm may
be used for
the module antenna MA.
A process for forming a module antenna MA 430 on the winding core WC, further
forming an
antenna module AM is described with respect to FIGs. 4A = 4F. and generally
comprises:
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- fix WC to MT
- wind MA on WC
- dispense adhesive for the CM
- place CM, cure adhesive (cure self-bonding wire)
- wire bonding (CM and MA to BPs on MT)
- glob top fill interior of WC (covering CM)
- overmold MA, WC, CM
FIG. 4A illustrates a first step, wherein the winding core WC 420 is affixed
to the module tape
MT, such as with an adhesive. The adhesive may be applied to either of the end
420b of the
winding core WC or the surface of the module tape MT. The final thickness of
the adhesive may
be approximately 30 pm. Alternatively, the winding core WC may be affixed to
the module tape
MT without adhesive, such as by spin-welding (a frictional welding technique).
In a production
process, a winding core WC (or simply "ring") may be placed at a plurality of
locations along a
35mm carrier tape in preparation for coil winding (winding of the module
antenna MA on the
winding core WC, or dam DS). This step may be referred to as "ring placement".
Contact pads CPs (compare 104) for a contact interface (with an external
reader) are shown in
on the face-up (bottom, as viewed) surface of the module tape MT, for a dual
interface (DI)
antenna module AM. However, is should be understood that the invention can be
practiced in
the context of an antenna module AM that operates solely in contactless mode,
without such
contact pads CP.
FIG. 4B illustrates the winding core WC affixed (assembled, mounted) to the
module tape MT.
A coil winding area is formed between the flange F and the surface of the
module tape MT. In
this and in subsequent figures, the adhesive is omitted, for illustrative
clarity.
FIG. 4C illustrates a next step, wherein the module antenna MA 430 is wound on
the winding
core WC, around the body portion B, in the coil winding area between the
flange F and the
surface of the module tape MT. This may be done in the manner shown in and
described with
respect to FIG. 3 (using the "flyer" winding technique). Other coil winding
techniques may be
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used to form the coils of the module antenna MA. The ends (a, b) of the module
antenna MA,
extending outward from the winding core WC, may be connected with respective
bond pads BP
in this step. Although not shown, the winding core 420 may have at least one
slot (S),
comparable to the at least one slot (S) shown in FIG. 2B, to allow the ends
(a, b) of the module
antenna MA to extend to bond pads (BP) located the inside of the winding core
WC.
The coils (turns) of wire may not be so neatly arranged, as illustrated.
Nevertheless, the coils
(turns) of wire are constrained within the coil winding area by the flange F
and the surface of the
module tape MT, as shown. The module antenna MA may comprise a total of 20
turns (coils) of
wire in the coil winding area, and two ends (a, b) extending over respective
bond pads BP on the
surface of the module tape MT.
FIG. 4D illustrates a next step of forming the antenna module MA, wherein the
chip CM
(compare 110) is installed in the interior area of the winding core WC. Then,
wire bonds wb
(compare 114a, 114b) may be formed between the terminals (compare 110a, 110b)
of the chip
110 and selected ones of the bond pads BP on the surface of the module tape
MT. The ends (a,
b) of the module antenna MA may also be bonded to the selected ones of the
bond pads BP on
the surface of the module tape MT in this step, if they were not previously
connected.
FIG. 4E illustrates a next step, wherein the interior area of the winding core
WC may be filled
with glob-top potting compound GT, or the like, to protect the chip CM and
wire bonds wb. If
heat is applied to cure the glob-top GT, the heat may also cause sticking
together of the self-
bonding wire forming the turns (coils) of the module antenna MA.
FIG. 4F illustrates a next step, wherein a mold mass MM may be formed (by
overmolding) over
the module antenna MA, the ends (a, b) of the module antenna MA, the winding
core WC, the
glob-top GT (including over the chip CM and wire bonds). The mold mass MM may
extend
over the outer edge (lip) of the flange F. slightly into the coil winding area
(except where there is
wire), which may helping retain the mold mass MM in place. To a lesser extent,
the dam
structure DS (FIG. 2), which is also affixed at one end to the module tape MT,
if used in lieu of
the winding core WC, may also help to support (retain, capture) the mold mass
MM.
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The process of forming a module antenna MA for an antenna module AM described
above may
be contrasted with Toppan '774 which shows (FIG. 14) a coil wound around a
coil frame or core
having flanges mounted around the epoxy resin protecting the die and wire
bonds to the die. For
example, in the technique described above (FIGs. 4A-4F)
- the winding core WC has only one flange (the other "virtual" flange at
the opposite open
end of the support structure being the surface of the module tape MT),
- the tubular support structure (WC, DS) may serve as a darn for containing
later-applied
glob-top GT resin,
- the chip CM may be installed after the module antenna MA is formed upon
the module
tape MT (and the wire bonds to the chip CM also being performed after bonding
the ends
of the module antenna MA)
FIG. 5 (compare FIG. I) illustrates the antenna module AM, which could be the
antenna module
200 of FIG. 2 or the antenna module AM 400 of FIG. 4F, installed in a recess R
in a card body
CB of a smart card SC having a booster antenna BA having an outer portion at
the periphery of
the card body and a coupler coil CC at an interior area of the card body, such
as surrounding the
recess R. At least some (including all) of the turns of wire of the coupler
coil CC may be
embedded in the bottom of the recess R, to enhance the inductive (transformer)
coupling
between the coupler coil CC and the module antenna MA. Channels or a wide
trench for
receiving the turns of wire in the bottom of the recess R may be formed by
laser ablation.
While the invention(s) has/have been described with respect to a limited
number of
embodiments, these should not be construed as limitations on the scope of the
invention(s), but
rather as examples of some of the embodiments. Those skilled in the art may
envision other
possible variations, modifications, and implementations that are also within
the scope of the
invention(s), based on the disclosure(s) set forth herein.
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