U.S. patent number RE40,137 [Application Number 10/734,072] was granted by the patent office on 2008-03-04 for methods for forming integrated circuits within substrates.
This patent grant is currently assigned to Micron Technology, Inc.. Invention is credited to Rickie C. Lake, Mark E. Tuttle.
United States Patent |
RE40,137 |
Tuttle , et al. |
March 4, 2008 |
**Please see images for:
( Certificate of Correction ) ** |
Methods for forming integrated circuits within substrates
Abstract
.[.The invention includes methods for forming integrated
circuits within substrates, and embedded circuits. In one aspect,
the invention includes a method of forming an integrated circuit
within a substrate comprising: a) providing a recess in a
substrate; b) printing an antenna within the recess; and c)
providing an integrated circuit chip and a battery in electrical
connection with the antenna. In another aspect, the invention
includes a method of forming an integrated circuit within a
substrate comprising: a) providing a substrate having a first
recess and a second recess formed therein; b) printing a conductive
film between the first and second recesses and within the first and
second recesses, the conductive film forming electrical
interconnects between and within the first and second recesses; c)
providing a first electrical component within the first recess and
in electrical connection with the electrical interconnets therein;
d) providing a second electrical component within the second recess
and in electrical connection with the electrical interconnects
therein; and e) covering the first electrical component, the second
electrical component and the conductive film with at least one
protective cover. In another aspect, the invention includes an
embedded circuit comprising: a) a substrate having a recess
therein, the recess having a bottom surface and a sidewall surface
joined to the bottom surface; b) interconnect circuitry formed on
the bottom and sidewall surfaces; and c) an integrated circuit chip
within the recess and operatively connected to the interconnect
circuitry..]. .Iadd.Method of forming a radio frequency
identification (RFID) device. In one embodiment, a recess is
provided in a plastic substrate containing an integrated circuit
comprising RFID circuitry. A conductive material extends over a
sidewall of the recess and is coupled to the integrated circuit in
a first region and to an antenna in a second region. A flexible
film may be disposed over the recess, the integrated circuit, and
the conductive material..Iaddend.
Inventors: |
Tuttle; Mark E. (Boise, ID),
Lake; Rickie C. (Meridian, ID) |
Assignee: |
Micron Technology, Inc. (Boise,
ID)
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Family
ID: |
25299818 |
Appl.
No.: |
10/734,072 |
Filed: |
December 10, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
Issue Date |
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Reissue of: |
08847123 |
May 1, 1997 |
06329213 |
Dec 11, 2001 |
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Current U.S.
Class: |
438/19;
257/E21.7; 29/846; 438/126 |
Current CPC
Class: |
G06K
19/07749 (20130101); G06K 19/0775 (20130101); H01L
2924/01078 (20130101); H01L 2924/15153 (20130101); H01L
2924/15165 (20130101); H01L 2224/16225 (20130101); Y10T
29/49155 (20150115) |
Current International
Class: |
H01L
21/00 (20060101) |
Field of
Search: |
;257/E21.7
;438/125,42,64,126,19 ;29/840,852,837,849,846,850 ;264/272.17 |
References Cited
[Referenced By]
U.S. Patent Documents
Foreign Patent Documents
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JP |
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WO 90/07858 |
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WO |
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Other References
Casson, K., et al., "High Temperature Packaging: Flip Chip on
Flexible Laminate", Surface Mount Technology, pp. 19-20 (Jan.
1992). cited by other .
Johnson, R.W., "Polymer Thick Films: Technology and Materials",
Circuits Manufacturing (reprint), 4 pages (Jul. 1982). cited by
other .
Gilleo, K., "Using SM Devices on Flexible Circuitry",
ELECTRI-ONICS, pp. 20-23 (Mar. 1986). cited by other.
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Primary Examiner: Everhart; Caridad
Attorney, Agent or Firm: Wells St. John, P.S.
Claims
What is claimed is:
1. A method of forming a radio frequency communication device
comprising: providing a recess within a substrate; providing at
least a portion of an antenna within the recess; providing an
integrated circuit at least partially within the recess and in
operative electrical connection with the antenna; and wherein the
antenna is a loop antenna which crosses itself at a bypass, said
bypass comprising dielectric material between crossing portions of
the loop antenna.
2. A method of forming an integrated circuit within a substrate
comprising: providing a recess in a substrate; providing
substantially an entirety of an antenna within the recess; and
providing an integrated circuit chip and a battery supported by the
substrate and in operative electrical connection with the
antenna.
3. A method of forming an integrated circuit within a substrate
comprising: providing a recess in a substrate; providing at least a
portion of an antenna within the recess; providing an integrated
circuit chip and a battery supported by the substrate and in
operative electrical connection with the antenna; and wherein the
antenna is provided within the recess and on a portion of the
substrate outside of the recess.
4. The method of claim 3 wherein the antenna comprises a
predominate portion within the recess.
5. The method of claim 3 wherein the antenna comprises a
predominate portion outside of the recess.
6. A method of forming an integrated circuit within a substrate
comprising: providing a recess in a substrate; providing at least a
portion of an antenna within the recess; providing an integrated
circuit chip and a battery supported by the substrate and in
operative electrical connection with the antenna; and wherein the
antenna is a loop antenna which crosses itself at a bypass, said
bypass comprising dielectric material between crossing portions of
the loop antenna.
7. The method of claim 3 wherein at least one of the battery and
the integrated circuit chip are provided at least partially within
the recess.
8. The method of claim 3 wherein the battery is bonded to the
substrate within the recess.
9. The method of claim 3 wherein the step of providing the antenna
comprises printing a conductive film.
10. The method of claim 3 wherein the step of providing the antenna
comprises pad printing a conductive film.
11. A method of forming an integrated circuit within a substrate
comprising: providing a recess in a substrate; providing at least a
portion of a loop antenna within the recess, the loop antenna
comprising a bypass where portions of the antenna cross one
another, the bypass comprising a dielectric material between the
crossing portions of the antenna; and providing an integrated
circuit chip in operative electrical connection with the
antenna.
12. The method of claim 11 wherein the portions of the antenna
which cross one another are substantially perpendicular to one
another.
13. A method of forming an integrated circuit within a substrate
comprising: providing a recess in a substrate; pad printing a
conductive material within the recess to form at least a portion of
a conductive circuit within the recess and to form at least a
portion of an antenna within the recess; placing an integrated
circuit chip within the recess and bonding the integrated circuit
chip to the conductive circuit and the antenna; and placing a
battery within the recess and in electrical connection with the
integrated circuit chip.
14. The method of claim 13 wherein the substrate is a card
configured for carrying on a person.
15. The method of claim 13 further comprising, after the printing,
providing an electroless metal within the recess to selectively
plate the conductive circuit.
16. The method of claim 13 further comprising, after bonding the
chip to the conductive circuit, filling the recess with a liquid
encapsulation material and curing the encapsulation material into a
solid mass.
17. The method of claim 13 further comprising, after bonding the
chip to the conductive circuit, covering the recess with a
protective cover.
18. A method of forming an integrated circuit within a substrate
comprising: providing a substrate having a recess formed therein,
said recess having a bottom surface and a sidewall surface joined
to the bottom surface; pad printing a conductive film within the
recess to form electrical interconnects within the recess and to
form at least a portion of an antenna, the electrical interconnects
extending along the bottom surface and the sidewall surface of the
recess; placing an integrated circuit chip within the recess and in
electrical connection with the electrical interconnects; covering
the integrated circuit and the conductive film within the recess
with a protective cover; and wherein the integrated circuit
comprises radio frequency identification device circuitry, and
further comprising placing a battery within the recess and in
electrical connection with the radio frequency identification
device circuitry through the electrical interconnects.
.Iadd.19. A method of forming a device comprising: providing a
recess within a substrate; providing at least a portion of an
antenna within the recess; providing an integrated circuit at least
partially within the recess and in operative electrical connection
with the antenna; wherein the antenna crosses itself at a bypass,
said bypass comprising dielectric material between crossing
portions of the antenna; and wherein the antenna includes a
connection between the integrated circuit and a first antenna
portion, the first antenna portion extending from at least
partially within the recess to outside the recess, a second
connection between the integrated circuit and a second antenna
portion, the second antenna portion extending from at least
partially within the recess to outside the recess, and a third
antenna portion outside of the recess and coupled to the first and
second antenna portions. .Iaddend.
.Iadd.20. A method comprising: forming a recess in a plastic
substrate, the recess having an approximately planar bottom surface
and four sidewall surfaces that slope outward from the bottom
surface toward an upper surface of the substrate; and subsequently
performing the steps of: providing a monolithic integrated circuit
chip within the recess, the chip comprising RFID circuitry coupled
to first and second antenna ports to provide memory and processing
functions, the first and second antenna ports configured to be
electrically coupled together via an antenna and, subsequent to the
forming of the recess: providing a first conductive layer coupled
to the first antenna port of the chip and extending over at least a
portion of a first of the sidewall surfaces; and providing a second
conductive layer coupled to the second antenna port of the chip and
extending over at least a portion of a second of the sidewall
surfaces..Iaddend.
.Iadd.21. The method of claim 20, wherein providing the first and
second conductive layers comprises printing..Iaddend.
.Iadd.22. The method of claim 20, further comprising forming a
conductive adhesive between the first conductive layer and the
first antenna port and forming a conductive adhesive between the
second conductive layer and the second antenna port..Iaddend.
.Iadd.23. The method of claim 20, further comprising: providing at
least a portion of an antenna over the upper surface of the
substrate and coupling the antenna to the first and second
conductive layers; and providing a flexible plastic film over the
recess, the chip, and the antenna, the flexible plastic film being
bonded to the portion of the antenna..Iaddend.
.Iadd.24. The method of claim 20, further comprising: providing at
least a portion of an antenna formed using a first process over the
upper surface of the substrate; coupling the antenna to the first
and second conductive layers, the first and second conductive
layers having been formed using a second process; and providing a
flexible plastic film over the recess, the chip, and the
antenna..Iaddend.
.Iadd.25. A method comprising: providing a plastic substrate
comprising a plurality of recesses, each of the recesses having a
bottom surface and four sidewall surfaces that extend
non-perpendicularly from the bottom surface toward an upper surface
of the substrate; and subsequently performing the steps of:
disposing a plurality of integrated circuits within the plurality
of recesses such that each of the recesses contains an integrated
circuit, each of the integrated circuits comprising RFID circuitry
coupled to first and second antenna ports to provide memory and
processing functions, the first and second antenna ports configured
to be electrically coupled together via an antenna; and providing a
plurality of continuous conductive films, each of the continuous
conductive films having a first portion and a second portion, the
first portion being coupled to respective ones of the integrated
circuits disposed within the recesses and the second portions
extending above the upper surface of the substrate..Iaddend.
.Iadd.26. The method of claim 25, wherein the substrate comprises a
plurality of rows of recesses and a plurality of columns of
recesses..Iaddend.
.Iadd.27. The method of claim 25, further comprising covering the
plurality of integrated circuits and the plurality of continuous
conductive films with an insulting material initially provided as a
liquid material that is subsequently cured into a non-liquid
material, and wherein each of the continuous conductive films is
disposed over at least one respective sidewall surface between the
first and second portions..Iaddend.
.Iadd.28. The method of claim 25, wherein the continuous conductive
films comprise printed films..Iaddend.
.Iadd.29. The method of claim 25, wherein the first portion of each
of the continuous conductive films is coupled to respective ones of
the integrated circuits using a conductive adhesive..Iaddend.
.Iadd.30. A method comprising: forming a recess in a plastic
substrate, the recess having a bottom surface and four sidewall
surfaces that extend non-perpendicularly from the bottom surface
toward an upper surface of the substrate; and subsequently
performing the steps of: providing an antenna portion disposed
outside of the recess; disposing an integrated circuit within the
recess, the integrated circuit comprising RFID circuitry coupled to
first and second antenna ports to provide memory and processing
functions; disposing a conductive material layer over at least one
of the four sidewall surfaces to couple the integrated circuit to
the antenna portion outside the recess, wherein the antenna portion
is configured to electrically couple the first antenna port to the
second antenna port; and providing a flexible film over the recess,
the integrated circuit, and the conductive material
layer..Iaddend.
.Iadd.31. The method of claim 30, wherein depositing the conductive
material layer comprises printing a film..Iaddend.
.Iadd.32. The method of claim 30, further comprising coupling the
integrated circuit to the conductive material layer using a
conductive adhesive..Iaddend.
.Iadd.33. The method of claim 32, wherein the conductive material
layer is disposed over the bottom surface at a first end and over
the upper surface at a second end..Iaddend.
.Iadd.34. The method of claim 33, further comprising covering the
conductive material layer with an insulating material and bonding
the flexible film directly on at least a portion of the insulating
material..Iaddend.
.Iadd.35. The method of claim 34, wherein the antenna comprises a
material layer that is different from the conductive material
layer..Iaddend.
.Iadd.36. The method of claim 30, further comprising covering the
conductive material layer with an insulating material and bonding
the flexible film over the insulating material..Iaddend.
.Iadd.37. The method of claim 36, wherein covering the conductive
material layer with the insulating material comprises forming the
insulting material directly on the conductive material layer and
over the upper surface of the substrate..Iaddend.
.Iadd.38. The method of claim 37, wherein covering the conductive
material layer with the insulating material includes depositing a
liquid material and curing the liquid material to form the
insulting material..Iaddend.
.Iadd.39. The method of claim 38, wherein depositing the conductive
material layer comprises printing a film..Iaddend.
.Iadd.40. The method of claim 39, wherein the film is less than
about one mil in thickness..Iaddend.
.Iadd.41. A method comprising: providing a plastic substrate
comprising a recess, the recess having a bottom surface and
sidewall surfaces that extend non-perpendicularly from the bottom
surface toward an upper surface of the substrate, each of the
sidewall surfaces sloping outward from the bottom surface toward
the upper surface; providing an antenna, at least a portion of
which is a first conductive film disposed above the upper surface;
providing an integrated circuit within the recess, the integrated
circuit comprising RFID circuitry coupled to first and second
antenna ports to provide memory and processing functions; providing
a second conductive film, separate from the first conductive film,
having a first region coupled to the integrated circuit and a
second region coupled to the portion of the antenna; and disposing
a flexible film above the recess, the antenna, the integrated
circuit, and the second conductive film, and electrically coupling
the first and second antenna ports together via the
antenna..Iaddend.
.Iadd.42. The method of claim 41, wherein the second conductive
film comprises a printed film..Iaddend.
.Iadd.43. The method of claim 41, wherein the first region of the
second conductive film is disposed above the bottom
surface..Iaddend.
.Iadd.44. The method of claim 41, wherein the second conductive
film is disposed above at least one of the sidewall surfaces
between the first and second regions..Iaddend.
.Iadd.45. The method of claim 41, further comprising bonding a
conductive adhesive to the integrated circuit and to the first
region of the first conductive film..Iaddend.
.Iadd.46. The method of claim 41, further comprising covering the
second conductive film with an insulating material and disposing
the flexible film over the insulating material..Iaddend.
.Iadd.47. The method of claim 41, wherein at least one of the
sidewall surfaces slopes in at least a generally linear manner from
the bottom surface..Iaddend.
.Iadd.48. The method of claim 47, further comprising covering the
second conductive film with an insulating material and disposing
the flexible film over the insulating material..Iaddend.
.Iadd.49. A method comprising: providing a plastic substrate
comprising a plurality of recesses, each of the recesses having a
bottom surface and four sidewall surfaces that extend
non-perpendicularly from the bottom surface toward an upper surface
of the substrate; and subsequently performing the steps of:
disposing a plurality of integrated circuits within the plurality
of recesses such that each of the recesses contains no more than a
single respective integrated circuit, each respective integrated
circuit comprising respective RFID circuitry to provide memory and
processing functions, the respective RFID circuitry coupled to
respective first and second antenna ports configured to be coupled
together via a respective antenna; and forming a plurality of
continuous conductive films, each of the continuous conductive
films having a first portion and a second portion, the first
portion being coupled to respective ones of the integrated circuits
disposed within the recesses and the second portion extending above
the upper surface of the substrate..Iaddend.
.Iadd.50. The method of claim 49, wherein the substrate comprises a
plurality of rows of recesses and a plurality of columns of
recesses, and further comprising dividing the substrate into a
plurality of singular substrates after forming the plurality of
conductive films, each of the singular substrates comprising a
single recess..Iaddend.
.Iadd.51. The method of claim 50, wherein each of the continuous
conductive films is disposed above at least one respective sidewall
surface between the first and second portions, and each of the
singular substrates comprises two continuous conductive
films..Iaddend.
.Iadd.52. The method of claim 51, wherein forming the plurality of
continuous conductive films comprises printing a conductive
material..Iaddend.
.Iadd.53. The method or claim 52, wherein the first portion of each
of the continuous conductive films is coupled to respective ones of
the integrated circuits using a conductive adhesive. .Iaddend.
.Iadd.54. A method comprising: providing a substrate comprising a
recess, the recess having a bottom surface and four sidewall
surfaces that extend non-perpendicularly from the bottom surface
toward an upper surface of the substrate, each of the sidewall
surfaces sloping outward from the bottom surface toward the upper
surface; providing an antenna, at least a portion of which is a
first conductive material disposed above the upper surface;
providing an integrated circuit within the recess, the integrated
circuit comprising RFID circuitry to provide memory and processing
functions and coupled to first and second antenna ports of the
integrated circuit; providing a second conductive material,
separated from the first conductive material, having a first region
coupled to the integrated circuit and disposed above the bottom
surface, having a second region coupled to the portion of the
antenna and disposed above the upper surface, and having a third
region between the first and second regions and disposed above one
of the sidewall surfaces; and disposing a flexible film over the
recess, the integrated circuit, the antenna, and the second
conductive material, wherein the first and second antenna ports are
electrically coupled together via the antenna..Iaddend.
.Iadd.55. The method of claim 54, further comprising bonding a
conductive adhesive to the integrated circuit and to the first
region of the second conductive material..Iaddend.
.Iadd.56. The method of claim 55, wherein providing the second
conductive material comprises printing the second conductive
material..Iaddend.
.Iadd.57. The method of claim 56, further comprising the second
conductive material with an insulating material and disposing the
flexible film over the insulating material..Iaddend.
.Iadd.58. The method of claim 57 wherein at least one of the
sidewall surfaces slopes in at least a generally linear manner from
the bottom surface..Iaddend.
Description
.Iadd.More than one reissue application has been filed for the
reissue of U.S. Pat. No. 6,329,213 B1. The reissue applications are
application Ser. Nos. 10/734,072 (the present application),
11/302,543, and 11/496,088, all of which are continuation reissues
of U.S. Pat. No. 6,329,213 B1..Iaddend.
TECHNICAL FIELD
The invention pertains to methods of forming integrated circuits
within substrates, and to embedded circuits. The invention is
thought to have particular application towards methods of forming
integrated circuits within personal cards, such as personal
identification cards and credit cards.
BACKGROUND OF THE INVENTION
Smart cards typically include an integrated circuit providing both
memory and processing functions, have words or pictures printed on
them, and control who uses information stored in the integrated
circuit and how the information is used.
Some smart cards have length and width dimensions corresponding to
those of credit cards. The size of such smart cards is determined
by an international standard (ISO 7816). ISO 7816 also defines the
physical characteristics of the plastic, including temperature
tolerance and flexibility. ISO 7816 also defines the position of
electrical contacts and their functions, and the protocol for
communications between the integrated circuit and readers (vending
machines, pay phones, etc.) The term "smart card", as used herein,
is meant to include cards that include microprocessors. Such cards
might not conform to ISO 7816.
Several types of plastic are used for the casings or housings of
smart cards. PVC and ABS are typical. PVC can be embossed, but is
not recyclable. ABS is not readily embossed, but is recyclable.
Smart cards have many different applications. For example, smart
cards can be pre-paid cards used instead of money for making
purchases from vending machines, gaming machines, gas stations, car
washes, photocopiers, laundry machines, cinemas, fast-food
restaurants, retail outlets, or anywhere where cash is used. For
example, they are commonly used in Europe with public telephones. A
timer is used to detect a balance from the card automatically while
a conversation continues. Smart cards can be used as food stamps,
or for redeeming other government-provided benefits. Because the
transaction is electronic, the telephone, vending machine, etc.
does not need to store cash, so risk of loss due to theft can be
reduced. Change does not need to be stored and disbursed, and
received payment can be directly wired to a bank. Pre-paid cards
can be a form of advertising, because they can have logos or other
information printed on them. The user would typically carry the
card for weeks before using up the value on the card.
To authenticate a conventional credit card, a telephone call must
be made to verify that sufficient funds are available. Smart cards
permit such verification to be performed off-line, thus saving
telecommunication charges. Smart cards thus provide an advantage
over conventional credit cards. Smart cards can also be used as
keys to gain access to restricted areas, such as secure areas of
buildings, or to access parking lots.
Radio frequency identification devices (RFIDs) can also be
considered smart cards if they include an integrated circuit. RFIDs
are described in detail in U.S. patent application Ser. No.
08/705,043, filed Aug. 29, 1996, and incorporated herein by
reference. RFIDs comprising integrated circuits may be referred to
as intelligent RFIDs or as remote intelligent communication (RIC)
devices.
Smart cards will typically contain an integrated circuit, typically
provided as a packaged integrated circuit chip (IC chip). The smart
card may also comprise electrical interconnects for connecting the
IC chip to terminals. In other instances, the electronic
interconnects will comprise an antenna, such as, for example, when
the integrated circuit comprises radio frequency identification
device circuitry. In other instances, an antenna, battery and IC
may be inserted into smart cards. As smart cards are intended to be
conveniently carried by persons, it is desirable to produce smart
cards which are relatively thin, preferably having a size and shape
similar to credit cards. This enables the cards to be carried on a
person, such as, for example, in a persons's wallet.
SUMMARY OF THE INVENTION
The invention encompasses methods for forming integrated circuits
within substrates, and embedded circuits.
In one aspect, the invention encompasses a method of forming an
integrated circuit within a substrate. A recess is formed in the
substrate, and an antenna is printed within the recess. An
integrated circuit chip and a battery are provided in operative
electrical connection with the antenna.
In another aspect, the invention encompasses a method of forming a
plurality of cards. A substrate sheet is provided and a plurality
of recesses are formed within the substrate sheet. The individual
recesses have bottom surfaces and sidewall surfaces joined to the
bottom surfaces. A conductive film is printed within the recesses
to form electrical interconnects within the recesses. The
electrical interconnects extend along the bottom surfaces and the
sidewall surfaces of the recesses, and also on top surfaces of the
substrate sheet. Integrated circuit chips are placed within the
recesses and in electrical connection with the electrical
interconnects. The integrated circuit chips and the conductive film
within the recesses are covered with a protective cover. The
substrate sheet is divided into a plurality of cards.
In another aspect, the invention encompasses an embedded circuit.
The embedded circuit includes a substrate having a recess therein;
a conductive circuit printed within the recess and an integrated
circuit chip bonded to the conductive circuit.
In another aspect, the invention encompasses an embedded circuit.
The embedded circuit includes a substrate having a recess therein;
a conductive circuit provided within the recess; an integrated
circuit chip bonded to the conductive circuit; and a battery in
electrical connection with the integrated circuit chip.
.Iadd.In accordance with another embodiment, a recess is provided
in a plastic substrate containing an integrated circuit comprising
RFID circuitry. A conductive material extends over a sidewall of
the recess and is coupled to the integrated circuit in a first
region and to an antenna in a second region. A flexible film may be
disposed over the recess, the integrated circuit, and the
conductive material..Iaddend.
BRIEF DESCRIPTION OF THE DRAWINGS
Preferred embodiments of the invention are described below with
reference to the following accompanying drawings.
FIG. 1 is a schematic perspective view of a card and a printing pad
at a preliminary step of a first embodiment method of the present
invention.
FIG. 2 is a schematic perspective view of the FIG. 1 card and
printing pad shown at a processing step subsequent to that of FIG.
1.
FIG. 3 is a perspective view of the FIG. 1 card shown at a
processing step subsequent to that of FIG. 2.
FIG. 4 is a perspective view of the FIG. 1 card shown at a
processing step subsequent to that of FIG. 3.
FIG. 5 is a cross-sectional view of the FIG. 4 card taken along
line 5--5 in FIG. 4.
FIG. 6 is a cross-sectional view of the FIG. 1 card taken along
line 5--5 in FIG. 4, and shown at a processing step subsequent to
that of FIG. 5.
FIG. 7 is a cross-sectional view of the FIG. 1 card taken alone
line 5--5 in FIG. 4, and shown at a processing step subsequent to
that of FIG. 5.
FIG. 8 is a perspective view of a card being produced according to
a second embodiment method of the present invention.
FIG. 9 is a cross-sectional view of the FIG. 8 card taken along the
line 9--9 in FIG. 8.
FIG. 10 is a perspective view of a card being produced according to
a third embodiment method of the present invention.
FIG. 11 is a cross-sectional view of the FIG. 10 card taken along
the line 11--11 in FIG. 10.
FIG. 12 is an elevational view of a substrate sheet processed
according to a method of the present invention.
FIG. 13 is an elevational view of the sheet of FIG. 12 at a
processing step shown subsequent to that of FIG. 12.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
This disclosure of the invention is submitted in furtherance of the
constitutional purposes of the U.S. Patent Laws "to promote the
progress of science and useful arts" (Article 1, Section 8).
A first embodiment method of the present invention is described
with reference to FIGS. 1-7. Referring to FIG. 1, a substrate 10 is
shown at a preliminary step of the first embodiment method.
Substrate 10 is preferably a card substrate in the approximate
shape of a credit card. Substrate 10 can comprise any of a number
of materials known to persons of ordinary skill in the art, such as
for example, PVC or ABS plastic. As will become apparent from the
following discussion, substrate 10 might ultimately be used for a
radio frequency card, smart card, or other card built with
multiple, interconnected composites, including an integrated
circuit. Accordingly, substrate 10 preferably comprises a
configuration suitable for one or more of the above-discussed
ultimate uses.
Substrate 10 comprises a substrate body 13, a front surface 12, and
an opposing back surface 11 (shown in FIG. 5). A recess 14 is
provided through front surface 12 and into substrate 10. Recess 14
can be formed by conventional methods. Examples include cutting
with a blade, grinding wheel or laser. Another example method for
forming recess 14 is to form the recess in situ at a time of card
creation by injection molding the card in a shape comprising recess
14. Recess 14 has a bottom surface 16 and sidewall surfaces 18
joined to bottom surface 16. As most clearly shown in FIGS. 5-7,
sidewall surfaces 18 preferably extend non-perpendicularly from
bottom surface 16. Such non-perpendicular orientation of sidewall
surfaces 18 relative to bottom surface 16 can simplify a
below-discussed printing of a circuit 22 (shown in FIG. 3) over
such sidewall surfaces. It is noted, however, that the present
invention also encompasses applications in which sidewall surfaces
18 extend perpendicularly from bottom surface 16.
Still referring to FIG. 1, a printing pad 20 is elevated above
substrate 10. Printing pad 20 preferably comprises a deformable
material, such as for example, foam, sponge, or silicone rubber. A
circuit pattern 21 is formed on printing pad 20, and comprises, for
example, a conductive film. Circuit pattern 21 can be formed by,
for example, pressing pad 20 onto a plate having a shape
corresponding to circuit pattern 21 etched within it.
Referring to FIG. 2, printing pad 20 is pressed against substrate
10 to transfer circuit pattern 21 to substrate 10 and thereby print
a circuit 22 (shown in FIG. 3) upon substrate 10 and within recess
14. In the shown embodiment, printing pad 20 is configured to print
the circuit pattern on bottom surface 16, on two of sidewall
surfaces 18, and on upper surf ace 12. In alternate embodiments
which are not shown, printing pad 20 can be configured to print on
less than all of surfaces 16, 18 and 20. For instance, in such
alternate embodiments, printing pad 20 may be configured to print
only on bottom surface 16, or only on bottom surface 16 and one of
the sidewall surfaces 18. Suitable materials which may be pad
printed to form circuit 22 are conductive films, such as, for
example, printed thick film (PTFs) comprising silver-filled organic
material. It is noted that, although pad printing is shown, the
printing can comprise other printing methods known to persons of
ordinary skill in the art, including, for example, stencil
printing, screen printing spray printing, needle dispense printing
etc. After conductive circuit 22 is printed, the circuit can be
cured by conventional methods.
After curing, circuit 22 will have a thickness and associated
degree of conductivity. If the conductive is lower than desired as
may occur if, for example, conductive material of circuit 22 is too
thin, or not adequately a low resistance material, the conductivity
can be enhanced by providing an electroless plated metal, such as
copper or nickel, against substrate 10 and circuit 22. The
electroless plated metal selectively plates conductive circuit 22,
while not plating non-conductive surfaces of substrate 10. The
electroless plating of metal can be accomplished by conventional
methods.
Referring to FIG. 3, circuit 22 preferably comprises conductive
interconnects 23 and 24, and an antenna 26. Interconnect 23
comprises nodes 25 and 27, interconnect 24 comprises nodes 28 and
30, and antenna 26 comprises nodes 32 and 33. Nodes 25, 27, 28, 30,
32 and 33 are illustrated as being wider than the rest of
interconnects 23 and 24, and antenna 26. However, as will be
appreciated by persons of ordinary skill in the art, nodes 25, 27,
28, 30, 32 and 33 could also be a same size as the rest of
interconnects 23, 24 and antenna 26; or narrower than the rest of
interconnects 23, 24 and antenna 26. Note 27 preferably comprises
the shown arcuate shape complementary to an outer surface of a
battery 36 (shown in FIG. 4), which is to be joined to node 27. In
the shown preferred embodiment, antenna 26 is a loop antenna
comprising a predominant portion outside of recess 14 and on
substrate surface 12. In other embodiments (not shown), antenna 26
could be entirely within recess 14, or comprise a predominate
portion within recess 14.
In the preferred embodiment, antenna 26 constitutes a part of, and
is formed at the same time as, the other integrated circuitry. It
is noted that antenna 26 could be formed in two steps, with a
portion of antenna 26 being formed before or after pad printing of
circuit 22. For instance, the portion of antenna 26 extending along
upper surface 12 could be formed prior to printing circuit 22.
Then, a portion of antenna 26 could be printed as part of circuit
22 to create nodes 32 and 33, and to connect the previously formed
portion of antenna 26 with nodes 32 and 33. In such circumstances,
the portion of antenna 26 which is not formed as part of circuit 22
could be formed by methods other than those utilized to form
circuit 22. For instance, if circuit 22 is pad printed, the portion
of antenna 26 not formed as part of circuit 22 could be formed by a
method other than pad printing. Such other methods will be
recognized by persons of ordinary skill in the art.
Referring to FIG. 4, electrical components 36 and 38 are bonded to
one or more of nodes 25, 27, 28, 30, 32 and 33 (shown in FIG. 3).
By way of example only, electrical component 36 comprises a battery
and component 38 comprises a monolithic integrated circuit formed
on a chip. Components 36 and 38 may be bonded to nodes 25, 27, 28,
30, 32 and 33 (shown in FIG. 3), utilizing a conductive adhesive 35
which is cured after provision of components 36 and 38. An example
conductive adhesive 35 is a conductive epoxy. Battery 36 could
alternatively be provided directly bonded to integrated circuit
chip 38. In such circumstances, the bonding of battery 36 to
integrated circuit 38 can occur either before or after placing
integrated circuit 38 and battery 36 within recess 14. Also, as
will be recognized by persons of ordinary skill in the art, at
least one of the electrical components 36 or 38 could be provided
externally of recess 14.
In the illustrated embodiment, interconnects 23 and 24 connect
battery 36 to integrated circuit 38, and antenna 26 connects with
integrated circuit 38. Battery 36, interconnects 23 and 24,
integrated circuit 38 and antenna 26 together form a radio
frequency identification device (RFID).
After provision of circuit 22 and one or both of components 36 and
38 within recess 14, a protective cover is ideally formed over
circuit 22 and recess 14. FIGS. 6 and 7 illustrate two methods of
protectively covering circuit 22 and the components within recess
14. Referring first to FIG. 6, a cap 40 can be adhered over
substrate 10 and over recess 14. Cap 40 may be adhered, for
example, by adhesive, such as glue, or by mechanical fasteners,
such as staples or screws. Example materials for cap 40 include
plastic metal, and flexible or rigid adhesive tape. In the shown
embodiment, portions of loop antenna 26 are between cap 40 and
substrate body 13. Such portions of loop antenna 26 are generally
thin enough that they do not interfere with bonding of cap 40 to
substrate body 13. To further minimize interference of such
portions of loops antenna 26 with bonding of cap 40 to substrate
body 13, cap 40 can be formed of a material which conforms over and
around loop antenna 26, such as, for example, a deformable
material. Also, in embodiments which are not shown, antenna 26 can
be formed entirely within recess 14 to minimize interference of
antenna 26 with bonding of cap 40 to substrate body 13.
Referring to FIG. 7, circuitry 22 and components 36 and 38 can be
covered with an encapsulant 42. Such encapsulant may comprise, for
example, a low temperature curing insulating material, such as, for
example, a two-part epoxy or urethane. Encapsulant 42 will
preferably be provided initially as a liquid material and to
overfill recess 14 and overlay antenna 26. Encapsulant 42 can then
be cured into a solid mass, and either milled or sanded to form the
shown preferred substantially planar upper surface 44.
It is noted that the methods of FIGS. 6 and 7 are merely example
methods for covering circuitry proximate and within recess 14. The
invention encompasses other methods for covering such circuitry
which will be recognized by persons of ordinary skill in the art.
The methods of FIGS. 6 and 7 could also be combined. For instance,
a recess could be partially filled with an encapsulant and then
covered. Such combined methods may have particular application
toward sealing cards containing multiple recesses which are
discussed below. In such cases, an integrated circuit could be
within one recess and a battery within another. The integrated
circuit could be covered with encapsulant and/or a cap, and the
battery covered only with a removable cap. In such applications the
integrated circuit would be well-protected and the battery could be
easily replaceable.
After provision of a protective cover over recess 14, the
construction of a card is substantially finished. The card may then
be covered with a laminating film for cosmetic, printability, or
logo reasons. An example laminating film would be a thin (less than
about one mil) PVC sheet bonded to substrate 10 with an
adhesive.
A second embodiment method of the present invention is described
with reference to FIGS. 8 and 9. In describing FIGS. 8 and 9,
numbering similar to that utilized above in describing FIGS. 1-7
will be used, with differences indicated by the suffix "a" or by
different numerals.
Referring to FIGS. 8 and 9, a substrate 10a is illustrated.
Substrate 10a comprises a first recess 52 and a second recess 54.
In the illustrated and preferred embodiments, first recess 52 is
formed in the substrate and second recess 54 is formed within first
recess 52 and essentially constitutes a part thereof. A conductive
circuit 22a is formed within recesses 52 and 54 and comprises
interconnects 23a and 24, and antenna 26a. Antenna 26a is a loop
antenna which extends beyond recesses 52 and 54. Interconnects 23a
and 24a connect electrical components 36a and 38a. Interconnects
23a and 24a, and antenna 26a, are preferably formed by printing a
conductive film within first and second recesses 52 and 54,
utilizing procedures analogous to those discussed above with
reference to FIGS. 1-3.
In the illustrated embodiment, components 36a and 38a are each
within a recess, with component 36a being within first recess 52
and component 38a being within second recess 54. First recess 52
comprises a bottom surface 56 and sidewall surfaces 58. Second
recess 54 comprises a bottom surface 60 and sidewall surfaces 62.
Sidewall surfaces 58 and 62 can extend non-perpendicularly form
bottom surfaces 56 and 60, respectively, to simply printing of
circuit 22a over such sidewall surfaces. First recess 52 is
separated from second recess 54 by one of the sidewall surfaces 62.
The separating sidewall 62 extends non-perpendicularly from both of
bottom surface 56 and bottom surface 60. Interconnects 23a and 24a
extend over the separating sidewall surface 62 and along bottom
surfaces 60 and 56. Interconnects 23a and 24a thus extend
continuously from electrical component 36a to electrical component
38a.
Substrate 10a comprises a front surface 12a and an opposing back
surface 11a. Preferably, first recess 52 and second recess 54 both
extend through the same of either front surface 12a or back surface
11a. In FIGS. 8 and 9, recesses 52 and 54 are illustrated as both
extending through front surface 12a.
Subsequent processing of substrate 10a can be performed in
accordance with the processing of either FIG. 6 or FIG. 7 to cover
first and second electrical components 36a and 38a, and electrical
circuit 22a, with at least one protective cover.
A third embodiment method of the present invention is described
with reference to FIGS. 10 and 11. In describing FIGS. 10 and 11,
numbering similar to that utilized above in describing FIGS. 1-7
will be used, with differences indicated by the suffix "b" or by
different numerals.
A substrate 10b comprises a substrate body 13b, a front surface
12b, and an opposing back surface 11b. A recess 14b is provided
through front surface 12b and into substrate 10b. Electrical
components 36b and 38b are within recess 14b and connected by
interconnects 23b and 24b. A loop antenna 26b is electrically
connected with component 38b. Loop antenna 26b extends from
component 38b, out of recess 14b, and along surface 12b of
substrate 10b. Antenna 26b crosses over itself at a bypass 70.
Antenna 26b comprises a first portion 66 and a second portion 68 at
bypass 70, with second portion 68 crossing over first portion 66.
Bypass 70 comprises an insulative material 72 separating first
portion 66 from second portion 68. Insulative material 72 can
comprise, for example, silicon dioxide.
Methods for forming antenna 26b will be recognized by persons of
ordinary skill in the art. Such methods could include, for example,
printing methods similar to those discussed above in discussing
FIGS. 1-3, with the exception that two printing steps would be
utilized in forming antenna 26b. More particularly, a first
printing step would be utilized to form the portion of antenna 26b
underlying insulative material 72, and a second printing step would
be utilized to form the portion of antenna 26b overlying material
72. Insulative material 72 would be formed between the two printing
steps. Insulative material 72 can be formed by conventional
methods.
Although the embodiment of FIGS. 10 and 11 is illustrated with only
two loops and only one bypass 70, persons of ordinary skill in the
art will recognize that alternate embodiments could be formed
comprising more than two loops and a plurality of bypasses 70. The
utilization of one or more bypasses 70 can advantageously permit
relatively long loop antennas to be formed on a card substrate.
It is noted that although antenna second portion 68 is illustrated
as being substantially perpendicular to antenna first portion 66 at
bypass 70, the invention encompasses other embodiments (not shown)
in which an antenna second portion is non-perpendicular to an
antenna first portion at a bypass of the antenna portions.
The processing described above with reference to FIGS. 1-11 forms
embedded circuits within substrates. Such embedded circuits can
comprise, for example, circuitry 22, 22a or 22b, and one or more of
components 36,36a,36b,38, 38a and 38b.
Although FIGS. 1-11 illustrate formation of a single card, the
invention encompasses methods in which a plurality of cards are
formed. Such plurality of cards may be formed by forming a number
of recesses within a single sheet, and then dividing the sheet into
singulated cards. The division into singulated cards may occur
before or after any of the steps illustrated in FIGS. 1-11. For
example, the division into singulated cards may occur after
printing of conductive circuitry (shown in FIG. 2), and prior to
provision of components 36 and 38 within a recess. The division of
a large sheet into singulated sheets can be performed by a number
of methods known to persons of ordinary skill in the art,
including, for example, sawing or cutting mechanically or by a
laser.
The formation of a number of individual cards from a single sheet
substrate is illustrated in FIGS. 12 and 13. In referring to FIGS.
12 and 13, similar numbering to that utilized above in describing
FIGS. 1-7 is utilized, with differences being indicated by the
suffix "c" or with different numerals. Referring to FIG. 12, a
sheet substrate 50 comprises a plurality of recesses 14c. Referring
to FIG. 13, the sheet substrate 50 (shown in FIG. 12) is divided
into a number of singular card substrates 10c. The individual card
substrates 10c comprise at least one recess 14c. It is noted that
the invention encompasses methods in which not all of the
individual substrates 10c comprise equal numbers of recesses 14c,
and encompasses embodiments in which some of the individual
substrates comprise no recess 14c. However, generally at least two
of the formed substrates 10c will comprise at least one recess
14c.
In compliance with the statue, the invention has been described in
language more or less specific as to structural and methodical
features. It is to be understood, however, that the invention is
not limited to the specific features shown and described, since the
means herein disclosed comprise preferred forms of putting the
invention into effect. The invention is, therefore, claimed in any
of its forms or modifications within the proper scope of the
appended claims appropriately interpreted in accordance with the
doctrine of equivalents.
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