U.S. patent application number 10/592371 was filed with the patent office on 2007-11-29 for thin semiconductor device and operation method of thin semiconductor device.
This patent application is currently assigned to Semiconductor Energy Laboratory Co., Ltd.. Invention is credited to Yasuyuki Arai, Takeshi Osada, Yuko Tachimura, Shunpei Yamazaki.
Application Number | 20070273476 10/592371 |
Document ID | / |
Family ID | 35056394 |
Filed Date | 2007-11-29 |
United States Patent
Application |
20070273476 |
Kind Code |
A1 |
Yamazaki; Shunpei ; et
al. |
November 29, 2007 |
Thin Semiconductor Device And Operation Method Of Thin
Semiconductor Device
Abstract
The present invention provides a thin semiconductor device in
which its security such as prevention of counterfeit or information
leakage is to be enhanced. One feature of the present invention is
a thin semiconductor device in which a plurality of thin film
integrated circuits are mounted and in which at least one
integrated circuit is different from the other integrated circuits
in any one of a specification, layout, frequency for transmission
or reception, a memory, a communication means, a communication rule
and the like. According to the present invention, a thin
semiconductor device tag having the plurality of thin film
integrated circuits communicates with a reader/writer and at least
one of the thin film integrated circuits receives a signal to write
information in a memory, and the information written in the memory
determines which of the thin film integrated circuits
communicates.
Inventors: |
Yamazaki; Shunpei; (Tokyo,
JP) ; Osada; Takeshi; (Kanagawa, JP) ; Arai;
Yasuyuki; (Kanagawa, JP) ; Tachimura; Yuko;
(Kanagawa, JP) |
Correspondence
Address: |
ERIC ROBINSON
PMB 955
21010 SOUTHBANK ST.
POTOMAC FALLS
VA
20165
US
|
Assignee: |
Semiconductor Energy Laboratory
Co., Ltd.
398 Hase
Atsugi-shi
JP
243-0036
|
Family ID: |
35056394 |
Appl. No.: |
10/592371 |
Filed: |
March 24, 2005 |
PCT Filed: |
March 24, 2005 |
PCT NO: |
PCT/JP05/06214 |
371 Date: |
September 11, 2006 |
Current U.S.
Class: |
340/5.61 ;
257/390; 340/5.6 |
Current CPC
Class: |
G06K 19/07718 20130101;
G06K 19/07749 20130101; G06K 7/0008 20130101; G06K 19/0723
20130101; G06K 19/072 20130101 |
Class at
Publication: |
340/005.61 ;
257/390; 340/005.6 |
International
Class: |
G06K 19/077 20060101
G06K019/077; H01L 29/94 20060101 H01L029/94 |
Foreign Application Data
Date |
Code |
Application Number |
Mar 26, 2004 |
JP |
2004-092972 |
Claims
1. A thin semiconductor device comprising: a plurality of thin film
integrated circuits provided with a semiconductor film of 40 nm to
170 nm thick, wherein at least one integrated circuit is different
from the other integrated circuits in any of a shape and a layout
of an antenna, frequency, a communication means, and a
communication rule.
2. A thin semiconductor device comprising: a plurality of thin film
integrated circuits provided with an antenna and a semiconductor
film of 40 nm to 170 nm thick, wherein at least one integrated
circuit is different from the other integrated circuits in any of a
shape and a layout of an antenna, frequency, a communication means,
and a communication rule.
3. A thin semiconductor device comprising: a plurality of thin film
integrated circuits provided with an antenna, a memory and a
semiconductor film of 40 nm to 170 nm thick, wherein at least one
integrated circuit is different from the other integrated circuits
in any of a shape and a layout of an antenna, frequency, a
communication means, and a communication rule.
4. The thin semiconductor device according to claim 3, wherein the
plurality of thin film integrated circuits shares the memory.
5. The thin semiconductor device according to claim 3, wherein the
memory is any one of a nonvolatile memory, a ROM, a mask ROM, a
flash memory, an FRAM, an EPROM, an EEPROM, a DRAM and an SRAM.
6. The thin semiconductor device according to claim 2, wherein the
antennas of the plurality of thin film integrated circuits are
different in length from one another.
7. The thin semiconductor device according to claim 3, wherein the
antennas of the plurality of thin film integrated circuits are
different in length from one another.
8. The thin semiconductor device according to claim 2, wherein the
antenna is integrated over the semiconductor film.
9. The thin semiconductor device according to claim 3, wherein the
antenna is integrated over the semiconductor film.
10. The thin semiconductor device according to claim 1, wherein the
mode of the thin film integrated circuit includes a central
processing unit, a memory and a layout of an antenna of the thin
film integrated circuit.
11. The thin semiconductor device according to claim 2, wherein the
mode of the thin film integrated circuit includes a central
processing unit, a memory and a layout of an antenna of the thin
film integrated circuit.
12. The thin semiconductor device according to claim 3, wherein the
mode of the thin film integrated circuit includes a central
processing unit, a memory and a layout of an antenna of the thin
film integrated circuit.
13. The thin semiconductor device according to claim 1, wherein the
frequency is any of a sub millimeter wave 300 GHz to 3 THz, an
extremely-high-frequency wave 30 GHz to 300 GHz, a
super-high-frequency wave 3 GHz to 30 GHz, an ultra-high-frequency
wave 300 MHz to 3 GHz, a very-high-frequency 30 MHz to 300 MHz, a
high-frequency wave 3 MHz to 30 MHz, a medium-frequency wave 300
KHz to 3 MHz, a long-frequency wave 30 KHz to 300 KHz and a
very-long frequency wave 3 KHz to 30 KHz.
14. The thin semiconductor device according to claim 2, wherein the
frequency is any of a sub millimeter wave 300 GHz to 3 THz, an
extremely-high-frequency wave 30 GHz to 300 GHz, a
super-high-frequency wave 3 GHz to 30 GHz, an ultra-high-frequency
wave 300 MHz to 3 GHz, a very-high-frequency 30 MHz to 300 MHz, a
high-frequency wave 3 MHz to 30 MHz, a medium-frequency wave 300
KHz to 3 MHz, a long-frequency wave 30 KHz to 300 KHz and a
very-long frequency wave 3 KHz to 30 KHz.
15. The thin semiconductor device according to claim 3, wherein the
frequency is any of a sub millimeter wave 300 GHz to 3 THz, an
extremely-high-frequency wave 30 GHz to 300 GHz, a
super-high-frequency wave 3 GHz to 30 GHz, an ultra-high-frequency
wave 300 MHz to 3 GHz, a very-high-frequency 30 MHz to 300 MHz, a
high-frequency wave 3 MHz to 30 MHz, a medium-frequency wave 300
KHz to 3 MHz, a long-frequency wave 30 KHz to 300 KHz and a
very-long frequency wave 3 KHz to 30 KHz.
16. The thin semiconductor device according to claim 1, wherein the
communication means is a digital modulation system and is any one
of amplitude shift keying, frequency shift keying and phase shift
keying.
17. The thin semiconductor device according to claim 2, wherein the
communication means is a digital modulation system and is any one
of amplitude shift keying, frequency shift keying and phase shift
keying.
18. The thin semiconductor device according to claim 3, wherein the
communication means is a digital modulation system and is any one
of amplitude shift keying, frequency shift keying and phase shift
keying.
19. The thin semiconductor device according to claim 1, wherein the
communication means is an analog modulation system and is any of
amplitude modulation, frequency modulation and phase
modulating.
20. The thin semiconductor device according to claim 2, wherein the
communication means is an analog modulation system and is any of
amplitude modulation, frequency modulation and phase
modulating.
21. The thin semiconductor device according to claim 3, wherein the
communication means is an analog modulation system and is any of
amplitude modulation, frequency modulation and phase
modulating.
22. The thin semiconductor device according to claim 1, wherein the
communication means is either of one-way communication and two-way
communication, and is any of a space division multiplex access
method, a polarization division multiplex access method, a
frequency-division multiplex access method, a time-division
multiplex access method, a code division multiplex access method
and an orthogonal frequency division multiplexing method.
23. The thin semiconductor device according to claim 2, wherein the
communication means is either of one-way communication and two-way
communication, and is any of a space division multiplex access
method, a polarization division multiplex access method, a
frequency-division multiplex access method, a time-division
multiplex access method, a code division multiplex access method
and an orthogonal frequency division multiplexing method.
24. The thin semiconductor device according to claim 3, wherein the
communication means is either of one-way communication and two-way
communication, and is any of a space division multiplex access
method, a polarization division multiplex access method, a
frequency-division multiplex access method, a time-division
multiplex access method, a code division multiplex access method
and an orthogonal frequency division multiplexing method.
25. The thin semiconductor device according to claim 1 is a
card.
26. The thin semiconductor device according to claim 2 is a
card.
27. The thin semiconductor device according to claim 3 is a
card.
28. A thin semiconductor device having a plurality of thin film
integrated circuits provided with a semiconductor film of 40 nm to
170 nm thick, the thin semiconductor device comprising: an antenna
by which at least one thin film integrated circuit of the plurality
of thin film integrated circuits receives a signal transmitted from
a reader/writer; a memory into which information is written by the
received signal; and an electronic key in which information about
which of the plurality of thin film integrated circuits
communicates, is input.
29. A thin semiconductor device having a plurality of thin film
integrated circuits provided with a semiconductor film of 40 nm to
170 nm thick, the thin semiconductor device comprising: an antenna
by which at least one thin film integrated circuit of the plurality
of thin film integrated circuits receives a signal transmitted from
a reader/writer; a memory into which information is written by the
received signal; an electronic key in which information about which
of the plurality of thin film integrated circuits communicates, is
input; and a control circuit for controlling which of the plurality
of thin film integrated circuits communicates.
30. The thin semiconductor device according to claim 29, wherein
the control circuit controls writing in and readout from the memory
depending on the electronic key.
31. The thin semiconductor device according to claim 28, wherein
the electronic key is updated by the signal which has been received
by the thin film integrated circuit.
32. The thin semiconductor device according to claim 29, wherein
the electronic key is updated by the signal which has been received
by the thin film integrated circuit.
33. The thin semiconductor device according to claim 28, wherein at
least one thin film integrated circuit of the plurality of thin
film integrated circuits receives a signal depending on a frequency
transmitted from the reader/writer.
34. The thin semiconductor device according to claim 29, wherein at
least one thin film integrated circuit of the plurality of thin
film integrated circuits receives a signal depending on a frequency
transmitted from the reader/writer.
35. The thin semiconductor device according to claim 33, wherein
the frequency is any of a sub millimeter wave 300 GHz to 3 THz, an
extremely-high-frequency wave 30 GHz to 300 GHz, a
super-high-frequency wave 3 GHz to 30 GHz, an ultra-high-frequency
wave 300 MHz to 3 GHz, a very-high-frequency 30 MHz to 300 MHz, a
high-frequency wave 3 MHz to 30 MHz, a medium-frequency wave 300
KHz to 3 MHz, a long-frequency wave 30 KHz to 300 KHz and a
very-long frequency wave 3 KHz to 30 KHz.
36. The thin semiconductor device according to claim 34, wherein
the frequency is any of a sub millimeter wave 300 GHz to 3 THz, an
extremely-high-frequency wave 30 GHz to 300 GHz, a
super-high-frequency wave 3 GHz to 30 GHz, an ultra-high-frequency
wave 300 MHz to 3 GHz, a very-high-frequency 30 MHz to 300 MHz, a
high-frequency wave 3 MHz to 30 MHz, a medium-frequency wave 300
KHz to 3 MHz, a long-frequency wave 30 KHz to 300 KHz and a
very-long frequency wave 3 KHz to 30 KHz.
37. The thin semiconductor device according to claim 28, wherein at
least one thin film integrated circuit of the plurality of thin
film integrated circuits receives a signal depending on a
communication means transmitted from the reader/writer.
38. The thin semiconductor device according to claim 29, wherein at
least one thin film integrated circuit of the plurality of thin
film integrated circuits receives a signal depending on a
communication means transmitted from the reader/writer.
39. The thin semiconductor device according to claim 37, wherein
the communication means is a digital modulation system and is any
one of amplitude shift keying, frequency shift keying and phase
shift keying.
40. The thin semiconductor device according to claim 38, wherein
the communication means is a digital modulation system and is any
one of amplitude shift keying, frequency shift keying and phase
shift keying.
41. The thin semiconductor device according to claim 37, wherein
the communication means is an analog modulation system and is any
of amplitude modulation, frequency modulation and phase
modulating.
42. The thin semiconductor device according to claim 38, wherein
the communication means is an analog modulation system and is any
of amplitude modulation, frequency modulation and phase
modulating.
43. The thin semiconductor device according to claim 37, wherein
the communication means is either of one-way communication and
two-way communication, and is any of a space division multiplex
access method, a polarization division multiplex access method, a
frequency-division multiplex access method, a time-division
multiplex access method, a code division multiplex access method
and an orthogonal frequency division multiplexing method.
44. The thin semiconductor device according to claim 38, wherein
the communication means is either of one-way communication and
two-way communication, and is any of a space division multiplex
access method, a polarization division multiplex access method, a
frequency-division multiplex access method, a time-division
multiplex access method, a code division multiplex access method
and an orthogonal frequency division multiplexing method.
45. An operation method of a thin semiconductor device having a
plurality of thin film integrated circuits provided with a
semiconductor film of 40 nm to 170 nm thick, comprising the steps
of: communicating with a reader/writer; writing information in a
memory by a signal received by at least one thin film integrated
circuit of the plurality of thin film integrated circuits; and
communicating with any of the plurality of thin film integrated
circuits depending on information written in the memory.
46. An operation method of a thin semiconductor device having a
plurality of thin film integrated circuits provided with an antenna
and a semiconductor film of 40 nm to 170 nm thick, comprising the
steps of: communicating with a reader/writer; writing information
in a memory by a signal received by at least one thin film
integrated circuit of the plurality of thin film integrated
circuits; and communicating with any of the plurality of thin film
integrated circuits depending on information written in the
memory.
47. An operation method of a thin semiconductor device having a
plurality of thin film integrated circuits provided with an
antenna, a memory and a semiconductor film of 40 nm to 170 nm
thick, comprising the steps of: communicating with a reader/writer;
writing information in the memory by a signal received by at least
one thin film integrated circuit of the plurality of thin film
integrated circuits; and communicating with any of the plurality of
thin film integrated circuits depending on information written in
the memory.
48. The operation method of a thin semiconductor device according
to claim 45, wherein at least one thin film integrated circuit of
the plurality of thin film integrated circuits receives a signal
depending on a frequency transmitted from the reader/writer.
49. The operation method of a thin semiconductor device according
to claim 46, wherein at least one thin film integrated circuit of
the plurality of thin film integrated circuits receives a signal
depending on a frequency transmitted from the reader/writer.
50. The operation method of a thin semiconductor device according
to claim 47, wherein at least one thin film integrated circuit of
the plurality of thin film integrated circuits receives a signal
depending on a frequency transmitted from the reader/writer.
51. The operation method of a thin semiconductor device according
to claim 48, wherein the frequency is any of a sub millimeter wave
300 GHz to 3 THz, an extremely-high-frequency wave 30 GHz to 300
GHz, a super-high-frequency wave 3 GHz to 30 GHz, an
ultra-high-frequency wave 300 MHz to 3 GHz, a very-high-frequency
30 MHz to 300 MHz, a high-frequency wave 3 MHz to 30 MHz, a
medium-frequency wave 300 KHz to 3 MHz, a long-frequency wave 30
KHz to 300 KHz and a very-long frequency wave 3 KHz to 30 KHz.
52. The operation method of a thin semiconductor device according
to claim 49, wherein the frequency is any of a sub millimeter wave
300 GHz to 3 THz, an extremely-high-frequency wave 30 GHz to 300
GHz, a super-high-frequency wave 3 GHz to 30 GHz, an
ultra-high-frequency wave 300 MHz to 3 GHz, a very-high-frequency
30 MHz to 300 MHz, a high-frequency wave 3 MHz to 30 MHz, a
medium-frequency wave 300 KHz to 3 MHz, a long-frequency wave 30
KHz to 300 KHz and a very-long frequency wave 3 KHz to 30 KHz.
53. The operation method of a thin semiconductor device according
to claim 50, wherein the frequency is any of a sub millimeter wave
300 GHz to 3 THz, an extremely-high-frequency wave 30 GHz to 300
GHz, a super-high-frequency wave 3 GHz to 30 GHz, an
ultra-high-frequency wave 300 MHz to 3 GHz, a very-high-frequency
30 MHz to 300 MHz, a high-frequency wave 3 MHz to 30 MHz, a
medium-frequency wave 300 KHz to 3 MHz, a long-frequency wave 30
KHz to 300 KHz and a very-long frequency wave 3 KHz to 30 KHz.
54. The operation method of a thin semiconductor device, according
to claim 45, control is done by a communication means so that a
signal is received by at least one of the plurality of thin film
integrated circuits.
55. The operation method of a thin semiconductor device, according
to claim 46, control is done by a communication means so that a
signal is received by at least one of the plurality of thin film
integrated circuits.
56. The operation method of a thin semiconductor device, according
to claim 47, control is done by a communication means so that a
signal is received by at least one of the plurality of thin film
integrated circuits.
57. The operation method of a thin semiconductor device according
to claim 54, wherein the communication means is a digital
modulation system and is any one of amplitude shift keying,
frequency shift keying and phase shift keying.
58. The operation method of a thin semiconductor device according
to claim 55, wherein the communication means is a digital
modulation system and is any one of amplitude shift keying,
frequency shift keying and phase shift keying.
59. The operation method of a thin semiconductor device according
to claim 56, wherein the communication means is a digital
modulation system and is any one of amplitude shift keying,
frequency shift keying and phase shift keying.
60. The operation method of a thin semiconductor device according
to claim 54, wherein the communication means is an analog
modulation system and is any of amplitude modulation, frequency
modulation and phase modulating.
61. The operation method of a thin semiconductor device according
to claim 55, wherein the communication means is an analog
modulation system and is any of amplitude modulation, frequency
modulation and phase modulating.
62. The operation method of a thin semiconductor device according
to claim 56, wherein the communication means is an analog
modulation system and is any of amplitude modulation, frequency
modulation and phase modulating.
63. The operation method of a thin semiconductor device according
to claim 54, wherein the communication means is either of one-way
communication and two-way communication, and is any of a space
division multiplex access method (SDMA), a polarization division
multiplex access method, a frequency-division multiplex access
method, a time-division multiplex access method, a code division
multiplex access method and an orthogonal frequency division
multiplexing method, and wherein a signal is transmitted to at
least of the plurality of thin film integrated circuits by
conducting any one of the communication means.
64. The operation method of a thin semiconductor device according
to claim 55, wherein the communication means is either of one-way
communication and two-way communication, and is any of a space
division multiplex access method (SDMA), a polarization division
multiplex access method, a frequency-division multiplex access
method, a time-division multiplex access method, a code division
multiplex access method and an orthogonal frequency division
multiplexing method, and wherein a signal is transmitted to at
least of the plurality of thin film integrated circuits by
conducting any one of the communication means.
65. The operation method of a thin semiconductor device according
to claim 56, wherein the communication means is either of one-way
communication and two-way communication, and is any of a space
division multiplex access method (SDMA), a polarization division
multiplex access method, a frequency-division multiplex access
method, a time-division multiplex access method, a code division
multiplex access method and an orthogonal frequency division
multiplexing method, and wherein a signal is transmitted to at
least of the plurality of thin film integrated circuits by
conducting any one of the communication means.
Description
TECHNICAL FIELD
[0001] The present invention relates to a thin semiconductor device
in which a thin film integrated circuit is mounted and an operation
method of the thin semiconductor device.
BACKGROUND ART
[0002] As for a conventional non-contact IC card, there is proposed
a structure in which capacity adjustment of a capacitor for setting
the resonance frequency of a resonant circuit in an antenna
mechanism is not required, mechanical damages to elements
constituting a card are minimalized, and mass-productivity is
increased. The structure has a plane coil which is connected to a
non-contact IC chip and plural other plane coils which are arranged
in the periphery thereof (References 1: Japanese Patent Laid-Open
No. 2001-109861 and Reference 2: Japanese Patent Laid-Open No.
2001-109862). According to References 1 and 2, each of resonance
frequencies is a frequency of high frequency electromagnetic field
from a reader/writer device, a frequency shifted up/down to some
extent, or the like, and several of the frequencies can be combined
so as not to be interfered with one another, thereby obtaining
broadband resonance properties.
[0003] There is an IC card in which a plurality of IC chips each
using the same frequency and a booster coil are mounted on a base
material of a card so as to expand a function of an IC card
(Reference 3: Japanese Patent Laid Open No. 2003-331238). According
to Reference 3, the IC chips use the booster coil as a common
external antenna and thus, can individually conduct data
communication with an external reader/writer.
DISCLOSURE OF INVENTION
[0004] As for such conventional IC cards according to References 1
to 3, preventing counterfeit of such cards has been not considered.
No measures for preventing information leakage have been made.
[0005] It is an object of the present invention to provide a thin
semiconductor device whose security for prevention of counterfeit
or information leakage is to be enhanced.
[0006] The present invention has been made in view of the above
described problems. One feature of the present invention is a thin
semiconductor device in which a plurality of thin film integrated
circuits are mounted and in which at least one integrated circuit
is different from the other integrated circuits in any one of
specification, layout, frequency for transmission or reception
(referred to as transmission/reception collectively) (simply
referred to as frequency), memory, communication means,
communication rule and the like.
[0007] The layout of the thin film integrated circuit includes
layouts of a central processing unit (CPU), a memory, an antenna
and the like. Differences in the layouts of antennas means
difference in shapes or lengths of antennas. Difference in the
shapes or lengths of antennas causes difference in frequencies.
This frequency can adopt any of a sub millimeter wave (300 GHz to 3
THz), an extremely-high-frequency wave (EHF) (30 GHz to 300 GHz), a
super-high-frequency wave (SHF) (3 GHz to 30 GHz), an
ultra-high-frequency wave (UHF) (300 MHz to 3 GHz), a
very-high-frequency (VHF) (30 MHz to 300 MHz), a high-frequency
wave (HF) (3 MHz to 30 MHz), a medium-frequency wave (MF) (300 KHz
to 3 MHz), a long-frequency wave (LF) (30 KHz to 300 KHz) and a
very-long frequency wave (VLF) (3 KHz to 30 KHz). The specific
frequency can adopt any of 135 KHz, 6.78 MHz, 13.56 MHz, 27.125
MHz, 40.68 MHz, 433.92 MHz, 869.0 MHz, 915.0 MHz, 2.45 GHz, 5.8 GHz
and 24.125 GHz. If the frequencies are, for example, 2.45 GHz and
900 MHz, the shapes of antennas are different. In other words, the
antenna may be a dipole type one or a loop type one.
[0008] The memory may adopt either a memory that can store
information even when the power is off, or a memory that cannot
store information when the power is off. The memories that can
store information even when the power is off include a nonvolatile
memory, a ROM (such as mask ROM), a flash memory, an FRAM, an
EPROM, and an EEPROM. The memories that cannot store information
when the power is off include a DRAM and an SRAM. In such memories,
information can be written in or reading when a signal is input.
The signal includes a signal for selecting a memory to be reading,
i.e., a selection signal, in addition to the signal for writing to
information. According to the present invention, when these
memories are different, information memorized in the memories are
different in some cases. Differences in information means that
memorizing modes of a memory such as rewritable, erasable and
overwritable of information are different.
[0009] Differences in communication means of thin film integrated
circuits means to adopt either a digital modulation system or an
analog modulation system. The digital modulation system is any of
amplitude shift keying (ASK), frequency shift keying (FSK) and
phase shift keying (PSK). The analog modulation system is any of
amplitude modulation (AM), frequency modulation (FM) and phase
modulation (PM).
[0010] The communication means can adopt either one-way
communication or two-way communication. Further, it can adopt any
of a space division multiplex access method (SDMA), a polarization
division multiplex access method (PDMA), a frequency-division
multiplex access method (FDMA), a time-division multiplex access
method (TDMA), a code division multiplex access method (CDMA) and
an orthogonal frequency division multiplexing method (OFDM).
[0011] Differences in communication rules, i.g., protocols, of
integrated circuits means that predetermined rules for conducting
data communication are different. When the protocols are different,
processing rules of central processing units (CPUs) formed in the
thin film integrated circuits are different.
[0012] As for the operation method of the above described thin
semiconductor device, a reader/writer communicates with plural thin
film integrated circuits, information is written in a memory by
transmitting a signal to at least one of the plurality of thin film
integrated circuits, and it is determined which of the plurality of
thin film integrated circuits communicates by the information
written in the memory.
[0013] As described above, by the communication mode of the thin
film integrated circuit and the reader/writer, it is possible to
determine which of thin film integrated circuits is communicated
with. Therefore, access to the memory can be limited.
[0014] According to the present invention, a thin semiconductor
device in which a thin film integrated circuit is mounted includes
an ID card typified by a credit card, an ID tag used for
merchandise management, and an ID chip mounted on an article.
[0015] According to the present invention, the security of a thin
semiconductor device can be improved. According to the present
invention, a new operation method of a thin semiconductor device
can be provided. In the operation method of the present invention,
the memory can be a nonvolatile memory. Using the nonvolatile
memory that can write to only once can prevent falsification. The
nonvolatile memory can further enhance the security of a thin
semiconductor device.
[0016] In the operation method of the present invention, the memory
can be a rewritable memory. Thus, the thin film integrated circuit
can be reused to contribute to lower cost of thin semiconductor
devices.
[0017] Since a thin film integrated circuit of the present
invention is formed over an insulating substrate, it has fewer
limitations on the shape of a mother substrate as compared with an
IC chip formed by using a circular silicon wafer. Therefore,
mass-productivity of thin film integrated circuits is enhanced and
thus thin film integrated circuits can be mass-produced. As the
result thereof, cost reduction of thin film integrated circuits can
be expected. A thin film integrated circuit formed at extremely low
unit cost can generate big profits by the reduction of unit
costs.
BRIEF DESCRIPTION OF DRAWINGS
[0018] In the accompanying drawings:
[0019] FIG. 1 shows a mode of a thin semiconductor device;
[0020] FIG. 2 is a flow chart showing an operation method of a thin
semiconductor device;
[0021] FIG. 3 shows key information of a thin semiconductor
device;
[0022] FIG. 4 shows a mode of a thin semiconductor device;
[0023] FIG. 5 is a flow chart showing an operation method of a thin
semiconductor device;
[0024] FIGS. 6A and 6B each show key information of a thin
semiconductor device;
[0025] FIG. 7 is a flow chart showing an operation method of a thin
semiconductor device;
[0026] FIGS. 8A and 8B each show key information of a thin
semiconductor device;
[0027] FIGS. 9A to 9E each show an operation method of a thin
semiconductor device;
[0028] FIGS. 10A to 10C each show steps of manufacturing a thin
semiconductor device;
[0029] FIGS. 11A to 11C each show steps of manufacturing a thin
semiconductor device;
[0030] FIGS. 12A to 12C each show steps of mounting a thin
semiconductor device;
[0031] FIG. 13 shows a mode of a thin semiconductor device;
[0032] FIG. 14 shows a mode of a thin semiconductor device;
[0033] FIG. 15 shows a mode of a thin semiconductor device;
[0034] FIGS. 16A and 16B each show an article provided with thin
film integrated circuits;
[0035] FIG. 17 shows an article provided with thin film integrated
circuits;
[0036] FIG. 18 shows an article provided with thin film integrated
circuits; and
[0037] FIGS. 19A and 19B each show steps of manufacturing a thin
semiconductor device.
BEST MODE FOR CARRYING OUT THE INVENTION
[0038] Embodiment Modes according to the present invention will
hereinafter be described with reference to the accompanying
drawings. The present invention can be carried out in many
different modes, and it is easily understood by those skilled in
the art that modes and details herein disclosed can be modified in
various ways without departing from the spirit and the scope of the
present invention. It should be noted that the present invention
should not be interpreted as being limited to the description of
the embodiment modes to be given below. Note that the same
reference numerals are given to the same portions or the portions
having the same function in all drawings, and the description
thereof is not repeated.
Embodiment Mode 1
[0039] Embodiment Mode 1 describes an operation method of a thin
semiconductor device in which a plurality of thin film integrated
circuits are mounted.
[0040] As shown in FIG. 1, in a thin semiconductor device of this
embodiment mode, a first thin film integrated circuit 301a, a
second thin film integrated circuit 301b and a third thin film
integrated circuit 301c that share an antenna 300, are connected to
an electronic key 305 and a control circuit 306 through a gate
circuit 304. The electronic key 305 may be formed by using a
nonvolatile memory. This is because falsification of the electronic
key itself and abuse accompanied with it can be prevented. A memory
circuit 307 includes a first memory 307a and a second memory 307b,
and is connected to the control circuit 306. Note that the first
memory 307a and the second memory 307b are shown for convenience;
however, a region for forming the memories is not necessarily
divided in the actual memory circuit 307. The antenna 300, the
control circuit 306, and the memory circuit 307 are each connected
to a power supply circuit 308.
[0041] An operation method of such a thin semiconductor device will
be described by using a flow chart. As shown in FIG. 2, a signal is
received from an antenna 300, and data (key information) 1 to be an
electronic key is given to a first thin film integrated circuit
301a by the electronic key 305 (corresponding to Reception 1).
Similarly, a signal is received from the antenna 300, and key
information 2 is given to a second thin film integrated circuit
301b by the electronic key 305 (corresponding to Reception 2).
Similarly, a signal is received from the antenna 300, and key
information 3 is given to a third thin film integrated circuit 301c
by the electronic key 305 (corresponding to Reception 3). This key
information 1 to 3 can be rewritten, i.e., updated by receiving any
key information of the first to third thin film integrated
circuits.
[0042] Writing or reading information of either the first memory
307a or the second memory 307b can be selected by the key
information 1 to 3. Note that reading out information from a memory
is referred to as reading, writing information in a memory is
referred to as writing, and reading and writing are collectively
referred to as access to a memory.
[0043] In other words, writing to and reading from the first and
second memories can be controlled by the control circuit depending
on the state of the key information. In addition, if access to the
memory is rejected because of inconsistence with the key
information, an error signal may be sent or an error sound may be
emitted. Transmission to/reception from the thin film integrated
circuit itself may be set to be impossible (not allowed)
accompanying with the transmission of the error signal. In
addition, when reading from the first or the second memory is
conducted, the key information is referred and only when it is
consistent, a signal that reading is possible (allowed) is
sent.
[0044] After reading of the first or the second memory is
conducted, information is transmitted to a first thin film
integrated circuit 301a, a second thin film integrated circuit
301b, and a third thin film integrated circuit 301c. At this time,
the key information is referred to determine which one of the thin
film integrated circuits is to receive a signal. In other words,
the control circuit controls so that predetermined information is
transmitted through the thin film integrated circuit that has
received a signal.
[0045] Next, key information is described specifically. Whether
writing to the first or the second memory or the reading from the
first or the second memory is possible or impossible (allowed or
not allowed) is controlled by "0" or "1". For example, as shown in
FIG. 3, if writing to the second memory is not allowed, the key
information is "0100". In addition, if writing to and reading from
the first memory are not allowed, the key information is "1010". If
writing to the first memory is not allowed, the key information is
"1000". If writing to and reading from the second memory are not
allowed, the key information is "0101". If writing to and reading
from the first and the second memories are rejected, the key
information is "1111". The key information in the initial state is
"0000". In this way, writing to and reading from the first and the
second memories can be controlled. Note that, in FIG. 3, "-"
indicates a state that transmission/reception is not conducted, and
"*" indicates a state that transmission to/reception from a thin
film integrated circuit is prohibited.
[0046] Such states are controlled by a signal received by the first
to the third thin film integrated circuits. For example, when a
reader/writer sends out a signal "0100", only the first thin film
integrated circuit receives the signal. Specifically, the
reader/writer device may use the communication rule, a unique
frequency, or a unique communication means that is unique for the
first thin film integrated circuit, to transmit a signal "0100".
The unique communication rule can adopt, for example, a unique
protocol. The unique frequency can adopt any of a sub millimeter
wave (300 GHz to 3 THz), an extremely-high-frequency wave (EHF) (30
GHz to 300 GHz), a super-high-frequency wave (SHF) (3 GHz to 30
GHz), an ultra-high-frequency wave (UHF) (300 MHz to 3 GHz), a
very-high-frequency (VHF) (30 MHz to 300 MHz), a high-frequency
wave (HF) (3 MHz to 30 MHz), a medium-frequency wave (MF) (300 KHz
to 3 MHz), a long frequency wave (LF) (30 KHz to 300 KHz) and a
very-long frequency wave (VLF) (3 KHz to 30 KHz). The specific
frequency can adopt any of 135 KHz, 6.78 MHz, 13.56 MHz, 27.125
MHz, 40.68 MHz, 433.92 MHz, 869.0 MHz, 915.0 MHz, 2.45 GHz, 5.8 GHz
and 24.125 GHz. Further, since the frequency is attributed to the
length of an antenna, the length of an antenna of a thin film
integrated circuit is set. In addition, a digital modulation system
or an analog modulation system can be adopted as the unique
communication means. The digital modulation system can be any of
amplitude shift keying (ASK), frequency shift keying (FSK) and
phase shift keying (PSK). The analog modulation system can be any
of amplitude modulation (AM), frequency modulation (FM) and phase
modulation (PM). Additionally, the communication means can adopt
either one-way communication or two-way communication. Further, it
can adopt any of a space division multiplex access method (SDMA), a
polarization division multiplex access method (PDMA), a
frequency-division multiplex access method (FDMA), a time-division
multiplex access method (TDMA), a code division multiplex access
method (CDMA) and an orthogonal frequency division multiplexing
method (OFDM).
[0047] Then, writing to the first memory is conducted. When the
writing to the first memory is done, a signal "0100" is transmitted
from a reader device and reading from the first memory can be
conducted. At the same time, reading from the second memory becomes
possible, but no information can reading, since writing to the
second memory has not been conducted. In other words, when the
first integrated circuit receives the signal "0100", writing to and
reading from the first memory only can be conducted.
[0048] Next, when the thin semiconductor device receives a signal
"1010", only the second thin film integrated circuit receives the
signal. Specifically, the reader/writer may use a unique
communication rule, a unique frequency, a unique communication
means of the second thin film integrated circuit to transmit the
signal "1010". These unique frequency, communication means,
communication rule can be selected in the same way as transmission
to the first thin film integrated circuit.
[0049] Then, writing to the first memory is not allowed, and
writing to the second memory is allowed. Simultaneously, reading
from the first memory is not allowed and reading from the second
memory is allowed. In other words, when the second thin film
integrated circuit receives a signal "1010" writing to and reading
from the second memory only can be conducted.
[0050] Next, when the thin semiconductor device receives a signal
"1000", only the second thin film integrated circuit receives the
signal. In addition, the first thin film integrated circuit may not
be allowed to receive a signal. Specifically, the reader/writer
device may use a unique communication rule, a unique frequency, a
unique communication means of the second thin film integrated
circuit to transmit the signal "1000". These unique frequency,
communication means, communication rule can be selected in the same
way as transmission to the first thin film integrated circuit.
[0051] In this way, the first thin film integrated circuit is not
allowed to receive a signal, thereby controlling such that reading
from the first memory cannot be conducted. In other words,
information of the first memory is not read by a third person. Note
that setting is done so that the first memory can be reading by a
signal transmitted from a reader/writer of a specific manufacturer
such as a manufacturer and seller or a manager of a thin
semiconductor device. Consequently, information can be read out by
a principal or a specific person in a specific circumstance without
being reading by a third person, in general.
[0052] Next, when the thin semiconductor device receives a signal
"0101", the first thin film integrated circuit receives the signal,
and further, it is preferable that the second thin film integrated
circuit cannot receive the signal. Specifically, the reader/writer
may use a unique communication rule, a unique frequency, a unique
communication means of the first thin film integrated circuit to
transmit the signal "0101". These unique frequency, communication
means, communication rule can be selected as described above.
[0053] In this way, the second thin film integrated circuit is not
allowed to receive a signal, thereby controlling such that reading
from the second memory cannot be conducted. In other words,
information of the second memory is not read by a third person.
Note that setting is done so that the second memory can be reading
by a signal transmitted from a reader/writer of a specific
manufacturer such as a seller of a thin semiconductor device.
Consequently, information can be read out by a principal or a
specific person in a specific circumstance without being reading by
a third person, in general.
[0054] Next, when the thin semiconductor device receives a signal
"1111", a third thin film integrated circuit receives the signal.
In addition, the first and the second thin film integrated circuits
may not be allowed to receive a signal. Specifically, the
reader/writer device may use a unique communication rule, a unique
frequency, a unique communication means of the third thin film
integrated circuit to transmit the signal "1111". These unique
frequency, communication means, communication rule can be selected
in the same way as transmission to the first thin film integrated
circuit.
[0055] In this way, the first and the second thin film integrated
circuits are not allowed to receive a signal and thus reading from
the first and the second memories cannot be conducted. In other
words, information of the first and the second memories is not read
by a third person. Note that setting is done so that the first and
the second memories can be reading by receiving key information
from the third thin film integrated circuit by a signal transmitted
from a reader/writer device of a specific manufacturer such as a
seller of a thin semiconductor device. Consequently, a principal or
a specific person can read information from the first or the second
memory.
[0056] In this manner, it is possible to control reading from and
writing to a memory circuit by making it impossible for a thin film
integrated circuit to receive a signal when the thin semiconductor
device receives the signal. As the result thereof, the security can
be enhanced. Private information may be input into a memory circuit
in which reading is limited.
[0057] In this embodiment mode, it is preferable to control
reception by unique protocols of the first to the third thin film
integrated circuits, since an antenna is shared. However, antennas
may be provided for each thin film integrated circuit and reception
of the first to the third thin film integrated circuits can be
controlled by a frequency transmitted from the reader/writer. In
addition, reception of the first to the third thin film integrated
circuits can be controlled by a communication means with the
reader/writer.
[0058] As described above, by using the plurality of thin film
integrated circuits, it is possible to control key information,
preferably to update key information, and further control of
writing to and reading from the memory circuits. Consequently,
information leakage to a third person can be prevented and the
security can be enhanced.
[0059] In this embodiment mode, three thin film integrated
circuits, two memories and one antenna are used; however, the
present invention is not limited thereto.
Embodiment Mode 2
[0060] In Embodiment Mode 2, an operation method of a thin
semiconductor device is described. The operation method is
different from that of Embodiment Mode 1 in an update method of key
information. As shown in FIG. 4, in the thin semiconductor device
of this embodiment mode, a first thin film integrated circuit 301a
and a second thin film integrated circuit 301b that share an
antenna 300, are connected to an electronic key 305 and a control
circuit 306 through a gate circuit 304. The electronic key 305 may
be formed from a nonvolatile memory. This is because falsification
of the electronic key itself and abuse accompanied with it can be
prevented. A memory circuit 307 is connected to the control circuit
306. Note that the memory circuit 307 may include a first memory
307a and a second memory 307b. In addition, the antenna 300, the
control circuit 306 and the memory circuit 307 are each connected
to a power supply circuit 308.
[0061] An operation method of the above described thin
semiconductor device is described by using a flow chart shown in
FIG. 5. Data is input to the electronic key 305 by a first
reception mode (Reception 1) and key information is given. Data is
input to the electronic key 305 by a second reception mode
(Reception 2) and key information is given. For example, control is
done such that only the first thin film integrated circuit is
operated by the first reception mode and only the second thin film
integrated circuit is operated by the second reception mode.
[0062] The reception mode can be selected by employing different
frequencies, e.g., f1 and f2, or different protocols e.g., P1 and
P2 as described above.
[0063] Key information can be given such that, for example, "01" is
obtained by the first reception mode (the lower-order bit is 1,
namely, Data=*1) and "10" is obtained by the second reception mode
(the higher-order bit is 1, namely, Data=1*).
[0064] Depending on this, for example, as shown in FIG. 6A, the
first reception mode can adopt a frequency f1, a protocol P1 and
key information "01". The second reception mode can adopt a
frequency f2, a protocol P2 and key information "10".
[0065] Writing to or reading from the memory circuit 307 is
controlled by the key information. For example, if key information
for writing becomes possible, writing to the memory circuit is
allowed. If key information for reading becomes possible, reading
from the memory circuit is allowed. If the key information becomes
impossible, an error signal is transmitted. Additionally,
transmission to/reception from the first and the second thin film
integrated circuits may be prohibited.
[0066] For example, as shown in FIG. 6B, reading from and writing
to the memory circuit become possible when the key information is
"00", namely, in an initial state. When the key information is
"01", reading from the memory circuit is allowed, and writing is
not allowed. When the key information is "10", reading from the
memory circuit is not allowed, and writing is allowed. When the key
information is "11", reading from and writing to the memory circuit
are not allowed. In this manner, it is possible to set key
information, and reading from and writing to the memory
circuit.
[0067] If an electronic key is formed by using two nonvolatile
memories, key information is "01", "10" or "11", but key
information can be formed by using n-pieces of nonvolatile
memories. Consequently, as shown in a flow chart of FIG. 5, key
information of the electronic key can be updated. For example, if
four nonvolatile memories are used, even after "11" is obtained,
"1100" is made and key information becomes "1101" or "1111" to
control reading from and writing to the memory circuit.
[0068] After reading of the memory circuit is conducted,
information is sent to the first thin film integrated circuit C1 or
the second thin film integrated circuit C2. At this time, based on
the key information, it is determined which one of thin film
integrated circuits C1 and C2 receives information.
Embodiment Mode 3
[0069] Embodiment Mode 3 describes a communication system
(communication mode) between a thin film integrated circuit and a
reader/writer by using a flow chart shown in FIG. 7.
[0070] A thin semiconductor device is brought close to a
reader/writer. At this time, a thin film integrated circuit C1 of
the thin semiconductor device receives a signal. Thus, writing or
the like to a memory circuit in the thin semiconductor device is
conducted. Thereafter, information is sent from the thin film
integrated circuit C1 to the reader/writer. Then, the reader/writer
determines whether to communicate with another thin film integrated
circuit Cn.
[0071] After that, communication with another thin film integrated
circuit Cn is conducted, information is sent to the reader/writer
from the thin film integrated circuit Cn. Thereafter, the
reader/writer determines whether to communicate with another thin
film integrated circuit.
[0072] Whether communication with another thin film integrated
circuit is conducted or not may be determined depending on the thin
film integrated circuit from which the reader/writer receives a
signal. Information of the next thin film integrated circuit to be
communicated with may be given to the reader/writer by the thin
film integrated circuit which has conducted communication. When the
number of communication with other thin film integrated circuits is
increased, the security can be enhanced.
[0073] Communication between the thin semiconductor device and the
reader/writer can adopt any of a sub millimeter wave (300 GHz to 3
THz), an extremely-high-frequency wave (EHF) (30 GHz to 300 GHz), a
super-high-frequency wave (SHF) (3 GHz to 30 GHz), an
ultra-high-frequency wave (UHF) (300 MHz to 3 GHz), a
very-high-frequency (VHF) (30 MHz to 300 MHz), a high-frequency
wave (HF) (3 MHz to 30 MHz), a medium-frequency wave (MF) (300 KHz
to 3 MHz), a long frequency wave (LF) (30 KHz to 300 KHz) and a
very-long frequency wave (VLF) (3 KHz to 30 KHz). The specific
frequency can adopt any of 135 KHz, 6.78 MHz, 13.56 MHz, 27.125
MHz, 40.68 MHz, 433.92 MHz, 869.0 MHz, 915.0 MHz, 2.45 GHz, 5.8 GHz
and 24.125 GHz. As a result, the reader/writer can transmit a
signal to at least one of the plural thin film integrated
circuits.
[0074] The communication between the thin semiconductor device and
the reader/writer may adopt a digital modulation system. The
digital modulation system is any of amplitude shift keying (ASK),
frequency shift keying (FSK) and phase shift keying (PSK). As a
result, the reader/writer can transmit a signal to at least one of
the plural thin film integrated circuits.
[0075] The communication between the thin semiconductor device and
the reader/writer may adopt an analog modulation system. The analog
modulation system is any of amplitude modulation (AM), frequency
modulation (FM) and phase modulation (PM). As a result, the
reader/writer can transmit a signal to at least one of the plural
thin film integrated circuits.
[0076] The communication between the thin semiconductor device and
the reader/writer may adopt either one-way communication or two-way
communication. Further, it can adopt any of a space division
multiplex access method (SDMA), a polarization division multiplex
access method (PDMA), a frequency-division multiplex access method
(FDMA), a time-division multiplex access method (TDMA), a code
division multiplex access method (CDMA) and an orthogonal frequency
division multiplexing method (OFDM).
[0077] The communication between the thin semiconductor device and
the reader/writer can adopt different protocols. As a result, the
reader/writer can transmit a signal to at least one of the plural
thin film integrated circuits.
[0078] By repeating the above described operations, the thin
semiconductor device can communicate with the reader/writer. At
this time, each thin film integrated circuit may mount an antenna
or share an antenna. When an antenna is mounted on each thin film
integrated circuit, frequencies received by each thin film
integrated circuit may be different.
[0079] As described in this embodiment mode, the operation method
of a thin semiconductor device can be set, for example, by the
communication between a thin film integrated circuit of this
embodiment mode and a reader/writer.
Embodiment Mode 4
[0080] Embodiment Mode 4 describes a mode of applying to food
distribution a thin semiconductor device mounting a plurality of
thin film integrated circuits as a tag, so-called ID tag, and an
operation method thereof.
[0081] As shown in FIG. 8A, data of key information is set "0000"
(initial value), "0001", "0011", "0111" or "1111". As described in
the above embodiment mode, transmission to/reception from a thin
film integrated circuit, namely, access to a memory, can be limited
by the key information data.
[0082] As shown in FIG. 8B, this key information data can control
"0" and "1" sequentially by operations (1) (2) (3) and (4). The
operations (1) (2) (3) and (4) can be controlled, for example,
depending on which thin film integrated circuit receives a signal,
as described in the above embodiment mode.
[0083] The thin semiconductor device having such key information
data includes a first thin film integrated circuit C1, a second
thin film integrated circuit C2, a third thin film integrated
circuit C3, and a fourth thin film integrated circuit C4, and a
first memory M1 and a second memory M2 that are each accessible, as
shown in FIGS. 9A to 9E. As shown in FIG. 9A, only the first thin
film integrated circuit C1 is allowed to be in an accessible state
(state where a signal of In or Out is received). The first thin
film integrated circuit C1 can perform writing or reading to the
first memory M1. For example, key information is set "0001". For
instance, such an operation to the thin semiconductor device is
conducted by a reader/writer in a food manufacturing and processing
factory, and basic data of a product such as a production area, a
producer, a processing date, and an expiration date is written into
the first memory M1. Before shipment, it is confirmed whether the
basic data is accurately input into the first memory M1.
[0084] After that, when transmission to/reception from the second
thin film integrated circuit C2 is tried, transmission to/reception
from the first thin film integrated circuit C1 is prohibited as
shown in FIG. 9B. For example, key information is set "0011". Note
that prohibition of transmission to/reception from the first thin
film integrated circuit C1 may be set in shipping from the
manufacturing factory. As the result of the prohibition of
transmission to/reception from the first thin film integrated
circuit C1, writing to the first memory M1 is prohibited, only
reading from the first memory M1 is allowed, and the second thin
film integrated circuit C2 can be controlled so that writing or
reading from the second memory M2 is allowed. For example, such an
operation to a thin semiconductor device is performed by a
reader/writer in distribution process. Then, falsification of basic
data written in the manufacturing factory is not done in
distribution process, and data necessary in the distribution
process, such as delivery address or the number of deliveries, is
written in the second memory M2. Before delivering, it can be
confirmed whether data required in distribution process is input
precisely to the second memory M2.
[0085] Then, when transmission to/reception from the third thin
film integrated circuit C3 is tried, transmission to/reception from
the second thin film integrated circuit C2 is prohibited as shown
in FIG. 9C. For example, key information is set "0111". Note that
prohibition of transmission to/reception from the second thin film
integrated circuit C2 may be set in delivering from the
distribution process. As the result of the prohibition of
transmission to/reception from the second thin film integrated
circuit C2, writing to the first and second memories M1 and M2 is
prohibited, and only reading from the first and second memories M1
and M2 is possible. For example, such an operation to a thin
semiconductor device is performed by using a reader/writer in a
shop. Then, it is impossible to, in a shop, conduct falsification
of data written in a manufacturing factory and a distribution
process. In a shop, such written data may only be confirmed.
[0086] When a price of an article or the like is written, the price
may be written in a bar code reader, since the price changes. A
means for writing such as a memory or a barcode reader can be
selected depending on data or content to be written.
[0087] Then, when transmission to/reception from the fourth thin
film integrated circuit C4 is tried, transmission to/reception from
the third thin film integrated circuit C3 is prohibited as shown in
FIG. 9D. For example, key information is set "1111". Note that
prohibition of transmission to/reception from the third thin film
integrated circuit C3 may be set at the time of purchase in the
shop. As the result of the prohibition of transmission and
reception to the third thin film integrated circuit C3, writing to
and reading from the first and second memories M1 and M2 are
prohibited. For example, such an operation to a thin semiconductor
device is performed by using a reader/writer in a shop,
specifically, a system provided for a register. Then, falsification
of data written in the first and second memories M1 and M2 cannot
be conducted by a consumer or the like. Such written data may be
only confirmed by a customer or the like in the shop.
[0088] Date written in the first memory M1 and the second memory M2
outside a shop can be read out by a consumer by controlling the
number of thin film integrated circuits or memories, and a state in
which transmission/reception are prohibited.
[0089] The thin semiconductor device, as shown in FIG. 9E, in which
access to the first memory M1 and the second memory M2 is
prohibited is preferably collected for recycling. For example,
after purchasing an article, the thin semiconductor device may be
collected at a cash register or the like. Since a customer or the
like cannot read from the first memory M1 and the second memory M2
due to the fourth thin film integrated circuit C4, it may be
collected at a cash register. In such collected thin semiconductor
devices collected in this manner, information written to the first
memory M1 and the second memory M2 is deleted. Thus, the first
memory M1 and the second memory M2 may be formed from an EEPROM or
the like, and information therein can be deleted by a physical
means such as ultraviolet irradiation or a chemical process.
[0090] Note that, if information is not required to delete, the
first memory M1 and the second memory M2 may be formed from a
nonvolatile memory, which also leads to prevention of
falsification.
[0091] In this embodiment mode, four thin film integrated circuits
and two memories are used. However, the present invention is not
limited thereto. For example, a memory can be shared or a memory
can be formed in a thin film integrated circuit.
[0092] Such a thin semiconductor device in which plural thin film
integrated circuits are mounted can prevent falsification of
information about an article which passes through a large number of
processes, and thus security can be improved.
[0093] In addition, a thin film integrated circuit of the present
invention can be manufactured at a lower cost as compared with a
conventional IC chip. Thus, a plurality of thin film integrated
circuits can be mounted without increasing the cost of a thin
semiconductor device.
Embodiment Mode 5
[0094] Embodiment Mode 5 describes a manufacturing method of a
plurality of thin film integrated circuits.
[0095] As shown in FIG. 10A, a separation layer 102, and a thin
film transistor layer 103 (referred to as a TFT layer) having a
semiconductor film as an active region are formed sequentially over
an insulating substrate 100 to form a plurality of thin film
integrated circuits 101. FIGS. 10B and 10C are cross-sectional
views of a-b and c-d from FIG. 10A, respectively.
[0096] A glass substrate such as a barium borosilicate glass or an
alumino borosilicate glass, a quartz substrate and the like are
cited for the insulating substrate 100. In addition, a substrate
made of plastic typified by polyethylene-terephthalate (PET),
polyethylene naphthalate (PEN) or polyether sulfone (PES), or
synthetic resin having flexibility such as acrylic is cited as
other substrates having an insulating surface. In addition, a metal
such as stainless or a semiconductor substrate whose surface is
formed with an insulating film such silicon oxide or silicon
nitride can be used. A shape of a mother substrate is not limited
and lower cost of a thin film integrated circuit can be achieved by
using such an insulating substrate 100, as compared with the case
of forming an IC chip from a circular silicon wafer.
[0097] The separation layer 102 may include silicon, and the
structure of the separation layer may be any one of an amorphous
semiconductor, a semiamorphous semiconductor (also referred to as
SAS) with an amorphous state and a crystalline state are mixed, and
a crystalline semiconductor. Note that SAS contains a
microcrystalline semiconductor in which crystal grains of 0.5 nm to
20 nm in size in an amorphous semiconductor film. Such a separation
layer 102 can be formed by a sputtering method, a plasma CVD method
or the like. The separation layer 102 may be 30 nm to 1 .mu.m
thick, or can be 30 nm thick or less as long as a film formation
apparatus of the separation layer 102 permits.
[0098] In addition, the separation layer 102 may be added with an
element such as phosphorus or boron. Further, the element may be
activated by heating or the like. By adding such an element, the
reaction speed of the separation layer 102, that is, an etching
rate can be improved.
[0099] In this embodiment mode, SAS that is 30 nm to 1 .mu.m thick,
preferably 30 nm to 50 nm thick is used as the separation layer
102; however, other materials described above may be used.
[0100] At this time, the separation layer 102 may be selectively
formed. For example, the separation layer 102 is not formed in the
periphery of the insulating substrate 100. A TFT layer 103 is not
parted due to selectively forming the separation layer 102, even
after removing the separation layer. In other words, the TFT layer
is integrated. As a method for forming the separation layer 102
selectively, the periphery of the insulating substrate 100 is
etched, after a mask is arranged to cover the periphery of the
insulating substrate 100 and the separation layer 102 is formed, or
the separation layer 102 is formed over the entire surface of the
insulating substrate 100.
[0101] Note that the TFT layer 103 includes thin film transistors
128n and 128p including a base insulating film, a semiconductor
film 124 which has been patterned into a desired shape, a
conductive film 126 functioning as a gate electrode (hereinafter,
referred to as a gate electrode), which is formed through an
insulating film 125 (hereinafter, a gate insulating film) serving
as a gate insulting film. The semiconductor is 0.2 .mu.m thick or
less, typically 40 nm to 170 nm thick, preferably 50 nm to 150 nm
thick. Note that the thin film transistor may have a single drain
structure, an LDD (Lightly Doped Drain) structure, or a GOLD
(Gate-drain Overlapped LDD) structure. In addition, the
semiconductor film includes a channel formation region and an
impurity region (including a source region, a drain region, a GOLD
region, and an LDD region). The n-channel thin film transistor 128n
and the p-channel thin film transistor 128p can be distinguished by
a conductivity of the added impurity element. In addition, so as to
prevent the channel from becoming shorter as the channel formation
region becomes more minute, it is preferable to have a so-called
sidewall structure by forming an insulator on a side of the gate
electrode. A low concentration impurity region is formed under the
insulator. A wiring 130 which is formed to be connected to each
impurity region is included in the TFT layer 103.
[0102] The base insulating film formed over the separation layer
102 may have a single layer structure or a lamination structure of
insulating films containing oxygen or nitrogen, such as silicon
oxide (SiO.sub.x), silicon nitride (SiN.sub.x), silicon oxynitride
(SiO.sub.xN.sub.y) (x>y) and silicon nitride oxide
(SiN.sub.xO.sub.y) (x>y) (x, y=1, 2 . . . ) so that the TFT
layer 103 is not be etched. This is because a sufficient selection
ratio with the separation layer 102 to an etching gas can be
obtained.
[0103] Thus, the base insulating film may have a lamination
structure. In this embodiment mode, the base insulating film
includes a first insulating film 121, a second insulating film 122,
and a third insulting film 123. For example, a silicon oxide film
as the first insulating film, a silicon oxynitride film as the
second insulating film, and a silicon oxide film as the third
insulating film are employed, respectively. In consideration of
impurity diffusion from the insulating substrate 100 or the like, a
silicon oxynitride film is preferably used; however, there is a
concern that the silicon oxynitride film is low in adhesion to the
separation layer and the semiconductor film. Thus, a silicon oxide
film having high adhesion to the separation layer, the
semiconductor film and the silicon oxynitride film, is
provided.
[0104] The semiconductor film 124 may have an amorphous
semiconductor, SAS in which an amorphous state and a crystalline
state are mixed, or a crystalline semiconductor.
[0105] In this embodiment mode, an amorphous semiconductor film is
formed and then a crystalline semiconductor film crystallized by a
heat treatment is formed. As the heat treatment, a heating furnace,
laser irradiation or irradiation of light emitted from a lamp
(hereinafter, lamp annealing) instead of laser light, or a
combination thereof can be used.
[0106] In the case of laser irradiation, a continuous wave laser
beam (CW laser beam) or a pulsed oscillation laser beam (pulsed
laser beam) can be used. As the laser beam, a beam emitted from one
or plural kinds of an Ar laser, a Kr laser, an excimer laser, a YAG
laser, a Y.sub.2O.sub.3 laser, a YvO.sub.4 laser, a YLF laser, a
YAlO.sub.3 laser, a glass laser, a ruby laser, an alexandrite
laser, a Ti: sapphire laser, a copper vapor laser, and a gold vapor
laser, can be used. A laser beam having a fundamental wave of such
lasers or a second to a fourth harmonic of the fundamental wave is
irradiated to obtain a crystal with a large grain size. Typically,
for instance, the second harmonic (532 nm) or the third harmonic
(355 nm) of an Nd:YVO.sub.4 laser (fundamental wave with 1064 nm)
can be used. In this case, the power density of about 0.01 to 100
MW/cm.sup.2 (preferably, 0.1 to 10 MW/cm.sup.2) is required. The
scanning rate is approximately set about 10 to 2,000 cm/sec to
irradiate the semiconductor film.
[0107] At this time, for example, an optical system as shown in
FIG. 19A is employed to conduct crystallization using a CW laser.
First, a CW laser beam emitted form a laser oscillator 290 is
elongated by an optical system 291 and then processed into a linear
shape. Specifically, when the laser beam passes through a
cylindrical lens or a convex lens of the optical system 291, the
laser beam can be processed into a linear shape. At this time, it
may be processed so that the length of the longitudinal axis of the
beam spot is 200 to 350 .mu.m.
[0108] After that, the laser beam that is processed into a linear
shape enters a semiconductor film 124 through a galvanometer mirror
293 and an f .theta. lens 294. At this time, the linear laser beam
is adjusted to form a laser spot 282 having a desired size on the
semiconductor film. In addition, the shape of the laser spot 282
can be constant on the irradiated surface by the f .theta. lens
294, irrespective of an angel of the galvanometer mirror.
[0109] At this time, the galvanometer mirror is oscillated by a
device for controlling oscillation of the galvanometer mirror
(control device) 296, in other words, the angle of the galvanometer
mirror is changed, and the laser spot 282 moves in one direction
(for example, in the X-axis direction in FIG. 19A). For example,
when the galvanometer mirror oscillates in half cycle, a laser beam
moves a fixed distance in the X-axis direction on the semiconductor
film (forth).
[0110] After that, the semiconductor film 124 moves in the Y-axis
direction by an X-Y stage 295. Similarly, the laser spot moves in
the X-axis direction on the semiconductor film by the galvanometer
mirror (back). By such back and forth movement of the laser beam,
the laser spot moves along a path 283, thereby conducting laser
irradiation.
[0111] As shown in FIG. 19B, laser irradiation is performed so that
movement direction of carriers of a thin film transistor is along
the movement direction (a scanning direction) of the laser beam in
the X-axis direction. For example, in the case of the semiconductor
film 124 having a shape shown in FIG. 19B, a source region 124 (s),
a channel formation region 124 (c), and a drain region 124 (d) to
be formed in the semiconductor film are arranged so as to be
parallel with the movement direction in the X-axis direction
(scanning direction) of the laser beam. Consequently, mobility of a
thin film transistor can be increased since grain boundaries that
are crossed by carriers can be reduced or eliminated.
[0112] In addition, an incident angle .theta. of the laser beam may
be set 0.degree.<.theta.<90.degree. to the semiconductor
film. As a result, interference of the laser beam can be
prevented.
[0113] A laser beam having a fundamental wave of a continuous wave
laser and a laser beam having a harmonic of a continuous wave laser
may be emitted. Alternatively, a laser beam having a fundamental
wave of a continuous wave laser and a laser beam having a harmonic
of a pulsed laser may be emitted. By using plural laser beams,
energy can be compensated.
[0114] A pulsed laser beam can be used, which oscillates a laser
with such an oscillation frequency that can emit the next pulsed
laser beam, until the semiconductor film is melted due to
irradiation of a laser beam and then solidified. By oscillating a
laser beam with the frequency, crystal grains grown continuously in
the scanning direction can be obtained. A specific oscillation
frequency of a laser beam is 10 MHz or more, and this is a
remarkably higher frequency band than a frequency band of several
tens of Hz to several hundreds of Hz, which are employed
generally.
[0115] Note that irradiation of a laser beam may be conducted in an
inert gas atmosphere such as a rare gas or nitrogen. Thus,
roughness on the semiconductor surface due to the irradiation of a
laser beam can be suppressed, the planarity can be enhanced, and
fluctuation on a threshold value generated due to variation of
interface state density can be suppressed.
[0116] A microcrystalline semiconductor film is formed by using
SiH.sub.4 and F.sub.2 or SiH.sub.4 and H.sub.2, and then laser
irradiation described above is performed to crystallize the
microcrystalline semiconductor film.
[0117] In the case of using a heating furnace as another heat
treatment, an amorphous semiconductor film is heated for 2 to 20
hours at 500 to 550.degree. C. At this time, the temperature may be
set at multiple stages in the range of 500 to 550.degree. C. in
order to make the temperature higher gradually. By the initial
low-temperature heat treatment, hydrogen or the like in the
amorphous semiconductor film comes out, and as the result,
so-called dehydrogenation which can reduce film-roughness generated
in the crystallization, can be conducted. Further, it is preferable
that a metal element for promoting crystallization, such as Ni, is
formed on an amorphous semiconductor film, since the heat
temperature can be reduced. Even during crystallization when using
such a metal element is conducted, it may be heated at 600 to
950.degree. C.
[0118] However, when such a metal element is formed, there is
concern that the metal element adversely affects electric
characteristics of a semiconductor element, and thus a gettering
step for reducing or removing the metal element is needed. For
example, the metal element may be gettered using an amorphous
semiconductor film as a gettering sink.
[0119] In addition, a crystalline semiconductor film may be formed
directly on a surface. In this case, a crystalline semiconductor
film can be formed directly on a surface using a fluorine-based gas
such as GeF.sub.4 or F.sub.2 and a silane-based gas such as
SiH.sub.4 or Si.sub.2H.sub.6 with heat or plasma. When a
crystalline semiconductor film is directly formed and a high
temperature treatment is needed, a quartz substrate having a
favorable heat resistance may be used.
[0120] It is considered that the separation layer 102 may be
affected by the step of heating the semiconductor film. For
example, energy may reach the separation layer 102, if a heat
treatment using a heating furnace or laser irradiation using a
wavelength of 532 nm is conducted. Consequently, the separation
layer 102 is also crystallized in some cases. The reaction speed
can also be improved by the crystallization state of the separation
layer 102.
[0121] On the other hand, a structure of the base insulating film
can be selected so that energy of a laser beam does not reach the
separation layer 102, so as to crystallize the semiconductor film
efficiently. For example, the material, film-thickness and
lamination order of the base insulating film may be selected.
[0122] A semiconductor film formed by any one of the
above-described means contains more hydrogen as compared with an IC
chip formed from a silicon wafer. Specifically, the semiconductor
film can be formed to have a hydrogen concentration of
1.times.10.sup.19 to 1.times.10.sup.22 atoms/cm.sup.3, preferably,
1.times.10.sup.19 to 5.times.10.sup.20 atoms/cm.sup.3. Using the
contained hydrogen, a termination effect of releasing dangling
bonds within the semiconductor film, can be obtained. Further,
using the hydrogen, flexibility of the thin film integrated circuit
can be increased.
[0123] Further, the percentage of an area of the thin film
integrated circuit occupied by a patterned semiconductor film is
set 1 to 30%, and thus, breakdown or peeling of the thin film
transistor due to bending stress can be prevented.
[0124] In the case of such a TFT having a semiconductor, the
subthreshold coefficient (S value) of the TFT can be set 0.35 V/sec
or lower, preferably, 0.25 to 0.09 V/sec, and the mobility of the
TFT can be set to be 10 cm.sup.2/Vsec or higher.
[0125] When a 19-stage ring oscillator is formed by using the TFT,
a characteristic of the oscillation frequency of 1 MH or more,
preferably 100 MHz or more at the power supply voltage of 3 to 5 V
can be obtained. In addition, the delay time for each stage of an
inverter can be 26 ns, preferably 0.26 ns or less at the power
supply voltage of 3 to 5 V.
[0126] As described above, such a thin film integrated circuit
includes an extremely thin semiconductor film as an active region.
Thus, the thin film integrated circuit can be thinner as compared
with an IC chip formed from a silicon wafer. Specific thickness of
such a thin film integrated circuit is set 0.3 .mu.m to 3 .mu.m,
typically about 2 .mu.m.
[0127] By the above described structure, a function of a TFT can be
obtained; however, preferably, a first interlayer insulating film
127 and a second interlayer insulating film 129 may be formed.
Damages, defects or the like of a semiconductor film from a laser
can be repaired by hydrogen from the first interlayer insulating
film 127. In other words, a termination effect of defects by
hydrogen can be obtained. An insulating film containing oxygen or
nitrogen, such as silicon oxide (SiO.sub.x), silicon nitride
(SiN.sub.x), silicon oxynitride (SiO.sub.xN.sub.y) (x>y) and
silicon nitride oxide (SiN.sub.xO.sub.y) (x>y) (x, y=1, 2 . . .
) can be used for the first interlayer insulating film 127.
[0128] Planarity can be enhanced by the second interlayer
insulating film 129. An organic material or an inorganic material
can be used for the second interlayer insulating film 129.
Polyimide, acrylic, polyamide, polyimide amide, a resist,
benzocyclobutene, siloxane, or polysilazane can be used as the
organic material. Siloxane has a skeleton structure with a bond of
silicon (Si) and oxygen (O). As a substituent thereof, an organic
group including at least hydrogen (such as alkyl group or aromatic
hydrocarbon) is used. Further, a fluoro group may be used for the
substituent. Also, an organic group including at least hydrogen and
a fluoro group may be used for the substituent. Polysilazane is
formed from a liquid material including a polymer material having a
bond of silicon (Si) and nitrogen (N). An insulating film
containing oxygen or nitrogen such as a silicon oxide (SiO.sub.x)
film, a silicon nitride (SiN.sub.x) film, a silicon oxynitride
(SiO.sub.xN.sub.y) (x>y) film, or a silicon nitride oxide
(SiN.sub.xO.sub.y) (x>y) (x, y=1, 2 . . . ) film can be used as
the inorganic material. In addition, a laminated structure of the
insulating films described above may be used for the second
interlayer insulating film 129. When the second interlayer
insulating film 129 is formed by using e.g., an organic material,
planarity is improved; however water and oxygen are easily
absorbed. An insulating film containing an inorganic material is
preferably formed over the organic material to prevent absorption
of water and oxygen. When an insulating film containing nitrogen is
used for the inorganic material, entry of alkali ions such as Na,
in addition to water, can be prevented.
[0129] More preferably, a fourth insulating film 131 is provided to
cover the wiring 130. Since an article mounted with a thin film
integrated circuit is often touched by bare hands, there is concern
of diffusion of alkali ions such as Na. Therefore, the fourth
insulating film 131 is preferably formed on the top surface of the
thin film integrated circuit. An insulating film containing oxygen
or nitrogen such as a silicon oxide (SiOx) film, a silicon nitride
(SiNx) film, a silicon oxynitride (SiOxNy) (x>y) film, or a
silicon nitride oxide (SiN.sub.xO.sub.y) (x>y) (x, y=1, 2 . . .
) film can be used as the fourth insulating film 131. Typically, a
silicon nitride oxide (SiNxOy) film may be used.
[0130] Thereafter, a groove 105 is formed between the thin film
integrated circuits 101. The groove 105 can be formed by dicing,
scribing, etching with the use of a mask, or the like. The shape of
the groove 105 can be circular (hole) or rectangular (slit-like). A
blade dicing method with a dicing apparatus (dicer) is commonly
employed for dicing. The blade is a grinding stone into which
diamond abrasive grains are embedded, and has the width of
approximately 30 .mu.m to 50 .mu.m. The TFT layer 103 is separated
by rapidly spinning the blade. A diamond scribing method, a laser
scribing method, or the like is used for scribing. In the case of
etching, the TFT layer can be separated by dry etching, wet
etching, or the like after forming a mask pattern by a
light-exposure step and a development step. In dry etching, an
atmospheric plasma method may be used. Thus, by employing the above
described method, the groove 105 can be formed between the thin
film integrated circuits 101.
[0131] Note that the groove 105 need not necessarily be formed
between each thin film integrated circuits, but it may be formed
between regions where plural thin film integrated circuits are
formed.
[0132] An opening portion may be formed in the TFT layer 103. In
this case, the opening portion is required to be formed in a region
other than the region where a conductive film to become a channel
formation region is formed. By using such an opening portion and a
groove together, the size or number of the groove 105 can be
adjusted or the time required for removing the separation layer 102
can be shortened. The opening portion may be circular, rectangular
or the like.
[0133] When the groove 105 is selectively formed between each thin
film integrated circuit 101, an insulating film or a conductive
film is left in a region other than the groove 105 between the thin
film integrated circuits. Such an insulating film, a conductive
film or the like that is left between thin film integrated circuits
is referred to as a connection region 106. Note that the connection
region 106 may have a function of connecting the thin film
integrated circuits so as not to be isolated from one another, and
may include any of an insulating film and a conductive film.
Further, the connection region may be formed as a single layer or a
laminated layer.
[0134] The thin film integrated circuit 101 is fixed to the
insulating substrate 100 in a region 104 where the separation layer
102 is not formed. Therefore, the thin film integrated circuit 101
is never separated from the insulating substrate 100.
[0135] At this time, the separation layer 102 is removed. Firstly,
an etching agent for removing the separation layer 102 is
introduced. As the etching gas, a gas or a liquid containing
halogen fluoride can be employed. For example, ClF.sub.3 (chlorine
trifluoride) can be used as halogen fluoride. Note that ClF.sub.3
can be generated through a process of
Cl.sub.2(g)+3F.sub.2(g).fwdarw.2ClF.sub.3(g) by the reaction of
chlorine with fluorine at temperatures of 200.degree. C. or more.
CiF.sub.3 (boiling point: 11.75.degree. C.) can liquefy depending
on the temperature of the reaction field. In such a case, wet
etching can also be employed using ClF.sub.3 as the liquid
containing halide. A gas of ClF.sub.3 or the like mixed with
nitrogen may be used as another gas containing halide.
[0136] The etching agent is not limited to ClF.sub.3 or halide as
long as it etches the separation layer 102 but it does not etch the
base film. For example, a plasma gas containing fluorine such as
CF.sub.4, SF.sub.6, NF.sub.3, or F.sub.2 can be used. A strong
alkaline solution such as tetraethylammonium hydroxide (TMAH) may
be used as another etching agent.
[0137] In the case of chemically removing the separation layer 102
with a gas containing halide such as ClF.sub.3, the combination of
the separation layer 102 and the base film is not limited to the
above-described material, as long as the material that is
selectively etched is used for the separation layer 102 and a
material that is not etched is used for the base film.
[0138] In this embodiment mode, the separation layer 102 can be
removed with a low pressure CVD apparatus under the following
conditions: an etching agent is ClF.sub.3 (chlorine trifluoride)
gas; temperature, 350.degree. C.; flow rate, 300 sccm; pressure,
799.8 Pa (6 Torr); and time, 3 hours. However, the conditions are
not limited thereto. Further, a low pressure CVD apparatus has a
bell jar that can treat plural thin film integrated circuits 100.
As the result thereof, mass-productivity of thin film integrated
circuits can be increased. When an unnecessary gas is expelled
through an exhaust pipe, there is no possibility that the thin film
integrate circuits are drawn into the exhaust pipe since the thin
film integrated circuits are integrated with the insulating
substrate 100 by the connection region 106.
[0139] Further, a heating means, for example, a heater may be
provided on the side face of the low pressure CVD apparatus. The
process temperature is set at 100 to 300.degree. C. by a heating
means, thereby increasing the reaction speed of the separation
layer 102 and an etching agent. Accordingly, the amount of used
etching agent can be reduced and the process time can be
shortened.
[0140] The separation layer 102 gradually recedes by introducing an
etching agent in the above aforementioned manner. Thus, the
separation layer 102 can be removed.
[0141] When introducing an etching agent, an etching agent, gas
flow rate, temperature, and the like are set so that the TFT layer
103 is not etched. Since ClF.sub.3 used in this embodiment mode has
a characteristic of selectively etching silicon, it can selectively
remove the separation layer 102. Therefore, an insulating film
containing oxygen or nitrogen is preferably used as the base
insulating film so that the TFT layer 103 is not etched. Since
difference in the reaction rate between the separation layer and
the base film is large, meaning that the selectivity is high, the
separation layer 102 can be easily removed, with the thin film
integrated circuit protected. In this embodiment mode, it is
possible to prevent the TFT layer 103 from reacting with the
etching agent, by using silicon oxynitride or the like provided
above and below the TFT layer 103 and edge portions of an
interlayer insulating film, a gate insulating film, a wiring, and
the like which are exposed on the side face.
[0142] Thereafter, the insulating substrate 100 is separated. At
this time, the thin film integrated circuits are not separated from
one another, since they are connected by the connection region
106.
[0143] The separated insulating substrate 100 can be reused.
Accordingly, reduction in cost of thin film integrated circuits can
be achieved. In the case of reuse, dicing, scribing, or the like in
forming the groove 105 is preferably conducted in order not to
damage the insulating substrate 100. However, even when the
insulating substrate is damaged, a planarizing treatment can be
performed by forming an organic resin or an inorganic film using a
coating method or a droplet discharge method. Note that a droplet
discharge method is a method for selectively discharging (spraying)
a droplet (also referred to as a dot) of a composition mixed with a
material of a conductive film, an insulating film, or the like,
which is also referred to as an ink-jet method depending on its
system.
[0144] As shown in FIG. 11A, the thin film integrated circuits can
be attached to a different base material 142 by an adhesive agent
141. The base material 142 may be a flexible substrate. A substrate
made of a flexible synthetic resin such as plastic typified by
polyethylene terephthalate (PET), polyethylene naphthalate (PEN),
or polyeter sulfone (PES) or acrylic can be used as the flexible
substrate.
[0145] An adhesive agent of a thermosetting resin, an ultraviolet
curing resin, an epoxy resin, a resin additive, or the like; a
two-sided tape; or the like can be used as the adhesive agent
141.
[0146] As a result of transferring the thin film integrated circuit
to the flexible substrate, the flexibility and the breaking
strength of the thin film integrated circuit can be increased. The
thin film integrated circuit transferred to the flexible substrate
can be made more lightweight, thinner, and more flexible than a
thin film integrated circuit formed over the insulating substrate
100.
[0147] The different base material 142 may be a surface of an
article on which the thin film integrated circuit is to be mounted.
In other words, the thin film integrated circuit 101 without the
insulating substrate 100 can be completed and mounted on an
article. Thus, thinning of a thin film integrated circuit, and
thinning and reducing in weight of an article mounted with the thin
film integrated circuit can also be achieved.
[0148] Thereafter, the thin film integrated circuits are cut by a
dicing, scribing, or laser cutting method. For example, the thin
film integrated circuits can be cut by using a laser which is
absorbed by a glass substrate, such as a CO.sub.2 laser.
[0149] The periphery of the thin film integrated circuit such as a
side face may be covered with an organic resin such as an epoxy
resin. Accordingly, the thin film integrated circuit is protected
from outside and becomes easily portable.
[0150] The thusly sectioned thin film integrated circuit can be 5
mm square (25 mm.sup.2) or less, preferably, 0.3 mm square (0.09
mm.sup.2) to 4 mm square (16 mm.sup.2).
[0151] When a thin film integrated circuit is formed on the
insulating substrate 100, it has fewer limitations on the shape of
a mother substrate as compared with an IC chip formed by using a
circular silicon wafer. Therefore, mass-productivity of thin film
integrated circuits is enhanced and thus thin film integrated
circuits can be mass-produced. Cost reduction of thin film
integrated circuits can be achieved, since the insulating substrate
100 is reused.
[0152] The thin film integrated circuit of the present invention
has a semiconductor film of 0.2 .mu.m or less, typically 40 nm to
170 nm, preferably 50 nm to 150 nm, as an active region and is very
thin, unlike an IC chip formed with a silicon wafer. Accordingly,
even when the thin film integrated circuit is mounted on an
article, the thin film integrated circuit is difficult to be
confirmed, which helps to prevent falsification.
[0153] In order to increase the strength of such a thin film
integrated circuit, the method for transferring to a flexible
substrate can be employed. Such a thin film integrated circuit is
harder to damage than an IC chip formed from a silicon wafer.
[0154] A thin film integrated circuit of the present invention is
in no danger of wave absorption and has good reception of signals
as compared to an IC chip formed from a silicon wafer, since the
thin film integrated circuit does not have a silicon wafer.
[0155] Since the thin film integrated circuit of the present
invention does not have a silicon wafer, it can be
light-transmitting. As a result, the design is not spoiled, even if
the thin film integrated circuit is mounted on a printed surface of
an article.
[0156] A thin film integrated circuit of the present invention can
obtain electric power or a signal by an antenna. This antenna can
be formed directly on the thin film integrated circuit. In
addition, the thin film integrated circuit can be attached to an
antenna that is formed on another substrate.
[0157] Specifically, thin semiconductor devices including thin film
integrated circuits include a contactless thin semiconductor device
mounted with an antenna (functioning as a RF tag or an RF chip), a
contact thin semiconductor device provided with a terminal
connected to an external power source without an antenna mounted,
and a hybrid thin semiconductor device which is a combination of a
contactless one and a contact one. The thin film integrated circuit
shown in this embodiment mode can be applied to any of the thin
semiconductor devices described above.
[0158] The thus formed thin film integrated circuits are each
mounted on a thin semiconductor device. For example, as shown in
FIG. 12A, each thin film integrated circuit 101 is cut out from the
insulating substrate 100. The thin film integrated circuit 101 is
mounted on a thin semiconductor device, specifically, a base
material 200 for a card. For example, cases where a thin film
integrated circuit 101a in which an antenna is integrated and a
thin film integrated circuit 101b in which an antenna is not
integrated are each mounted on the base material 200 are described.
An external antenna 201 is formed on the base material 200, and a
thin film integrated circuit 101b is mounted to be electrically
connected to the antenna. At the time, the antenna can be connected
to the thin film integrated circuit 101b by a resin having a
conductor, e.g., anisotropic conductive resin (ACF). In addition,
the thin film integrated circuit 101a where an antenna is
integrated is mounted on the base material 200 by an adhesive
agent, e.g., a two-sided tape (FIG. 12B).
[0159] After that, as shown in FIG. 12C, a sheet for regulating
thickness regulation, and a sheet (overlay sheet) for the front and
back sides are formed, thereby completing a thin semiconductor
device, specifically a card 203. Characters and pictures can be
printed on the sheet for the front and back sides. In addition, by
mounting a thin film integrated circuit, it is unnecessary to print
a card number or the like that has been printed on a conventional
card. Further, security can be enhanced since a plurality of thin
film integrated circuits can be mounted.
[0160] Since a thin film integrated circuit of the present
invention is formed on an insulating substrate 100, it has fewer
limitations on the shape of a mother substrate as compared with an
IC chip formed by using a circular silicon wafer. Therefore,
mass-productivity of thin film integrated circuits is enhanced and
thus thin film integrated circuits can be mass-produced. As the
result thereof, cost reduction of thin film integrated circuits can
be expected. A thin film integrated circuit formed at extremely low
unit cost can generate big profits.
[0161] For example, the case of using a silicon substrate with a
diameter of 12 inches is compared with the case of using a glass
substrate with a size of 730.times.920 mm.sup.2. The silicon
substrate has an area of about 73000 mm whereas the glass substrate
has an area of about 672000 mm.sup.2, that is, the glass substrate
is about 9.2 times larger than the silicon substrate. On the glass
substrate with an area of about 672000 mm.sup.2, about 672000 ID
chips each having an area of 1 mm square can be formed when a
margin for cutting the substrate is not taken into account, which
is about 9.2 times more than the ID chips formed on the silicon
substrate. In the case of using the glass substrate with a size of
730.times.920 mm.sup.2, which requires fewer manufacturing steps,
facility investment cost for mass production of ID chips can be
reduced by one-third of the case in which the silicon substrate
with a diameter of 12 inches is used.
Embodiment Mode 6
[0162] Embodiment Mode 6 describes a mode of a plurality of thin
film integrated circuits included in a thin semiconductor
device.
[0163] In FIG. 13, a plurality of thin film integrated circuits
101a, 101b, 101c and 101d in which memories 10a, 10b, 10c and 10d
and antennas 11a, 11b, 11c and 11d are respectively integrated and
are mounted on a base material 200. In this manner, the plurality
of thin film integrated circuits having the same shape can have
different communication protocols, different storage information to
a memory, or the like. Consequently, this case can enhance security
of a thin semiconductor device more, as compared with the case of
mounting the same thin film integrated circuits.
[0164] As shown in FIG. 14, a memory 10 formed over the base
material 200 may be shared by the thin film integrated circuits
101a, 101b, 101c, 101d, and 101e. By sharing the memory that
occupies the largest area, miniaturization of a thin semiconductor
device can be achieved. Further, a mounting area of a thin film
integrated circuit is enlarged and thus, the possibility of
mounting increases. In addition, the thin film integrated circuits
each have the antennas 11a, 11b, 11c, 11d and 11e; however, the
shape of each antenna is not limited to those in FIG. 14.
[0165] As shown in FIG. 15, thin film integrated circuits 101a,
101b, and 101c having different antenna lengths based on each
antenna 11a, 11b and 11c formed over the base material 200, may be
mounted.
[0166] A thin semiconductor device of the present invention is not
limited to the modes of the thin film integrated circuits shown in
FIGS. 13 to 15. The thin film integrated circuits shown in FIGS. 13
to 15 can be combined with one another.
[0167] In this embodiment mode, a contactless thin semiconductor
device having a thin film integrated circuit mounting an antenna is
described; however, a mode of a thin semiconductor device is not
limited thereto. In other words, a contact thin semiconductor
device having a connection terminal, or a hybrid thin semiconductor
device which is a combination of a contactless one and a contact
one may be employed.
[0168] This embodiment mode describes the case where each thin film
integrated circuit has an antenna; however, an antenna can be
shared by a plurality of thin film integrated circuits.
Embodiment Mode 7
[0169] Embodiment Mode 7 describes an article mounted with an ID
chip (hereinafter, a chip group) on which a plurality of thin film
integrated circuits are mounted.
[0170] As an example of prevention of counterfeiting products,
cases of mounting a chip group on various products are described.
Cases in which a chip group is attached to a passport, a license
card, or the like are described in this embodiment mode.
[0171] FIG. 16A illustrates a passport 311 mounted with a chip
group 30. The chip group 30 includes four thin film integrated
circuits 320 in which each memory 321 is integrated. In FIG. 16A,
the chip group 30 is mounted on a front cover of the passport;
however, it may be mounted on another page and may be mounted on a
surface of the cover since the chip group 30 is light-transmitting.
Alternatively, the chip group 30 may be embedded in the cover so as
to be sandwiched by a material of the cover or the like. By
mounting a chip group of the present invention, its security such
as prevention of falsification of a thin film integrated circuit or
information leakage from a thin film integrated circuit can be
enhanced. Counterfeiting a passport or the like can be
prevented.
[0172] Note that, in FIG. 16A, the chip group 30 having memories
321 integrated in the four thin film integrated circuits 320 is
described; however the present invention is not limited thereto. In
other words, in the present invention, the number of thin film
integrated circuits, memories, and methods for forming a thin film
integrated circuit and a memory are not limited.
[0173] FIG. 16B illustrates a license card 312 mounted with the
chip group 30. The chip group 30 includes four thin film integrated
circuits 320 in which a memory 321 is integrated. In FIG. 16B, the
chip group 30 is embedded in the license card 312. The chip group
30 which is light-transmitting may be set on a print side of the
license card 312, for example, the chip group 30 can be set on the
print side of the license card 312 and covered with a laminate
material. Alternatively, the chip group 30 may be embedded in the
license card 312 so as to be sandwiched by a material of the
license card 312. By mounting a chip group of the present
invention, its security such as prevention of falsification of a
thin film integrated circuit or information leakage from a thin
film integrated circuit can be enhanced. Counterfeiting a license
card or the like can be prevented.
[0174] By setting a chip group to these articles, counterfeiting
can be prevented. The chip group that is very thin and compact can
be used and therefore, the design of a passport, a license card and
the like is not spoiled. Moreover, the chip group is
light-transmitting, thus it may be set on a surface of an
article.
[0175] In addition, according to the chip group, management of
passports, license cards and the like can be simplified. Moreover,
data can be stored in a chip group without writing directly in
passports, license cards and the like; therefore our privacy can be
protected.
[0176] A chip group of the present invention may be mounted on an
expensive bag, e.g., a designer bag. Consequently, distribution of
such forged articles (fakes) can be prevented.
[0177] Note that, in FIG. 16B, the chip group 30 having the four
thin film integrated circuits 320 sharing one memory 321 is
described; however the present invention is not limited thereto. In
other words, in the present invention, the number of thin film
integrated circuits, memories, and methods for forming a thin film
integrated circuit and a memory are not limited.
[0178] In FIGS. 16A and 16B, an antenna is not shown; however an
antenna shared by plural thin film integrated circuits can be
provided or an antenna can be integrated in each thin film
integrated circuit. When frequencies received by thin film
integrated circuits are different, an antenna is preferably
provided for each thin film integrated circuit, since it is
preferable that antenna lengths are changed according to the
frequencies. At this time, a thin film integrated circuit having a
long antenna length may be connected to an antenna formed outside
the thin film integrated circuit (an external antenna).
[0179] Because a chip group is very thin and small, and can be more
flexible, the chip group can be mounted on a sheet-like article. As
an example of sheet-like articles, the case of mounting a chip
group on a bill is described.
[0180] As shown in FIG. 17, a chip group 30 is mounted on a bill
313. The chip group 30 includes two thin film integrated circuits
in which a memory 321 and an antenna 322 are integrated, and one
thin film integrated circuit 320 which is connected to an external
antenna 322 and in which a memory 321 is integrated. Although the
chip group is mounted inside the bill in FIG. 17, it may be exposed
on a surface thereof.
[0181] The bill may be printed using an ink containing plural chip
groups. Further, chip groups may be scattered to form a bill when
mixing a material of the bill and chemicals. Since such a chip
group, that is, thin film integrated circuits can be formed at a
low cost, a plurality of chip groups can be mounted on a bill
without adversely affecting the production cost of the bill.
[0182] A chip group may be mounted on portfolios such as stock
certificates or checks, or coins as well as on bills.
[0183] By mounting plural thin film integrated circuits of the
present invention, its security such as prevention of falsification
of a thin film integrated circuit or information leakage from a
thin film integrated circuit can be enhanced. Counterfeiting
portfolios or the like can be prevented.
[0184] Such a sheet article is frequently bent, therefore, a
bending stress applied to a chip group must be taken into
consideration. As an example, a state where a bill mounted with a
chip group, is bent, is described. Generally, a sheet article
easily bends or is easily bent in a longitudinal direction,
therefore, the case of bending in a longitudinal direction is
described. The a thin film transistor of a thin film integrated
circuit of the chip group 30 includes a source region, a channel
formation region, and a drain region. When bending an article, it
is preferable that the thin film transistor of a thin film
integrated circuit of the chip group 30 be disposed so that the
bending direction is perpendicular to the direction that carriers
move. That is, the source region, the channel formation region, and
the drain region are disposed so as to be perpendicular to the
bending direction. As a result, the thin film transistor being
broken and peeled off by the bending stress can be prevented.
[0185] As shown in FIG. 19, in the case of using a crystalline
semiconductor film using laser irradiation, the laser scanning
direction (X-axis direction) is preferably set perpendicular to the
bending direction as well.
[0186] By bending a chip group in the bending direction, a thin
film integrated circuit of the chip group, in particular, a thin
film transistor is not broken and grain boundaries that exist in
the direction that carriers move can considerably be decreased. As
a result, electronic characteristics, in particular, mobility of
the thin film transistor can be improved.
[0187] In addition, when a patterned semiconductor film occupies 1
to 30% of an area of the chip group, the thin film transistor being
broken and peeled off by the bending stress can be prevented.
[0188] Since a material having extensibility can be used for an
antenna, a bending direction of the antenna does not necessarily
need to be considered, unlike a chip group.
[0189] FIG. 17 shows the chip group 30 including two thin film
integrated circuits in which memories 321 and antennas 322 are
integrated, and one thin film integrated circuit 320 which is
connected to an external antenna 322 and in which a memory 321 is
integrated. In other words, the number of thin film integrated
circuits, memories, and methods for forming a thin film integrated
circuit and a memory are not limited.
[0190] Described hereinafter is a mode of using an IC card using a
contact chip group as electronic money. FIG. 18 shows a mode that a
credit card 351 is used to make a payment. The credit card 351
includes a chip group 30. The chip group 30 includes two thin film
integrated circuits in which memories 321 and antennas 322 are
integrated, and one thin film integrated circuit 320 which is
connected to an external antenna 322 and a memory 321 is
integrated. A cash register 352 and a reader/writer 353 needed for
payment are provided. The chip group 30 stores information on the
amount deposited into the credit card 351. The information on the
deposited amount can be read and transferred to the cash register
352 without contact by the reader/writer 353. The cash register 352
verifies that the amount on the credit card 351 is more than the
amount to be paid for, and thus payment is made. Then, the
information of the remaining amount of the money after the payment
is transmitted to the reader/writer 353 and can be written in the
chip group 30 by the reader/writer 353. In this manner, when the
chip group is accessed by the reader/writer, key information is
received by plural integrated circuits, thereby enhancing
security.
[0191] Note that the reader/writer 353 may be equipped, so as to
enhance the security, with a key pad 354 for inputting a personal
identification number and the like, thereby preventing the credit
card 351 from being used to make payment by a third person without
permission.
[0192] By mounting plural thin film integrated circuits of the
present invention on a credit card or the like, its security such
as prevention of falsification of a thin film integrated circuit or
information leakage from a thin film integrated circuit can be
enhanced. Counterfeiting a credit card or the like can be
prevented.
* * * * *