U.S. patent application number 12/268558 was filed with the patent office on 2009-03-19 for semiconductor device and method for manufacturing the same, and electric device.
This patent application is currently assigned to SEMICONDUCTOR ENERGY LABORATORY CO., LTD.. Invention is credited to Hideaki KUWABARA, Hiroko YAMAMOTO.
Application Number | 20090073325 12/268558 |
Document ID | / |
Family ID | 36695934 |
Filed Date | 2009-03-19 |
United States Patent
Application |
20090073325 |
Kind Code |
A1 |
KUWABARA; Hideaki ; et
al. |
March 19, 2009 |
SEMICONDUCTOR DEVICE AND METHOD FOR MANUFACTURING THE SAME, AND
ELECTRIC DEVICE
Abstract
It is an object of the present invention to simplify steps
needed to process a wiring in forming a multilayer wiring. In
addition, when a droplet discharging technique or a nanoimprint
technique is used to form a wiring in a contact hole having a
comparatively long diameter, the wiring in accordance with the
shape of the contact hole is formed, and the wiring portion of the
contact hole is likely to have a depression compared with other
portions. A penetrating opening is formed by irradiating a
light-transmitting insulating film with laser light having high
intensity and a pulse high in repetition frequency. A plurality of
openings having a minute contact area is provided instead of
forming one penetrating opening having a large contact area to have
an even thickness of a wiring by reducing a partial depression and
also to ensure contact resistance.
Inventors: |
KUWABARA; Hideaki; (Isehara,
JP) ; YAMAMOTO; Hiroko; (Hadano, JP) |
Correspondence
Address: |
NIXON PEABODY, LLP
401 9TH STREET, NW, SUITE 900
WASHINGTON
DC
20004-2128
US
|
Assignee: |
SEMICONDUCTOR ENERGY LABORATORY
CO., LTD.
Atsugi-shi
JP
|
Family ID: |
36695934 |
Appl. No.: |
12/268558 |
Filed: |
November 11, 2008 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
11329095 |
Jan 11, 2006 |
|
|
|
12268558 |
|
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Current U.S.
Class: |
348/790 ; 257/59;
257/E27.06; 348/739; 348/800; 348/E5.133 |
Current CPC
Class: |
H01L 21/76816 20130101;
H01L 23/49855 20130101; H01L 27/1292 20130101; H01L 2924/00
20130101; H01L 21/76838 20130101; H01L 27/1285 20130101; H01L
27/124 20130101; H01L 21/76802 20130101; H01L 23/5226 20130101;
H01L 21/76877 20130101; H01L 2924/0002 20130101; H01L 2924/12044
20130101; H01L 29/41733 20130101; G02F 1/136227 20130101; H01L
21/288 20130101; H01L 2924/0002 20130101 |
Class at
Publication: |
348/790 ; 257/59;
348/739; 348/800; 257/E27.06; 348/E05.133 |
International
Class: |
G09G 3/30 20060101
G09G003/30; H01L 27/088 20060101 H01L027/088; G09G 3/36 20060101
G09G003/36 |
Foreign Application Data
Date |
Code |
Application Number |
Jan 21, 2005 |
JP |
2005-014756 |
Claims
1. A active matrix display device comprising: a thin film
transistor formed over a substrate, the thin film transistor
comprising a semiconductor layer wherein the semiconductor layer
comprises a metal oxide including at least indium; and a pixel
electrode formed over the substrate and electrically connected to
the thin film transistor.
2. The active matrix display device according to claim 1, wherein
the metal oxide includes zinc, gallium, and indium.
3. The active matrix display device according to claim 1, wherein
the thin film transistor is a bottom gate thin film transistor.
4. The active matrix display device according to claim 1, wherein
the thin film transistor is a top gate thin film transistor.
5. The active matrix display device according to claim 1, wherein
the active matrix display device is a liquid crystal display
device.
6. The active matrix display device according to claim 1, wherein
the active matrix display device is an EL display device.
7. The active matrix display device according to claim 1, wherein
the substrate is a plastic substrate.
8. The active matrix display device according to claim 1, further
comprising an interlayer insulating film formed over the thin film
transistor wherein the pixel electrode is electrically connected to
the thin film transistor though a plurality of openings formed in
the interlayer insulating film.
9. An active matrix display device comprising: a thin film
transistor formed over a substrate; and a pixel electrode formed
over the substrate and electrically connected to the thin film
transistor, the thin film transistor including: at least two gate
electrodes electrically connected to each other; a gate insulating
film formed over at least the two gate electrodes; and a
semiconductor layer formed over the gate insulating film so as to
overlap the two gate electrodes wherein the semiconductor layer
comprises a metal oxide including at least indium.
10. The active matrix display device according to claim 9, wherein
the metal oxide includes zinc, gallium, and indium.
11. The active matrix display device according to claim 9, further
comprising a wiring over the semiconductor layer wherein the pixel
electrode is connected to the wiring.
12. The active matrix display device according to claim 9, wherein
the thin film transistor is a top gate thin film transistor.
13. The active matrix display device according to claim 9, wherein
the active matrix display device is a liquid crystal display
device.
14. The active matrix display device according to claim 9, wherein
the active matrix display device is an EL display device.
15. The active matrix display device according to claim 9, wherein
the substrate is a plastic substrate.
16. The active matrix display device according to claim 9, further
comprising an interlayer insulating film formed over the thin film
transistor wherein the pixel electrode is electrically connected to
the thin film transistor through a plurality of openings formed in
the interlayer insulating film.
17. A television device comprising: a tuner for receiving a video
signal; a video signal processing circuit operationally connected
to the tuner; and an active matrix display device operationally
connected to the video signal processing circuit, the active matrix
display device comprising: a thin film transistor formed over a
substrate, the thin film transistor comprising a semiconductor
layer wherein the semiconductor layer comprises a metal oxide
including at least indium; and a pixel electrode formed over the
substrate and electrically connected to the thin film
transistor.
18. The television device according to claim 17, wherein the metal
oxide includes zinc, gallium, and indium.
19. The television device according to claim 17, wherein the thin
film transistor is a bottom gate thin film transistor.
20. The television device according to claim 17, wherein the thin
film transistor is a top gate thin film transistor.
21. The television device according to claim 17, wherein the active
matrix display device is a liquid crystal display device.
22. The television device according to claim 17, wherein the active
matrix display device is an EL display device.
23. The television device according to claim 17, wherein the
substrate is a plastic substrate.
24. The television device according to claim 17, further comprising
an interlayer insulating film formed over the thin film transistor
wherein the pixel electrode is electrically connected to the thin
film transistor though a plurality of openings formed in the
interlayer insulating film.
25. A television device comprising: a tuner for receiving a video
signal; a video signal processing circuit operationally connected
to the tuner; and an active matrix display device operationally
connected to the video signal processing circuit, the active matrix
display device comprising: a thin film transistor formed over a
substrate, and a pixel electrode formed over the substrate and
electrically connected to the thin film transistor, the thin film
transistor including: at least two gate electrodes electrically
connected to each other; a gate insulating film formed over at
least the two gate electrodes; and a semiconductor layer formed
over the gate insulating film so as to overlap the two gate
electrodes wherein the semiconductor layer comprises a metal oxide
including at least indium.
26. The television device according to claim 25, wherein the metal
oxide includes zinc, gallium, and indium.
27. The television device according to claim 25, further comprising
a wiring over the semiconductor layer wherein the pixel electrode
is connected to the wiring.
28. The television device according to claim 25, wherein the thin
film transistor is a top gate thin film transistor.
29. The television device according to claim 25, wherein the active
matrix display device is a liquid crystal display device.
30. The television device according to claim 25, wherein the active
matrix display device is an EL display device.
31. The television device according to claim 25, wherein the
substrate is a plastic substrate.
32. The television device according to claim 25, further comprising
an interlayer insulating film formed over the thin film transistor
wherein the pixel electrode is electrically connected to the thin
film transistor through a plurality of openings formed in the
interlayer insulating film.
33. A active matrix display device comprising: a bottom gate type
thin film transistor formed over a substrate, the bottom gate type
thin film transistor comprising a semiconductor layer wherein the
semiconductor layer comprises a metal oxide including zinc,
gallium, and indium; and a pixel electrode formed over the
substrate and electrically connected to the thin film
transistor.
34. The active matrix display device according to claim 33, wherein
the active matrix display device is a liquid crystal display
device.
35. The active matrix display device according to claim 33, wherein
the active matrix display device is an EL display device.
36. The active matrix display device according to claim 33, wherein
the substrate is a plastic substrate.
37. A active matrix display device comprising: a thin film
transistor formed over a substrate, the thin film transistor
comprising a semiconductor layer wherein the semiconductor layer
comprises a metal oxide including at least indium; a pixel
electrode formed over the substrate and electrically connected to
the thin film transistor; and a driver circuit comprising an IC
chip operationally connected to the thin film transistor.
38. The active matrix display device according to claim 37, wherein
the metal oxide includes zinc, gallium, and indium.
39. The active matrix display device according to claim 37, wherein
the active matrix display device is a liquid crystal display
device.
40. The active matrix display device according to claim 37, wherein
the active matrix display device is an EL display device.
41. The active matrix display device according to claim 37, wherein
the substrate is a plastic substrate.
42. The active matrix display device according to claim 37, wherein
the IC chip is mounted on the substrate.
43. The active matrix display device according to claim 37, wherein
the driver circuit is a scanning-line driver circuit.
44. The active matrix display device according to claim 37, wherein
the driver circuit is a signal-line driver circuit.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a semiconductor device
having a circuit including a thin film transistor (hereinafter,
referred to as a TFT) and to a manufacturing method thereof.
Specifically, the present invention relates to a semiconductor
device having a circuit including a field effect transistor
(hereinafter, referred to as an FET). For example, the present
invention relates to an electronic device incorporating, as part
thereof, a large-scale integrated circuit (LSI), an electro-optic
device typified by a liquid crystal display panel, a light-emitting
display device having an organic light-emitting element, a sensor
device such as a line sensor, or a memory device such as an SRAM or
a DRAM, for example.
[0003] 2. Description of the Related Art
[0004] Note that a semiconductor device in this specification means
general devices and apparatuses that can function with the use of
semiconductor characteristics; for example, an electro-optical
device, a semiconductor circuit, and an electronic device are all
included in a semiconductor device.
[0005] In recent years, in the case of forming a multilayer wiring
in a semiconductor element, irregularities are more significant in
upper layers, and the wirings are difficult to be processed.
Correspondingly, a wiring material is generally embedded in a
wiring opening such as a wiring trench or a hole formed in an
insulating film by a wiring formation technology called a damascene
process.
[0006] A damascene process is a method in which a trench is first
formed in an insulating film, the entire surface is covered with a
metal material (filling the trench), and the entire surface is
polished by a CMP (chemical mechanical polishing) method or the
like to form a metal wiring. The method further including a step of
providing a hole below a metal wiring for contact with a metal
wiring or a semiconductor region in a lower wiring is called a dual
damascene process. The dual damascene process includes a step in
which, after forming a hole for a connection with a lower layer
wiring and a wiring trench are formed, a wiring material is
deposited, and the wiring material except the wiring portion is
removed by a CMP method.
[0007] For a metal wiring using a dual damascene process, copper
(Cu) by an electroplating method is commonly used. In the
electroplating method, a plating solution or the electric field to
be applied is required to be controlled intricately so that copper
(Cu) is completely embedded in the connection hole. In addition, it
is difficult to process copper (Cu) by an etching process using an
etchant or an etching gas; therefore, a special CMP method is
required for polishing for copper (Cu) processing.
[0008] An electroplating method and a CMP method have had a problem
of increase in manufacturing costs for forming a wiring.
[0009] In addition, not only in a manufacturing process of a
semiconductor device using a semiconductor substrate but also in a
manufacturing process of an active matrix substrate using a thin
film transistor (TFT), it is difficult to process a wiring in
forming a multilayer wiring. In recent years, a thin film
transistor is widely applied to an electronic device such as an IC
or an electro-optic device, and is particularly developed as
switching elements for image display devices at a rapid rate. Note
that a liquid crystal display device is generally well known as an
image display device.
[0010] An active matrix liquid crystal display device has often
been used because a high precision image can be obtained compared
with a passive liquid crystal display device. In the active matrix
liquid crystal display device, pixel electrodes arranged in matrix
are driven to display an image pattern on the screen. Specifically,
a voltage is applied to a selected pixel electrode and an opposite
electrode corresponding to the pixel electrode, and thus, a liquid
crystal layer between the pixel electrode and the opposite
electrode is modulated optically. The optical modulation can be
recognized as an image pattern by an observer.
[0011] Application range of such an active matrix liquid crystal
display device is expanding, and demands for the improvement of
productivity and cost reduction are increasing, as a display size
gets larger.
[0012] Conventionally, in the case of forming a multilayer wiring,
in order to connect the upper wiring and the lower wiring, a
contact hole is formed in an interlayer insulating film between
these wirings by using a photolithography method. In the case of
forming a contact hole by using a photolithography method, various
steps such as forming a resist mask (coating, exposing, and
developing a resist), etching selectively, or removing a resist
mask are necessary. In other words, it is necessary to form a
contact hole to have a multilayer structure so that the plurality
of wirings cross to each other, which has been one of causes of
increase in the number of manufacturing processes.
[0013] In addition, in the case of using a photolithography method,
a photomask is also necessary for each exposure pattern; therefore,
a cost for manufacturing the photomask is increased, which has been
one of causes of increase in a manufacturing cost.
[0014] Moreover, in the case of using a photolithography method,
large quantities of resist materials and developing solutions are
used in order to improve uniformity; thus, a great deal of surplus
materials is consumed.
[0015] As for a method for etching an interlayer insulating film
selectively, dry etching and wet etching are known. Generally, dry
etching by gas plasma has an advantage in forming a pattern
processed into a tapered shape or the like. However, a dry-etching
apparatus is disadvantageous in that an expensive large-scaled
apparatus is needed and a manufacturing cost is increased. In
addition, there is a fear that a semiconductor element is damaged
due to gas plasma. Therefore, it is desirable that dry etching is
performed as less as possible.
[0016] In addition, wet etching which is inexpensive and superior
in terms of mass production compared with dry etching uses a great
deal of etchant once; therefore, waste fluid treatment is
difficult, which has been one of causes of increase in a
manufacturing cost. In addition, since wet etching is isotropic
etching, it is difficult to form a contact hole having
comparatively small diameter, which is disadvantageous in high
integration of a circuit.
[0017] As for a method without using a photoresist in processing a
thin film by patterning, a laser-processing technique, particularly
a laser-processing method using YAG laser light (wavelength of 1.06
.mu.m) is known. In the laser-processing method with the use of YAG
laser light, as well as an object to be processed is irradiated
with a spot-like beam, the beam is scanned into a processing
direction to form an opening into a chain shape of continuous
dots.
[0018] In addition, the present applicant uses laser light having a
wavelength of 400 .mu.m or less to irradiate a light-transmitting
conductive film with a linear beam. A method for processing a thin
film for forming an opening is described in Reference 1: U.S. Pat.
No. 4,861,964 Specification, Reference 2: U.S. Pat. No. 5,708,252
Specification, and Reference 3: U.S. Pat. No. 6,149,988
Specification.
SUMMARY OF THE INVENTION
[0019] It is an object of the present invention to simplify steps
needed to process a wiring in forming a multilayer wiring. Further,
it is an object of the present invention to provide a technique to
realize high integration of a circuit.
[0020] In addition, in the case of forming a plurality of contact
holes different in depth, a process tends to be complicated.
Consequently, the present invention provides a technique capable of
realizing a plurality of contact holes different in depth in a
simplified process.
[0021] Moreover, in manufacturing an electronic device having a
semiconductor circuit, a gang printing that is a manufacturing
method of cutting out a plurality of devices from one mother glass
substrate for mass production efficiently is employed without using
a wafer substrate. The size of a mother glass substrate is
increased from 300 mm.times.400 mm of the first generation in the
early 1990s to 680 mm.times.880 mm or 730 mm.times.920 mm of the
fourth generation in 2000. Further, the manufacturing technique has
been developed so that a large number of devices, typically,
display panels can be obtained from one substrate.
[0022] In forming a metal film to be a wiring by a deposition
method with the use of a sputtering method when the substrate size
is further increased hereafter, a target becomes expensive as the
size is increased, which is disadvantageous for mass
production.
[0023] In addition, in consideration of mass production, it is also
an object of the present invention to provide a technique to form a
wiring appropriate for a large-sized substrate.
[0024] According to the present invention, a light-transmitting
insulating film that is formed to cover a conductive layer is
selectively irradiated with laser light to form a penetrating
opening that reaches the conductive layer. A step of forming a
contact hole can be simplified by forming a penetrating opening in
a light-transmitting insulating film by laser light.
[0025] In addition, a focal position of laser light is
appropriately determined by a practitioner. Therefore, the depth of
a penetrating opening or the size of a penetrating opening can be
decided appropriately. Thus, according to the present invention, a
plurality of contact holes different in depth can be realized in a
simplified process. Moreover, the light-transmitting insulating
film is not limited to a single layer, and a step of forming a
contact hole can be simplified even in a stacked layer of two or
more layers.
[0026] According to laser light of the present invention, a
fundamental wave is used without putting laser light into a
non-linear optical element, and a penetrating opening is formed by
irradiating a light-transmitting insulating film with pulsed laser
light having high intensity and a high repetition rate. One feature
of the present invention is that the repetition rate of laser used
in the present invention is set to be 10 MHz or more.
[0027] High intensity means a high peak output power per unit of
time and per area and the peak output power of laser light
according to the present invention ranges from 1 GW/cm.sup.2 to 1
TW/cm.sup.2.
[0028] A fundamental wave with a wavelength of approximately 1
.mu.m is not absorbed so much by a light-transmitting insulating
film in irradiating the light-transmitting insulating film with the
fundamental wave. Thus, the fundamental wave has low absorption
efficiency. A fundamental wave emitted from a pulsed laser having a
pulse width in the range of picosecond or in the range of
femtosecond (10.sup.-15 seconds) can provide high intensity laser
light. Thus, a non-linear optical effect (multi-photon absorption)
is generated and the fundamental wave can be absorbed by
light-transmitting insulating film to form a penetrating
opening.
[0029] Additionally, a shape of an opening in a plane perpendicular
to a substrate can be determined appropriately by a practitioner
appropriately determining a focal position of laser light. For
example, an opening the opening area on a surface of a
light-transmitting insulating film of which is smaller than an
exposed area of a conductive layer can be formed.
[0030] In a conventional processing method using YAG laser light, a
beam shape is circular and light intensity shows a Gaussian
distribution; therefore, an opening shape in a plane perpendicular
to a surface of an object to be processed has a shape in accordance
with a Gaussian distribution. Thus, in the conventional processing
method using YAG laser light, an opening on a surface is likely to
increase in size, and it is difficult to form a deep contact hole
having a minute opening size. In addition, a pulse width that is
used in the conventional processing method using YAG laser light is
10.sup.-4 second to 10.sup.-2 second.
[0031] In addition, in a conventional processing method, where a
light-transmitting conductive film is irradiated with a linear beam
to form an opening with the use of laser light having a wavelength
of 400 .mu.m or less, an opening is formed from the surface of the
light-transmitting conductive film because the light-transmitting
conductive film that absorbs laser light having a wavelength of 400
.mu.m or less is used. A surface easily absorbs energy also in this
processing method; thus, an opening diameter on the surface gets
longer easily.
[0032] Compared with the conventional processing method, a
processing method according to the present invention is not limited
to forming an opening penetrating from a surface, and various
formation methods are available. For example, when a
light-transmitting insulating film is irradiated with laser light
while moving a focal position of the laser light from a conductive
layer side to a surface, an opening penetrating from the conductive
layer side to a surface is formed in the light-transmitting
insulating film. In addition, it is also possible to form an
opening in an insulating film by being irradiated with laser light
to penetrate through a light-transmitting substrate from a
backside, that is, the substrate side.
[0033] In addition, according to the present invention, an opening
having a complicated shape can also be formed by freely moving a
focal position of laser light. For example, an opening penetrating
in a vertical direction is formed in a Z direction (depth
direction) and then a hole in a lateral direction is formed in an X
direction or a Y direction.
[0034] Further, it is also one feature of the present invention to
use a printing technique such as a droplet discharging technique
typified by a piezo type and a thermal jet type or a nanoimprint
technique to form a wiring or an electrode in a position overlapped
with an opening of an insulating film and to electrically connect
to a conductive layer through the opening of the insulating
film.
[0035] For example, in the case of using a droplet discharging
technique, a conductive material where a material solution is
adjusted and dropped can have fluidity; therefore, even an opening
having a crooked complicated shape can be filled with the
conductive material. For example, even a hole where the side wall
is in a reverse tapered shape can be filled with the conductive
material. In addition, a deep opening or an opening having a
complicated shape can be filled with the conductive material by
making the most of speed of a conductive material that is dropped
using a droplet discharging technique. Moreover, it is also one
feature of the present invention to provide an opening filled with
the conductive material having fluidity is easily filled.
[0036] In addition, in the case of using a printing technique such
as a nanoimprint technique, it is also possible to fill an opening
having a complicated shape by giving fluidity to the conductive
material with a conductive material in performing heat treatment
for baking.
[0037] Moreover, when a wiring is formed with the use of a droplet
discharging technique or a nanoimprint technique in a contact hole
having a comparatively long diameter, for example, a diameter
longer than 2 .mu.m, the wiring in accordance with the shape of the
contact hole is formed, and the wiring portion of the contact hole
is likely to have a depression compared with other portions. FIGS.
19A to 19C each shows a state in which a conventional contact hole
is formed. A base insulating film 3011 is provided over a substrate
3010, and a conductive layer 3012 is provided over the base
insulating film 3011. In FIG. 19A, an insulating film is formed
over the conductive layer 3012, a resist mask 3014 is formed by a
photolithography technique, and an opening 3016 is formed by
etching. Then, by removing the resist mask 3014 and forming a
wiring with the use of a droplet discharging technique or a
nanoimprint technique, a wiring 3017a as shown in FIG. 19B is
formed. As shown in FIG. 19B, the wiring 3017a is a wiring in
accordance with the shape of the contact hole and the wiring
portion of the contact hole has a depression compared with other
portions. Further, when baking is performed, the wiring 3017a is
transformed into a wiring 3017b as shown in FIG. 19C because the
wiring material has fluidity. Thus, the wiring material moves to a
material movement direction 3018 shown in an arrow in FIG. 19C and
there is a fear that the thickness of the wiring in vicinity of the
contact hole becomes thinner compared with other portions. In
addition, in the case of using a material having low viscosity and
fluidity in a droplet discharging technique, the material of a
wiring tends to move to a lower place before baking, that is, just
after forming the wiring.
[0038] Thus, it is also one feature of the present invention to
provide a plurality of openings having a minute contact area the
diameter of which is 2 .mu.m or less, preferably approximately 3 nm
to 200 nm, instead of forming one penetrating opening having a
large contact area to have an even thickness of a wiring by
reducing a partial depression and also to ensure contact
resistance.
[0039] According to one feature of the present invention disclosed
in this specification, the example of which is shown in FIG. 1C, a
semiconductor device comprises a first conductive layer; a
plurality of penetrating openings (also referred to as a plurality
of openings); an insulating film covering the first conductive
layer; and a second conductive layer in contact with the first
conductive layer through the plurality of penetrating openings,
wherein the second conductive layer contains conductive particles,
and wherein a surface of the second conductive layer which is
overlapped with the plurality of penetrating openings and a surface
of the second conductive layer which is not overlapped with the
plurality of penetrating openings are formed in one side. In other
words, the second conductive layer is leveled. The width of the
second conductive layer D and a diameter of each of the plurality
of openings W satisfy 2D<W.
[0040] In addition, according to the above feature, the second
conductive layer has a plurality of crystals where the conductive
particles are assembled and the crystals are overlapped. When a
wiring is formed with a conductive material containing metal
particles of 3 nm to 7 nm in size by a droplet discharging method
or a printing method and is baked, the metal particles are
dissolved and assembled to have an approximately 100 nm crystal,
which is formed to irregularly overlap in three dimensions.
[0041] According to another feature of the present invention, a
diameter of a penetrating opening is longer than one conductive
particle. The opening has a diameter longer than a diameter of the
metal particles to be used (3 nm to 7 nm) so that at least the
metal particles enter the opening on the surface. Specifically, a
diameter of a penetrating opening according to the present
invention is 3 nm to 2000 nm.
[0042] In addition, the present invention is not limited to the
opening in contact with the lower conductive layer. According to
another feature of the present invention, a semiconductor device
comprises a semiconductor layer, a plurality of penetrating
openings; an insulating film covering the semiconductor layer; and
a conductive layer in contact with the semiconductor layer through
the plurality of penetrating openings, wherein the conductive layer
contains conductive particles, and wherein a surface of the
conductive layer which is overlapped with the plurality of
penetrating openings and a surface of the conductive layer which is
not overlapped with the plurality of penetrating openings are
formed in one side.
[0043] In addition, according to the present invention, a shape of
the penetrating opening is not limited to a columnar shape having
the same diameter, and a diameter of a cross section taken along a
horizontal plane may be partially different. For example, a
diameter of an opening in a bottom surface of a insulating film may
be ten or more times as long as a diameter of an opening in a top
surface of the insulating film, as long as the diameter of the
opening in the top surface of the insulating film is longer than a
metal particle. In addition, a cross section taken along a
horizontal plane of the penetrating opening is not limited to a
circle and may also be elliptical or rectangular. When a cross
section taken along a horizontal plane of the penetrating opening
is elliptical, the length of a minor axis preferably ranges from 3
nm to 2000 nm. When a cross section taken along a horizontal plane
of the penetrating opening is rectangular, the length of a narrow
side preferably ranges from 3 nm to 2000 nm.
[0044] In addition, in order to lower electric resistance, a
diameter of an opening in a bottom surface of an insulating film
may be the same or may be longer than a diameter of one crystal so
that a crystal made of assembled metal particles is formed even in
the opening.
[0045] Since an opening shape according to the present invention is
formed by laser light, the shape can be complicated. According to
another feature of the present invention, a semiconductor device
comprises a first conductive layer; a plurality of penetrating
openings; an insulating film covering the first conductive layer;
and a second conductive layer in contact with the first conductive
layer through the plurality of penetrating openings, wherein the
second conductive layer contains conductive particles, and wherein
at least two penetrating openings among the plurality of
penetrating openings are connected to each other in the insulating
film.
[0046] In addition, an opening shape according to the present
invention is not limited to a columnar shape extended to a
direction of a film thickness (that is, a Z direction). According
to the other feature of the present invention, a semiconductor
device comprises a first conductive layer; a plurality of
penetrating openings; an insulating film covering the first
conductive layer; and a second conductive layer in contact with the
first conductive layer through the plurality of penetrating
openings, wherein the second conductive layer contains conductive
particles, and wherein a cross-sectional shape of the plurality of
penetrating openings is an L shape, a U shape, or a shape drawing
an arc.
[0047] In addition, according to the present invention, a
penetrating opening refers to a passage leading to upper and lower
layers sandwiching an insulating film and a passage extended to a
horizontal direction in the insulating film. For example, a
cross-sectional shape of the penetrating openings according to the
present invention includes an L shape, a U shape, a shape drawing
an arc, or the like. Even in the case of the openings having such a
complicated cross-sectional shape, the opening having a complicated
shape can be filled with a conductive material by adjusting
viscosity of the discharging material as long as a droplet
discharging method is used.
[0048] For example, according to the present invention, a plurality
of minute openings can be connected to each other in a plane in
contact with a conductive layer. Accordingly, a plurality of minute
openings can be provided to a top surface of an insulating film and
a contact area can be increased by connecting a plurality of
openings with holes in a lateral direction (holes extended to an X
direction or a Y direction) provided in vicinity of a bottom
surface of the insulating film. In addition, a plurality of
vertical holes (holes extended to a Z direction) is connected to
horizontal holes (holes extended to an X direction or a Y
direction) taken along a bottom surface of the insulating film;
therefore, an air escapeway can be provided in discharging droplets
and thus air bubbles can be prevented from remaining in the
openings.
[0049] In addition, according to the above each feature, the
semiconductor device includes at least one of an antenna, a CPU (a
central processing unit), and a memory. For example, according to
the present invention, high integration of an integrated circuit
having a multilayer wiring formed through penetrating openings can
be realized. Specifically, an integrated circuit having an antenna
and a memory for identification and management of goods,
merchandise, and people, typically a wireless chip (also referred
to as an ID tag, an IC tag, an IC chip, an RF (Radio Frequency)
tag, a wireless tag, an electronic tag, or RFID (Radio Frequency
Identification)) can be completed.
[0050] In addition, according to the above each feature, the
semiconductor device is a display device (an LCD panel or an EL
panel), a video camera, a digital camera, a personal computer, or a
portable information terminal. For example, according to the
present invention, an integrated circuit having a multilayer wiring
formed through penetrating openings can be manufactured in a
simplified process; thus, an electronic device provided with the
integrated circuit can be completed.
[0051] In addition, according to one feature of a manufacturing
method of the present invention to realize the above each feature,
a method for manufacturing a semiconductor device comprises the
steps of forming a first conductive layer; forming an insulating
film over the first conductive layer; forming a plurality of
penetrating openings in the insulating film by being selectively
irradiated with laser light; and forming a second conductive layer
in contact with the first conductive layer through the plurality of
penetrating openings by a droplet discharging method or a printing
method.
[0052] In addition, according to the above feature of the
manufacturing method, the step of forming the second conductive
layer includes heat treatment in which a surface of the second
conductive layer which is overlapped with the plurality of
penetrating openings and a surface of the second conductive layer
which is not overlapped with the plurality of penetrating openings
are formed in one side.
[0053] In addition, according to another feature of a manufacturing
method of the present invention, a method for manufacturing a
semiconductor device comprises the steps of forming a first
conductive layer; forming an insulating film over the first
conductive layer; forming a plurality of penetrating openings
different in depth in the insulating film by being selectively
irradiated with laser light; and forming a second conductive layer
that fills the plurality of penetrating openings by a droplet
discharging method or a printing method.
[0054] In addition, according to another feature of a manufacturing
method of the present invention, a method for manufacturing a
semiconductor device comprises the steps of forming a first
conductive layer; forming an insulating film over the first
conductive layer; forming a plurality of penetrating openings
different in depth in the insulating film by being selectively
irradiated with laser light; and forming a second conductive layer
by filling the plurality of penetrating openings with conductive
particles after discharging a liquid material having the conductive
particles into the plurality of penetrating openings by a droplet
discharging method.
[0055] In addition, according to each feature of the above
manufacturing methods, the plurality of penetrating openings is
formed by moving a focal position of laser light to an X direction,
a Y direction, or a Z direction.
[0056] Since the plurality of penetrating openings is formed by
moving a focal position of laser light, various openings can be
formed. According to each feature of the above manufacturing
methods, a cross-sectional shape of the plurality of the
penetrating openings is a columnar shape, an L shape, a U shape, or
a shape drawing an arc.
[0057] In addition, penetrating openings may be formed by forming a
closed pore (a pore extended to a Z direction) in a
light-transmitting insulating film by laser light in advance to
subsequently remove a surface layer by etching or rubbing.
[0058] According to another feature of a manufacturing method of
the present invention, a method for manufacturing a semiconductor
device comprises the steps of forming a first conductive layer;
forming an insulating film over the first conductive layer; forming
a closed pore in contact with the first conductive layer in the
insulating film by being selectively irradiated with laser light;
forming the closed pore into a penetrating opening simultaneously
with performing thin film process to the insulating film; and
forming a second conductive layer in contact with the first
conductive layer through the plurality of penetrating openings by a
droplet discharging method or a printing method. In other words, a
manufacturing method of the present invention, a method for
manufacturing a semiconductor device comprises the steps of forming
a first conductive layer on a substrate; forming an insulating film
on the first conductive layer; forming a plurality of pores in the
insulating film by being selectively irradiated with laser light;
removing upper regions of the insulating film of the plurality of
pores to form a plurality of openings; and forming a second
conductive layer in contact with the first conductive layer though
the plurality of openings by a droplet discharging method or a
printing method.
[0059] In addition, according to each feature of the above
manufacturing methods, a diameter of the penetrating openings is 3
nm to 2000 nm.
[0060] In addition, a method for manufacturing a semiconductor
device having a transistor using a semiconductor substrate is also
one feature of the present invention. According to the feature, the
method for manufacturing a semiconductor device having a transistor
comprises the steps of forming a first insulating film over a
semiconductor substrate; forming a second insulating film over the
first insulating film; forming a first penetrating opening that
reaches the first insulating film and a second penetrating opening
that reaches the semiconductor substrate in the second insulating
film by being selectively irradiated with laser light; and forming
a gate electrode in contact with the first insulating film through
the first penetrating opening and an electrode in contact with the
semiconductor substrate through the second penetrating opening by a
droplet discharging method.
[0061] In addition, a method for manufacturing a top gate thin film
transistor (TFT) formed over a substrate having an insulating
surface is also one feature of the present invention. According to
the feature, the method for manufacturing a semiconductor device,
having a thin film transistor, comprises the steps of forming a
semiconductor layer over a substrate having an insulating surface;
forming a first insulating film covering the semiconductor layer in
the second insulating film by being selectively irradiated with
laser light; forming a second insulating film; forming a first
penetrating opening that reaches the first insulating film and a
second penetrating opening that reaches the semiconductor layer;
and forming a gate electrode in contact with the first insulating
film through the first penetrating opening and an electrode in
contact with the semiconductor layer through the second penetrating
opening by a droplet discharging method.
[0062] Note that the first insulating film is a gate insulating
film. In addition, the second insulating film is an interlayer
insulating film.
[0063] In addition, a method for manufacturing a bottom gate thin
film transistor (TFT) formed over a substrate having an insulating
surface is also one feature of the present invention. According to
the feature, the method for manufacturing a semiconductor device,
having a thin film transistor, comprises the steps of forming a
first insulating film over a substrate having an insulating
surface; forming a semiconductor layer over the first insulating
film; forming a second insulating film above the semiconductor
layer; forming a first penetrating opening in the first insulating
film and the second insulating film and a second penetrating
opening that reaches the semiconductor layer in the second
insulating film by being selectively irradiated with laser light;
and forming a gate electrode through the first penetrating opening
and an electrode in contact with the semiconductor layer through
the second penetrating opening by a droplet discharging method,
wherein part of the first penetrating opening is formed below the
semiconductor layer, and wherein the first insulating film between
the first penetrating opening and the semiconductor layer is a gate
insulating film. In other words, a method for manufacturing a
semiconductor device comprises the steps of forming a first
insulating film on a substrate; forming a semiconductor layer on
the first insulating film; forming a second insulating film on the
semiconductor layer; forming a pore in the first insulating film
and an opening that reaches the semiconductor layer in the second
insulating film by being selectively irradiated with laser light;
and forming a gate electrode through the pore and an electrode in
contact with the semiconductor layer through the opening by a
droplet discharging method or a printing method.
[0064] According to the above feature of the manufacturing method,
the first penetrating opening is formed by laser light irradiation
from the side of the substrate having an insulating surface or by
laser light irradiation from the side of the second insulating
film.
[0065] In addition, according to the above feature of the
manufacturing method, the second insulating film is an interlayer
insulating film.
[0066] In addition, according to the above feature of the
manufacturing method, the first penetrating opening is an opening
in which an opening in a Z direction and an opening in an X
direction or a Y direction are connected. According to the above
manufacturing method of the present invention, the second
insulating film is formed first, and then, an opening like a tunnel
is formed by laser light and the opening is filled with a
conductive material to form a gate electrode. Since the position of
the gate electrode in a depth direction can be set arbitrarily with
the use of laser light, it is also possible to obtain a thin film
of the gate insulating film. Moreover, the gate electrode can also
be formed without damaging the gate insulating film.
[0067] In addition, according to the above feature of the
manufacturing method, a diameter of the first penetrating opening
is 3 nm or more and 2000 nm or less.
[0068] In addition according to each feature of the manufacturing
method, the laser light oscillates when a pulse width of the laser
light is 1 femtosecond or more and 10 picoseconds or less. High
intensity multiphoton absorption can occur can be obtained by
having the pulse width in the range of 1 femtosecond or more and 10
picoseconds or less. Multiphoton absorption does not occur when a
laser beam has a pulse width of several tens picoseconds longer
than 10 picoseconds. Moreover, the laser light has a fundamental
wave emitted from a laser oscillator the laser repetition frequency
of which is 10 MHz or more.
[0069] In addition, according to the present invention, a
semiconductor film containing silicon as its main component, a
semiconductor film containing an organic material as its main
component, or a semiconductor film containing metal oxide as its
main component can be used for a semiconductor layer. As for the
semiconductor film containing silicon as its main component, an
amorphous semiconductor film, a semiconductor film including a
crystalline structure, a compound semiconductor film including an
amorphous structure, or the like, specifically amorphous silicon,
microcrystalline silicon, polycrystalline silicon, single crystal
silicon, or the like can be used. As for the semiconductor film
containing an organic material as its main component, a
semiconductor film containing as its main component a material
comprising carbon or allotropes (aside from a diamond) of carbon at
a quantity, at least having a material which has charge carrier
mobility of 10.sup.-3 cm.sup.2/Vs or more in room temperature
(20.degree. C.), can be used by being combined with other elements.
For example, an aromatic of .pi. electron conjugate system, a chain
compound, an organic, or an organosilicon compound can be used.
Specifically, pentacene, tetracene, thiophen oligomers, phenylenes,
a phthalocyanine compound, poly acetylenes, polythiophenes, a
cyanine dye, and the like are given as examples. As for the
semiconductor film containing metal oxide as its main component,
zinc oxide (ZnO); oxide of zinc, gallium, and indium
(In--Ga--Zn--O); or the like can be used.
[0070] In addition, a semiconductor device according to the present
invention may be provided with a protective circuit (for example, a
protection diode) for preventing electrostatic discharge
damage.
[0071] In addition, regardless of a TFT structure and a transistor
structure, the present invention can be applied and, for example, a
top gate TFT, a bottom gate (reverse stagger) TFT, or a forward
stagger TFT can be used. Moreover, not limiting to a transistor
having a single gate structure, a multi-gate transistor having a
plurality of channel-forming regions, for example, a double gate
transistor may be used.
[0072] According to the present invention, steps needed to process
a wiring in forming a multilayer wiring can be simplified. Further,
high integration of a circuit can also be realized.
[0073] In addition, a plurality of contact holes different in depth
can be realized in a simplified process.
[0074] In addition, since a fundamental wave the wavelength of
which is approximately 1 .mu.m is used according to the present
invention, a contact hole can be formed without damaging an element
and a substrate because the fundamental wave is not absorbed by the
element and substrate. Therefore, a semiconductor device can be
manufactured by using an element that is easily affected by heat or
an etching solution or a film substrate that is easily affected by
heat or an etching solution.
[0075] These and other objects, features and advantages of the
present invention will become more apparent upon reading of the
following detailed description along with the accompanied
drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0076] In the accompanying drawings:
[0077] FIGS. 1A to 1D are process cross-sectional views and a top
view according to the present invention (Embodiment Mode 1);
[0078] FIGS. 2A and 2B are cross-sectional views explaining a
manufacturing process of an opening according to the present
invention (Embodiment Mode 1);
[0079] FIGS. 3A to 3C are cross-sectional views and a top view
showing one example of an opening shape according to the present
invention Embodiment Mode 2);
[0080] FIGS. 4A to 4C are cross-sectional views explaining a
manufacturing process of an opening according to the present
invention Embodiment Mode 3);
[0081] FIGS. 5A to 5C are cross-sectional views and a top view
showing one example of an opening shape according to the present
invention (Embodiment Mode 4);
[0082] FIGS. 6A to 6D are cross-sectional views showing a
manufacturing process of a bottom gate TFT (Embodiment Mode 5);
[0083] FIGS. 7A to 7D are cross-sectional views showing a
manufacturing process of a top gate TFT (Embodiment Mode 6);
[0084] FIG. 8 is a cross-sectional view showing a structure of an
active matrix liquid crystal display device (Embodiment Mode
6);
[0085] FIG. 9 is a cross-sectional view showing a structure of an
active matrix EL display device (Embodiment Mode 6);
[0086] FIG. 10 is a diagram explaining a laser beam direct writing
system applicable to the present invention (Embodiment Mode 1);
[0087] FIG. 11 is a diagram explaining a droplet discharging device
applicable to the present invention (Embodiment Mode 1);
[0088] FIGS. 12A to 12D are cross-sectional views showing a method
for manufacturing a semiconductor device (Embodiment 1);
[0089] FIG. 13 is a perspective view of a semiconductor device
(Embodiment 1);
[0090] FIG. 14 is a top view showing a module (Embodiment 2);
[0091] FIGS. 15A and 15B are a block diagram and a perspective view
of a television device (Embodiment 4);
[0092] FIGS. 16A to 16E are views each showing one example of an
electronic device (Embodiment 5);
[0093] FIG. 17 is one example of a cross-sectional view showing a
structure according to the present invention (Embodiment 6);
[0094] FIGS. 18A to 18F are perspective views explaining
application examples of a semiconductor device (Embodiment 6);
and
[0095] FIGS. 19A to 19C are cross-sectional views showing a
conventional example.
DETAILED DESCRIPTION OF THE INVENTION
[0096] Embodiment Mode of the present invention will be described
below with reference to the accompanying drawings. However, it is
to be easily understood that various changes and modifications will
be apparent to those skilled in the art. Therefore, unless such
changes and modifications depart from the invention, they should be
construed as being included therein. Note that reference numerals
denoting the identical portions are the same in all figures.
Embodiment Mode 1
[0097] In this embodiment mode, a method for forming a contact hole
in a first conductive layer and a method for forming a second
conductive layer electrically connected to the first conductive
layer through the contact hole will be explained with reference to
FIGS. 1A to 1D, FIGS. 2A and 2B, FIG. 10, and FIG. 11.
[0098] First, a base insulating film 11 is formed over a substrate
10 having an insulating surface, and a first conductive layer 12 is
formed over the base insulating film 11. Next, an insulating film
13 covering the first conductive layer 12 is formed. A
cross-sectional view of this stage is shown in FIG. 1A.
[0099] Note that a glass substrate or quartz substrate having light
transparency is preferably used as the substrate 10 having an
insulating surface.
[0100] In addition, as for the base insulating film 11, a base film
made of an insulating film such as a silicon oxide film, a silicon
nitride film, or a silicon oxynitride film is formed. Herein, an
example where a two-layer structure is used as a base film is
shown; however, the insulating film may be a single layer film or
may have a structure where two or more layers are stacked. Note
that the base insulating film is not particularly necessary.
[0101] In addition, as for the first conductive layer 12, a
conductive film 100 nm to 600 nm in thickness is formed by a
sputtering method and then patterning is performed with the use of
a photolithography technique. Note that the conductive film is
formed of one or more elements of Ta, W, Ti, Mo, Al, Cu, and Si, or
a single layer or a stacked layer of an alloy material or a
compound material containing the element as its main component.
Herein, an example where the first conductive layer is formed with
the use of a photolithography technique is shown; however, the
first conductive layer 12 may be formed by droplet discharging
method, a printing method, or electroless plating without being
particularly limited. It is preferable for the first conductive
layer 12 to use a material that reflects and hardly absorbs laser
light used in the subsequent opening process.
[0102] Moreover, the first conductive layer 12 may also be formed
using a transparent conductive material such as ITO, IZO, or ITSO.
It is preferable to use a material that transmits and hardly
absorbs laser light used in the subsequent opening process.
[0103] In addition, the insulating film 13 is formed using an
insulating material that transmits and hardly absorbs laser light
used in the subsequent opening process, for example, an insulating
film such as a silicon oxide film, a silicon nitride film, or a
silicon oxynitride film. Moreover, the insulating film 13 may be
formed using an insulating film where a framework structure is
formed by the bond between silicon (Si) and oxygen (O), which is
obtained by a coating method. Further, as for the insulating film
13, the following can also be used: PSG (phosphosilicate glass) in
which phosphorus is added to silicon dioxide; BPSG
(borophosphosilicate glass) in which phosphorus and boron are added
to silicon dioxide; SiOF in which fluorine is added to silicon
dioxide; polyimide; aromatic ether typified by polyfluoroether in
which polyallylether or fluorine is added; aromatic hydrocarbon; a
cyclobutane derivative typified by BCB (Benzocyclobutene); or the
like.
[0104] Although a planar insulating film is shown as the insulating
film 13 in FIG. 1A, an inorganic insulating film obtained by a CVD
method or a sputtering method may be used without being
particularly limited. A plurality of openings can be formed using
laser light according to the present invention even when the
insulating film 13 does not have planarity.
[0105] In this embodiment mode, the insulating film 13 is formed by
performing drying and baking after coating or discharging the
material with the use of a coating method or a droplet discharging
method.
[0106] Next, the insulating film 13 is irradiated with laser light
to form a plurality of penetrating openings as shown in FIG. 1B.
Herein, laser light emitted from an ultrashort pulsed laser is used
as the laser light. When an ultrashort pulsed laser is condensed in
a light-transmitting material, multiphoton absorption can occur
only at a condensed spot where the ultrashort pulsed laser is
condensed, a closed pore can be formed, and one penetrating opening
can be formed by moving the condensed spot. When the pulsed width
of the laser light is 10.sup.-4 seconds to 10.sup.-2 seconds, the
laser light is not absorbed by the insulating film 13. However,
when multiphoton absorption occurs by irradiating the insulating
film 13 with laser light the pulse width of which is extremely
short (picoseconds (10.sup.-12 seconds) or femtoseconds (10.sup.-16
seconds)), the laser light can be absorbed by the insulating film
13.
[0107] An ultrashort pulsed laser oscillator 101 is a laser
oscillator with a pulse width of femtoseconds (10.sup.-15 seconds).
The ultrashort pulsed laser oscillator 101 may be a laser having a
medium of a crystal of sapphire, YAG, ceramic YAG, ceramic
Y.sub.2O.sub.3, KGW (potassium gadolinium tungsten),
Mg.sub.2SiO.sub.4, YLF, YVO.sub.4, GdVO.sub.4, or the like, each of
which is doped with one or a plurality of Nd, Yb, Cr, Ti, Ho, and
Er. Laser light emitted from the ultrashort pulsed laser oscillator
101 is reflected by a mirror 102, and then condensed in a sample
104, herein the insulating film 13 provided over the substrate, by
an objective lens 15 with a high numerical aperture (see FIG. 2A).
As a result, a pore can be formed in the vicinity of a condensed
spot in the insulating film. A desired opening is formed in the
insulating film 13 by moving the condensed spot with the use of an
XYZ stage 105. FIG. 2B shows a cross-sectional view in the middle
of forming an opening. A non-penetrating opening is shown in FIG.
2B as a pore 17.
[0108] Note that an ultrashort pulsed laser in this specification
is a laser beam oscillated from a solid-state laser where a pulse
width is 1 femtosecond or more and 10 picoseconds or less. Note
that a peak power of laser light according to the present invention
ranges from 1 GW/cm.sup.2 to 1 TW/cm.sup.2.
[0109] The ultrashort pulsed laser allows processing to be
performed only at the beam center with high energy density;
therefore, fine processing, that is, a laser wavelength or less can
be processed using the ultrashort pulsed laser having a laser
wavelength or less that is not easily processed by a normal
laser.
[0110] The insulating film 13 needs to be formed using a material
that transmits light having the wavelength of the ultrashort pulsed
laser, namely, a material in which light having the wavelength of
the ultrashort pulsed laser is not absorbed, and more specifically,
a material having a higher energy gap than the ultrashort pulsed
laser. When the ultrashort pulsed laser is condensed in the
material that transmits light, multiphoton absorption can occur
only at a condensed spot where the ultrashort pulsed laser is
condensed and a pore can be formed. Note that the multiphoton
absorption is a process where two or more photons are absorbed
concurrently to make a transition to an eigenstate that corresponds
to the sum of energy of the photons. This transition allows light
in a wavelength range that is not absorbed to be absorbed;
therefore, a pore can be formed in a condensed spot having a
sufficiently high light energy density. Note that the term
"concurrently" herein referred means that two phenomena occur
within 10.sup.-14 seconds.
[0111] A laser beam direct writing system is described with
reference to FIG. 10. As shown in FIG. 10, a laser beam direct
writing system 1001 has a personal computer (hereinafter referred
to as a PC) 1002 for carrying out various controls in irradiation
of a laser beam; a laser oscillator 1003 for outputting a laser
beam; a power supply 1004 of the laser oscillator 1003; an optical
system (ND filter) 1005 for attenuating a laser beam; an
acousto-optic modulator (AOM) 1006 for modulating the intensity of
a laser beam; an optical system 1007 constituted by a lens for
magnifying or reducing the cross-sectional surface of a laser beam,
a mirror for changing the optical path, and the like; a substrate
moving mechanism 1009 having an X stage and a Y stage; a D/A
converter portion 1010 for digital-analog converting the control
data outputted from the PC; a driver 1011 for controlling the
acousto-optic modulator 1006 in accordance with an analog voltage
outputted from the D/A converter portion; and a driver 1012 for
outputting a driving signal for driving the substrate moving
mechanism 1009.
[0112] The laser oscillator 1003 is a laser oscillator with a pulse
width of femtoseconds (10.sup.-15 seconds).
[0113] Next, a method for irradiating a laser beam using the laser
beam direct writing system will be explained. When a substrate 1008
is placed on the substrate moving mechanism 1009, the PC 1002
detects the position of a marker formed on the substrate by using a
camera (not shown). Then, the PC 1002 generates movement data for
moving the substrate moving mechanism 1009 in accordance with the
detected positional data of the marker and the preprogrammed
writing pattern data. Subsequently, the PC 1002 controls the amount
of light outputted from the acousto-optic modulator 1006 through
the driver 1011; therefore, and a laser beam outputted from the
laser oscillator 1003 is attenuated by the optical system 1005 and
then controlled in quantity by the acousto-optic modulator 1006 to
have a predetermined quantity of light.
[0114] Meanwhile, the optical path and beam shape of the laser beam
outputted from the acousto-optic modulator 1006 is changed by the
optical system 1007 and the laser beam is condensed by the lens.
Then, an insulating film over the substrate is irradiated with the
laser beam to form a pore. At this time, the substrate moving
mechanism 1009 is controlled to move in the Z direction in
accordance with the movement data generated by the PC 1002. As a
result, a predetermined area is irradiated with the laser beam, and
the pore is connected to the Z direction to form an opening in the
insulating film. When the substrate moving mechanism 1009 is
controlled to move in the X direction and the Y direction, a pore
is formed in the insulating film in a direction horizontal to the
substrate plane.
[0115] A laser beam with a shorter wavelength can be condensed to
have a shorter diameter of beam. Accordingly, an opening with small
diameter can be formed by irradiation of a laser beam with a short
wavelength.
[0116] The laser beam spot on the surface of the pattern can be
processed by the optical system so as to have a dotted shape, a
circular shape, an elliptical shape, a rectangular shape, or a
linear shape (to be exact, elongated rectangular shape).
[0117] Although, herein, the substrate is selectively irradiated
with the laser beam while being moved, the present invention is not
limited to this and the substrate can be irradiated with the laser
beam while scanning the laser beam in the Z direction, X direction,
and Y direction. In this case, a polygon mirror, a galvanometer
mirror, or an acousto-optic deflector (AOD) is preferably used for
the optical system 1007.
[0118] Subsequently, a second conductive layer 19 is formed by
discharging a composition containing conductive particles by a
droplet discharging method so that a plurality of penetrating
openings 16 is overlapped (see FIG. 1C). The second conductive
layer 19 is formed using a droplet discharging means 18. The
droplet discharging means 18 is a collective term of means for
discharging a droplet, such as a nozzle having an outlet of a
composition, and a head having one or more nozzles. The droplet
discharging means 18 has a nozzle with a diameter of 0.02 .mu.m to
100 .mu.m (preferably, 30 .mu.m or less), and the discharge amount
of a composition discharged from the nozzle is 0.001 pl to 100 pl
(preferably, 10 pl or less). The discharge amount increases in
proportion to the diameter of the nozzle. The distance between an
object and the outlet of the nozzle is preferably as short as
possible, and reduced to approximately 0.1 mm to 3 mm (preferably,
1 mm or less) in order to discharge the composition onto a desired
area.
[0119] As for the composition discharged from the outlet, a
solution where conductive particles are dissolved or dispersed in a
solvent is used. The conductive particles may be a metal such as
Ag, Au, Cu, Ni, Pt, Pd, Ir, Rh, W, and Al; a metal sulfide such as
Cd and Zn; an oxide such as Fe, Ti, Si, Ge, Zr, and Ba; fine
particles such as silver halide particles; or dispersed
nanoparticles. However, the composition discharged from the outlet
is preferably a solution where gold, silver, or copper is dissolved
or dispersed in a solvent in view of the resistivity. More
preferably, silver or copper that has low resistance is used. Note
that if silver or copper is used, a barrier film is preferably
provided for preventing impurities from entering. As for the
solvent, esters such as butyl acetate and ethyl acetate, alcohols
such as isopropyl alcohol and ethyl alcohol, or an organic solvent
such as methyl ethyl ketone and acetone may be used. The viscosity
of the composition is preferably 50 cp or less for preventing
drying and for allowing the composition to be discharged smoothly
from the outlet. The surface tension of the composition is
preferably 40 mN/m or less. However, the viscosity and the like of
the composition may be set appropriately in accordance with the
solvent or the application.
[0120] It is preferable that the diameter of the conductive
particles is as small as possible in order to prevent each nozzle
from clogging or to make fine patterns, and more preferably, each
particle has a diameter of 0.1 .mu.m or less, though it depends on
the diameter of each nozzle or the desired pattern shape. The
composition is formed by a known method such as an electrolytic
method, an atomization method, and wet reduction, and the particle
size is generally approximately 0.01 .mu.m to 10 .mu.m. Note that
if the composition is formed by a gas evaporation method,
nanoparticles protected with a dispersant are as fine as
approximately 7 nm, and the nanoparticles are dispersed stably at
room temperature and behave similarly to liquid without aggregation
in a solvent when each of them is protected with a coating.
Therefore, it is preferable to use a coating.
[0121] Here, a droplet discharging device will be explained with
reference to FIG. 11. As the each heads 1105 and 1112 of the
droplet discharging means is connected to control means 1107 and
the control means 1107 is controlled by a computer 1110, a pattern
that has been programmed in advance can be plotted. The timing of
plotting may be taken with reference to a marker 1111 formed over a
substrate 1100, for example. Alternatively, a reference point may
be fixed with an edge of the substrate 1100 as a reference. The
reference point is detected by an imaging means 1104 such as an
image sensor using a charge coupled device (CCD) or a complementary
metal-oxide semiconductor (CMOS), and the computer 1110 recognizes
a digital signal converted by an image processing means 1109 to
generate a control signal, which is transmitted to a control means
1107. Of course, information of a pattern to be formed over the
substrate 1100 is placed in a recording medium 1108. Based on this
information, the control signal can be transmitted to the control
means 1107 and each head 1105 and 1112 of the droplet discharging
means 1103 can be controlled individually. A material to be
discharged is supplied to the heads 1105 and 1112 from material
supply sources 1113 and 1114 through a piping. Although the
longitudinal length of the heads 1105 and 1112 arranged in parallel
of the droplet discharging means 1103 corresponds to the width of
the substrate in FIG. 11, the droplet discharging device can form a
pattern over a large-sized substrate wider than the longitudinal
length of the heads 1105 and 1112 by scanning the beads repeatedly.
In that case, the heads 1105 and 1112 can be scanned freely over
the substrate in directions denoted by arrows so that a region to
be written can be freely set. Accordingly, a plurality of same
patterns can be written over a substrate.
[0122] Next, as well as baking and removing the wiring material by
being irradiated with laser light or by heat treatment, any one or
a plurality of reaction of fusing, sintering, and welding of
conductive particles is performed.
[0123] In addition, FIG. 1D shows one example of a top view showing
after forming the second conductive layer 19. Note that FIG. 1C
corresponds to a cross-sectional view taken along a broken line A-B
in FIG. 1D.
[0124] As shown in FIG. 1D, a number of penetrating openings
(herein, 10 penetrating openings) are provided, and the second
conductive layer 19 is electrically connected to the first
conductive layer 12 through the openings. Note that the number of
the openings is not limited to ten, of course, and disposition of
the openings is not particularly limited.
[0125] In addition, an insulator between the minute penetrating
openings 16 serves as a spacer, which prevents a surface of the
second conductive layer from generating a depression. The second
conductive layer 19 can have a uniform wiring width. A width of the
second conductive layer D and a diameter of each of the plurality
of penetrating openings W satisfy 2D<W (FIG. 1D).
Embodiment Mode 2
[0126] In this embodiment mode, an example of an opening the
cross-sectional shape of which differs from Embodiment Mode 1 will
be shown with reference to FIGS. 3A to 3C. Portions different from
Embodiment Mode 1 will be explained in detail and portions
identical with FIGS. 1A to 1D in FIGS. 3A to 3C are denoted by the
same reference numerals.
[0127] Note that a cross-sectional shape of an opening in FIGS. 1A
to 1D is shown in a columnar shape; however, the present invention
is not limited thereto and an opening the shape of which has a
structure in which a plurality of openings is connected to each
other in an insulating film as shown in FIG. 3 may be employed.
[0128] First, as well as in Embodiment Mode 1, a base insulating
film 11 and a first conductive layer 12 are formed over a substrate
10 having an insulating surface.
[0129] Next, after forming an insulating film made of a material
that is light transmitting to laser light having a pulse width of
10.sup.-4 seconds to 10.sup.-2 seconds, an insulating film 23
having a penetrating opening 26 is obtained by irradiation of
ultrashort pulsed laser light. When an ultrashort pulsed laser is
condensed in an insulating film, multiphoton absorption can occur
only at a condensed spot where the ultrashort pulsed laser is
condensed, a closed pore can be formed, and one penetrating opening
can be formed by moving the condensed spot. When the pulsed width
of the laser light is 10.sup.-4 seconds to 10.sup.-2 seconds, the
laser light is not absorbed by the insulating film 23. However,
when multiphoton absorption occurs by irradiating the insulating
film 23 with laser light the pulse width of which is extremely
short (picoseconds or femtoseconds), the laser light can be
absorbed by the insulating film 23.
[0130] Note that forming an opening by using laser light is
explained in detail in Embodiment Mode 1; therefore, only brief
explanation is given here.
[0131] The opening 26 having a complicated cross-sectional shape as
shown in FIG. 3A can be formed by moving a focal position of laser
light to a Z direction, an X direction or a Y direction during
laser light irradiation.
[0132] Next, a second conductive layer 29 is formed by discharging
a composition containing conductive particles so as to overlap with
the opening 26 with the use of a droplet discharging method (see
FIG. 3B). The second conductive layer 29 is formed by using a
droplet discharging means 28.
[0133] When a composition is discharged into one opening in the
insulating film 23 in forming the second conductive layer 29, air
inside the opening is pushed out of the other openings. With such a
structure where a plurality of openings is connected in an
insulating film, the interior of an opening having a complicated
shape can be filled with the conductive particles without leaving a
bubble.
[0134] Next, baking is performed by heat treatment or laser light
irradiation and removal is also performed, and any one or a plural
reaction of fusing, sintering, and welding of the conductive
particles is performed.
[0135] In performing heat treatment, the interior of an opening
having a complicated shape may be filled with the conductive
particles without leaving a bubble after pushing the bubble to the
outside air out of a plurality of openings.
[0136] In addition, FIG. 3C shows one example of a top view in a
state after forming the second conductive layer 29. Note that FIG.
3B corresponds to a cross-sectional view taken along a broken line
A-B in FIG. 3C.
[0137] Although the number of openings is six as shown in FIG. 3C,
the three openings are each connected in the insulating film, which
can be referred to as total two openings having a complicated
shape. As compared with Embodiment Mode 1, a few openings are
provided on an insulating surface; however, a contact area between
the first conductive layer and the second conductive layer is
larger in this embodiment mode. Needless to say that the number of
openings is not limited to two and disposition of an opening is not
limited particularly.
[0138] In addition, an insulator between the minute penetrating
openings 26 serves as a spacer that holds a surface position of the
second conductive layer, which prevents the surface of the second
conductive layer from generating a depression. Moreover, a wiring
width of the second conductive layer 29 can be made uniform.
[0139] In addition, this embodiment mode can be arbitrarily
combined with Embodiment Mode 1.
Embodiment Mode 3
[0140] In this embodiment mode, an example of forming a plurality
of openings with the combination of laser light and etching will be
explained with reference to FIGS. 4A to 4C. Portions different from
Embodiment Mode 1 will be explained in detail, and portions
identical with FIGS. 1A to 1D are denoted by the same reference
numerals in FIGS. 4A to 4C.
[0141] After forming an insulating film made of a material that is
light transmitting to laser light having a pulse width of 10.sup.-4
seconds to 10.sup.-2 seconds, an insulating film 33 having a closed
pore 37 is obtained by irradiation of ultrashort pulsed laser
light. When an ultrashort pulsed laser is condensed in the
insulating film, multiphoton absorption can occur only at a
condensed spot where the ultrashort pulsed laser is condensed, a
closed pore can be formed, and one penetrating opening can be
formed by moving the condensed spot. When the pulsed width of the
laser light is 10.sup.-4 seconds to 10.sup.-2 seconds, the laser
light is not absorbed by the insulating film 33. However, when
multiphoton absorption occurs by irradiating the insulating film 33
with laser light the pulse width of which is extremely short
(picoseconds or femtoseconds), the laser light can be absorbed by
the insulating film 33.
[0142] Note that forming an opening by using laser light is
explained in detail in Embodiment Mode 1; therefore, only brief
explanation is given here.
[0143] As shown in FIG. 4A, a focus of laser light is formed by an
optical system 15, which is formed by moving a focal position
during laser light irradiation. The closed pore 37 is formed by
forming a focus of laser light with the use of an optical system 15
and by moving a focal position during the laser light
irradiation
[0144] Next, as shown in FIG. 4B, a surface of the insulating film
is etched to obtain a thin film. The insulating film above the
closed pore 37 is removed by this etching so that an opening 36
penetrating through the closed pore 37 can be formed. An insulating
film 34 having a plurality of the penetrating openings 36 is
obtained at this stage. Note that a dotted line shown in FIG. 4B
shows a surface of the insulating film before etching.
[0145] In addition, a thin film of the insulating film may be
obtained by polishing (such as CMP) instead of etching.
[0146] Next, a second conductive layer 39 is formed by discharging
a composition containing conductive particles so as to overlap with
a plurality of the penetrating openings 36 with the use of a
droplet discharging method (see FIG. 4C). The second conductive
layer 39 is formed by using a droplet discharging means 38.
[0147] Then, baking is performed by heat treatment or laser light
irradiation and removal is also performed, and any one or a plural
reaction of fusing, sintering, and welding of the conductive
particles is performed.
[0148] According to this embodiment mode, the penetrating opening
having a comparatively shallow depth can be formed in the
insulating film.
[0149] In addition, this embodiment mode can be arbitrarily
combined with Embodiment Mode 1 or Embodiment Mode 2.
Embodiment Mode 4
[0150] In this embodiment mode, an example different from
Embodiment Mode 1 in a cross-sectional shape will be shown in FIGS.
5A to 5C. Portions different from Embodiment Mode 1 will be
explained in detail, and portions identical with FIGS. 1A to 1D are
denoted by the same reference numerals in FIGS. 5A to 5C.
[0151] In this embodiment mode, an example in which a
cross-sectional shape of an opening is curved is shown.
[0152] First, as well as in Embodiment Mode 1, a base insulating
film 11 and a first conductive layer 12 are formed over a substrate
10 having an insulating surface.
[0153] Next, after forming an insulating film made of a material
that is light transmitting to laser light, an insulating film 43
having a penetrating opening 46 is obtained by irradiation of
ultrashort pulsed laser light. When the pulsed width of the laser
light is 10.sup.-4 seconds to 10.sup.-2 seconds, the laser light is
not absorbed by the insulating film 43. However, when multiphoton
absorption occurs by irradiating the insulating film 43 with laser
light the pulse width of which is extremely short (picoseconds or
femtoseconds), the laser light can be absorbed by the insulating
film 43.
[0154] Note that forming an opening by using laser light is
explained in detail in Embodiment Mode 1; therefore, only brief
explanation is given here.
[0155] The opening 46 having a curved cross-sectional shape as
shown in FIG. 5A can be formed by moving a focal position to an X
direction or a Y direction during laser light irradiation and then
moving to a Z direction and repeatedly moving again to the X
direction or Y direction.
[0156] Note that a side of the first conductive layer 12 of the
opening 46 having a curved cross-sectional shape is exposed.
[0157] Next a second conductive layer 49 is formed by discharging a
composition containing conductive particles so as to overlap with a
plurality of the penetrating openings 46 with the use of a droplet
discharging method (see FIG. 5B). The second conductive layer 49 is
formed by using a droplet discharging means 48. In this embodiment
mode, a cross-sectional shape of the opening is curved; therefore,
the interior of the opening can be filled smoothly with the
composition containing conductive particles.
[0158] Then, baking is performed by heat treatment or laser light
irradiation and removal is also performed, and any one or a plural
reaction of fusing, sintering, and welding of the conductive
particles is performed.
[0159] In addition, FIG. 5C shows one example of a top view in a
state after forming the second conductive layer 49. Note that FIG.
5B corresponds to a cross-sectional view taken along a broken line
A-B in FIG. 5C. Moreover, FIG. 5C shows an example in which two
kinds of openings in an elliptical shape and a circular shape are
formed. In other words, three elliptical openings and one circular
opening, that is, total four openings are formed. Thus, according
to the present invention, a variety of openings can be formed by
adjusting a focal position of laser light arbitrarily.
[0160] According to this embodiment mode, a cross-sectional shape
of the penetrating opening 46 is curved so that the opening can be
conducted electrically with the second conductive layer 49 on the
side surface of the first conductive layer 12. Therefore, the first
conductive layer 12 and the second conductive layer 49 are disposed
so as not to overlap with each other. Parasitic capacitance formed
between the first conductive layer 12 and the second conductive
layer 49 can be reduced by having such a disposition.
[0161] In addition, this embodiment mode can be arbitrarily
combined with Embodiment Mode 1, Embodiment Mode 2, or Embodiment
Mode 3.
Embodiment Mode 5
[0162] In this embodiment mode, an example of forming a TFT with
the use of an opening formed by using laser light according to the
present invention is shown with reference to FIGS. 6A to 6D.
[0163] First, a base insulating film 201 is formed over a substrate
200 having an insulating surface. As for the substrate 200 having
an insulating surface, a light-transmitting substrate, for example,
a glass substrate, a crystalline glass substrate, or a plastic
substrate can be used. As for the plastic substrate, a plastic film
substrate, for example, a plastic substrate of poly(ethylene
terephthalate) (PET), poly(ether sulfone) (PES), poly(ethylene
naphthalate) (PEN), polycarbonate (PC), nylon, polyetheretherketone
(PEEK), polysulfone (PSF), poly(ether imide) (PEI), polyarylate
(PAR), polybutylene terephthalate) (PBT), or the like is
preferable. In addition, a plastic substrate having heat
resistance, for example, a plastic substrate in which a material
where inorganic particles of several nm diameters are dispersed in
an organic polymer matrix is processed in a sheet may also be
used.
[0164] As for the base insulating film 201, an insulating film such
as a silicon oxide film, a silicon nitride film, or a silicon
oxynitride (SiO.sub.xN.sub.y) film is used. As a typical example of
the base insulating film 11, a two-layer structure in which a
silicon nitride oxide film 50 nm to 100 nm in thickness, deposited
with the use of SiH.sub.4, NH.sub.3, and N.sub.2O as a reactive
gas, and silicon oxynitride film 100 nm to 150 nm in thickness,
deposited with the use of SiH.sub.4 and N.sub.2O as a reactive gas,
are stacked is employed. In addition, a silicon nitride film (SiN
film) or a silicon oxynitride film (SiN.sub.xO.sub.y film (X>Y))
the film thickness of which is 10 nm or less is preferably used as
one layer of the base insulating film 201. Moreover, a three-layer
structure in which a silicon nitride oxide film, a silicon
oxynitride film, and a silicon nitride film are sequentially
stacked may also be employed. An example of forming the base
insulating film 201 is shown here; however, the base insulating
film 201 is not necessarily provided if not necessary.
[0165] Next, a first insulating film 202 serving as a gate
insulating film is formed. As for the first insulating film 202, it
is preferable to use a material that transmits and hardly absorbs a
fundamental wave of laser light used in the following opening
process. As for the first insulating film 202, an insulating film
such as a silicon oxide film, a silicon nitride film, or a silicon
oxynitride film is used. In addition, as for the first insulating
film 202, a film that is obtained by coating and baking a solution
containing polysilazane or a siloxane polymer, a photo-curing
organic resin film, a thermosetting organic resin film, or the like
may also be used.
[0166] Then, a semiconductor film is formed. The semiconductor film
is formed with an amorphous semiconductor film or a
microcrystalline semiconductor film that is manufactured by a
vapor-phase growth method, a sputtering method, or a thermal CVD
method with the use of a semiconductor material gas typified by
silane and germanium. In this embodiment mode, an example of using
an amorphous silicon film as the semiconductor film is shown. In
addition, as for the semiconductor film, ZnO or oxide of zinc
gallium indium manufactured by a sputtering method or a PLD (Pulsed
Laser Deposition) method may also be used; however, in that case,
the gate insulating film is preferably an oxide containing aluminum
or titanium. Moreover, as for the semiconductor film, an organic
material such as pentacene, tetracene, thiophen oligomers,
phenylenes, a phthalocyanine compound, poly acetylenes,
polythiophenes, or a cyanine dye, manufactured by a coating method,
a droplet discharging method, or a vapor deposition method, may
also be used.
[0167] Subsequently, a conductive semiconductor film is formed. As
for the conductive semiconductor film, a semiconductor film
exhibiting n-type or p-type conductivity in which n-type or p-type
impurities are added is used. The n-type semiconductor film may be
formed by a PCVD method with the use of a silane gas and a
phosphine gas. In this embodiment mode, an example of using a
silicon film containing phosphorus is shown as the conductive
semiconductor film. Note that, in the case of using an organic
material such as pentacene as the semiconductor film, a
charge-transporting layer is preferably used instead of the
conductive semiconductor film and, for example, triphenyldiamine
serving as a hole-transporting layer or oxadiazole serving as an
electron-transporting layer is preferably used.
[0168] Next, an island-shape semiconductor layer 207 and a
conductive semiconductor layer 206 are obtained by patterning with
the use of a known photolithography technique. Note that a mask may
be formed using a droplet discharging method or a printing method
(relief printing, lithography, copperplate printing, screen
printing, or the like) to perform etching selectively, instead of
the known photolithography technique.
[0169] Then, wirings 203, 204, and 209 are formed by selectively
discharging a composition containing a conductive material (Ag
(silver), Au (gold), Cu (copper), W (tungsten), Al (aluminum), or
the like) by a droplet discharging method. FIG. 6A shows a state in
which the composition containing a conductive material is
discharged from an ink-jet head 208. Note that the wirings 203,
204, and 209 are not limited to be formed by a droplet discharging
method and, for example, the wirings may be formed by forming a
metal film with the use of a sputtering method, forming a mask, and
performing etching selectively.
[0170] Subsequently, the conductive semiconductor layer and an
upper portion of the semiconductor layer are etched with the use of
the wirings 203, 204, and 209 as each a mask to expose part of the
semiconductor layer. The exposed portion of the semiconductor layer
is a portion serving as a channel-forming region of a TFT.
[0171] Next, an interlayer insulating film 211 including a
protective film is formed to prevent the channel-forming region
from being contaminated with impurities. As for the protective
film, silicon nitride obtained by a sputtering method or a PCVD
method or a material containing silicon nitride oxide as its main
component is used. Hydrogenation treatment is performed in this
embodiment mode after forming the protective film. In addition, as
for the interlayer insulating film, a resin material such as epoxy
resin, acrylic resin, phenol resin, novolac resin, melamine resin,
or urethane resin is used. Moreover, an organic material such as
benzocyclobutene, parylene, fluorinated-arylene-ether, or polyimide
having transmissivity; a compound material made by polymerization
of a siloxane-based polymer or the like; a composition material
containing a water-soluble homopolymer and a water-soluble
copolymer; or the like can be used.
[0172] Then, a plurality of first openings 210 is formed by
irradiating the interlayer insulating film 211 including the
protective film with ultrashort pulsed laser light. In addition, in
order to prevent the channel-forming region from being irradiated
with laser light, a plurality of second openings 212 is also formed
by irradiating the backside of the substrate as well with
ultrashort pulsed laser light. FIG. 6B shows a cross-sectional view
in which the second openings 212 are formed by ultrashort pulsed
laser light that passes through an optical system 205.
[0173] When the pulsed width of the laser light is 10.sup.-4
seconds to 10.sup.-2 seconds, the laser light is not absorbed by
the interlayer insulating film 211 including the protective film.
However, when multiphoton absorption occurs by irradiating the
interlayer insulating film 211 including the protective film with
laser light the pulse width of which is extremely short
(picoseconds or femtoseconds), the laser light can be absorbed by
the interlayer insulating film 211 including the protective
film.
[0174] Note that forming an opening by using laser light is
explained in detail in Embodiment Mode 1; therefore, only brief
explanation is given here.
[0175] In this embodiment mode, the first insulating film 202
between the second opening 212 and the semiconductor layer 207
serves as a gate insulating film. Therefore, the film thickness of
the gate insulating film can be determined arbitrarily by the
formation of the second opening 212.
[0176] Subsequently, a composition containing conductive particles
is discharged with the use of a droplet discharging method to fill
each opening with the conductive particles so as to overlap with a
plurality of the penetrating first openings and second openings.
Then, the conductive particles are fused and aggregated to have a
crystal of approximately 100 nm when baking is performed; thus, a
gate electrode, gate wirings 214 and 215, and a connection wiring
213 are formed (see FIG. 6C). In this embodiment mode, the gate
electrode and gate wirings disposed in different layers can be
formed simultaneously and with the same material.
[0177] A channel etch TFT is completed at this stage. A significant
feature of this embodiment mode is the process order in which the
gate electrode is formed after forming the interlayer insulating
film.
[0178] FIG. 6D shows one example of a top view of a TFT at the
stage of FIG. 6C. In FIG. 6D, a cross section taken along a broken
line A-B corresponds to a cross-sectional view of FIG. 6C. Note
that corresponding portions are denoted by the same reference
numerals.
[0179] FIG. 6D shows a double-gate TFT having two channel-forming
regions. The gate wirings 214 and 215 are electrically connected
through a third opening 216 formed in a Z direction (a direction
perpendicular to the substrate) and the second opening 212 formed
in a Y direction. Note that the third opening 216 is formed using
laser light in the same manner as the first opening or the second
opening.
[0180] In addition, the second opening 212 and the third opening
216 are connected in the interlayer insulating film. Moreover, the
third opening 216 differs from the first openings 210 in depth.
Further, the connection wiring 213 is electrically connected to a
wiring 209 through the first openings 210.
[0181] In addition, in this embodiment mode, the formation order of
the first opening and the second opening is not particularly
limited and the second opening may be formed first. Moreover, the
third opening may be formed by continuously moving a focal position
of laser light in forming the second opening.
[0182] In addition, an active matrix liquid crystal display device
can be manufactured with the use of the connection wiring 213 as a
pixel electrode. Moreover, an active matrix light-emitting display
device can also be manufactured by forming a first electrode
overlapping the connection wiring 213 and a partition covering a
first end and stacking a layer containing an organic compound and a
second electrode over the first electrode.
[0183] According to this embodiment mode, since a gate electrode is
formed subsequently, a semiconductor layer 207 can be formed over a
flat insulating surface; thus, an opening for forming the gate
electrode can be formed without causing damage to the semiconductor
layer. Therefore, the semiconductor layer can be formed by a
coating method, which is effective in using an organic material for
the semiconductor layer.
[0184] In addition, according to this embodiment mode, since the
opening is formed by laser light, the comparatively low number of
manufacturing processes of a TFT can be realized.
[0185] In addition, this embodiment mode can be arbitrarily
combined with Embodiment Mode 1, Embodiment Mode 2, Embodiment Mode
3, or Embodiment Mode 4.
Embodiment Mode 6
[0186] In this embodiment mode, an example of forming a TFT
different from that of Embodiment Mode 5 is shown with reference to
FIGS. 7A to 7D.
[0187] First, a base insulating film 301 is formed over a substrate
300 having an insulating surface. As for the substrate 300 having
an insulating surface, a light-transmitting substrate, for example,
a glass substrate, a crystalline glass substrate, or a plastic
substrate can be used. When an opening is formed without laser
light passing through the substrate in the following process, a
semiconductor substrate, a metal substrate, or the like can be
used.
[0188] As for the base insulating film 301, an insulating film such
as a silicon oxide film, a silicon nitride film, or a silicon
oxynitride (SiO.sub.xN.sub.y) film is used.
[0189] Next, a semiconductor layer is formed over the base
insulating film 301. The semiconductor layer is formed by
depositing a semiconductor film having an amorphous structure by a
known means (a sputtering method, an LPCVD method, a plasma CVD
method, or the like), then forming a resist film over a crystalline
semiconductor film obtained by performing known crystallization
treatment (a laser crystallization method, a thermal
crystallization method, a thermal crystallization method using a
catalyst such as nickel or the like), and then pattering it into a
desired shape with the use of a first resist mask which is exposed
by scanning laser light. This semiconductor layer is formed to have
a thickness of 25 nm to 80 nm (preferably, 30 nm to 70 mm). A
material of the crystalline semiconductor film is not limited;
however, silicon or a silicon germanium (SiGe) alloy is preferably
used to form the crystalline semiconductor film.
[0190] Then, a gate insulating film 303 covering the semiconductor
layer is formed after removing the first resist mask. The gate
insulating film 303 is formed to have a thickness of 1 nm to 200 nm
with the use of a plasma CVD method, a sputtering method, or a
thermal oxidation method. As for the gate insulating film 303, a
film formed of an insulating film such as a silicon oxide film, a
silicon nitride film, or a silicon oxynitride film is formed.
[0191] Subsequently, a second resist mask to which light exposure
is performed by scanning laser light is formed after forming a
resist film over the gate insulating film 303. As for the second
resist mask, an impurity element imparting p-type or n-type
conductivity is selectively added to the semiconductor layer by
using an ion doping method or an ion implantation method.
Accordingly, regions where the impurity element is added serve as
impurity regions 304, 306, and 307. In addition, a region 302
covered with the second resist mask where the impurity element is
not added serves as a channel-forming region of a TFT.
[0192] Thereafter, the second resist mask is removed and the
impurity element added to the semiconductor layer is activated and
hydrogenated.
[0193] Next, as shown in FIG. 7A, an interlayer insulating film 319
having planarity is formed. As for the interlayer insulating film
319, a light-transmitting inorganic material (silicon oxide,
silicon nitride, silicon oxynitride, or the like), a photosensitive
or non-photosensitive organic material (polyimide, acrylic,
polyamide, polyimide amide, resist, or benzocyclobutene), a stack
of these materials, or the like is used. Moreover, as for another
light-transmitting film used for the interlayer insulating film
319, an insulating film formed of an SiO.sub.x film containing an
alkyl group, obtained by a coating method, for example, an
insulating film formed using silica glass, an alkyl siloxane
polymer, an alkyl silsesquioxane polymer, a hydrogenated
silsesquioxane polymer, a hydrogenated alkyl silsesquioxane
polymer, or the like can be used. As one example of a
siloxane-based polymer, a coating material for an insulating film
such as #PSB-K1 and #PSB-K31 manufactured by Toray Industries,
Inc., and a coating material for an insulating film such as
#ZRS-5PH manufactured by Catalysts & Chemicals Industries Co.,
Ltd. can be given.
[0194] Then, a plurality of first openings 309 are formed in the
interlayer insulating film 319 and the gate insulating film 303
with the use of laser light. The plurality of first openings 309 is
formed to reach the impurity regions 304 and 307. In addition, a
plurality of second openings 310 and 311 is formed in the
interlayer insulating film 319 with the use of laser light. The
plurality of second openings 310 and 311 is formed so as to overlap
with the position of the regions 302 where the impurity element is
not added. FIG. 7B shows a cross-sectional view where a focal
position of ultrashort pulsed laser light is moved after forming
the second opening 310 to form the first opening 309 by the
ultrashort pulsed laser light that passes through an optical system
305.
[0195] When the pulsed width of the laser light is 10.sup.-4
seconds to 10.sup.-2 seconds, the laser light is not absorbed by
the interlayer insulating film 319 including the protective film.
However, when multiphoton absorption occurs by irradiating the
interlayer insulating film 319 including the protective film with
laser light the pulse width of which is extremely short
(picoseconds or femtoseconds), the laser light can be absorbed by
the interlayer insulating film 319 including the protective
film.
[0196] Note that forming an opening by using laser light is
explained in detail in Embodiment Mode 1; therefore, only brief
explanation is given here.
[0197] Subsequently, a composition containing conductive particles
of 3 nm to 7 nm is discharged with the use of a droplet discharging
method to fill each opening with the conductive particles so as to
overlap with a plurality of the penetrating first openings and
second openings. Then, the conductive particles are fused and
aggregated to have a crystal of approximately 100 nm when baking is
performed; thus, gate electrodes 313 and 314, and source or drain
electrodes 312 and 315 are formed (see FIG. 7C). In this embodiment
mode, a gate electrode and a source electrode disposed in different
layers can be formed with the same material. FIG. 7C shows a state
in which a composition containing a conductive material is
discharged from the ink-jet head 308.
[0198] A top gate TFT is completed at this stage. FIG. 7C shows a
double gate TFT having two channel-forming regions. A significant
feature of this embodiment mode is process order in which the gate
electrode is formed after forming the interlayer insulating
film.
[0199] FIG. 7D shows one example of a TFT taken along in a
different cross section from FIG. 7C. In FIG. 7C, a cross-sectional
view taken along in a cross section including a broken line C-D
corresponds to FIG. 7D. Note that corresponding portions are
denoted by the same reference numerals.
[0200] As shown in FIG. 7D, the second opening 310 is extended
inside the interlayer insulating film 319, and the bottom of the
second opening 310 is in contact with the gate insulating film
303.
[0201] In addition, although not shown here, the gate electrodes
313 and 314 are in one wiring over the interlayer insulating film
319.
[0202] In addition, an active matrix liquid crystal display device
can be manufactured with the use of the TFT shown in this
embodiment mode as a switching element.
[0203] Hereinafter, a method for manufacturing a liquid crystal
display device with the use of the TFT shown in this embodiment
mode as a switching element is shown.
[0204] An insulating film 316 is formed after forming the source or
drain electrode 315 (FIG. 8). Then, a contact hole is formed in the
insulating film 316 to form a pixel electrode 317 with ITO or the
like. In addition, a terminal electrode is formed with ITO or the
like over the insulating film 316.
[0205] Next, an alignment film 320 is formed so as to cover the
pixel electrode 317. Note that the alignment film 320 is preferably
formed using a droplet discharging method, a screen printing
method, or an offset printing method. Thereafter, rubbing treatment
is performed to the surface of the alignment film 320.
[0206] In addition, an opposite substrate 323 is provided with an
opposite electrode 324 formed with a transparent electrode and an
alignment film 322 thereover. A sealant (not shown) with a closed
pattern is then formed by a droplet discharge method so as to
surround a region overlapped with a pixel portion. Here, an example
of drawing a sealant with a closed pattern is shown in order to
drop a liquid crystal. A dip coating method (pumping up method) by
which a liquid crystal is injected by using capillary phenomenon
may be used after providing a seal pattern having an opening and
attaching the TFT substrate and an opposite substrate.
[0207] Then, a liquid crystal is dropped under reduced pressure so
as to prevent bubbles from entering, and the both substrates are
attached together. A liquid crystal is dropped once or several
times in the closed-loop seal pattern. A twisted nematic (TN) mode
is mostly used as an alignment mode of a liquid crystal. In this TN
mode, the alignment direction of liquid crystal molecules is
twisted at 90.degree. according to the polarization of light from
its entrance to the exit. In the case of manufacturing a liquid
crystal display device of TN mode, the substrates are attached
together so that the rubbing directions are crossed each other.
[0208] Note that the space between the pair of substrates may be
maintained by spraying a spherical spacer, forming a columnar
spacer comprising resin, or mixing a filler into the sealant. The
above columnar spacer is formed of an organic resin material mainly
containing at least one material of acrylic, polyimide, polyimide
amide, and epoxy; any one material of silicon oxide, silicon
nitride, and silicon oxynitride; or an inorganic material composed
of a film stack of these materials.
[0209] Subsequently, an unnecessary substrate is divided. In the
case of obtaining a plurality of panels from one substrate, each
panel is separated off. In the case of obtaining one panel from one
substrate, the separation step can be skipped by attaching an
opposite substrate which is cut in advance.
[0210] Then, an FPC is attached to the terminal electrode with an
anisotropic conductive layer therebetween by a known method. A
liquid crystal module is completed according to the foregoing
processes (FIG. 8). In addition, an optical film such as a color
filter is attached, if necessary. In the case of a transmissive
liquid crystal display device, polarization plates are respectively
attached to both an active matrix substrate and an opposite
substrate.
[0211] In addition, an active matrix light-emitting device can be
manufactured with the use of the TFT shown in this embodiment
mode.
[0212] Hereinafter, a method for manufacturing an active matrix
light-emitting display device with the use of the TFT shown in this
embodiment mode is shown. Herein, an example where the TFT is an
n-channel TFT is shown.
[0213] An insulating film 316 is formed after forming a source or
drain electrode 315. Then, a contact hole is formed in the
insulating film 316 to form a first electrode 318.
[0214] It is preferable that the first electrode 318 serves as a
cathode. In the case of passing light through the first electrode
318, the first electrode 318 is formed by forming a predetermined
pattern made from a composition containing indium tin oxide (ITO),
indium tin oxide containing silicon oxide (ITSO), zinc oxide (ZnO),
tin oxide (SnO.sub.2), or the like. In addition, in the case of
reflecting light by the first electrode 318, the first electrode
318 is formed by forming a predetermined pattern made from a
composition containing metal particles as its main component such
as Ag (silver), Au (gold), Cu (copper), W (tungsten), or Al
(aluminum).
[0215] Next, a partition 331 for covering the periphery of the
first electrode 318 is formed. The partition 331 (also referred to
as a bank) is formed using a material containing silicon, an
organic material, and a compound material. Further, a porous film
can also be used for the partition 331. The partition 331 is
preferably formed by a photosensitive or a non-photosensitive
material such as acrylic or polyimide, because the partition 331 is
formed to have a curved edge portion having a radius of curvature
varying continuously, and an upper thin film of the partition 331
can be formed without step cut.
[0216] Then, a layer serving as an electroluminescent layer, that
is, a layer containing an organic compound 330 is formed. The layer
containing an organic compound 330 has a layered structure in which
each layer is formed by a vapor deposition method or a coating
method. For example, an electron-transporting layer
(electron-injecting layer), a light-emitting layer, a
hole-transporting layer, and a hole-injecting layer are
sequentially stacked over a cathode.
[0217] Before forming the layer containing an organic compound 330,
plasma treatment in the presence of oxygen or heat treatment in
vacuum atmosphere is preferably performed. In the case of using a
vapor deposition method, an organic compound is vaporized by
resistance heating in advance, and scattered toward a substrate by
opening a shutter in depositing the organic compound. The vaporized
organic compound is scattered upward and deposited over a substrate
through an opening portion provided to a metal mask. In order to
obtain full color display, alignment of a mask is preferably
performed per emission color (R, G, and B).
[0218] Alternatively, full color display can be obtained by using a
material exhibiting a monochromatic emission as the layer
containing an organic compound 330, and combining a color filter or
color conversion layer without being coated separately.
[0219] Subsequently, a second electrode 332 is formed. The second
electrode 332 serving as an anode of the light-emitting element is
formed using a transparent conductive film, which can transmit a
light, for example, by ITO, ITSO, or mixture of indium oxide mixed
with zinc oxide (ZnO). The light-emitting element has the structure
in which the layer containing an organic compound 330 is interposed
between the first electrode and the second electrode. Note that a
material for the first electrode and the second electrode should be
selected in consideration of a work function. Either the first
electrode or the second electrode is capable of being an anode or a
cathode according to a pixel structure.
[0220] In addition, a protective layer for protecting the second
electrode 332 may be formed.
[0221] Next, a sealing substrate 334 is attached by a sealant (not
shown) to seal the light-emitting element. Note that the region
surrounded by the sealant is filled with a transparent filler 333.
The filler 333 is not particularly limited. Any material can be
used as long as it a light-transmitting material, and typically,
ultraviolet curable or thermosetting epoxy resin is used.
[0222] Lastly, the FPC is attached to the terminal electrode by an
anisotropic conductive film in accordance with a known method.
[0223] According to the foregoing processes, an active matrix
light-emitting device as shown in FIG. 9 can be manufactured.
[0224] In addition, this embodiment mode can be arbitrarily
combined with Embodiment Mode 1, Embodiment Mode 2, Embodiment Mode
3, Embodiment Mode 4, or Embodiment Mode 5.
[0225] Embodiments of the present invention composed of the
foregoing aspects are described in further detail below.
Embodiment 1
[0226] In this embodiment, a step of forming a multilayer wiring
over a semiconductor substrate will be explained with reference to
FIGS. 12A to 12D.
[0227] First, a semiconductor substrate 500 made of single crystal
silicon is prepared (FIG. 12A). The semiconductor substrate 500 is
a single crystal silicon substrate or a compound semiconductor
substrate, and typically, an N-type or a P-type single crystal
silicon substrate, a GaAs substrate, an InP substrate, a GaN
substrate, an SiC substrate, a sapphire substrate, or a ZnSe
substrate.
[0228] Next, an n-well is selectively formed in a first
element-forming region in a main surface (also referred to as an
element-forming surface or a circuit-forming surface) of the
silicon substrate and a p-well is selectively formed in a second
element-forming region in the same surface, respectively.
[0229] Then, field oxide films 503, 504, and 505 to be
element-isolating regions for partitioning the first
element-forming region and the second element-forming region are
formed. The field oxide films 503, 504, and 505 are thick thermal
oxide films and may be formed by a known LOCOS method. Note that
the element-isolating method is not limited to the LOCOS method.
For example, the element-isolating region may have a trench
structure by using a trench-isolating method, or the LOCOS
structure and the trench structure may be combined.
[0230] Subsequently, a gate insulating film is formed by, for
example, thermally oxidizing the surface of the silicon substrate.
The gate insulating film may also be formed using a CVD method. A
silicon oxynitride film, a silicon oxide film, a silicon nitride
film, or a stack thereof may be used. For example, a film stack of
a silicon oxide film with a thickness of 5 nm which is obtained by
thermal oxidation and a silicon oxynitride film with a thickness of
10 nm to 15 nm which is obtained by a CVD method is formed.
[0231] Next, a film stack of a polysilicon layer and a silicide
layer are formed over the entire surface, and the film stack is
patterned by a lithography technique and a dry etching technique so
as to form a gate electrode 506 having a polycide structure over
the gate insulating film. The polysilicon layer may be doped with
phosphorus (P) at a concentration of approximately
10.sup.21/cm.sup.3 in advance in order to reduce the resistance.
Alternatively, high concentration n-type impurities may be diffused
after forming the polysilicon layer. Further, the silicide layer is
preferably formed of a material such as molybdenum silicide
(MoSi.sub.x), tungsten silicide (WSi.sub.x), tantalum silicide
(TaSi.sub.x), or titanium silicide (TiSi.sub.x) using a known
method.
[0232] Then, the gate insulating film is selectively removed.
Accordingly, a gate insulating film 508 having a width of the gate
electrode is formed.
[0233] Subsequently, sidewalls 510 to 513 are formed on the side
walls of the gate electrode. For example, an insulating material
layer formed of silicon oxide may be deposited over the entire
surface by a CVD method and the insulating material layer is
preferably etched back to form the sidewalls.
[0234] Next, an ion implantation is performed into the exposed
silicon substrate to form a source region and a drain region. Since
this is the case of manufacturing a CMOS, the first element-forming
region for forming a p-channel FET is coated with a resist
material, and arsenic (As) or phosphorus (P) which is an n-type
impurity is injected into the silicon substrate to form a source
region 514 and a drain region 515. At the same time,
low-concentration impurity regions 518 and 519 added with an n-type
impurity by passing through the sidewalls are formed. In addition,
the second element-forming region for forming an n-channel FET is
coated with a resist material, and boron (B) which is a p-type
impurity is injected into the silicon substrate to form a source
region 516 and a drain region 517. At the same time,
low-concentration impurity regions 520 and 521 added with a p-type
impurity by passing through the sidewalls are formed.
[0235] Then, activation treatment is performed using a GRTA method,
an LRTA method, or the like in order to activate the ion-implanted
impurities and to reduce crystal defects in the silicon substrate,
which is generated by the ion implantation (see FIG. 12A).
[0236] Subsequently, as shown in FIG. 12B, a first interlayer
insulating film 545 is formed. The first interlayer insulating film
545 is formed in a thickness of 100 nm to 2000 nm with a silicon
oxide film, a silicon oxynitride film, or the like by a plasma CVD
method or a low-pressure CVD method. Further, an interlayer
insulating film formed of phosphosilicate glass (PSG), borosilicate
glass (BSG), or borophosphosilicate glass (PBSG) may be stacked
thereover.
[0237] Next, as shown in FIG. 12B, penetrating openings 541 to 544
are formed by irradiation of laser light emitted from an ultrashort
pulsed laser. This is a method for forming an opening according to
the present invention shown in Embodiment Mode 1.
[0238] Then, as shown in FIG. 12C, conductive films 551 to 554 are
formed by discharging and baking a composition containing
conductive particles to the openings by a droplet discharging
method. According to the present invention, a depression is not
generated in portions overlapping with the openings; thus, top
surfaces of the conductive films 551 to 554 are almost in one
plane.
[0239] Thereafter, a second interlayer insulating film 561 is
formed. Then, openings and conductive films 562 to 565 are formed
in the same manner, and multilayer wirings can be formed as shown
in FIG. 12D. Since the top surfaces of the conductive films 551 to
554 are almost in one plane, the depth of each of the openings
penetrating through the second interlayer insulating film 561 can
be kept uniform.
[0240] In addition, an SOI substrate is used as the semiconductor
substrate 500 and treatment in which a circuit having a MOS
transistor can be peeled at an interface with an oxidized
insulating film or in the layer thereof or at an interface between
the oxidized insulating film and a silicon substrate or at an
interface between the oxidized insulating film and the circuit is
performed. Therefore, the circuit having a MOS transistor can be
peeled. In addition, a thinner film of a semiconductor device can
be obtained by attaching the peeled circuit having a MOS transistor
to a flexible substrate.
[0241] In addition, the semiconductor device shown in this
embodiment is applicable to various semiconductor devices such as a
bipolar transistor as well as a MOS transistor. Moreover, the
semiconductor device is also applicable to an electric circuit such
as a memory circuit or a logic circuit.
[0242] An IC chip in which an FET manufactured according to this
embodiment is integrated can be used as a thin film integrated
circuit or a non-contact thin film integrated circuit device (also
referred to as a wireless IC tag or RFID (Radio Frequency
Identification)).
[0243] FIG. 13 shows an example of an ID card in which an IC chip
1516 according to the present invention is attached to a card-like
substrate 1518 provided with a conductive layer 1517 serving as an
antenna. The conductive layer 1517 serving as an antenna can also
be formed by a droplet discharging method. In addition, a contact
hole with a connection electrode connected to the conductive layer
1517 serving as an antenna may be formed using a technique for
forming an opening by using laser light. Thus, the IC chip 1516
according to the present invention is small, thin, and lightweight,
so that diverse uses can be realized and the design of an article
is not spoiled even when the IC chip is attached to the
article.
[0244] Note that the IC chip 1516 according to the present
invention is not limited to the case of being attached to the
card-like substrate 1518, and can be attached to an article having
a curved surface or various shapes. For example, the IC chips can
be used in bill, money, coin, securities, bearer bonds,
certificates (such as a driver's license, or a resident's card,
packing cases (such as a wrapper or a bottle), memory media (such
as a DVD, a video tape), vehicles (such as a bicycle), belongings
(such as a bag, or glasses), food, clothing, commodities, and the
like.
[0245] In addition, this embodiment can be arbitrarily combined
with Embodiment Mode 1, Embodiment Mode 2, Embodiment Mode 3,
Embodiment Mode 4, Embodiment Mode 5, or Embodiment Mode 6.
Embodiment 2
[0246] In this embodiment, a module having the display panel shown
in the above Embodiment Mode 5 or Embodiment Mode 6 will be
explained with reference to FIG. 14. FIG. 14 shows a module
including a display panel 9501 and a circuit board 9502. For
example, a control circuit 9504, a signal division circuit 9505,
and the like are mounted on the circuit board 9502. In addition,
the display panel 9501 is connected to the circuit board 9502
through a connecting wire 9503. As for the display panel 9501, the
liquid crystal panel or the light-emitting display panel shown in
Embodiment Mode 5 or Embodiment Mode 6 may be arbitrarily used.
[0247] The display panel 9501 has a pixel portion 9506 where a
light-emitting element is provided in each pixel, a scanning-line
driver circuit 9507, and a signal-line driver circuit 9508 that
supplies a video signal to a selected pixel. The pixel portion 9506
has the same structure as that shown in Embodiment Mode 5 or
Embodiment Mode 6. As for the scanning-line driver circuit 9507 and
the signal-line driver circuit 9508, IC chips are mounted on the
substrate by a known mounting method such as a method using an
anisotropic conductive adhesive or an anisotropic conductive film,
a COG method, a wire bonding method, reflow treatment using a
solder bump, or the like.
[0248] This embodiment allows a display module to be formed at low
cost.
[0249] In addition, this embodiment can be arbitrarily combined
with Embodiment Mode 1, Embodiment Mode 2, Embodiment Mode 3,
Embodiment Mode 4, Embodiment Mode 5, Embodiment Mode 6, or
Embodiment 1.
Embodiment 3
[0250] Although a liquid crystal display module and a
light-emitting display module are shown as an example of the
display module in the above embodiment, the present invention is
not limited thereto. The present invention can be appropriately
applied in forming an opening and wiring of a display module such
as a DMD (Digital Micro mirror Device), a PDP (Plasma Display
Panel), an FED (Field Emission Display), an electrophoretic display
device (electronic paper), or an electro deposition image display
device.
[0251] In addition, this embodiment can be arbitrarily combined
with Embodiment Mode 1, Embodiment Mode 2, Embodiment Mode 3,
Embodiment Mode 4, Embodiment Mode 5, or Embodiment Mode 6.
Embodiment 4
[0252] The semiconductor device shown in the above embodiment modes
and embodiments may be applied to electronic apparatuses such as a
television set (also simply referred to as a television or a
television receiver). Here, a specific example of a television set
will be explained with reference to FIGS. 15A and 15B.
[0253] FIG. 15A shows a block diagram of a television set, while
FIG. 15B shows a perspective view of a television set. A liquid
crystal television set and an EL television set can be completed by
using the liquid crystal module and the EL module that are shown in
the above embodiments.
[0254] FIG. 15A is a block diagram showing main components of a
television set. A tuner 9511 receives a video signal and an audio
signal. The video signal is processed by an image detection circuit
9512, a video signal processing circuit 9513 that converts a signal
outputted from the image detection circuit into a color signal
corresponding to each of red, green, and blue, and a control
circuit 9514 that converts the video signal in accordance with
input specifications of a driver IC. The control circuit 9514
outputs a signal to a scanning-line driver circuit 9516 and a
signal-line driver circuit 9517 of a display panel 9515. In the
case of digital driving, a signal division circuit 9518 may be
provided on the signal line side, so that an inputted digital
signal is divided into m signals to be supplied.
[0255] Among signals received by the tuner 9511, an audio signal is
transmitted to a sound detection circuit 9521, and an output
thereof is supplied to a speaker 9523 through an audio signal
processing circuit 9522. A control circuit 9524 receives control
information of a receiving station (received frequency) and a sound
volume from an input portion 9525, and transmits signals to the
tuner 9511 and the audio signal processing circuit 9522.
[0256] As shown in FIG. 15B, a television set can be completed by
incorporating a module in a housing 9531. A display screen 9532 is
formed using a module typified by a liquid crystal module and an EL
module. In addition, the television set also includes a speaker
9533, operating switches 9534, and the like.
[0257] Since this television set includes the display panel 9515,
cost reduction thereof can be achieved. In addition, the television
set with high definition can be provided.
[0258] The application of the present invention is not limited to
the television receiver, and various applications are possible,
such as a monitor for a personal computer as well as, in
particular, a display medium with a large area such as an
information display panel at stations or airports, and an
advertisement display panel on the street.
[0259] In addition, this embodiment can be arbitrarily combined
with Embodiment Mode 1, Embodiment Mode 2, Embodiment Mode 3,
Embodiment Mode 4, Embodiment Mode 5, or Embodiment Mode 6.
Embodiment 5
[0260] A semiconductor device and an electronic device according to
the present invention include a camera such as a video camera or a
digital camera, a goggle type display (head mounted display), a
navigation system, an audio player (a car audio, an audio
component, and the like), a personal computer, a game machine, a
portable information terminal (a mobile computer, a cellular phone,
a portable game machine, an electronic book, and the like), an
image reproducing device provided with a recording medium
(specifically a device capable of reproducing the content of a
recording medium such as a Digital Versatile Disc (DVD) and that
has a display device capable of displaying the image), and the
like. Specific examples of the electronic devices are shown in
FIGS. 16A to 16E.
[0261] FIG. 16A is a digital camera, which includes a main body
2101, a display portion 2102, an imaging portion, operation keys
2104, a shutter 2106, and the like. Note that FIG. 16A is viewed
from the side of the display portion 2102 and the imaging portion
is not shown. According to the present invention, the digital
camera can be obtained through a process where the manufacturing
cost is reduced.
[0262] FIG. 16B is a personal computer, which includes a main body
2201, a housing 2202, a display portion 2203, a keyboard 2204, an
external connection port 2205, a pointing mouse 2206, and the like.
According to the present invention, the personal computer can be
obtained through a process where the manufacturing cost is
reduced.
[0263] FIG. 16C is a mobile image reproducing device provided with
a recording medium (specifically, a DVD player), which includes a
main body 2401, a housing 2402, a display portion A 2403, a display
portion B 2404, a recording medium (DVD or the like) reading
portion 2405, operation keys 2406, a speaker portion 2407, and the
like. The display portion A 2403 is used mainly for displaying
image information, whereas the display portion B 2404 is used
mainly for displaying text information. Note that the image
reproducing device provided with a recording medium also includes a
home-use game machine or the like. According to the present
invention, the image reproducing device can be obtained through a
process where the manufacturing cost is reduced.
[0264] In addition, FIG. 16D is a perspective view of a portable
information terminal, and FIG. 16E is a perspective view showing a
state of using it as a folding cellular phone. In FIG. 16D, users
operate operation keys 2706a with their right fingers and operate
operation keys 2706b with their left fingers when they are used as
a keyboard. According to the present invention, the portable
information terminal can be obtained through a process where a
manufacturing cost is reduced.
[0265] As shown in FIG. 16E, in folding a cellular phone, users
have a main body 2701 and a housing 2702 in one hand and use an
audio input portion 2704, an audio output portion 2705, operation
keys 2706c, an antenna 2708, and the like.
[0266] The portable information terminals shown in FIGS. 16D and
16E each includes a high-definition display portion 2703a which
horizontally displays images and characters mainly and a display
portion 2703b which vertically displays.
[0267] As described above, various electronic devices can be
completed by employing a manufacturing method or a structure
according to the present invention, that is, any one of Embodiment
Modes 1, Embodiment Mode 2, Embodiment Mode 3, Embodiment Mode 4,
Embodiment Mode 5, Embodiment Mode 6, and Embodiments 1 to 4.
Embodiment 6
[0268] According to the present invention, a semiconductor device
serving as a wireless chip (also called a wireless processor, a
wireless memory, or a wireless tag) can be manufactured.
[0269] An example of mounting a chip obtained by cutting a
semiconductor substrate on a card having an antenna is shown in
Embodiment 1; however, a wireless chip can also be formed using a
TFT.
[0270] A structure of a wireless chip according to the present
invention will be explained with reference to FIG. 17. A wireless
chip is constituted by a thin film integrated circuit 9303 and an
antenna 9304 connected thereto. The thin film integrated circuit
9303 and the antenna 9304 are sandwiched between cover materials
9301 and 9302. The thin film integrated circuit 9303 may be
attached to the cover materials with an adhesive. In FIG. 17, one
surface of the thin film integrated circuit 9303 is attached to the
cover material 9301 with an adhesive 9305.
[0271] The thin film integrated circuit 9303 is formed using a TFT
shown in Embodiment Mode 5 or Embodiment Mode 6, then peeled off by
a known peeling step and attached to a cover material. In addition,
the semiconductor element used for the thin film integrated circuit
9303 is not limited thereto, and in addition to the TFT, a memory
element, a diode, a photoelectric converter, a resistor, a coil, a
capacitor, an inductor, or the like may be used.
[0272] As shown in FIG. 17, an interlayer insulating film 9311 is
formed over the TFT of the thin film integrated circuit 9303, and
the antenna 9304 is connected to the TFT through the interlayer
insulating film 9311. In addition, a barrier film 9312 made of
silicon nitride or the like is formed over the interlayer
insulating film 9311 and the antenna 9304.
[0273] The antenna 9304 is formed by discharging a droplet
containing a conductor such as gold, silver and copper by a droplet
discharging method, then baking and drying it. When the antenna is
formed by a droplet discharging method, reduction in the number of
steps can be realized, leading to cost reduction.
[0274] Each of the cover materials 9301 and 9302 preferably uses a
film (made of polypropylene, polyester, vinyl, polyvinyl fluoride,
vinyl chloride, or the like), paper of a fibrous material, a film
where a base film (polyester, polyamide, an inorganic vapor
deposition film, papers, or the like), and an adhesive synthetic
resin film (an acrylic based synthetic resin, an epoxy based
synthetic resin, or the like) are stacked, or the like. The film is
obtained by performing sealing treatment to the subject by
thermocompression. In the sealing treatment, an adhesive layer
formed on the upper most surface of the film or a layer (not an
adhesive layer) formed on the outermost layer is melted by heat
treatment to adhere by applying pressure.
[0275] When the cover materials use a flammable pollution-free
material such as paper, fiber and carbon graphite, the used
wireless chip can be burned or cut out. In addition, the wireless
chip using such a material is pollution free because it does not
generate poison gas even if being burned.
[0276] Although the wireless chip is attached to the cover material
9301 with the adhesive 9305 in FIG. 17, the wireless chip may be
attached to the object instead of the cover material 9301.
[0277] The wireless chip 9210 may be mounted on various objects and
one example is shown in FIG. 18A to 18, for example, such as bills,
coins, securities, bearer bonds, certificates (licenses, resident
cards and the like, see FIG. 18A), containers for wrapping objects
(wrapping papers, bottles and the like, see FIG. 18C), recording
media (DVDs, video tapes and the like, see FIG. 18B), vehicles
bicycles and the like, see FIG. 18D), belongings (bags, glasses and
the like), foods, plants, animals, human body, clothes, living
ware, and electronic apparatuses, or shipping tags of objects (see
FIGS. 18E and 18F). The electronic apparatuses include liquid
crystal display devices, EL display devices, television sets (also
simply called televisions or television receivers), cellular
phones, and the like.
[0278] A wireless chip is attached to the surface of the object or
incorporated in the object to be fixed. For example, a wireless
chip is preferably incorporated in a paper of a book, or an organic
resin of a package. When a wireless chip is incorporated in bills,
coins, securities, bearer bonds, certificates, and the like,
forgery thereof can be prevented. In addition, when a wireless chip
is incorporated in containers for wrapping objects, recording
media, belongings, foods, clothes, living ware, electronic
apparatuses, and the like, test systems, rental systems, and the
like can be performed more efficiently. A wireless chip according
to the present invention is obtained in such a manner that a thin
film integrated circuit formed over a substrate is peeled off by a
known peeling step and then attached to a cover material;
therefore, the wireless chip can be reduced in size, thickness and
weight and can be mounted on an object while keeping the attractive
design. In addition, since such a wireless chip has flexibility,
the wireless chip can be attached to an object having a curved
surface, such as bottles and pipes.
[0279] When a wireless chip according to the present invention is
applied to product management and distribution system, high
performance system can be achieved. For example, when information
stored in a wireless chip mounted on a shipping tag is read by a
reader/writer provided beside a conveyor belt, information such as
distribution process and delivery address is read to easily inspect
and distribute the object.
[0280] In addition, this embodiment can be arbitrarily combined
with Embodiment Mode 1, Embodiment Mode 2, Embodiment Mode 3,
Embodiment Mode 4, Embodiment Mode 5, Embodiment Mode 6, or
Embodiment 1.
[0281] According to the present invention, since the number of
etching steps accompanying a photolithography method can be
reduced, the loss and effluent amount of a material solution can be
reduced. In addition, the present invention can realize a
manufacturing process with the use of a droplet discharging method
suitable for manufacturing a large-sized substrate in mass
production.
[0282] The present application is based on Japanese Patent
Application serial No. 2005-014756 filed on Jan. 21, 2005 in
Japanese Patent Office, the contents of which are hereby
incorporated by reference.
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