U.S. patent application number 11/377581 was filed with the patent office on 2006-11-16 for semiconductor device, display device and device fabricating method.
This patent application is currently assigned to THE FURUKAWA ELECTRIC CO., LTD.. Invention is credited to Takeshi Hirayama, Hisashi Koaizawa, Michio Kondo, Kenkichi Suzuki, Tsuneo Suzuki, Kiyoshi Yase.
Application Number | 20060257074 11/377581 |
Document ID | / |
Family ID | 37419194 |
Filed Date | 2006-11-16 |
United States Patent
Application |
20060257074 |
Kind Code |
A1 |
Suzuki; Tsuneo ; et
al. |
November 16, 2006 |
Semiconductor device, display device and device fabricating
method
Abstract
The invention provides a display device using a one-dimensional
substrate making layout of a substrate unnecessary and realizing a
further low cost. A display device of the invention comprises a
first fiber 80 having a silicon layer or an oxide layer, on which
an active element is formed, formed on the surface of it and a
second fiber 81 forming a combined one-dimensional substrate
together with the first fiber 80 by being combined with the first
fiber 80 and having light emitting layers formed on a plurality of
domains of it, wherein the first fiber 80 and the second fiber 81
are respectively drawn out from take-up jigs, are cut in necessary
lengths and separated into plural fibers, and these plural first or
second fibers 80 or 81 are mounted in parallel with each other on a
fixing jig and in this state, at least one-side elements of active
elements and passive elements are formed on the first or second
fibers 80 or 81.
Inventors: |
Suzuki; Tsuneo; (Tokyo,
JP) ; Hirayama; Takeshi; (Tokyo, JP) ;
Koaizawa; Hisashi; (Tokyo, JP) ; Yase; Kiyoshi;
(Ibaraki, JP) ; Suzuki; Kenkichi; (Ibaraki,
JP) ; Kondo; Michio; (Ibaraki, JP) |
Correspondence
Address: |
C. IRVIN MCCLELLAND;OBLON, SPIVAK, MCCLELLAND, MAIER & NEUSTADT, P.C.
1940 DUKE STREET
ALEXANDRIA
VA
22314
US
|
Assignee: |
THE FURUKAWA ELECTRIC CO.,
LTD.
Tokyo
JP
|
Family ID: |
37419194 |
Appl. No.: |
11/377581 |
Filed: |
March 17, 2006 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
PCT/JP04/13773 |
Sep 21, 2004 |
|
|
|
11377581 |
Mar 17, 2006 |
|
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Current U.S.
Class: |
385/49 ;
257/E29.295 |
Current CPC
Class: |
H01L 27/3244 20130101;
H01L 51/52 20130101; H01L 29/78603 20130101; H01L 51/5287 20130101;
H01L 27/1214 20130101; G02B 6/001 20130101 |
Class at
Publication: |
385/049 |
International
Class: |
G02B 6/30 20060101
G02B006/30 |
Claims
1. A semiconductor device comprising: a semiconductor layer formed
on the surface of a quartz fiber; and an active element formed on
said semiconductor layer.
2. A semiconductor device according to claim 1, wherein said
semiconductor layer is a single crystal or polycrystal silicon
layer.
3. A semiconductor device according to claim 1, wherein wiring is
formed on said quartz fiber.
4. A semiconductor device according to claim 3, wherein a metal
wire material is connected to said wiring.
5. A semiconductor device according to claim 1, wherein said active
element is a transistor.
6. A semiconductor device according to claim 5, wherein said
transistor is a MOS transistor and has an oxide film formed on said
semiconductor layer and a gate electrode formed on said oxide
film.
7. A display device comprising: a fiber made of a transparent
insulating material; an electrode film formed on said fiber; and a
light emitting layer formed on said fiber.
8. A display device according to claim 7, wherein said fiber is
formed out of one of quartz and plastic.
9. A display device according to claim 7, wherein said electrode
film is a transparent electrode film.
10. A display device according to claim 9, wherein said transparent
electrode film is formed between said light emitting layer and said
fiber.
11. A display device according to claim 7, wherein said transparent
electrode film is formed on the opposite face of said organic light
emitting layer to said fiber side.
12. A display device according to claim 7, wherein said electrode
film is connected to the opposite face of said light emitting layer
to the light output direction.
13. A display device according to claim 7, wherein said light
emitting layer is an organic electroluminescence layer.
14. A display device according to claim 7, wherein said light
emitting layer is formed in a plurality of domains.
15. A display device according to claim 7, wherein a plurality of
said fibers are arranged in parallel adjacently to each other.
16. A display device including: a first fiber on which an active
element is formed; and, a second fiber which forms a combined
one-dimensional substrate together with said first fiber by being
combined with said first fiber and light emitting layers are formed
on a plurality of domains thereof.
17. A display device according to claim 16, wherein a plurality of
said combined one-dimensional substrates form a display screen by
being arranged in parallel with each other.
18. A display device according to claim 16, which comprises: a
first protective film formed out of a transparent material at the
light outputting side of said display screen; and a second
protective film formed out of a light shielding material at the
opposite side to the light outputting side of said display
screen.
19. A display device according to claim 16, wherein a first signal
line conductor being formed in the longitudinal direction and
introducing an external image signal into said active element, and
a current source linear conductor being formed in the longitudinal
direction and supplying said light emitting layer with current are
formed on said first fiber.
20. A display device according to claim 16, wherein a current
source is connected to an end of said current source linear
conductor.
21. A display device according to claim 16, which further
comprising: a conductive pad being formed on said first fiber and
connected to said active element; and a second signal line
conductor being disposed in a direction crossing the longitudinal
direction of said first fiber and connected to a conductive
pad.
22. A display device according to claim 21, wherein a driving
circuit is connected to ends of said first signal line conductor
and said second signal line conductor.
23. A display device according to claim 22, which includes a common
electrode consisting of a transparent conductor formed on the light
outputting side of said light emitting layer.
24. A display device according to claim 7, wherein light emitting
element fibers having light emitting elements formed thereon are
arranged into the shape of a flat surface or a curved surface in
the longitudinal direction of a one-dimensional base material
composed of said fiber or a one-dimensional substrate having
electrodes formed on said one-dimensional base material, and a
driving circuit is set in the vicinity of each of said light
emitting elements.
25. A display device according to claim 24, wherein said driving
circuit is formed out of said one-dimensional base material or a
one-dimensional substrate obtained by forming a semiconductor on
said one-dimensional base material and is connected to said light
emitting element fiber corresponding to said driving circuit.
26. A display device according to claim 25, wherein the shape of a
section of said one-dimensional substrate is a rectangle or a
polygon.
27. A display device according to claim 25, wherein the maximum
projected area of said light emitting element fiber is equal to or
larger than the maximum projected area of said one-dimensional
substrate.
28. A display device according to claim 24, wherein said light
emitting element fibers having said light emitting elements formed
thereon are arranged into the shape of a flat surface or a curved
surface in the longitudinal direction of said one-dimensional base
material or a one-dimensional TCO substrate having transparent
electrodes formed on said one-dimensional base material, and said
driving circuit of each of said light emitting elements is formed
using said one-dimensional substrate.
29. A device fabricating method comprising the steps of; drawing
out a fiber having a semiconductor layer or an insulating layer
formed on the surface of it and further being covered with a
protective film from a take-up jig; removing said protective film
drawn out from said take-up jig; cutting and separating a portion,
from which said protective film has been removed, of said fiber in
necessary lengths and into plural fibers; fixing said plural fibers
on the outer surface or inner surface of an annular face; and
forming at least one-side elements of active elements and passive
elements on said fibers on said annular face.
30. A device fabricating method according to claim 29, wherein said
annular face is one of the surface of a cylinder or a polygonal
prism or the inner surface of a tube.
31. A device fabricating method according to claim 29, which
comprises a step of disposing a process head over said fiber on
said annular face, turning said annular face and successively
growing films one-dimensionally on said fibers.
32. A device fabricating method according to claim 29, which
comprises a step in which said fiber is placed in a film forming
atmosphere in a state where it is fixed on said annular face.
33. A device fabricating method according to claim 29, which
comprises a step of disposing a process head over said fiber,
turning said annular face and successively applying resist to said
fibers.
34. A device fabricating method according to claim 33, which
comprises a step of disposing a lens system of an exposure
apparatus over said fiber, turning said annular face and
successively exposing resist on said fibers.
35. A device fabricating method according to claim 29, which
comprises a step in which said fibers are immersed in a solution
together with said annular face and are wet-processed.
36. A device fabricating method comprising the steps of: drawing
out a fiber having a semiconductor layer or an insulating layer
formed on the surface of it and further being covered with a
protective film from a take-up jig; removing said protective film
drawn out from said take-up jig; cutting and separating a portion,
from which said protective film has been removed, of said fiber in
necessary lengths and into plural fibers; mounting said plural
fibers on a fixing jig at some intervals; and forming at least
one-side elements of active elements and passive elements on said
fibers fixed on said fixing jig.
Description
TECHICAL FIELD
[0001] The present invention relates to a semiconductor device, a
display device and a device fabricating method, and more
particularly to a method of fabricating a semiconductor device
forming an organic EL display device or the like and a device such
as an organic EL display device and the like.
BACKGROUND ARTS
[0002] An active matrix type flat display device being the main
current at present is a flat display comprising pixel driving
switches composed of TFT (Thin Film Transistor) and a pixel display
medium on the surface of it, and a substrate of its starting point
is a transparent glass plate of soda lime and the like. Attempts to
use a plastic film as a substrate have been performed but do not
yet succeed in being put to practical use, and the main current at
present is liquid crystal as a display medium and a-Si TFT
(Amorphous-Silicon-TFT) as an active matrix, and displays of 10''
to 20'' in diagonal size are mass-produced for PCs, monitors and
the like.
[0003] LCD (Liquid Crystal Display) as a display medium has
problems in display performance of TV dynamic images, particularly
in white, white peak, responsiveness and the like in comparison
with CRT (Cathode Ray Tube). On the contrary, organic LED (OLED:
Organic Light-Emitting-Diode) of which product development is
recently promoted is self-luminous and can realize an image quality
being more excellent in white, white peak, responsiveness and the
like than LCD.
[0004] On the other hand, in TFT also, product development of
polycrystalline Si by a low-temperature process (low temperature
p-Si) is rapidly promoted. The reason is that first, p-Si is high
in TFT performance and can have a peripheral circuit built in it
and therefore has an advantage of cost reduction. In addition to
this, since a-Si TFT is difficult to cope with drive of organic LED
from the viewpoint of a driving current density, the transition of
TFT to low-temperature p-Si including application of it to LCD is
the general trend.
[0005] Market demands in all display devices including an active
matrix type flat display device are always three points of the
enlargement in size, high definition and cost reduction of display
device. For these demands, a-Si TFT-LCD being the main current at
present has little room for improvement in performance and is in
the state that a substantial limit is TV of 40'' in diagonal length
for enlargement and display of 20'' or less for high definition and
the enlargement of glass substrate may be said to be only one means
for cost reduction.
[0006] On the other hand, low-temperature p-Si TFT-LCD is excellent
in performance of TFT itself in principle and can have a peripheral
circuit built in it but has grave problems in practice. That is to
say, there are various fundamental problems of processes being
performed at a low temperature of 500.degree. C. or lower, lack of
uniformity due to polycrystal, lithography accuracy of 1 .mu.m or
more and the like because of a glass substrate. Particularly, the
low-temperature p-Si TFT must realize a performance equivalent to
Si LSI in a peripheral circuit but is difficult to realize a high
image quality under such restrictions, and is in the state of being
applied to some of peripheral circuits of a low-definition
display.
[0007] In case that a display medium is organic LED, namely,
TFT-OLED (TFT-Organic Liquid-Emitting-Diode), the quality of
display is greatly improved in comparison with LCD from the
viewpoint of self-luminance, high-speed response, thinning and the
like. However, since a pixel driving circuit is composed of several
transistors instead of one transistor because of current drive
differently from LCD. Although there is the attempt to form a pixel
driving circuit out of a-Si TFT due to the advantage of uniformity,
a large-sized high-definition display cannot but use p-Si TFT.
[0008] However, a substrate is of glass and has fundamental
problems with respect to TFT itself as described above, and further
a large-sized glass substrate cannot but be used for cost reduction
similarly to an a-Si-TFT-LCD fabricating technology.
[0009] Organic LED is composed of an organic thin film of 5 to 8
layers, the total film thickness of it is about 100 to 500 nm, and
the thickness of each component film must be formed with accuracy
of about 1 nm. Additionally, pixels corresponding to three colors
must be formed separately over a large area. Further, since current
consumption is greatly increased to 10 to 100 mA/cm.sup.2 due to
current drive in case of OLED while current consumption is 1
.mu.A/cm.sup.2 due to voltage drive in case of LCD, wiring
resistance from a current source needs to be reduced by several
digits in comparison with wiring of LCD. It is apparent that the
more large-sized and more high-definition a display is, the more
difficult the solution of such problems in manufacture is.
[0010] These essential problems are in a fact that they are
apparently natural, that is, in a fundamental assumption of the
prior art using a two-dimensional flat plate as a substrate. That
is to say, the improvement in process accuracy is demanded
simultaneously with enlargement in size of a substrate and a
fabricating apparatus must be made more accurate at the same time
as being made large-sized. Naturally there is some limit in
mechanism and a limit appears in throughput also. In practice, an
a-Si TFT-LED fabricating apparatus coping with a substrate of
nearly 2 m square in size is made and used at present, but this is
thought to be one limit with respect to cost-performance ratio of
apparatus and production line.
[0011] The situation in p-Si TFT-LCD based on the existing a-Si
TFT-LCD fabricating apparatus and technology is entirely the same.
Additionally, p-Si TFT-LCD is in a more difficult situation that a
process similar to that of Si LSI must be realized at a low
temperature. Cost reduction by having a circuit built-in is one of
advantages of p-Si TFT-LCD, but this is realized when a
high-performance circuit is implemented. In practice, the more
large-sized a substrate is made, the more difficult it is to
realize various requirements necessary for a high-performance
device such as the quality of film, the accuracy of
photolithography, similar processes to those of Si LSI and the
like. As for this point, p-Si TFT-OLED is entirely the same and
further additionally has problems of LED structure, wiring
resistance and the like as described above.
DISCLOSURE OF THE INVENTION
Problems the Invention Attempts to Solve
[0012] Although technical problems related to the manufacture in
case of using a large-sized substrate have been pointed in the
above description, various sizes are demanded in a concrete product
development of display. Layout of substrate is not necessarily
efficiently performed but may make waste. The optimal size of a
substrate used by a manufacturer is not necessarily the optimal
size to a user.
[0013] An object of the present invention is to provide a
semiconductor device using a one-dimensional substrate, a display
device and a device fabricating method for solving these various
problems in performance and manufacture and further realizing a low
cost.
Means for Solving the Problems
[0014] A first aspect of the present invention is a semiconductor
device having a semiconductor layer formed on the surface of a
quartz fiber and an active element formed on said semiconductor
layer.
[0015] A second aspect of the present invention is a display device
being characterized by having a fiber made of a transparent
insulating material, an electrode film formed on said fiber and a
light emitting layer formed on said fiber.
[0016] A third aspect of the present invention is a display device
being provided with a first fiber which an active element is formed
on, a second fiber which forms a combined one-dimensional substrate
with said first fiber by being combined with said first fiber and a
plurality of domains of which light emitting layers are formed
on.
[0017] A fourth aspect of the present invention is a device
fabricating method being characterized by comprising a step of
drawing out a fiber the surface of which a semiconductor layer or
an insulating layer is formed on and which is covered with a
protective film from a take-up jig, a step of removing said
protective film drawn out from said take-up jig, a step of cutting
and separating a portion, from which said protective film has been
removed, of said fiber in necessary lengths and into a plurality of
fibers, a step of attaching said plurality of fibers to a fixing
jig at intervals, and a step of forming at least one-side elements
of active elements and passive elements on said fibers.
[0018] In order to achieve the above-mentioned object, the present
invention proposes a new concept of "one-dimensional substrate"
based on a quartz fiber and the like in contrast with a
conventional two-dimensional substrate and attempts to solve the
above-mentioned problems of a display device. A one-dimensional
substrate of the present invention corresponding to a conventional
SOI (Silicon On Insulator) substrate has a silicon single crystal
thin film or a silicon polycrystal thin film formed on a quartz
fiber and hereinafter is referred to as an SOI fiber.
[0019] A method of fabricating this one-dimensional substrate is a
high-temperature fabricating method of forming a silicon thin film
crystal at the same time as drawing a quartz fiber, and further can
form a high-quality oxide film for gate by thermally oxidizing the
silicon film formed. Hereinafter, this is referred to as an SOI
fiber with oxide film. By using these, since a base material is
quartz, it is possible to use processes and a process flow being
entirely the same as those of a two-dimensional SOI substrate
instead of low-temperature processes of a glass substrate and to
form various high-performance semiconductor devices.
[0020] It is an ITO fiber that corresponds to a two-dimensional ITO
(Indium Tin Oxide) glass substrate used in an organic LED. This
also forms an ITO film at the same time as drawing a quartz fiber.
Since the film can be formed at a lower temperature in comparison
with forming a silicon thin film, a plastic fiber may be used. On
this, what is called a bottom-emission type organic LED is formed
by a process flow similar to a two-dimensional substrate. In this
case, three colors of R, G and B are formed on fibers independent
of one another.
[0021] In an active matrix type TFT-OLED, a pixel driving circuit
composed of MOS transistor elements is formed starting at an SOI
fiber. In this case, it is acceptable to form organic LED's on the
same fiber or to form organic LED's on another fiber and combine
both fibers. Whether a single or combined fiber, pixels
corresponding to the number of rows are regularly arranged
correspondingly to pixel pitches in the direction perpendicular to
the display screen on one fiber to form one column of the display
screen. In case of a single fiber, a method of OLED is limited to a
front emission, but in case of a combined fiber, both of bottom and
front methods can be used. Further, the case of a combined fiber is
advantageous in that different technologies of TFT and OLED can be
developed and improved independently of each other.
[0022] As described above, although a "substrate" is in a special
shape of fiber, a conventional SOI process and an organic LED
process are applied as they are. However, two factors must be
considered in order to manufacture this.
[0023] A first factor is the shape of fiber. In order to make a
luminous body like OLED, a conventional circular or elliptic
section is advantageous. On the other hand, it is apparent that a
square (its corners are rounded in practice) is advantageous as
SOI. Thus, the shape must be selected according to application.
[0024] A second factor is a fabricating method specific to fiber,
and two methods are conceivable.
[0025] As a first method, there can be conceived a fundamental
production line in which a fiber of necessary length is wound
around a take-up jig in advance, a fiber drawn out from this passes
through apparatuses corresponding to processes and is wound around
another take-up jig. Various combinations based on properties of
processes and cost-effectiveness are conceivable with regard to the
number of apparatuses to be installed between the two take-up jigs,
namely, the number of processes, the length of apparatuses for one
fiber, the number of fibers in parallel, and whether intermittent
traveling or uniform traveling. In this case, an essential subject
is throughput and is fundamentally to make one fiber travel
uniformly at a speed as high as possible. The reason is that a
process proceeds collectively over a large area in a conventional
flat substrate but a process proceeds fundamentally in pixels in
case of a quartz fiber. That is, since this is the same as a fact
that a "point" corresponding to one pixel scans a two-dimensional
plane, a process time for each pixel is made very short and a
high-speed process being higher by 3 to 6 digits is made necessary
for realizing the same throughput as a conventional method. The
uniform traveling speed is a necessary property of the apparatuses
for making synchronization or for keeping the uniformity in film
formation and etching in case of forming a pattern on a substrate
traveling like in an exposure process as described above. In this
method, a fabricating apparatus is made "one-dimensional" in a way
and very small-sized, and a high-speed process is conceived to be
made realizable by replacing a vapor-phase process which a
conventional flat substrate is based on with a liquid-phase
process.
[0026] A second method is either a method of cutting the
above-mentioned one-dimensional substrate in proper lengths and
arranging and fixing these cut fibers on the surface of a circular
cylinder or a polygonal prism, and using this as a substrate, or a
method of making them into the shape of a "reed screen" and using
this as a so-called roller method. The former is a structure in
which a flat substrate is rounded in the shape of a cylinder in a
way, and a fabricating apparatus of it is greatly reduced in size
in comparison with that of a flat substrate. Further, it is
possible to increase greatly a process rate at the same time as
miniaturization of apparatuses by making process regions into a
linear shape corresponding to the fiber and using a concentrated
system of an exposure source, a vapor deposition source, an ion
source, a plasma source and the like.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIGS. 1(a), (b), (c) are figures showing the concept of
one-dimensional substrates. FIG. 1(a) shows an SOI substrate in
which an Si thin film crystal is formed on a quartz fiber being
square in section (its corners are rounded in practice) as a
concrete example, FIG. 1(b) shows an ITO substrate in which an ITO
film is formed on a quartz fiber being circular in section as a
concrete example, and FIG. 1(c) shows a structure in which a
thermal oxide film is formed on an Si film of FIG. 1(a).
[0028] FIGS. 2(a), (b) are figures showing the concept of a display
device formed out of a one-dimensional substrate. FIG. 2(a) is a
bird's-eye view of a configuration in which square fibers having
pixel driving circuits and wiring deposited in layers on them and
round fibers having OLED's formed on them are combined, and gate
lines are connected to the lower surface of the square fibers. FIG.
2(b) is a figure showing the connection between the said display
screen and an external circuit.
[0029] FIGS. 3(a), (b), (c) are figures showing the arrangement of
a pixel driving circuit and wiring on a square fiber. FIG. 3(a) is
a view of wiring of a pixel driving circuit, a connection pad to
OLED fiber, a signal line and a current feed line seen from one
side, and the wiring is continuous on the axis of fiber, and the
pixel driving circuit and the connection pad to OLED fiber are
repeated at intervals of pixel pitch with the same pattern. FIG.
3(b) is a sectional view of the square fiber. The signal line and
the current feed line run on two sides crossing the first side at
right angles. FIG. 3(c) shows terminal parts of the signal line and
the current feed line in a terminal portion on the same side as
FIG. 3(a).
[0030] FIGS. 4(a), (b) are figures showing the structure of a
round-shaped OLED fiber. FIG. 4(a) is a sectional view of a bottom
emission type, and OLED is formed in the third and fourth
quadrants, and emitted light is outputted from the first and second
quadrants. FIG. 4(b) is a plan view seeing the pad direction.
[0031] FIGS. 5(a), (b) are figures showing the structure of a
round-shaped front emission type OLED fiber. FIG. 5(a) is a
sectional view, and OLED is formed in the first and second
quadrants, and emitted light is outputted from there. FIG. 5(b) is
a plan view.
[0032] FIG. 6 is a pixel driving circuit diagram.
[0033] FIG. 7 is a view of a laminate structure of a display device
formed out of combined one-dimensional substrates seen from a
section perpendicular to the combined fibers.
[0034] FIG. 8 is a view of a laminate structure of a display device
formed out of combined one-dimensional substrates seen from a
section parallel with the combined fibers, and particularly showing
the configuration in the vicinity of terminals.
[0035] FIGS. 9(a), (b) are figures showing a process flow of TFT
starting at an SOI substrate with oxide film.
[0036] FIGS. 10(a), (b) are figures showing a process flow of a
bottom emission type OLED using an ITO substrate.
[0037] FIGS. 11(a), (b) are figures showing a process flow of a
front emission type OLED starting at a fiber with metal film.
[0038] FIG. 12 is a figure showing a fabricating process of a
one-dimensional substrate and a display device using the same.
[0039] FIG. 13 is a figure showing the concept of an apparatus for
fabricating an SOI fiber, an ITO fiber or the like being a
one-dimensional substrate.
[0040] FIG. 14 is a figure showing the concept of an apparatus
segmenting and arranging a one-dimensional substrate on a substrate
jig surface in order to make the segmented substrates into a
processed substrate.
[0041] FIGS. 15(a), (b), (c) are figures three kinds of
configuration examples for forming segmented fibers into a
"processed substrate". In FIG. 15(a), a "substrate jig" is
cylinder-shaped or round column-shaped and fibers are arranged and
fixed on the surface of this. FIG. 15(b) shows a substrate jig
having a fixing portion both ends of which are ring-shaped and a
lattice-shaped intermediate portion, and FIG. 15(c) shows a
processed substrate being in the shape of a "reed screen" made by
arranging in rows fibers having micro-clamp heads at both ends.
[0042] FIGS. 16(a), (b), (c) are figures showing principles of
apparatuses for film formation, dry etching, impurity doping and
the like on a cylindrical substrate. FIG. 16(a) shows a method
using ion cluster beams, metal spraying, atmospheric pressure
plasma and the like, and a convergent beam-shaped or concentrated
plasma state, and FIG. 16(b) (i), (b) (ii) show two forms of
cylinder-type CVD apparatuses. FIGS. 16(c) (i), (c) (ii) show
methods of sputtering apparatuses corresponding to FIG. 16(b) (i),
(b) (ii).
[0043] FIG. 17 is a figure showing a principle of an apparatus
applying resist, organic films and the like.
[0044] FIG. 18 is a figure showing a principle of a high-accuracy
exposure apparatus.
[0045] FIG. 19 is a figure showing a principle of an illumination
optical system.
[0046] FIG. 20 is a figure showing a principle of a 1:1 proximity
exposure optical system.
[0047] FIGS. 21(a), (b) (c) are figures showing principles of wet
processes such as development, exfoliation, wet etching, washing
and the like. FIG. 21(a) shows a wet tab of a horizontal type, FIG.
21(b) shows a wet tab of a vertical type and FIG. 21(c) shows a wet
method adapted to a reed-screen substrate.
[0048] FIGS. 22(a), (b) are figures showing a principle of
assembling combined fibers of TFT and OLED. FIG. 22(a) shows a
method of depositing bumps on a cylindrical substrate and FIG.
22(b) shows a method of connecting an OLED fiber to a TFT
fiber.
[0049] FIGS. 23(a), (b) are figures showing a method of arranging
combined fibers to make a display panel. FIG. 23(a) shows a frame
for arranging. FIG. 23(b) shows a positional relation between the
frame and fibers.
[0050] FIGS. 24(a), (b) are figures showing a method of attaching
gate lines to a combined fiber array. FIG. 24(a) shows a frame for
arranging gate lines. FIG. 24(b) shows a positional relation
between the frame and the gate lines.
[0051] FIG. 25 is a figure showing a principle of a
micro-welder.
[0052] FIGS. 26(a), (b) are figures showing a method of attaching
two common lines to a combined fiber array. FIG. 26(a) shows a
frame for arranging common lines. FIG. 26(b) shows a positional
relation between the frame and a common line.
DESCRIPTION OF THE SYMBOLS
[0053] 10: Quartz fiber of a square section, 10': Quartz fiber of a
round section, 11: Si thin film crystal, 11': ITO, 12: Thermal
oxide film, 20: TFT fiber, 21: OLED fiber, 25, 25': FPC or PCB, 26,
26': External driving circuit and the like, 31: Pixel driving
circuit, 32: Connection pad to OLED fiber, 33: Signal line, 34:
Current feed line, 35: Gate line connecting pad, 36: Signal line
terminal, 37: Current feed line terminal, 41: ITO, 42: OLED layer,
43: Cathode, 44: Transparent organic protective film, 45: ITO
reinforcing line, 46: Connection pad to TFT substrate, 50: Quartz
fiber, 51: Underlay electrode, 52: Cathode, 53: Organic EL layer,
54: ITO, 55: Inorganic passivation film, 56: ITO reinforcing
electrode, 57, Transparent organic protective film, 58: Pad, 60:
Pixel driving circuit, 61: ITO common electrode, 62: Organic EL
layer, 63: Cathode, 64: Common electrode line (ITO reinforcing
electrode), 65: TFT fiber and OLED fiber connecting pad, 66: Signal
line, 67: Current feed line, 68: Gate line, 70: TFT fiber, 71: OLED
fiber, 72: Gate line, 73: Common line, 74: Black resin, 75:
Transparent resin, 76, 76': Barrier film, 80: TFT fiber, 81: OLED
fiber, 82: Gate line, 83, 83': Common line, 84: Black resin, 85:
Transparent resin, 86, 86': Barrier film, 87, 87': External driving
IC and the like mounting TAB or FPC, 88, 88': PCB or frame, 90:
Thin film Si crystal, 91: Gate oxide film, 93: Gate electrode, 941:
Source, 942: Drain, 951, 052: LDD, 961-963: Through hole, 971-973:
973: Contact and wiring, 98: Second interlayer insulating film,
991-993: Contact and wiring, 100: Quartz fiber, 101: ITO, 102: ITO
reinforcing electrode, 103: Organic EL layer, 104: Cathode, 105:
Transparent organic protective film, 106: Pad, 110: Quartz fiber,
111: Underlay electrode, 112: ITO reinforcing electrode, 113:
Inorganic passivation film, 114: Cathode, 115: Organic EL layer,
116: ITO, 117: Transparent organic protective film, 118: Pad, 131:
Quartz fiber drawing portion, 132: Si, ITO and the like film
forming portion, 133: Resist protective film applying portion, 134:
Drying portion, 135: Winding mechanism, 141: One-dimensional
substrate reel, 142: One-dimensional substrate, 143: Resist
exfoliation, 144: Fiber segmenting head, 145: Substrate jig, 146:
Fiber traveling adjustment, 151: Segmented one-dimensional
substrate, 152: Cylinder- or round column-shaped substrate jig,
153, 153': Fixing ring, 154: Support, 155: Micro-clamp, 156:
Micro-chain, 160: Vacuum chamber, 161: Cylinder- or round
column-shaped substrate, 162: Process head, 163: Rotating
mechanism, 164: Cylinder-type CVD, dry etching and plasma doping
apparatus, 165: Cylinder-type CVD, dry etching and plasma doping
apparatus (also used as a substrate jig), 166: Cylinder-type
sputtering, dry etching and plasma doping apparatus, 167: Target or
electrode, 168: Target or electrode of cylinder-type sputtering,
dry etching and plasma doping apparatus (also used as a substrate
jig), 170: Cylinder- or round column-shaped substrate, 171: Resist
or resin dripping jig, 172: Rotating mechanism, 180: Cylindrical
substrate, 181: Rotating and translating mechanism, 182: Reducing
projection image forming lens, 183: Mask holder and lens servo
control mechanism, 184: Illumination optical system, 185: Excimer
laser, 186: Fiber position detecting head, 187: Signal
transmission, 188: Signal processing, 188: Servo control computer,
189: Servo control data transmission, 190: Collimated excimer beam,
191, 192: Split lens, 193: Secondary light source, 194: Condenser
lens, 195: Field lens, 196: Mask, 197: Image forming lens, 198:
Entrance pupil, 199: Image plane, 201: SOI fiber, 202: Cylindrical
lens, 203: Mask, 204: Collimated excimer beam, 211: Cylinder- or
round column-shaped substrate, 212: Horizontal-type tab, 213:
Carrying and rotating mechanism, 214: Vertical-type tab, 215: Reed
screen-shaped substrate, 216: Horizontal-type tab, 217-1-3:
Rotating and carrying mechanism, 221: Cylinder- or round
column-shaped substrate, 222: Rotating and carrying mechanism, 223:
TFT fiber, 224: Ink jet head, 225: OLED fiber, 226: TFT fiber, 227:
Fiber holding, positioning and fixing jig, 231: Combined fiber,
232: Combined fiber fixing frame, 233: OLED fiber, 234: TFT fiber,
235: Part of the fixing frame, 241: Gate line fixing frame, 242:
OLED fiber, 243: TFT fiber, 244: Gate line, 245: Part of the
combined fiber fixing frame, 251: Gate line, 252: TFT fiber, 253:
Micro-welder head, 254: Trapezoidal reflecting mirror, 255: Plane
mirror, 256: Condenser lens, 257: YAG laser, 258: Bump, 261: Common
line fixing frame, 263: Common line, 264: OLED fiber, 265: TFT
fiber, 266: Part of the common line fixing frame.
BEST MODE FOR CARRYING OUT THE INVENTION
[0054] Embodiments according to the present invention are described
with reference to the drawings in the following. FIGS. 1(a), (b),
(c) show a conceptual view of a one-dimensional substrate having a
quartz fiber as its base material.
[0055] In FIGS. 1(a), (b), (c), symbols 10 and 10' are quartz
fibers, which are made by the same method as a process of drawing
an optical fiber. FIGS. 1(a), (b) show respectively circular and
square sections as examples, but they can be elliptic, rectangular
or tube-shaped according to applications. The diameter of a fiber
or the length of one side of a fiber is made to be 800 .mu.m or
less so as to enable the fiber to be wound. Symbol 11 is a single
crystal or polycrystal film of Si, which is referred to as an SOI
fiber, and the thickness of an Si film in this case is about 100
nm. In FIG. 1(c), symbol 12 is an oxide film such as a thermal
oxide film or the like formed on the surface of Si. A
one-dimensional substrate in a second category is a substrate on
which a transparent electrode of ITO, zinc oxide, tin oxide or the
like of about 100 nm in thickness is formed instead of Si in FIGS.
1(a), (b). In this case, since a high temperature enough to form an
Si film is not necessary, it is possible also to use
multi-component glass, plastic base materials and other transparent
insulating materials instead of quartz.
[0056] FIG. 2(a) shows the concept of a TFT-OLED configuration
using combined one-dimensional substrates having square-shaped SOI
fibers 20 on which pixel driving circuits and wiring are formed and
circle-shaped ITO fibers 21 to 23 on which a plurality of organic
LED's are formed. A plurality of ITO fibers 21, 22 and 23 on which
the respective pixel columns of R, G and B (red, green and blue)
are formed are arranged at intervals of pixel pitch, and gate lines
24 are connected so as to cross them at right angles. An end
portion of each line is fixed on a wiring board (PCB: Printed
Circuit Board) 25 or 25' and is connected to a driver IC chip 26 or
26' mounted on the board as shown in FIG. 2(b). For example, a
plurality of red pixels (organic LED) are formed in a line on a
first ITO fiber 21, a plurality of green pixels are formed in a
line on a second ITO fiber 22, and a plurality of blue pixels are
formed in a line on a third ITO fiber 23.
[0057] FIG. 3(a) shows a sectional view of a square-shaped SOI
fiber on which a pixel driving circuit and wiring are formed, and
FIGS. 3(b), (c) show plan views of it. An organic EL
(electroluminescence) pixel driving switch circuit 31 is formed on
a face (A). And a connection terminal 32 to an organic LED, part of
a signal line 33 and part of a current feed line 34 are formed on
the same face and they each are connected to the driving switch
circuit 31. The signal line 33 and the current feed line 34
respectively pass through faces (B) and (C) perpendicular to face
(A) and reach parts of a face (D) opposite to face (A), and extend
in the longitudinal direction of fiber over the whole fiber. FIG.
3(c) shows the configuration in the vicinity of a fiber terminal on
the side (D), and symbol 35 is a pad for a gate line, and 36, 37
are respectively terminal pads of the signal line and current feed
line. The driving switch circuit 31 is composed of active elements
such as MOS transistors and the like.
[0058] A sectional view of a circle-shaped ITO fiber is shown in
FIG. 4(a) and a plan view in case that this is seen from below is
shown in FIG. 4(b). This is the configuration of what is called a
bottom emission type organic LED, in which an organic EL film 42 is
stacked on an ITO film 41 formed on the surface of a quartz or
plastic fiber 40 and a cathode metal film 43 separated for each
pixel is formed on this film 42. The organic LED is formed so as to
be accommodated in the third and fourth quadrants (lower half of
the figure) in FIG. 4(a), and emitted light is outputted from the
first and second quadrants (upper half of the figure). A pad 46 for
passing through a protective film 44 and connecting to the SOI
fiber is formed for each pixel. A metal electrode 45 is formed on a
part which does not interfere with OLED and the light output face
in the longitudinal direction in order to reinforce the resistance
value of ITO, and is made to be capable of coping with a
large-sized display screen.
[0059] In addition to the above-mentioned system, there is what is
called a front emission type organic LED system, and a sectional
view and a plan view of it are shown in FIGS. 5(a), (b). An
underlay metal film 51 and a cathode metal film 52 separated for
each pixel are formed on the surface of a quartz or plastic fiber
50 and an insulating layer 55 is formed on a part other than a
light emitting surface. An organic EL layer 53 is formed so as to
be accommodated in the first and second quadrants in FIG. 5(a), and
an ITO film 54 being a full-surface electrode is formed on this
film 53. The underlay metal film 51 extends into the third and
fourth quadrants, and a pad 58 for passing through the insulating
layer 55 and a protective film 57 and connecting to the SOI fiber
is formed for each pixel. An ITO reinforcing electrode 56 is formed
on the region other than the pad 58 and the light emitting
surface.
[0060] As the above-mentioned organic EL layered structure, a
structure of 2 to 6 layers is used. A configuration and material
for each color are as follows.
[0061] FIG. 6 shows an example of an equivalent circuit of a fiber
TFT-OLED. In FIG. 6, symbol 60 is a pixel driving circuit
corresponding to 31 in FIG. 3, 61 is an ITO electrode of an organic
LED, 62 is an organic EL layer, 63 is a cathode, 64 is a common
line including ITO and a reinforcing electrode, and 65 is a bump
for connecting to an SOI fiber. The symbols 61 to 65 correspond to
an OLED fiber. Symbol 66 is a signal line, 67 is a current feed
source line, and the symbols 60, 66 and 67 correspond to an SOI
fiber. Symbol 68 is an external gate line.
[0062] FIG. 7 is a sectional view of a fiber TFT-OLED structure in
a perpendicular direction to the fiber. Each combined line of an
SOI fiber 70 and an OLED fiber 71 corresponds to a pixel column of
R, G and B in the vertical direction of a display, namely, in the
column direction. A gate line 72 is connected to each pixel, while
it is enough that one or two external common lines 73 are only at
ends of the display screen. The reason is that a reinforcing metal
electrode is attached to an ITO common electrode. A net of fibers
composed of the symbols 70 to 73 has a black insulating resin 74
laminated onto the lower part of the light emitting portion of the
OLED fiber and a transparent resin 75 laminated onto the upper
part, and further have barrier films 76 and 76' against moisture,
oxygen and the like laid respectively on the upper and lower faces
for protection of the organic EL.
[0063] FIG. 8 is a sectional view of a fiber TFT-OLED structure in
the parallel direction with the fiber, and particularly shows the
configuration in the vicinity of terminal portions of it. A gate
line 82 is connected to each pixel so as to intersect a combined
TFT-OLED fiber composed of an SOI fiber 80 and an OLED fiber 81 at
right angles. It is enough that common lines 83 and 83' for
connecting common electrodes of OLED exist only at end parts of the
display screen. A signal line and a current feed line on each fiber
are connected to an external circuit. Here, they are connected to
TAB or FPC 87 and PCB 88 mounted with driving ICs. Barrier films 86
and 86' are arranged further outside the gate line 82 and the
common lines 83 and 83'.
[0064] In the above-mentioned display device, a combined
one-dimensional substrate is formed by combining a one-dimensional
substrate on which a pixel driving circuit 31 composed of MOS
transistors and the like formed on an SOI fiber 20 has been formed
and a one-dimensional substrate composed of organic LED pixels
formed on ITO fibers 21 to 23 with each other at each corresponding
pixel. This combined one-dimensional substrate forms one column of
the display screen.
[0065] Additionally, in order to introduce an image signal from the
outside into each pixel from one end of a fiber, a signal line 33
of a linear conductor running in the longitudinal direction of
fiber and a current feed source 34 of a linear conductor for
feeding current to be put into an organic LED 42 or 53 forming each
pixel are formed on the same SOI fiber 20.
[0066] These combined fibers 20 to 23 are arranged regularly
correspondingly to pixel pitches in the horizontal direction of the
display screen in number necessary for the number of columns of the
display screen, and perpendicularly to these combined fibers 20,
gate lines 24 of linear conductor for introducing signals of timing
and the like for pixel display into pixel driving circuits 31 are
connected to SOI fibers 20. And common electrode lines 61 for
commonly connecting transparent electrodes 41 or 54 being the
emitted light outputting faces of the ITO fibers 21 to 23 provided
with organic LED's 42 or 54 are connected.
[0067] External driving circuits 26 and 26' for applying a signal
for driving a pixel or a control signal to the ends of these signal
line 33 and gate line 24 on the fiber 20 are connected to a current
source common to each current feed source 34, and a same potential
source is connected to each common electrode line 61. The whole net
formed in such a way is provided with a transparent organic resin
or the like having rigidity or flexibility on the light emitting
side of it and a black organic resin or the like on the opposite
side and the above-mentioned meshed display screen is protected by
both of these resins and thereby a TFT-organic LED light emission
type display device flattened to 3 mm or less in thickness is
formed. An SOI fiber with oxide film may be used in place of the
SOI fiber 20.
[0068] FIGS. 9(a), (b) are figures showing an example of a TFT
process in case of using an SOI fiber with oxide film. First, as
shown in steps (1-3) of FIGS. 9(a), (b), an island of a silicon
film 90 including an oxide film 91 is formed. In case that a pixel
driving circuit of FIG. 6 is made to be n-channel as a whole
according to the design rule of 0.5 .mu.m and a layout in case of
"L/W=2/2 .mu.m" is performed, the area of a circuit portion is
28.times.24 .mu.m. Even if various circuit forms other than this
are adopted, it is enough that the area of an island is 50
.mu.m.sup.2.
[0069] Next, as shown in steps (4-6) and (7-10) of FIGS. 9(a), (b),
the side faces of the silicon film 90 are covered with an oxide
film by means of plasma oxidation, thermal oxidation, oxide film
formation and the like, and a gate electrode 93 is formed on the
oxide film. Metal tungsten, tungsten silicide or the like was used
as the gate electrode 93. Subsequently, as shown in steps (11-18)
of FIGS. 9(a), (b), a structure of n-channel in which source and
drain domains 941 and 942 have LDD (Lightly Doped Drain) domains 95
of about 1 .mu.m in width is formed. In introduction of impurities,
first a low-concentration ion implantation was performed and next a
high-concentration ion implantation was performed after adjusting
the thickness of resist film covering end portions of the gate
electrode 93 so as to be 1 .mu.m. As another method of introducing
impurities, windows having areas corresponding to source and drain
domains were made in the oxide film and first a low-concentration
ion implantation was performed by plasma doping and next in the
same manner as described above, a high-concentration ion
implantation was performed by plasma doping after adjusting the
thickness of resist film covering end portions of the gate
electrode 93 so as to be 1 .mu.m.
[0070] In either method, thereafter, as shown in steps (19-22) and
(23-28) of FIGS. 9(a), (b), a first interlayer insulating film 96
was formed and through holes 961, 962 and 963 were made in this
film, and the respective wirings 971, 972 and 973 of the source,
gate and drain were formed. At this time, Ti was used as barrier
metal and Al was used as metal for wiring. At this stage, wiring
for connecting elements in the pixel driving circuit and part of
wiring from the circuit to a signal line and a current feed line
are formed.
[0071] Further, as shown in steps (29-31) and (32-39) of FIGS.
9(a), (b), a second interlayer insulating film 98 was formed, V and
part of connection to said pixel driving circuit and a pad for gate
and wirings 991 to 993 in the circuit were performed. Next, an Al
film for wiring is formed on a side face of the fiber and the
connection between a wiring pattern and the circuit is completed,
and next the second interlayer insulating film is formed again on
the side face and an Al film is formed and patterned and the
connection to the pad for gate is completed.
[0072] On the other hand, a process diagram of an OLED fiber
(sectional view) is shown in FIGS. 10(a), (b). An illustrated
method is of a bottom emission type. As shown in step (1) of FIGS.
10(a), (b), a one-dimensional substrate at the starting point is
what is called an ITO fiber on which an ITO film 101 has been
formed in advance. On this, an Al reinforcing line 102 was formed
by means of mask formation or resist lift-off. The first and second
quadrants in case of representing a sectional view in the figures
in the X-Y coordinates are the output face of an EL luminescence,
and as shown in steps (2-4) of FIGS. 10(a), (b), an EL layer 103 is
formed in the third and fourth quadrants. Then, as shown in step
(5) of FIGS. 10(a), (b), a cathode metal electrode 104 on the EL
layer 103 is separated for each pixel and formed by mask vapor
deposition. Further, as shown in steps (6-9) of FIGS. 10(a), (b), a
transparent photosensitive resin 105 is applied to all over them
and is exposed and hardened except a through hole to a cathode. An
unexposed part is made into a through hole by development and is
made into a connection pad to the SIO fiber by filling this hole
with low-melting point solder, conductive adhesive or the like 106
by means of ink jet, dispenser or the like.
[0073] FIGS. 11(a), (b) are a process diagram of an OLED fiber of a
front emission type. As shown in steps (1-6) and (7-8) of FIGS.
11(a), (b), a pattern 111 is formed for making a metal film on a
one-dimensional substrate metal film fiber 110 into connection
terminals to an underlay electrode and an SOI substrate in pixels
and next an insulating film 113 is formed on the semicircular part
opposite to a luminescence part including the said terminal part. A
through hole to a terminal of the underlay metal is also formed at
the same time as the time of forming a pattern of this insulating
film. Next, an ITO reinforcing metal electrode 112 is formed so as
not to overlap the terminal part on the said insulating film, but
at this time, part of the metal film forms a connection terminal to
the underlay terminal electrode on the insulating film 113 through
a through hole. Next, as shown in steps (19), (20-23) and (25) of
FIGS. 11(a), (b), a cathode electrode 114 and an organic EL layer
115 are mask-deposited so as no to extend to the lower semicircle
and an ITO 116 is mask-deposited so as to come into contact with
the reinforcing electrode and thereby an OLED portion is formed. As
shown in steps (26) of FIGS. 11(a), (b), the whole of them is
covered with a transparent photosensitive resin 117, which is
optically hardened except the above-mentioned terminal part and the
terminal part forms a through hole by means of development and here
a connection bump to the SOI substrate is formed by means of ink
jet, dispenser or the like.
[0074] A concrete method of performing the above-mentioned
processes, a method of fabricating a device structure and a
principle of a fabricating apparatus are described in the
following.
[0075] The whole fabricating process is roughly divided into four
processes and a flow diagram of the roughly divided processes is
shown in FIG. 12. Since a fiber one-dimensional substrate
fabricating process corresponds to a process of fabricating a wafer
or an SOI substrate by means of an existing two-dimensional
technology, it may be thought to be independent of a display
fabricating process. A segment arraying process is a process of
cutting these one-dimensional substrates suitably for a display
size, arranging and fixing them on the surface of a cylinder or a
polygonal prism or on the inner face of a cylinder, and making them
newly into a "substrate" in a fabricating process of TFT and OLED.
A fabricating process of TFT and OLED is the same as that of a
two-dimensional substrate as a process flow as described above. The
last process is a process of assembling the finished fibers into a
product.
[0076] This embodiment adopts an HD-TV of 16:9 in aspect ratio and
50'' in diagonal length and a 15'' SXGA as concrete objects as
display. In the former, in full specifications the definition is
1080.times.1920 (the display screen size is 1106.times.622 mm), the
pixel size is 0.576.times.0.576 mm, and the pitch of each color of
R, G and B is 0.192 mm. As the method, a combined type was used and
a quartz fiber of 125 .mu.m square was used as TFT and a quartz
fiber of 125.mu..phi. in diameter was used size is
228.6.times.304.8 mm, in case of 15'' display, the definition is
1024.times.1280, the pixel size is 0.223.times.0.223 mm, and the
pitch of each color of R, G and B is 0.08 mm, and a fiber of 70
.mu.m square and a fiber of 70.mu..phi. in diameter were used. The
length of fiber for each color of the HD-TV is about 1200 m. Since
the throughput time of an existing large-sized two-dimensional
substrate is about 60 seconds, the traveling speed in a fiber
one-dimensional substrate fabricating process was set at about 20
m/sec for the same throughput as this.
[0077] FIG. 13 shows a fabricating principle of a one-dimensional
substrate of SOI, ITO or the like using a quartz fiber. Symbol 131
is a conventional quartz fiber drawing stage, in which a quartz
fiber of a specified diameter was formed and next, in stage 132 an
Si film was formed as Si crystal in a high-temperature atmosphere
by means of CVD, thermal spraying, molten liquid coating-cooling
and the like, and was applied with resist as a protective film in
stages 133 and 134 for winding the fiber, and was wound around a
roll 135. In the stage 132, an apparatus adapted to ITO, metal
films and the like is used and a substrate is formed in similar
processes in the following.
[0078] FIG. 14 shows a principle diagram of a segment arraying
process. A fiber 142 covered with a protective film of resist is
drawn out from a roll 141 having a one-dimensional substrate wound
around it, is stripped of the resist and is washed in a stage 143
on the way, and the fibers segmented by a cutting and arranging
apparatus 144 are fixed on the surface of a "substrate jig" 145
being a "processed substrate" making jig.
[0079] FIGS. 15(a), (b), (c) show conceptual diagrams of "processed
substrates" formed by a segment arraying process. Symbol 151 shown
in FIG. 15(a) is a segmented fiber and symbol 152 is a fixing jig
for making these fibers into a "processed substrate". Various
structures are applied to this fixing jig, but a fundamental
structure is a cylinder, a round column or a polygonal prism having
a rotation shaft and has grooves for positioning fibers formed on
the surface of it along the axial direction. Although not
explicitly shown in the figure, fibers on the jig are fixed at both
ends.
[0080] Another fundamental structure is a structure having two
rings 153 and 153' joined by supports 154 as shown in FIG. 15(b)
and in this case also, has grooves for positioning fibers formed on
the surface of the rings, and has a configuration for keeping the
fibers straight by means of fixing and tension at both ends. In
case of a cylindrical shape, the said jig is 76.4 .phi.in diameter
and 622 mm in effective length for a 50'' HD-TV, and 28.5 .phi.in
diameter and 229 mm in effective length for 15'' SVGA. Therefore,
it has a "footprint" of 1/14 for an HD-TV and 1/10 for a 15''
display in comparison with a flat substrate, and as a result, can
realize making the apparatus greatly small-sized.
[0081] Further another structure holds both ends of fibers 151 with
micro-clamps 155 and fixes them on a chain 156, as shown in FIG.
15(c), and this is hereinafter referred to as a "reed screen-shaped
substrate". This is a form convenient for a roll-to-roll processing
method as used for an organic film. Processing of each face of a
fiber is made easy by using a structure being a simple clamp and at
the same time being able to turn within a certain angle as the
micro-clamp 155. The micro-clamp can be naturally used in said
cylindrical substrate also.
[0082] Processes of TFT and OLED described in FIGS. 9 to 11 use the
same processes and film materials as existing processes of a
two-dimensional substrate. Metal materials for electrodes, wiring
and the like are W, tungsten silicide, Ti, Al and the like, and
inorganic insulating materials are SiO.sub.2, SiN and the like, and
organic insulating materials are photosensitive transparent resins.
As a film forming method, sputtering, ion cluster beams, metal
spraying and the like are used in case of metal films, and various
kinds of CVD are used in case of insulating films. Principle
figures of these film forming methods for a cylindrical substrate
are shown in FIGS. 16(a), (b), (c).
[0083] FIG. 16(a) is a form in which there is installed a process
head 162 generating a convergent beam-shaped or concentrated plasma
state such as ion cluster beams, metal spraying, atmospheric
pressure plasma or the like in a vacuum chamber 160, and is a
method of one-dimensionally forming films in the axial direction of
a cylindrical substrate 161. Film formation and processing of the
whole surface of the substrate are performed by means of a rotating
mechanism 163.
[0084] FIG. 16(b) shows two forms of cylinder-type CVD apparatuses.
FIG. 16(b) (i) is the case that there is a cylindrical substrate
161 inside an external cylinder 164, and (ii) is a method in which
fibers are fixed on the inner wall of a cylindrical substrate 165,
and in this case the cylindrical substrate forms the external wall
of a CVD apparatus.
[0085] FIG. 16(c) is a method of a sputtering apparatus
corresponding to FIG. 16(b), and in FIG. 16(c) (i), an external
cylinder 166 forms a vacuum chamber, inside which one or plural
sputtering targets 167 are set and film formation is performed on
the whole surface of the cylindrical substrate 161 by means of a
rotating mechanism 163. In FIG. 16(c) (ii), a method in which a
cylindrical substrate itself is a substrate holder and serves also
as the external wall of a vacuum chamber according to
circumstances, and a sputtering target 168 is set on the central
axis.
[0086] Dry etching and the apparatus are essentially the same
process and apparatus principle as plasma CVD (P-CVD) and
sputtering in film formation. That is to say, dry etching is
performed by either method that the process head introduces an
etching gas for atmospheric pressure plasma in FIG. 16(a), or
changes a CVD gas to an etching gas in FIG. 16(b), or uses only
electrodes instead of targets in FIG. 16(c).
[0087] Although various methods and apparatuses for film formation
and dry etching have been described above, a similar
photolithography to a two-dimensional substrate is applied to a
cylindrical substrate in pattern formation. FIG. 17 shows a concept
of a resist applying method. Symbol 171 in the figure is a
configuration for pouring out a resist agent from a slit onto a
cylindrical substrate 170, rotates the cylindrical substrate by
means of a rotating mechanism 172, and applies the resin agent
uniformly on the whole surface. In case of a jig of a type of FIG.
15(b),there is adopted a method of forming a uniform resist layer
on the whole surfaces of fibers by dipping the whole cylindrical
substrate in a liquid resist and rotating it around the central
axis. The cylindrical substrate applied with resist is pre-baked in
a cylindrical baking furnace.
[0088] FIG. 18 shows a conceptual figure of a high-accuracy
exposing apparatus used for a pixel circuit TFT. The exposing
apparatus is of a method of exposing fibers, fiber by fiber, on a
cylinder- or polygonal prism-shaped substrate 180, and symbol 181
in the figure is a mechanism turning the substrate around the
central axis and simultaneously moving it in the axial direction
also. Symbol 182 is a 5:1 reducing projection image forming lens of
5 mm.sup.2 in exposure area and a plurality of the projection
lenses are coupled to each other. For alignment, a servo control
mechanism 183 controls each lens independently in the three
directions of X-, Y- and Z-axes. As for control data, the servo
control of the lens system is performed by reading the positional
coordinates of each fiber at a high speed by means of an optical
head 186 for detection at the stage precedent to exposure,
inputting the read positional data through a transmission line 187
into a memory and computation system 188, and transmitting a
control signal from the memory and computation system 188 through a
transmission line 189 to the servo control mechanism 183. A
mechanical probe for sensing the side face of a fiber may be used
in place of an optical head. An excimer laser of 308 nm or 248 nm
in wavelength is used as a light source 185 of this exposure
system. An illumination optical system 184 is a conventional
Koehler illumination system and uses cylindrical lenses and the
like, and its illumination area is 0.2 mm in width, corresponds to
the length of the image forming lens system having lenses coupled
and is in the shape of a slit of at least 250 mm in length.
[0089] FIG. 19 shows an equivalent optical system of the exposure
optical system. Collimated light 190 of an excimer laser made into
an appropriate shape is made into a secondary light source by split
lenses 192, and the secondary light source 193 and a condenser lens
194 irradiates a mask 196 with a light uniformly distributed in a
specified shape. A field lens 195 forms a secondary light source
image in an entrance pupil 198 of the image forming lens 197 to
form a mask image on an image plane 199. The optical system of 190
to 195 in the figure represents a slit-shaped illumination in the
direction of X- or Y-axis and practically consists of two optical
systems. This is a common optical system but is separated into
individual optical systems after the field lens 195.
[0090] The output of the excimer laser in this case is 10 W at 2
kHz, namely, 5 mJ/1 shot. Therefore, the energy density of the
slit-shaped illumination part is 10 mJ/cm.sup.2 at the light source
and comes to be 5 mJ/cm.sup.2 on the assumption that loss in the
optical system is 50%. Since a necessary dose of a chemical
sensitizer resist is about 30 mJ/cm.sup.2, the exposure of 6
shots/site is necessary. The effect of spatial coherence of the
excimer laser is also cancelled by the 6 shots. Therefore, the
total number of shots onto a cylindrical substrate for 50'' HD-TV
is 633/50.times.1920.times.6=149760, which makes a laser of 2 kHz
need 75 seconds and the necessary time of a high-accuracy exposure
process including a servo control time is about 2 minutes.
[0091] Although it is a pixel switch exposure method needing a
high-accuracy exposure that has been described above, a 1:1
proximity exposure as shown in FIG. 20 was used in case of a
pattern spreading over a wide area without requiring an accuracy as
high as TFT, for example, a pattern of wiring in pixel switches and
pads as well as a pattern in the axial direction of fiber and the
like. A cylindrical lens 202 designed so as to condense an incident
light beam 204 on the center of fiber with an angle sufficiently
covering corners of a fiber 201 is placed in parallel with the
fiber, and thereby a mask pattern 203 is projected along the curved
surface of the fiber. One or many cylindrical lenses described
above are configured so as to fit alignment with the fiber. In case
of using said excimer illumination system as a light source in the
said exposure, a process time is shortened to about 30 seconds due
to 1:1.
[0092] FIGS. 21(a), (b), (c) show principle figures of wet
processes such as development, exfoliation, wet etching, washing
and the like. FIG. 12(a) is a method of processing a cylindrical
substrate 211 in a horizontal-type wet tab 212 and performs a
plurality of wet processes by a rotating and conveying system 213
in the tab. FIG. 21(b) is the case of using a vertical-type tab
214. FIG. 21(c) is a method adapted to a reed-screen substrate 215
in the shape shown in FIG. 15(c), and makes it pass through a wet
tab 216 by means of a roller conveyer system of 217-1 to 217-3.
After washed, it is dried by jetting or blowing dry and clean air,
nitrogen or the like in an air knife shape.
[0093] As impurity introducing methods, two methods of ion
implantation and plasma doping are used. The ion implantation uses
a process head in FIG. 16(a) made into a slit-shaped ion gun. A
method and apparatus for plasma doping has essentially the same
process and apparatus principle as P-CVD and sputtering in film
formation. That is to say, doping is performed by either method of
making the process head introduce an impurity gas for atmospheric
pressure plasma in FIG. 16(a), or change a CVD gas to an impurity
gas in FIG. 16(b), or introduce an impurity gas using only
electrodes instead of targets in FIG. 16(c). An impurity activation
uses a conventional thermal annealing method. And hydrogen
annealing in the process also uses a hydrogen furnace similarly to
a conventional semiconductor process.
[0094] In order to make the fiber made in such a way into a
two-dimensional flat display, solder or conductive adhesive able to
be used at a low temperature giving no damage to OLED is first
deposited on pad portions of a fiber 223 on each cylindrical
substrate 221 or reed screen-shaped substrate of TFT and OLED by
means of ink jet 224 or the like, as shown in FIG. 22(a). At this
time the cylindrical substrate is turned and moved by a shaft 222.
The movement in the axial direction may be performed by the ink jet
head 224. As shown in FIG. 22(b), one 225 (223) of both fibers on
which bumps have been formed in such a way is removed from the
substrate or the like is aligned with and then press-joined with
the other fiber 226 by means of a jig 227 for holding and
press-joining both ends. A test of connection of both fibers is
performed at this stage, depending on a processed substrate jig of
fiber.
[0095] Next, these double fibers 231 are fixed on a fiber fixing
frame 232 shown in FIG. 23(a) in order of R, G and B at intervals
of pixel pitch. This frame 235 (232) is more outside than OLED
fibers 233 so as not to hinder connection of gate lines described
below as shown in FIG. 23(b). After the fixing, a low-melting point
solder or the like is deposited on a pad for gate of TFT fiber 234
from the direction of arrow 236 by means of ink jet or the like in
the same manner as described above. A connection test of both
fibers may be performed at this stage. And unnecessary end portions
are cut at this stage. Next, the fibers and gate lines are
connected to each other.
[0096] A frame 241 on which copper wires for gate are stretched at
intervals of pixel pitch as shown in FIG. 24 forms partially a
nested structure with a fiber fixing frame 232 shown in FIG. 23. A
copper wire has a low-temperature solder put onto it in advance. A
positional relation between fibers 242, 243 and the copper wires is
as shown in FIG. 24(b), and the copper wires are joined with the
lower faces of TFT fibers 243 under OLED fibers 242 by means of
thermal press-joining or a laser micro-welder shown in FIG. 25.
[0097] In case of the latter, the frame of FIG. 24 is on an X-Y
stage and gate lines 251 are running vertically (Y) to the page
plane as shown in FIG. 25. A laser welder head emits a pulse beam
synchronously with the position of a gate pad. When one gate line
is finished, the frame is moved by a vertical pixel pitch by the
X-stage and the same operation is performed. The gate line 251 is a
conventional copper wire of 100 .mu.m in diameter and the gap
between the copper wires is 476 .mu.m in case of a 50'' HD-TV. An
optical head portion 253 of the micro-welder is a micro-optics
optical system composed of a trapezoidal prism 254, a mirror 255
and micro-lenses 256. A pulse laser beam 257 is split by the
trapezoidal prism and is radiated onto a bump 258 on a TFT fiber
252 from both sides of a copper wire.
[0098] As a laser, the fundamental wave of a YAG laser is used and
is condensed to 10 .mu.m.phi. or less in diameter by the lenses
256, and thereby the bump is molten to weld. The output of an
original laser light source must be in a TEM.sub.00 mode for
optical condensation of 10 .mu.m.phi. or less in diameter. Due to
this, a fiber being ordinarily used as a light-guide system is not
used but a two-lens beam expander being as simple as possible and
an optical system of FIG. 25 are used. Since the vertical pixel
pitch of a HD-TV now conceived is 576 .mu.m, when a light source of
20 kHz in oscillation frequency is used, the speed of movement
becomes about 12 m/sec. A necessary time for traveling of one gate
line is about 0.1 second and therefore a necessary time for
traveling over the whole display screen is about 108 seconds. In
practice, the operations of acceleration, deceleration, one pixel
pitch movement and the like each need a little less than 0.1
second, and the necessary time for the whole display screen was
about 400 seconds, namely, about 7 minutes in case of using a
single head but one display plate could be completed in one minute
or less by using many heads.
[0099] For connection of OLED with common electrodes, two wires are
connected to OLED fibers at the ends not appearing in the display
screen. Due to this, a common line frame 261 as shown in FIG. 26(a)
has a structure in which two conductive wires 263 stretched on this
frame are positioned over OLED fibers 264 as shown in FIG. 26(b).
OLED fibers and the two common wires have a conductive adhesive for
connection at a low temperature deposited on them in advance by
means of ink jet or the like and thereby are thermally press-joined
at a low temperature.
[0100] After the above assembly has been finished, a lighting
inspection is performed using a prober, and particularly inspection
of the above-mentioned connection is performed. After it has been
confirmed that the connection is perfect, a signal driver IC chip,
a current source, a gate driver IC chip, a common electrode and the
like are mounted. A signal driver IC chip and a current source are
connected to an end of a TFT fiber.
[0101] These circuit components are mounted on a flexible or rigid
circuit board comprising a multilayered wiring of 0.4 mm in
thickness and they each have a terminal formed for a vertical pixel
column. A method of connecting them with fibers is entirely the
same as described above. A gate line and a common line are disposed
in the side where a flexible or rigid circuit board comprising a
multilayered wiring and having similarly a gate driver IC chip and
a common electrode mounted on it intersects the above-mentioned
board at right angles and are connected in a similar manner. After
inspection of these mounting has been ended, as shown in FIGS. 7
and 8, a black paint containing resin is poured onto the side
opposite to the light output face side of fibers and next a
transparent resin is poured onto the light output face side of the
fibers, and the whole is shaped into a flat panel so as to be 1 mm
or less in thickness to complete a display panel.
[0102] As described above, according to the present invention, an
ultra-thin, large-sized and high-definition display of 2 mm or less
in thickness can be manufactured at low cost. Therefore, the range
of application is expanded to various applications of a full-scale
wall-mounted TV, medical appliance, electronic paper and the like.
Due to a quite new production apparatus, it launches a new industry
and at the same time, enables the speed-up of technological
innovation since the apparatus itself is small in size and low in
production cost. And although the content is not referred to, a
ripple effect of these apparatus and process on things other than
display is great and particularly their meaning as a preceding
stage leading to nano-technologies is great.
[0103] And in case of a display of a mobile phone or a display of 7
to 10 inches, an organic EL display may be made by using a flat
substrate made of a silicon wafer or glass substrate having driving
circuit elements formed on it and combining the flat i' substrate
with an array of OLED fibers. In case of a relatively small-sized
display, a silicon wafer process has an advantage of being capable
of being procured very inexpensively since a large number of
semiconductor devices are in use. However, in a display using a
conventional two-dimensional substrate, it is very difficult to
make a high-definition display of 50 .mu.m or less in pixel size.
The reason is that an organic EL element is made using a metal
shadow mask and since a different mask is used for each color of
red, green and blue, alignment must be performed for each color and
it is very difficult to attain an alignment accuracy of 5 .mu.m or
less in a vacuum apparatus. As a relative positional accuracy of a
mask and a substrate, it is conceivable that a processing accuracy
of a mask is 3 .mu.m or less, an alignment accuracy is about 5
.mu.m and a slippage caused by deformation due to thermal expansion
during a process is 1 to 3 .mu.m. Accordingly, the comprehensive
accuracy comes to be about 5 to 10 .mu.m, and it is difficult to
realize a pixel size equal to or less than the above-mentioned
pixel size in industrial level. However, a method using a
one-dimensional substrate can form and arrange organic EL films
independently for each color using a reel-to-reel method. In this
case, since a mask may be a shadow mask having one or several
slits, the mask can be made with accuracy of 1 .mu.m or less, and
it is possible to form a film easily with high accuracy by fixing
said mask and intermittently moving a one-dimensional substrate
over said mask. It is a matter of course that organic EL films can
be continuously manufactured by moving said mask synchronously with
movement of a one-dimensional substrate.
[0104] In such a way, in case of a relatively small-sized display,
an inexpensive and high-definition display can be realized by
combining an OLED fiber array with a TFT circuit substrate made of
a two-dimensional substrate. In case of using a silicon wafer,
since the performance of TFT is more excellent in comparison with
polycrystalline TFT, its high-speed response can be improved, its
circuit also can have a complicated function added to it, and its
color compensation and the like can be also improved.
* * * * *