U.S. patent application number 10/714700 was filed with the patent office on 2004-06-03 for thin film transistor liquid crystal display and method for manufacturing the same.
This patent application is currently assigned to Prime View International Co., Ltd.. Invention is credited to Lin, Wen-Jian.
Application Number | 20040104434 10/714700 |
Document ID | / |
Family ID | 21679154 |
Filed Date | 2004-06-03 |
United States Patent
Application |
20040104434 |
Kind Code |
A1 |
Lin, Wen-Jian |
June 3, 2004 |
Thin film transistor liquid crystal display and method for
manufacturing the same
Abstract
There is provided a reflection type/transflection type thin film
transistor liquid crystal display, including an insulating
substrate, a thin film transistor formed on the insulating
substrate, a transparent electrode made of indium-tin-oxide formed
on the thin film transistor and electrically contacted with a
source region and a drain region of the thin film transistor, and a
curved conducting structure with an inclination of 3 to 20 degrees
formed on the transparent electrode.
Inventors: |
Lin, Wen-Jian; (Hsinchu,
TW) |
Correspondence
Address: |
VOLPE AND KOENIG, P.C.
UNITED PLAZA, SUITE 1600
30 SOUTH 17TH STREET
PHILADELPHIA
PA
19103
US
|
Assignee: |
Prime View International Co.,
Ltd.
Hsinchu
TW
|
Family ID: |
21679154 |
Appl. No.: |
10/714700 |
Filed: |
November 17, 2003 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
10714700 |
Nov 17, 2003 |
|
|
|
10139852 |
May 7, 2002 |
|
|
|
Current U.S.
Class: |
257/347 ;
438/151; 438/164 |
Current CPC
Class: |
G02F 1/133553
20130101 |
Class at
Publication: |
257/347 ;
438/151; 438/164 |
International
Class: |
G02F 001/136; H01L
021/00; H01L 027/12; H01L 031/0392 |
Foreign Application Data
Date |
Code |
Application Number |
Aug 24, 2001 |
TW |
90120948 |
Claims
What is claimed is:
1. A method of manufacturing a thin film transistor liquid crystal
structure comprising the steps of: (a) providing an insulating
structure; (b) forming a gate structure on a portion of said
insulating substrate; (c) forming an insulating layer on said gate
structure and said insulating substrate; (d) forming a first
semiconductor structure and a second semiconductor structure on
said insulating layer; (e) forming a conducting layer on said
insulating layer and said second semiconductor structure; (f)
etching said conducting layer to define a source region and a drain
region and a curved structure with an inclination; and (g) forming
a transparent electrode on said curved structure, wherein said
transparent electrode is electrically contacted with said source
region and said drain region.
2. The method of claim 1 wherein an angle of said inclination is
about 3 to 20 degrees.
3. The method of claim 1 wherein said conducting layer is formed
from a metallic material.
4. The method of claim 1 said curved structure is an awl-shaped
structure.
5. The method of claim 1 wherein said curved structure is a conical
structure.
6. The method of claim 1 wherein said transparent electrode is
formed from indium-tin-oxide.
7. A thin film transistor liquid crystal display comprising: an
insulating substrate; a thin film transistor formed on said
insulating substrate; a curved structure with an inclination formed
on said insulating substrate; and a transparent electrode layer
formed on said curved structure.
8. The thin film transistor liquid crystal display of claim 7
wherein an angle of said inclination is about 3 to 20 degrees.
9. The thin film transistor liquid crystal display of claim 7
wherein said curved structure is an awl-shaped structure.
10. The thin film transistor liquid display of claim 7 wherein said
curved structure is a conical structure.
11. The thin film transistor liquid display of claim 7 wherein said
transparent electrode is formed from indium-tin-oxide.
Description
RELATED APPLICATIONS
[0001] The present invention is a divisional of co-pending U.S.
patent application Ser. No. 10/139,852, filed May 7, 2002 which is
incorporated by reference as if fully set forth, and which claims
priority to Taiwanese (R.O.C.) Patent Application No. 90120948
filed on Aug. 24, 2001.
FIELD OF THE INVENTION
[0002] The present invention is related to a liquid crystal display
(LCD), and more particularly, the present invention is related to
reflection type/transflection type thin film transistor liquid
crystal display and the manufacturing process thereof.
BACKGROUND OF THE INVENTION
[0003] With the increasing progress in the manufacturing technique
of flat panel display, liquid crystal display (LCD) has been
extensively employed as a main stream display device. The LCD uses
electric field to control the alignment of the liquid crystal
molecules in the liquid crystal layer, and determine whether the
polarized light can pass through the liquid crystal layer to make a
dark display or a white display. As a result, how to get a brighter
display for LCD has become a significant target for the research on
the manufacturing process of the liquid crystal display device.
[0004] For a reflection type or a transflection type thin film
transistor liquid crystal display (TFTLCD), its brightness is
determined by the incident light emitted from a light source and
the reflecting light thereof. If it is desirable to obtain a
brighter display, the intensity of light scattering in a direction
perpendicular to the display screen has to be increased. For this
purpose the reflective characteristic of the reflector thereof has
to be intensified. As shown in FIG. 1(a), a resin coating 114
comprised of a plurality of transparent resin beads 113 having a
penetrative characteristic is formed on a first transparent
electrode layer 111, in order that when light passes through the
first transparent electrode layer 111 and the color filter 112 and
enters the resin coating 114, a deflection is made to the light
departing from the resin coating 114 due to the collisions against
the transparent resin beads 113. Further the light is scattered by
way of the electric field applied between the second electrode
layer 116 on the TFT array substrate 115 and the first transparent
electrode layer 111, and the scattered light is then reflected by
the reflector 117. The conventional reflection type/transflection
type TFTLCD of FIG. 1(a) is advantageous in terms of the increase
in the light scattering angle, and thus the direction of reflection
is easy to be controlled. However, the reflection
type/transflection type TFTLCD of FIG. 1(a) is disadvantageous by
that the direction of light scattering is quite difficult to be
controlled precisely by adjusting the locations of the transparent
resin beads 113.
[0005] To solve the foregoing drawbacks experienced by the prior
art, a novel manufacturing process for the reflection
type/transflection type TFTLCD that forms the resin coating
directly on the second electrode layer on the TFT array substrate
has been addressed. As shown in FIG. 1(b), when light passes
through the color filter 122, light scattering effect will come
about due to the electric field applied between the second
electrode layer 126 and the first electrode layer 121. The
scattered light will then be reflected by the resin coating 124.
Because the resin coating 124 is a curved structure, its uneven
surface can be used to regulate the magnitude of the angle of
reflection, and thereby the direction of reflection can be
effectively controlled.
[0006] Though the prior art uses a resin coating to increase the
intensity of light scattering in a direction perpendicular to the
display screen, the manufacturing cost of the reflection
type/transflection type TFTLCD is quite expensive and the
manufacturing process is quite complex (with one more photomask
required). Indeed, how to reduce the manufacturing cost and
simplify the manufacturing process of the conventional reflection
type/transflection type TFTLCD is a major object of advancing the
development of the manufacturing technique of the existing display
device. The present invention can satisfy these needs.
SUMMARY OF THE INVENTION
[0007] An object of the present invention is to provide a
manufacturing process for a thin film transistor liquid crystal
display, comprising the steps of: (a) providing an insulating
substrate, (b) forming a thin film transistor the insulating
substrate and forming a transparent electrode on the thin film
transistor, wherein the transparent electrode is electrically
contacted with a source region and a drain region of the thin film
transistor, (c) forming a conducting layer on the transparent
electrode layer, and (d) etching the conducting layer to define a
curved structure with an inclination on the transparent
electrode.
[0008] Preferably, the angle of the inclination may be ranged from
3 to 20 degrees, and the curved structure may be shaped into an
awl-shaped structure or a conical structure.
[0009] Another object of the present invention is focused on the
provision of a manufacturing process for a thin film transistor
liquid crystal display, comprising the steps of: (a) providing an
insulating substrate, (b) forming a gate structure on a portion of
the insulating substrate, (c) forming an insulating layer on the
insulating substrate and the gate structure, (d) forming a first
semiconductor structure and a second semiconductor structure on the
insulating layer, (e) forming a conducting layer on the insulating
layer and the second semiconductor structure, (f) etching the
conducting layer to define a source region and a drain region and a
curved structure with an inclination on the insulating layer, and
(e) forming a transparent electrode on the curved structure,
wherein the transparent electrode is electrically contacted with a
source region and a drain region of the conducting layer.
[0010] A further object of the present invention is involved with a
thin film transistor liquid crystal display, including an
insulating substrate, a thin film transistor formed on the
insulating substrate, a transparent electrode formed on the
insulating substrate and the thin film transistor and electrically
contacted with a source region and a drain region -of the thin film
transistor, and a curved structure with an inclination formed on
the transparent electrode.
[0011] It is still an object of the present invention to provide a
thin film transistor liquid crystal display, including an
insulating substrate, a thin film transistor formed on the
insulating substrate, a curved structure with an inclination formed
on the insulating substrate, and a transparent electrode formed on
the curved structure.
[0012] Now the foregoing and other features and advantages of the
present invention will become more apparent through the following
embodiments with reference to the accompanying drawings,
wherein:
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIGS. 1(a) and 1(b) are cross-sectional views schematically
illustrating the reflection type/transflection type TFTLCD
according to the prior art;
[0014] FIGS. 2(a) to 2(h2) are cross-sectional views schematically
illustrating the manufacturing steps involved in the production of
TFTLCD according to a first preferred embodiment of the present
invention; and
[0015] FIGS. 3(a) to 3(g4) are cross-sectional views schematically
illustrating the manufacturing steps involved in the production of
TFTLCD according to a second preferred embodiment of the present
invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0016] The manufacturing steps involved in the production of the
TFTLCD according to a first preferred embodiment of the present
invention can be best understood in virtue of the following
descriptions and the cross-sectional views of FIGS. 2(a) to 2(h2).
Referring to FIG. 2(a), an insulating substrate 211 is provided and
a conducting layer (which can be formed from chromium, tungsten
molybdenum, tantalum, aluminum or copper) is formed onto the
insulating substrate 211, and a first photomask lithography and
etching process is performed define a gate structure 212 on the
insulating substrate 211. In FIG. 2(b), an insulating layer 233, a
first semiconductor layer 214 (which is commonly made of an
amorphous-silicon layer) and a second semiconductor layer 215
(which is commonly made of a highly-doped N+ amorphous-silicon
layer) are sequentially formed on the gate structure 212 and the
substrate 211. As shown in FIG. 2(c), a second photorask
lithography and etching process is performed to remove a portion of
the first semiconductor layer 214 and the second semiconductor
layer 215, so as to define a first semiconductor structure 216 and
a second semiconductor structure 217 on a portion of the insulating
layer 213. As shown in FIG. 2(d), a conducting layer 218 is
deposited onto the second semiconductor structure 217 and the
insulating layer 213. As shown in FIG. 2(e), a third photomask
lithography and etching process is performed to remove a portion of
the conducting layer 218 and the second semiconductor structure
217. An opening 219 exposing a portion of the surface of the first
semiconductor structure 216 is formed in the conducting layer 218,
and a source region and a drain region 220 are respectively defined
on the opposite sides of the opening 219. In FIG. 2(f), a
passivation film 221 (which is commonly made of silicon nitride) is
formed to cover the drain and source region 220, and a fourth
photomask lithography and etching process is performed to define a
contact window 222. Referring to FIG. 2(g), a transparent electrode
layer commonly made of indium-tin-oxide (ITO) is formed on the
passivation film 221, and a fifth photomask lithography and etching
process is performed to define a transparent pixel electrode 233.
FIGS. 2(h1) and 2(h2) respectively show that a conducting layer is
formed onto the transparent pixel electrode 233, and a sixth
photomask lithography and etching process is performed to define
awl-shaped conducting structures 224 and conical conducting
structures 225 on the transparent pixel electrode 223. With the
variation of the parameters of the concentration of the etch agent,
etching time, temperature and so on, awl-shaped conducting
structures 224 or conical conducting structures 225 that are of
different awl-like profiles may be formed on the transparent pixel
electrode 223. More Preferably, both of the awl-like conducting
structures 224 and 225 have an inclination of 3 to 20 degrees, and
thereby the light scattering angle can be adjusted
appropriately.
[0017] The formation steps of the TFTLCD according to a second
preferred embodiment of the present invention can be best
understood in virtue of the following descriptions and the
cross-sectional views of FIGS. 3(a) to 3(g4). Referring to FIG.
3(a), an insulating substrate 311 is provided and a conducting
layer (which can be formed from chromium, tungsten molybdenum,
tantalum, aluminum or copper) is formed on the insulating substrate
311, and a first photomask lithography and etching process is then
performed to define a gate structure 312 on the insulating
substrate 311. Next, as shown in FIG. 3(b), an insulating layer
313, a first semiconductor layer 314 (which is commonly made of an
amorphous-silicon layer) and a second semiconductor layer 315
(which is commonly made of a highly-doped N+ amorphous-silicon
layer) are sequentially formed on the gate structure 312 and the
substrate 31. As shown in FIG. 3(c), a second photomask lithography
and etching process is performed to remove a portion of the first
semiconductor layer 314 and the second semiconductor layer 315, so
as to define a first semiconductor structure 316 and a second
semiconductor structure 317 on a portion of the insulating layer
313. As shown in FIG. 3(d), a conducting layer 318 is deposited
onto the second semiconductor structure 317 and the insulating
layer 313. As shown in FIGS. 3(e1) and 3(e2), a third photomask
lithography and etching process is performed to remove a portion of
the conducting layer 318 and the second semiconductor structure
317. An opening 319 exposing a portion of the surface of the first
semiconductor structure 316 is formed in the conducting layer 318,
and a source region and a drain region 320 are respectively defined
on the opposite sides of the opening 319. In FIG. 3(e1), a fourth
photomask lithography and etching process is performed to define
awl-shaped conducting structures 3211 on the insulating layer 313.
In FIG. 3(e2), a fourth photomask lithography and etching process
is performed to define conical conducting structures 3212 on the
insulating layer 313. With the variation of the parameters of the
concentration of the etch agent, etching time, temperature and so
on, awl-shaped conducting structures 3211 or conical conducting
structures 3212 that are of different awl-like profiles may be
formed on the insulating layer 313. More preferably, both of the
awl-like conducting structures 224 and 225 have an inclination of 3
to 20 degrees, and thereby the light scattering angle can be
adjusted appropriately. FIGS. 3(f1) and 3(f2) respectively shows
that after the source and drain region 320 are defined, a
passivation film 321 (which is commonly made of silicon nitride) is
formed to cover the drain and source region 320, and a fifth
photomask lithography and etching process is performed to define a
contact window 322. FIGS. 3(g1) and 3(g2) respectively shows that
after a transparent electrode layer commonly maze of
indium-tin-oxide (ITO) is deposited onto the passivation film 321
and the awl-like conducting structures 3211 and 3212, a sixth
photomask lithography and etching process is performed to define a
transparent pixel electrode 3231 and 3232.
[0018] The formation of the awl-like conducting structures as
mentioned above can be further illustrated by the following
manufacturing steps to get a better understanding to the present
invention.
[0019] First, a double-layer metal film is deposited, for example,
a molybdenum-chromium alloy thin-film of a thickness of 200 nm is
deposited as the bottom layer, and an aluminum alloy thin-film of a
thickness of 50 nm is deposited on the molybdenum-chromium alloy
thin-film as a top layer. With the use of photomask to perform
exposure and development steps to define the pattern of the area
that is to be reserved, an etching step is then performed with a
mixed-acid based etch solution, for example, the mixture of
phosphoric acid (H.sub.3PO.sub.4), nitric acid (HNO.sub.3) and/or
acetic acid (CH.sub.3CCOH) to etch the double-layer metal film, so
as to define awl-like conducting structures with an inclination.
The angle of the inclination may be controlled by adjusting the
over-etching time in cooperation with the photomask of an
appropriate line width (about 3 .mu.m to 10 .mu.m), and further
awl-shaped or conical conducting structures can be created as
desired.
[0020] A preferable aspect of the present invention is to provide a
reflection type/transflection type TFTLCD. Therefore, the
transparent electrode layer made of ITO can be served for a third
conducting layer. FIGS. 3(g3) and 3(g4) respectively show that
after the third conducting layer is deposited onto the passivation
film 321 and the awl-like conducting structures (3211,3212), a
sixth photomask lithography and etching process is performed to
define a pixel area constituted by transparent electrode
(3233,3234).
[0021] In conclusion with the above statements, it can be readily
understood that the present invention is superior to the prior art
in terms of the inclusion of the awl-like conducting structures
with an inclination. Because the awl-like conducting structures is
provided with an inclination, the magnitude of the light reflecting
angle can be adjusted and the direction of reflection can be
controlled efficiently. More specifically, with the introduction of
the present invention, the manufacturing process of the thin film
transistor liquid crystal display can be simplified by eliminating
one photomask lithography and etching process compared with the
prior art, and the manufacturing cost can be slashed due to the
removal of the costly resin coating.
[0022] Those of skill in the art will soon recognize that these and
other modifications can be made within the spirit and scope of the
present invention as further defined in the appended claims.
* * * * *