U.S. patent application number 16/178606 was filed with the patent office on 2019-02-28 for manufacturing method of pixel structure.
This patent application is currently assigned to Chunghwa Picture Tubes, LTD.. The applicant listed for this patent is Chunghwa Picture Tubes, LTD.. Invention is credited to Hsi-Ming Chang, Yen-Yu Huang.
Application Number | 20190067335 16/178606 |
Document ID | / |
Family ID | 58157837 |
Filed Date | 2019-02-28 |
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United States Patent
Application |
20190067335 |
Kind Code |
A1 |
Chang; Hsi-Ming ; et
al. |
February 28, 2019 |
MANUFACTURING METHOD OF PIXEL STRUCTURE
Abstract
A method for manufacturing a pixel structure is provided. A
patterned semiconductor material layer, an insulation material
layer, and a gate electrode material layer are formed in sequence
on a substrate to form a stacked structure. A patterned photoresist
layer is formed on the stacked structure by using a photomask. A
portion of the stacked structure is removed to pattern the
patterned semiconductor material layer into a patterned
semiconductor layer by using the patterned photoresist layer as a
mask. Another portion of the stacked structure is etched by using a
portion of the patterned photoresist layer as a mask until a
portion of the semiconductor layer in the stacked structure is
exposed. Then, an exposed portion of the semiconductor layer is
modified to increase a conductivity of the exposed portion of the
semiconductor layer. Finally, the patterned photoresist layer is
removed. A pixel structure manufactured by the method is
provided.
Inventors: |
Chang; Hsi-Ming; (Taoyuan
City, TW) ; Huang; Yen-Yu; (Taoyuan City,
TW) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
Chunghwa Picture Tubes, LTD. |
Taoyuan City |
|
TW |
|
|
Assignee: |
Chunghwa Picture Tubes,
LTD.
Taoyuan City
TW
|
Family ID: |
58157837 |
Appl. No.: |
16/178606 |
Filed: |
November 2, 2018 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
14829179 |
Aug 18, 2015 |
10153302 |
|
|
16178606 |
|
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Current U.S.
Class: |
1/1 |
Current CPC
Class: |
H01L 27/127 20130101;
H01L 27/1248 20130101; H01L 27/124 20130101; H01L 27/1225 20130101;
H01L 27/1288 20130101; H01L 27/1262 20130101 |
International
Class: |
H01L 27/12 20060101
H01L027/12 |
Claims
1. A manufacturing method of a pixel structure, the method
comprising: forming a patterned semiconductor material layer, an
insulation material layer, and a gate electrode material layer in
sequence on a substrate to form a stacked structure; forming a
patterned photoresist layer on the stacked structure by using a
photomask, wherein the patterned photoresist layer comprises a
first thickness portion covering a first portion of the stacked
structure and a second thickness portion covering a second portion
of the stacked structure, and the patterned photoresist layer
exposes a third portion of the stacked structure; removing the
third portion of the stacked structure to pattern the patterned
semiconductor material layer into a patterned semiconductor layer
by using the patterned photoresist layer as a mask; removing the
first thickness portion of the patterned photoresist layer and
thinning the second thickness portion of the patterned photoresist
layer to expose the first portion of the stacked structure
previously covered by the first thickness portion of the patterned
photoresist layer; etching the first portion of the stacked
structure by using the thinned second thickness portion of the
patterned photoresist layer as a mask until an exposed portion of
the patterned semiconductor layer in the first portion of the
stacked structure is exposed, wherein the gate electrode material
layer is patterned into a gate electrode layer, and the insulation
material layer is patterned into an insulation layer having a shape
substantially conformal to the gate electrode layer and covering a
covered portion of the patterned semiconductor layer; modifying the
exposed portion of the patterned semiconductor layer to increase a
conductivity of the exposed portion of the patterned semiconductor
layer; and removing the thinned second thickness portion of the
patterned photoresist layer, wherein the covered portion of the
patterned semiconductor layer comprises a channel, the exposed
portion of the patterned semiconductor layer comprises a source and
a drain, the gate electrode layer comprises a gate above the
channel, and the gate, the channel, the source and the drain form a
thin film transistor structure.
2. The method as claimed in claim 1, further comprising forming a
patterned metal layer on the substrate prior to forming the stacked
structure, wherein the patterned metal layer comprises a data line
electrically connected to the source.
3. The method as claimed in claim 2, wherein the patterned
semiconductor material layer has an opening exposing a portion of
the data line and the patterned semiconductor layer patterned from
the patterned semiconductor material layer comprises a
semiconductor portion and has a separating gap corresponding to the
opening, such that the insulation layer patterned from the
insulation material layer comprises an insulation portion filling
the separating gap and contacting the portion of the data line and
the semiconductor portion is electrically insulating to the data
line.
4. The method as claimed in claim 1, wherein the removing the first
thickness portion of the patterned photoresist layer and the
thinning the second thickness portion of the patterned photoresist
layer comprises performing an ashing process.
5. The method as claimed in claim 1, wherein the forming the
patterned photoresist layer on the stacked structure comprises
using one half-tone photomask or one gray-tone photomask to form
the first thickness portion and the second thickness portion.
6. The method as claimed in claim 1, wherein the modifying the
exposed portion of the patterned semiconductor layer comprises
performing a plasma treatment, an ion implanting, or a combination
thereof.
7. The method as claimed in claim 6, wherein the plasma treatment
uses hydrogen gas as a processing gas.
8. The method as claimed in claim 1, wherein the removing the
second thickness portion comprises performing a stripping
process.
9. The method as claimed in claim 1, further comprising forming a
pixel electrode electrically connected to the drain.
10. The method as claimed in claim 9, wherein the formation of the
pixel electrode is simultaneous to the formation of the source and
the drain.
11. The method as claimed in claim 9, wherein the pixel electrode
is formed by modifying the exposed portion of the patterned
semiconductor layer.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a divisional application of U.S.
application Ser. No. 14/829,179, filed on Aug. 18, 2015, now
allowed. The entirety of the above-mentioned patent applications is
hereby incorporated by reference herein and made a part of this
specification.
BACKGROUND
Field of the Invention
[0002] The invention relates to a pixel structure and a
manufacturing method thereof. In particular, the invention relates
to a pixel structure with a patterned oxide semiconductor
layer.
Description of Related Art
[0003] In general, the conventional manufacturing process of a
pixel structure having an oxide semiconductor layer substantially
involves six masking steps. With the first masking step, a gate
electrode is formed on a substrate. Then, a gate insulating layer
is comprehensively formed on the substrate for covering the gate
electrode. Next, with the second masking step, an oxide
semiconductor layer is formed on the gate insulating layer above
the gate electrode. Furthermore, with the third masking step, an
etching stop layer is formed on a portion of the oxide
semiconductor layer. Afterward, a metal layer is formed on the
etching stop layer; and with the fourth masking step, a source
electrode and a drain electrode, which are electrically insulated
with each other, are separately defined on two sides of the etching
stop layer. Then, an insulating layer is formed on the substrate
for covering the source electrode and the drain electrode. After
that, with the fifth masking step, a contact window is formed on
the insulating layer in order to expose the drain electrode.
Finally, with the sixth masking step, a pixel electrode is formed
on the substrate, and this pixel electrode fills up the contact
window and is electrically connected with the drain electrode. At
this point, the manufacturing of the pixel structure having the
oxide semiconductor layer is completed. Nevertheless, the
abovementioned manufacturing process of the pixel structure is
complicated, and has high production costs.
SUMMARY OF THE INVENTION
[0004] The invention is to provide a pixel structure and a
manufacturing method thereof, capable of reducing production costs
and simplifying the manufacturing process by reducing the number of
masks.
[0005] The invention provides a method of forming a pixel
structure. The method includes the following steps. A patterned
semiconductor material layer, an insulation material layer, and a
gate electrode material layer are formed in sequence on a substrate
to form a stacked structure. Next, a patterned photoresist layer is
formed on the stacked structure by using a photomask. The patterned
photoresist layer comprises a first thickness portion covering a
first portion of the stacked structure and a second thickness
portion covering a second portion of the stacked structure, and the
patterned photoresist layer exposes a third portion of the stacked
structure. The third portion of the stacked structure is removed to
pattern the patterned semiconductor material layer into a patterned
semiconductor layer by using the patterned photoresist layer as a
mask. The first thickness portion of the patterned photoresist
layer is then removed and the second thickness portion of the
patterned photoresist layer is thinned to expose the first portion
of the stacked structure previously covered by the first thickness
portion of the patterned photoresist layer. Next, the first portion
of the stacked structure is etched by using the thinned second
thickness portion of the patterned photoresist layer as a mask
until an exposed portion of the patterned semiconductor layer in
the first portion of the stacked structure is exposed. The gate
electrode material layer is patterned into a gate electrode layer,
and the insulation material layer is patterned into an insulation
layer having a shape substantially conformal to the gate electrode
layer and covering a covered portion of the patterned semiconductor
layer. Then, the exposed portion of the patterned semiconductor
layer is modified to increase a conductivity of the exposed portion
of the patterned semiconductor layer. The thinned second thickness
portion of the patterned photoresist layer is then removed. The
covered portion of the patterned semiconductor layer includes a
channel, and the exposed portion of the patterned semiconductor
layer includes a source and a drain. The gate electrode layer
includes a gate above the channel, and the gate, the channel, the
source and the drain form a thin film transistor structure.
[0006] In an embodiment of the invention, the method further
includes forming a patterned metal layer on the substrate prior to
forming the stacked structure. The patterned metal layer includes a
data line electrically connected to the source.
[0007] In an embodiment of the invention, the patterned
semiconductor material layer has an opening exposing a portion of
the data line and the patterned semiconductor layer patterned from
the patterned semiconductor material layer includes a semiconductor
portion and has a separating gap corresponding to the opening, such
that the insulation layer patterned from the insulation material
layer has a insulation portion filling the separating gap and
contacting the portion of the data line and the semiconductor
portion is electrically insulating to the data line.
[0008] In an embodiment of the invention, removing the first
thickness portion of the patterned photoresist layer and the
thinning the second thickness portion of the patterned photoresist
layer includes performing an ashing process.
[0009] In an embodiment of the invention, the forming the patterned
photoresist layer on the stacked structure includes using one
half-tone photomask or one gray-tone photomask to form the first
thickness portion and the second thickness portion.
[0010] In an embodiment of the invention, modifying the exposed
portion of the patterned semiconductor layer includes performing a
plasma treatment, an ion implanting, or a combination thereof.
[0011] In an embodiment of the invention, a processing gas of the
plasma treatment includes hydrogen gas.
[0012] In an embodiment of the invention, removing the second
thickness portion includes performing a stripping process.
[0013] In an embodiment of the invention, the method further
includes forming a pixel electrode electrically connected to the
drain.
[0014] In an embodiment of the invention, the formation of the
pixel electrode is simultaneous to the formation of the source and
the drain.
[0015] In an embodiment of the invention, the pixel electrode is
formed by modifying the exposed portion of the patterned
semiconductor layer.
[0016] The invention further provides a pixel structure. The pixel
structure includes a pixel electrode, disposed on a substrate, a
thin film transistor structure, and an insulation layer. The thin
film transistor structure is disposed on the substrate and
connected to the pixel electrode. The thin film transistor
structure includes a source, a drain and a channel formed by a
patterned semiconductor layer and a gate formed by a gate electrode
layer. The source and the drain are located on two opposite sides
of the channel, and the gate is located above the channel. The
insulation layer is interposed between the patterned semiconductor
layer and the gate electrode layer and has a shape substantially
conformal to the gate electrode layer. The insulation layer covers
an covered portion of the patterned semiconductor layer to form the
channel and exposes an exposed portion of the patterned
semiconductor layer to form the source and the drain.
[0017] In an embodiment of the invention, a material of the
patterned semiconductor layer includes an oxide semiconductor
material.
[0018] In an embodiment of the invention, the covered portion of
the patterned semiconductor layer has a first conductivity type and
the exposed portion of the patterned semiconductor layer has a
second conductivity type more conductive than the first
conductivity type.
[0019] In an embodiment of the invention, the exposed portion of
the patterned semiconductor layer further includes the pixel
electrode.
[0020] In an embodiment of the invention, the pixel structure
further includes a data line disposed on the substrate, located
between the patterned semiconductor layer and the substrate, and
electrically connected to the source of the thin film transistor
structure.
[0021] In an embodiment of the invention, the gate electrode layer
further includes a gate line electrically connected to the gate of
the thin film transistor structure. The insulation layer includes
an insulation portion underlying the gate line. The patterned
semiconductor layer further includes a semiconductor portion
underlying the gate line, and the gate line, the insulation portion
and the semiconductor portion form a gate line structure crossing
over the data line.
[0022] In an embodiment of the invention, the patterned
semiconductor layer has a separating gap exposing a portion of the
data line, and the insulation portion fills the separating gap and
contacts the portion of the data line. In addition, the
semiconductor portion is electrically insulating to the data
line.
[0023] In an embodiment of the invention, a portion of the source
is in direct contact with the data line to electrically connect to
the data line.
[0024] In an embodiment of the invention, the pixel structure
further includes a patterned metal portion disposed on the
substrate, located and electrically connected between the drain and
the pixel electrode. A material of the patterned metal portion and
the data line is the same.
[0025] Based on the above, in the manufacturing process of the
pixel structure of the invention, the patterned photoresist layer
is patterned to have a first thickness portion and a second
thickness portion by using a photomask, and the following processes
of forming the pixel structure use the patterned photoresist layer
as a mask for forming multiple elements, such as the channel, the
source, the drain, the gate and the gate insulation layer.
Therefore, this allows the manufacture of the pixel structure of
the invention to reduce the amount of photomasks required. Thus,
the manufacturing cost of the pixel structure of the invention can
be effectively lowered. Furthermore, in the pixel structure, the
source and drain are electrically contacted with the channel
without contact holes. In addition, the drain is electrically
contacted with the pixel electrode without contact holes. The pixel
structure according to the embodiment of the present invention has
an improved resolution or aperture ratio. In addition, not
requiring contact holes also saves space in the thin film
transistor layout that utilizes the pixel structure.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] The accompanying drawings are included to provide a further
understanding of the invention, and are incorporated in and
constitute a part of this specification. The drawings illustrate
embodiments of the invention and, together with the description,
serve to explain the principles of the invention.
[0027] FIG. 1A to FIG. 12A are schematic top views illustrating the
manufacture process of a pixel structure according to an embodiment
of the invention.
[0028] FIG. 1B to FIG. 12B are schematic cross-sectional views
respectively taken along line A-A' in the corresponding FIG. 1A to
FIG. 12A.
[0029] FIG. 12C is a schematic cross-sectional view taken along
line B-B' in the corresponding FIG. 12A.
[0030] FIG. 13A to FIG. 24A are schematic top views illustrating
the manufacture process of a pixel structure according to another
embodiment of the invention.
[0031] FIG. 13B to FIG. 24B are schematic cross-sectional views
respectively taken along line A-A' in the corresponding FIG. 13A to
FIG. 24A.
[0032] FIG. 24C is a schematic cross-sectional view taken along
line B-B' in the corresponding FIG. 24A.
DESCRIPTION OF THE EMBODIMENTS
[0033] Reference will now be made in detail to the present
preferred embodiments of the invention, examples of which are
illustrated in the accompanying drawings. Wherever possible, the
same reference numbers are used in the drawings and the description
to refer to the same or like parts.
[0034] FIG. 1A to FIG. 12A are schematic top views illustrating the
manufacture process of a pixel structure according to an embodiment
of the invention. FIG. 1B to FIG. 12B are schematic cross-sectional
views respectively taken along line A-A' in the corresponding FIG.
1A to FIG. 12A. It should be noted that in FIG. 1A to FIG. 12A, if
a boundary of a layer substantially overlaps with another layer,
the schematic top views only label the top most layer. Thus, FIG.
1A to FIG. 12A have omitted the references for some of the
components. Please refer to the corresponding schematic
cross-sectional views (i.e., FIG. 1B to FIG. 12B) at the same time.
The following uses FIG. 1A to FIG. 12A and FIG. 1B to FIG. 12B to
describe the manufacture process of the pixel structure of an
embodiment of the invention.
[0035] Referring to FIG. 1A and FIG. 1B, a metal layer (not shown)
is first formed on a substrate 110. Next, the metal layer is
patterned to form a patterned metal layer 120 on the substrate 110.
The patterned metal layer includes a first metal portion 120a, a
second metal portion 120b, and a data line 120c. The first metal
portion 120a branches off of the data line 120c. A material of the
patterned metal layer 120 is, for example, molybdenum, aluminum,
titanium, indium tin oxide, or a combination thereof. However, the
invention is not limited thereto.
[0036] Referring to FIG. 2A and FIG. 2B, a patterned semiconductor
material layer 130 is formed on the substrate 110. Particularly,
the patterned semiconductor material layer 130 has an opening 130A
exposing a portion of the data line 120c. A material of the
patterned semiconductor material layer 130 is an oxide
semiconductor material. For example, the material of the patterned
semiconductor material layer 130 may be indium gallium zinc oxide,
indium zinc oxide, indium gallium oxide, zinc oxide, tin oxide,
gallium zinc oxide, zinc tin oxide, or indium tin oxide. However,
the invention is not limited thereto. In addition, the opening 130A
can be formed by performing a lithography-etching process.
[0037] Referring to FIG. 3A and FIG. 3B, an insulation material
layer 140 is formed on the patterned semiconductor material layer
130. A material of the insulation material layer 140 is for
example, silicon dioxide. However, the invention is not limited
thereto.
[0038] Referring to FIG. 4A and FIG. 4B, a gate electrode material
layer 150 is formed on the insulation material layer 140. A
material of the gate electrode material layer 150 is for example,
molybdenum, aluminum, titanium, or a combination thereof. However,
the invention is not limited thereto.
[0039] Thus, it can be seen that the patterned semiconductor
material layer 130, the insulation material layer 140, and the gate
electrode material layer 150 are formed in sequence on the
substrate 110 to form a stacked structure 152.
[0040] Referring to FIG. 5A and FIG. 5B, a photoresist layer 160 is
formed on the gate electrode material layer 150 by using a
photosensitive material.
[0041] Referring to FIG. 6A and FIG. 6B, a photomask 162 is used to
pattern the photoresist layer 160. The photomask 162 includes a
first mask pattern 162a, a second mask pattern 162b, and a third
mask pattern 162c with different transparencies. The transparency
of the second mask pattern 162b is, for example, between the
transparencies of the first mask pattern 162a and the third mask
pattern 162c. In further detail, the first mask pattern 162a is,
for example, completely transparent, the third mask pattern 162c
is, for example, not transparent, and the second mask pattern 162b
has a transparency between the first mask pattern 162a and the
third mask pattern 162c. The photomask 162 may be a half-tone
photomask or a gray-tone photomask. However, the invention is not
limited thereto. Any suitable type of photomask to pattern the
photoresist layer 160 can be utilized.
[0042] Referring to FIG. 7A and FIG. 7B, the photoresist layer 160
is patterned to form a patterned photoresist layer 164. The
patterned photoresist layer 164 includes a first thickness portion
164a and a second thickness portion 164b. The first thickness
portion 164a corresponds to the second mask pattern 162b of the
photomask 162 and covers a first portion 152a of the stacked
structure 152. The second thickness portion 164b corresponds to the
third mask pattern 162c of the photomask 162 and covers a second
portion 152b of the stacked structure 152. A third portion 152c of
the stacked structure 152 is exposed by the patterned photoresist
layer 164, wherein the third portion 152c of the stacked structure
152 corresponds to the first mask pattern 162a of the photomask
162. In the present embodiment, owing to transparency difference of
the second mask pattern 162b and the third mask pattern 162c, the
second thickness portion 164b is thicker than the first thickness
portion 164a.
[0043] Referring to FIG. 8A and FIG. 8B, the third portion 152c of
the stacked structure 152 is removed to pattern the patterned
semiconductor material layer 130 into a patterned semiconductor
layer 132 by using the patterned photoresist layer 164 as a mask.
The patterned semiconductor layer 132 has the same shape as the
first thickness portion 164a and the second thickness portion 164b
of the patterned photoresist layer 164. The third portion 152c of
the stacked structure 152 is removed by etching from the gate
electrode material layer 150 until the patterned metal layer 120 is
exposed. Thus, parts of the first metal portion 120a, the second
metal portion 120b, and the data line 120c are exposed.
[0044] Referring to FIG. 9A and FIG. 9B, the first thickness
portion 164a of the patterned photoresist layer 164 is then removed
and the second thickness portion 164b of the patterned photoresist
layer 164 is thinned to expose the first portion 152a of the
stacked structure 152 previously covered by the first thickness
portion 164a of the patterned photoresist layer 164. In the
embodiment, an ashing process is performed to remove the first
thickness portion 164a of the patterned photoresist layer 164 and
thin the second thickness portion 164b of the patterned photoresist
layer 164.
[0045] Referring to FIG. 10A and FIG. 10B, the first portion 152a
of the stacked structure 152 is etched by using the thinned second
thickness portion 164b of the patterned photoresist layer 164 as a
mask until an exposed portion 132J of the patterned semiconductor
layer 132 in the first portion 152a of the stacked structure 152 is
exposed. The gate electrode material layer 150 is patterned into a
gate electrode layer 154, and the insulation material layer 140 is
patterned into an insulation layer 142 having a shape substantially
conformal to the gate electrode layer 154 and covering a covered
portion 1321 of the patterned semiconductor layer 132.
[0046] Referring to FIG. 11A and FIG. 11B, the exposed portion 132J
of the patterned semiconductor layer 132 is then modified to
increase a conductivity of the exposed portion 132J of the
patterned semiconductor layer 132. The process for modifying the
exposed portion 132J of the patterned semiconductor layer 132
includes performing a plasma treatment, an ion implanting, or a
combination thereof. Particularly, in the plasma treatment, a
processing gas includes hydrogen gas. However, the invention is not
limited thereto. Other suitable method of modifying the exposed
portion 132J of the patterned semiconductor layer 132 can be
performed for increasing the conductivity of the exposed portion
132J of the patterned semiconductor layer 132.
[0047] By modifying the exposed portion 132J of the patterned
semiconductor layer 132 by the insulation layer 142 to increase
conductivity, the modified portion of the patterned semiconductor
layer 132 includes and forms a pixel electrode 132a, a drain 132b,
and a source 132c. The pixel electrode 132a is electrically
connected to the drain 132b through the second metal portion 120b.
That is to say the pixel electrode 132a is electrically connected
to the second metal portion 120b, and the second metal portion 120b
is electrically connected to the drain 132b.
[0048] In the embodiment, the pixel electrode 132a is formed
simultaneously with the formation of the source 132c and the drain
132b by using the same film layer. In addition, the covered portion
1321 of the patterned semiconductor layer 132, that was covered by
the insulation layer 142 and not modified to increase conductivity,
forms a channel 132d.
[0049] Referring to FIG. 12A and FIG. 12B, the thinned second
thickness portion 164b of the patterned photoresist layer 164 is
then removed. The process for removing the second thickness portion
164b includes performing a stripping process. However, the
invention is not limited thereto. Other suitable method of removing
the second thickness portion 164b can also be selected. After
removing the second thickness portion 164b, the gate electrode
layer 154 is exposed, and a pixel structure 100 of the embodiment
is completely manufactured. In the present embodiment, the gate
electrode layer 154 includes a gate 154a above the channel 132d,
and a gate line 154b electrically connected to the gate 154a. The
gate 154a, the channel 132d, the source 132c and the drain 132b
form a thin film transistor structure 134. Based on the method
described above, it can be seen that the thin film transistor
structure 134 is self-aligned during formation, wherein the channel
132d and the gate 154a are defined by using the thinned second
thickness portion 164b of the patterned photoresist layer 164.
Thus, the thin film transistor structure 134 is a self-aligned thin
film transistor structure. Particularly, in the present embodiment,
the channel 132d, the source 132c, the drain 132b and the gate 154a
are formed by using the same patterned photoresist layer 160 and
the patterned photoresist layer 160 is formed by using one
photomask. Therefore, the required amount of photomask for forming
the thin film transistor structure 134 is reduced for saving the
manufacture cost.
[0050] FIG. 12C is a schematic cross-sectional view taken along
line B-B' in the corresponding FIG. 12A. Referring to FIG. 12A,
FIG. 12B, and FIG. 12C, the pixel structure 100 includes the pixel
electrode 132a disposed on a substrate 110, the thin film
transistor structure 134, and the insulation layer 142. The thin
film transistor structure 134 is disposed on the substrate 110 and
connected to the pixel electrode 132a. The thin film transistor
structure 134 includes the source 132c, the drain 132b and the
channel 132d formed by the same patterned semiconductor layer 132
and the gate 154a formed by the gate electrode layer 154. The
source 132c and the drain 132b are located at two opposite sides of
the channel 132d, and the gate 154a is located above the channel
132d. The insulation layer 142 is interposed between the patterned
semiconductor layer 132 and the gate electrode layer 154 and has a
shape substantially conformal to the gate electrode layer 154. The
insulation layer 142 covers a portion of the patterned
semiconductor layer 132 to form the channel 132d and exposes
another portion of the patterned semiconductor layer 132 to form
the source 132c and the drain 132b.
[0051] According to the step depicted in FIG. 11A and FIG. 11B, the
covered portion 1321 of the patterned semiconductor layer 132 has a
first conductivity type and the exposed portion 132J of the
patterned semiconductor layer 132 has a second conductivity type
more conductive than the first conductivity type. Therefore, the
exposed portion 132J of the patterned semiconductor layer 132 can
form the source 132c, the drain 132b and the pixel electrode 132a
which are the elements predetermined to be electrically
conductive.
[0052] For transmitting the electric signals, the pixel structure
100 further includes the data line 120c disposed on the substrate
110, and electrically connected to the source 132c of the thin film
transistor structure 134, wherein the first metal portion 120a of
the data line 120c is located between the semiconductor layer 132
and the substrate 110. In addition, the gate electrode layer 154
further includes the gate line 154b electrically connected to the
gate 154a of the thin film transistor structure 134. The gate line
154b and the data line 120c extends in different directions for
respectively transmitting a control signal to the gate 154a and
transmitting a data signal to the source 132c. Therefore, the thin
film transistor structure 134 can be turned on by the control
signal and the data signal can be transmitted to the pixel
electrode 132a through the turned-on thin film transistor structure
134.
[0053] In the present embodiment, the gate line 154b is formed by
using the same method of forming the gate 154a. Therefore, the
insulation layer 142 includes an insulation portion 142a underlying
the gate line 154b. The insulation portion 142a conforms in shape
to the gate line 154b. The patterned semiconductor layer 132
further includes a semiconductor portion 132e underlying the gate
line 154b and has a separating gap SG corresponding to the opening
130A shown in FIG. 2A and exposing a portion of the data line 120c.
The semiconductor portion 132e partially conforms in shape to the
gate line 154b. The gate line 154b, the insulation portion 142a and
the semiconductor portion 132e form a gate line structure 156,
where the gate line 154b and the insulation portion 142a of the
gate line structure 156 cross over the data line 120c at the
separating gap SG such that the semiconductor portion 132e is not
in contact with the data line 120c and the insulation portion 142a
of the insulation layer 142 fills in the separating gap SG and
contacts the data line 120c for isolating the data line 120c from
the gate line 154b. In other words, the semiconductor portion 132e
of the gate line structure 156 is electrically insulating to the
data line 120c so that a short circuit would not generate between
the semiconductor portion 132e and the data line 120c.
[0054] In the embodiment, a portion of the source 132c is in direct
contact with the data line 120c by being in direct contact with the
first metal portion 120a that branches off of the data line 120c,
to electrically connect to the data line 120c. In addition, the
pixel structure 100 further includes the second metal portion 120b
disposed on the substrate 110, located and electrically connected
between the drain 132b and the pixel electrode 132a. A material of
the second metal portion 120b and the data line 120c is the same.
However, in an alternative embodiment, the first metal portion 120a
and the second metal portion 120b can be selectively omitted.
[0055] FIG. 13A to FIG. 24A are schematic top views illustrating
the manufacture process of a pixel structure according to another
embodiment of the invention. FIG. 13B to FIG. 24B are schematic
cross-sectional views respectively taken along line A-A' in the
corresponding FIG. 13A to FIG. 24A. It should be noted that in FIG.
13A to FIG. 24A, if a boundary of a layer substantially overlaps
with another layer, the schematic top views only label the top most
layer. Thus, FIG. 13A to FIG. 24A have omitted the references for
some of the components. Please refer to the corresponding schematic
cross-sectional views (i.e., FIG. 13B to FIG. 24B) at the same
time. The following uses FIG. 13A to FIG. 24A and FIG. 13B to FIG.
24B to describe the manufacturing process of the pixel structure of
another embodiment of the invention.
[0056] The difference between the embodiment of FIG. 13A to FIG.
24A, FIG. 13B to FIG. 24B, and FIG. 24C and the embodiment of FIG.
1A to FIG. 12A, FIG. 1B to FIG. 12B, and FIG. 12C, is that the
second metal portion 120b is not included in the embodiment of FIG.
13A to FIG. 24A, FIG. 13B to FIG. 24B, and FIG. 24C. Similar
elements will use the same names, and processes that are the same
both embodiments will not be repeated herein. The materials used
are also similar in both embodiments, and the description will not
be repeated herein.
[0057] Referring to FIG. 13A and FIG. 13B, a metal layer (not
shown) is first formed on a substrate 210. Next, the metal layer is
patterned to form a patterned metal layer 220 on the substrate 210.
The patterned metal layer includes a first metal portion 220a and a
data line 220c. The first metal portion 220a branches off of the
data line 220c.
[0058] Referring to FIG. 14A and FIG. 14B, a patterned
semiconductor material layer 230 is formed on the substrate 210.
Particularly, the patterned semiconductor material layer 230 has an
opening 230A exposing a portion of the data line 220c. Referring to
FIG. 15A and FIG. 15B, an insulation material layer 240 is formed
on the patterned semiconductor material layer 230. Referring to
FIG. 16A and FIG. 16B, a gate electrode material layer 250 is
formed on the insulation material layer 240. Thus, it can be seen
that the patterned semiconductor material layer 230, the insulation
material layer 240, and the gate electrode material layer 250 are
formed in sequence on the substrate 210 to form a stacked structure
252.
[0059] Referring to FIG. 17A and FIG. 17B, a photoresist layer 260
is formed on the gate electrode material layer 250 by using a
photosensitive material. Referring to FIG. 18A and FIG. 18B, a
photomask 262 is used to pattern the photoresist layer 260. The
photomask 262 includes a first mask pattern 262a, a second mask
pattern 262b, and a third mask pattern 262c with different
transparencies. The description of the photomask 262 is similar to
the photomask 162, and will not be repeated herein.
[0060] Referring to FIG. 19A and FIG. 19B, the photoresist layer
260 is patterned to form a patterned photoresist layer 264. The
patterned photoresist layer 264 includes a first thickness portion
264a and a second thickness portion 264b. The first thickness
portion 264a corresponds to the second mask pattern 262b of the
photomask 262 and covers a first portion 252a of the stacked
structure 252. The second thickness portion 264b corresponds to the
third mask pattern 262c of the photomask 262 and covers a second
portion 252b of the stacked structure 252. A third portion 252c of
the stacked structure 252 is exposed by the patterned photoresist
layer 264. The third portion 252c of the stacked structure 252 that
is exposed by the patterned photoresist layer 264 corresponds to
the first mask pattern 262a of the photomask 262. In the present
embodiment, owing to transparency difference of the second mask
pattern 262b and the third mask pattern 262c, the second thickness
portion 264b is thicker than the first thickness portion 264a.
[0061] Referring to FIG. 20A and FIG. 20B, the third portion 252c
of the stacked structure 252 is removed to pattern the patterned
semiconductor material layer 230 into a patterned semiconductor
layer 232 by using the patterned photoresist layer 264 as a mask.
The patterned semiconductor layer 232 has the same shape as the
first thickness portion 264a and the second thickness portion 264b
of the patterned photoresist layer 264 in the top view as shown in
FIG. 20A. The third portion 252c of the stacked structure 252 is
removed by etching from the gate electrode material layer 250 until
the patterned metal layer 220 is exposed. Thus, parts of the first
metal portion 220a and the data line 220c are exposed.
[0062] Referring to FIG. 21A and FIG. 21B, the first thickness
portion 264a of the patterned photoresist layer 264 is then removed
and the second thickness portion 264b of the patterned photoresist
layer 264 is thinned to expose the first portion 252a of the
stacked structure 252 previously covered by the first thickness
portion 264a of the patterned photoresist layer 264. In the
embodiment, an ashing process is performed to remove the first
thickness portion 264a of the patterned photoresist layer 264 and
thin of the second thickness portion 264b of the patterned
photoresist layer 264.
[0063] Referring to FIG. 22A and FIG. 22B, the first portion 252a
of the stacked structure 252 is etched by using the thinned second
thickness portion 264b of the patterned photoresist layer 264 as a
mask until an exposed portion 232J of the patterned semiconductor
layer 232 in the first portion 252a of the stacked structure 252 is
exposed. The gate electrode material layer 250 is patterned into a
gate electrode layer 254, and the insulation material layer 240 is
patterned into an insulation layer 242 having a shape substantially
conformal to the gate electrode layer 254 and covering a covered
portion 2321 of the patterned semiconductor layer 232.
[0064] Referring to FIG. 23A and FIG. 23B, the exposed portion 232J
of the patterned semiconductor layer 232 is then modified to
increase a conductivity of the exposed portion 232J of the
patterned semiconductor layer 232. This step is similar to the
description of the step in FIG. 11A and FIG. 11B, and will not be
repeated herein.
[0065] By modifying the exposed portion 232J of the patterned
semiconductor layer 232 exposed by the insulation layer 242 to
increase conductivity, the modified exposed portion 232J of the
patterned semiconductor layer 232 includes and forms a pixel
electrode 232a, a drain 232b, and a source 232c. The pixel
electrode 232a is electrically connected to the drain 232b. In the
embodiment, there is no a metal portion to electrically connect the
pixel electrode 232a and the drain 232b. Rather, the pixel
electrode 232a and the drain 232b are of the same patterned
semiconductor layer 232, and branch off of each other to be in
direct contact and electrically connected.
[0066] In the embodiment, the pixel electrode 232a is formed
simultaneously with the formation of the source 232c and the drain
232b by using the same film layer. In addition, the covered portion
2321 of the patterned semiconductor layer 232 covered by the
insulation layer 242 that was not modified to increase conductivity
forms a channel 232d. Accordingly, in the present embodiment, the
pixel electrode 232a, the source 232c, the drain 232b and the
channel 232d can be formed by using the same film layer, the
patterned semiconductor material layer 230.
[0067] Referring to FIG. 24A and FIG. 24B, the thinned second
thickness portion 264b of the patterned photoresist layer 264 is
then removed. The process for removing the second thickness portion
264b includes performing a stripping process. However, the
invention is not limited thereto. Any suitable method of removing
the second thickness portion 264b can be used. After removing the
second thickness portion 264b, the gate electrode layer 254 is
exposed, and a pixel structure 200 of the embodiment is completely
manufactured. In the present embodiment, the gate electrode layer
254 includes a gate 254a above the channel 232d, and a gate line
254b electrically connected to the gate 254a. The gate 254a, the
channel 232d, the source 232c and the drain 232b form a thin film
transistor structure 234. Based on the method described above, it
can be seen that the thin film transistor structure 234 is
self-aligned during formation, wherein the channel 232d and the
gate 254a are defined by using the thinned second thickness portion
264b of the patterned photoresist layer 264. Thus, the thin film
transistor structure 234 is a self-aligned thin film transistor
structure. Particularly, in the present embodiment, the channel
232d, the source 232c, the drain 232b and the gate 254a are formed
by using the same patterned photoresist layer 260 and the patterned
photoresist layer 260 is formed by using one photomask. Therefore,
the required amount of photomask for forming the thin film
transistor structure 234 is reduced for saving the manufacture
cost.
[0068] FIG. 24C is a schematic cross-sectional view taken along
line B-B' in the corresponding FIG. 24A. Referring to FIG. 24A,
FIG. 24B, and FIG. 24C, the pixel structure 200 includes the pixel
electrode 232a disposed on the substrate 210, the thin film
transistor structure 234, and the insulation layer 242. The thin
film transistor structure 234 is disposed on the substrate 210 and
connected to the pixel electrode 232a. The thin film transistor
structure 234 includes the source 232c, the drain 232b and the
channel 232d formed by a patterned semiconductor layer 232 and a
gate 254a formed by a gate electrode layer 254. The source 232c and
the drain 232b are located on two opposite sides of the channel
232d, and the gate 254a is located above the channel 232d. The
insulation layer 242 is interposed between the patterned
semiconductor layer 232 and the gate electrode layer 254 and has a
shape substantially conformal to the gate electrode layer 254. The
insulation layer 242 covers a portion of the patterned
semiconductor layer 232 to form the channel 232d and exposes
another portion of the patterned semiconductor layer 232 to form
the source 232c and the drain 232b.
[0069] According to the step depicted in FIG. 23A and FIG. 23B, the
covered portion 2321 of the patterned semiconductor layer 232 has a
first conductivity type and the exposed portion 232J of the
patterned semiconductor layer 232 has a second conductivity type
more conductive than the first conductivity type. Therefore, the
exposed portion 232J of the patterned semiconductor layer 232 can
from the source 232c, the drain 232b, and the pixel electrode 232a
which are elements predetermined to be electrically conductive.
[0070] For transmitting the electric signals, the pixel structure
200 further includes the data line 220c disposed on the substrate
210, located between the patterned semiconductor layer 232 and the
substrate 210, and electrically connected to the source 232c of the
thin film transistor structure 234. In addition, the gate electrode
layer 254 further includes the gate line 254b electrically
connected to the gate 254a of the thin film transistor structure
234. The gate line 254b and the data line 220c extends in different
directions for respectively transmitting a control signal to the
gate 254a and transmitting a data signal to the source 232c.
Therefore, the thin film transistor structure 234 can be turned on
by the control signal and the data signal can be transmitted to the
pixel electrode 232a through the turned-on thin film transistor
structure 234.
[0071] In the present embodiment, the gate line 254b is formed by
using the same method of forming the gate 254a. Therefore, the
insulation layer 242 includes a insulation portion 242a underlying
the gate line 254b. The insulation portion 242a conforms in shape
to the gate line 254b. The patterned semiconductor layer 232
further includes a semiconductor portion 232e underlying the gate
line 254b and has a separating gap SG corresponding to the opening
230A shown in FIG. 14A and exposing a portion of the data line
220c. The semiconductor portion 232e partially conforms in shape to
the gate line 154b. The gate line 254b, the insulation portion 242a
and the semiconductor portion 232e form a gate line structure 256,
where the gate line 254b and the insulation portion 242a of the
gate line structure 256 cross over the data line 220c at the
separating gap SG such that the semiconductor portion 232e is not
in contact with the data line 220c and the insulation portion 242a
of the insulation layer 242 fills in the separating gap SG and
contacts the data line 220c for isolating the data line 220c from
the gate line 254b. In other words, the insulation layer 242
patterned from the insulation material layer 240 fills the
separating gap SG such as the semiconductor portion 232e of the
gate lines structure 256 is electrically insulating to the data
line 220c for preventing the short circuit between the data lines
220c and the semiconductor portion 232e of the gate lines structure
256. In the embodiment, a portion of the source 232c is in direct
contact with the data line 220c by being in direct contact with the
first metal portion 220a that branches off of the data line 220c,
to electrically connect to the data line 220c. In addition, the
pixel structure 200 is different from the pixel structure 100 in
that it does not further include a second metal portion between the
drain 232b and the pixel electrode 232a. The drain 232b and the
pixel electrode 232a are connected to each other and made from the
same patterned semiconductor layer 232.
[0072] Based on the above, it should be noted that, in the
manufacturing process of the pixel structure of the embodiments,
the photoresist layer is patterned by the photomask to form the
patterned photoresist layer that includes the first thickness
portion and the second thickness portion. This allows that
patterned photoresist layer to act as a mask when etching different
portions of the stacked structure. This further allows the
manufacture of the pixel structure to require fewer masks. Thus,
the manufacturing cost of the pixel structure of the invention can
be effectively lowered.
[0073] In addition, when performing etching to expose the source
and the drain, the channel is covered by the insulation layer.
Thus, the channel of the semiconductor layer will not be damaged
during the etching process. This allows the thin film transistor
structure to have better reliability.
[0074] Furthermore, it can be seen that since the source, the
drain, and the channel are of the same patterned semiconductor
layer, the source, the drain, and the channel are electrically
connected without requiring contact holes. In addition, the drain
is electrically contacted with the pixel electrode without contact
holes. This improves resolution or aperture ratio of the pixel
structure. In addition, not requiring contact holes also saves
space in the layout of the thin film transistor structure.
[0075] It will be apparent to those skilled in the art that various
modifications and variations can be made to the structure of the
present invention without departing from the scope or spirit of the
invention. In view of the foregoing, it is intended that the
present invention cover modifications and variations of this
invention provided they fall within the scope of the following
claims and their equivalents.
* * * * *