# Patent

## Title
Array substrate for LCD panel and manufacturing method thereof

## Abstract

A manufacturing method for a substrate for an LCD panel includes providing a substrate, and applying photoresist techniques to form a first wiring layer on the substrate and patterning the first wiring layer to form a first laminating layer. An insulating layer and a semiconductor film are also formed and the semiconductor film is patterned to form a second laminating layer. A second wiring layer is formed and patterned to create a third laminating layer, a passivation layer, and a conductive film, and the conductive film is patterned to form a pixel electrode and a fourth laminating layer. The first, second, third, and fourth laminating layers stack together to form the necessary spacer. A color filter substrate with a constant gap is held between the insulating layer and the first laminating layer, and between the passivation layer and the third laminating layer.

## Background
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a divisional of U.S. patent application Ser. No. 14/336,058 filed Jul. 21, 2014.


FIELD
The disclosure generally relates to liquid crystal display (LCD) manufacturing technologies.
BACKGROUND
An LCD panel usually includes a color filter substrate, an array substrate opposite to the color filter substrate, and a liquid crystal layer set between the color filter substrate and the array substrate. The array substrate includes a number of spacers to hold the color filter substrate with a constant gap. However, a specific exposure step is need to make the spacers, which increases LCD panel cost.



BRIEF DESCRIPTION OF THE DRAWINGS
Many aspects of the disclosure can be better understood with reference to the following drawings. The components in the drawings are not necessarily drawn to scale, the emphasis instead being placed upon clearly illustrating the principles of the disclosure. Moreover, in the drawings, like reference numerals designate corresponding parts throughout the views.
FIG. 1 is a diagrammatic view of an array substrate of a LCD panel of an exemplary embodiment.
FIG. 2 is a cross-sectional view of the array substrate of FIG. 1, taken along line II-II.
FIG. 3 is a flowchart of an exemplary embodiment of a method of manufacture of the array substrate of FIG. 1, the method of manufacture having blocks 801-814.
FIGS. 4-19 are cross-sectional views respectively corresponding to blocks 801-814 of FIG. 3.



DETAILED DESCRIPTION
The disclosure is illustrated by way of example and not by way of limitation in the figures of the accompanying drawings in which like references indicate similar elements. It should be noted that references to “an” or “one” embodiment in this disclosure are not necessarily to the same embodiment, and such references can mean “at least one.”
FIG. 1 illustrates an array substrate 12 of an LCD panel of an exemplary embodiment. FIG. 2 illustrates a cross-sectional view of the array substrate 12. Referring to FIGS. 1 and 2, the array substrate 12 includes a substrate 120, a first wiring layer 121, a second wiring layer 122, an insulating layer 123, a semiconductor film 124, a passivation layer 125, a conductive film 126, and a plurality of spacers 129. The substrate 120 is transparent, for instance, made of glass. The spacer 129 is a laminating structure.
The first wiring layer 121 is set on a surface of the substrate 120 and includes a gate line 130 extending along a first direction, a gate electrode 132 connected to the gate line 130, and a first laminating layer 136. In this embodiment, the gate electrode 132 protrudes from a side of the gate line 130. A first photoresist layer 138 applied to the first wiring layer 121 is exposed and developed to form the gate line 130, the gate electrode 132, and the first laminating layer 136. Apart of the first photoresist layer 138 covering the first laminating layer 136 remains as one layer of the laminating structure of the spacer 129. In this embodiment, the first laminating layer 136 is a first layer of the spacer 129 and the first photoresist 138 is a second layer of the spacer 129.
The insulating layer 123 is formed on the substrate 120 to cover the gate line 130, the gate electrode 132, the first laminating layer 136, and the first photoresist layer 138. The insulating layer 123 is used as a gate insulator. In this embodiment, a part of the insulating layer 123 which overlaps with the first photoresist layer 138 is a third layer of the spacer 129.
The semiconductor film 124 is formed on a surface of the insulating layer 123. A second photoresist layer 148 applied on the semiconductor film 124 is exposed and developed to form a channel layer 140 and a second laminating layer 146. The channel layer 140 is located to correspond to the gate electrode 132. The second laminating layer 146 is stacked with the first photoresist layer 138. A part of the second photoresist layer 148 which covers the second laminating layer 146 remains as one layer of the laminating structure of the spacer 129. In this embodiment, the second laminating layer 146 is a fourth layer of the spacer 129 and the second photoresist layer 148 is a fifth layer of the spacer 129.
The second wiring layer 122 is formed on the semiconductor film 124 and the insulating layer 123. The second wiring layer 122 is electrically isolated from the first wiring layer 121. A third photoresist layer 158 applied to the second wiring layer 122 is exposed and developed to form a source line 150, a source electrode 152, a drain electrode 154, and a third laminating layer 156. The source electrode 152 and the drain electrode 154 overlap with the semiconductor film 124. The third laminating layer 156 is stacked with the second photoresist layer 148. A part of the third photoresist layer 158 which covers the third laminating layer 156 remains as one layer of the laminating structure of the spacer 129. In this embodiment, the third laminating layer 156 is a sixth layer of the spacer 129 and the third photoresist layer 158 is a seventh layer of the spacer 129.
The source line 150 extends along a second direction different from the first direction. The source line 150 crosses with the gate line 130 to define a pixel area. The source electrode 152 is connected to the source line 150. The source electrode 152 is electrically connected to the drain electrode 154 via the channel layer 140. The source electrode 152, the drain electrode 154, and the channel layer 140 together comprise and function as a thin film transistor (TFT) 159. In this embodiment, the thin film transistor 159 is located at a corner where the source line 150 crosses the gate line 130.
The passivation layer 125 is formed on the substrate 120 to cover the insulating layer 123, the semiconductor layer 124, the second wiring layer 122, and the third photoresist layer 158 formed on the third laminating layer 156. In this embodiment, a part of the passivation layer 125 which covers the third photoresist layer 158 is an eighth layer of the spacer 129.
The conductive film 126 is formed on the passivation layer 125. A fourth photoresist layer 168 applied to the conductive film 126 is exposed and developed to form a pixel electrode 160 and a fourth laminating layer 166. The pixel electrode 160 is electrically connected to the drain electrode 154 via a connecting through hole 125A defined in the passivation layer 125. A part of the fourth photoresist layer 168 covering the fourth laminating layer 166 remains as one layer of the laminating structure of the spacer 129. In this embodiment, the fourth laminating layer 168 is a ninth layer of the spacer 129 and the fourth photoresist layer 168 is a tenth layer of the spacer 129.
It is understood that a sequence of laminating layers of the spacer 129 can be changed according to a priority of manufacturing steps of the first wiring layer 121, the second wiring layer 122, the insulating layer 123, the semiconductor film 124, the passivation film 125, and the conductive film 126. The first photoresist layer 138, the second photoresist layer 148, the third photoresist layer 158, and/or the fourth photoresist layer 168 can be omitted from the laminating structure of the spacer 129.
FIG. 3 is a flowchart of an exemplary embodiment of an array substrate manufacturing method for an LCD panel. The spacer 129 of the array substrate 12 is formed with the TFT 159 and the pixel electrode 160 of the array substrate 12. In this embodiment, the TFT 159 is a bottom gate type TFT. It is understood that, in the other embodiments, the TFT 159 can be different types of TFTs, for instance, a top gate type TFT. A priority of the manufacturing steps can be changed according to the structure of the TFT 159.
In block 801, referring also to FIG. 4, the substrate 120 is provided and the first wiring layer 121 is formed on the substrate 120. The substrate 120 can be made of an insulating material, for example, glass, quartz, or a ceramic. The first wiring layer 121 can be made of a conductive material, for example, aluminum, molybdenum, chromium, tantalum, or copper.
In block 802, the first photoresist layer 138 is formed on the first wiring layer 121 to pattern the first wiring layer 121. A first mask 300 is placed above the first photoresist layer 138. The first mask 300 is a gray tone mask and includes a plurality of first areas 301, two second areas 302, and a third area 303. Transparencies of the first areas 301, the second areas 302, and the third area 303 gradually decrease. In this embodiment, the third area 303 is opaque, the first areas 301 of the first mask 300 are entirely transparent, and the second areas 302 allow a portion of light to pass through. The second areas 302 are respectively aligned with positions of the gate line 130 and the gate electrode 132 (see FIG. 1). The third area 303 is aligned with a position of the spacer 129 (see FIG. 1). The first areas 301 are aligned with the remaining portions of the array substrate 12. Ultraviolet light passes through the first mask 300 to irradiate the first photoresist layer 138. The transparencies of the first areas 301, the second areas 302, and the third area 303 are different from each other, thus different parts of the first photoresist layer 138 aligned with the first areas 301, the second areas 302, and the third areas 303 are irradiated at different intensities.
Referring to FIG. 5, the first photoresist layer 138 is developed. A plurality of first parts of the first photoresist layer 138 aligned with the first areas are totally removed. Two second parts of the first photoresist layer 138 aligned with the two second areas 302 are partially removed. A third part of the first photoresist layer 138 aligned with the third area 303 remains unremoved. A thickness of the third part of the first photoresist layer 138 aligned to the third area 303 is greater than a thickness of the second parts of the first photoresist layer 138 aligned to the second areas 302.
Referring to FIG. 6, a part of the first wiring layer 121 uncovered by the first photoresist layer 138 is etched away. That is, the part of the first wiring layer 121 aligned to the first areas 301 is etched away.
In block 803, referring to FIG. 7, the first photoresist layer 138 is etched until the second parts of the first photoresist layer 138 aligned with the second areas 302 are totally removed. Since the thickness of the third part of the first photoresist layer 138 aligned with the third area 303 is greater than the thickness of the second parts of the first photoresist layer 138 aligned with the second areas 302 of the first mask 300, the third part of the first photoresist layer 138 aligned with the third area 303 of the first mask 300 remains unremoved when the second parts of the first photoresist layer 138 aligned with the second areas 302 of the first mask 300 are totally removed. A part of the first wiring layer 121 uncovered by the first photoresist layer 138 is used as the gate line 130 and the gate electrode 132. The other parts of the first wiring layer 121 covered by the remaining third part of the first photoresist layer 138 is used as the first laminating layer 136 of the spacer 129.
In block 804, also referring to FIG. 8, the insulating layer 123 is formed on the substrate 120 to cover the first wiring layer 121 and the remaining third part of the first photoresist layer 138. A part of the insulating layer 123 covering the remaining third part of the first photoresist layer 138 is used as one layer of the laminating structure of the spacer 129 (see FIG. 2).
In block 805, the semiconductor film 124 is formed on the insulating layer 123. The semiconductor film 124 can be made of a metal oxide semiconductor material.
In block 806, the second photoresist layer 148 is formed on the semiconductor film 124 to pattern the semiconductor film 124. A second mask 400 is placed above the second photoresist layer 148. The second mask 400 is a gray tone mask and includes a number of first areas 401, a second area 402, and a third area 403. The respective transparencies of the first areas 401, the second area 402, and the third area 403 gradually decrease. In this embodiment, the third area 403 is opaque, the first areas 401 are transparent, and the second area 402 allows a portion of light to pass through. The second area 402 is aligned with a position of the channel layer 140 (see FIG. 1). The third area 403 is aligned with the position of the spacer 129 (see FIG. 1). The first areas 401 are aligned with the remaining portions of the array substrate 12. Ultraviolet light passes through the second mask 400 to irradiate the second photoresist layer 148.
Referring to FIG. 9, the second photoresist layer 148 is developed. A number of first parts of the second photoresist layer 148 aligned with the first areas 401 are totally removed. A second part of the second photoresist layer 148 aligned with the second area 402 of the second mask 400 is partially removed. A third part of the second photoresist layer 148 aligned to the third area 403 remains unremoved. A thickness of the third part of the second photoresist layer 148 aligned with the third area 403 is greater than a thickness of the second part of the second photoresist layer 148 aligned with the second area 402.
Referring to FIG. 10, a part of the semiconductor film 124 uncovered by the second photoresist layer 148 is etched away. That is, the part of the semiconductor film 124 aligned with the first area 401 is etched away. A part of the semiconductor film 124 aligned with the second area 402 is patterned to form the channel layer 140. A part of the semiconductor film 124 aligned with the third area 403 is patterned to form the second laminating layer 146 of the spacer 129. The second laminating layer 146 is stacked with the first laminating 136 layer.
In block 807, referring also to FIG. 11, the second photoresist layer 148 is etched away until the second part of the second photoresist layer 148 aligned with the second area 402 is totally removed. Since the thickness of the third part of the second photoresist layer 148 aligned to the third area 403 is greater than the thickness of the second part of the second photoresist layer 148 aligned with the second area 402, the third part of the second photoresist layer 148 aligned with the third area 403 remains unremoved when the second part of the first photoresist layer 148 aligned with the second area 402 is totally removed. The remaining third part of the second photoresist layer 148 is used as one layer of the laminating structure of the spacer 129 (see FIG. 2).
Referring to FIG. 12, in block 808, the second wiring layer 122 is formed on the substrate 120 to cover the insulating layer 123, the semiconductor film 124, and the second photoresist layer 148.
In block 809, the third photoresist layer 158 is formed on the second wiring layer 122 to pattern the second wiring layer 122. A third mask 500 is placed above the third photoresist layer 158. The third mask 500 is a gray tone mask and includes a plurality of first areas 501, three second areas 502, and a third area 503. Respective transparencies of the first areas 501, the second areas 502, and the third area 503 gradually decrease. In this embodiment, the third area 503 is opaque, the first areas 501 are transparent, and the second areas 502 allow a portion of light to pass through. The three second areas 502 are respectively aligned with positions of two branches of the source electrode 152 and the drain electrode 154 (see FIG. 1). The third area 503 is aligned with the position of the spacer 129. The first areas 501 are aligned with the remaining portions of the array substrate 12. Ultraviolet light passes through the third mask 500 to irradiate the third photoresist layer 158.
Referring to FIG. 13, the third photoresist layer 158 is developed. A plurality of first parts of the third photoresist layer 158 aligned with the first areas 501 are totally removed. Three second parts of the third photoresist layer 158 aligned with the three second areas 502 are partially removed. A third part of the first photoresist layer 158 aligned with the third area 503 remains unremoved. A thickness of the third part of the third photoresist layer 158 aligned with the third area 503 is greater than a thickness of the second parts of the third photoresist layer 158 aligned with the second areas 502.
Referring to FIG. 14, a part of the second wiring layer 122 uncovered by the third photoresist layer 158 is etched away. That is, the part of the second wiring layer 122 aligned with the first areas 501 is etched away. A portion of the second wiring layer 122 aligned with the second areas 502 is patterned to form the source line 150 (see FIG. 1), the source electrode 152, and the drain electrode 154. A portion of the second wiring layer 122 aligned with the third area 503 is patterned to form the third laminating layer 156 of the spacer 129. The third laminating layer 156 is stacked with the first laminating layer 146 and the second laminating layer 136.
In block 810, referring also to FIG. 15, the third photoresist layer 158 is etched away until the second parts of the third photoresist layer 158 aligned with the second areas 502 are totally removed. Since the thickness of the third part of the third photoresist layer 158 aligned with the third area 503 is greater than the thickness of the second parts of the third photoresist layer 158 aligned with the second areas 502, the third part of the third photoresist layer 158 aligned with the third area 503 remains unremoved the second parts of the third photoresist layer 158 aligned with the second areas 502 is totally removed. The remaining third part of the third photoresist layer 158 is used as one layer of the laminating structure of the spacer 129 (see FIG. 2).
Referring to FIG. 16, in block 811, the passivation layer 125 is formed to cover the insulating layer 123, the semiconductor film 124, the second wiring layer 122, and the third photoresist layer 158. A part of the passivation layer 125 covering the remaining third part of the third photoresist layer 158 is used as one layer of the laminating structure of the spacer 129 (see FIG. 2).
In block 812, a conductive film 126 is formed on the passivation layer 125. In this embodiment, the conductive film 126 is made of indium tin oxide (ITO).
In block 813, the fourth photoresist layer 168 is formed on the conductive film 126 to pattern the conductive film 126. A fourth mask 600 is placed above the fourth photoresist layer 168. The fourth mask 600 is a gray tone mask and includes a plurality of first areas 601, a second area 602, and a third area 603. Respective transparencies of the first areas 601, the second area 602, and the third area 603 gradually decrease. In this embodiment, the third area 603 is opaque, the first areas 601 are transparent, and the second area 602 allows a portion of light to pass through. The second area 602 is aligned with a position of the pixel electrode 160 (see FIG. 1). The third area 603 is aligned with the position of the spacer 129 (see FIG. 1). The first areas 601 are aligned with the remaining portion of the array substrate 12. Ultraviolet light passes through the fourth mask 600 to irradiate the fourth photoresist layer 168.
Referring to FIG. 17, the fourth photoresist layer 168 is developed. A number of first parts of the fourth photoresist layer 168 aligned with the first areas 601 are totally removed. A second part of the fourth photoresist layer 168 aligned with the second area 602 is partially removed. A third part of the fourth photoresist layer 168 aligned with the third area 603 remains unremoved. A thickness of the third part of the fourth photoresist layer 168 aligned with the third area 603 is greater than a thickness of the second part of the fourth photoresist layer 168 aligned with the second area 602.
Referring to FIG. 18, a portion of the conductive film 126 uncovered by the fourth photoresist layer 168 is etched away. That is, the portion of the conductive film 126 aligned to the first area 601 is etched away. A portion of the conductive film 126 aligned with the second area 602 is patterned to form the pixel electrode 160. A portion of conductive film 126 aligned with the third area 603 is patterned to form the fourth laminating layer 166 of the spacer 129 (see FIG. 2). The fourth laminating layer 166 is stacked with the first laminating layer 136, the second laminating layer 146, and the third laminating layer 156.
In block 814, referring also to FIG. 19, the fourth photoresist layer 168 is etched away until the second part of the fourth photoresist layer 168 aligned with the second area 602 is totally removed. Since the thickness of the third part of the fourth photoresist layer 168 aligned with the third area 603 is greater than the thickness of the second part of the fourth photoresist layer 168 aligned with the second area 602, the third part of the fourth photoresist layer 168 aligned with the third area 603 remains unremoved when the second part of the fourth photoresist layer 168 aligned with the second area 602 is totally removed. The remaining third part of the fourth photoresist layer 168 is used as one layer of the laminating structure of the spacer 129 (see FIG. 2).
It is believed that the present embodiments and their advantages will be understood from the foregoing description, and it will be apparent that various changes may be made thereto without departing from the scope of the disclosure or sacrificing all of its material advantages, the examples hereinbefore described merely being preferred or exemplary embodiments.

## Claims

1. A manufacturing method of an array substrate for an LCD panel, the manufacturing method comprising:
providing a substrate;
forming a first wiring layer on the substrate and patterning the first wiring layer to form a gate line, a gate electrode connected to the gate line, and a first laminating layer;
forming an insulating layer;
forming a semiconductor film and patterning the semiconductor film to form a channel layer corresponding to the gate electrode and a second laminating layer stacked on the first laminating layer;
forming a second wiring layer and patterning the second wiring layer to form a source line, a source electrode connected to the source line, a drain electrode electrical coupled to the source electrode via the channel layer, and a third laminating layer stacked on the first laminating layer and the second laminating layer in that order;
forming a passivation layer; and
forming a conductive film and patterning the conductive film to a pixel electrode connected to the drain electrode and a fourth laminating layer stacked on the first laminating layer;
wherein a spacer having a laminating structure is formed by stacking at least the first laminating layer, the second laminating layer, the third laminating layer, the fourth laminating layer, a portion of the insulating layer overlapped with the first laminating layer, and a portion of the passivation layer overlapped with the third laminating layer, the spacer is configured to hold a color filter substrate with a constant gap.

2. The manufacturing method of claim 1, wherein the first wiring layer is patterned by forming a first photoresist layer on the first wiring layer, exposing and developing the first photoresist layer, and a part of the first photoresist layer located on the first laminating layer is remained to form one layer of the spacer.

3. The manufacturing method of claim 1, wherein the semiconductor film is patterned by forming a second photoresist layer on the semiconductor film, exposing and developing the second photoresist layer, and a portion of the second photoresist layer located on the second laminating layer remains to form one layer of the spacer.

4. The manufacturing method of claim 1, wherein the second wiring layer is patterned by forming a third photoresist layer on the second wiring layer, exposing and developing the third photoresist layer, and a portion of the third photoresist layer located on the third laminating layer remains to form one layer of the spacer.

5. The manufacturing method of claim 1, wherein the conductive film is patterned by forming a fourth photoresist layer on the conductive film, exposing and developing the fourth photoresist layer, and a portion of the fourth photoresist layer located on the fourth laminating layer remains to form one layer of the spacer.

6. The manufacturing method of claim 1, wherein the first laminating layer and the gate electrode are simultaneously formed under a same first mask with different transmittances on different areas; the second laminating layer and the channel layer are simultaneously formed under a same second mask with different transmittances on different areas; the third laminating layer and the drain electrode are simultaneously formed under a same third mask with different transmittances on different areas.