Patent Document

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  125 A 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.

Technology Category: g