Manufacturing method of liquid crystal display device

Abstract

A method for manufacturing a liquid crystal display that provides a wide viewing angle and in which its manufacturing processes are shortened and high reliability is provided. The method includes a process of forming a gate electrode metal layer, gate insulator, and a-Si layer and forming an island by patterning using photolithography, a process of forming an interlayer insulating film and drain electrode metal layer and forming a drain line by patterning using photolithography, a process of forming an organic insulating film and forming an organic insulating contact used to provide a connection to a source electrode and a drain electrode al a specified position by photolithography, and a process of forming a transparent conductive layer and forming a pixel electrode and common electrode by patterning using photolithography.

What is claimed is:  
     
         1 . A method for manufacturing a liquid crystal display providing a wide viewing angle in which a display with a wide viewing angle is enabled by placing a common electrode and a pixel electrode on a protecting film of a thin film transistor and by rotating a direction of a molecular axis of a liquid crystal molecule making up of a liquid crystal layer in a hermetically sealed manner on a surface being parallel to a surface of an active matrix substrate, said method comprising: 
 a process of sequentially forming a gate electrode metal layer, a gate insulator, and an a-Si (amorphous silicon) layer on a transparent insulating substrate and forming an island comprising a gate electrode, a gate insulating film, and a semiconductor layer by patterning using photolithography;    a process of sequentially forming an interlayer insulating film and a drain electrode metal layer on said transparent insulating substrate and forming a drain line by removing a specified portion of said drain electrode metal layer by patterning using photolithography;    a process of forming an insulating film on said transparent insulating substrate and forming an insulating film contact which passes through said insulating film and is used to provide a connection to a source electrode and a drain electrode at a specified position by patterning using photolithography; and    a process of forming a transparent conductive film on said transparent insulating substrate and forming said pixel electrode and said common electrode each having a comb-teeth-like configuration by removing unwanted portions of said transparent conductive film so that said pixel electrode and said common electrode are arranged in a staggered manner by patterning using photolithography and of connecting said source electrode to said pixel electrode and connecting said drain electrode to said drain line.    
     
     
         2 . The method for manufacturing the liquid crystal display providing said wide viewing angle according to  claim 1 , wherein said insulating film is made up of an inorganic insulating film existing at a lower portion of said insulating layer and of an organic insulating film existing at a upper portion of said insulating layer and wherein, after an aperture portion is formed at a specified position of said organic insulating film existing at said upper portion of said insulating film by photolithography, etching is performed on said inorganic insulating film existing at said lower portion of said insulating film using said organic insulating film existing at said upper portion of said insulating film as a mask.  
     
     
         3 . The method for manufacturing the liquid crystal display providing said wide viewing angle according to  claim 1 , wherein said gate electrode is a single layer made of a metal having a high melting point or is a two-layered film containing an upper layer made of a metal having a high melting point and a lower layer made of Al (aluminum) or an Al alloy.  
     
     
         4 . The method for manufacturing the liquid crystal display providing said wide viewing angle according to  claim 1 , wherein each of said source electrode and said drain electrode is a single layer made of a metal having a high melting point or a two-layered film containing an upper layer made of a metal having a high melting point and a lower layer made of Al (aluminum) or an Al alloy, or a three-layered film containing an upper layer made of a metal having a high melting point, an intermediate layer made of Al (Aluminum) or an Al alloy and a lower layer made of a metal having a high melting point.  
     
     
         5 . The method for manufacturing the liquid crystal display providing said wide viewing angle according to  claim 3 , wherein said metal having a high melting point is Cr (chromium) or Mo (molybdenum).  
     
     
         6 . The method for manufacturing the liquid crystal display providing said wide viewing angle according to  claim 4 , wherein said metal having a high melting point is Cr (chromium) or Mo (molybdenum).  
     
     
         7 . The method for manufacturing the liquid crystal display providing said wide viewing angle according to  claim 1 , wherein said insulating film is photosensitive.  
     
     
         8 . A method for manufacturing a liquid crystal display providing a wide viewing angle in which a display with a wide viewing angle is enabled by placing a common electrode and a pixel electrode on a protecting film of a thin film transistor and by rotating a direction of a molecular axis of a liquid crystal molecule making up of a liquid crystal layer in a hermetically sealed manner on a surface being parallel to a surface of an active matrix substrate, said method comprising: 
 a process of forming a gate electrode metal layer on a transparent insulating substrate and forming a gate electrode by patterning using photolithography;    a process of sequentially forming an interlayer insulating film, an a-Si layer (amorphous silicon), an n +  a-Si (high concentration n-type amorphous silicon) layer, and a drain electrode metal layer on said transparent insulating substrate and forming a drain line and an island by removing an unwanted portion of said drain electrode metal layer and performing patterning and then ashing processing on portions being not exposed and performing reflow processing using photolithography employing a photo resist having a plurality of regions each having a different thickness and then by removing a part of said n +  a-Si layer and a part of said a-Si layer and then by peeling said photo resist having undergone said reflow processing;    a process of forming an insulating film on said transparent insulating substrate and forming an insulating film contact which passes through said insulating film and is used to provide a connection to a source electrode of said island at a specified position by patterning using photolithography; and    a process of forming a transparent conductive film which becomes a pixel electrode on said transparent insulating substrate and forming said pixel electrode and said common electrode by removing unwanted portions of said transparent conductive film by patterning using photolithography and of connecting said pixel electrode to said source electrode.    
     
     
         9 . The method for manufacturing the liquid crystal display providing said wide viewing angle according to  claim 8 , wherein said insulating film is made up of an inorganic insulating film existing at a lower portion of said insulating layer and of an organic insulating film existing at a upper portion of said insulating layer and wherein, after an aperture portion is formed at a specified position of said organic insulating film existing at said upper portion of said insulating film by photolithography, etching is performed on said inorganic insulating film existing at said lower portion of said insulating film using said organic insulating film existing at said upper portion of said insulating film as a mask.  
     
     
         10 . The method for manufacturing the liquid crystal display providing said wide viewing angle according to  claim 8 , wherein said gate electrode is a single layer made of a metal having a high melting point or is a two-layered film containing an upper layer made of a metal having a high melting point and a lower layer made of Al (aluminum) or an Al alloy.  
     
     
         11 . The method for manufacturing the liquid crystal display providing said wide viewing angle according to  claim 8 , wherein each of said source electrode and said drain electrode is a single layer made of a metal having a high melting point or a two-layered film containing an upper layer made of a metal having a high melting point and a lower layer made of Al (aluminum) or an Al alloy, or a three-layered film containing an upper layer made of a metal having a high melting point, an intermediate layer made of Al (Aluminum) or an Al alloy and a lower layer made of a metal having a high melting point.  
     
     
         12 . The method for manufacturing the liquid crystal display providing said wide viewing angle according to  claim 10 , wherein said metal having a high melting point is Cr (chromium) or Mo (molybdenum).  
     
     
         13 . The method for manufacturing the liquid crystal display providing said wide viewing angle according to  claim 11 , wherein said metal having a high melting point is Cr (chromium) or Mo (molybdenum).  
     
     
         14 . The method for manufacturing the liquid crystal display providing said wide viewing angle according to  claim 8 , wherein said insulating film is photosensitive.  
     
     
         15 . A method for manufacturing a liquid crystal display providing a wide viewing angle in which a display with a wide viewing angle is enabled by placing a common electrode and a pixel electrode on a protecting film of a thin film transistor and by rotating a direction of a molecular axis of a liquid crystal molecule making up of a liquid crystal layer in a hermetically sealed manner on a surface being parallel to a surface of an active matrix substrate, said method comprising: 
 a process of forming a gate electrode metal layer on a transparent insulating substrate and forming a gate electrode by patterning using photolithography;    a process of sequentially forming an interlayer insulating film, an a-Si layer (amorphous silicon), an n +  a-Si layer (high concentration n-type amorphous silicon), and a drain electrode metal layer on said transparent insulating substrate and forming a drain line and an island by removing unwanted portions of said a-Si layer, said n +  a-Si layer, and said drain electrode metal layer and performing patterning and then performing ashing processing on portions being not exposed employing photo-lithography using a photo resist having a plurality of regions each having a different thickness and then by removing a specified part of said a-Si layer, said n +  a-Si layer and said drain electrode metal layer and then by peeling said portions being not exposed;    a process of forming an insulating film on said transparent insulating substrate and forming an insulating film contact which passes through said insulating film and is used to provide a connection to a source electrode of said island at a specified position by patterning using photolithography; and    a process of forming a transparent conductive film which becomes a pixel electrode on said transparent insulating substrate and forming said pixel electrode and said common electrode by removing unwanted portions of said transparent conductive film by patterning using photolithography and of connecting said pixel electrode to said source electrode.    
     
     
         16 . The method for manufacturing the liquid crystal display providing said wide viewing angle according to  claim 15 , wherein said insulating film is made up of an inorganic insulating film existing at a lower portion of said insulating layer and of an organic insulating film existing at a upper portion of said insulating layer and wherein, after an aperture portion is formed at a specified position of said organic insulating film existing at said upper portion of said insulating film by photolithography, etching is performed on said inorganic insulating film existing at said lower portion of said insulating film using said organic insulating film existing at said upper portion of said insulating film as a mask.  
     
     
         17 . The method for manufacturing the liquid crystal display providing said wide viewing angle according to  claim 15 , wherein said gate electrode is a single layer made of a metal having a high melting point or is a two-layered film containing an upper layer made of a metal having a high melting point and a lower layer made of Al (aluminum) or an Al alloy.  
     
     
         18 . The method for manufacturing the liquid crystal display providing said wide viewing angle according to  claim 15 , wherein each of said source electrode and said drain electrode is a single layer made of a metal having a high melting point or a two-layered film containing an upper layer made of a metal having a high melting point and a lower layer made of Al (aluminum) or an Al alloy, or a three-layered film containing an upper layer made of a metal having a high melting point, an intermediate layer made of Al (Aluminum) or an Al alloy and a lower layer made of a metal having a high melting point.  
     
     
         19 . The method for manufacturing the liquid crystal display providing said wide viewing angle according to  claim 17 , wherein said metal having a high melting point is Cr (chromium) or Mo (molybdenum).  
     
     
         20 . The method for manufacturing the liquid crystal display providing said wide viewing angle according to  claim 1 , wherein said metal having a high melting point is Cr (chromium) or Mo (molybdenum).  
     
     
         21 . The method for manufacturing the liquid crystal display providing said wide viewing angle according to  claim 15 , wherein said insulating film is photosensitive.  
     
     
         22 . A method for manufacturing a liquid crystal display providing a wide viewing angle in which a display with a wide viewing angle is enabled by placing a common electrode and a pixel electrode on a protecting film of a thin film transistor and by rotating a direction of a molecular axis of a liquid crystal molecule making up of a liquid crystal layer in a hermetically sealed manner on a surface being parallel to a surface of an active matrix substrate, said method comprising: 
 a process of sequentially forming a gate electrode metal layer, a gate insulator, and an a-Si (amorphous silicon) layer on a transparent insulating substrate and forming an island made up of a gate electrode, a gate insulating film, and a semiconductor layer by patterning using photolithography;    a process of sequentially forming an interlayer insulating film and a drain electrode metal layer on said transparent insulating substrate and forming a drain line by removing a specified region of said drain electrode metal layer by patterning using photolithography;    a process of forming an insulating film on said transparent insulating substrate and forming an insulating film contact which passes through said insulating film and is used to provide a connection to a source electrode and a drain electrode at a specified position by a printing method; and    a process of forming a transparent conductive film on said transparent insulating substrate and forming said pixel electrode and said common electrode each having a comb-teeth-like configuration by removing unwanted portions of said transparent conductive film so that said pixel electrode and said common electrode are arranged in a staggered manner by patterning using photolithography and of connecting said source electrode to said pixel electrode and connecting said drain electrode to said drain line.    
     
     
         23 . The method for manufacturing the liquid crystal display providing said wide viewing angle according to  claim 22 , wherein said insulating film is made up of an inorganic insulating film existing at a lower portion of said insulating layer and of an organic insulating film existing at a upper portion of said insulating layer and wherein, after an aperture portion is formed at a specified position of said organic insulating film existing a at said upper portion of said insulating film by photolithography, etching is performed on said inorganic insulating film existing at said lower portion of said insulating film using said organic insulating film existing at said upper portion of said insulating film as a mask.  
     
     
         24 . The method for manufacturing the liquid crystal display providing said wide viewing angle according to  claim 22 , wherein said gate electrode is a single layer made of a metal having a high melting point or is a two-layered film containing an upper layer made of a metal having a high melting point and a lower layer made of Al (aluminum) or an Al alloy.  
     
     
         25 . The method for manufacturing the liquid crystal display providing said wide viewing angle according to  claim 22 , wherein each of said source electrode and said drain electrode is a single layer made of a metal having a high melting point or a two-layered film containing an upper layer made of a metal having a high melting point and a lower layer made of Al (aluminum) or an Al alloy, or a three-layered film containing an upper layer made of a metal having a high melting point, an intermediate layer made of Al (Aluminum) or an Al alloy and a lower layer made of a metal having a high melting point.  
     
     
         26 . A method for manufacturing a liquid crystal display providing a wide viewing angle in which a display with a wide viewing angle is enabled by placing a common electrode and a pixel electrode on a protecting film of a thin film transistor and by rotating a direction of a molecular axis of a liquid crystal molecule making up of a liquid crystal layer in a hermetically sealed manner on a surface being parallel to a surface of an active matrix substrate, said method comprising: 
 a process of forming a gate electrode metal layer on a transparent insulating substrate and forming a gate electrode by patterning using photolithography;    a process of sequentially forming an interlayer insulating film, an a-Si layer (amorphous silicon), an n +  a-Si layer (high concentration n-type amorphous silicon), and a drain electrode metal layer on said transparent insulating substrate and forming a drain line and an island by removing unwanted portions of said drain electrode metal layer and performing patterning and then ashing and reflow processing on portions being not exposed employing photolithography using a photo resist having a plurality of regions each having a different thickness and then by removing a part of said n −  a-Si layer and a part of said a-Si layer and by peeling said photo resist having undergone said reflow processing;    a process of forming an insulating film on said transparent insulating substrate and forming an insulating film contact which passes through said insulating film and is used to provide a connection to a source electrode of said island at a specified position by a printing method; and    a process of forming an transparent conductive film which becomes said pixel electrode on said transparent insulating substrate and forming said pixel electrode and said common electrode by removing unwanted portions of said transparent conductive film by patterning using photolithography and of connecting said pixel electrode to said source electrode.    
     
     
         27 . The method for manufacturing the liquid crystal display providing said wide viewing angle according to  claim 26 , wherein said insulating film is made up of an inorganic insulating film existing at a lower portion of said insulating layer and of an organic insulating film existing at a upper portion of said insulating layer and wherein, after an aperture portion is formed at a specified position of said organic insulating film existing at said upper portion of said insulating film by photolithography, etching is performed on said inorganic insulating film existing at said lower portion of said insulating film using said organic insulating film existing at said upper portion of said insulating film as a mask.  
     
     
         28 . The method for manufacturing the liquid crystal display providing said wide viewing angle according to  claim 26 , wherein said gate electrode is a single layer made of a metal having a high melting point or is a two-layered film containing an upper layer made of a metal having a high melting point and a lower layer made of Al (aluminum) or an Al alloy.  
     
     
         29 . The method for manufacturing the liquid crystal display providing said wide viewing angle according to  claim 26 , wherein each of said source electrode and said drain electrode is a single layer made of a metal having a high melting point or a two-layered film containing an upper layer made of a metal having a high melting point and a lower layer made of Al (aluminum) or an Al alloy, or a three-layered film containing an upper layer made of a metal having a high melting point, an intermediate layer made of Al (Aluminum) or an Al alloy and a lower layer made of a metal having a high melting point.  
     
     
         30 . A method for manufacturing a liquid crystal display providing a wide viewing angle in which a display with a wide viewing angle is enabled by placing a common electrode and a pixel electrode on a protecting film of a thin film transistor and by rotating a direction of a molecular axis of a liquid crystal molecule making up of a liquid crystal layer in a hermetically sealed manner on a surface being parallel to a surface of an active matrix substrate, said method comprising 
 a process of forming a gaze electrode metal layer on a transparent insulating substrate and forming a gate electrode by patterning using photolithography;    a process of sequentially forming an interlayer insulating film, an a-Si layer (amorphous silicon), an n +  a-Si (high concentration n-type amorphous silicon) layer, and a drain electrode metal layer on said transparent insulating substrate and forming a drain line and an island by removing unwanted portions of said a-Si layer, said no a-Si layer and said drain electrode metal layer and performing patterning and then ashing on portions being not exposed employing photolithography using a photo resist having a plurality of regions each having a different thickness and then by removing a specified part of said a-Si layer, said n +  a-Si layer, and said drain electrode metal layer and then by peeling said portions being not exposed;    a process of forming an insulating film on said transparent insulating substrate and forming an insulating film contact which passes through said insulating film and is used to provide a connection to a source electrode of said island at a specified position by a printing method; and    a process of forming a transparent conductive film which becomes said pixel electrode on said transparent insulating substrate and forming said pixel electrode and said common electrode by removing unwanted portions of said transparent conductive film by patterning using photolithography and of connecting said pixel electrode to said source electrode.    
     
     
         31 . The method for manufacturing the liquid crystal display providing said wide viewing angle according to  claim 30 , wherein said insulating film is made up of an inorganic insulating film existing at a lower portion of said insulating layer and of an organic insulating film existing at a upper portion of said insulating layer and wherein, after an aperture portion is formed at a specified position of said organic insulating film existing at said upper portion of said insulating film by photolithography, etching is performed on said inorganic insulating film existing at said lower portion of said insulating film using said organic insulating film existing at said upper portion of said insulating film as a mask.  
     
     
         32 . The method for manufacturing the liquid crystal display providing said wide viewing angle according to  claim 30 , wherein said gate electrode is a single layer made of a metal having a high melting point or is a two-layered film containing an upper layer made of a metal having a high melting point and a lower layer made of Al (aluminum) or an Al alloy.  
     
     
         33 . The method for manufacturing the liquid crystal display providing said wide viewing angle according to  claim 30 , wherein each of said source electrode and said drain electrode is a single layer made of a metal having a high melting point or a two-layered film containing an upper layer made of a metal having a high melting point and a lower layer made of Al (aluminum) or an Al alloy, or a three-layered film containing an upper layer made of a metal having a high melting point, an intermediate layer made of Al (Aluminum) or an Al alloy and a lower layer made of a metal having a high melting point.