Liquid crystal display device, manufacturing method thereof, and fabrication apparatus therefor

Abstract

The present invention provides a liquid crystal display device, each of gate terminals of which has a laminated structure formed of an aluminum alloy thin film and a molybdenum alloy thin film stacked on the aluminum alloy thin film, and forms respective gate lines by converting the molybdenum alloy thin film of the laminated structure into an aluminum oxide thin film in a effective displaying area of the liquid crystal display device. According to the present invention, any displaying errors of the liquid crystal display device caused by deterioration of insulation between wiring patterns formed therein (like the gate lines) during manufacturing processes thereof will be avoided without adding any fabrication steps to the manufacturing processes thereof.

What is claimed is:  
     
         1 . A liquid crystal display device, comprising: 
 a plurality of gate lines and a plurality of signal lines;    a plurality of thin film transistors, respective one of which is provided at respective intersection of one of the plurality of gate lines and one of the plurality of signal lines;    a plurality of pixel electrodes, respective one of which is electrically connected to one of the plurality of thin film transistors;    an insulating substrate at least having the plurality of gate lines, the plurality of signal lines, the plurality of thin film transistors, and the plurality of pixel electrodes being formed thereon, a region of which the plurality of pixel electrodes are formed on is utilized for an effective displaying area,    wherein an end portion of respective one of the plurality of gate lines located outside the effective displaying area has a laminated structure including an aluminum alloy film and molybdenum alloy film formed on the aluminum alloy film, and    the respective one of the plurality of gate lines has a laminated structure including the aluminum alloy film and an aluminum oxide film formed on the aluminum alloy film inside the effective displaying area.    
     
     
         2 . A liquid crystal display device according to  claim 1 , wherein the aluminum alloy film is formed of an alloy of aluminum and neodymium, and the molybdenum alloy is formed by adding at least one of elements consisting of chromium, zirconium, and hafnium to molybdenum.  
     
     
         3 . A method for manufacturing a liquid crystal display device comprising at least a plurality of gate lines and a plurality of signal lines, a plurality of thin film transistors, respective one of which is provided at respective intersection of one of the plurality of gate lines and one of the plurality of signal lines, and a plurality of pixel electrodes, respective one of which is electrically connected to one of the plurality of thin film transistors, formed on an insulating substrate thereof respectively and utilizing a region of the insulating substrate which the plurality of pixel electrodes are formed on for an effective displaying area, the method including steps of: 
 providing a laminated structure of an aluminum alloy layer and a molybdenum alloy layer stacked on the aluminum alloy layer by forming an aluminum alloy film and a molybdenum alloy film continuously in this order on the insulating substrate;    shaping the gate lines and respective gate terminal portions corresponding thereto by patterning the laminated structure of the aluminum alloy layer and the molybdenum alloy layer using photolithography technique; and    forming aluminum oxide films on surfaces of the aluminum alloy layers of the laminated structures with respect to the plurality of gate lines respectively by anodic oxidation as well as removing the respective molybdenum alloy layers on the respective surfaces of the aluminum alloy layers with respect thereto by electrolytic etching.    
     
     
         4 . A method for manufacturing the liquid crystal display device according to  claim 3 , wherein the step for oxidizing the surfaces of the aluminum alloy layers of the laminated structures with respect to the plurality of gate lines respectively by anodic oxidation as well as removing the respective molybdenum alloy layers on the respective surfaces of the aluminum alloy layers by electrolytic etching includes steps of: 
 covering a periphery of the effective displaying area on the insulating substrate with an anti-etching member;    immersing the insulating substrate the periphery of which is covered with the anti-etching member into electrolytic solution; and    disposing an electrode in the electrolytic solution and providing a electrical potential difference between the gate lines and the electrode.    
     
     
         5 . A method for manufacturing the liquid crystal display device according to  claim 4 , wherein the anti-etching member is formed of an elastic material.  
     
     
         6 . A method for manufacturing the liquid crystal display device according to  claim 4 , wherein the anti-etching member is formed of a photoresist material.  
     
     
         7 . A method for manufacturing a liquid crystal display device comprising at least a plurality of gate lines and a plurality of signal lines, a plurality of thin film transistors, respective one of which is provided at respective intersection of one of the plurality of gate lines and one of the plurality of signal lines, and a plurality of pixel electrodes, respective one of which is electrically connected to one of the plurality of thin film transistors, formed on an insulating substrate thereof respectively and utilizing a region of the insulating substrate which the plurality of pixel electrodes are formed on for an effective displaying area, the method including steps of: 
 forming a first conductive film to which anodic oxidation is applicable on the insulating substrate,    forming a second conductive film to which electrolytic etching is applicable on the first conductive film;    forming the gate lines and respective gate terminals corresponding thereto of the gate lines by etching the laminated structure by photo-etching;    covering the laminated structures shaped by the photo-etching outside of the effective displaying area with an anti-etching member;    removing the second conductive films of the laminated structures with respect to the gate lines by electrolytic etching;    forming an anodic oxide films by anodic-oxidizing surfaces of the respective first conductive films from which the second conductive films are removed; and    removing the anti-etching member.    
     
     
         8 . A method for manufacturing the liquid crystal display device according to  claim 7 , wherein the first conductive film is formed of an alloy including aluminum and at least one of titanium, tantalum, and neodymium added thereto, and the second conductive film is formed of an alloy including molybdenum and at least one of chromium, zirconium, and hafnium added thereto.  
     
     
         9 . A method for manufacturing the liquid crystal display device according to  claim 7 , wherein the anti-etching member is formed of an elastic material.  
     
     
         10 . A method for manufacturing the liquid crystal display device according to  claim 7 , wherein the anti-etching member is formed of a photoresist material.  
     
     
         11 . An apparatus for fabricating a liquid crystal display device comprising at least a plurality of gate lines and a plurality of signal lines, a plurality of thin film transistors, respective one of which is provided at respective intersection of one of the plurality of gate lines and one of the plurality of signal lines, and a plurality of pixel electrodes, respective one of which is electrically connected to one of the plurality of thin film transistors, formed on an insulating substrate thereof respectively and utilizing a region of the insulating substrate which the plurality of pixel electrodes are formed on for an effective displaying area, 
 wherein the apparatus is constituted of a base board on which the insulating substrate is disposed and a mask plate being arranged to press the insulating substrate disposed on the base board,    the mask plate comprises an rectangular opening having a substantially same shape as the effective displaying area of the insulating substrate, an anti-etching member formed of an elastic material surrounding the rectangular opening and contacting with the insulating substrate at a periphery of the effective displaying area thereof, at least two holes for supplying electrolytic solution are formed at the mask plate at different sides thereof along the rectangular opening and inside of the anti-etching member,    the apparatus supplies the electrolytic solution into a space surrounding the insulating substrate disposed on the base board and the mask plate pressed on the insulating substrate through the holes to stir the electrolytic solution along the effective displaying area of the insulating substrate surrounded by the anti-etching member.