Active matrix liquid-crystal display device and method for making the same

Abstract

Disclosed is a method for making an active matrix liquid-crystal display device, this method having the steps of: forming interlayer insulating film, at least part of which composed of organic film, on a TFT(thin-film transistor) substrate with a structure where a pixel electrode and wiring are overlapped; patterning the organic film; and patterning a base layer using the patterned organic film as a mask. Also disclosed is an active matrix liquid-crystal display device, which has: a TFT(thin-film transistor) substrate with a structure where a pixel electrode and wiring are overlapped; and interlayer insulating film, at least part of which composed of organic film; wherein the organic film has a transmissivity of greater than 90% to g-line light and the heat resistance of organic film is higher than 250° C.

What is claimed is:  
     
         1 . A method for making an active matrix liquid-crystal display device, comprising the steps of: 
 forming interlayer insulating film, at least part of which composed of organic film, on a TFT(thin-film transistor) substrate with a structure where a pixel electrode and wiring are overlapped;    patterning said organic film; and    patterning a base layer using the patterned organic film as a mask.    
     
     
         2 . A method for making an active matrix liquid-crystal display device, according to  claim 1 , wherein 
 said organic film patterning step is conducted by wet etching, and said patterning of said base layer is conducted by dry etching using at least one kind of gas selected from O 2 , CF 4 , CHF 3  and SF 6 .    
     
     
         3 . A method for making an active matrix liquid-crystal display device, according to  claim 2 , further comprising the steps of: 
 forming organic film by applying resin and pre-baking it;    forming a resist pattern by applying resist on the surface of the formed organic film, and by baking, exposing and developing it;    forming a pattern of said organic film by wet-etching said organic film using said resist pattern as a mask;    dry-etching said base layer using said organic film pattern as a mask;    removing said resist; and    completely hardening said organic film pattern by re-baking.    
     
     
         4 . A method for making an active matrix liquid-crystal display device, according to  claim 3 , wherein: 
 said resist is of positive-type resist using naphthoquinonediazo compound as a photosensitive agent, novolac resin as base resin and methylamine-system solvent or propyleneglycolmonoethyletheracetate solvent as a solvent,    said developing is conducted using tetramethylammoniumhydroxide (TMAH) solution, and    said removing of resist is conducted using a mixed solution of dimethylsulfoxide (DMSO) and monoethanolamine, ethyllactate or butyllactate.    
     
     
         5 . A method for making an active matrix liquid-crystal display device, according to  claim 4 , wherein: 
 said organic film forming step is conducted by applying benzocyclobutene polymer using propyleneglycolmonoethyletheracetate as a solvent and pre-baking in the temperature range of 130 to 200° C.,    said organic film pattern forming step is conducted by wet-etching the organic film using a mixed solution of 1,3,5 triisopropylbenzene and aromatic system hydrocarbon or a mixed solution of glycolether and synthetic isoparaffin-system hydrocarbon, and    said organic film hardening step is conducted by re-baking in the temperature range of 240 to 300° C.    
     
     
         6 . A method for making an active matrix liquid-crystal display device, according to  claim 4 , wherein: 
 said organic film forming step is conducted by applying polysilazane compound or a polymer of polysilazane compound and acrylic compound and pre-baking in the temperature range of 130 to 200° C.,    said organic film pattern forming step is conducted by wet-etching the organic film using a buffered hydrofluoric acid solution, and    said organic film hardening step is conducted by re-baking in the temperature range of 240 to 300° C.    
     
     
         7 . A method for making an active matrix liquid-crystal display device, according to  claim 2 , wherein: 
 said organic film pattern forming step is conducted so that the development of resist and the etching of organic film are simultaneously conducted.    
     
     
         8 . A method for making an active matrix liquid-crystal display device, according to  claim 7 , further comprising the steps of: 
 forming organic film by applying resin and then pre-baking it;    applying resist on the surface of the formed organic film, baking, exposing it;    forming a pattern of said organic film by wet-etching said organic film simultaneously with forming a resist pattern by developing said resist;    dry-etching said base layer using said organic film pattern as a mask;    removing said resist; and    completely hardening said organic film pattern by re-baking.    
     
     
         9 . A method for making an active matrix liquid-crystal display device, according to  claim 8 , wherein: 
 said resist is of positive-type resist using naphthoquinonediazo compound as a photosensitive agent, novolac resin as base resin and methylamine-system solvent, propyleneglycolmonoethyletheracetate solvent, 2-heptanone, ethyl-3-ethoxypropionate, or a mixed solvent of 2-heptanone and ethyl-3-ethoxypropionate as a solvent,    said developing of resist and said wet-etching of organic film are conducted using tetramethylammoniumhydroxide (TMAH) solution, and    said removing of resist is conducted using a mixed solution of dimethylsulfoxide (DMSO) and monoethanolamine, ethyllactate or butyllactate.    
     
     
         10 . A method for making an active matrix liquid-crystal display device, according to  claim 9 , wherein: 
 said organic film forming step is conducted by applying a polymer of Cardo-type compound represented by structural formula [1] and a compound with epoxy group represented by structural formula [2] and pre-baking in the temperature range of 110 to 170° C., and    said organic film hardening step is conducted by re-baking in the temperature range of 230 to 280° C.                          
     
     
         11 . A method for making an active matrix liquid-crystal display device, according to  claim 9 , wherein: 
 said organic film forming step is conducted by applying acrylic resin and pre-baking in the temperature range of 80 to 100° C., and    said organic film hardening step is conducted by re-baking in the temperature range of 220 to 260° C.    
     
     
         12 . A method for making an active matrix liquid-crystal display device, according to  claim 7 , further comprising the steps of: 
 forming organic film by applying thermosetting resin and then pre-baking it;    applying resist on the surface of the formed organic film, baking, exposing it;    forming a pattern of said organic film by wet-etching said organic film simultaneously with forming a resist pattern by developing said resist;    insolubilizing said organic film pattern to a developer by semi-hardening it by thermal cross-linking reaction;    dry-etching said base layer using said organic film pattern as a mask;    solubilizing said resist to the developer by radiating UV light onto at least one of the front and back surfaces of substrate;    removing said resist using said developer; and    completely hardening said organic film pattern by re-baking.    
     
     
         13 . A method for making an active matrix liquid-crystal display device, according to  claim 12 , wherein: 
 said resist is of positive-type resist using naphthoquinonediazo compound as a photosensitive agent, novolac resin as base resin and methylamine-system solvent, propyleneglycolmonoethyletheracetate solvent, 2-heptanone, ethyl-3-ethoxypropionate, or a mixed solvent of 2-heptanone and ethyl-3-ethoxypropionate as a solvent, and    said developing of resist, said wet-etching of organic film and said removing of resist are conducted using tetramethylammoniumhydroxide (TMAH) solution.    
     
     
         14 . A method for making an active matrix liquid-crystal display device, according to  claim 9 , wherein: 
 said organic film forming step is conducted by applying acrylic resin and resin including a photopolymerization initiator and pre-baking in the temperature range of 80 to 110° C., and    said organic film hardening step is conducted by re-baking in the temperature range of 220 to 260° C.    
     
     
         15 . A method for making an active matrix liquid-crystal display device, according to  claim 13 , wherein: 
 said organic film forming step is conducted by applying acrylic resin and resin including a photopolymerization initiator and pre-baking in the temperature range of 80 to 110° C., and    said organic film hardening step is conducted by re-baking in the temperature range of 220 to 260° C.    
     
     
         16 . A method for making an active matrix liquid-crystal display device, according to  claim 7 , further comprising the steps of: 
 forming organic film by applying UV-setting resin which is sensitive to light of i-line or a shorter wavelength and then pre-baking it;    applying resist on the surface of the formed organic film and baking it;    exposing it with light of g-line;    forming a pattern of said organic film by wet-etching said organic film simultaneously with forming a resist pattern by developing said resist;    radiating UV light onto at least one of the front and back surfaces of substrate, thereby insolubilizing said organic film pattern to a developer by semi-hardening said organic film pattern through cross-linking reaction and solubilizing said resist to the developer;    dry-etching said base layer using said organic film pattern as a mask;    removing said resist using said developer; and    completely hardening said organic film pattern by re-baking.    
     
     
         17 . A method for making an active matrix liquid-crystal display device, according to  claim 16 , wherein: 
 said resist is of g-line-photosensitive positive-type resist using naphthoquinonediazo compound as a photosensitive agent, novolac resin as base resin and methylamine-system solvent, propyleneglycolmonoethyletheracetate solvent as a solvent and said developing of resist, said wet-etching of organic film and said removing of resist are conducted using tetramethylammoniumhydroxide (TMAH) solution.    
     
     
         18 . A method for making an active matrix liquid-crystal display device, according to  claim 9 , wherein: 
 said organic film forming step is conducted by applying a polymer of Cardo-type compound represented by structural formula [1] and a compound with epoxy group represented by structural formula [2], and resin including a photopolymerization initiator, and then pre-baking in the temperature range of 80 to 150° C., and    said organic film hardening step is conducted by re-baking in the temperature range of 230 to 280° C.    
     
     
         19 . A method for making an active matrix liquid-crystal display device, according to  claim 16 , wherein: 
 said organic film forming step is conducted by applying a polymer of Cardo-type compound represented by structural formula [1] and a compound with epoxy group represented by structural formula [2], and resin including a photopolymerization initiator, and then pre-baking in the temperature range of 80 to 150° C., and    said organic film hardening step is conducted by re-baking in the temperature range of 230 to 280° C.    
     
     
         20 . An active matrix liquid-crystal display device, comprising: 
 a TFT(thin-film transistor) substrate with a structure where a pixel electrode and wiring are overlapped; and    interlayer insulating film, at least part of which composed of organic film;    wherein said organic film has a transmissivity of greater than 90% to g-line light and the heat resistance of organic film is higher than 250° C.    
     
     
         21 . An active matrix liquid-crystal display device, according to  claim 20 , wherein: 
 said organic film is of benzocyclobutene polymer.    
     
     
         22 . An active matrix liquid-crystal display device, according to  claim 20 , wherein: 
 said organic film is of polysilazane compound or a polymer of polysilazane compound and acrylic compound.    
     
     
         23 . An active matrix liquid-crystal display device, according to  claim 20 , wherein: 
 said organic film is of a polymer of Cardo-type compound represented by structural formula [1] and a compound with epoxy group represented by structural formula [2].                          
     
     
         24 . An active matrix liquid-crystal display device, according to  claim 20 , wherein: 
 said organic film is of acrylic-system resin.    
     
     
         25 . An active matrix liquid-crystal display device, according to  claim 20 , wherein said interlayer insulating film is formed by conducting the steps of: 
 patterning said organic film composing at least part of said interlayer insulating film; and    patterning a base layer using the patterned organic film as    
     
     
         26 . An active matrix liquid-crystal display device, according to  claim 21 , wherein said interlayer insulating film is formed by conducting the steps of: 
 patterning said organic film composing at least part of said interlayer insulating film; and    patterning a base layer using the patterned organic film as a mask.    
     
     
         27 . An active matrix liquid-crystal display device, according to  claim 22 , wherein said interlayer insulating film is formed by conducting the steps of: 
 patterning said organic film composing at least part of said interlayer insulating film; and    patterning a base layer using the patterned organic film as a mask.    
     
     
         28 . An active matrix liquid-crystal display device, according to  claim 23 , wherein said interlayer insulating film is formed by conducting the steps of: 
 patterning said organic film composing at least part of said interlayer insulating film; and    patterning a base layer using the patterned organic film as a mask.    
     
     
         29 . An active matrix liquid-crystal display device, according to  claim 24 , wherein said interlayer insulating film is formed by conducting the steps of: 
 patterning said organic film composing at least part of said interlayer insulating film; and    patterning a base layer using the patterned organic film as a mask.    
     
     
         30 . An active matrix liquid-crystal display device, according to  claim 29 , wherein: 
 said organic film patterning step is conducted by wet etching, and said patterning of said base layer is conducted by dry etching using at least one kind of gas selected from O 2 , CF 4 , CHF 3  and SF 6 .    
     
     
         31 . An active matrix liquid-crystal display device, according to  claim 30 , wherein said interlayer insulating film is formed by conducting further the steps of: 
 forming organic film by applying resin and pre-baking it;    forming a resist pattern by applying resist on the surface of the formed organic film, and by baking, exposing and developing it;    forming a pattern of said organic film by wet-etching said organic film using said resist pattern as a mask;    dry-etching said base layer using said organic film pattern as a mask;    removing said resist; and    completely hardening said organic film pattern by re-baking.    
     
     
         32 . An active matrix liquid-crystal display device, according to  claim 31 , wherein: 
 said resist is of positive-type resist using naphthoquinonediazo compound as a photosensitive agent, novolac resin as base resin and methylamine-system solvent or propyleneglycolmonoethyletheracetate solvent as a solvent,    said developing is conducted using tetramethylammoniumhydroxide (TMAH) solution, and    said removing of resist is conducted using a mixed solution of dimethylsulfoxide (DMSO) and monoethanolamine, ethyllactate or butyllactate.    
     
     
         33 . An active matrix liquid-crystal display device, according to  claim 32 , wherein: 
 said organic film forming step is conducted by applying benzocyclobutene polymer using propyleneglycolmonoethyletheracetate as a solvent and pre-baking in the temperature range of 130 to 200° C.,    said organic film pattern forming step is conducted by wet-etching the organic film using a mixed solution of 1,3,5 triisopropylbenzene and aromatic system hydrocarbon or a mixed solution of glycolether and synthetic isoparaffin-system hydrocarbon, and    said organic film hardening step is conducted by re-baking in the temperature range of 240 to 300° C.    
     
     
         34 . An active matrix liquid-crystal display device, according to  claim 32 , wherein: 
 said organic film forming step is conducted by applying polysilazane compound or a polymer of polysilazane compound and acrylic compound and pre-baking in the temperature range of 130 to 200° C.,    said organic film pattern forming step is conducted by wet-etching the organic film using a buffered hydrofluoric acid solution, and    said organic film hardening step is conducted by re-baking in the temperature range of 240 to 300° C.    
     
     
         35 . An active matrix liquid-crystal display device, according to  claim 30 , wherein: 
 said organic film pattern forming step is conducted so that the development of resist and the etching of organic film are simultaneously conducted.    
     
     
         36 . An active matrix liquid-crystal display device, according to  claim 35 , wherein said interlayer insulating film is formed by conducting further the steps of: 
 forming organic film by applying resin and then pre-baking it;    applying resist on the surface of the formed organic film, baking, exposing it;    forming a pattern of said organic film by wet-etching said organic film simultaneously with forming a resist pattern by developing said resist;    dry-etching said base layer using said organic film pattern as a mask;    removing said resist; and    completely hardening said organic film pattern by re-baking.    
     
     
         37 . An active matrix liquid-crystal display device, according to  claim 36 , wherein: 
 said resist is of positive-type resist using naphthoquinonediazo compound as a photosensitive agent, novolac resin as base resin and methylamine-system solvent, propyleneglycolmonoethyletheracetate solvent, 2-heptanone, ethyl-3-ethoxypropionate, or a mixed solvent of 2-heptanone and ethyl-3-ethoxypropionate as a solvent,    said developing of resist and said wet-etching of organic film are conducted using tetramethylammoniumhydroxide (TMAH) solution, and    said removing of resist is conducted using a mixed solution of dimethylsulfoxide (DMSO) and monoethanolamine, ethyllactate or butyllactate.    
     
     
         38 . An active matrix liquid-crystal display device, according to  claim 37 , wherein: 
 said organic film forming step is conducted by applying a polymer of Cardo-type compound represented by structural formula [1] and a compound with epoxy group represented by structural formula [2] and pre-baking in the temperature range of 110 to 170° C., and    said organic film hardening step is conducted by re-baking in the temperature range of 230 to 280° C.    
     
     
         39 . An active matrix liquid-crystal display device, according to  claim 37 , wherein: 
 said organic film forming step is conducted by applying acrylic resin and pre-baking in the temperature range of 80 to 100° C., and    said organic film hardening step is conducted by re-baking in the temperature range of 220 to 260° C.    
     
     
         40 . An active matrix liquid-crystal display device, according to  claim 35 , wherein said interlayer insulating film is formed by conducting further the steps of: 
 forming organic film by applying thermosetting resin and then pre-baking it;    applying resist on the surface of the formed organic film, baking, exposing it;    forming a pattern of said organic film by wet-etching said organic film simultaneously with forming a resist pattern by developing said resist;    insolubilizing said organic film pattern to a developer by semi-hardening it by thermal cross-linking reaction;    dry-etching said base layer using said organic film pattern as a mask;    solubilizing said resist to the developer by radiating UV light onto at least one of the front and back surfaces of substrate;    removing said resist using said developer; and    completely hardening said organic film pattern by re-baking.    
     
     
         41 . An active matrix liquid-crystal display device, according to  claim 40 , wherein: 
 said resist is of positive-type resist using naphthoquinonediazo compound as a photosensitive agent, novolac resin as base resin and methylamine-system solvent, propyleneglycolmonoethyletheracetate solvent, 2-heptanone, ethyl-3-ethoxypropionate, or a mixed solvent of 2-heptanone and ethyl-3-ethoxypropionate as a solvent, and    said developing of resist, said wet-etching of organic film and said removing of resist are conducted using tetramethylammoniumhydroxide (TMAH) solution.    
     
     
         42 . An active matrix liquid-crystal display device, according to  claim 37 , wherein: 
 said organic film forming step is conducted by applying acrylic resin and resin including a photopolymerization initiator and pre-baking in the temperature range of 80 to 110° C., and    said organic film hardening step is conducted by re-baking in the temperature range of 220 to 260° C.    
     
     
         43 . An active matrix liquid-crystal display device, according to  claim 41 , wherein: 
 said organic film forming step is conducted by applying acrylic resin and resin including a photopolymerization initiator and pre-baking in the temperature range of 80 to 110° C., and    said organic film hardening step is conducted by re-baking in the temperature range of 220 to 260° C.    
     
     
         44 . An active matrix liquid-crystal display device, according to  claim 35 , wherein said interlayer insulating film is formed by conducting further the steps of: 
 forming organic film by applying UV-setting resin which is sensitive to light of i-line or a shorter wavelength and then pre-baking it;    applying resist on the surface of the formed organic film and baking it;    exposing it with light of g-line;    forming a pattern of said organic film by wet-etching said organic film simultaneously with forming a resist pattern by developing said resist;    radiating UV light onto at least one of the front and back surfaces of substrate, thereby insolubilizing said organic film pattern to a developer by semi-hardening said organic film pattern through cross-linking reaction and solubilizing said resist to the developer;    dry-etching said base layer using said organic film pattern as a mask;    removing said resist using said developer; and    completely hardening said organic film pattern by re-baking.    
     
     
         45 . An active matrix liquid-crystal display device, according to  claim 44 , wherein: 
 said resist is of g-line-photosensitive positive-type resist using naphthoquinonediazo compound as a photosensitive agent, novolac resin as base resin and methylamine-system solvent, propyleneglycolmonoethyletheracetate solvent as a solvent and    said developing of resist, said wet-etching of organic film and said removing of resist are conducted using tetramethylammoniumhydroxide (TMAH) solution.    
     
     
         46 . An active matrix liquid-crystal display device, according to  claim 37 , wherein: 
 said organic film forming step is conducted by applying a polymer of Cardo-type compound represented by structural formula [1] and a compound with epoxy group represented by structural formula [2], and resin including a photopolymerization initiator, and then pre-baking in the temperature range of 80 to 150° C., and    said organic film hardening step is conducted by re-baking in the temperature range of 230 to 280° C.    
     
     
         47 . An active matrix liquid-crystal display device, according to  claim 45 , wherein: 
 said organic film forming step is conducted by applying a polymer of Cardo-type compound represented by structural formula [1] and a compound with epoxy group represented by structural formula [2], and resin including a photopolymerization initiator, and then pre-baking in the temperature range of 80 to 150° C., and    said organic film hardening step is conducted by re-baking in the temperature range of 230 to 280° C.