Resist compositions including thermal crosslinking agents

Abstract

A method for forming a fine pattern in a semiconductor substrate, by coating a target layer to be etched on a semiconductor substrate with a resist composition including at least one compound capable of forming a photoresist pattern by a photolithography process, and a free radical initiator. The free radical initiator is capable of being decomposed by a thermal process at a temperature equal to or higher than the glass transition temperature of the at least one compound. A lithography process is performed on the resist compound layer to form a photoresist pattern. The resist compound layer having the photoresist pattern formed therein is heated to a temperature equal to or higher than the glass transition temperature of the at least one compound, and wherein a partial cross-linking reaction in the resist composition occurs.

1 . A resist composition comprising: 
 at least one compound capable of forming a photoresist pattern by a photolithography process; and    a thermal crosslinking agent capable of causing a partial cross-linking reaction in the resist composition in response to a temperature equal to or higher than the glass transition temperature or the softening temperature of the at least one compound and in the absence of UltraViolet (UV) radiation.    
     
     
         2 . The resist composition of  claim 1 , wherein said at least one compound is selected from the group consisting of a Novolak resin, a diazonaphthoquinone compound, and mixtures thereof.  
     
     
         3 . The resist composition of  claim 1 , wherein said resist composition is a chemically amplified resist composition comprising a photo acid generator.  
     
     
         4 . The resist composition of  claim 1 , wherein said thermal crosslinking agent is a vinylether derivative.  
     
     
         5 . The resist composition of  claim 4 , wherein the vinylether derivative is represented by the formula:  
         R—(—OCH═CH 2 ) x    
       wherein x is an integer ranging from 2 to 4; and R is a C 1  to C 20  hydrocarbon or an oligomer having a weight average molecular weight ranging from about 500 to about 5000.  
     
     
         6 . The resist composition of  claim 1 , wherein said thermal crosslinking agent is present in an amount from about 1 to about 20 percent based on the weight of polymer present in said at least one compound.  
     
     
         7 . The resist composition of  claim 1 , wherein said thermal crosslinking agent is selected from the group consisting of 1,4-butandiol divinylether, tri(ethyleneglycol)divinylether, trimethyolpropane trivinyl ether, 1,4-cyclohexanedimethanol divinyl ether, and mixtures thereof.  
     
     
         8 . The resist composition of  claim 1 , wherein said thermal crosslinking agent is a free radical initiator.  
     
     
         9 . The resist composition of  claim 8 , wherein the free radical initiator is present in an amount of from about 1 to about 15 percent based on the weight of polymer present in said at least one compound.  
     
     
         10 . The resist composition of  claim 8 , wherein the resist composition comprises from about 3 to about 15 percent by weight of said free radical initiator based on the weight of the solids in the resist composition.  
     
     
         11 . The resist composition of  claim 8 , wherein said free radical initiator is selected from the group consisting of acyl peroxides, alkyl peroxides, peresters, hydroperoxides, azo compounds, and mixtures thereof.  
     
     
         12 . The resist composition of  claim 8 , wherein said free radical initiator is selected from the group consisting of benzoyl peroxide, dicumyl peroxide, di-tert-butyl peroxide, cumyl hydroperoxide, azobis (isobutyronitrile), and mixtures thereof.  
     
     
         13 . The resist composition of  claim 1 , wherein said resist composition further comprises an organic base.  
     
     
         14 . The resist compound of  claim 13 , wherein the organic base is present in an amount of from about 0.01 to about 2.0 percent by weight based on the at least one compound.  
     
     
         15 . The resist compound of  claim 13 , wherein the organic base is one selected from the group consisting of N,N′-dimethylaniline, N,N′-diethylaniline, triethylamine, triisobutylamine, diethanolamine, triethanolamine, and mixtures thereof.