(meth)acrylate derivative, polymer and photoresist composition having lactone structure, and method for forming pattern by using it

Abstract

A photoresist material for lithography using a light of 220 nm or less which comprises at least a polymer represented by the following formula (2) and a photo-acid generator for generating an acid by exposure: wherein R 1 , R 2 , R 3 and R 5 are each a hydrogen atom or a methyl group; R 4 is an acid-labile group or one of a specified subset of alicyclic hydrocarbon groups, alicyclic hydrocarbon groups, or hydrocarbon groups; R 6 is a hydrogen atom or one of a specified subset of hydrocarbon groups or alicyclic hydrocarbon groups; x, y and z are optional values which meet x+y+z=1, 0<x≦1, 0≦y<1 and 0≦z<1. Also disclosed is a resin having a (meth)acrylate unit of an alicyclic lactone structure represented by the formula (3): wherein R 8 is a hydrogen atom or a methyl group, and R 9 is one of a specified subset of hydrocarbon groups.

1 . A method for forming a polymer comprising
 polymerizing a (meth)acrylate derivative represented by the formula (1) or copolymerizing the (meth)acrylate derivative represented by the formula (1) with another polymerizable compound:   
       
         
           
           
               
               
           
         
         wherein R 1  and R 2  are each a hydrogen atom or a methyl group. 
       
     
     
         2 . The method for forming a polymer according to  claim 1 , wherein the polymer is represented by the formula (2): 
       
         
           
           
               
               
           
         
         wherein R 1 , R 2 , R 3  and R 5  are each a hydrogen atom or a methyl group; R 4  is an acid-labile group, an alicyclic hydrocarbon group having 7 to 13 carbon atoms, which has an acid-labile group, an alicyclic hydrocarbon group having 7 to 13 carbon atoms, which has a carboxyl group, or a hydrocarbon group having 3 to 13 carbon atoms, which has an epoxy group; R 6  is a hydrogen atom, a hydrocarbon group having 1 to 12 carbon atoms, or an alicyclic hydrocarbon group having 7 to 13 carbon atoms, which has a carboxyl group; and x, y and z are optional values which meet x+y+z=1, 0<x≦1, 0≦y<1 and 0≦z<1. 
       
     
     
         3 . The method for forming a polymer according to  claim 2 , wherein the polymer has a weight-average molecular weight of 2000 to 200000. 
     
     
         4 . The method for forming a polymer according to  claim 1 , polymerizing method is radical polymerization.