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

Abstract

There are here disclosed 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, 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; x, y and z are optional values which meet x+y+z=1, 0<x≦1, 0≦y<1 and 0≦z<1; and a weight-average molecular weight of the polymer is in the range of 2000 to 200000, and 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 a hydrocarbon group of 7 to 16 carbon atoms having an alicyclic lactone structure.

1 - 4 . (canceled) 
     
     
         5 . A method for forming a polymer comprising
 polymerizing a (meth)acrylate derivative having an alicyclic lactone structure which is represented by formula (4) or copolymerizing the (meth)acrylate derivative represented by formula (4) with, another polymerizable compound:   
       
         
           
           
               
               
           
         
         wherein R 8  is a hydrogen atom or a methyl group; and R 9  is a hydrocarbon group of 7 to 16 carbon atoms having an alicyclic lactone structure. 
       
     
     
         6 . The method for forming a polymer according to claim  1 , comprising polymerizing at least two different (meth)acrylate derivatives of formula (4). 
     
     
         7 . The method for forming a polymer according to claim  1 , wherein the polymerizing method is radical polymerization.