Novel ester compounds polymers, resist compositions and patterning process

Abstract

An ester compound of the following formula (1) is provided. R 1 is H, methyl or CH 2 CO 2 R 3 , R 2 is H, methyl or CO 2 R 3 , R 3 is C 1 -C 15 alkyl, k is 0 or 1, Z is a divalent C 2 -C 20 hydrocarbon group which forms a single ring or bridged ring with the carbon atom and which may contain a hetero atom, m is 0 or 1, n is 0, 1, 2 or 3, and 2m+n=2 or 3. A resist composition comprising as the base resin a polymer resulting from the ester compound is sensitive to high-energy radiation, has excellent sensitivity, resolution, and etching resistance, and is suited for micropatterning using electron-beams or deep-UV.

1 . An ester compound of the following general formula (1):  
       
         
           
           
               
               
           
         
       
       wherein R 1  is hydrogen, methyl or CH 2 CO 2 R 3 , R 2  is hydrogen, methyl or CO 2 R 3 , R 3  is a straight, branched or cyclic alkyl group of 1 to 15 carbon atoms, k is 0 or 1, Z is a divalent hydrocarbon group of 2 to 20 carbon atoms which forms a single ring or bridged ring with the carbon atom and which may contain a hetero atom, m is 0 or 1, n is 0, 1, 2 or 3, and 2 m+n is 2 or 3.  
     
     
         2 . A polymer comprising recurring units of the following general formula (1a-1) and/or (1a-2) derived from an ester compound of the general formula (1), and having a weight average molecular weight of 1,000 to 500,000,  
       
         
           
           
               
               
           
         
       
       wherein R 1 , R 2 , Z, k, m and n are as defined above.  
     
     
         3 . The polymer of  claim 2  further comprising recurring units of at least one of the following formulas (2a) to (10a):  
       
         
           
           
               
               
           
         
         
           
           
               
               
           
         
       
       wherein R 1 , R 2  and k are as defined above, 
 R 4  is hydrogen or a carboxyl or hydroxyl-containing monovalent hydrocarbon group of 1 to 15 carbon atoms,  
 at least one of R 5  to R 8  is a carboxyl or hydroxyl-containing monovalent hydrocarbon group of 1 to 15 carbon atoms, and the remainders are independently hydrogen or a straight, branched or cyclic alkyl group of 1 to 15 carbon atoms, or R 5  to R 8 , taken together, may form a ring, and when they form a ring, at least one of R 5  to R 8  is a carboxyl or hydroxyl-containing divalent hydrocarbon group of 1 to 15 carbon atoms, and the remainders are independently a single bond or a straight, branched or cyclic alkylene group of 1 to 15 carbon atoms,  
 R 9  is a monovalent hydrocarbon group of 3 to 15 carbon atoms containing a —CO 2 — partial structure,  
 at least one of R 10  to R 13  is a monovalent hydrocarbon group of 2 to 15 carbon atoms containing a —CO 2 — partial structure, and the remainders are independently hydrogen or a straight, branched or cyclic alkyl group of 1 to 15 carbon atoms, or R 10  to R 13 , taken together, may form a ring, and when they form a ring, at least one of R 10  to R 13  is a divalent hydrocarbon group of 1 to 15 carbon atoms containing a —CO 2 — partial structure, and the remainders are independently a single bond or a straight, branched or cyclic alkylene group of 1 to 15 carbon atoms,  
 R 14  is a polycyclic hydrocarbon group of 7 to 15 carbon atoms or an alkyl group containing such a polycyclic hydrocarbon group,  
 R 15  is an acid labile group,  
 X is —CH 2 — or —O—, and  
 Y is —O— or —(NR 16 )— wherein R 16  is hydrogen or a straight, branched or cyclic alkyl group of 1 to 15 carbon atoms.  
 
     
     
         4 . A method for preparing a polymer comprising the step of effecting radical polymerization, anionic polymerization or coordination polymerization between an ester compound of the general formula (1) and another compound having a carbon-to-carbon double bond.  
     
     
         5 . A resist composition comprising the polymer of  claim 2  or  3 .  
     
     
         6 . A resist composition comprising the polymer of  claim 2  or  3 , a photoacid generator, and an organic solvent.  
     
     
         7 . A process for forming a resist pattern comprising the steps of: 
 applying the resist composition of  claim 5  or  6  onto a substrate to form a coating,    heat treating the coating and then exposing it to high-energy radiation or electron beams through a photo mask, and    optionally heat treating the exposed coating and developing it with a developer.