Photoresist composition for deep ultraviolet lithography

Abstract

The present invention relates to a photoresist composition comprising a photoacid generator and at least one novel polymer comprising at least one unit as described by structure 1, where, either (i) R1 is an aliphatic cyclic unit of a polymer, R2 is selected from H, F, (C1-C8)alkyl, (C1-C8)fluoroalkyl, cycloalkyl, cyclofluoroalkyl, and (CR3R4)p(CO)OR5, and R f is selected from F, H, (C1-C8)alkyl, or a fully or partially fluorinated alkyl, and cyclofluoroalkyl, or (ii) R1 and R2 combine to form an aliphatic cyclic unit of a polymer, and R f is selected from F, H, (C1-C8)alkyl and a fully or partially fluorinated alkyl, and cyclofluoroalkyl, or (ii) R1 and R f combine to form an aliphatic cyclic unit of a polymer, and R2 is selected from H, F, (C1-C8)alkyl, (C1-C8)fluoroalkyl, cycloalkyl, cyclofluoroalkyl, and (CR3R4)p(CO)OR5; and, R3 and R4 are independently H, F, (C1-C8)alkyl, (C1-C8)fluoroalkyl, cycloalkyl, cyclofluoroalkyl, (CR3R4)p(CO)OR5, R3 and R4 may combine to form an alkylspirocyclic or a fluoroalkylspirocyclic group, X is selected from (C1-C8)alkylene, (C1-C8)fluoroalkylene, O(C1-C8)alkylene, O(C1-C8)fluoroalkylene, cycloalkyl and fluorinatedcycloalkyl, R5 is H or an acid labile group, m=0-1, and p=1-4. The invention also relates to a process for imaging the photoresist composition of the present invention.

1 . A photoresist composition comprising a photoacid generator and at least one novel polymer comprising at least one unit as described by structure 1,  
       
         
           
           
               
               
           
         
       
       where, either 
 (i) R1 is an aliphatic cyclic unit of a polymer, R2 is selected from H, F, (C1-C8)alkyl, (C1-C8)fluoroalkyl, cycloalkyl, cyclofluoroalkyl, and (CR3R4)p(CO)OR5, and R f  is selected from F, H, (C1-C8)alkyl, or a fully or partially fluorinated alkyl, and cyclofluoroalkyl, or  
 (ii) R1 and R2 combine to form an aliphatic cyclic unit of a polymer, and rf is selected from F, H, (C1-C8)alkyl and a fully or partially fluorinated alkyl, and cyclofluoroalkyl, or  
 (ii) R1 and R f  combine to form an aliphatic cyclic unit of a polymer, and R2 is selected from H, F, (C1-C8)alkyl, (C1-C8)fluoroalkyl, cycloalkyl, cyclofluoroalkyl, and (CR3R4)p(CO)OR5; and,  
 R3 and R4 are independently H, F, (C1-C8)alkyl, (C1-C8)fluoroalkyl, cycloalkyl, cyclofluoroalkyl, (CR3R4)p(CO)OR5, R3 and R4 may combine to form an alkylspirocyclic or a fluoroalkylspirocyclic group,  
 x is selected from (C1-C8)alkylene, (C1-c8)fluoroalkylene, O(C1-C8)alkylene, O(C1-C8)fluoroalkylene, cycloalkyl and fluorinatedcycloalkyl,  
 R5 is H or an acid labile group, m=0-1, and p=1-4.  
 
     
     
         2 . The composition according to  claim 1 , where the polymer comprises an aliphatic cyclic fluoroalcohol unit functionalized with an alkyloxycarbonylalkyl group.  
     
     
         3 . The composition according to  claim 1 , where the cyclic unit is an aliphatic multicyclic unit or an aliphatic monocyclic unit.  
     
     
         4 . The composition according to  claim 3 , where the multicyclic unit is selected from those derived from the following monomers,  
       
         
           
           
               
               
           
         
         where, in the above structures, R1-R7 are independently H, F, (C1-C8)alkyl, (C 1 -C8)fluoroalkyl, etc but at least one of R1-R6 has the pendant oxyAOCA functionality described in structure 1, or an alcohol functionality which can be capped to give the unit of structure 1.  
       
     
     
         5 . The composition according to  claim 3 , where the multicyclic unit is selected from those derived from the following monomers,  
       
         
           
           
               
               
           
         
         
           
           
               
               
           
         
       
     
     
         6 . The composition according to  claim 3 , where the monocyclic unit is derived from functionalizing fluoroalcohols with an AOCA group, and where the fluoroalcohols are selected from  
     
     
         7 . The composition according to  claim 6 , where the fluoroalcohols are selected from,  
       
         
           
           
               
               
           
         
         Rf=fluoroalkyl group C 1 -C 8  Y=alkyl or fluoroalkyl spacer group C 1 -C 8    
         Ra, Rb, Rc, Rd, Re, Rg=alkyl, X═CF 2 , O fluoroalkyl or fluorocycloalkyl,  
         Also, Ra-Re and Rg can be substituted with alkyl, fluoroalkyl, cycloakyl, fluorocycloalkyl or with a spirofluoroalkyl or spiroalkyl subsituent  
       
     
     
         8 . The composition of  claim 2 , where the alkyloxycarbonylalkyl group is selected from t-butyloxycarbonylmethyl, methyl-adamantyloxycarbonylmethyl, t-amyloxycarbonylmethyl, methyl-Inorbornyloxycarbonylmethyl, t-butyloxycarbonyl propyl and t-butyloxycarbonyldifluorobutyl.  
     
     
         9 . The composition of  claim 1 , where the acid labile group is selected from secondary and tertiary alkyls (up to 20 carbon atoms), acetals and ketals, trimethylsilyl, β-trimethylsilyl substituted alkyls, tetrahydrofuranyl, tetrahydropyranyl, substituted or unsubstituted methoxymethoxycarbonyl, and β-trialkylsilylalkyl.  
     
     
         10 . The composition of  claim 1 , where the polymer is selected from poly(bicyclo[2.2.1]hept-5-en-2-yl)-1,1,1-trifluoro-2-(trifluoromethyl)propan-2-ol), poly(1,1,2,3,3-pentafluoro-4-trifluoromethyl-4-hydroxy-1,6-heptadiene and poly(1,1,2,3,3-pentafluoro-4-trifluoroalkyl-4-hydroxy-1,6-heptadiene).  
     
     
         11 . The composition of  claim 1 , where the polymer comprises a mixture of polymers comprising monocyclic units and polymers comprising multicyclic units.  
     
     
         12 . The composition of  claim 11 , where the mixture is poly(bicyclo[2.2.1]hept-5-en-2-yl)-1,1,1-trifluoro-2-(trifluoromethyl)propan-2-ol) with poly(1,1,2,3,3-pentafluoro 4-trifluoromethyl-4-hydroxy-1,6-heptadiene).  
     
     
         13 . The composition of  claim 1 , where the composition further comprises a dissolution inhibitor.  
     
     
         14 . The composition of  claim 1 , where the composition further comprises a base.  
     
     
         15 . The composition of  claim 1 , where the photoacid generator is selected from diazonium salts, iodonium salts, sulfonium salts, triazines, oxazoles, oxadiazoles, thiazoles, substituted 2-pyrones and phenolic sulfonic esters.  
     
     
         16 . A process for imaging a photoresist composition comprising the steps of: 
 a) forming on a substrate a photoresist coating from the photoresist composition of  claim 1;     b) image-wise exposing the photoresist coating;    c) postexposure baking the photoresist coating; and    d) developing the photoresist coating with an aqueous alkaline solution.    
     
     
         17 . The process of  claim 16 , where the image-wise exposure wavelength is below 200 nm.  
     
     
         18 . The process according to  claim 16 , where the aqueous alkaline solution comprises tetramethylammonium hydroxide.  
     
     
         19 . The process according to  claim 16 , where the aqueous alkaline solution further comprises a surfactant.