ENVIRONMENTAL FRIENDLY PHOTOACID GENERATORS (PAGs) WITH NO PERFLUOROOCTYL SULFONATES

Abstract

Novel classes of ionic photoacid generator (PAGs) compounds having relatively environmentally friendly anions with no perfluorooctyl sulfonate (no-PFOS) are provided and photoresist composition that comprise such compounds. The new PAGs produce a photoacid having a short or no perfluoro alkyl chain (i.e., no-PFOS) attached to a variety of functional groups. The PAGs of the invention are useful as photoactive component in the chemically amplified resist compositions used for microfabrication.

1 . A photoacid generator for a chemical amplification type resist composition comprising an onium salt of formula (I): 
       
         
           
           
               
               
           
         
       
       wherein
 R 0  is a substituted or unsubstituted, straight, branched or cyclic alkyl group of 1 to 10 carbon atoms or a substituted or unsubstituted aryl group of 6 to 14 carbon atoms; 
 M is a compound or atom capable of providing an onium cation; 
 “a” is 2 or 3; 
 n is 1 to 4; 
 R 1  is —CH 2 CH 2 CH 2 OH, p 13  CH 2 CH 2 OH, —OCH 2 CH 3 , —OC(CH 3 ) 3 , —CH 2 CH 2 OCH 3 , —CH 2 CH 2 Cl, —CH═CH 2 , —OCF 2 CF 2 I, —CH 2 CH(Br)CH 3 , 
 
       
         
           
           
               
               
           
         
         R 10  and R 12  are each independently H, Br, CN, —OCH 3 , —COOH, —NO 2 , or —OCOCH 3 . 
       
     
     
         2 . A chemical amplification type resist composition comprising:
 a) a resin which changes its solubility in an alkaline developer under the action of an acid;   b) the photoacid generator of  claim 1  which generates an acid upon exposure to radiation;   c) optionally a basic compound; and   d) optionally a compound capable of generating an acid upon exposure to radiation, other than the photoacid generator of formula (I).   
     
     
         3 . A process for forming a pattern, comprising:
 a) applying the resist composition of  claim 2  onto a substrate to form a coating;   b) heat treating the coating and exposing the coating to high energy radiation or electron beam through a photo-mask; and   c) optionally heat treating the exposed coating, and developing the coating with a developer.   
     
     
         4 . The photoacid generator of  claim 1 , wherein M is a sulfur or iodine atom and “a” is 3 when M is sulfur and “a” is 2 when M is iodine. 
     
     
         5 . The photoacid generator of  claim 1 , wherein the onium salt is an onium salt of formula (VI): 
       
         
           
           
               
               
           
         
       
       wherein
 M is a sulfur or iodine atom, and “a” is 3 when M is sulfur and “a” is 2 when M is iodine; n is 1 to 4; and 
 R 1  is —OCH 2 CH 3 , —OC(CH 3 ) 3 , —CH 2 CH 2 OCH 3 , or 
 
       
         
           
           
               
               
           
         
       
     
     
         6 . A chemical amplification type resist composition comprising:
 a) a resin which changes its solubility in an alkaline developer under the action of an acid, and   b) the photoacid generator of  claim 5  which generates an acid upon exposure to radiation.   
     
     
         7 . A process for forming a pattern, comprising:
 a) applying the resist composition of  claim 6  onto a substrate to form a coating;   b) heat treating the coating and exposing the coating to high energy radiation or electron beam through a photo-mask; and   c) optionally heat treating the exposed coating, and developing the coating with a developer.   
     
     
         8 . A photoacid generator for a chemical amplification type resist composition comprising an onium salt of formula (VII): 
       
         
           
           
               
               
           
         
       
       wherein
 M is a sulfur or iodine atom; 
 “a” is 3 when M is sulfur and “a” is 2 when M is iodine; and 
 R 2  is Cl, —CH 2 CH 2 OH, —CH 2 CH 2 CH 2 OH, —CH 2 CH 2 Cl, or —CH═CH 2 . 
 
     
     
         9 . A chemical amplification type resist composition comprising:
 a) a resin which changes its solubility in an alkaline developer under the action of an acid, and   b) the photoacid generator of  claim 8  which generates an acid upon exposure to radiation.   
     
     
         10 . A process for forming a pattern, comprising:
 a) applying the resist composition of  claim 9  onto a substrate to form a coating;   b) heat treating the coating and exposing the coating to high energy radiation or electron beam through a photo-mask; and   c) optionally heat treating the exposed coating, and developing the coating with a developer.   
     
     
         11 . A photoacid generator for a chemical amplification type resist composition comprising an onium salt of formula (II): 
       
         
           
           
               
               
           
         
       
       wherein
 R 0  is a substituted or unsubstituted, straight, branched or cyclic alkyl group of 1 to 10 carbon atoms or a substituted or unsubstituted aryl group of 6 to 14 carbon atoms; 
 M is a compound or atom capable of providing an onium cation; 
 “a” is 2 or 3; and 
 R 3  is F, Cl, or CH 3 . 
 
     
     
         12 . The photoacid generator of  claim 11 , wherein M is a sulfur or iodine atom, and “a” is 3 when M is sulfur and “a” is 2 when M is iodine. 
     
     
         13 . A chemical amplification type resist composition comprising:
 a) a resin which changes its solubility in an alkaline developer under the action of an acid;   b) the photoacid generator of  claim 11  which generates an acid upon exposure to radiation;   c) optionally a basic compound; and   d) optionally a compound capable of generating an acid upon exposure to radiation, other than the photoacid generator of formula (II).   
     
     
         14 . A process for forming a pattern, comprising:
 a) applying the resist composition of  claim 13  onto a substrate to form a coating;   b) heat treating the coating and exposing the coating to high energy radiation or electron beam through a photo-mask; and   c) optionally heat treating the exposed coating, and developing the coating with a developer.   
     
     
         15 . A photoacid generator for a chemical amplification type resist composition comprising an onium salt of formula (III): 
       
         
           
           
               
               
           
         
       
       wherein
 R 0  is a substituted or unsubstituted, straight, branched or cyclic alkyl group of 1 to 10 carbon atoms or a substituted or unsubstituted aryl group of 6 to 14 carbon atoms; 
 M is a compound or atom capable of providing an onium cation; 
 “a” is 2 or 3; and 
 R 4  is H, F, Br, —OCH 3 , —COOH, —CN, or —OCOCH 3 ; 
 
     
     
         16 . The photoacid generator of  claim 15 , wherein M is a sulfur or iodine atom, and “a” is equal to 3 when M is sulfur and equal to 2 when M is iodine. 
     
     
         17 . A chemical amplification type resist composition comprising:
 a) a resin which changes its solubility in an alkaline developer under the action of an acid;   b) the photoacid generator of  claim 15  which generates an acid upon exposure to radiation; and   c) optionally a basic compound; and   d) optionally a compound capable of generating an acid upon exposure to radiation, other than the photoacid generator of formula (III).   
     
     
         18 . A process for forming a pattern, comprising:
 a) applying the resist composition of  claim 17  onto a substrate to form a coating;   b) heat treating the coating and exposing the coating to high energy radiation or electron beam through a photo-mask; and   c) optionally heat treating the exposed coating, and developing the coating with a developer.   
     
     
         19 . A photoacid generator for a chemical amplification type resist composition comprising an onium salt of formula (IV): 
       
         
           
           
               
               
           
         
       
       wherein
 R 0  is a substituted or unsubstituted, straight, branched or cyclic alkyl group of 1 to 10 carbon atoms or a substituted or unsubstituted aryl group of 6 to 14 carbon atoms; 
 M is a compound or atom capable of providing an onium cation; 
 “a” is 2 or 3; and 
 Z is F and R 5  is H or CF 3 ; or 
 Z is CF 3  and R 5  is H or F. 
 
     
     
         20 . The photoacid generator of  claim 19 , wherein M is a sulfur or iodine atom, and “a” is equal to 3 when M is sulfur and equal to 2 when M is iodine. 
     
     
         21 . A chemical amplification type resist composition comprising:
 a) a resin which changes its solubility in an alkaline developer under the action of an acid;   b) the photoacid generator of  claim 19  which generates an acid upon exposure to radiation; and   c) optionally a basic compound; and   d) optionally a compound capable of generating an acid upon exposure to radiation, other than the photoacid generator of formula (IV).   
     
     
         22 . A process for forming a pattern, comprising:
 a) applying the resist composition of  claim 21  onto a substrate to form a coating;   b) heat treating the coating and exposing the coating to high energy radiation or electron beam through a photo-mask; and   c) optionally heat treating the exposed coating, and developing the coating with a developer.   
     
     
         23 . A photoacid generator for a chemical amplification type resist composition comprising an onium salt of formula (V): 
       
         
           
           
               
               
           
         
       
       wherein
 R 0  is a substituted or unsubstituted, straight, branched or cyclic alkyl group of 1 to 10 carbon atoms or a substituted or unsubstituted aryl group of 6 to 14 carbon atoms; 
 M is a compound or atom capable of providing an onium cation; 
 “a” is 2 or 3; and 
 R 6  is H, Br, —OCH 3 , —COOH, —CN, or —OCOCH 3 . 
 
     
     
         24 . The photoacid generator of  claim 23 , wherein M is a sulfur or iodine atom, and “a” is equal to 3 when M is sulfur and equal to 2 when M is iodine. 
     
     
         25 . A chemical amplification type resist composition comprising:
 a) a resin which changes its solubility in an alkaline developer under the action of an acid;   b) the photoacid generator of  claim 23  which generates an acid upon exposure to radiation; and   c) optionally a basic compound; and   d) optionally a compound capable of generating an acid upon exposure to radiation, other than the photoacid generator of formula (V).   
     
     
         26 . A process for forming a pattern, comprising:
 a) applying the resist composition of  claim 25  onto a substrate to form a coating;   b) heat treating the coating and exposing the coating to high energy radiation or electron beam through a photo-mask; and   c) optionally heat treating the exposed coating, and developing the coating with a developer.