USRE38980EExpiredUtility

Photoresist compositions

60
Assignee: SHIPLEY CO LLCPriority: Aug 28, 1997Filed: Mar 14, 2002Granted: Feb 14, 2006
Est. expiryAug 28, 2017(expired)· nominal 20-yr term from priority
Inventors:James W. ThackerayJames F. CameronRoger F. Sinta
G03F 7/11G03F 7/0233G03F 7/0226G03F 7/0236G03F 7/091G03F 7/0045G03F 7/0392G03F 7/039G03F 7/38
60
PatentIndex Score
4
Cited by
17
References
32
Claims

Abstract

The invention provides photoresist compositions comprising a resin binder having acid labile blocking groups requiring an activation energy in excess of 20 Kcal/mol. for deblocking, a photoacid generator capable of generating a halogenated sulfonic acid upon photolysis and optionally, a base additive. It has been found that linewidth variation is substantially reduced when using the halogenated sulfonic acid generator in a process involving a high temperature post exposure bake.

Claims

exact text as granted — not AI-modified
1. A process for formation of an image in a photoresist film, said process comprising:
 (a) providing a positive working photoresist composition comprising an alkali soluble resin substituted with an acid labile blocking group that requires an activation energy of at least 20 Kcal/mol for deblocking, and a photoacid generating compound that undergoes photolysis when exposed to a pattern of activating radiation at a wavelength of 350 nm or less to yield a sulfonic acid having a strong electron withdrawing group, and wherein the alkali soluble resin conforms to the formula: 
                 
   
       where x′ is greater than zero and represents the mole fraction of the hydroxystyrene units and y′ is greater than zero and represents the mole fraction of the acrylate units, the hydroxyl group on the hydroxystyrene may be present at either the ortho, meta or para positions throughout the copolymer, R 7  is substituted or unsubstituted alkyl having 1 to about 18 carbon atoms, R′ and R″ are independently halogen, substituted or unsubstituted alkyl having from 1 to about 8 carbon atoms, substituted or unsubstituted alkoxy having from 1 to about 8 carbon atoms, substituted or unsubstituted alkenyl having from 2 to about 8 carbon atoms, substituted or unsubstituted alkylthio having from 1 to about 8 carbon atoms, cyano or nitro; and m and p are independent 0 to 5;
 (b) exposing said photoresist to deep ultraviolet radiation to deblock the acid labile group, baking said exposed photoresist film at a temperature in excess of 120° C.,  
 (c) developing said photoresist with an aqueous alkaline solution.  
 
     
     
       2. The process of  claim 1  where the bake temperature is in excess of 140° C. 
     
     
       3. The process of  claim 1  where the photoacid generator is one capable of generating an acid of the formula:
   X a RSO 3   −     
       where R is an organic radical having from 1 to 18 carbon atoms, X is a strong electron withdrawing group and a is a whole number equal to 1 or 2. 
     
     
       4. The process of  claim 3  where the pK a  of the liberated acid does not exceed 0. 
     
     
       5. The process of  claim 3  where the pK a  varies between −5 and −15. 
     
     
       6. The process of  claim 3  where the strong electron withdrawing group is selected from the group consisting of halo, nitro, and cyano. 
     
     
       7. The process of  claim 3  where the strong electron withdrawing group is perfluoroalkyl having from 1 to 18 carbon atoms. 
     
     
       8. The process of  claim 7  where the strong electron withdrawing group is trifluoromethyl. 
     
     
       9. The process of  claim 1  where the acid labile blocking group requires an activation energy of from 25 to 40 Kcal/mol for deblocking. 
     
     
       10. The process of  claim 1  where the acid is selected from the group consisting of perfluorooctane sulfonic acid and 2-trifluoromethylbenzene sulfonic acid. 
     
     
       11. The process of  claim 1  where the photoresist contains a base having a pK a  of at least 9. 
     
     
       12. The process of  claim 11  where the pK a  varies between 11 and 15. 
     
     
       13. The process of  claim 11  where the base conforms to the formula N(R′) 4 A where R′ is substituted or unsubstituted alkyl having from 1 to about 12 carbon atoms or substituted or unsubstituted aryl, A is a counter anion of a member selected from the group consisting of halide, a substituted or unsubstituted hydroxyalkanoyl having from 1 to 18 carbon atoms and substituted or unsubstituted sulfonate. 
     
     
       14. The process of  claim 13  where the counter anion is sulfonate. 
     
     
       15. The process of  claim 1  wherein the photoresist is exposed to radiation having a wavelength of about 248 nm. 
     
     
       16. A process for formation of an image in a photoresist film, said process comprising:
 ( a )  providing a positive working photoresist composition comprising an alkali soluble resin substituted with an acid labile blocking group that requires an activation energy of at least  20  Kcal/mol for deblocking, and a photoacid generating compound that undergoes photolysis when exposed to a pattern of activating radiation at a wavelength of  350  nm or less to yield a sulfonic acid having a strong electron withdrawing group, and wherein the alkali soluble resin conforms to the formula:  
                 
   
       
         where x is from about  10  to  90  percent, y is from about  1  to  75  percent, and z is from  1  to  75  percent of the mole fraction, the hydroxyl group on the hydroxystyrene may be present at either the ortho, meta or para positions throughout the copolymer, R is substituted or unsubstituted alkyl having  1  to  10  carbon atoms, R 
         1  
         and R 
         2  
         are independently halogen, substituted or unsubstituted alkyl having from  1  to  8  carbon atoms, substituted or unsubstituted alkoxy having from  1  to  8  carbon atoms, substituted or unsubstituted alkenyl having  2  to  8  carbon atoms, substituted or unsubstituted alkylthio having from  1  to  8  carbon atoms, cyano, and nitro; and m is an integer of from  0  to  5  and p is an integer of from  0  to  5 ; and R 
         3 
         , R 
         4 
         , and R 
         5  
         are hydrogen;  
         ( b )  exposing said photoresist to deep ultraviolet radiation to deblock the acid labile group, baking said exposed photoresist film at a temperature in excess of  120 ° C.; and    
         ( c )  developing said photoresist with an aqueous alkaline solution.   
       
     
     
       17. The process of  claim 16  wherein x is from about  20  to  90  percent of the mole fraction. 
     
     
       18. The process of  claim 16  wherein y is from about  2  to  60  percent of the mole fraction. 
     
     
       19. The process of  claim 16  wherein z is from about  2  to  60  percent of the mole fraction. 
     
     
       20. The process of  claim 16  where the bake temperature is in excess of  140 ° C. 
     
     
       21. The process of  claim 16  where the photoacid generator is one capable of generating an acid of the formula:
     X   a   RSO   3   −     
       
         where R is an organic radical having from  1  to  18  carbon atoms, X is a strong electron withdrawing group and a is a whole number preferably equal to  1  or  2 . 
       
     
     
       22. The process of  claim 21  where the pK a    varies between − 5  and − 15 .   
     
     
       23. The process of  claim 21  where the strong electron withdrawing group is selected from the group consisting of halo, nitro, cyano. 
     
     
       24. The process of  claim 23  where the strong electron withdrawing group is perfluoroalkyl having from  1  to  18  carbon atoms. 
     
     
       25. The process of  claim 24  where the strong electron withdrawing group is trifluoromethyl. 
     
     
       26. The process of  claim 16  where the acid labile blocking group requires an activation energy of from  25  to  40  Kcal/mol for deblocking. 
     
     
       27. The process of  claim 16  where the acid is selected from the group consisting of perfluorooctane sulfonic acid and  2 - trifluoromethylbenzene sulfonic acid.   
     
     
       28. The process of  claim 16  where the photoresist contains a base having a pK a    of at least  9 .   
     
     
       29. The process of  claim 28  where the pK a    varies between  11  and  15 .   
     
     
       30. The process of  claim 28  where the base conforms to the formula N( R′ ) A   4    where R′ is substituted or unsubstituted alkyl preferably having from  1  to about  12  carbon atoms or substituted or unsubstituted aryl, A is a counter anion of a member selected from the group consisting of halide, a substituted or unsubstituted hydroxyalkanoyl having from  1  to  18  carbon atoms and substituted or unsubstituted sulfonate.   
     
     
       31. The process of  claim 30  where the counter anion is sulfonate. 
     
     
       32. The process of  claim 16  where the photoresist is exposed to radiation having a wavelength of about  248  nm.

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