Positive photoresist composition and process for forming resist pattern using same

Abstract

Disclosed are a positive photoresist composition including (A) an alkali-soluble resin, (B) a photosensitizer containing a quinonediazide ester of, e.g., bis[2,5-dimethyl-3-(2-hydroxy-5-methylbenzyl)-4-hydroxyphenyl]methane and (C) e.g., 2,6-bis(2,5-dimethyl-4-hydroxybenzyl)-4-methylphenol; and a process including the steps of coating the composition onto a 8 to 12-inch substrate, drying, exposing and developing the same. The composition which can form a pattern having a good shape whose dimensional changes are minimized in a wide range over surface of the substrate, particularly in processes using a large-diameter substrate, and the process for forming a resist pattern using the composition are provided.

What is claimed is:  
     
         1 . A positive photoresist composition comprising 
 (A) an alkali soluble resin,    (B) a photosensitizer containing a quinonediazide ester of a compound of the following formula (I):                          wherein each of R 1  and R 2  is independently a methyl group or an ethyl group, and    (C) at least one compound of phenol group-containing compounds giving an elution time in the range from 6 to 30 minutes in high performance liquid chromatography, said high performance liquid chromatography being conducted under the following conditions:    eluent: a mixed solvent of water:tetrahydrofuran:methanol=40:24:36 (by weight); column: 4.6 mm (diameter)×150 mm (length) containing 5 μm silica gel as a filler (carbon content being about 15%); column temperature: 45.0° C.; supply rate of eluent: 0.700 ml/min.    
     
     
         2 . The composition according to  claim 1 , wherein said compound represented by the formula (I) is a compound of the following formula (Ia):  
       
         
           
           
               
               
           
         
       
     
     
         3 . The composition according to  claim 1 , wherein said compound represented by the formula (I) is a compound of the following formula (Ib):  
       
         
           
           
               
               
           
         
       
     
     
         4 . The composition according to  claim 1 , wherein the content of Ingredient (C) ranges from 5% to 50% by weight relative to Ingredient (A).  
     
     
         5 . The composition according to  claim 1 , wherein said phenol group-containing compound, Ingredient (C), is at least one compound selected from the group consisting of the following compounds (c1) through (c6):  
       
         
           
           
               
               
           
         
       
     
     
         6 . A process for forming a resist pattern comprising the steps of: 
 (1) coating the positive photoresist composition of  claim 1  onto a substrate having a diameter ranging from 8 to 12 inches, and drying the coated substrate to form a resist film,    (2) subjecting said resist film to selective exposure though a mask,    (3) heating said resist film, and    (4) removing the resist film at exposed positions by an aqueous alkali solution.