Photosensitive polyimide precursor and its use for pattern formation

Abstract

A polyimide precursor having repeating units of the formula: wherein R 1 is a tetravalent organic group having 4 or more carbon atoms; R 2 is a trivalent or tetravalent organic group having one or more aromatic rings; R 3 is a monovalent organic group; A is a monovalent group showing acidity; and n is an integer of 1 or 2, is effective for preparing a highly sensitive negative-working photosensitive material developable with an alkaline aqueous solution in a short time with high resolution.

What is claimed is:  
     
         1 . A polyimide precursor having repeating units of the following formula (1) and a weight-average molecular weight of 10,000 to 200,000:  
       
         
           
           
               
               
           
         
       
       wherein R 1  is a tetravalent organic group having 4 or more carbon atoms; R 2  is a trivalent or tetravalent organic group containing one or more aromatic rings; R 3  is a monovalent organic group; A is a monovalent group showing acidity; and n is an integer of 1 or 2.  
     
     
         2 . A polyimide precursor according to  claim 1 , which further comprises repeating units of the formula:  
       
         
           
           
               
               
           
         
       
       wherein R 1  is a tetravalent organic group having 4 or more carbon atoms; R 3  is a monovalent organic group; R 4  is a divalent organic group containing one or more aromatic rings or silicon atoms; A is a monovalent group showing acidity; and n is an integer of 1 or 2, the number of repeating units of the formula (1) being 10 or more and the number of repeating units of the formula (2) being 90 or less, when a total of the repeating units of the fomrulae (1) and (2) is 100.  
     
     
         3 . A polyimide precursor according to  claim 1  or  2 , wherein A is at least one group selected from the group consisting of a sulfonic acid group, a sulfinic acid, a carboxylic acid group, and a hydroxyl group.  
     
     
         4 . A polyimide precursor according to  claim 1  or  2 , wherein R 1  is one member selected from the following formulae:  
       
         
           
           
               
               
           
         
       
     
     
         5 . A polyimide precursor according to  claim 1  or  2 , wherein R 2  is one member selected from the following formulae:  
       
         
           
           
               
               
           
         
       
       and Z is one member selected from the following formulae: —O—, —S—, —CO—, —SO 2 —, —CH 2 —, —C(CF 3 ) 2 —,  
       
         
           
           
               
               
           
         
       
     
     
         6 . A polyimide precursor according to  claim 1  or  2 , wherein R 3  is represented by the-formula:  
       
         
           
           
               
               
           
         
       
       wherein R 5 , R 6  and R 7  are independently a hydrogen atom, an alkyl group, a phenyl group, a vinyl group, or a propenyl group; and R 8  is a divalent organic group.  
     
     
         7 . A polyimide precursor according to  claim 6 , wherein R 3  is represented by the formula:  
       
         
           
           
               
               
           
         
       
     
     
         8 . A polyimide precursor according to  claim 1  or  2 , wherein R 3  in one molecule is represented by the formula:  
       
         
           
           
               
               
           
         
       
       wherein R 5 , R 6  and R 7  are independently a hydrogen atom, an alkyl group, a phenyl group, a vinyl group, or a propenyl group; and R 8  is a divalent organic group, in an amount of 10 to 100% by mole, and the remainder is an alkyl group having 1 to 6 carbon atoms.  
     
     
         9 . A polyimide precursor according to  claim 1  or  2 , wherein R 4  is one member selected from the following formulae:  
       
         
           
           
               
               
           
         
       
     
     
         10 . A polyimide having repeating units of the formula:  
       
         
           
           
               
               
           
         
       
       wherein R 1  is a tetravalent organic group having 4 or more carbon atoms; R 2  is a trivalent or tetravalent organic group containing one or more aromatic rings; A is a monovalent group showing acidity; and n is an integer of 1 or 2, and having a weight-average molecular weight of 10,000 to 200,000.  
     
     
         11 . A polyimide according to  claim 10 , which further comprises repeating units of the formula:  
       
         
           
           
               
               
           
         
       
       wherein R 1  is a tetravalent organic group having 4 or more carbon atoms; and R 4  is a divalent organic group having one or more aromatic rings or silicon atoms, the number of repeating units of the formula (10) being 10 or more, and the number of repeating units of the formula (11) being 90 or less, when a total of the repeating units of the formulae (10) and (11) is 100.  
     
     
         12 . A polyimide according to  claim 11 , wherein R 4  is a group of the formula:  
       
         
           
           
               
               
           
         
       
       in an amount of 1 to 30% by mole in a molecule.  
     
     
         13 . A polyimide precursor composition comprising a polyimide precursor having repeating units of the formula:  
       
         
           
           
               
               
           
         
       
       wherein R 1  is a tetravalent organic group having 4 or more carbon atoms; R 2  is a trivalent or tetravalent organic group containing one or more aromatic rings; R 3  is a monovalent organic group; A is a monovalent group showing acidity; and n is an integer of 1 or 2.  
     
     
         14 . A polyimide precursor composition according to  claim 13 , wherein the polyimide precursor further has repeating units of the formula:  
       
         
           
           
               
               
           
         
       
       wherein R 1  is a tetravalent organic group having 4 or more carbon atoms; R 2  is a trivalent or tetravalent organic group having one or more aromatic rings; R 3  is a monovalent organic group; R 4  is a divalent organic group containing one or more aromatic rings or silicon atoms; A is a monovalent group showing acidity; and n is an integer of 1 or 2, the number of repeating units of the formula (1) being 10 or more, and the number of repeating units of the formula (2) being 90 or less, when a total of repeating units of the formulae (1) and (2) is 100.  
     
     
         15 . A polyimide precursor composition according to  claim 13  or  14 , wherein the polyimide precursor is contained in an amount of 70 to 99 parts by weight, and a siloxane-containing polyamide acid having repeating units represented by the formula (24):  
       
         
           
           
               
               
           
         
       
       wherein R 1  is a divalent organic group having 4 or more carbon atoms; R 11  is a divalent organic group having one or more siloxane skeletons; R 12  is a divalent organic group having one or more siloxane skeletons; and R 13  is a divalent organic groups having one or more aromatic rings, is also contained in an amount of 1 to 30 parts by weight.  
     
     
         16 . A polyimide precursor composition according to  claim 15 , wherein the siloxane-containing polyamide acid further has repeating units of the formula;  
       
         
           
           
               
               
           
         
       
       wherein R 1  is a tetravalent organic group having 4 or more carbon atoms; and R 13  is a divalent organic group containing two or more aromatic rings, the number of repeating units of the formula (24) being 1 or more, and the number of repeating units of the formula (25) being 99 or less, when a total of the repeating units of the formulae (24) and (25) is 100.  
     
     
         17 . A polyimide precursor composition according to  claim 14 , wherein R 11  is one member selected from the following formulae:  
       
         
           
           
               
               
           
         
       
       and R 12  is one member selected from the following formulae:  
       
         
           
           
               
               
           
         
       
       wherein n is an integer of 2 to 12.  
     
     
         18 . A polyimide precursor composition according to  claim 13  or  14 , wherein the polyimide precursor is contained in an amount of 100 parts by weight, together with 0.1 to 50 parts by weight of a photosensitizer, and 0.1 to 50 parts by weight of a photopolymerization auxiliarly a gent.  
     
     
         19 . A process for forming a resin pattern, which comprises 
 forming a film of a photosensitive polyimide precursor composition of  claim 18  on a substrate,    exposing the film to light through a mask having a predetermined pattern, and    developing the exposed film using an alkaline aqueous solution.    
     
     
         20 . A negative-working photosensitive material comprising a photosensitive polyimide precursor which is soluble in an alkaline aqueous solution, but becomes insoluble in the alkaline aqueous solution after exposed to light.