Developer for photosensitive polyimide resin composition

A developer for photosensitive polyimide resin compositions, which is suitable for use in development after patterning exposure of a photosensitive layer formed from a photosensitive polyimide resin composition containing a polyamic acid having at least one photopolymerizable functional group in its molecular chain, the developer comprising an alkaline aqueous solution containing a basic compound (A) represented by formula (1):

• wherein X+ is N+ or P+, R is an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 10 ring forming carbon atoms, Y− is a monovalent anion, m is 0 or 1, n is 3 or 4 and m+n is 4, with the proviso. that when m is 0, n is 4, and R is an alkyl group, the total number of carbon atoms of the 4 alkyl groups is at least 13, or when m is, 1, n is 3, and R is an alkyl group, the total number of carbon atoms of the 3 alkyl groups is at least 6, and wherein the basic compound (A) is a benzyltrialkylammonium salt, a benzyltriarylammonium salt, a tetraalkylphosphonium salt, a benzyltrialkylphosphonium salt or a benzyltriarylphosphonium salt, and at least one basic compound (B) selected from the group consisting of tetraalkylammonium salts in which the 4 alkyl groups have not greater than 12 total carbon atoms, choline, tertiary aliphatic amines in which the number of carbon atoms of each aliphatic group is from 1 to 5, pyridine and derivatives thereof, the basic compounds being in a molar ratio (A:B) ranging from 5:95 to 90:10, and the alkaline aqueous solution having a pH of at least 10.0.