A polyimide precursor having repeating units of the formula, wherein R1 is a tetravalent organic group having 4 or more carbon atoms; R2 is a trivalent or tetravalent organic group having one or more aromatic rings; R3 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.
Photosensitive polyimide precursor and its use for pattern formation