Photosensitive polyimide composition and photoresist film made thereof

A photosensitive polyimide composition comprising a polyimide resin having a structural unit represented by the formula (1) and a structural unit represented by the formula (2), an quinonediazide sulfonate, a thermal curing agent, and a thermal acid generator,

• wherein in the formulae (1) and (2), n is an integer of 10 to 600, Ar1 is a tetravalent organic group, Ar2 is a divalent to tetravalent organic group, Ar3 is a divalent aromatic group, and R1 is an OH group or a COOH group;
• the thermal curing agent comprises an epoxy compound and a melamine compound, and the weight ratio of the epoxy compound to the melamine compound is 3:1 to 4:3;
• wherein the photoresist film has properties of chemical resistance and insulation, and the property of chemical resistance is expressed by a residual film rate of greater than 90%;
• wherein the thermal acid generator is an onium sulfonium salt selected from at least one of the group consisting of chloride, bromide, p-toluenesulfonate, trifluoromethanesulfonate, tetrafluoroborate, tetrakis(pentafluorophenyl)borate, tetrakis(pentafluorophenyl)ruthenate, hexafluorophosphate, hexafluoroarsenate, and hexafluoroantimonate.