Positive photosensitive resin composition for low-temperature process and method for preparing photoresist film

A positive photosensitive resin composition, comprising:

• an (A) alkali-soluble phenolic resin, obtained from polycondensation of phenols and aldehydes;
• a (B) compound with quinonediazide group;
• a (C) mixed solvent, comprising a (C-1) first solvent and a (C-2) second solvent, wherein the (C-1) first solvent has a volatilization rate of greater than 50 relative to a volatilization rate of butyl acetate, wherein the volatilization rate of the butyl acetate is defined as 100, and the (C-2) second solvent has a boiling point between 150° C. and 200° C.;
• and
• (D) at least one additive, having a molecular weight of 500-5000 and a structural unit as shown in Formula (I) as follow, wherein in Formula (I) R1 is selected from a group consisting of hydrogen, hydroxyl group, C1-C5 alkyl group, phenyl group, halogen atoms and cyano group, R2 is selected from a group consisting of hydrogen, acid radical, benzene and derivatives thereof, phenols, benzoic acid and derivatives thereof and aromatic heterocycles, and n is 10-80,
• wherein the (A) alkali-soluble phenolic resin accounts for 100 parts by weight, the (C) mixed solvent accounts for 400-1500 parts by weight, the (B) compound with quinonediazide group accounts for 20-40 parts by weight, the (D) at least one additive accounts for 20-40 parts by weight, and a weight ratio of the (C-1) first solvent to the (C-2) second solvent is between 90:10 to 50:50;
• wherein the (C-1) first solvent is selected from a group consisting of butyl acetate (NBAc), propylene glycol monomethyl ether (PGME), n-propyl propionate (NPP), isobutyl alcohol (IBA), isopropyl alcohol (IPA), isobutyl acetate (IBAC) and methyl isobutyl ketone (MIBK), and the (C-2) second solvent is selected from a group consisting of ethyl 3-ethoxypropionate, propylene glycol n-butyl ether (PnB), diethylene glycol methyl ether (DM), cyclohexanone (ANONE), propylene glycol diacetate (PGDA), dimethyl formamide (DMF), butyl methoxyacetate (MBA) and ethyl lactate (EL);
• and
• wherein the positive photosensitive resin composition is adapted to make a photoresist film through steps comprising:
• a coating step of coating the positive photosensitive resin composition onto a substrate;
• a pre-bake step at a temperature not greater than 90° C.;
• an exposure step;
• a development step;
• and
• a post-bake step at a temperature not greater than 90° C.;
• wherein the photoresist film made from the positive photosensitive resin composition has a pattern conforming to a half-cylinder, and a remaining film thickness value of greater than 90%.