Water soluble photosensitive polymide polymer, its preparation and photoresist containing the same

A process for producing water soluble photosensitive polyimide polymer having repeating units represented by formula (I):

• R1 represents a tetra-valence organic group having 4 or more carbon atoms;
• R2 is a three- or tetra-valence organic group, which is optionally substituted with carboxyl group;
• R3 represents a two- to tetra-valence organic group;
• A represents OH or COOH group;
• R4 and R5 are the same or different, each represents an alkylene group having 1˜6 carbon atoms, an arylene group, arylalkylene group, arylene-oxy-alkylene group having 6˜20 carbon atoms;
• R7 and R8 are the same or different, each represents the group selected from a hydrogen, a halogen, a carboxyl, a linear or cyclic alkyl having 1˜20 carbon atoms, an aryl, alkylaryl, and arylalkyl having 6˜20 carbon atoms;
• R9 represents a hydrogen atom or an alkyl group having 1-6 carbon atoms;
• x represents an integer of 1 or 2;
• y represents an integer of 0, 1 or 2;
• a, b and n each represents an integer equal to or greater than 1;
• m and k each represents an integer equal to or greater than 0];
• wherein the above repeating units are in random or block arrangement;
• the process comprises the following steps:
• (a) reacting a tetra-carboxyl acid dianhydride with a diamine having carboxyl and/or hydroxyl functional groups to obtain a polyamic acid precursor having carboxyl and/or hydroxyl functional groups in the main chain;
• wherein the molar ratio of tetra-carboxyl acid dianhydride:
• diamine is 1:0.8˜1:1.2;
• (b) heating and subjecting the polyamic acid precursor having carboxyl and/or hydroxyl functional groups in the main chain obtained from step (a) to cyclization to obtain a polyimide having carboxyl and/or hydroxyl functional groups in the main chain;
• and
• (c) reacting the polyimide having carboxyl and/or hydroxyl functional groups in the main chain obtained from step (b) with a dianhydride of the following formula (II) to subject to open-ring reaction:
• R7 and R8 are the same or different, each represents the group selected from a hydrogen, a halogen, a carboxyl, a linear or cyclic alkyl having 1˜20 carbon atoms, an aryl, alkylaryl, and arylalkyl having 6˜20 carbon atoms;
• R9 represents a hydrogen atom or an alkyl group having 1-6 carbon atoms);
• to produce a polyimide polymer having repeating unit which has acrylic acid group in the main chain, as shown in the above general formula (I).