Polyimide precursor, resin composition including, and polyimide formed from such precursor, and use of the polyimide

A semiconductor device comprising:

• a semiconductor chip having a circuit;
• a sacrificial protection layer disposed to cover at least a lateral side of the circuit;
• and
• an encapsulating layer disposed to cover at least a lateral side of the sacrificial protection layer,
• wherein the sacrificial protection layer is made from a polyimide which is a product from polycondensation and ring formation of a polyimide precursor, the polyimide precursor including:
• a repeating unit of formulae (I) and (II):
• where R1 and R3 are each a tetravalent group of a tetracarboxylic dianhydride residue, and R2 and R4 are respectively a divalent group of a residue of a first-type diamine and a divalent group of a residue of a second-type diamine,
• wherein the first-type diamine is represented by formula (III):
• where X1 is a divalent group containing at least one amide group, R5 and R6 are respectively non-hydrogen substituents, and n1 and n2 are respectively numbers of the non-hydrogen substituents and independently range from 0 to 4, R5 and R6 being independently selected from the group consisting of a halogen, a C1 to C3 alkyl group, and a C1 to C3 haloalkyl group, and
• wherein the second-type diamine is represented by formula (IV):
• where X2 is a divalent group and is not a single bond, R7 and R8 are respectively non-hydrogen substituents, and m1 and m2 are respectively numbers of the non-hydrogen substituents and independently range from 0 to 4, a sum of m1 and m2 being at least 1, R7 and R8 being independently selected from the group consisting of a hydroxyl group, a halogen, a C1 to C3 alkyl group, and a C1 to C3 haloalkyl group, R7 and R8 having at least one hydroxyl group,
• wherein the polyimide includes a repeating unit of formulae (X) and (Y):
• where R1 and R2 in formula (X) have the same definitions as those in formula (I), and R3 and R4 in formula (Y) have the same definitions as those in formula (II).