According to the present invention, a resin composition can be provided, comprising at least three components (a), (b) and (c), wherein component (a) is a polymer having a structure represented by the following formula (1), component (b) comprises thermal crosslinking agent (b1) and thermal crosslinking agent (b2), and component (c) is a photosensitizer, wherein R.sup.1 and R.sup.2 are independently selected from groups containing at least one atom other than hydrogen; and R.sup.3 and R.sup.4 are independently selected from a hydrogen atom or an organic group having 1 to 20 carbon atoms, and n is an integer selected from 1 to 10. The use of the resin composition of the present invention can result in a better flatness and bending recovery performance.

According to the present invention, a resin composition can be provided, comprising at least three components (a), (b) and (c), wherein component (a) is a polymer having a structure represented by the following formula (1), component (b) comprises thermal crosslinking agent (b1) and thermal crosslinking agent (b2), and component (c) is a photosensitizer, wherein R.sup.1 and R.sup.2 are independently selected from groups containing at least one atom other than hydrogen; and R.sup.3 and R.sup.4 are independently selected from a hydrogen atom or an organic group having 1 to 20 carbon atoms, and n is an integer selected from 1 to 10. The use of the resin composition of the present invention can result in a better flatness and bending recovery performance.

Provided is a curable resin composition having developability and resolution improved without degrading the heat resistance and the chemical resistance, furthermore, a curable resin composition that is useful as a PID material for optical uses or a material for optical sensor protective films and enables the formation of a cured product having both higher transparency and excellent heat resistance, a dry film containing the curable resin composition, a cured product thereof and a printed wiring board including the cured product. A curable resin composition containing (A) an amide-imide resin, (B) a compound having an ethylenic double bond and (C) a photopolymerization initiator, wherein the amide-imide resin (A) is a reaction product of an isocyanurate-type polyisocyanate synthesized from an isocyanate having an aliphatic structure and a tricarboxylic acid anhydride and has a number-average molecular weight of 500 to 1000.

A negative-type photosensitive resin composition that has a satisfactory imidization rate and can yield a resin layer with high chemical resistance, even under low-temperature curing conditions of 200° C. or below, the negative-type photosensitive resin composition containing a photopolymerization initiator (B) in a proportion of 0.1 part by mass to 20 parts by mass with respect to 100 parts by mass of a polyimide precursor (A), the polyimide precursor (A) being a polyamic acid ester or polyamic acid salt with a specific structure, and the weight-average molecular weight (Mw) of the polyimide precursor (A) being 3,000 or greater and less than 16,000, in terms of polystyrene, according to gel permeation chromatography (GPC).

A negative-type photosensitive resin composition that has a satisfactory imidization rate and can yield a resin layer with high chemical resistance, even under low-temperature curing conditions of 200° C. or below, the negative-type photosensitive resin composition containing a photopolymerization initiator (B) in a proportion of 0.1 part by mass to 20 parts by mass with respect to 100 parts by mass of a polyimide precursor (A), the polyimide precursor (A) being a polyamic acid ester or polyamic acid salt with a specific structure, and the weight-average molecular weight (Mw) of the polyimide precursor (A) being 3,000 or greater and less than 16,000, in terms of polystyrene, according to gel permeation chromatography (GPC).

A photosensitive resin printing original plate for letterpress printing having a photosensitive resin layer formed of a photosensitive resin composition containing at least a polymer compound (A), a dibasic acid diester (B) represented by the following general formula (I), a photopolymerizable compound (C), and a photopolymerization initiator (D), in which the content of the dibasic acid diester (B) in the photosensitive resin composition is 2.5 to 15 mass %:

##STR00001## (where R.sup.1 represents a divalent aliphatic hydrocarbon group having 2 to 8 carbon atoms, a divalent aromatic hydrocarbon group having 6 to 14 carbon atoms, or a divalent aliphatic cyclic hydrocarbon group having 4 to 14 carbon atoms, and R.sup.2 and R.sup.3 may be the same as or different from each other and each represents a linear or branched aliphatic hydrocarbon group having 1 to 12 carbon atoms).

A photosensitive resin printing original plate for letterpress printing having a photosensitive resin layer formed of a photosensitive resin composition containing at least a polymer compound (A), a dibasic acid diester (B) represented by the following general formula (I), a photopolymerizable compound (C), and a photopolymerization initiator (D), in which the content of the dibasic acid diester (B) in the photosensitive resin composition is 2.5 to 15 mass %:

##STR00001## (where R.sup.1 represents a divalent aliphatic hydrocarbon group having 2 to 8 carbon atoms, a divalent aromatic hydrocarbon group having 6 to 14 carbon atoms, or a divalent aliphatic cyclic hydrocarbon group having 4 to 14 carbon atoms, and R.sup.2 and R.sup.3 may be the same as or different from each other and each represents a linear or branched aliphatic hydrocarbon group having 1 to 12 carbon atoms).

A photosensitive resin composition including a poly(imide-benzoxazine) block copolymer, and a cured film. The poly(imide-benzoxazine) block copolymer included in the photosensitive resin composition enables the formation of a cured film having excellent mechanical and insulation even at a low temperature of less than 200° C.

A photosensitive resin composition including a poly(imide-benzoxazine) block copolymer, and a cured film. The poly(imide-benzoxazine) block copolymer included in the photosensitive resin composition enables the formation of a cured film having excellent mechanical and insulation even at a low temperature of less than 200° C.

A method of manufacturing a semiconductor device includes forming a polymer mixture over a substrate, curing the polymer mixture to form a polymer material, and patterning the polymer material. The polymer mixture includes a polymer precursor, a photosensitizer, a cross-linker, and a solvent. The polymer precursor may be a polyamic acid ester. The cross-linker may be tetraethylene glycol dimethacrylate. The photosensitizer includes 4-phenyl-2-(piperazin-1-yl)thiazole. The mixture may further include an additive.