Alkali development-type solder resist, cured product thereof, and printed wiring board prepared by using the same

A solder resist developable with a dilute aqueous alkali solution comprising:

• (A) a carboxyl group-containing photosensitive resin obtained by reacting (a) a compound having two or more cyclic ether groups or cyclic thioether groups in the molecule with (b) an unsaturated monocarboxylic acid;
• reacting the product with (c) a polybasic acid anhydride;
• reacting the resulting resin with (d) a compound having a cyclic ether group and an ethylenic unsaturated group in the molecule;
• and reacting the product additionally with (c) the polybasic acid anhydride;
• (B) an oxime ester photopolymerization initiator comprising an oxime ester group represented by the following General Formula (I):
• (wherein R1 represents a hydrogen atom, an alkyl group having 1 to 7 carbon atoms, or a phenyl group;
• and R2 represents an alkyl group having 1 to 7 carbon atoms or a phenyl group);
• (C) a compound having two or more ethylenic unsaturated groups in the molecule;
• (D) a thermosetting component;
• and
• (E) at least one sensitizer selected from the group consisting of thioxanthone sensitizer, coumarin sensitizer and alkylaminobenzophenone sensitizer,
• wherein the dry film obtained by applying the composition has an absorbance of 0.3 to 1.2 per 25 μm of the film thickness at a wavelength of 400 to 410 nm, and
• the unsaturated monocarboxylic acid (b) comprises (b-1) an acrylic or methacrylic acid and (b-2) a compound represented by the following General Foimula (II):
• where R3 represents a hydrogen atom or a methyl group, m is an integer of 3 to 7, and an average value of n is an integer of 1 to 4.