Patent ID: 7449280

Claim:
A photoimageable composition suitable for use as a negative photoresist comprising: (A) at least one epoxidized polyfunctional bisphenol A formaldehyde novolak resin; (B) at least one polycaprolactone polyol reactive diluent, wherein the amount of component (A) is from about 95% to about 75% by weight of the sum of (A) and (B) and the amount of component (B) is from about 5% to about 25% by weight of the sum of (A) and (B); (C) at least one photoacid generator in an amount from about 2.5 to about 12.5 parts per hundred parts of resin and reactive diluent, which initiates polymerization upon exposure to actinic radiation; and (D) a sufficient amount of solvent to dissolve (A), (B) and (C); wherein the solvent is selected from the group consisting of 2-pentanone and a mixture of 2-pentanone and 1,3-dioxolane in a weight ratio of from 1:3 to 3:1.