A photosensitive phosphorylated phenol-formaldehyde resin comprising the following repeating unit, wherein R1, is C1-6 alkylene or C6-10 alicyclic ring; R2 is hydrogen or methyl; R3 is C2-6 straight-chain or branched alkylene and optionally substituted with heteroatoms or aryl groups; Y is a functional group having an ethylenically unsaturated bond; and x is 0 or 1.