A positive working photosensitive composition comprising: a. at least one photoacid generator; b. at least one polymer, comprising one or more (meth)acrylate repeat units and further comprising one or more repeat units with at least one acid cleavable group, which is a polymer of the following formula: wherein R 8 - R 12 are, independently, -H, F or -CH 3, A is a linear or branched C 1 -C 10 alkylene group, B is a C 1 -C 12 alkyl or alicyclic group, D is a linking group that may be a chemical bond, a carboxylate group, wherein the carbonyl carbon is bonded to the polymer backbone, or a -COOCH 2 - group, wherein the carbonyl carbon is bonded to the polymer backbone, Ar is a unsubstituted aromatic group or heteroaromatic group, E is a linear or branched C 2 -C 10 alkylene group, G is an acid cleavable group, v is 0 - 10 mole%, w is 0 mole% - 20 mole%, x is 14 mole% - 80 mole%, y is 0 mole% - 40 mole% and z is 20 mole% - 50 mole%; c. at least one heterocyclic thiol compound comprising a ring structure chosen from the general formulas: or tautomers thereof, wherein the ring structure is a single ring structure having 4 - 8 atoms, or a multi ring structure having 5 - 20 atoms, and wherein the single ring structure or the multi ring structure comprises an aromatic, non aromatic, or heteroaromatic ring, and wherein X is coupled into the ring by a single bond and is chosen from CR 1 R 2, O, S, Se, Te, or NR 3, or X is coupled into the ring by a double bond and is chosen from CR 1, or N, and Y is chosen from CR 1 or N, and wherein R 1, R 2, and R 3 are independently selected from a group consisting of H, a substituted alkyl group having 1-8 carbon atoms, unsubstituted alkyl group having 1-8 carbon atoms, a substituted alkenyl group having 1-8 carbon atoms, unsubstituted alkenyl group having 1-8 carbon atoms, a substituted alkynyl group having 1-8 carbon atoms, unsubstituted alkynyl group having 1-8 carbon atoms, a substituted aromatic group having 1-20 carbon atoms, a substituted heteroaromatic group having 1-20 carbon atoms, unsubstituted aromatic group having 1-20 carbon atoms and unsubstituted heteroaromatic group having 1-20 carbon atoms, and further, wherein the ring structure of the heterocyclic thiol compound may be substituted with saturated or unsaturated hydrocarbon groups, substituted or unsubstituted aromatic rings, aliphatic, aromatic or heteroaromatic alcohols, amines, amides, imides carboxylic acids, esters, ethers and/or halides. a. at least one photoacid generator; b. at least one polymer, comprising one or more (meth)acrylate repeat units and further comprising one or more repeat units with at least one acid cleavable group, which is a polymer of the following formula: wherein R 8 - R 12 are, independently, -H, F or -CH 3, A is a linear or branched C 1 -C 10 alkylene group, B is a C 1 -C 12 alkyl or alicyclic group, D is a linking group that may be a chemical bond, a carboxylate group, wherein the carbonyl carbon is bonded to the polymer backbone, or a -COOCH 2 - group, wherein the carbonyl carbon is bonded to the polymer backbone, Ar is a unsubstituted aromatic group or heteroaromatic group, E is a linear or branched C 2 -C 10 alkylene group, G is an acid cleavable group, v is 0 - 10 mole%, w is 0 mole% - 20 mole%, x is 14 mole% - 80 mole%, y is 0 mole% - 40 mole% and z is 20 mole% - 50 mole%; c. at least one heterocyclic thiol compound comprising a ring structure chosen from the general formulas: or tautomers thereof, wherein the ring structure is a single ring structure having 4 - 8 atoms, or a multi ring structure having 5 - 20 atoms, and wherein the single ring structure or the multi ring structure comprises an aromatic, non aromatic, or heteroaromatic ring, and wherein X is coupled into the ring by a single bond and is chosen from CR 1 R 2, O, S, Se, Te, or NR 3, or X is coupled into the ring by a double bond and is chosen from CR 1, or N, and Y is chosen from CR 1 or N, and wherein R 1, R 2, and R 3 are independently selected from a group consisting of H, a substituted alkyl group having 1-8 carbon atoms, unsubstituted alkyl group having 1-8 carbon atoms, a substituted alkenyl group having 1-8 carbon atoms, unsubstituted alkenyl group having 1-8 carbon atoms, a substituted alkynyl group having 1-8 carbon atoms, unsubstituted alkynyl group having 1-8 carbon atoms, a substituted aromatic group having 1-20 carbon atoms, a substituted heteroaromatic group having 1-20 carbon atoms, unsubstituted aromatic group having 1-20 carbon atoms and unsubstituted heteroaromatic group having 1-20 carbon atoms, and further, wherein the ring structure of the heterocyclic thiol compound may be substituted with saturated or unsaturated hydrocarbon groups, substituted or unsubstituted aromatic rings, aliphatic, aromatic or heteroaromatic alcohols, amines, amides, imides carboxylic acids, esters, ethers and/or halides.