Contrast-enhancing agent for photolithography

Claim 1

A contranst-enhancing agent for a photoresist layer which comprises, in admixture: (a) a photo-bleachable compound represented by the general formula ##STR17## in which A is an aromatic group selected from the class consisting of an unsubstituted or substituted phenyl group of the general formula ##STR18## unsubstituted or substituted α- or β-napthyl group of the general formula ##STR19## 9-anthranyl group, unsubstituted or substituted furyl group of the general formula ##STR20## unsubstituted or substituted benzofuryl group of the general formula ##STR21## and unsubstituted or substituted thienyl group of the general formula ##STR22## the subscript n is 1, 2 or 3, Z is a residue selected from the class consisting of pyridyl, quinolyl and benzothiazolyl groups forming a nitrogen-containing aromatic heterocyclic ring together with the nitrogen atom, X is an anionic group of monovalency and R 1 is a hydrogen atom or a group selected from the class consisting of alkyl, alkenyl and aralkyl groups, R 2 being an atom of hydrogen or a halogen or a group selected from the class consisting of alkyl, hydroxy, alkoxy, formyl and acyl groups; and (b) a water-soluble polymer selected from the class consisting of poly(vinyl alcohol), poly(vinyl pyrrolidone) and pullulan.

Claim 7

A method for enhancing the contrast of an image of a photoresist layer on a substrate surface which comprises, prior to exposure of the photoresist layer to light, the step of coating the surface of the photoresist layer with a contrast-enhancing agent comprising, in admixture, (a) a photo-bleachable compound represented by the general formula ##STR24## in which A is an aromatic group selected from the class consisting of an unsubstituted or substituted phenyl group of the general formula ##STR25## unsubstituted or substituted α- or β-naphthyl group of the general formula substituted α- or β-naphthyl group of the general formula ##STR26## 9-anthranyl group, unsubstituted or substituted furyl group of the general formula ##STR27## unsubstituted or substituted benzofuryl group of the general formula ##STR28## and unsubstituted or substituted thienyl group of the general formula ##STR29## the subscript n is 1, 2 or 3, Z is a residue selected from the class consisting of pyridyl, quinolyl and benzothiazolyl groups forming a nitrogen-containing aromatic heterocyclic ring together with the nitrogen atom, X is an anionic group of monovalency and R 1 is a hydrogen atom or a group selected from the class consisting of alkyl, alkenyl and aralkyl groups, R 2 being an atom of hydrogen or a halogen or a group selected from the class consisting of alkyl, hydroxy, alkoxy, formyl and acyl groups; and (b) a water-soluble polymer selected from the class consisting of poly(vinyl alcohol), poly(vinyl pyrrolidone) and pullulan, to form a contrast-enhancing layer thereon.

Claim 8

A method for enhancing the contrast of an image of a photoresist layer on a substrate surface which comprises, prior to exposure of the photoresist layer to light, the step of coating the surface of the photoresist layer with a contrast-enhancing agent comprising, in admixture, (a) a photo-bleachable compound represented by the general formula ##STR24## in which A is an aromatic group selected from the class consisting of an unsubstituted or substituted phenyl group of the general formula ##STR25## unsubstituted or substituted α- or β-naphthyl group of the general formula substituted α- or β-naphthyl group of the general formula ##STR26## 9-anthranyl group, unsubstituted or substituted furyl group of the general formula ##STR27## unsubstituted or substituted benzofuryl group of the general formula ##STR28## and unsubstituted or substituted thienyl group of the general formula ##STR29## the subscript n is 1, 2 or 3, Z is a residue selected from the class consisting of pyridyl, quinolyl and benzothiazolyl groups forming a nitrogen-containing aromatic heterocyclic ring together with the nitrogen atom, X is an anionic group of monovalency and R 1 is a hydrogen atom or a group selected from the class consisting of alkyl, alkenyl and aralkyl groups, R 2 being an atom of hydrogen or a halogen or a group selected from the class consisting of alkyl, hydroxy, alkoxy, formyl and acyl groups; and (b) a water-soluble polymer selected from the class consisting of poly(vinyl alcohol), poly(vinyl pyrrolidone) and pullulan, to form a contrast-enhancing layer thereon.