Water-soluble photopolymer and method of forming pattern by use of the same

A pattern forming organic film of a multi-layer structure consisting essentially of:

• a radiation sensitive resin resist layer, and
• a water-soluble polymeric film as a separate layer containing pullulan produced and refined by bacterial culture as the main polymer, said polymeric film formed on said resist, and which polymeric film has color-fading or bleaching action against light for exposure onto said resist and which polymeric film can be removed by a developing agent for use in the development of said radiation sensitive resist.

A pattern forming organic film of a multi-layer structure consisting essentially of:

• a radiation sensitive resin capable of being developed by a developing agent, and
• a separate water-soluble polymeric layer containing pullulan as the main polymer, which pullulan is produced and refined by bacterial culture, and which water-soluble layer can be removed by a developing agent to be used for the development of said radiation sensitive resin, said water-soluble polymeric layer containing a light absorbing agent capable of absorbing light in the ultraviolet region of 500 nm or less, said light absorbing agent being a compound which contains at least one member selected from the group consisting of a diazo group, and azide group, a cinnamoyl group, an acryloyl group, a cinnamiliden group, a double bond, an epoxy group, a triple bond, a chloromethyl group, an iodomethyl group, a silicon-silicon double bond, a carbon-carbon single bond, and a carbon-sulfur single bond.