Image reversal process for normally positive photoresists

摘要

The invention relates to a method for image reversal of normally positive-working photoresist materials, in which a compound such as an onium salt is used in the layer, which splits off acid upon exposure, which, upon subsequent heating of an existing hydrophobic polymer such as imide hydroxyl or carboxyl substituent groups such as Butyloxycarbbonyl- or Benzyloxycarbomyl groups split off, whereby the polymer becomes soluble in aqueous alkaline solution, comprising the steps of: a. imagewise exposing the photoresist layer located on a substrate, the acid upon exposure contains a mixture of a nucleating compound and a polymer having acid-cleavable groups, b. the treatment of the photoresist layer with a gaseous base to neutralize the acid generated to form a salt, c. removing the excess base d. the whole-surface exposure of the photoresist layer for the photochemical generation of acid in the imagewise unexposed areas, e. heating the exposed photoresist layer by cleaving the cleavable groups of the polymer in the imagewise unexposed areas, and f. the development in an aqueous alkaline solution of the imagewise unexposed areas for removal.; In this way, images can be obtained which have the relative advantages of positive resist, such as resolution or better sources of geingeres structures.