Dissolution inhibitors and modulators for chemical amplification resists.

Abstract

Aliphatic esters, like malonates, β-ketoesters and acetone dicarboxylic acid esters as well as meldrums acid derivatives, which decompose upon acid catalysis to volatile compounds were evaluated as dissolution inhibitors and modulators for chemical amplification resist systems. The retention of these compounds in resist films under prebake conditions, their interaction with the resin as well as the acid catalyzed decomposition mechanism was investigated. Our studied have shown that these compounds function well as dissolution inhibitors in novolac matrices, but their ability to inhibit the dissolution of poly-vinylphenol is not very effective and therefore the process window is very narrow. However, select esters can be used as dissolution modulators in combination with special resins, for instance poly-vinylphenol protected partially with tetrahydropyranyl groups, where the resin performs the function of inhibition. The dissolution modulators just act in order to increases the discrimination between ex osed and unexposed parts, since they remains nearly uneffected in unexposed areas, but contribute to enhanced alkaline solubility of exposed areas, due to the formation of carboxylic acids upon photoinduced acid catalyzed decomposition. Such chemical amplified deep UV resist systems exhibit high sensitivity (20-40mJ/cm2) and resolution (0.5μm L/S).