Organic underlayer and methods of EUV dose reduction

Abstract

A method of forming a microelectronic structure on a substrate is disclosed. The method includes applying an underlayer forming composition to an uppermost intermediate layer of a lithography stack, if present, or to the substrate to form an underlayer. The underlayer forming composition includes a pre-ionic compound that generates an ionic compound, moiety, or both during post-application bake. The pre-ionic compound can include, for example, a copolymer having glycidyl methacrylate and 4-vinylpyridine. An EUV-sensitive photoresist comprising a metal-oxide is applied directly on an upper surface of the underlayer. EUV lithography is then performed. This method can be used to achieve dose reduction compared to prior art methods of EUV lithography using metal-oxide containing photoresists. Various underlayer forming compositions for performing EUV lithography using a metal-oxide-containing resist are also disclosed.