Properties of the novel de-protecting unit for next generation ArF resist polymer

Abstract

Viewpoint of lithographic performance, the chemically amplified resist (CAR) is still promising candidates for the 32 nm node device manufacturing or below. However, CAR has an issue of low exposure latitude (EL) in the above node. To overcome the issue, it is important to control the acid diffusion at de-protecting process of the lithography system. We focused on a monomer unit that is able to control the acid diffusion during the post exposure bake (PEB) process. A novel secondary ester type methacrylate monomer was designed and synthesized as the unit that generates acid trapping ability according to the de-protecting reaction. The de-protecting reaction proceeded at general condition, and the acid trapping ability was confirmed by the model reaction in the solution. The unit must be useful as the adjusting unit of the acid diffusion. We also investigated the copolymers having this adjusting unit and the typical tertiary ester de-protecting unit for ArF resist main polymer. We will discuss the feature of the polymer including the de-protecting unit and its applications for next generation ArF chemically amplified resist.