Self‐Developing Characteristics of Si Containing Polymers and Their Application to X‐Ray Lithography

Abstract

The self‐development characteristics of Si containing polymers were investigated with the objective of applying these polymers to the surface‐imaging process in x‐ray lithography. Polymers containing Si atoms in their backbones or substitutents were studied in detail; UV and Fourier transform infared spectra were used to study their reaction to soft x‐rays. The polymers exhibited postive‐tone characteristics when exposed to x‐rays. Their self‐development sensitivity and oxygen reactive ion etching (‐RIE) resistance were measured to estimate the feasibility of their use in lithography. Polysilanes and polystyrene showed low self‐development sensitivity while polymethacrylates showed high sensitivity. All of these polymers have ‐RIE resistance high enough for application as surface‐imaging resists. The films remaining after self‐development were characterized by estimating their durability against solvents, their thermal desorption spectra, and their x‐ray photoelectron spectra. A polymethacrylate derivative was found to be the most promising of the polymers; it was applied to pattern replication using dry development. The results show that Si containing polymers are fundamentally feasible for the postive‐tone dry processes.