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

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 (O 2 -RSB) 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 O 2 -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.