Poly(Methyl Methacrylate-isobutylene) Copolymers as Highly Sensitive Electron Beam Resists

Methyl methacrylate-isobutylene P(MMA-IB) copolymers have been synthesized and investigated as positive electron beam results. A 75/25 composition P(MMA-IB) copolymer had a sensitivity of 4.5 x 10-6 C/cm2 at an accelerating voltage of 15 kV. The high sensitivity is attributed to the isobutylene “weak links” in the polymer chain. The incorporation of elastomeric isobutylene groups in the copolymers was also found to improve their adhesion on siloxane substrates. The improvement of the resist performance of PMMA represents an application of polymer tailoring wherein certain deficiencies in one polymer system (PMMA) may be overcome by copolymerization with another monomer (IB) which has good radiation sensitivity, but has limited resist applicability. © 1976, The Electrochemical Society, Inc. All rights reserved.