Variation with composition of the intrinsic sensitivity of halogen-substituted styrene copolymers to electron-beam radiation

Abstract

In the polymer literature (Handbook of Polymer Science and Technology, ed. N. P. Cheremisinoff, Marcel Dekker, New York, 1989, vol. 1, p. 307) a simple equation has been derived to estimate the lithographic sensitivity of a copolymer of known composition and molecular weight from the constituent homopolymer values. Sensitivity has often been equated with the reactivity parameter D_gM_w where D_g is the gel dose and M_w the weight-average molecular weight of the polymer. This report demonstrates that the use of the reciprocal reactivity (D_gM_w)^–1 leads to a clearer interpretation of the lithographic results and that furthermore, the conclusions drawn from earlier analyses neglect the consequences of co-operative action between differing monomer units within copolymers.