Characterization of negative electron beam resists based upon generalized gel formation theory

Contrast and sensitivity of negative electron beam resist have been studied, using the gel formation theory generalized for an arbitrary number of active bonds m created and retained at a reacting site in one irradiation-reaction process. For m = 1, such as in chloromethylated polystyrene (CMS), and m = 2, such as in polyesters and poly (glycidyl methacrylate) (PGMA), the dependence of contrast and sensitivity on inhibitor activity, molecular weight of polymer or copolymer, and polydispersivity is shown theoretically. The results obtained show that (i) the highest contrast is obtained for the negative resist in which m = 1 and the value of the contrast is 2.7 in the ordinarily used molecular size, and (ii) the sensitivity of the resist in which m = 2 is higher than that in which m = 1, provided other parameters are the same.