“…[47][48][49][50][51] Nevertheless, the sensitivity of ZEP520A is significantly higher than that of PMMA owing to the high efficiency of main-chain scission. 53) Many studies using ZEP have been carried out in terms of roughness, [54][55][56] dissolution dynamics, 57,58) development temperature, [59][60][61] thermal reflow, 62) shrinkage, 63) positive-negative inversion, 64) contrast curve improvement, 65) polydispersity, 53) molecular weight distribution, 66) and radiation-induced reactions. [67][68][69][70] Figure 4 shows the dependence of molecular weight distribution during exposure to EB on the initial molecular weight distribution.…”