Past exam of the MPhil in micro- and nanotechnology enterprise course of the University of Cambridge / 2021 / Paper 1 / 3 / i / Solution 2026-10-20
View more
The resist is positive tone, because the written regions are the regions removed during development. A suitable example is poly(methyl methacrylate), conventionally PMMA, used in its ordinary positive-tone electron-beam exposure regime. Electron-induced chain scission reduces its molar mass and increases its solubility in the developer.
The fact that this writing step fabricates an extreme ultraviolet mask does not make the resist an EUV-exposed resist: the exposure process being classified here is the electron-beam mask-writing step.
Read the full article