Past exam of the MPhil in micro- and nanotechnology enterprise course of the University of Cambridge / 2021 / Paper 1 / 4 / i / Solution

Reading the straight-line extrapolation in the printed photoresist contrast curve gives approximately $D_0=20\mathrm{mJ}\mathrm{c}{\mathrm{m}}^{-2}$ at unit remaining thickness and $D_c=100\mathrm{mJ}\mathrm{c}{\mathrm{m}}^{-2}$ at clearing. On the logarithmic dose axis,The critical image modulation follows by requiring one exposure time to give $D_{\max }\ge D_c$ in a bright region and $D_{\min }\le D_0$ in a dark region:For unit object modulation, this meansThe doses are graphical estimates, so extra significant figures would not represent greater measurement accuracy.