Resolution of polymethyl methacrylate: Molecular weights of 950 000 vs 50 000

The work examines the resolution and line-to-line resolution of two molecular weights of polymethyl methacrylate (PMMA), developed in 25%–50% solutions of methylisobutyl ketone in isopropanol. Both PMMA’s exhibited similar minimum linewidths of 15–18 nm. Measured linespread functions showed primary Gaussian standard deviations of 11.7 and 28 nm for the 950 and 50 K molecular weight PMMAs, respectively. Developer strength produced ⩽1 nm difference in the width of the linespread function. Atomic force microscope images of latent grating patterns show the same line-to-line resolution for the two undeveloped resists. Developed gratings show the 950 K PMMA to have superior line-to-line resolution. The results are analyzed through integration of the measured linespread functions.