Spun‐On Contour Coating Characterizations for Advanced Optical Lithography

AbstractSpun‐on contour coating properties are characterized for two absorptive undercoats, AUCs, and a contrast‐enhanced layer, CEM‐388. A low‐pass frequency filter contour modeling procedure is used to simulate the coating contours on a real silicon‐on‐sapphire epi‐island layout. The computed thickness variations are used to estimate the variation in optical densities of these spun‐on films on the topography. The variations in optical densities arc discussed in terms of the expected dimensional deviations introduced into the patterned resist layer. At the same spun‐on thickness, one absorptive undercoat offers improvement in dimensional control when compared to the other. Changes in the thickness of the CEM‐388 layer may also introduce significant dimensional deviations in the underlying positive resist layer. In, both cases the more conformal spun‐on contour coating properties produce improved resist imaging.