A composite PMMA resist is described with a linear sensitivity of 10−10C/cm for a 0.8‐&mgr;m resist thickness. It uses a simple one‐step development process, gives a pronounced undercut profile suitable for metal lift‐off, and to date has allowed interline spacings of 1.5 &mgr;m in 0.4‐&mgr;m‐thick resist. Some development and exposure characteristics are described.