LSI Surface Leveling by RF Sputter Etching

Abstract

A new technology for leveling LSI surfaces was developed by stabilizing the sputter etch rate of organic resists. Projections on LSI surfaces were coated with an organic resist, and etched off together with the resist, leaving a smooth surface. It has been reported by Vossen et al. that the sputter etch rate of organic resists was irreproducible and varied when they were etched together with oxides, such as SiO2. However, in this work, the etch rate of those re-sists could be m~de very stable and was nearly equal to that of SiO2 and SigN4 when they were tched in highly purified argon atmosphere. An effective technology for leveling LSI surfaces has long been sought for LSI manufacture. To achieve a higher packing density and higher speed, it is necessary to reduce the size of the devices and interconnection metallization. However, there exist many steep projections called, "bird's heads, " that is,