<title>Enhanced process control of submicron contact definition</title>

Abstract

The aggressive drive to reduce device geometries to submicron levels while utilizing ULSI design capabilities has posed many challenges to traditional semiconductor process technology. Among the most critical is the ability to maintain satisfactory contact between two levels of metal through contact holes significantly smaller than the actual design rule itself. Traditional technologies for greater than one micron design rules are not capable of maintaining the consistent output necessary to achieve and maintain Six Sigma process control. Isotropic plasma etching of doped and undoped oxides has been studied as an alternative to the wet isotropic etch in the traditional wet-dry contact hole etch process scheme. The isotropic etch was characterized using Taguchi and Response Surface Methodology (RSM) multilevel statistical experimental designs. Optimized conditions resulted in process capability of greater than 2. 0 Cpk control measured in reference to critical dimension performance and electrical data analysis.