[en] Among the most advanced chips currently in production are those made with Hewlett-Packard's NMOS III technology in Fort Collins, Colorado. A chip set made with this process is the heart of the HP 9000 Computer. NMOS III is a modified n-channel silicon gate process featuring three and one-half levels of interconnect: diffusion, polysilicon with buried contacts and two levels of refractory metal. Minimum dimensions in the first metal layer consist of 1.5 micron lines and 1.0 micron spaces. Tungsten was chosen for the metal layers because of its conductivity and current carrying capability. The process for fabricating these layers is described. Particular emphasis has been placed on considerations given to plasma etching