Fabrication of ECL gate arrays on quick turn-around line

Abstract

A quick turn-around line (QTL) technology, including a high-speed on-line data system, electron-beam direct writing, and dry process technologies are described in this paper. Electron-beam pattern data is converted by a VAX 11/780 and transmitted to the electron-beam exposure system (EBES) through a communication controller at the speeds of 1 Mbits/s. After various data manipulations, patterns are quickly written directly on wafers. The first metal layer using an Al-Si-Cu alloy is etched in a reactive ion beam etcher with carbon tetrachloride (CCl 4 ). In order to avoid the charge-up phenomenon of the electron beam, the surface of the silicon nitride (SiN) interlevel insulation layer is coated with a thin conductive layer of TiW. TiW/SiN layers are successively etched by the reactive ion etching (RIE) with CF 4 + O 2 (2%). The damage induced by electron-beam irradiation on the device is perfectly annealed out with a 450°C anneal. Bias-temperature tests have been performed on various logic circuits used in a main frame computer.