A BIRD-BEAK-FREE SEALED-INTERFACE LOCAL OXIDATION TECHNOLOGY FOR SUBMICRON ULTRA-LARGE-SCALE INTEGRATED-CIRCUITS

For submicron ultra large scale integrated circuits (ULSI), an isolation technology known as sealed-interface local oxidation has been investigated. Plasma-enhanced chemical vapor deposition processes have been employed for the formation of composite structure of Si3N4/SiO2/Si3N4. This masking structure is highly effective for sealing the oxidants vertically as well as through the edge of sandwich mask during selective oxidation of silicon. Fully recessed and semirecessed field oxides are grown in order to form completely planarized topography during chip fabrication. The paper reports a bird's-beak-free LOCOS process for ULSIs. © 1990, The Electrochemical Society, Inc. All rights reserved.