Fabrication of integrated microcircuit devices

Abstract

Abstract A PROCESS FOR MANUFACTURING MICROCIRCUIT DEVICES HAVING MULTI-LEVEL INTERCONNECTION WIRING FORMED AS METAL LAYERS SEPARATED BY LAYERS OF DIELECTRIC MATERIAL. TO AVOID THE DEVELOPMENT OF CRACKS IN OVERLYING LAYERS OF DIELECTRIC MATERIAL, TAPERED EDGES ARE FORMED ON THE UNDERLYING METAL LAYER. PRIOR TO PHOTOLITHOGRAPHIC ETCHING TO FORM THE WIRING, THE METAL LAYER IS COVERED WITH A RELATIVELY THIN LAYER OF PHOSPHOSILICATE GLASS, AS THE DIELECTRIC, AND PHOTORESIST IS APPLIED THERETO. AFTER THE PHOTORESIST IS DEVELOPED, THE EXPOSED GLASS IS REMOVED BY SUBJECTING IT TO AN HF ETCHANT SOLUTION. THEN THE EXPOSED SURFACES OF GLASS AND METAL ARE SUBJECTED TO A SOLUTION OF A METAL ETCHANT AND A GLASS ETCHANT. AS THE GLASS IS REMOVED BY ITS ETCHANT, THE PHOTORESIST IS UNDERCUT, THEREBY EXPOSING TO THE METAL ETCHANT PROGRESSIVELY MORE OF THE UPPER SURFACE OF THE METAL, WITH RESULTANT FORMATION OF SLOPED OR TAPERED EDGES ON THE METAL WIRING. THE RELATIVE ETCH RATES, AS BETWEEN THE METAL AND THE GLASS, IS USED TO DETERMINE THE ANGLE OF SLOPE.

Inventors

• 👤 Ralph S Keen Jr

Bibliographic Details