The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 09, 1995
Filed:
Sep. 30, 1994
Sun-Chieh Chien, Hsin-Chu, TW;
Ming-Hua Liu, Hsin-Chu, TW;
United Microelectronics Corporation, Hsihchu, TW;
Abstract
An improved process for fabricating a planar field oxide structure on a silicon substrate was achieved. The process involves forming the field oxide by using the LOCal Oxidation of Silicon (LOCOS) process in which the device area is protected from oxidation by a silicon nitride layer. A sacrificial implant layer, such as CVD oxide, oxynitride or an anti-reflective coating (ARC) layer is used to fill in the gap between the silicon nitride and the field oxide structure and make more planar the substrate surface. The substrate surface is then implanted with As.sup.75 or p.sup.31 ions penetrating the sacrificial implant layer and forming a implant damaged layer on the field oxide. The implant damaged layer which etches faster in a wet etch in removed selectively thereby making a more planar field oxide structure. The method does not require a recess to be etched in the silicon substrate and therefore, has certain reliability and cost advantages. The invention also describes a method for forming more gradually sloping steps on the field oxide structure without using a sacrificial layer and a method for planarizing a CVD over a patterned conducting layer using photoresist or spin-on-glass as the sacrificial implant layer.