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:
Apr. 04, 2000
Filed:
Dec. 08, 1997
Maria Chow Chan, San Jose, CA (US);
Advanced Micro Devices, Inc., Sunnyvale, CA (US);
Abstract
A method of preventing poly stringers in the formation of a memory device includes the steps of forming at least one field oxide region in a substrate and forming a tunnel oxide over the substrate. A first polysilicon layer is then formed over the tunnel oxide and a poly mask having a mask profile is formed over the first polysilicon layer. The first polysilicon layer is then etched in portions exposed by the poly mask, thereby creating a first polysilicon layer etch profile, wherein the first polysilicon layer etch profile is substantially ideally anisotropic and independent of the mask profile. An insulating layer and a conductive layer is then formed over the etched first polysilicon layer and portions of the conductive layer are then etched to form word lines. The insulating layer is then etched in regions adjacent the word lines, thereby leaving a substantially vertical insulative fence along the first polysilicon layer etch profile. Lastly, the first polysilicon layer is again etched in regions adjacent the word lines, wherein the etching of the first polysilicon layer is substantially anisotropic and removes substantially all the polysilicon in the regions adjacent the word lines, resulting in the prevention of poly stringers.