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:
Sep. 17, 2002
Filed:
Jul. 17, 2000
Wenge Yang, Fremont, CA (US);
Lewis Shen, Cupertino, CA (US);
Other;
Abstract
A resist mask pattern having a reduced thickness is formed overlying on a silicon oxynitride film during formation of a memory gate. The resist mask pattern has a resist thickness (3000 to 4000 Angstroms) sufficient to withstand removal during etching of the silicon oxynitride film. The silicon oxynitride film, having a thickness of about 800 to 1500 Angstroms, is etched based on the resist mask pattern and then used as a mask pattern to etch the polysilicon gate layer underlying the silicon oxynitride layer, to expose a portion of an isolation region aligned relative to the resist mask pattern. The portion of the resist mask remaining after etching, in combination with the etched silicon oxynitride film, have a sufficient overall thickness to serve as a channel implant mask. Use of the resist mask pattern having the reduced thickness improves yield by minimizing the occurrence of misregistration, and enables reliable formation of spaces in the mask pattern having widths of less than 0.25 microns using conventional deep ultraviolet (DUV) photolithography techniques.