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. 15, 2009
Filed:
Jun. 11, 2007
Richard W. Foote, Kennedale, TX (US);
Richard W. Foote, Kennedale, TX (US);
National Semiconductor Corporation, Santa Clara, CA (US);
Abstract
A system and method is disclosed for using a differential wet etch stop technique to provide a uniform oxide layer over a metal layer in a laser trimmed fuse. A layer of boron doped oxide with a slow etch rate is placed over the metal layer. A layer of phosphorus doped oxide with a fast etch rate is placed over the boron doped oxide. The time period required for a wet etch process to etch through the phosphorus doped oxide is calculated. The wet etch process is then applied to the phosphorus doped oxide for the calculated time period. The wet etch process slows significantly when it reaches the boron doped oxide. This method forms a uniform layer of boron doped oxide over the metal layer.
Data source: USPTO (United States Patent and Trademark Office) public patent records. Weekly synchronization. How IDiyas builds this profile