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. 20, 2010
Filed:
Aug. 10, 2005
Milton Beachy, Kissimmee, FL (US);
Thomas Craig Esry, Orlando, FL (US);
Daniel Charles Kerr, Orlando, FL (US);
Thomas M. Oberdick, Windermere, FL (US);
Mario Pita, Harmony, FL (US);
Milton Beachy, Kissimmee, FL (US);
Thomas Craig Esry, Orlando, FL (US);
Daniel Charles Kerr, Orlando, FL (US);
Thomas M. Oberdick, Windermere, FL (US);
Mario Pita, Harmony, FL (US);
Agere Systems Inc., Allentown, PA (US);
Abstract
A method of preventing formation of stringers adjacent a side of a CMOS gate stack during the deposition of mask and poly layers for the formation of a base and emitter of a bi-polar device on a CMOS integrated circuit wafer. The stringers are formed by incomplete removal of a hard mask layer over an emitter poly layer over a nitride mask layer. The method includes overetching the hard mask layer with a first etchant having a higher selectivity for the emitter poly material than for the material of the hard mask, determining an end point for the overetching step by detection of nitride in the etchant and applying a poly etchant that is selective with respect to nitride to remove any residual emitter poly.