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:
Jun. 03, 2008
Filed:
Mar. 22, 2006
Palanikumaran Sakthivel, Odenton, MD (US);
Thomas J. Buckley, Frederick, MD (US);
Alan F. Becknell, Ellicott City, MD (US);
Palanikumaran Sakthivel, Odenton, MD (US);
Thomas J. Buckley, Frederick, MD (US);
Alan F. Becknell, Ellicott City, MD (US);
Axcelis Technologies, Inc., Beverly, MA (US);
Abstract
Processes for monitoring the levels of oxygen and/or nitrogen in a substantially oxygen and nitrogen-free plasma ashing process generally includes monitoring the plasma using optical emission. An effect produced by the low levels of oxygen and/or nitrogen species present on other species generally abundant in the plasma is monitored and correlated to amounts of oxygen and nitrogen present in the plasma. This so-called 'effect detection' process monitors perturbations in the spectra specifically associated with species other than nitrogen and/or oxygen due to the presence of trace amounts of oxygen and/or nitrogen species and is used to quantitatively determine the amount of oxygen and/or nitrogen at a sensitivity on the order of 1 part per million and potentially 1 part per billion.