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:
Mar. 12, 1996
Filed:
Dec. 30, 1994
Roger L Verkuil, Wappingers Falls, NY (US);
Min-Su Fung, LaGrangeville, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
A method and apparatus comprises heating a wafer to a temperature sufficient to temperature stress the wafer and enable ion motion. The wafer is then initialized in a measurement region with a non-contact corona discharge of a first polarity until a first dielectric field is developed, wherein any mobile ions present in the dielectric layer or at an air/dielectric interface move to a substrate/dielectric interface. A non-contact pulsed corona discharge of a second polarity, opposite the first polarity, is then applied to the wafer until a second dielectric field is developed and an amount of corona discharge Q.sub.MEASURED necessary to change the dielectric field from the first dielectric field to the second dielectric field is measured, wherein any mobile ions present at the dielectric/substrate interface move to the air/dielectric interface. An ideal amount of corona discharge Q.sub.IDEAL, in the absence of any highly mobile ionic species, necessary to change the dielectric field voltage of a dielectric layer of known thickness from a third dielectric field to a fourth dielectric field is then established. Lastly, measured corona discharge Q.sub.MEASURED is compared to ideal corona discharge Q.sub.IDEAL, wherein a quantitative difference between Q.sub. MEASURED and Q.sub.IDEAL is indicative of the amount of mobile charge Q.sub.MOBILE, Q.sub.MOBILE being representative of the amount of mobile ionic species in the dielectric layer.