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:
Jul. 22, 1997
Filed:
Dec. 12, 1996
Min-Su Fung, Lagrangeville, NY (US);
Roger Leonard Verkuil, Wappinger Falls, NY (US);
Bob Hong Yun, Hopewell Junction, NY (US);
International Business Machines Corporation, Armonk, NY (US);
Abstract
An apparatus for measuring charge in an oxide layer overlying a silicon substrate containing very high density product chips characterized by thick oxides and high substrate doping levels in the field regions. A specially designed extremely thin conductive probe is pressed against the oxide layer whose charge is to be measured. A bias is applied to the probe for biasing the underlying silicon surface into accumulation or inversion. An intensity modulated light beam is focussed at the point of probe contact. The resulting amplitude modulated photovoltage is detected and applied to a computer to derive the value of the oxide charge therefrom.