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:
Oct. 05, 1999
Filed:
Jun. 08, 1998
Advanced Micro Devices, Inc., , US;
Abstract
The present method provides for the detection and assessment of the net charge in a PECVD oxide layer deposited on a surface of a semiconductor substrate. Electrical potential differences across PECVD oxide layers on as-produced semiconductor substrates are measured. Resultant PECVD oxide charge derivative values are plotted on an control chart and compared to calculated control parameters. All measurement techniques are non-contact and non-destructive, allowing them to be performed on as-processed semiconductor substrates at any time during or following a wafer fabrication process. In a first embodiment, a contact potential difference V.sub.CPD between a vibrating electrode and the semiconductor substrate is measured while the semiconductor substrate beneath the vibrating electrode is subjected to a constant beam of high intensity illumination. The resultant value of V.sub.CPD is equal to the electrical potential difference across the PECVD oxide layer V.sub.OX (plus a constant). In a second embodiment, the semiconductor substrate is not illuminated curing the measurement of V.sub.CPD. A conventional SPV apparatus is used to measure the surface barrier potential V.sub.SP of the semiconductor substrate. Subtracting the measured value of V.sub.SP from the measured value of V.sub.CPD yields the value of V.sub.OX (plus a constant).