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:
May. 23, 1995
Filed:
Jun. 29, 1993
Abstract
A method for detecting transition metal contamination in or on equipment and fluids used or being evaluated for use in the manufacture, handling, or shipping of silicon wafers and electronic devices manufactured on silicon wafers. A contamination monitor wafer having an average minority carrier lifetime greater than about 250 microseconds is processed using one or more pieces of equipment or fluids. As part of, or subsequent to the processing step, the contamination monitor wafer is exposed to a temperature of at least 600.degree. C. and the minority carrier lifetime values of the contamination monitor wafer is thereafter determined. To insure that the recombination process is dot dominated by the effects of oxygen precipitates, the contamination monitor wafer should have an oxygen precipitate density of less than 10.sup.8 oxygen precipitates per cubic centimeter before and after being exposed to said temperature of at least 600.degree. C.