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. 27, 1990
Filed:
Jul. 01, 1988
Lydia L Hwang, Midland, MI (US);
James R McCormick, Midland, MI (US);
Hemlock Semiconductor Corporation, Hemlock, MI (US);
Abstract
A method for analyzing and quantifying the individual trace metals content of a semiconductor material in the low to sub-parts per billion (ppba) range. The method comprises (A) float-zone refining of a sample of the semiconductor material creating a melt zone containing essentially all the trace metals of the sample; (B) cooling the melt zone to form a solid zone concentrated in trace metals; (C) separating the solid zone concentrated in trace metals from the sample of the semiconductor material; (D) converting the solid zone concentrated in trace metals into a form suitable for trace metals analysis; (E) analyzing the solid zone with known trace metals analytical techniques; and (F) calculating total trace metals from these analytical results. This method can also be applied to the small tip which forms on the side of the solid zone.