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:
Aug. 10, 1999
Filed:
Nov. 25, 1997
Carl F Cherko, St. Charles, MO (US);
Harold Korb, Town & Country, MO (US);
Richard G Schrenker, Chesterfield, MO (US);
Dick S Williams, Houston, TX (US);
MEMC Electronic Materials, Inc., St. Peters, MO (US);
Abstract
An apparatus for pulling a monocrystalline ingot from a semiconductor source material located within a growth chamber as the ingot is grown on a seed crystal according to the Czochralski method. The apparatus comprises a drum, a chuck constructed for holding the seed crystal and the ingot, and a cable having a first end connected to the drum, a second end connected to the chuck and a portion wound around the drum. The portion of the cable wound around the drum exerts a normal force on a circumferential surface of the drum corresponding to the tension in the cable. The drum and cable interact to produce a friction force resisting sliding movement of the cable relative to the drum in a direction lengthwise of the cable. The drum is capable of unwinding cable from the drum thereby to let out the cable and lower the chuck, and capable of winding the cable around the drum thereby to reel in the cable and draw the chuck upwardly. The chuck has a mass selected to exert a pre-tension on the cable prior to growing the ingot such that the increase in the friction on the portion of the cable wound around the drum as the cable is reeled in to pull the ingot from the source material is at least equal to the increase of the weight of the ingot as it grows on the seed crystal from the molten source material.