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. 12, 1998
Filed:
Jun. 13, 1995
Wataru Okase, Kanagawa-Ken, JP;
Tokyo Electron Limited, Tokyo-to, JP;
Tokyo Electron Tohoku Ltd, Iwate-ken, JP;
Abstract
A vertical heat treatment apparatus that includes a reaction tube for wafers to be loaded into from below and a heating unit surrounding the reaction vessel, or a single wafer heat treatment apparatus having a holder which provides a mount for wafers being loaded one by one into a reaction tube for heat treatment. The reaction tube has a structure of, e.g., two layers with a first layer of synthetic quartz glass made from a silicon compound, such as silicon tetrachloride, as a raw material. The first layer represents a surface that comes in contact with a heat treatment atmosphere. The second layer is of molten quartz glass made from quartz as a raw material and is external to the first layer. Synthetic quartz glass contains such traces of metals that scattered amounts of metals released into a heat treatment atmosphere due to exposure of the reaction tube to high temperatures is substantially zero. Furthermore, synthetic quartz glass and molten quartz glass are laid on each other, which improves heat resistance of the reaction tube. Thus, in conducting oxidation, diffusion, and other heat treatments on objects to be treated, e.g., semiconductor wafers, contamination of the objects with impurities can be minimized.