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:
Nov. 26, 1996
Filed:
Jun. 28, 1995
Andrew C Campbell, Austin, TX (US);
Motorola, Inc., Schaumburg, IL (US);
Abstract
Fluctuations may occur in the vapor flux of a chemical being delivered in an otherwise inert gas stream from various causes. For example, the decrease in vapor flux over time may occur due to unintended condensation, instability in the delivery system and for other reasons. It has been discovered that a vapor flux monitor may be used in any system involved in the delivery of a vapor flux of a particular chemical reagent. The apparatus has a small aperture or hole through which a gas sample is introduced under low pressure. The sample undergoes a sudden, rapid pressure drop causing condensation of the reagent vapor into droplets where a relative flux can be determined by a measuring device, such as an in situ particle monitor (ISPM). This information can then be used to adjust the flow rate of the reagent. The vapor flux monitor can be adjusted to remove and analyze specific chemical reagents, and samples may be taken at any suitable point from the system. Further, the vapor flux monitor has particular application for systems using high flow rates of reagents, e.g. low pressure chemical vapor deposition (LPCVD) reactors, and reagents with low volatility, particularly organo-metallic compounds such as metal .beta.-diketonates.