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. 23, 2004
Filed:
Aug. 13, 2001
Todd A. Cerni, Mead, CO (US);
Particle Measuring Systems, Inc., Boulder, CO (US);
Abstract
An apparatus and method for determining the chemical content of a chemical mechanical planarization (CMP) slurry. A CMP sample cell has windows for passing electromagnetic radiation. Three wavelengths of electromagnetic radiation, one of which is strongly absorbed by said CMP slurry and the other two of which are weakly absorbed by said CMP slurry, are directed through said sample cell to a detector, which processes a signal. A processor utilizes the signal to determine the transmission at each wavelength, then utilizes Beer's law to determine a transmission function for each wavelength, and calculates the wavelength dependent particle transmission for each wavelength using an optical model, to form a system of three equations in three unknowns, which are solved to determine a parameter representative of the chemical content of the CMP slurry.