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:
Dec. 17, 1996
Filed:
May. 13, 1993
Masato Toshima, Sunnyvale, CA (US);
Hiroji Hanawa, Santa Clara, CA (US);
Jerry Wong, Fremont, CA (US);
Gamma Precision Technology, Inc., Santa Clara, CA (US);
Abstract
An apparatus is disclosed for determining the concentration of a fluid. In one aspect of the invention an apparatus for detecting the ionic concentration of a fluid is provided. The ionic concentration detecting apparatus may include a resonance coil or other suitable receiver that arranged to be influence by the fluid being monitored. The resonance coil is driven by a high frequency signal having a frequency in the range of 10-100 MHz. A detector is provided to measure the losses experienced by the resonance coil. In another aspect of the invention, an ultrasonic based density detecting apparatus for detecting the density of the fluid is provided. The ionic concentration detecting device may be used in conjunction with the density determining device to provide concentration detecting capabilities for solutions having multiple constituents. One particularly beneficial application of the invention is for determining the concentration of an acidic solution used in a wafer wet cleaning step of a semiconductor fabrication process.