Electricity: measuring and testing – Electrolyte properties – Using a conductivity determining device
Patent
1993-05-13
1996-12-17
Regan, Maura K.
Electricity: measuring and testing
Electrolyte properties
Using a conductivity determining device
324204, 324715, 204406, 422 8202, G01R 3300
Patent
active
055857299
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.
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Hanawa Hiroji
Toshima Masato
Wong Jerry
Gamma Precision Technology, Inc.
Regan Maura K.
Solis Jose M.
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