The semiconductor industry uses a variety of specialized chemicals to make wafers and chips.
And the chemicals must be used in the proper concentrations to prevent defects and increase production yields. To help in this task, the Swagelok Co., Cleveland (swagelok.com), teamed with Jetalon Solution Inc., Campbell, Calif. (jetalon.com), to develop the CR-288 concentration monitor. It provides real-time analysis of up to four streams of fluids on one digital-display unit. (It still takes four sensors to monitor four streams.)
The device uses an optical approach, together with known indexes of refraction and reflection for specific fluids, to determine concentrations and temperatures. It measures concentrations with ±0.1% accuracy and 0.01% repeatability. Temperatures are accurate to ±0.1°C with repeatability and resolution of 0.01°C. Response time for the device is 1.2 sec. The display requires 4 to 20 mA to determine temperature and concentration, and has two digital 5-V outputs.