Publication Date
Spring 1996
Degree Type
Master's Project
Degree Name
Master of Science in Engineering (MSE)
Department
General Engineering
First Advisor
Dr. Peter Reischl
Abstract
Particulate monitoring in a clean environment is crucial to semiconductor fabrication facilities. The determination of particle count and size is necessary to find and eliminate the source of contamination. A method of counting particles is a Condensation Nucleus Counter (CNC). The problem with a factory built CNC is that its control mechanism is not sufficient for accurate particle counting. As the differential temperature between the condenser and saturator changes, so does the counting efficiency. A newly developed control algorithm has been implemented and can hold the temperature to ±0.1 ° C versus the factory control which has only ±1.5° C capability. The controller is very robust and is not affected by external disturbances.
It was found that the CNC could change its particle size counting threshold by adjusting the differential temperature between the condenser and saturator. A low differential temperature would eliminate counting of certain size particles, where a high value would be more efficient.
Recommended Citation
Scheer, Craig Allen, "Improved Temperature Controlled Condensation Nucleus Counter for Particulate Monitoring in a Clean Environment" (1996). Master's Projects. 1714.
https://scholarworks.sjsu.edu/etd_projects/1714
