Evaluation of Particle Shedding and Trace Metal Extraction from Centrifugal Pumps
Mark R. Litchy, Gary Van Schooneveld – CT Associates, Inc.
Juergen Hahn – Levitronix GmbH
The production of semiconductor devices continues to be extremely sensitive to particulate and metallic contamination. As feature sizes continue to decrease, the need for purity continues to increase. Various types of pumps have been used in bulk chemical delivery systems, recirculating etch baths, and other high purity process applications. Previous papers have shown that many of these pumps shed significant quantities of particles that may reduce product yield or impact the performance or lifetime of filters used in the process loop. Furthermore, metallic contamination in process chemicals can cause a variety of yield related issues.
In this experiment, high flow, high purity centrifugal pumps from three different manufacturers were evaluated for particle shedding in ultra pure water and trace metal extraction in hydrochloric acid. The pumps were evaluated for particle shedding over a range of operating conditions (flow rates and pressures) common to the pumps. In addition, the pumps were evaluated for trace metal extraction using a dynamic extraction method in 35% hydrochloric acid. Both surface and bulk contamination were determined with this method. The type and rate of trace metal extraction was also determined for each pump. Comparisons of pump cleanliness will be presented.
CTA publication #115: 2013 Ultra Pure Fluid and Wafer Cleaning Conference - Zurich Switzerland