Evaluation of Particle Shedding and Trace Metal Extraction from High Purity Pumps
Mark R. Litchy, CT Associates, Inc.
Reto Schoeb, 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 will continue to increase. Various types of pumps have been used in bulk chemical delivery systems, recirculating etch baths (REBs), and other high purity process applications. 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 purity pumps from three different manufacturers were evaluated for particle shedding in ultra pure water and trace metal extraction in hydrochloric acid. Pumps from three different manufacturers were evaluated for particle shedding during operation at multiple test conditions. Three sizes of pumps from each manufacturer were tested. The pumps were tested at similar operating conditions (flow rates and pressures). A subset of 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. In addition, the type and rate of trace metal extraction was determined for each pump. Comparisons of pump cleanliness will be presented.
Semiconductor Fabtech, 38(3):89-94