| "Weld-Site Contribution to Moisture Dry-Down in Tubing Using APIMS," Proceedings of The Conference on Advanced Microcontamination Control and Ultrapure Manufacturing, CleanRooms 96 West Session, Santa Clara CA, October 1996.
Abstract: The growing needs of the semiconductor industry require research and understanding of the factors that contribute to microcontamination. Surface roughness, total area, and material bulk properties are contributing factors in the dry-down performance of a system when exposed to ppb or greater levels of moisture contamination. Weld-sites are much rougher than typical semiconductor tubing. In order to quantify the weld bead's contribution to moisture dry-down, an unwelded tube is challenged with moisture and then monitored with an atmospheric pressure ionization mass spectrometer (APIMS). This dry-down is compared to the same tube with 50 welds. For double vacuum melt tubing, it is calculated that one weld bead contributes an additional 2.7mg H2O for a 200 ppb H2O challenge. In addition, a single melt tube with 50 welds is compared to a double vacuum melt tube with 50 welds. The difference between these two structures is 173mg H2O. |
