"Investigating the Corrosion Resistance of Heat-Affected Zones in CrP Tubing," Micro, May 1996.
Abstract: Specialty gas delivery poses several challenges in semiconductor processing. Many of the challenges are associated with material compatibility of the gas delivery systems and process equipment with specialty gases. Typical areas of concern in specialty gas delivery include impurity levels, corrosion, component reliability, particle generation, and system or equipment lifetime. Research has shown that electropolished (EP) stainless steel tubes are susceptible to aggressive corrosion by halogen gases at specific sites, particularly near the welded areas of gas delivery systems supplying HCl. This study has demonstrated the corrosion resistance of CrP tubing for halogen gas delivery, with specific note of the superior corrosion resistance of CrP in the HAZ adjacent to the weld bead. CrP tubing is impervious to corrosion attack in the HAZ, while semiconductor-grade stainless steel experiences aggressive corrosion in this region, resulting in metallic particulate formation. Since electropolished stainless steel undergoes aggressive corrosive attack in the HAZ, CrP weldments are clearly preferable for applications requiring stringent control of metallic impurities and particles in halogen gas delivery. This concept can also be applied to other equipment that uses welded areas and is susceptible to corrosion by halogen gases. |
