Gas Purification is critical to reducing the corrosion of gas delivery system components, maintaining system integrity, and improving process yield consistency. 

In a semiconductor process, fluorine and chlorine-based acid gases used in Etch, Epi, and Chamber Cleaning processes exhibit a high affinity for contamination when moisture is present. Corrosion typically occurs when stainless steel surfaces are constantly wetted by mild corrosive gases resulting in metal impurities or the buildup of particulate on the components within the gas delivery systems. The presence of moisture impurities can cause corrosion and result in the creation of volatile metals. 

Without purification, the H2O will continue to catalyze and contaminate the gas delivery system. 

Process Gas Purifiers are used to remove moisture or other impurities before the high-pressure regulator to protect the entire system. Purge Gas Purifiers are used to remove moisture or other impurities in the purge gas which contacts the process gas.  

Purging is an important part of a good calibration procedure and should always be practiced when handling corrosive gases. Purging ensures you have control over which gases are in your gas delivery system and thus are being exposed to internal components, sensors, or other equipment. It also helps to prevent unwanted reactions from taking place, which can greatly increase the service life of related components. What are the main reasons for purging? 

• Removing resident gases from a system before introduction of a new gas or gas mixture which may react. 

• Removing impurities from a system delivering a pure gas or sensitive gas mixture. 

• Removing dangerous or damaging gas from a system after use. 

CSI recommends automated purge with a purge gas purifier for pure corrosive gases to prolong the lifetime of the equipment. Luckily, they can be integrated into our Gas Cabinets!