Ultra-High Purity Argon Recycling for Semiconductor Wafer Fabrication

Semiconductor wafer fabrication uses the same CZ process that is used for solar PV wafer fabrication except that the ingots that the wafers are cut from are typically greater in diameter, 12” verses 8”, and the purity requirements of the argon purge gas are two to three orders of magnitude higher i.e., impurities in the 10 to 1ppb level. While the integrity of the CZ crystal puller itself is high, the same cannot be said for the dust filter, vacuum lines and vacuum pump. Even a very small leak in this chain will allow air to be sucked into the recycle loop and contaminate the argon allowing impurities such as nitrogen to build up. Note the ArgonØ cannot remove nitrogen. To overcome this problem GR2L has developed the NitroØ, a sub ambient temperature adsorptive purification module to complement the ArgonØ and deliver 1-10ppb levels of purity. The NitroØ was specifically developed to remove nitrogen, and other air gases, from the argon process return gas from an ArgonØ, and the combination, for the first time, offers the semiconductor wafer fabrication market an economic recycle opportunity.

The ArgonØ will remove the combustive/oxidative impurities in the recovered purge exhaust gas from the process down to at least 1ppm. The NitroØ module will “polish” the resulting gas and remove any residual nitrogen to deliver 1-10ppb level pure gas back to the process. No other gases or refrigerants are required, and the combined system operates 24/7 with minimal user intervention.