In-processes, such as etching/Chemical Mechanical Polishing (CMP) require FOUP purge while the FOUP door is open to an Equipment Front End Module (EFEM) load-port. To overcome this challenge, a new FOUP /LPU purge system is proposed. The system includes two uniform purge diffusers plus top-down pure gas curtain created by a so called “flow field former” when FOUP is in door-off condition.

Optimize operation parameters of Air Curtain. It＇s to prevent cross contamination and surface oxidation with a quick control of RH in FOUP door-off condition through efficient and purge rate saving CDA system. In an operating fab, the relative humidity inside a FOUP with door off and without purge is high (~40% RH), with purge can only reduce 5%~10%. It can reduce the relative humidity inside a FOUP to about 0~5%.

Through the newly designed FOUP purge mechanism by air curtain. Moisture and AMC concentration will be maintained at low levels during the wafer transferring period for the loading/unloading process, especially when the FOUP door is open. The purging process is widely used in the FOUP/LPU system with high end process<28nm.