13. Air-Condition and Refrigeration

Airborne molecular contaminations (AMCs), particles, and moisture, can significantly reduce the product yield in a semiconductor manufacturing. The cleanliness of front opening unified pods (FOUPs) is a critical concern for the industry. An innovative laminar air curtain was developed at Taipei Tech which helps to reduce and prevent moisture infiltration into the FOUP. The relative humidity (RH) inside the FOUP was significantly decreased using this technique. This technique has been adopted in many semiconductor industries in Taiwan. In this study, a smoke flow visualization was performed to justify the low RH values observed in the previous study. The FOUP and mini- environment used in the experiment were designed similar to real applications and were set up in a laboratory located at the National Taiwan University High-Tech Facility Research Center. At the present study, the Mie scattering technique was performed to evaluate the performance of the air curtain. An innovative laser sheet imaging system was used to produce a high-density light sheet which can cover the whole section of the FOUP and mini-environment. A scientific digital camera (Hamamatsu C13440) was used to record the smoke flow patterns. An innovative MATLAB program was developed to create short exposure particle image velocimetry. The exposure time was set to 6 milliseconds. The relative humidity values were measured inside the FOUP. Different moisture removal techniques such as air curtain, conventional and diffuser purge were performed. The results show that the moisture removal performance is significantly improved when the methods of air curtain and diffuser purge was performed at the same time.