Reduction of Acid Gas Pollution in The Chemical Supply Area of A Semiconductor Factory

• Main Authors: Chung, Shang-Jen, 鍾尚仁
• Other Authors: Tsai, Chuen-Jinn
• Format: Others
• Language: zh-TW
• Published: 2016
• Online Access: http://ndltd.ncl.edu.tw/handle/v575u3

碩士 === 國立交通大學 === 工學院永續環境科技學程 === 105 === The clean room standard was controlled by the number of particles; it is controlled by the concentration of Airborne Molecular Contaminations (AMCs) due to the advanced semiconductor wafer manufacturing process. Therefore, it is critical for the semiconductor fab constriction to control AMCs. When the supply system is not properly maintained, the AMCs of acids, alkalis, and organic compounds are likely to be produced. The parallel plate wet denuder (PPWD) and Ion Chromatography‎(IC) are used to analyze the AMCs in the chemical supply area of the semiconductor fab in this study. The improvement of standard operational procedures to reduce the AMCs is also discussed. There are two scenarios in this study. Scenario 1 is the improvement of HCI supply system maintenance pollution. Scenario 2 is the improvement of HF drum replacement work pollution. The sampling concentration before operating the improvement scenario 1 was 4,616 ppbv which is closed to the national standard TLV-STEL of 5ppm. It is also within the AMCs pollution standards of 0.1ppm. A mobile compartment local exhaust equipment was designed for the study; its concentration was 0.4ppbv after the maintenance. The concentration was reduced to 0.15 ppbv after operating for 15 minutes. Therefore, it is indicated that an appropriate use of mobile compartment local exhaust equipment can effectively capture HCl pollutants, and can promptly remove contaminants. The improvement scenario 2 is HF drum replacement work pollution. The sampling concentration before operating the improvement scenario 2 was 42ppbv. The concentration was reduced to 8 ppbv after operating for one hour. It takes two hours to reach the concentration at below 2 ppbv by changing the environment. There are three different variables in this study. Variable 1: Increasing the negative pressure exhaust (the wind velocity of 0.2 m/s) in the supply system internal cabinet; its sampling concentration was 29ppbv. The result shows that variable 1 has a slight effect on the removal of internal cabinet contaminants. Variable 2: Switching off the supply system HEPA air supply; its sampling concentration was 120ppbv. The result shows that variable 2 has no effect on the removal of internal cabinet contaminants. Nevertheless, it increases the probability of the environment pollution. Variable 3: Changing the position of chemical drum and hood openings from a vertical direction to a parallel direction; its sampling concentration was 1.9ppbv. The result shows that variable 3 can effectively remove contaminants and prevent from spreading to the environment.