Research on pollution prevention and control in semiconductor process tool and mini-environment

Taiwan currently holds the leading position globally in the semiconductor manufacturing industry, with wafer fabrication outsourcing playing a significant role. The cleanliness of cleanrooms is paramount to maintain and strengthen this position. During the wafer manufacturing process, Airborne Molecular Contamination (AMC) can lead to defects in wafers, thereby reducing yield. Traditional ballroom-style cleanrooms are increasingly unable to meet the current requirements for cleanliness and reliability. Thus, controlling gas-phase molecular contaminants in mini-environments has become a critical research topic. Currently, most process equipment maintains positive pressure relative to the surrounding environment to preserve internal cleanliness and prevent gas intrusion from cleanroom contamination. However, when process equipment is connected to the Equipment Front End Module (EFEM), the design of the positive pressure in the process equipment may introduce process gases into the connecting channels of the EFEM. This can lead to gas contamination in the mini-environment due to diffusion and turbulence generated by the movement of mechanical arms, resulting in corrosion and contamination of the mini-environment walls and equipment surfaces. This study utilizes Computational Fluid Dynamics (CFD) simulations to analyze contamination during the connection between the Equipment Front End Module (EFEM) and process equipment. It investigates measures to prevent the diffusion of process gases (HF) from process equipment to the mini-environment and provides a reference for future prevention of special gas contamination in mini-environments for the first time. The results show that by optimizing the process parameters such as floor suction velocity, laminar air curtain (LAC) flow rate, and duct local exhaust velocity, the HF pollutant isolation efficiency could be improved by up to 24.69 %. The findings of this study could be beneficial to improve the front opening unified pod (FOUP) cleaning efficiency in semiconductor manufacturing and even different areas of vacuum technology.