Airflow and Particle Characteristics of FOUP/LPU Minienvironment System for 300mm Wafer Manufacturing

• Main Authors: TSUNG - JUNG HSIAO, 蕭宗容
• Other Authors: Shih Cheng - Hu
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/77114942706921039179

碩士 === 國立臺北科技大學 === 冷凍與低溫科技研究所 === 90 === This thesis studies the airflow and particle characteristics of a FOUP/LPU (Front Opening Unified Pod / Load Port Unit) minienvironment system using both experiment and Computational Fluid Dynamics (CFD) techniques. The Stochastic Tracking Model, which includes the turbulence effect of the fluctuation velocity was adopted to predict particle trajectory. The predicted velocity vectors were verified by experimental data, which were conducted by a 3D ultrasonic anemometer. The predicted particle characteristics were compared with corresponding particle challenge test results. According to those results, an extracted wafer in the minienvironment, a large vortex is produced below that wafer. This vortex extends to the lower part of the minienvironment and reaches the door opener, and particles within the vortex can be carried to the backside surface of that wafer. Particle generates by the impaction of FOUP door and the Front-Opening Interface Mechanism (FIM) inevitably exhibits great contamination risk on surfaces of FOUP and wafer, especially for particles from the upper edge of the FOUP. Particles generated on the moving part of the LPU were entrained to the backside of the wafer when the wafer was in the bottom position. Shielding cover and local exhausting added to the LPU can effectively control particle dispersion from the LPU. The extent of various parameters that affect the pressure difference between the minienvironment and surrounding environment (i.e cleanroom) were determined and compared. Minimum positive pressure value required to prevent ingression of particles was reported. In general, the thoroughly elucidated information provides by this thesis is useful for mitigating contamination when planning a fabrication line and designing a production tool.