Performance and improvement of cleanroom environment control system related to cold-heat offset in clean semiconductor fabs

Abstract

Clean room is a key technology to guarantee the normal operation in semiconductor manufacturing industry. On-site measurement of indoor environment and performances of the air conditioning systems in four clean semiconductor fabs have been conducted in summer in this study. It's indicated that indoor environment of these four fabs all meet the requirement and a satisfied control accuracy is achieved. The main energy-consuming facilities in the air conditioning system arises from the fan of air handling processors and chillers, which consumes about 80%–90% of the total. Reheating in make-up air handing process (MAU) occurs in the current system, resulting in cold-heat offset and extra energy loss. System schematic avoiding reheating based on the measured results is proposed. The proposed system where only part of indoor return air is cooled by the dry cooling coil (DCC) and achieves secondary return air could avoid the cold-heat offset. At full load condition, cooling supplies for DCC (QDCC) in the proposed system is about 40%–52% lower than that in the current system of these four fabs. No reheating exists in the proposed system, and QRH is saved 151–236 W/m2. The research helps to reveal the operating performance and propose appropriate improving approaches for these circumstances.