Dry pumps operating under harsh conditions in the semiconductor industry

Abstract

The ability of ‘‘dry’’ primary vacuum pumps of the roots/claw configuration to handle semiconductor processes which previously could be pumped only with very frequent maintenance and great expense, has represented a quantum advance in pumping technology. A detailed knowledge of the mechanism by which dusty by-products are generated and transported through the machine, together with the characteristics of particulate deposition, is required when such pumps are serving production wafer-processing equipment. Experiments are described which detail the performance of a pump under conditions of high rates of dust loading together with techniques, by which reliability can be enhanced.

The Low-Pressure Gas and Vacuum Processing Environment

“…[81]- [85] In addition, they are relatively oil-free thus avoiding the potential of oil contamination in the deposition system. [81]- [85] In addition, they are relatively oil-free thus avoiding the potential of oil contamination in the deposition system.…”

Fuzzy model-based condition monitoring of a dry vacuum pump via time and frequency analysis of the exhaust pressure signal

“…Roots and claw dry pumps such as the one used in this research are a generally reliable design and the absence of sealing fluid reduces the risk of process contamination. However aggressive process chemistry and the presence of solid particulates in the pumped gas can cause seizure of the pump or blockage of the exhaust system [2,3]. A characteristic of dry vacuum pump operation is a low net mass flowrate of gas, meaning that deposits can drastically reduce the effective diameter of the flow path through the exhaust system without significantly affecting the average exhaust pressure.…”

“…The need for increased reliability and capability for self-diagnosis in vacuum pumps was identified by Troup and Dennis [4]. As the relative cost of processing power decreases, schemes, which provide continuous condition and process monitoring are finding wide favour in the industry [2,5]. This paper presents an algorithm for condition monitoring of the vacuum pump system based on signals from practical and cost-effective transducers.…”

Thermodynamic analysis of the rotary tooth compressor

“…Wycliffe [2] reported studies on this machine as an oil-free vacuum pump in 1987. Troup and Turrell [3] compared the rotary tooth pump with the Roots pump in applications with harsh conditions in 1989. Troup and Dennis [4] analysed its characteristics in a review paper in 1991.…”