AVS 45th International Symposium
    Manufacturing Science and Technology Group Monday Sessions
       Session MS-MoA

Paper MS-MoA9
Gradational Lead Screw Pump Development

Monday, November 2, 1998, 4:40 pm, Room 317

Session: Contamination Free Manufacturing
Presenter: K. Ando, T.D.Giken Co., Ltd., Japan
Authors: K. Ando, T.D.Giken Co., Ltd., Japan
I. Akutsu, DIAVAC Limited, Japan
T. Ohmi, Tohoku University, Japan
Correspondent: Click to Email
Because the silicone device industry is innovating their production processes toward the larger wafer size and the higher process speed, a vacuum pump is required higher pumping speed through ranges of the both viscous and molecular flow. There has been no known conventional pumps that have been developed so as to vacuum a chamber down to 0.01 Torr with stable exhaust velocity over the entire region including the molecular flow region. All of them provide stable pumping speed only down to 0.1 Torr. The "GLS Pump" unlike these conventional pumps demonstrated the high pumping capability of 0.0004 Torr and the pumping speed of 3600L/M over the viscous and molecular flow ranges. The improved performance is attributable to the GLS employed for the rotor design. The pump utilizes a small amount of oil. The mass analyzer test(max. mass number 120) revealed that there is no evidence of the reverse diffusion in the pressure range above 0.002 Torr with a small amount of N2gas injected. In summary, the GLS Pump has enough displacement and large intake conductance. Low reverse diffusion is in practical operation. The pumping speed is high. The power consumption is low. The byproduct is transferred and ejected from the exhaust port through the operation mechanism. The radical deposit is minimized if the case temperature is maintained at 150°C. Although manufacturing this pump requires high level of skill, the pump structure is rather simple and the maintenance is easy hence it will increase the mean time between maintenance and reduce the maintenance cost. The detail report will be prepared on the characteristics of the GLS, the pump structure, and the performance attributes.