AVS 61st International Symposium & Exhibition
    Vacuum Technology Tuesday Sessions
       Session VT-TuM

Invited Paper VT-TuM12
Advanced High Speed Water Vapor Cryopumps: Enabling Today’s Vacuum Processes

Tuesday, November 11, 2014, 11:40 am, Room 303

Session: Gas Dynamics, Modeling, and Pumping Systems
Presenter: Kevin Flynn, Brooks Automation, Inc., Polycold
Authors: K. Flynn, Brooks Automation, Inc., Polycold
C. Rebecchi, Brooks Automation, Inc., Polycold
Correspondent: Click to Email
Effective and efficient pumping of water vapor in vacuum systems via cryopumps or cryotraps is critical to achieving required vacuum system performance for many processes. A brief over view of general cryopumping methods is presented along with an in depth review of water vapor cryopumping. Water is of special importance due to its difficulty to be pumped, its deleterious impact on coatings when it remains on the substrate, and its ability to form oxygen which reacts with and degrades thin film quality. In addition to the basic pumping function, the ability of a cryopump to rapidly cool and defrost or regenerate the cryosurface are important for enabling high chamber productivity. Required water vapor partial pressures vary widely among typical vacuum processes, ranging from 10-1 torr to below 10-9 torr. Similarly required pumping speeds range from thousands of liters per second to over 200,000 liters per second. The combination of these varying requirements drive different demands for cryopump cooling capacity and temperatures. A variety of different vacuum applications covering medium, high and ultra high vacuum applications, and including batch and inline processes, are reviewed along with considerations of cryosurface location relative to the chamber and process.