Patent ID: 6271676
Filing Date: 2001-08-07
Classification: H01L,Y10T

Abstract:
A chuck plate assembly comprising:a chuck plate having a first side and a second side opposite said first side;said first side of said chuck plate having a central contact region and a peripheral contact region surrounding said central contact region;said central contact region having a spiral shaped central contact groove formed in said first side of said chuck plate;said peripheral contact region having a spiral shaped peripheral contact groove formed in said first side of said chuck plate;a first plurality of vacuum holes being disposed in said central contact groove;a second plurality of vacuum holes being disposed in said peripheral contact groove;a manifold having a first vacuum reservoir and a second vacuum reservoir;said first vacuum reservoir being in flow communication with said first plurality of vacuum holes;said second reservoir being in flow communication with said second plurality of vacuum holes;said central contact groove being flow isolated from said peripheral contact groove;whereby a vacuum can be created at said central contact region of said chuck plate prior to and independent of a vacuum created at said peripheral contact region.