Method and apparatus for clamping a substrate in a high pressure processing system
AssigneeTokyo Electron Limited
InventorAlexei Sheydayi
Life of this patent
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Abstract
An isolated semiconductor wafer platen is disclosed for use in high pressure processing. The use of vacuum chucking for holding a semiconductor wafer during processing is well known in the art and can be applied to high pressure systems as well, but some difficulties can arise under high pressure processes. Small deflections in even very thick metal support platens can lead to backside wafer wear, platen abrasion, and even breakage of semiconductor wafers. This invention discloses a method to eliminate the transfer of flexure inherent in high pressure vessel walls, yet still retain the vacuum chucking method.
Claims17
A wafer holder for holding a semiconductor wafer by fluid pressure bias when processing the wafer in a processing chamber with a high pressure fluid, the wafer holder comprising:
- a platen disk having a backside, a frontside, and a wafer supporting surface on the frontside thereof, the disk having passages therein communicating with the wafer supporting surface, the passages being located such that, when relatively low pressure is applied therethrough to the backside of a wafer supported on the wafer supporting surface, the high pressure fluid in the chamber holds the wafer for processing against the wafer supporting surface;
- and
- a pressure plate having a body sufficiently rigid to resist deformation when subjected to the high pressure fluid, said pressure plate having a cavity therein configured to receive the platen disk, the cavity being sufficiently larger than the platen disk to form a gap between the disk and the pressure plate to allow the high pressure fluid therein;
- whereby said gap communicates the high pressure of the high pressure fluid against said pressure plate substantially isolating said platen disk from a substantial pressure gradient between the frontside and backside thereof.
A method of holding a semiconductor wafer to a platen in a high pressure fluid processing chamber comprising:
- providing a rigid pressure plate between a high pressure fluid and an ambient atmosphere in the bottom of a processing chamber;
- supporting a platen disk on the pressure plate in the processing chamber;
- supporting a wafer on an upwardly facing surface of the platen disk;
- applying a vacuum to the backside of the supported wafer through passages within the platen disk;
- and
- substantially surrounding the underside of the platen disk with fluid at the pressure of high pressure fluid in the chamber.
A processing system for treating a substrate comprising:
- a processing chamber configured to treat said substrate therein with a high pressure fluid;
- a platen coupled to said processing chamber and configured to support said substrate;
- a fluid supply system;
- a chuck coupled to said platen and configured to hold said substrate against said platen by a pressure gradient between said high pressure fluid and said platen;
- and
- means for substantially surrounding said platen with the high pressure fluid.
Dependencies are inferred from the claim text.