| 摘要 |
<p>In a plasma processing system for processing substrates such as semiconductor wafers, deposition of polymer in an area (30) between a focus ring (16) and an electrostatic chuck (14) in a plasma processing chamber (10) is achieved by providing a clearance gas in a gap between the chuck and the focus ring. A series of channels delivers the clearance gas to the annular gap between the outer surface of the substrate support and the inner surface of the focus ring surrounding the substrate support. The clearance gas supplied to the annular gap is preferably a gas such as helium which will not affect the wafer processing operation. In the case of plasma etching, the clearance gas is supplied at a flow rate which is sufficient to block the migration of process gas and volatile by products thereof into the annular gap without adversely affecting edge etch performance.</p> |
