Patent ID: 6436192
Filing Date: 2002-08-20
Classification: C23C,H01L

Abstract:
An apparatus for aligning a wafer in a processing chamber, comprising:a support member positioned within the processing chamber and having a wafer receiving surface thereon; a shadow ring located within the processing chamber, the shadow ring comprising: an upper shield portion defining a circular upper aperture therethrough, the upper aperture having an inner diameter and a wafer shielding surface disposed outwardly from the inner diameter of the upper shield portion; a lower portion extending from the upper shield portion and having an annular cross section defining a frustoconical inner cavity, wherein the diameter of the inner cavity decreases from a lower aperture to an upper end, and the diameter of the upper end of the inner cavity is greater than the inner diameter of the shield portion; a gas supply in fluid communication with the processing chamber; and a gas flow controller having a predetermined set of instructions to regulate pressure within the processing chamber such that, after a wafer is positioned on the support member and before the wafer is raised into the shadow ring, the predetermined set of instructions direct the gas flow controller to increase the pressure within the processing chamber and to provide a pressure between the wafer and support member to a pressure greater than or equal to the pressure within the processing chamber to align the wafer with the shadow ring and support member.