Method and structure for improving heat transfer fluid flow in electrostatic chucks

摘要

The present invention discloses a basic structure and a method for fabrication of the structure which facilitates the flow of cooling gas or other heat transfer fluid to the surface of an electrostatic chuck. The basic structure addresses the problem of the rf plasma environment which seeks the interface between the electrostatic chuck dielectric surface layer and its underlying conductive layer. The basic structure includes an underlying conductive layer which contains at least one gas flow passageway (112) and at least one dielectric layer (114) overlying said conductive layer. The dielectric layer forms the upper surface of the dielectric chuck and contains at least one opening or passageway (116) which connects with the fluid flow passageway in the conductive layer. The dielectric layer thickness is greater in the area of the opening or passageway than at other locations on the surface of the dielectric chuck The basic structure provides an insulative dielectric structure (114) as the upper surface of the electrostatic chuck and improves the isolation of the electrostatic chuck dielectric surface from the underlying conductive layer. Typically, the conductive layer is an aluminium pedestal (204) and the overlaying dielectric layer is a spray-applied alumina. Other materials of construction can be used so long as they meet electrical requirements and their relative thermal coefficients of expansion do not create problems in the integrity of the electrostatic chuck after multiple cycles in the intended processing environment. <IMAGE>