Sealing device and method useful in semiconductor processing apparatus for bridging materials having a thermal expansion differential

Abstract

Apparatus for promoting heat transfer between a first volume (chamber volume) and a second volume (expandable, substrate support platform volume). Specifically, the apparatus comprises: a chamber defining a chamber volume that contains a chamber atmosphere, e.g., a partial vacuum; a substrate support platform that defines an expandable volume that contains a heat transfer medium, e.g., air; and a seal that isolates the chamber volume from the heat transfer medium. The substrate support platform further comprises: a substrate support platen that has a first surface located within the chamber volume and a second surface located within the expandable volume; a housing sealed to the second surface of the substrate support platen; and a expandable member such as a bellows, attached to the housing, to provide for expansion of the expandable volume that is defined by the housing and the bellows. The housing is typically fabricated of metal and the substrate support is typically fabricated of ceramic. The seal forms a hermetic junction between the ceramic substrate support and the metal housing.

What is claimed is:  
     
         1 . A sealing apparatus useful in a semiconductor processing when a first portion of a semiconductor processing chamber is operated at one pressure while a second portion of said processing chamber is operated at a higher pressure and when said sealing apparatus is used to isolate said first and second portions of said process chamber, said sealing apparatus comprising: a thin, metal-comprising layer brazed to at least two different surfaces, wherein said at least two different surfaces exhibit a difference in linear thermal expansion coefficient of at least 3×10 −3  in./in./° C., measured at 600° C.  
     
     
         2 . The sealing means of    claim 1   , wherein a brazing material is used to provide a filler between said metal-comprising layer and each of said at least two different surfaces.  
     
     
         3 . The sealing apparatus of    claim 2   , wherein said brazing material is metal-comprising and is capable of stress relaxation.  
     
     
         4 . The sealing apparatus of    claim 1   , or    claim 2   , wherein a cross-sectional thickness (a) of said thin, metal-comprising layer is less than about 0.039 in.  
     
     
         5 . The sealing apparatus of    claim 4   , wherein said metal-comprising layer is in the form of a ribbon.  
     
     
         6 . The sealing apparatus of    claim 4   , wherein said metal-comprising layer is in the form of a band.  
     
     
         7 . The sealing means of    claim 5   , wherein said ribbon has an accordion shape.  
     
     
         8 . The sealing apparatus of    claim 6   , wherein said band has an accordion shape.  
     
     
         9 . The sealing apparatus of    claim 1   , wherein said sealing apparatus is capable of withstanding a pressure differential of at least 15 psi over an operating temperature range between about 0° C. and about 600° C., while bridging said at least two materials having said difference in thermal expansion coefficient.  
     
     
         10 . The sealing apparatus of    claim 5   , wherein said sealing apparatus is capable of withstanding a pressure differential of at least 15 psi over an operating temperature range between about 0° C. and about 600° C., while bridging said at least two materials having said difference in linear expansion coefficient.  
     
     
         11 . The sealing apparatus of    claim 6   , wherein said sealing apparatus is capable of withstanding a pressure differential of at least 15 psi over an operating temperature range between about 0° C. and about 600° C., while bridging said at least two materials having said difference in linear expansion coefficient.  
     
     
         12 . The sealing apparatus of    claim 1   , wherein said first portion of said semiconductor processing chamber includes an upper surface of an electrostatic chuck which contacts a substrate to be processed.  
     
     
         13 . The sealing apparatus of    claim 12   , wherein said second portion of said processing chamber includes a means of conductive/convective heat transfer to permit cooling of a lower surface of said electrostatic chuck.  
     
     
         14 . A method of providing a seal between adjacent surfaces of a semiconductor processing apparatus, which method enables the operation of one portion of a semiconductor processing chamber at one pressure while another portion of said processing chamber is operated at a higher pressure, wherein said seal bridges at least two surfaces which exhibit different linear thermal expansion coefficients and when the operational temperature range of said processing chamber is at least 300° C., said method comprising: 
 a) providing at least two material surfaces which exhibit a different thermal expansion coefficient;  
 b) providing a thin, metal-comprising layer of material having a linear coefficient of expansion closer to the lowest linear thermal expansion coefficient material to be bridged;  
 c) brazing said metal-comprising layer of material to each of the at least two material surfaces which must be-bridged by said seal, whereby said metal-comprising layer, a brazing material, and said material surfaces to which the metal-comprising layer is braised act as a sealing apparatus.  
 
     
     
         15 . The method of    claim 14   , wherein said brazing is carried out using a brazing material capable of relaxing stress.  
     
     
         16 . The method of    claim 14   , wherein said difference in thermal expansion coefficient is at least 3×10 −3  in./in./° C. at about 600° C.  
     
     
         17 . An apparatus which can be used in combination with a substrate support platen in semiconductor processing to capture back-scattered deposition materials and prevent the need to clean outer edges of said support platen, said apparatus comprising a removable insert which is located at said outer edges of said support platen.  
     
     
         18 . The apparatus of    claim 17   , wherein the thermal expansion coefficient of said removable insert is sufficiently close to the thermal expansion coefficient of said platen that the creation of significant stresses between said insert and said platen surface is avoided.