Pedestal construction with low coefficient of thermal expansiion top

Abstract

A support assembly for use in semiconductor processing includes an application substrate, a heater layer disposed directly on the application substrate, an insulation layer disposed on the heater layer, and a second substrate disposed on the insulation layer. The heater layer is directly disposed on the application substrate by a layered process such that the heater layer is in direct contact with the application substrate. The application substrate defines a material having a relatively low coefficient of thermal expansion that is matched to a coefficient of thermal expansion of the heater layer. A periphery of the second substrate extends beyond a periphery of the application substrate.

What is claimed is: 
     
         1 . A support assembly for use in semiconductor processing, the support assembly comprising:
 an application substrate;   a heater layer disposed directly on the application substrate by a layered process such that the heater layer is in direct contact with the application substrate;   an insulation layer disposed on the heater layer; and   a second substrate disposed on the insulation layer,   
       wherein the application substrate defines a material having a relatively low coefficient of thermal expansion that is matched to a coefficient of thermal expansion of the heater layer, and 
       wherein a periphery of the second substrate extends beyond a periphery of the application substrate. 
     
     
         2 . The support assembly according to  claim 1 , wherein the layered process is selected from a group consisting of thick film, thin film, thermal spray, and sol-gel processes. 
     
     
         3 . The support assembly according to  claim 1 , wherein the application substrate is operable to function as an interface to be bonded to a heating substrate by a thermal process. 
     
     
         4 . The support assembly according to  claim 3 , wherein the heating substrate is positioned on the top surface of the application substrate during processing, and the top surface has a chemically isolating layer between the application substrate and the heating substrate. 
     
     
         5 . The support assembly according to  claim 1 , wherein the heater layer is secured to the application substrate by a process selected from the group consisting of MIG, TIG, laser, electron beam welding, brazing, diffusion bonding, and adhesive bonding. 
     
     
         6 . The support assembly according to  claim 1  further comprising a pedestal connected to the second substrate. 
     
     
         7 . A support assembly for use in semiconductor processing, the support assembly comprising:
 an application substrate;   a heater layer disposed directly on the application substrate by a layered process such that the heater layer is in direct contact with the application substrate;   an insulation layer disposed on the heater layer; and   a second substrate disposed on the insulation layer,   
       wherein the application substrate defines a material having a relatively low coefficient of thermal expansion that is matched to a coefficient of thermal expansion of the heater layer, and 
       wherein the second substrate includes a base portion and a peripheral portion surrounding the base portion, the peripheral portion extends vertically and upwardly from the base portion, and a top surface of the peripheral portion is lower than a top surface of the application substrate and is exposed from the top surface of the application substrate. 
     
     
         8 . The support assembly according to  claim 7 , wherein the layered process is selected from a group consisting of thick film, thin film, thermal spray, and sol-gel processes. 
     
     
         9 . The support assembly according to  claim 7 , wherein the second substrate is a gas-distributing substrate for providing a purging gas. 
     
     
         10 . The support assembly according to  claim 7 , wherein the second substrate is a cooling substrate for cooling the application substrate. 
     
     
         11 . The support assembly according to  claim 7 , further comprising a pedestal connected to the second substrate. 
     
     
         12 . The support assembly according to  claim 11 , further comprising a gas conduit received in the pedestal to provide purge gas to the second substrate. 
     
     
         13 . The support assembly according to  claim 7 , wherein the application substrate defines a plurality of vacuum clamping channels. 
     
     
         14 . The support assembly according to  claim 7 , wherein the application substrate defines lift pin holes for receiving proximity pins. 
     
     
         15 . The support assembly according to  claim 14 , wherein the proximity pins are movable to support a wafer and to place the wafer on the application substrate. 
     
     
         16 . A support assembly for use in semiconductor processing, the support assembly comprising:
 a tubular pedestal;   a gas-distributing substrate connected to the tubular pedestal;   a heater layer provided on the gas-distributing substrate for heating a wafer; and   an application substrate disposed on the heater layer and including controlled expansion alloy that has a variable composition with a coefficient of thermal expansion compatible with that of the heater layer,   
       wherein a periphery of the gas-distributing substrate extends beyond a periphery of the application substrate. 
     
     
         17 . The support assembly according to  claim 16 , wherein the gas-distributing substrate includes a base portion and a peripheral portion surrounding the base portion and extending vertically and upwardly from the base portion such that the peripheral portion extends beyond the periphery of the application substrate. 
     
     
         18 . The support assembly according to  claim 16 , wherein the application substrate functions as an interface to be bonded to a heating substrate by a thermal process. 
     
     
         19 . The support assembly according to  claim 16 , wherein the layered process is selected from a group consisting of thick film, thin film, thermal spray, and sol-gel processes. 
     
     
         20 . The support assembly according to  claim 16 , further comprising a gas conduit received in the pedestal for supplying a purge gas to the gas-distributing substrate.