Dual temperature heater

Abstract

A method and apparatus for heating a substrate in a chamber are provided. an apparatus for positioning a substrate in a processing chamber. In one embodiment, the apparatus comprises a substrate support assembly having a support surface adapted to receive the substrate and a plurality of centering members for supporting the substrate at a distance parallel to the support surface and for centering the substrate relative to a reference axis substantially perpendicular to the support surface. The plurality of the centering members are movably disposed along a periphery of the support surface, and each of the plurality of centering members comprises a first end portion for either contacting or supporting a peripheral edge of the substrate.

1 . An apparatus for positioning a substrate in a processing chamber, comprising:
 a substrate support assembly having a support surface adapted to receive the substrate; and   a plurality of centering members for supporting the substrate at a distance parallel to the support surface and for centering the substrate relative to a reference axis substantially perpendicular to the support surface, wherein the plurality of the centering members are movably disposed along a periphery of the support surface, and each of the plurality of centering members comprises:
 a first end portion for either contacting or supporting a peripheral edge of the substrate, the first end portion comprising:
 an upper end portion extending above the support surface of the substrate support for releasably contacting the peripheral edge of the substrate; 
 a support tab positioned on the upper end portion; and 
 a substrate support notch formed by the intersection of the support tab and the upper end portion, for supporting the substrate, wherein the first end portion is movable between a first position and a second position, a movement from the first position to the second position causes the centering member to release the peripheral edge of the substrate, and a movement from the second position to the first position causes the centering member to push the substrate in a direction toward the reference axis or positions the centering members for supporting the substrate. 
 
   
     
     
         2 . The apparatus of  claim 1 , wherein the substrate support assembly encapsulates at least one embedded heater operable to controllably heat the substrate support assembly and the substrate positioned thereon to a predetermined temperature. 
     
     
         3 . The apparatus of  claim 1 , further comprising a circumscribing shadow frame positioned to prevent deposition on the peripheral edge of the substrate, the support assembly, and the plurality of centering members for reducing flaking and particle contamination in the process chamber. 
     
     
         4 . The apparatus of  claim 2 , further comprising:
 a fiber optic temperature sensor for providing a metric indicative of the temperature profile of the backside of the substrate.   
     
     
         5 . The apparatus of  claim 4 , wherein the fiber optic temperature sensor is positioned in the substrate support assembly. 
     
     
         6 . The apparatus of  claim 2 , further comprising:
 one or more purge gas inlets coupled with a purge gas source for supplying purge gas to a backside of the substrate for preventing particle contamination caused by deposition on the backside of the substrate when the substrate is supported by the centering members.   
     
     
         7 . The apparatus of  claim 6 , wherein the one or more purge gas inlets are positioned in the substrate support assembly. 
     
     
         8 . The apparatus of  claim 1 , further comprising an opposing member for interacting with each of the plurality of centering members to move the first end portion. 
     
     
         9 . The apparatus of  claim 8 , wherein each of the plurality of centering members is pivotally mounted on the substrate support via a shaft. 
     
     
         10 . The apparatus of  claim 9 , wherein the opposing member is configured to move the first end portion of each of the plurality of centering members towards the second position, and each of the plurality of centering members is independently biased towards the first position, and combination of biasing forces from the plurality of centering members centers the substrate relative to the reference axis. 
     
     
         11 . The apparatus of  claim 10 , wherein each of the centering members further comprises:
 a weighted portion eccentric from the shaft, wherein the first end portion and weighted portion are disposed on opposing sides of the shaft, and the weighted portion is configured to bias the centering member into the first position.   
     
     
         12 . The apparatus of  claim 11 , wherein the opposing member comprises a movable member coupled to a motor. 
     
     
         13 . The apparatus of  claim 12 , further comprising a controller configured to monitor an operation signal of the motor, wherein the opposing member is configured to move the first end portion of each of the plurality of centering members towards the first position, and the controller is configured to determine an end point of centering by monitoring the operation signal of the motor. 
     
     
         14 . The apparatus of  claim 1 , wherein each of the centering members is made of a material including ceramic, aluminum nitride, aluminum oxide, aluminum, and combinations thereof. 
     
     
         15 . The apparatus of  claim 1 , wherein the support tabs of each of the plurality of centering members form a substrate receiving pocket for supporting the substrate. 
     
     
         16 . A method for centering a substrate in a processing chamber, comprising:
 providing a substrate support having an embedded heater and a heated support surface adapted to receive a substrate;   providing a plurality of centering members disposed along a circle centered at a reference axis substantially perpendicular to the support surface, each centering member comprising:
 an end portion configured to contact a peripheral edge of the substrate, and the end portion is radially movable towards and away from the reference axis; 
 a support tab positioned on the end portion; and 
 a substrate support notch formed at an intersection of the support tab and the end portion, for supporting the substrate at a distance from the support surface of the substrate support; 
   positioning the substrate on the support tabs of each of the plurality of centering members;   performing a pre-treatment process on the substrate at a first processing temperature of the substrate;   removing the substrate from the support tabs;   moving the end portion of each centering member radially outward and away from the reference axis;   placing the substrate on the substrate support, wherein the substrate and the centering members do not contact;   moving the end portion of each centering members to radially inwards to contact with a peripheral edge of the substrate for centering the substrate;   positioning the substrate with the end portions of the centering members; and   performing a deposition process on the substrate at a second processing temperature of the substrate, wherein the first processing temperature is different than the second processing temperature.   
     
     
         17 . The method of  claim 16 , wherein the distance between the heated support surface and the substrate is selected such that the thermal resistance between the heated support surface and the substrate create a different temperature on the substrate without changing a setpoint temperature of the heater. 
     
     
         18 . The method of  claim 16 , wherein a setpoint temperature of the heater is the same for both the pretreatment process and the deposition process. 
     
     
         19 . The method of  claim 16 , wherein the first processing temperature of the substrate is between about 250° C. and about 270° C. and the second processing temperature of the substrate is between about 350° C. and about 400° C. 
     
     
         20 . The method of  claim 16 , wherein moving the end portion of each centering members comprises pivoting each of the centering members about a shaft mounted on the substrate support. 
     
     
         21 . The method of  claim 16 , wherein moving the end portion of each centering member radially inwards comprises releasing a weighted portion eccentrically coupled to the centering member from the shaft, and moving the end portion of each centering member radially outwards comprising lifting the weight portion with an opposing member. 
     
     
         22 . The method of  claim 16 , wherein moving the end portion of each centering member radially inwards comprises pivoting the centering member from the shaft using an opposing member, and moving the end portion of each centering member radially outwards comprising releasing the centering member from the opposing member. 
     
     
         23 . The method of  claim 22 , wherein moving the end portion of each centering member further comprises:
 monitoring an operational signal of a motor driving the opposing member, wherein the operational signal corresponds to a centering force applied from the centering member to the substrate; and   stopping the opposing member when the centering force reaches a critical value.   
     
     
         24 . The method of  claim 16 , wherein each of the centering members comprises a resilient member biased radially towards the reference axis, and moving the end portion of each centering members radially outwards comprises pushing the resilient member using an opposing member, and moving the end portion of each centering member radially inwards comprising releasing the centering member from the opposing member. 
     
     
         25 . The method of  claim 16 , wherein pivoting the centering members comprises interacting the centering members with an opposing member.