Rotating Disk Reactor With Ferrofluid Seal For Chemical Vapor Deposition

Abstract

A rotating disk reactor for chemical vapor deposition includes a vacuum chamber and a ferrofluid feedthrough comprising an upper and a lower ferrofluid seal that passes a motor shaft into the vacuum chamber. A motor is coupled to the motor shaft and is positioned in an atmospheric region between the upper and the lower ferrofluid seal. A turntable is positioned in the vacuum chamber and is coupled to the motor shaft so that the motor rotates the turntable at a desired rotation rate. A dielectric support is coupled to the turntable so that the turntable rotates the dielectric support when driven by the shaft. A substrate carrier is positioned on the dielectric support in the vacuum chamber for chemical vapor deposition processing. A heater is positioned proximate to the substrate carrier that controls the temperature of the substrate carrier to a desired temperature for chemical vapor deposition.

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         31 . A single substrate carrier for chemical vapor deposition, the substrate carrier comprising:
 a) a body;   b) a top surface having a recessed area for receiving a substrate;   c) a rounded edge having a shape that reduces thermal loss and increases uniformity of process gasses flowing over the substrate;   d) a substantially flat surface at the bottom of the rounded edge for positioning on top of a rotating dielectric support; and   e) a vertical rim positioned proximate to the rounded edge that reduces wobbling of the substrate carrier when positioned on top of the rotating support.   
     
     
         32 . The substrate carrier of  claim 31  wherein the body is circular. 
     
     
         33 . The substrate carrier of  claim 31  wherein the substrate carrier is formed of at least one of graphite, SiC, metal, and ceramic material. 
     
     
         34 . The substrate carrier of  claim 31  wherein the recessed area of the substrate carrier is machined in localized areas to a predetermined depth contour, which results in a desired thermal characteristic across the substrate carrier. 
     
     
         35 . The substrate carrier of  claim 31  wherein the recessed area of the substrate carrier comprises inserts of material in localized areas, which results in a desired thermal characteristic across the substrate carrier. 
     
     
         36 . The substrate carrier of  claim 35  wherein at least one thermal property of the material in the localized area is different from the thermal property of the material forming the substrate carrier. 
     
     
         37 . The substrate carrier of  claim 31  wherein the recessed area of the substrate carrier comprises a multi-level bottom surface. 
     
     
         38 . The substrate carrier of  claim 31  wherein the recessed area comprises tabs for supporting the substrate. 
     
     
         39 . The substrate carrier of  claim 38  wherein the tabs are triangular in shape. 
     
     
         40 . The substrate carrier of  claim 38  wherein the tabs are formed of a material that absorbs at least some force generated when the substrate carrier expands against the substrate. 
     
     
         41 . The substrate carrier of  claim 38  wherein the tabs reduce mechanical stresses on the substrate as the temperature of the substrate carrier increases. 
     
     
         42 . The substrate carrier of  claim 31  wherein the rounded edges are uniformly rounded over the entire edge. 
     
     
         43 . The substrate carrier of  claim 31  wherein the rounded edges are non-uniformly rounded. 
     
     
         44 . The substrate carrier of  claim 31  wherein a weight of the substrate carrier is chosen so that during processing and purging, the substrate carrier is frictionally attached to a top surface of a dielectric support. 
     
     
         45 . The substrate carrier of  claim 31  wherein the vertical rim is dimensioned to secure the substrate carrier on top of a dielectric support at a desired rotation rate. 
     
     
         46 . The substrate carrier of  claim 31  wherein the substrate carrier is formed of material having a thermal expansion coefficient that results in an expansion of the substrate carrier that more tightly holds the substrate carrier on top of the rotating dielectric support. 
     
     
         47 . A multi-substrate carrier for chemical vapor deposition, the multi-substrate carrier comprising:
 a) a body;   b) a top surface having a plurality of recessed areas for receiving a plurality of substrates;   c) a rounded edge having a shape that reduces thermal loss and increases uniformity of process gasses flowing over the plurality of substrates;   d) a substantially flat surface at the bottom of the rounded edge for positioning on top of a rotating dielectric support;   e) a vertical rim positioned proximate to the rounded edge that reduces wobbling of the substrate carrier when positioned on top of the rotating dielectric support; and   f) an attachment for a shaft that rotates the multi-substrate carrier positioned on the bottom surface of the multi-substrate carrier.   
     
     
         48 . The multi-substrate carrier of  claim 47  wherein the body is circular. 
     
     
         49 . The multi-substrate carrier of  claim 47  wherein the multi-substrate carrier is formed of at least one of graphite, SiC, metal, and ceramic material. 
     
     
         50 . The multi-substrate carrier of  claim 47  wherein at least two of the plurality of recessed areas of the multi-substrate carrier have different dimensions. 
     
     
         51 . The multi-substrate carrier of  claim 47  wherein at least one of the recessed areas are machined in localized areas to a predetermined depth contour, which results in a desired thermal characteristic across the multi-substrate carrier. 
     
     
         52 . The multi-substrate carrier of  claim 47  wherein at least one of the recessed area of the multi-substrate carrier comprises inserts of material in localized areas, which results in a desired thermal characteristic across at least a portion of the multi-substrate carrier. 
     
     
         53 . The multi-substrate carrier of  claim 52  wherein at least one thermal property of the material in the localized area is different from the thermal property of the material forming the substrate carrier. 
     
     
         54 . The multi-substrate carrier of  claim 47  wherein at least one of the recessed areas of the substrate carrier comprises a multi-level bottom surface. 
     
     
         55 . The multi-substrate carrier of  claim 47  wherein at least one of the recessed areas comprises tabs for supporting the substrate. 
     
     
         56 . The multi-substrate carrier of  claim 55  wherein the tabs are triangular in shape. 
     
     
         57 . The multi-substrate carrier of  claim 47  wherein the rounded edges are uniformly rounded over the entire edge. 
     
     
         58 . The multi-substrate carrier of  claim 47  wherein the rounded edges are non-uniformly rounded. 
     
     
         59 . The multi-substrate carrier of  claim 47  wherein a weight of the substrate carrier is chosen so that during processing and purging the substrate carrier is frictionally attached to a top surface of a rotating dielectric support. 
     
     
         60 . The multi-substrate carrier of  claim 47  wherein the vertical tab is dimensioned to secure the substrate carrier on top of a rotating dielectric support at a desired rotation rate.