Substrate support providing gap height and planarization adjustment in plasma processing chamber

Abstract

A semiconductor substrate support for use in a plasma processing apparatus comprises a chuck body having a plenum and three radially extending bores extending between the plenum and an outer periphery of the chuck body, wherein the chuck body is sized to support a semiconductor substrate having a diameter of at least 450 mm. The semiconductor substrate support further comprises three tubular support arms which include a first section extending radially outward from the outer periphery of the chuck body, and a second section extending vertically from the first section. The tubular support arms provide a passage therethrough which communicates with a respective bore in the chuck body. The second section of each tubular support arm is configured to engage with a respective actuation mechanism outside the chamber operable to effect vertical translation and planarization of the chuck body in the interior of a plasma processing chamber.

What is claimed is: 
     
       1. A semiconductor substrate support for use in a plasma processing apparatus comprising:
 a chuck body having a plenum and three radially extending bores extending between the plenum and an outer periphery of the chuck body, the chuck body sized to support a semiconductor substrate having a diameter of at least 450 mm; and 
 three tubular support arms attached to the chuck body, each of the tubular support arms including a first section extending radially outward from the outer periphery of the chuck body and a second section extending vertically from the first section, each of the tubular support arms defining a passage in communication with one of the bores, each of the second sections configured to engage with a respective actuation mechanism operable to effect vertical translation for gap height and planarization adjustment of the chuck body. 
 
     
     
       2. The semiconductor substrate support of  claim 1 , wherein the first sections of the tubular support arms extend outward either perpendicularly or at an angle to a vertical axis passing through the center of the chuck body. 
     
     
       3. The semiconductor substrate support of  claim 1 , wherein the second sections of the tubular support arms extend from the respective first sections of the tubular support arms vertically above the chuck body or extend from the respective first sections of the tubular support arms vertically below the chuck body. 
     
     
       4. The semiconductor substrate support of  claim 1 , wherein the tubular support arms are circumferentially spaced apart forming three angles therebetween, two of the angles being between 120 and 165 degrees and the a third angle being between 35 and 120 degrees. 
     
     
       5. A capacitively-coupled plasma processing apparatus comprising:
 a vacuum chamber; 
 the semiconductor substrate support of  claim 1  in an interior of the vacuum chamber; 
 an upper showerhead electrode assembly supported by a top wall of the vacuum chamber; 
 a lower electrode assembly incorporated in the semiconductor substrate support wherein the lower electrode assembly comprises a lower electrode and an electrostatic chuck (ESC) having a support surface on which the semiconductor substrate is supported; 
 three openings in an outer wall of the vacuum chamber in which the second sections of the tubular support arms are located; 
 three actuation mechanisms on the outer wall and connected to the second sections of the tubular support arms, the three actuation mechanisms operable to independently move the tubular support arms in upward and downward directions; 
 at least one vacuum port in a bottom wall connected to at least one vacuum pump operable to maintain the vacuum chamber at a predetermined vacuum pressure; and 
 a gas source operable to supply process gas through the upper showerhead electrode assembly to the vacuum chamber. 
 
     
     
       6. The capacitively-coupled plasma processing apparatus of  claim 5 , wherein an expandable vacuum seal seals each opening in the outer wall and maintains a vacuum tight seal between an outer periphery of each tubular support arm and the outer wall such that each tubular support arm may be vertically translated by the respective actuation mechanism without exposing the interior of the vacuum chamber to atmospheric pressure. 
     
     
       7. The capacitively-coupled plasma processing apparatus of  claim 5 , wherein the three actuation mechanisms are independently controllable with respect to each other to effect a predetermined gap height between the upper showerhead electrode assembly and the support surface of the ESC and a predetermined planarization of the support surface of the ESC. 
     
     
       8. The capacitively-coupled plasma processing apparatus of  claim 7 , wherein each actuation mechanism comprises a stepper motor coupled to a mount on the outer wall of the vacuum chamber, the mount affixed to the respective tubular support arm such that the tubular support arm is movably located in the respective opening in the outer wall of the vacuum chamber. 
     
     
       9. The capacitively-coupled plasma processing apparatus of  claim 6 , wherein the three actuation mechanisms are located on a top surface of the top wall of the vacuum chamber. 
     
     
       10. The capacitively-coupled plasma processing apparatus of  claim 6 , wherein the three actuation mechanisms are located on a bottom surface of the bottom wall of the vacuum chamber. 
     
     
       11. The capacitively-coupled plasma processing apparatus of  claim 5 , wherein the vacuum chamber includes two vacuum ports in the bottom wall of the vacuum chamber, the bottom wall being separated from the semiconductor substrate support by an open area, the vacuum ports being connected to two vacuum pumps which remove gases from the interior of the vacuum chamber and maintain the interior of the vacuum chamber at a pressure below 500 mTorr. 
     
     
       12. The capacitively-coupled plasma processing apparatus of  claim 5 , wherein the semiconductor substrate support includes a plurality of service conduits extending through one or more of the passages of the tubular support arms into the chuck body through the radially extending bores, the service conduits supplying at least one of a heat transfer gas, temperature controlled liquid coolant, RF energy, pressurized air, electrical monitoring signals or electrical actuating signals to or from the chuck body. 
     
     
       13. The capacitively-coupled plasma processing apparatus of  claim 5 , wherein the lower electrode is coupled to a radio frequency (RF) power supply via an RF transmission member extending through one of the tubular support arms. 
     
     
       14. The capacitively-coupled plasma processing apparatus of  claim 13 , wherein only the RF transmission member is located in one of the tubular support arms, and service conduits for supplying at least one of a heat transfer gas, temperature controlled liquid, pressurized air, electrical monitoring signals, or electrical actuating signals to or from the chuck body are located in one or more of the other tubular support arms. 
     
     
       15. The capacitively-coupled plasma processing apparatus of  claim 5 , wherein the upper showerhead electrode assembly includes a C-shaped confinement ring positioned about the a periphery of the upper showerhead electrode assembly and the lower electrode assembly within the vacuum chamber, the C-shaped confinement ring enclosing substantially all of an inter-electrode volume between the upper showerhead electrode assembly and lower electrode assembly and comprising a plurality of openings, each of the openings extending substantially a length of an inter-electrode gap between the planar surfaces of the upper showerhead electrode assembly and the support surface of the ESC and facilitating gas exhaustion from the inter-electrode volume to the remaining volume of the vacuum chamber. 
     
     
       16. The capacitively-coupled plasma processing apparatus of  claim 5 , wherein the lower electrode assembly further comprises a temperature controlled base plate. 
     
     
       17. The capacitively-coupled plasma processing apparatus of  claim 5 , wherein the vacuum chamber includes a cylindrical inner wall with three vertical channels extending into the cylindrical inner wall, the tubular support arms located in and movable vertically in the vertical channels. 
     
     
       18. A The capacitively-coupled plasma processing apparatus according to  claim 5 , further including a control system in electrical communication with said actuation mechanisms for controlling gap height and planarization. 
     
     
       19. The capacitively-coupled plasma processing apparatus of  claim 18 , further comprising at least one laser interferometer, the laser interferometer providing signals to the control system to effect real time measurements of the gap height and the planarization between the upper showerhead electrode assembly and the support surface of the ESC. 
     
     
       20. The capacitively-coupled plasma processing apparatus of  claim 19 , wherein the control system controls the actuation mechanisms to adjust in situ, gap height and planarization between the upper showerhead electrode assembly and the support surface of the ESC to effectuate uniform etching of the semiconductor substrate based on the measurements taken by the at least one laser interferometers. 
     
     
       21. A method of etching a semiconductor substrate in a the capacitively-coupled plasma processing apparatus according to  claim 5  comprising:
 placing a the semiconductor substrate on the support surface of the ESC inside the vacuum chamber; 
 vertically translating the semiconductor substrate support to achieve a predetermined gap height between the semiconductor substrate and a bottom surface of the upper showerhead electrode assembly; 
 measuring planarization between the semiconductor substrate and the bottom surface of the upper showerhead electrode assembly to determine if desired planarization between said the semiconductor substrate and the upper showerhead electrode assembly exists; 
 adjusting in-situ the planarization of the semiconductor substrate relative to the bottom surface of the upper showerhead electrode assembly; 
 supplying a gas into the vacuum chamber from a gas supply; and 
 energizing the gas into a plasma state and etching the semiconductor substrate with the plasma. 
 
     
     
       22. The method of  claim 21 , wherein the in-situ planarization of the semiconductor substrate is adjusted during the plasma etching. 
     
     
       23. A substrate support of a substrate processing apparatus comprising: a substrate support configured to support a substrate on an upper surface thereof; and three tubular support arms attached to the substrate support, each of the tubular support arms configured to engage via a mounting arrangement with a respective actuation mechanism operable to effect gap height and planarization adjustment of the substrate support, each mounting arrangement including a ball in contact with a different geometric shape.  
     
     
       24. The substrate support of claim 23, wherein the three tubular support arms each include a first section extending radially outward from an outer periphery of the substrate support and a second section extending vertically from the first section.  
     
     
       25. The substrate support of claim 24, wherein the first sections of the tubular support arms extend outward either perpendicularly or at an angle to a vertical axis passing through the center of the substrate support.  
     
     
       26. The substrate support of claim 24, wherein the second sections of the tubular support arms extend from the respective first sections of the tubular support arms vertically above the substrate support or extend from the respective first sections of the tubular support arms vertically below the substrate support.  
     
     
       27. The substrate support of claim 23, wherein the substrate support has a plenum and three radially extending bores extending between the plenum and an outer periphery of the substrate support wherein each of the tubular support arms defines a passage that is in communication with a respective bore.  
     
     
       28. The substrate support of claim 23, wherein the tubular support arms are circumferentially spaced apart forming three angles therebetween, two of the angles being 120 to 165 degrees and a third angle being 35 to 120 degrees.  
     
     
       29. The substrate support of claim 23, further comprising a lower electrode assembly incorporated therein wherein the lower electrode assembly includes a lower electrode.  
     
     
       30. The substrate support of claim 23, further comprising an electrostatic chuck (ESC) therein.  
     
     
       31. A substrate processing apparatus comprising: a vacuum chamber; a substrate support in an interior of the vacuum chamber wherein the substrate support comprises a lower electrode and is configured to support a substrate on an upper surface thereof and three tubular support arms attached to the substrate support; an upper showerhead assembly supported by a top wall of the vacuum chamber; three openings in an outer wall of the vacuum chamber in which sections of the tubular support arms are located; three actuation mechanisms on the outer wall wherein each actuation mechanism is connected to a respective tubular support arm, the three actuation mechanisms operable to independently move the respective tubular support arms in upward and downward directions to adjust a gap height between the lower electrode and a showerhead electrode distributing gas in the substrate processing apparatus; at least one vacuum port in a bottom wall connected to at least one vacuum pump operable to maintain the vacuum chamber at a predetermined vacuum pressure; and a gas source operable to supply process gas through the upper showerhead assembly to the vacuum chamber.  
     
     
       32. The substrate processing apparatus of claim 31, further comprising a lower electrode assembly incorporated in the substrate support wherein the lower electrode assembly includes a lower electrode.  
     
     
       33. The substrate processing apparatus of claim 32, wherein the lower electrode is coupled to a radio frequency (RF) power supply via an RF transmission member extending through one of the tubular support arms.  
     
     
       34. The substrate processing apparatus of claim 32, wherein the lower electrode assembly further comprises a temperature controlled base plate.  
     
     
       35. The substrate processing apparatus of claim 31, further comprising an electrostatic chuck (ESC) in the substrate support.  
     
     
       36. The substrate processing apparatus of claim 31, wherein the upper showerhead assembly is an upper showerhead electrode assembly.  
     
     
       37. The substrate processing apparatus of claim 36, including a C-shaped confinement ring positioned about a periphery of the upper showerhead electrode assembly and a lower electrode assembly incorporated in the substrate support within the vacuum chamber, the C-shaped confinement ring enclosing substantially all of an inter-electrode volume between the upper showerhead electrode assembly and the lower electrode assembly and comprising a plurality of openings, each of the openings extending substantially a length of an inter-electrode gap between a plasma exposed surface of the upper showerhead electrode assembly and the upper surface of the substrate support and facilitating gas exhaustion from the inter-electrode volume to the remaining volume of the vacuum chamber.  
     
     
       38. The substrate processing apparatus of claim 31, wherein an expandable vacuum seal seals each opening in the outer wall and maintains a vacuum tight seal between an outer periphery of each tubular support arm and the outer wall such that each tubular support arm may be moved by the respective actuation mechanism without exposing the interior of the vacuum chamber to atmospheric pressure.  
     
     
       39. The substrate processing apparatus of claim 31, wherein the three actuation mechanisms are independently controllable with respect to each other to effect a predetermined gap height between a lower surface of the upper showerhead assembly and the upper surface of the substrate support and a predetermined planarization of the upper surface of the substrate support.  
     
     
       40. The substrate processing apparatus of claim 39, wherein each actuation mechanism comprises a stepper motor coupled to a mount on the outer wall of the vacuum chamber, the mount affixed to the respective tubular support arm such that the tubular support arm is movably located in the respective opening in the outer wall of the vacuum chamber.  
     
     
       41. The substrate processing apparatus of claim 31, wherein the three actuation mechanisms are located on a top surface of the top wall of the vacuum chamber.  
     
     
       42. The substrate processing apparatus of claim 31, wherein the three actuation mechanisms are located on a bottom surface of the bottom wall of the vacuum chamber.  
     
     
       43. The substrate processing apparatus of claim 31, wherein the vacuum chamber includes two vacuum ports in the bottom wall of the vacuum chamber, the bottom wall being separated from the substrate support by an open area, the vacuum ports being connected to two vacuum pumps configured to remove gases from the interior of the vacuum chamber.  
     
     
       44. The substrate processing apparatus of claim 31, wherein one or more of the tubular support arms includes one or more service conduits extending therethrough, the service conduits supplying at least one of a heat transfer gas, temperature controlled liquid coolant, RF energy, pressurized air, electrical monitoring signals or electrical actuating signals to or from the substrate support.  
     
     
       45. The substrate processing apparatus of claim 33, wherein only the RF transmission member is located in one of the tubular support arms, and service conduits for supplying at least one of a heat transfer gas, temperature controlled liquid, pressurized air, electrical monitoring signals, or electrical actuating signals to or from the substrate support are located in one or more of the other tubular support arms.  
     
     
       46. The substrate processing apparatus of claim 31, wherein the vacuum chamber includes a cylindrical inner wall with three vertical channels extending into the cylindrical inner wall, the tubular support arms located in and movable in the vertical channels.  
     
     
       47. The substrate processing apparatus according to claim 31, further including a control system in electrical communication with said actuation mechanisms operable to control gap height between a lower surface of the upper showerhead assembly and the upper surface of the substrate support and planarization of the upper surface of the substrate support.  
     
     
       48. The substrate processing apparatus of claim 47, further comprising at least one laser interferometer, the at least one laser interferometer providing signals to the control system to effect real time measurements of the gap height between the lower surface of the upper showerhead assembly and the upper surface of the substrate support and the planarization of the upper surface of the substrate support.  
     
     
       49. The substrate processing apparatus of claim 48, wherein the control system controls the actuation mechanisms to adjust in-situ, gap height and planarization between the lower surface of the upper showerhead assembly and the upper surface of the substrate support to effectuate uniform processing of the substrate based on the measurements taken by the at least one laser interferometer.  
     
     
       50. The substrate processing apparatus of claim 31, wherein the substrate processing apparatus is a deposition apparatus or a plasma etching apparatus.  
     
     
       51. The substrate processing apparatus of claim 31, wherein the substrate processing apparatus is a capacitively coupled plasma processing apparatus.  
     
     
       52. The substrate processing apparatus of claim 31 wherein each of the tubular support arms is configured to engage via a mounting arrangement with the respective actuation mechanism and wherein each mounting arrangement includes a ball in contact with a different geometric shape.  
     
     
       53. A method of processing a substrate in a substrate processing apparatus, the method comprising: placing a substrate on a support surface of a substrate support inside a vacuum chamber; vertically moving the substrate support to achieve a predetermined gap height between an upper surface of the substrate and a lower surface of an upper showerhead assembly; measuring planarization between the upper surface of the substrate and the lower surface of the upper showerhead assembly to determine if a desired planarization between the upper surface of the substrate and the lower surface of the upper showerhead assembly exists; adjusting in-situ the planarization of the substrate relative to the lower surface of the upper showerhead assembly by raising or lowering one or more of three actuation mechanisms respectively coupled to three support arms of the substrate support by kinematic mounting arrangements to adjust tilt, pitch and elevation of the support surface; supplying a gas into the vacuum chamber from a gas supply; and processing the substrate.  
     
     
       54. The method of claim 53, further comprising energizing the gas into a plasma state and etching the substrate with the plasma.  
     
     
       55. The method of claim 53, further comprising adjusting in-situ the planarization of the substrate during processing.  
     
     
       56. The method of claim 53, wherein the in-situ planarization is measured by at least one sensor which measures gap height and planarization before processing or during processing.  
     
     
       57. The method of claim 53, wherein the three actuation mechanisms are located outside the vacuum chamber and the three support arms extend through expandable vacuum seals, the planarization being effected by moving the support arms while maintaining a desired vacuum pressure inside the vacuum chamber.  
     
     
       58. The method of claim 53, further comprising reducing a pressure in the vacuum chamber to below 500 mTorr before processing the substrate and adjusting the planarization of the substrate prior to processing the substrate after the pressure in the vacuum chamber has been reduced to below 500 mTorr.  
     
     
       59. The method of claim 53, wherein the processing is a deposition process.  
     
     
       60. The method of claim 53, wherein the measuring comprises providing signals to a control system from at least one laser interferometer to effect real time measurements of gap height and planarization between the lower surface of the upper showerhead assembly and the upper surface of the substrate and/or the upper surface of the substrate support.  
     
     
       61. The method of claim 60, further comprising controlling the respective actuation mechanisms with the control system to adjust in-situ, gap height and planarization between the lower surface of the upper showerhead assembly and the upper surface of the substrate to effectuate uniform processing of the substrate based on the measurements taken by the at least one laser interferometer.  
     
     
       62. The method of claim 53, further comprising controlling the respective actuation mechanisms with a control system to adjust in-situ, gap height and planarization between the lower surface of the upper showerhead assembly and the upper surface of the substrate.  
     
     
       63. A substrate support of a substrate processing apparatus comprising: a substrate support configured to support a substrate on an upper surface thereof; and three tubular support arms attached to the substrate support, each of the tubular support arms configured to engage with a respective actuation mechanism operable to effect gap height and planarization adjustment of the substrate support, wherein the three tubular support arms each include a first section extending radially outward from an outer periphery of the substrate support and a second section extending vertically from the first section.  
     
     
       64. A substrate support of a substrate processing apparatus comprising: a substrate support configured to support a substrate on an upper surface thereof; and three tubular support arms attached to the substrate support, each of the tubular support arms configured to engage with a respective actuation mechanism operable to effect gap height and planarization adjustment of the substrate support, wherein the substrate support has a plenum and three radially extending bores extending between the plenum and an outer periphery of the substrate support wherein each of the tubular support arms defines a passage that is in communication with a respective bore.  
     
     
       65. A substrate processing apparatus comprising: a vacuum chamber; a substrate support in an interior of the vacuum chamber wherein the substrate support is configured to support a substrate on an upper surface thereof and three tubular support arms attached to the substrate support; an upper showerhead assembly supported by a top wall of the vacuum chamber; three openings in an outer wall of the vacuum chamber in which sections of the tubular support arms are located; three actuation mechanisms on the outer wall wherein each actuation mechanism is connected to a respective tubular support arm, the three actuation mechanisms operable to independently move the respective tubular support arms in upward and downward directions; at least one vacuum port in a bottom wall connected to at least one vacuum pump operable to maintain the vacuum chamber at a predetermined vacuum pressure; and a gas source operable to supply process gas through the upper showerhead assembly to the vacuum chamber, wherein an expandable vacuum seal seals each opening in the outer wall and maintains a vacuum tight seal between an outer periphery of each tubular support arm and the outer wall such that each tubular support arm may be moved by the respective actuation mechanism without exposing the interior of the vacuum chamber to atmospheric pressure.  
     
     
       66. A substrate processing apparatus comprising: a vacuum chamber; a substrate support in an interior of the vacuum chamber wherein the substrate support is configured to support a substrate on an upper surface thereof and three tubular support arms attached to the substrate support; an upper showerhead assembly supported by a top wall of the vacuum chamber; three openings in an outer wall of the vacuum chamber in which sections of the tubular support arms are located; three actuation mechanisms on the outer wall wherein each actuation mechanism is connected to a respective tubular support arm, the three actuation mechanisms operable to independently move the respective tubular support arms in upward and downward directions; at least one vacuum port in a bottom wall connected to at least one vacuum pump operable to maintain the vacuum chamber at a predetermined vacuum pressure; and a gas source operable to supply process gas through the upper showerhead assembly to the vacuum chamber, wherein the three actuation mechanisms are located on a top surface of the top wall of the vacuum chamber.  
     
     
       67. A substrate processing apparatus comprising: a vacuum chamber; a substrate support in an interior of the vacuum chamber wherein the substrate support is configured to support a substrate on an upper surface thereof and three tubular support arms attached to the substrate support; an upper showerhead assembly supported by a top wall of the vacuum chamber; three openings in an outer wall of the vacuum chamber in which sections of the tubular support arms are located; three actuation mechanisms on the outer wall wherein each actuation mechanism is connected to a respective tubular support arm, the three actuation mechanisms operable to independently move the respective tubular support arms in upward and downward directions; at least one vacuum port in a bottom wall connected to at least one vacuum pump operable to maintain the vacuum chamber at a predetermined vacuum pressure; and a gas source operable to supply process gas through the upper showerhead assembly to the vacuum chamber, wherein one or more of the tubular support arms includes one or more service conduits extending therethrough, the service conduits supplying at least one of a heat transfer gas, temperature controlled liquid coolant, RF energy, pressurized air, electrical monitoring signals or electrical actuating signals to or from the substrate support.  
     
     
       68. A substrate processing apparatus comprising: a vacuum chamber; a substrate support in an interior of the vacuum chamber wherein the substrate support is configured to support a substrate on an upper surface thereof and three tubular support arms attached to the substrate support; an upper showerhead assembly supported by a top wall of the vacuum chamber; three openings in an outer wall of the vacuum chamber in which sections of the tubular support arms are located; three actuation mechanisms on the outer wall wherein each actuation mechanism is connected to a respective tubular support arm, the three actuation mechanisms operable to independently move the respective tubular support arms in upward and downward directions; at least one vacuum port in a bottom wall connected to at least one vacuum pump operable to maintain the vacuum chamber at a predetermined vacuum pressure; a gas source operable to supply process gas through the upper showerhead assembly to the vacuum chamber; and a lower electrode assembly incorporated in the substrate support wherein the lower electrode assembly includes a lower electrode, wherein the lower electrode is coupled to a radio frequency (RF) power supply via an RF transmission member extending through one of the tubular support arms.  
     
     
       69. A substrate processing apparatus comprising: a vacuum chamber; a substrate support in an interior of the vacuum chamber wherein the substrate support is configured to support a substrate on an upper surface thereof and three tubular support arms attached to the substrate support; an upper showerhead assembly supported by a top wall of the vacuum chamber; three openings in an outer wall of the vacuum chamber in which sections of the tubular support arms are located; three actuation mechanisms on the outer wall wherein each actuation mechanism is connected to a respective tubular support arm, the three actuation mechanisms operable to independently move the respective tubular support arms in upward and downward directions; at least one vacuum port in a bottom wall connected to at least one vacuum pump operable to maintain the vacuum chamber at a predetermined vacuum pressure; and a gas source operable to supply process gas through the upper showerhead assembly to the vacuum chamber, wherein the upper showerhead assembly is an upper showerhead electrode assembly, including a C-shaped confinement ring positioned about a periphery of the upper showerhead electrode assembly and a lower electrode assembly incorporated in the substrate support within the vacuum chamber, the C-shaped confinement ring enclosing substantially all of an inter-electrode volume between the upper showerhead electrode assembly and the lower electrode assembly and comprising a plurality of openings, each of the openings extending substantially a length of an inter-electrode gap between a plasma exposed surface of the upper showerhead electrode assembly and the upper surface of the substrate support and facilitating gas exhaustion from the inter-electrode volume to the remaining volume of the vacuum chamber.  
     
     
       70. A substrate processing apparatus comprising: a vacuum chamber; a substrate support in an interior of the vacuum chamber wherein the substrate support is configured to support a substrate on an upper surface thereof and three tubular support arms attached to the substrate support; an upper showerhead assembly supported by a top wall of the vacuum chamber; three openings in an outer wall of the vacuum chamber in which sections of the tubular support arms are located; three actuation mechanisms on the outer wall wherein each actuation mechanism is connected to a respective tubular support arm, the three actuation mechanisms operable to independently move the respective tubular support arms in upward and downward directions; at least one vacuum port in a bottom wall connected to at least one vacuum pump operable to maintain the vacuum chamber at a predetermined vacuum pressure; and a gas source operable to supply process gas through the upper showerhead assembly to the vacuum chamber, wherein the vacuum chamber includes a cylindrical inner wall with three vertical channels extending into the cylindrical inner wall, the tubular support arms located in and movable in the vertical channels.  
     
     
       71. A substrate processing apparatus comprising: a vacuum chamber; a substrate support in an interior of the vacuum chamber wherein the substrate support is configured to support a substrate on an upper surface thereof and three tubular support arms attached to the substrate support; an upper showerhead assembly supported by a top wall of the vacuum chamber; three openings in an outer wall of the vacuum chamber in which sections of the tubular support arms are located; three actuation mechanisms on the outer wall wherein each actuation mechanism is connected to a respective tubular support arm, the three actuation mechanisms operable to independently move the respective tubular support arms in upward and downward directions; at least one vacuum port in a bottom wall connected to at least one vacuum pump operable to maintain the vacuum chamber at a predetermined vacuum pressure; a gas source operable to supply process gas through the upper showerhead assembly to the vacuum chamber; a control system in electrical communication with said actuation mechanisms operable to control gap height between a lower surface of the upper showerhead assembly and the upper surface of the substrate support and planarization of the upper surface of the substrate support and at least one laser interferometer, the at least one laser interferometer providing signals to the control system to effect real time measurements of the gap height between the lower surface of the upper showerhead assembly and the upper surface of the substrate support and the planarization of the upper surface of the substrate support.