Purge and pumping structures arranged beneath substrate plane to reduce defects

Abstract

A substrate processing system includes a processing chamber including a top surface, a bottom surface and side walls. A substrate support is arranged in the processing chamber to support a substrate during processing. A purge structure is arranged in the processing chamber below a plane occupied by the substrate during processing. The purge structure includes a first plurality of holes configured to supply purge gas to purge an area between the substrate support and the bottom surface of the processing chamber.

What is claimed is: 
     
         1 . A substrate processing system comprising:
 a processing chamber including a top surface, a bottom surface and side walls;   a substrate support arranged in the processing chamber to support a substrate during processing; and   a purge structure arranged in the processing chamber below a plane occupied by the substrate during processing,   wherein the purge structure includes a first plurality of holes configured to supply purge gas to purge an area between the substrate support and the bottom surface of the processing chamber.   
     
     
         2 . The substrate processing system of  claim 1 , wherein the first plurality of holes directs purge gas in a downwardly direction towards the bottom surface of the processing chamber. 
     
     
         3 . The substrate processing system of  claim 1 , wherein the first plurality of holes directs purge gas in a downwardly and radially outwardly direction. 
     
     
         4 . The substrate processing system of  claim 1 , wherein the purge structure is connected to a bottom surface of the substrate support. 
     
     
         5 . The substrate processing system of  claim 1 , wherein the purge structure includes a body and a plenum defined in the body, wherein the first plurality of holes is formed in the body and is in fluid communication with the plenum. 
     
     
         6 . The substrate processing system of  claim 1 , wherein the purge structure includes a body and a cavity defined in the body, wherein the first plurality of holes is formed in the body and is in fluid communication with the cavity, and wherein the cavity and a bottom surface of the substrate support form a plenum. 
     
     
         7 . The substrate processing system of  claim 1 , wherein the purge structure includes an elongate member that is attached to a bottom surface of the substrate support. 
     
     
         8 . The substrate processing system of  claim 1 , wherein the substrate support includes a central supporting member connecting the substrate support to the bottom surface of the processing chamber and wherein the processing chamber further includes exhaust pumping ports. 
     
     
         9 . The substrate processing system of  claim 8 , further comprising a pumping structure arranged below the substrate support and around the central supporting member, wherein the pumping structure includes a second plurality of holes for controlling flow from the processing chamber through the pumping structure to the exhaust pumping ports. 
     
     
         10 . The substrate processing system of  claim 9 , wherein the pumping structure includes:
 a first portion arranged around the central supporting member; and   a second portion connected to the first portion and extending from the first portion to the side walls of the processing chamber, wherein the second plurality of holes of the pumping structure is arranged at spaced locations on the second portion.   
     
     
         11 . The substrate processing system of  claim 10 , wherein the first portion includes a cylindrical portion and the second portion includes a planar portion. 
     
     
         12 . The substrate processing system of  claim 11 , wherein the planar portion has a cross-section to mate with a bottom portion of the processing chamber and to define a first volume in fluid communication with a reaction zone and second volume in fluid communication with vacuum and wherein the first plurality of holes fluidly connects the first volume with the second volume. 
     
     
         13 . The substrate processing system of  claim 1 , further comprising a heater to heat the purge structure to a predetermined temperature. 
     
     
         14 . The substrate processing system of  claim 9 , further comprising a heater to heat the pumping structure to a predetermined temperature. 
     
     
         15 . A substrate processing system comprising:
 a processing chamber including a top surface, a bottom surface and side walls and exhaust pumping ports;   a substrate support arranged in the processing chamber to support a substrate during processing, wherein the substrate support includes a central supporting member connecting the substrate support to the bottom surface of the processing chamber; and   a pumping structure arranged in the processing chamber below the substrate support and around the central supporting member, wherein the pumping structure includes a first plurality of holes to control flow from the processing chamber through the pumping structure to the exhaust pumping ports.   
     
     
         16 . The substrate processing system of  claim 15 , wherein the pumping structure includes:
 a first portion arranged around the central supporting member; and   a second portion connected to the first portion and extending from the first portion to the side walls of the processing chamber, wherein the first plurality of holes of the pumping structure is arranged at spaced locations on the second portion.   
     
     
         17 . The substrate processing system of  claim 16 , wherein the first portion includes a cylindrical portion and the second portion includes a planar portion. 
     
     
         18 . The substrate processing system of  claim 15 , wherein the planar portion has a cross-section to mate with a bottom portion of the processing chamber and to define a first volume in fluid communication with a reaction zone and second volume in fluid communication with vacuum and wherein the first plurality of holes fluidly connect the first volume with the second volume. 
     
     
         19 . The substrate processing system of  claim 15 , further comprising a heater to heat the pumping structure to a predetermined temperature. 
     
     
         20 . The substrate processing system of  claim 15 , further comprising a purge structure arranged in the processing chamber below a plane defined by the substrate during processing, wherein the purge structure includes a plenum and a second plurality of holes configured to flow purge gas from the plenum through the second plurality of holes to purge an area between the substrate support and the bottom surface of the processing chamber.