Process gas flow guides for large area plasma enhanced chemical vapor deposition systems and methods

Abstract

The present invention provides methods and apparatus for a gas diffusion assembly in a deposition processing chamber. The invention includes a backing plate having an inlet for providing a process gas to a process chamber, a diffusion plate including a plurality of apertures for allowing the process gas to flow into the process chamber, a blocking plate disposed between the backing plate and the diffusion plate and including a plurality of apertures, and at least one gas flow guide disposed between the blocking plate and the backing plate and adapted to direct process gas flow laterally. Numerous additional features are disclosed.

The invention claimed is: 
     
         1 . A gas diffusion assembly comprising:
 a backing plate having an inlet for providing a process gas to a process chamber;   a diffusion plate including a plurality of apertures for allowing the process gas to flow into the process chamber;   a blocking plate disposed between the backing plate and the diffusion plate and including a plurality of apertures; and   at least one gas flow guide disposed between the blocking plate and the backing plate and adapted to direct process gas flow laterally.   
     
     
         2 . The gas diffusion assembly of  claim 1  wherein the at least one gas flow guide is adapted to direct process gas flow laterally toward an area above a substrate that would otherwise receive a lower deposition rate. 
     
     
         3 . The gas diffusion assembly of  claim 1  wherein the at least one gas flow guide is adapted to direct process gas flow laterally away from an area above a substrate that would otherwise receive a higher deposition rate. 
     
     
         4 . The gas diffusion assembly of  claim 1  wherein the at least one gas flow guide includes four inner gas flow guides disposed around the inlet. 
     
     
         5 . The gas diffusion assembly of  claim 4  wherein the inner gas flow guides are adapted to direct SiOx process gas laterally toward an area above a long edge of a substrate. 
     
     
         6 . The gas diffusion assembly of  claim 4  wherein the inner gas flow guides are adapted to direct SiOx process gas laterally away from an area above a corner of a substrate. 
     
     
         7 . The gas diffusion assembly of  claim 1  wherein the at least one gas flow guide is adapted to restrict lateral process gas flow from an area above a substrate that would otherwise receive a higher deposition rate. 
     
     
         8 . The gas diffusion assembly of  claim 1  wherein the at least one gas flow guide includes four outer gas flow guides disposed around the inlet. 
     
     
         9 . The gas diffusion assembly of  claim 8  wherein the four outer gas flow guides are adapted to restrict lateral flow of SiOx process gas from an area above center-crossing diagonal lines on a substrate. 
     
     
         10 . A low-temperature polysilicon processing chamber system comprising:
 a process gas supply;   a susceptor for supporting a substrate; and   a gas diffusion assembly including:
 a backing plate having an inlet coupled to the process gas supply; 
 a diffusion plate including a plurality of apertures for allowing the process gas to flow to the substrate; 
 a blocking plate disposed between the backing plate and the diffusion plate and including a plurality of apertures; and 
 at least one gas flow guide disposed between the blocking plate and the backing plate and adapted to direct process gas flow laterally. 
   
     
     
         11 . The low-temperature polysilicon processing chamber system of  claim 10  wherein the at least one gas flow guide is adapted to direct process gas flow laterally toward an area above the substrate that would otherwise receive a lower deposition rate. 
     
     
         12 . The low-temperature polysilicon processing chamber system of  claim 10  wherein the at least one gas flow guide is adapted to direct process gas flow laterally away from an area above the substrate that would otherwise receive a higher deposition rate. 
     
     
         13 . The low-temperature polysilicon processing chamber system of  claim 10  wherein the at least one gas flow guide includes four inner gas flow guides disposed around the inlet. 
     
     
         14 . The low-temperature polysilicon processing chamber system of  claim 13  wherein the inner gas flow guides are adapted to direct SiOx process gas laterally toward an area above a long edge of a substrate. 
     
     
         15 . The low-temperature polysilicon processing chamber system of  claim 13  wherein the inner gas flow guides are adapted to direct SiOx process gas laterally away from an area above a corner of the substrate. 
     
     
         16 . The low-temperature polysilicon processing chamber system of  claim 10  wherein the at least one gas flow guide is adapted to restrict lateral process gas flow from an area above the substrate that would otherwise receive a higher deposition rate. 
     
     
         17 . The low-temperature polysilicon processing chamber system of  claim 10  wherein the at least one gas flow guide includes four outer gas flow guides disposed around the inlet. 
     
     
         18 . The low-temperature polysilicon processing chamber system of  claim 17  wherein the four outer gas flow guides are adapted to restrict lateral flow of SiOx process gas from an area above center-crossing diagonal lines on the substrate. 
     
     
         19 . A method of flowing process gas into a processing chamber, the method comprising:
 determining an area on a substrate that will otherwise receive a relatively low deposition rate; and   directing process gas to flow laterally between a backing plate and a diffusion plate to an area above the substrate that will otherwise receive a relatively low deposition rate on the substrate.   
     
     
         20 . The method of  claim 19  further comprising:
 determining an area on a substrate that will otherwise receive a relatively high deposition rate; and 
 directing process gas to flow laterally between the backing plate and the diffusion plate away from an area above the substrate that will otherwise receive a relatively high deposition rate on the substrate.