Showerhead assembly with metrology port purge

Abstract

A method and apparatus that may be utilized for chemical vapor deposition and/or hydride vapor phase epitaxial (HVPE) deposition are provided. In one embodiment, the apparatus is a processing chamber that includes a showerhead with separate inlets and channels for delivering separate processing gases into a processing volume of the chamber without mixing the gases prior to entering the processing volume. In one embodiment, the showerhead includes metrology ports with purge gas assemblies configured and positioned to deliver a purge gas to prevent deposition thereon. In one embodiment, the metrology port is configured to receive a temperature measurement device, and the purge gas assembly is a concentric tube configuration configured to prevent deposition on components of the temperature measurement device. In one embodiment, the metrology port has a sensor window and is configured to receive an optical measurement device, and the purge gas assembly and sensor window are configured to prevent deposition on the sensor window.

1 . A showerhead assembly, comprising:
 a showerhead having:
 a first metrology port defining an interior region and extending through the showerhead; and 
 a second metrology port extending through the showerhead; 
   a first metrology assembly having an optical element that is at least partially disposed within the interior region of the first metrology port;   a first purge gas assembly having a first gas inlet coupled to a purge gas source and configured to direct a purge gas through the interior region of the first metrology port to prevent deposition of material on the optical element;   a second metrology assembly having a sensor window disposed adjacent the second metrology port; and   a second purge gas assembly having a gas inlet coupled to the purge gas source and configured to direct the purge gas toward the sensor window to prevent deposition of material thereon.   
     
     
         2 . The assembly of  claim 1 , wherein a sheath is concentrically disposed about the optical element and within the interior region. 
     
     
         3 . The assembly of  claim 2 , wherein the sheath has an aperture in fluid communication with the first gas inlet. 
     
     
         4 . The assembly of  claim 3 , wherein the first purge gas assembly has a second gas inlet fluidly coupled to the purge gas source and configured to direct the purge gas through the interior region of the first metrology port, wherein the first gas inlet is in fluid communication with a first portion of the interior region between the optical element and a first surface of the sheath, and wherein the second gas inlet is in fluid communication sheath. 
     
     
         5 . The assembly of  claim 1 , wherein the second purge gas assembly further comprises a gas distribution device having an annular channel in fluid communication with the gas inlet. 
     
     
         6 . The assembly of  claim 5 , wherein the gas distribution device is configured to direct the purge gas into a vortex adjacent the sensor window. 
     
     
         7 . The assembly of  claim 6 , wherein the gas distribution device has a plurality of passages fluidly connecting the annular channel with a central aperture formed through the gas distribution device. 
     
     
         8 . The assembly of  claim 1 , wherein the showerhead has:
 a first gas channel formed in the showerhead; and   a second gas channel formed in the showerhead and isolated from the first gas channel, wherein the first and second metrology ports extend through the first gas channel and the second gas channel.   
     
     
         9 . The assembly of  claim 8 , wherein the showerhead has a temperature control channel formed in the showerhead and isolated from the first and second gas channels, wherein the first and second metrology ports extend through the temperature control channel. 
     
     
         10 . The assembly of  claim 1 , wherein the first and second purge gas assemblies are each coupled to a cleaning gas source. 
     
     
         11 . The assembly of  claim 1 , wherein the sensor window has a cross-section in the shape of a wedge. 
     
     
         12 . The assembly of  claim 1 , wherein the sensor window is positioned at an angle between about 1 degree and about 4 degrees with respect to the gas inlet of the second purge gas assembly. 
     
     
         13 . A showerhead assembly, comprising:
 a showerhead having a metrology port defining an interior region and extending through the showerhead;   a metrology assembly having an optical element that is at least partially disposed within the interior region of the metrology port; and   a purge gas assembly having a first gas inlet coupled to a purge gas source and configured to direct a purge gas toward the optical element to prevent deposition of material thereon, wherein a sheath is concentrically disposed about the optical element and within the interior region, and wherein the sheath has an aperture in fluid communication with the first gas inlet.   
     
     
         14 . The assembly of  claim 13 , wherein the purge gas assembly has a second gas inlet fluidly coupled to the purge gas source and configured to direct the purge gas through the first metrology port. 
     
     
         15 . The assembly of  claim 13 , wherein the showerhead has:
 a first gas channel formed in the showerhead; and   a second gas channel formed in the showerhead and isolated from the first gas channel, wherein the metrology port extends through the first gas channel and the second gas channel.   
     
     
         16 . The assembly of  claim 15 , wherein the showerhead has a temperature control channel formed through the showerhead and isolated from the first and second gas channels, wherein the metrology port extends through the temperature control channel. 
     
     
         17 . A showerhead assembly, comprising:
 a showerhead having a metrology port extending through the showerhead;   a metrology assembly having a sensor window disposed adjacent the metrology port; and   a purge gas assembly having a gas inlet coupled to a purge gas source and a gas distribution device having an annular channel in fluid communication with the gas inlet, wherein the gas distribution device is configured to direct the purge gas into a vortex adjacent the sensor window.   
     
     
         18 . The assembly of  claim 17 , wherein the gas distribution device has a plurality of passages fluidly connecting the annular channel with a central aperture formed through the gas distribution device. 
     
     
         19 . The assembly of  claim 17 , wherein the showerhead has:
 a first gas channel formed in the showerhead; and   a second gas channel formed in the showerhead and isolated from the first gas channel, wherein the metrology port extends through the first and second gas channels.   
     
     
         20 . The assembly of  claim 19  wherein the showerhead has a temperature control channel formed in the showerhead and isolated from the first and second gas channels, wherein the metrology port extends through the first and second gas channels.