Methods For Producing Quartz Parts With Low Defect And Impurity Densities For Use In Semiconductor Processing

Abstract

Described are methods and chemistries for preparing firepolished quartz parts for use in semiconductor processing. The quartz parts in need of preparation include newly manufactured parts as well as parts requiring refurbishment after previous use in semiconductor processing. The embodiments described avoid methods and chemistries that may damage the surfaces of the quartz parts and render the parts unfit for use in semiconductor processing. A method in accordance with one embodiment minimizes damage by limiting exposure of the quartz parts to hydrofluoric acid. A quartz part for use in semiconductor processing comprises a surface including a surface portion having a surface portion area to expose to a gas, wherein at least 95 percent of the surface portion area is free of defects and wherein the surface portion has less than E12 atoms per centimeter squared of aluminum.

1 . A method of protecting a quartz part from damage that would render the quartz part unsuitable for use in semiconductor processing, the quartz part having a surface portion to expose to a plasma during the semiconductor processing, the method comprising:
 firepolishing the surface portion of the quartz part;   processing the surface portion of the quartz part to remove contaminants; and   preventing exposure of the surface portion of the quartz part to hydrofluoric acid during a critical period, wherein the preventing comprises limiting a hydrofluoric acid concentration for a solution that contacts the surface portion to less than about 1 percent hydrofluoric acid;   wherein the critical period begins at the firepolishing and extends until a time when the quartz part is used in the semiconductor processing.   
   
   
       2 . The method of  claim 1 , wherein the processing comprises treating the quartz part with a nitric-acid solution to expose the surface portion to nitric acid. 
   
   
       3 . The method of  claim 2 , wherein the nitric-acid solution includes between about 10 and 70 percent nitric acid. 
   
   
       4 . The method of  claim 2 , wherein the nitric-acid solution has a nitric acid concentration and a ratio of the nitric acid concentration to the hydrofluoric acid concentration is greater than 50. 
   
   
       5 . The method of  claim 2 , wherein the surface portion of the quartz part had been exposed to a plasma in a plasma etching process prior to the firepolishing. 
   
   
       6 . The method of  claim 2 , wherein the quartz part had been used in semiconductor processing prior to the firepolishing. 
   
   
       7 . The method of  claim 2 , further comprising cleaning the surface portion of the quartz part with a hydrocarbon solvent to remove hydrocarbon-bearing contamination prior to the processing. 
   
   
       8 . The method of  claim 1 , further comprising precleaning the surface portion of the quartz part prior to the firepolishing. 
   
   
       9 . The method of  claim 1 , further comprising using the quartz part in semiconductor processing prior to the firepolishing. 
   
   
       10 . The method of  claim 1 , wherein the firepolishing is a step for firepolishing the quartz part. 
   
   
       11 . A quartz part produced in accordance with the method of  claim 2 . 
   
   
       12 . An apparatus for use in semiconductor processing, the apparatus comprising:
 a gas source; and   a quartz part comprising a surface, the surface including a surface portion to expose to the plasma, the surface portion having a surface portion area;   wherein at least 95 percent of the surface portion area is free of defects; and   wherein the surface portion has an average contamination concentration of less than E11 atoms per centimeter squared of aluminum.   
   
   
       13 . The apparatus of  claim 12 , wherein the quartz part is a refurbished quartz part. 
   
   
       14 . The apparatus of  claim 12 , wherein at least 99 percent of the surface portion area is free of defects.