Component of glass-like carbon for CVD apparatus and process for production thereof

Abstract

Disclosed herein is an inner tube of glass-like carbon for CVD apparatus and a process for production thereof. The inner tube has its surface roughened without increase in metal impurities which cause particles. It has improved adhesion to CVD deposit film and also has a high degree of roundness. The surface roughness (on both the inner and outer surfaces) is 0.1-10 μm measured according to JIS B0601. The concentration of metal impurities (iron, copper, chromium, sodium, potassium, calcium, magnesium, and aluminum) in the surface is less than 50×10 10 atoms/cm 2 .

What is clamed is:  
     
         1 . A component of glass-like carbon for CVD apparatus which is characterized by having a value of surface roughness (R a ) ranging from 0.1 to 10 μm (measured according to JIS B0601) and containing in its surface iron, copper, chromium, sodium, potassium, calcium, magnesium, and aluminum each in an amount less than 5×10 10  atoms/cm 2 .  
     
     
         2 . The component of glass-like carbon for CVD apparatus as defined in  claim 1 , which has a surface finished such that there exist at least five pits, 1-10 μm in diameter, in the visual field, 50×50 μm, observed under a scanning electron microscope with a magnification of ×1000.  
     
     
         3 . The component of glass-like carbon for CVD apparatus as defined in  claim 1 , which has a surface finished such that there exist elongated tiny depressions, 0.5-5 μm wide, whose total length is at least 50 μm, in the visual field, 50×50 μm, observed under a scanning electron microscope with a magnification of ×1000.  
     
     
         4 . The component of glass-like carbon for CVD apparatus as defined in  claim 1 , which is any of inner tube, wafer boat, susceptor, and nozzle used for CVD apparatus.  
     
     
         5 . A process for producing the component of glass-like carbon for CVD apparatus as defined in  claim 1 , comprising steps of: 
 molding an object from a raw material resin,    carbonizing the resulting molded object to give a molded object of glass-like carbon,    roughening the surface of the molded object, and    purifying the molded object of glass-like carbon.    
     
     
         6 . The production process as defined in  claim 5 , wherein roughening the surface of the molded object is performed after any step between the molding step and the carbonizing step.  
     
     
         7 . The production process as defined in  claim 5 , wherein purifying the molded object of glass-like carbon is performed at any step after the surface roughening treatment.  
     
     
         8 . The production process as defined in  claim 5 , wherein the surface roughening treatment is mechanical one.  
     
     
         9 . The process as defined in  claim 5 , wherein the surface roughening treatment is a combination of mechanical one and chemical etching one, which are performed sequentially (in the order mentioned) or simultaneously.  
     
     
         10 . The production process as defined in  claim 8 , wherein the mechanical surface roughening treatment is sandblasting or grinding.  
     
     
         11 . The production process as defined in  claim 9 , wherein the chemical etching treatment is thermal oxidation or electrolytic oxidation.  
     
     
         12 . The production process as defined in  claim 8 , wherein the component of glass-like carbon for CVD apparatus is an inner tube and the mechanical surface roughening treatment is performed on both the inner and outer surfaces of the inner tube all at once.  
     
     
         13 . The production process as defined in  claim 5 , wherein the purifying step is heat treatment at a high temperature in a halogen-containing gaseous atmosphere.  
     
     
         14 . A process for producing the component of glass-like carbon for CVD apparatus as defined in  claim 1 , with the component of glass-like carbon being an inner tube, said process comprising steps of molding a raw material resin into a tube, heating the resulting resin tube at 800-1300° C., thereby converting it into a glass-like carbon tube, and heating the glass-like carbon tube at a temperature higher than 1500° C., together with a roundness correcting jig attached to the outside of the glass-like carbon tube.