Thermal treatment equipment

Abstract

Thermal treatment equipment for rapidly heating a SiC substrate having a diameter of several inches or larger to a temperature as high as 1200° C. or higher with a high in-plane evenness by heating a peripheral zone of a substrate using high frequency induction and by heating a central zone of the substrate using infrared lamps while the substrate and a stage thereof are covered with a shield plate.

1 . A thermal treatment equipment comprising: 
 a chamber for allowing thermal treatment to be carried out in vacuum or various gas atmospheres;    an electrically conductive sample stage positioned within said chamber for receiving a sample to be treated;    a high frequency coil surrounding said sample stage;    an infrared generator consisting of at least one infrared waveguide quartz column placed above or below said sample;    an infrared lamp and a rotary elliptical reflector placed on one end of said infrared waveguide quartz column;    a coaxial double-wall quartz tube placed inside said high frequency coil for receiving cooling water in said coaxial double-wall quartz tube; and    wherein said infrared lamp is water or air cooled by cooling water or air flowing outside said infrared lamp.    
   
   
       2 . The thermal treatment equipment as defined in  claim 1 , wherein a quartz plate is interposed between a sample and said infrared waveguide quartz column.  
   
   
       3 . The thermal treatment equipment as defined in any one of claims  1  or  2 , wherein a sample and said sample stage are covered with a shield plate.  
   
   
       4 . The thermal treatment equipment as defined in any one of claims  1  through  3 , wherein said sample stage is covered with an electrically conductive shield plate provided with a gap having a dimension in a range of from about 1 mm to about 30 mm.  
   
   
       5 . The thermal treatment equipment as defined in any one of claims  1  through  4 , wherein said sample stage is made of one of tungsten, molybdenum or tantalum.  
   
   
       6 . The thermal treatment equipment as defined in any one of claims  1  through  4 , wherein said shield plate is made of one of tungsten, molybdenum or tantalum.  
   
   
       7 . The thermal treatment equipment as defined in any one of claims  1  through  4 , wherein said sample stage is made of one of carbon or SiC coated carbon.  
   
   
       8 . The thermal treatment equipment as defined in any one of claims  1  through  4 , wherein said shield plate is made of one of carbon or SiC coated carbon.  
   
   
       9 . The thermal treatment equipment as defined in any one of claims  1  through  8 , wherein the high frequency wave has a frequency of less than about 50 kHz.  
   
   
       10 . The thermal treatment equipment as defined in any one of claims  1  through  9  and further comprising a mechanism adapted to adjust a distance between one end surface of said quartz column and a sample in a range of from about 0.5 mm to about 20 mm.  
   
   
       11 . The thermal treatment equipment as defined in any one of claims  1  through  10  and further comprising a sample temperature control means adapted to measure a temperature of one of the sample stage or a sample using one of a pyrometer or a thermocouple to thereby control the value of voltage or current applied to the infrared lamp or the high frequency coil.  
   
   
       12 . The thermal treatment equipment as defined in any one of claims  1  through  11 , wherein said quartz column is tilted.  
   
   
       13 . The thermal treatment equipment as defined in any one of claims  1  through  12 , wherein said equipment is programmed so that a SiC substrate is heated from a room temperature to about 1200° C. or higher in from about 10 seconds to about 5 minutes, then maintained at such temperature for about 10 seconds to about 10 minutes and thereafter the SiC substrate is cooled to a temperature lower than about 1200° C. in about 10 seconds to about 30 minutes.  
   
   
       14 . The thermal treatment equipment as defined in  claim 13 , wherein said equipment is programmed so that the SiC substrate is previously heated to a temperature lower than about 1200° C., then heated from a room temperature to about 1200° C. or higher in about 10 seconds to about 5 minutes and thereafter cooled to a temperature lower than about 1200° C. in about 10 seconds to about 30 minutes.  
   
   
       15 . Thermal treatment equipment comprising: 
 a chamber for allowing thermal treatment to be carried out in vacuum or various gas atmospheres;    an electrically conductive sample stage positioned within said chamber for receiving a sample to be treated;    a high frequency coil surrounding said sample stage;    an infrared generator consisting of at least one infrared waveguide quartz column positioned to direct infrared energy toward said sample; and    a temperature control circuit coupled to said coil and said infrared waveguide quartz column and programmed to heat a SiC substrate from a room temperature to about 1200° C. or higher in from about 10 seconds to about 5 minutes, then maintained at such temperature for about 10 seconds to about 10 minutes and thereafter the SiC substrate is cooled to a temperature lower than about 1200° C. in about 10 seconds to about 30 minutes.    
   
   
       16 . Thermal treatment equipment comprising: 
 a chamber for allowing thermal treatment to be carried out in vacuum or various gas atmospheres;    an electrically conductive sample stage positioned within said chamber for receiving a sample to be treated;    a high frequency coil surrounding said sample stage;    an infrared generator consisting of at least one infrared waveguide quartz column positioned to direct infrared energy toward said sample; and    a temperature control circuit coupled to said coil and said infrared waveguide quartz column and programmed so that said SiC substrate is previously heated to a temperature lower than about 1200° C., then heated from a room temperature to about 1200° C. or higher in about 10 seconds to about 5 minutes and thereafter cooled to a temperature lower than about 1200° C. in about 10 seconds to about 30 minutes.