High temperature furnace insulation

Abstract

A high temperature furnace comprising hot zone insulation having at least one shaped thermocouple assembly port to reduce temperature measurement variability is disclosed. The shaped thermocouple assembly port has an opening in the insulation facing the hot zone that is larger than the opening on the furnace shell side of the insulation. A method for producing a crystalline ingot in a high temperature furnace utilizing insulation having a shaped thermocouple assembly port is also disclosed.

What is claimed is: 
     
         1 . A furnace comprising:
 a furnace shell;   a hot zone within the furnace shell, the hot zone comprising at least one heating element in the hot zone;   insulation surrounding the hot zone having a furnace shell side facing the furnace shell and a heating element side facing the heating element; and   at least one thermocouple assembly inserted through at least one thermocouple assembly port in the insulation, wherein the thermocouple assembly port increases in size from the furnace shell side of the insulation to the heating element side of the insulation.   
     
     
         2 . The furnace of  claim 1 , wherein the thermocouple assembly port comprises an opening on the heating element side of the insulation and an opening on the furnace shell side of the insulation, and wherein the opening on the heating element side of the insulation is larger than the opening on the furnace shell side of the insulation. 
     
     
         3 . The furnace of  claim 2 , wherein the thermocouple assembly port is countersunk on the heating element side of the insulation. 
     
     
         4 . The furnace of  claim 3 , wherein the thermocouple assembly port is countersunk at an angle of at least 60°. 
     
     
         5 . The furnace of  claim 3 , wherein the thermocouple assembly port is countersunk at an angle of at least 90°. 
     
     
         6 . The furnace of  claim 3 , wherein the thermocouple assembly port is countersunk at an angle of about 60° to about 120°. 
     
     
         7 . The furnace of  claim 3 , wherein the thermocouple assembly port is countersunk through at least one half of the insulation. 
     
     
         8 . The furnace of  claim 3 , wherein the thermocouple assembly port is countersunk through the insulation. 
     
     
         9 . The furnace of  claim 8 , wherein the insulation further comprises an insulation flange surrounding the opening on the furnace shell side of the insulation. 
     
     
         10 . The furnace of  claim 9 , wherein the insulation flange is at least about one-half as thick as the insulation. 
     
     
         11 . The furnace of  claim 2 , wherein the thermocouple assembly port is counterbored on the heating element side of the insulation. 
     
     
         12 . The furnace of  claim 11 , wherein the thermocouple assembly port is counterbored through at least one half of the insulation. 
     
     
         13 . The furnace of  claim 11 , wherein the thermocouple assembly port is counterbored at a diameter of at least twice the diameter of the thermocouple assembly port on the furnace shell side of the insulation. 
     
     
         14 . The furnace of  claim 2 , wherein the opening on the heating element side is circular, square or polygonal in shape. 
     
     
         15 . The furnace of  claim 1 , wherein the insulation comprises top and side insulation panels. 
     
     
         16 . The furnace of  claim 15 , wherein the side insulation panel is configured to move in a vertical direction relative to the crucible. 
     
     
         17 . The furnace of  claim 1  further comprising a heat exchanger in the hot zone for controlling heat extraction. 
     
     
         18 . The furnace of  claim 1 , further comprising a crucible in the hot zone on top of a crucible support block, the crucible configured to receive at least feedstock material. 
     
     
         19 . The furnace of  claim 18 , wherein the heating element heats and melts the feedstock material in the crucible to produce a crystalline ingot. 
     
     
         20 . The furnace of  claim 18 , wherein the feedstock material comprises polycrystalline silicon. 
     
     
         21 . The furnace of  claim 18 , wherein the feedstock material comprises aluminum oxide. 
     
     
         22 . The furnace of  claim 21 , wherein the aluminum oxide further comprises titanium. 
     
     
         23 . The furnace of  claim 19 , wherein the crystalline ingot comprises polycrystalline silicon. 
     
     
         24 . The furnace of  claim 19 , wherein the crystalline ingot comprises monocrystalline silicon. 
     
     
         25 . The furnace of  claim 19 , wherein the crystalline ingot comprises sapphire. 
     
     
         26 . Insulation surrounding a hot zone of a furnace, wherein:
 the insulation has a furnace shell side and a heating element side and comprises at least one thermocouple assembly port through the insulation to insert a thermocouple assembly and wherein the thermocouple assembly port is countersunk or counterbored on the heating element side of the insulation.   
     
     
         27 - 28 . (canceled)