Annealing apparatus and method of operating the same

Abstract

An annealing apparatus includes: a first chamber including a first gas having a first gas pressure; a second chamber configured to receive a second gas having a second gas pressure; gas inlets; gas vents; heating elements laterally surrounding the first chamber; and a controller configured to perform the steps of: heating the first chamber while keeping a gas pressure difference between the first gas pressure and the second gas pressure is within a tolerance limit; and cooling the first chamber by exchanging the second gas in the second chamber while keeping the gas pressure difference within the tolerance limit, wherein the exchanging of the second gas includes introducing the second gas to the second chamber through the plurality of gas inlets and exhausting a the second gas out of the second chamber through the plurality of gas vents while keeping the second gas pressure unchanged.

What is claimed is: 
     
         1 . An annealing apparatus, comprising:
 a first chamber configured to receive a wafer and including a first gas having a first gas pressure;   a second chamber surrounding the first chamber and configured to receive a second gas having a second gas pressure;   a plurality of gas inlets on a chamber wall of the second chamber;   a plurality of gas vents on the chamber wall of the second chamber;   a plurality of heating elements laterally surrounding the first chamber; and   a controller electrically coupled to the gas inlets, gas vents and heating elements, and configured to perform the steps of:
 heating the first chamber while keeping a gas pressure difference between the first gas pressure and the second gas pressure is within a tolerance limit; and 
 cooling the first chamber by exchanging the second gas in the second chamber while keeping the gas pressure difference within the tolerance limit, wherein the exchanging of the second gas includes introducing a first amount of the second gas to the second chamber through the plurality of gas inlets and exhausting a second amount of the second gas out of the second chamber through the plurality of gas vents while keeping the second gas pressure unchanged. 
   
     
     
         2 . The annealing apparatus according to  claim 1 , wherein the cooling of the first chamber while keeping the gas pressure difference within the tolerance limit comprises keeping the first gas pressure and the second gas pressure unchanged during the cooling. 
     
     
         3 . The annealing apparatus according to  claim 1 , wherein the plurality of gas inlets form pairs with the plurality of gas vents, wherein the cooling of the first chamber by exchanging the second gas further comprises causing different exchange amounts of the second gas for different pairs of the plurality of gas inlets and the plurality of gas vents during the cooling. 
     
     
         4 . The annealing apparatus according to  claim 1 , wherein the plurality of gas inlets or the plurality of gas vents are arranged at different heights of the chamber wall. 
     
     
         5 . The annealing apparatus according to  claim 1 , wherein the heating of the first chamber comprises activating the plurality of heating elements. 
     
     
         6 . The annealing apparatus according to  claim 5 , wherein the plurality of heating elements are arranged at different heights of the first chamber. 
     
     
         7 . The annealing apparatus according to  claim 6 , wherein the second chamber defines a plurality of zones corresponding to the plurality of heating elements, wherein the annealing apparatus further comprises temperature sensors configured to measure individual temperatures of the plurality of zones. 
     
     
         8 . The annealing apparatus according to  claim 7 , wherein the cooling of the first chamber comprises tuning each of the plurality of heating elements individually according to temperature measurements in the plurality of zones. 
     
     
         9 . The annealing apparatus according to  claim 7 , wherein the cooling of the first chamber comprises causing rates of temperature decreases in the plurality of zones are substantially equal during the cooling. 
     
     
         10 . The annealing apparatus according to  claim 1 , wherein the cooling of the first chamber comprises causing the first gas pressure and the second gas pressure to decrease with time while keeping the gas pressure difference within the tolerance limit. 
     
     
         11 . The annealing apparatus according to  claim 10 , wherein the first gas pressure and the second gas pressure are decreased in response to a temperature of the first chamber as being below a predetermined level during the cooling. 
     
     
         12 . The annealing apparatus according to  claim 1 , wherein the second gas comprises inert gas. 
     
     
         13 . An annealing apparatus comprising:
 a first chamber configured to receive a wafer and including a first gas having a first gas pressure;   a second chamber surrounding the first chamber and configured to receive a second gas having a second gas pressure;   a first gas inlet and a first gas vent on a chamber wall of the second chamber;   a second gas inlet and a second gas vent arranged on the chamber wall of the second chamber over the first gas inlet and the first gas vent;   a first heating element and a second heating element arranged in the second chamber; and   a controller electrically coupled to the first gas inlet, the first gas vent, the second gas inlet, the second gas vent, the firs heating element and the second heating element, and is configured to perform the steps of:
 heating the first chamber for a first period while keeping the second gas pressure substantially unchanged; and 
 after the first period, cooling the first chamber for a second period by performing exchange of the first gas in the second chamber through introducing a first amount of the second gas to the second chamber through the first and second gas inlets and exhausting a second amount of the second gas out of the second chamber while keeping the second gas pressure substantially unchanged. 
   
     
     
         14 . The annealing apparatus according to  claim 13 , wherein the controller further comprises, after the second period, cooling the first chamber for a third period while decreasing the first gas pressure. 
     
     
         15 . The annealing apparatus according to  claim 13 , wherein the performing of exchange of the second gas in the second chamber comprises causing different exchange amounts of the second gas for a first pair of the first gas inlet and the first gas vent and a second pair of the second gas inlet and the second gas vent during the second period. 
     
     
         16 . The annealing apparatus according to  claim 13 , wherein,
 the first gas inlet and the first gas vent are in a first zone of the second chamber,   the second gas inlet and the second gas vent are in a second zone of the second chamber, and   the cooling of the first chamber by introducing the second gas to the second chamber comprises causing the first zone and the second zone to have substantially equal rates of temperature decreases through controlling the first gas inlet, the first gas vent, the second gas inlet and the second gas vent individually.   
     
     
         17 . An annealing apparatus, comprising:
 a first chamber configured to receive a wafer and including a first gas having a first gas pressure; and   a second chamber surrounding the first chamber and configured to receive a second gas having a second gas pressure; and   a controller configured to perform the steps of
 during a first period, increasing the first and second gas pressures to predetermined pressures; 
 during a second period, heating the first chamber and keeping the first and second gas pressures at the respective predetermined pressures; 
 during a third period, cooling the first chamber by exchanging the second gas in the second chamber with an exterior environment while keeping a gas pressure difference between the first chamber and the second chamber within a tolerance limit, wherein the exchanging of the second gas includes introducing a first amount of the second gas to the second chamber and exhausting a second amount of the second gas out of the second chamber while keeping the second gas pressure unchanged; and 
 during a fourth period, cooling the first chamber and the second chamber by decreasing the first and second gas pressures while keeping the gas pressure difference within the tolerance limit. 
   
     
     
         18 . The annealing apparatus according to  claim 17 , further defining zones in a vertical direction of the annealing apparatus, wherein the controller is further configured to reduce temperature differences across the zones during the third period. 
     
     
         19 . The annealing apparatus according to  claim 17 , wherein during the first, second and third periods, the first gas pressure is less than the second gas pressure. 
     
     
         20 . The annealing apparatus according to  claim 19 , wherein the first gas pressure is less than the second gas pressure by less than about 2 atm.