JPH07326591A - Vertical furnace - Google Patents

Abstract

PURPOSE:To provide a l vertical furnace wherein isothermal quenching is possible by a simple structure of just adding a nozzle for introducing cooling gas, efficiency can be improved by reducing a cooling time and by reducing a process time, difference of thermal hysterisis of a wafer is reduced and yield can be thereby improved without changing conventional constitution. CONSTITUTION:A reaction tube 2 for heating and processing a wafer 4 is inserted into a chamber of a heater 1, an exhaust system 5 for cooling and discharging inside atmosphere is connected to the heater 1 chamber and a nozzle 9 for introducing cooling gas is inserted into the heater 1 chamber.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical furnace for heat-treating wafers such as film formation and oxidation.

[0002]

2. Description of the Related Art FIG. 3 is a schematic sectional view showing the structure of an example of a conventional vertical furnace, and FIG. 4 is an explanatory view showing the internal temperature distribution of a conventional heater. In FIG. 3, 1 is a heater, 1 A is a heat generating zone, 2 is a reaction tube inserted in the heater chamber, 3 is a boat on which a large number of wafers 4 are mounted, and the boat is carried into the reaction tube 2 and a large number of wafers are loaded. 4 is subjected to a heat treatment such as a film forming treatment by introducing a reaction gas and an oxidizing treatment. Reference numeral 5 denotes an exhaust system connected to a ventilation hole provided in the upper part of the heater 1 chamber, which cools the atmosphere in the heater chamber and exhausts it. The exhaust system 5 includes a damper 6, a radiator 7 and a cooling blower 8 provided in the exhaust furnace.
Consists of.

In such a conventional vertical furnace, after the wafer 4 is loaded into the reaction tube 2, the furnace opening side at the lower end is sealed and the wafer 4 is heat-treated. After that, when the wafer is unloaded, if the furnace opening side is opened, the cooled gas (air) flows from the furnace opening side into the heater chamber in the direction of the arrow to cool the atmosphere inside the heater chamber, and the gas used for cooling is Exhaust is performed by a cooling blower 8 through a damper 6 and a radiator 7 from a ventilation hole in the upper part of the heater chamber. By cooling the atmosphere in the heater chamber to cool the reaction tube 2 and sufficiently lower the temperature of the processed wafer inside, the processed wafer is unloaded from the reaction tube 2.

[0004]

In the above-mentioned conventional example, since the cooled gas is drawn from the furnace opening side A at the lower end when cooling the inside of the furnace at the time of carrying out the wafer, the gas is blown into the vent hole side B above the heater chamber. As shown in FIG. 4, when the temperature reaches the temperature, a temperature gradient becomes considerably high and a temperature gradient occurs, which causes a temperature difference in the furnace, and the thermal history of the wafer is different between the vent hole side and the furnace mouth side. There are challenges.

[0005]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has a simple structure in which a nozzle for introducing a cooling gas is simply added to the isothermal quenching without changing the conventional structure. Therefore, it is an object of the present invention to provide a vertical furnace in which the cooling time can be shortened, the process time can be shortened, the efficiency can be improved, the difference in the thermal history of wafers can be reduced, and the yield can be improved. That is, in the vertical furnace of the present invention, the reaction tube 2 for heat-treating the wafer 4 is inserted in the heater 1 chamber, the exhaust system 5 for cooling and exhausting the internal atmosphere is connected to the heater 1 chamber, and the heater 1 is also connected. It is characterized in that a nozzle 9 for introducing cooling gas is inserted into the room.

[0006]

With the above-described structure, by introducing the cooling gas from the nozzle 9 into the upper part of the heater 1 chamber, the temperature on the vent hole side B in the upper part of the heater chamber is lowered and the temperature gradient is reduced. The temperature distribution inside the chamber becomes uniform, and the thermal history of the wafer 4 inside the reaction tube 2 becomes substantially the same on the furnace port side A and the vent hole side B.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a simplified sectional view showing the construction of one embodiment of the vertical furnace of the present invention, and FIG. 2 is an explanatory view showing the internal temperature distribution of the heater in the present invention. In the present embodiment, the reaction tube 2 is inserted into the heater 1 chamber, the boat 3 on which a large number of wafers 4 are placed is inserted into the reaction tube 2, and the vent hole provided in the upper part of the heater 1 chamber is inserted. , The exhaust system 5 for cooling and exhausting the internal atmosphere is connected, and the nozzle 9 for introducing the cooling gas is inserted into the heater 1 chamber, and the nozzle 9 is connected with the flow rate controller 10 connected to the gas supply source. Excuse me.

In the present embodiment having the above-mentioned structure, after the boat 3 having a large number of wafers 4 mounted therein is carried into the reaction tube 2, the furnace opening at the lower end is closed and the wafers 4 are heat-treated. After that, when the furnace opening side is opened when the wafer is unloaded, the cooled gas (air) flows from the furnace opening side into the heater 1 chamber in the direction of the arrow while the cooling gas from the gas supply source flows in the flow controller 1.
The flow rate is adjusted by 0 and introduced into the upper part of the heater 1 chamber from the nozzle 9 to cool the atmosphere in the heater chamber,
The gas used for cooling passes through the ventilation hole in the upper part of the heater chamber, passes through the damper 6 and the radiator 7 of the exhaust system 5, and is exhausted by the cooling blower 8.

When the cooling gas is not introduced through the nozzle 9, the temperature of the gas (air) becomes considerably high by the time when the gas (air) reaches the vent hole side in the upper part of the heater chamber, and a temperature gradient occurs. 2 is introduced, the temperature of the vent hole side B in the upper part of the heater chamber is lowered by the cooling gas introduced from the nozzle 9 as shown in FIG. 2, the temperature gradient is reduced, and the temperature distribution in the heater chamber is made uniform. As a result, the thermal history of the wafer 4 inside the reaction tube 2 becomes substantially the same on the furnace port side A and the vent hole side B. The number of nozzles 9 may be one or plural, and fine cooling can be performed by inserting a plurality of nozzles at a required angle.

[0010]

As is apparent from the above description, according to the present invention, isothermal quenching can be performed without changing the conventional structure and with a simple structure in which a nozzle for introducing a cooling gas is added, and the cooling time is reduced. It is possible to shorten the process time, shorten the process time, improve the efficiency, reduce the difference in the thermal history of the wafers, and improve the yield.

[Brief description of drawings]

FIG. 1 is a simplified cross-sectional view showing the configuration of an example of a vertical furnace of the present invention.

FIG. 2 is an explanatory diagram showing an internal temperature distribution of a heater according to the present invention.

FIG. 3 is a simplified cross-sectional view showing the configuration of an example of a conventional vertical furnace.

FIG. 4 is an explanatory diagram showing an internal temperature distribution of a conventional heater.

[Explanation of symbols]

 1 Heater 1A Heat Generation Zone 2 Reaction Tube 3 Boat 4 Wafer 5 Exhaust System 6 Damper 7 Radiator 8 Cooling Blower 9 Nozzle 10 Flow Controller

Claims (1)

[Claims] 1. A reaction tube for heat-treating a wafer is inserted in the heater chamber, an exhaust system for cooling and exhausting the internal atmosphere is connected to the heater chamber, and a nozzle for introducing cooling gas is inserted into the heater chamber. A vertical furnace characterized by