JPH06204156A - Vertical furnace - Google Patents

Abstract

PURPOSE:To improve quenching characteristics in the upper part of a reaction tube at the time of quenching, and make difference of temperature fall characteristics hardly occur between the upper part and the lower part of a furnace at the time of reducing the temperature, in the vertical type furnace of a semiconductor manufacturing equipment. CONSTITUTION:Spaces 16, 17 formed between a reaction tube and a heater surrounding the reaction tube are closed, and refrigerant introducing nozzles 14, 15 are inserted into the spaces. The tips of the refrigerant introducing nozzles are opened in the necessary positions of the upper parts of the spaces. An exhauster is connected with the lower part of the heater. The refrigerant is introduced from the refrigerant introducing nozzles and discharged through the exhauster. A vertical furnace is cooled while the refrigerant is made to descend.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vertical furnace of a semiconductor manufacturing apparatus for manufacturing a semiconductor element by producing a thin film and a diffusion process on the surface of a silicon wafer.

[0002]

2. Description of the Related Art A semiconductor manufacturing apparatus is equipped with a vertical furnace, a wafer is loaded into the vertical furnace, and a reaction gas is introduced into the furnace to form a thin film on a surface of a silicon wafer and perform a diffusion process. Then, there is one that manufactures a semiconductor device.

A conventional vertical furnace will be described with reference to FIG.

In the figure, reference numeral 1 is a reaction tube, which is inserted into a soaking tube 2 which is surrounded by a heater 3. A boat 4 is loaded into and unloaded from the reaction tube 1 by a boat elevator (not shown), and wafers 5 are held in a horizontal posture in multiple stages on the boat 4. Further, an exhaust device is connected to the heater 3, and the exhaust device is composed of an exhaust duct 6, a damper 7, a cooler 8 and a blower 9 provided on the exhaust duct 6 from the heater 3 side.

To process the wafer 5, the boat 4 loaded with the wafer 5 is loaded into the reaction tube 1, and the heater 3 is used.
The reaction gas is introduced from a reaction gas introduction port (not shown) in a heated state, and the required treatment is performed.

When the processing is completed, the furnace, the reaction tube and the like are rapidly cooled in order to prevent natural oxidation of the wafer 5 when the boat 4 is pulled out. The damper 7 is opened, the blower 9 is driven, and the air in the heater 3 is sucked. Air is sucked from the lower end of the heater 3, flows between the heater 3 and the heat equalizing pipe 2, cools the heater 3 and the heat equalizing pipe 2,
The heated air is cooled by the cooler 8 and exhausted through the blower 9.

After the heater 3 and the soaking tube 2 are cooled,
The boat 4 is pulled out, and the wafer 5 is removed from the boat 4.
Are transferred from the boat 4.

[0008]

In the above-mentioned conventional example, since the air flow flows into the heater 3 from the lower end of the heater 3, it begins to cool from the lower part of the furnace opening where the air near the room temperature first passes, and the lower part. However, there was a problem that the upper portion of the reaction tube 1, which had a large thermal effect from the above, did not cool easily. In addition, there is a problem that the film forming characteristics of wafers in the boat are affected if there is a large difference in the temperature lowering characteristics during quenching depending on the location of the boat.

In view of the above situation, the present invention is intended to improve the quenching characteristics in the upper portion of the reaction tube during quenching so that the temperature lowering characteristics are unlikely to be different between the upper and lower portions of the reaction tube when the temperature is lowered.

[0010]

According to the present invention, a space formed between a reaction tube and a heater surrounding the reaction tube is closed, and a cooling medium introducing nozzle is inserted into the space to introduce the cooling medium. The tip of the nozzle is opened at a required position above the space, and an exhaust device is connected to the bottom of the heater.

[0011]

The cooling medium introduced into the upper part cools the vertical furnace while descending in the space, and is exhausted by the exhaust device to effectively cool the upper part of the furnace where heat easily accumulates, eliminate the difference in temperature drop characteristics, and lower the temperature. Increase speed.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

It should be noted that, in FIG. 1, those having the same structure as those shown in FIG. 2 are denoted by the same reference numerals.

A flange 11a is provided at the lower end of the reaction tube 11, and the lower end of the soaking tube 12 is closed by the flange 11a.
A flange 12a is provided at the lower end of the soaking tube 12, and the lower end of the heater 13 is closed by the flange 12a.

A space 16 which penetrates the flange 11a of the reaction tube 11 and is formed by the reaction tube 11 and the soaking tube 12
The cooling nozzle 14 in the soaking tube is inserted into the above, and the upper end of the cooling nozzle 14 in the soaking tube is positioned at the upper end of the space 16.
Further, the cooling nozzle 15 in the heater is inserted into the space 17 formed by the soaking tube 12 and the heater 13 so as to penetrate the flange 12a of the soaking tube 12, and the upper end of the cooling nozzle 15 in the heater is set to the upper end of the space 17. Located in the section.

The cooling nozzle 14 in the soaking tube and the cooling nozzle 15 in the heater are connected to a nitrogen gas supply source (not shown), and the space is provided through the cooling nozzle 14 in the soaking tube and the cooling nozzle 15 in the heater. Nitrogen gas can be introduced into the space 16 and the space 17, and a flow rate regulator (not shown) is provided.

An exhaust port 18 is provided below the soaking tube 12, and the space 16 and the space 17 are provided through the exhaust port 18.
Communicate with. An exhaust duct 6 is provided below the heater 13, and a damper 7, a cooler 8 and a blower 9 are sequentially provided on the exhaust duct 6 from the heater 13 side.

When the processing of the wafer 5 is completed, nitrogen gas is introduced from the cooling nozzle 14 in the soaking tube and the cooling nozzle 15 in the heater, the damper 7 is opened, and the blower 9 is driven.

The nitrogen gas introduced by the cooling nozzle 14 in the soaking tube flows into the upper part of the space 16 and cools the atmosphere of the space 16 and the reaction tube 11 while descending in the space 16 and the exhaust port. The gas is exhausted from the exhaust duct 6 via 18. Further, the nitrogen gas introduced from the heater cooling nozzle 15 flows into the upper part of the space 17, and while descending the space 17, cools the atmosphere of the space 17 and the heater 13 and exhausts it from the exhaust duct 6. To be done.

The cooling medium is not limited to nitrogen gas.

According to this embodiment, since the lower end of the furnace opening is closed, the lowest cooling medium does not flow from the furnace opening to cool the lower part of the furnace opening, and the rapid cooling characteristic of the lower part of the furnace opening is achieved. Suppress. Furthermore, since the cooling medium is first introduced into the upper part, the tendency that heat is likely to be accumulated in the upper part is eliminated. or,
Since the cooling medium positively flows into the upper part and is sucked in the lower part, a flow of the cooling medium from the upper part to the lower part can be formed.

Further, in the present embodiment, the flow of the cooling medium is formed not only between the heater 13 and the soaking tube 12 but also between the reaction tube 11 and the soaking tube 12, so that the rapid cooling effect is further enhanced.

Further, since the flow rate of the cooling medium introduced can be adjusted by the above-mentioned flow rate controller, the cooling rate and the temperature lowering characteristic can be controlled together with the adjustment of the opening degree of the damper 7.

In the above embodiment, the cooling nozzle 1 in the soaking tube is used.
4, one heater cooling nozzle 15 in each space, but 2
It is also possible to provide more than one book and to make the installation place different or make the length different to improve the uniformity of the temperature lowering characteristics. Furthermore, in the above embodiment, the case where the soaking tube is provided has been described, but it goes without saying that the present invention can also be carried out in a vertical furnace without the soaking tube.

[0025]

As described above, according to the present invention, it is possible to reduce the temperature drop characteristic difference at the time of cooling the vertical furnace, so that more rapid cooling is possible, the process time is shortened, the yield of process wafers is improved, It is possible to shorten the heater down time during maintenance.

Further, by providing a plurality of cooling medium introducing nozzles, it is possible to further reduce the temperature drop characteristic difference and shorten the cooling time.

[Brief description of drawings]

FIG. 1 is a schematic sectional view showing an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view showing a conventional example.

[Explanation of symbols]

 6 Exhaust Duct 8 Cooler 9 Blower 11 Reaction Tube 11a Flange 12 Soaking Tube 12a Flange 13 Heater 14 Cooling Nozzle in Soaking Tube 15 Cooling Nozzle in Heater

Claims (2)

[Claims] 1. A space formed between a reaction tube and a heater surrounding the reaction tube is closed, a cooling medium introducing nozzle is inserted into the space, and a tip of the cooling medium introducing nozzle is placed above the space. A vertical furnace characterized in that an exhaust device is connected to a lower portion of the heater while being opened at a required position. 2. The vertical furnace according to claim 1, wherein a plurality of cooling medium introduction nozzles are provided, and at least one of the installation position and the length of the cooling medium introduction nozzle is different.