JPH0874058A - Reaction furnace provided with isothermal rapid cooling means - Google Patents

Abstract

PURPOSE: To provide a highly productive reaction furnace with the temp. difference in the vertical direction reduced, capable of various homogeneous heat treatments with a uniform heat history and capable of rapid isothermal cooling in the thin film producing device, impurity diffusion furnace, thermal oxidation furnace and various reaction tubes used in etching, etc. CONSTITUTION: This reaction furnace is provided with an isothermal rapid cooling means formed by furnishing the annular cooling gas injection pipe 14 having many cooling gas injection ports 16 at an optional position on the periphery of a reaction tube 1 at least in one stage close to the peripheral surface of the reaction tube 1. Consequently, the difference in heat history between the materials to be heated such as wafers is reduced, the device characteristic is made uniform, the product yield is increased, the time required for the semiconductor producing process is shortened, and productivity is significantly improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to various thin film manufacturing apparatuses used in semiconductor manufacturing processes, impurity diffusion furnaces, thermal oxidation furnaces,
Or related to the reaction furnace used for etching equipment,
In particular, it relates to a reactor equipped with an isothermal rapid cooling mechanism.

[0002]

2. Description of the Related Art FIG. 7 shows an example of a conventional reactor equipped with conventional cooling means. This is an oxidation reactor used to produce a thermal oxide film on the surface of the wafer. In the figure, after mounting the wafer 8 on the boat 7 and treating it in the reaction tube 1 under a predetermined oxidizing atmosphere and temperature condition, the outer peripheral portion of the reaction tube 1 is heated from the vent hole 9 provided in the upper portion of the heater 2. The hot atmosphere in the furnace is sucked by the cooling blower 4 through the radiator 3 and discharged to the outside. An outside air inlet 10 is provided in the lower part of the heating furnace so that cold outside air flows to the outer peripheral portion of the reaction tube 1. In a conventional reaction furnace equipped with a cooling means, in order to increase the temperature lowering rate in the furnace, an external air introduction port provided in the lower part of the reaction tube 1 is provided by a cooling blower 4 provided in the downstream of the ventilation hole 9. Since the outside air 11 for cooling is drawn from the wafer 10, the wafer 8
At the time of cooling the inside of the furnace, a temperature difference occurs in the longitudinal sectional direction in the furnace, and a temperature difference (such as that shown in FIG. 5B) is generated between the upper wafer and the lower wafer filled in the reaction tube 1. 10
0 ° C. or higher), or as shown in FIG. 6 (b),
There is a temperature gradient on the surface of the wafer that is biased toward the exhaust direction of the outside air for cooling, the wafer cannot be isothermally cooled, and a uniform thermal oxide film cannot be formed on the wafer or impurities cannot be uniformly diffused. was there. Further, as shown in FIG. 4, in the conventional case, there is a problem that the cooling rate of the reaction tube 1 is slow, the processing efficiency such as the heat treatment of the wafer is extremely low, and the productivity is poor.

[0003]

As described above, in the prior art, in the cooling process of various heating reaction tubes used in the semiconductor manufacturing process, a temperature difference occurs in the longitudinal cross-sectional direction of the reaction tube, which causes the object to be heated. However, there is a problem that a thermal history difference occurs between wafers and the like, and it is not possible to form a thermal oxide film with a uniform film thickness and film quality. In addition, even thermal diffusion of impurities into the semiconductor, or homogeneous reaction Is not possible, and the isothermal cooling rate of the reaction tube is slow,
There was a problem that productivity was extremely poor.

The object of the present invention is to solve the above-mentioned problems in the prior art, and in various reaction tubes used in a thin film manufacturing apparatus, an impurity diffusion furnace, a thermal oxidation furnace, etching, etc. used in a semiconductor manufacturing process, A reactor equipped with an isothermal rapid cooling means with high productivity that can perform various homogeneous treatments with a uniform thermal history and has a small temperature difference in the longitudinal cross-sectional direction of To do.

[0005]

In order to achieve the above-mentioned object of the present invention, the constitution described in the claims is adopted. That is, as described in claim 1, a large number of cooling gas ejection ports are provided as isothermal rapid cooling means at arbitrary positions on the outer peripheral portion of various reaction tubes used for manufacturing a semiconductor device, for example, an annular cooling. The gas jet tube,
A reaction furnace having a structure in which at least one or more stages of reaction tubes are arranged in close contact with the outer peripheral surface of the reaction tube and is housed in a heating furnace. Further, as described in claim 2, the reaction tube according to claim 1 and the heating furnace for heating the reaction tube are provided, and the furnace atmosphere at the outer peripheral portion of the reaction tube is provided above the heating furnace. The reaction furnace is provided with an isothermal rapid cooling means having a structure in which at least one ventilation hole for absorbing the air and discharging it to the outside of the system is provided. Further, as described in claim 3, the shape of the annular cooling gas ejection pipe provided in the reaction tube according to claim 1 or 2 is an annular shape, an elliptical annular shape or a polygonal annular shape, and the cooling gas ejection tube is formed. The shape of the cooling gas ejection port provided in is a circular, oval, polygonal or slit-shaped nozzle.

[0006]

The reactor equipped with the isothermal rapid cooling means of the present invention,
As described in claim 1, an annular cooling gas ejection pipe having a large number of cooling gas ejection ports is provided at an arbitrary position on an outer peripheral portion of a reaction pipe used for manufacturing a semiconductor device, and an outer peripheral surface of the reaction pipe is provided. Since the outer peripheral surface of the reaction tube is effectively cooled by the cooling gas because it is provided in at least one step in close contact with the section, so-called isothermal rapid cooling is performed in a state where the temperature difference between the upper and lower portions of the reaction tube is small. It will be possible. Further, as described in claim 2, a vent hole for sucking the furnace atmosphere of the outer peripheral portion of the reaction tube and discharging it to the upper part of the heating furnace for heating the reaction tube according to claim 1. By providing
The high temperature atmosphere in the furnace is discharged to the outside of the furnace, and the isothermal rapid cooling is synergistically promoted by the cooling gas jetted from the outer peripheral surface of the reaction tube. Then, as described in claim 3, the cooling gas ejection pipe provided in close contact with the reaction tube according to claim 1 or 2 is formed into a circular ring shape, an elliptical ring shape, or a polygonal ring shape. Even the reaction tube has a shape that can be in close contact with the outer peripheral surface thereof, and the shape of the cooling gas ejection port is round, oval, polygonal or slit.
It is possible to set the shape of the cooling gas ejection port that is most effective for isothermal rapid cooling.

[0007]

Embodiments of the present invention will be described below in more detail with reference to the drawings. FIG. 1 shows an example of the overall structure of a reactor equipped with the isothermal rapid cooling means exemplified in this embodiment, FIG. 2 (a) shows an example of the structure of a cooling gas ejection pipe, and FIG. 2] is a schematic diagram showing a state in which the cooling gas ejection pipe of FIG. 2 (a) is set in a heating furnace. In the figure, a wafer 8 for forming a thermal oxide film is loaded inside the vertical reaction tube 1, and the reaction tube 1 is cooled after being heated in a predetermined atmosphere and temperature for a predetermined time. .
The atmosphere in the heating furnace at the outer peripheral portion of the reaction tube 1 is sucked and exhausted by the cooling blower 4. At this time, the cold outside air 11
It enters from the outside air introduction port 10, passes through the outer peripheral portion of the reaction tube 1, passes through the damper 5 through the vent hole 9 provided in the upper part of the heating furnace, is cooled by the radiator (heat exchanger) 3, and is a blower for cooling. It is discharged to the outside of the furnace by No. 4. On the other hand, cooling air is ejected from the cooling gas ejection port 16 of the cooling gas ejection pipe 14, which is provided in close contact with the outer peripheral portion of the reaction tube 1, and rises while cooling the outer peripheral surface of the reaction tube 1 to be heated. The gas is exhausted to the outside of the system through the ventilation hole 9 in the upper part of the furnace. By cooling the outer peripheral surface of the upper portion of the reaction tube 1 in this way, the temperature difference between the upper and lower wafers 8 loaded inside the reaction tube 1 becomes smaller, and as shown in FIG. The temperature difference in the isothermal cooling process of the lower wafer can be controlled to ± 5 ° C. or less. Further, as shown in FIG. 4, for example, in isothermal rapid cooling from 1000 ° C., the conventional cooling rate is about 2 ° C./min, and about 12 ° C. is needed to cool to 700 ° C.
Although it took 0 minutes, in the example of the present invention, the isothermal cooling rate was improved to about 5 ° C./minute, and the cooling time up to 700 ° C. was remarkably shortened to about 60 minutes. Then, the wafer 8 is loaded into the reaction tube 1, heated to a predetermined temperature, isothermally cooled, and one cycle required until the wafer 8 is taken out is about 200 minutes (cooling rate) in the conventional cooling method. However, according to the method of the present embodiment, it was possible to reduce the temperature to about 140 minutes (temperature decrease rate of 5 ° C./minute). Further, as a result of examining the temperature distribution difference on the wafer surface, in the conventional cooling method, as shown in FIG. 6B, the wafer temperature distribution difference is biased toward the cooling air exhaust direction, and the wafer temperature is about 20 ° C. In contrast to the temperature distribution difference, in the present embodiment, the temperature distribution difference is not biased with respect to the cooling gas discharge direction, the temperature is about 10 ° C. at the center of the wafer, and the wafer can be isothermally cooled substantially uniformly. did it. Further, as shown in FIG. 3, when the cooling gas jetting pipes are provided in two stages on the outer circumference of the reaction pipe 1, the upper wafer 8 and the lower wafer 8 are provided.
It was possible to improve the temperature difference between the temperature and the temperature from ± 5 ° C in the case of one stage to ± 2.5 ° C. In the above embodiments, the case where air is used as the cooling gas 13 has been described, but it goes without saying that an inert gas such as argon, nitrogen, carbon dioxide, etc. can be used. Further, although the cooling gas ejection pipe 14 has been described for one or two stages, it is also possible to provide three or more stages if necessary.

[0008]

As described in detail above, in the reactor equipped with the isothermal rapid cooling means of the present invention, at least one stage of the cooling gas ejection pipe having a simple structure is provided on the outer peripheral surface of the reaction pipe. Therefore, it is possible to effectively and rapidly cool the reaction tube isothermally, and it is possible to reduce the difference in the thermal history of the object to be heated such as a wafer, so that the device characteristics can be made uniform and the product yield can be further improved. it can. Further, since the cooling time of the object to be processed can be significantly shortened, the semiconductor manufacturing process time can be significantly shortened,
It is possible to further improve productivity.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing the configuration of a reactor equipped with an isothermal rapid cooling means exemplified in an embodiment of the present invention.

FIG. 2 is a schematic diagram showing a configuration of isothermal rapid cooling means exemplified in the embodiment of the present invention and a state of being mounted in a heating furnace.

FIG. 3 shows two cooling gas ejection pipes exemplified in the embodiment of the present invention.
The perspective view which shows the structure of the reaction tube provided in the step.

FIG. 4 is a graph showing the relationship between the temperature in the reaction tube and the cooling time illustrated in the examples of the present invention in comparison with the conventional one.

FIG. 5 is a graph showing the relationship between the temperature of the wafer in the reaction tube and the cooling time, which are exemplified in the example of the present invention, in comparison with the related art.

FIG. 6 is a schematic diagram showing the temperature distribution difference of the wafer illustrated in the embodiment of the present invention as compared with the conventional one.

FIG. 7 is a schematic diagram showing a configuration of a reaction furnace equipped with a conventional cooling means.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Reaction tube 2 ... Heater 3 ... Radiator 4 ... Cooling blower 5 ... Damper 6 ... Cap 7 ... Boat 8 ... Wafer 9 ... Vent hole 10 ... Outside air inlet 11 ... Outside air 12 ... Cooling gas inlet 13 ... Cooling gas 14 … Cooling gas jet pipe 15… Isotherm 16… Cooling gas jet

Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location H01L 21/306 21/31 E

Claims (3)

[Claims] 1. A ring-shaped cooling gas ejection pipe having a large number of cooling gas ejection ports provided at any position on the outer periphery of the reaction tube in close contact with at least one stage of the outer peripheral surface of the reaction tube. A reactor equipped with an isothermal rapid cooling means characterized in that the reactor is arranged as follows. 2. The reaction tube according to claim 1 and a heating furnace for heating the reaction tube, wherein the furnace atmosphere at the outer peripheral portion of the reaction tube is sucked into the upper part of the heating furnace to remove the outside of the system. A reactor equipped with an isothermal rapid cooling means, characterized in that at least one or more vent holes are provided for discharging into the chamber. 3. The shape of the annular cooling gas ejection pipe provided in close contact with the outer peripheral surface portion of the reaction tube according to claim 1 or 2 is a circular ring shape, an elliptical ring shape or a polygonal ring shape, A reactor equipped with an isothermal rapid cooling means, characterized in that the shape of the cooling gas ejection port provided in the ejection pipe is circular, oval, polygonal or slit.