JPH04101419A - Heat treatment furnace for substrate - Google Patents

Abstract

PURPOSE:To increase a maximum operating temperature up to a heat resistance temperature region of a cylindrical heat insulating material by disposing a cylindrical heat resisting material between a heater wire and an external cylinder in such a way that a gap is formed with at least the heater wire. CONSTITUTION:In a heating apparatus 4, a heater wire 8 is supported in space by using a group of bar-shaped support members 5 and a group of spacers 9, and a ring gap is formed between the heating apparatus 4 and an external cylinder 3. Then, a cylindrical heat resisting material 10 is disposed between the heater wire 8 and the external cylinder 3 in such a way that gaps Sa and Sb are formed between it and the heater wire 8, and the external cylinder 3, respectively.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention is applicable to, for example, oxidation furnaces, diffusion furnaces, CVD (chemical
It relates to heat treatment furnaces used to heat semiconductor substrates (hereinafter simply referred to as substrates), such as reaction furnaces for cal vapor deposition) layers, and in particular, heat treatment furnaces in which a plurality of rod-shaped The present invention relates to a heat treatment furnace in which a heater wire is supported in a hollow manner by a support member.

<Prior art> Conventionally, as this type of heat treatment furnace, for example, JP-A-63-
As disclosed in Japanese Patent Application Laid-open No. 278226 and Japanese Patent Application Laid-open No. 64-60988, a plurality of rod-shaped support members are arranged around the furnace core tube that houses the substrate in the tube axis direction, and the rod-shaped support members are arranged in the tube axis direction. The applicant has proposed a device in which a heater wire is supported in a hollow manner by a member, and an outer cylindrical body is disposed around the heater wire.

Heat treatment furnaces that support heater wires in a hollow manner have a higher heat capacity than previous heat treatment furnaces in which heater wires were supported buried in or in contact with the insulation material. Since it is small, it takes a short time to reach thermal equilibrium, has good flat ramping characteristics, and has excellent features such as easy forced air cooling.

<Problems to be Solved by the Invention> However, even in the conventional example having such a configuration, the following points to be improved have been found.

In other words, in the case of the above-mentioned heat treatment furnace with a heater wire hollow support structure, a heat reflective film such as a thin gold film is formed on the inner surface of the outer cylinder that surrounds the heater wire supported in the air in order to increase heat utilization efficiency. However, the heat resistance of this type of heat-reflecting film is not sufficiently high, which limits the maximum operating temperature of the heat treatment furnace.
The degree was the upper limit.

SUMMARY OF THE INVENTION An object of the present invention is to solve these problems and provide a substrate heat treatment furnace that can increase the maximum operating temperature while effectively exhibiting the characteristics of the previously proposed heat treatment furnace.

<Means for solving the problem> In order to achieve the above object, the present invention adopts the following configuration.

That is, in the present invention, around the furnace core tube that houses the substrate,
A plurality of rod-shaped support members are arranged in the tube axis direction, and the heater wire is hollowly supported by the rod-shaped support members, and
In a substrate heat treatment furnace in which an outer cylinder is arranged around the heater wire, a cylindrical heat insulating material is arranged between the heater wire and the outer cylinder so that at least a gap is formed between the heater wire and the heater wire. This is what I did.

<Effect> The effects of the present invention are as follows.

That is, since there is a gap between the heater wire and the cylindrical heat insulating material surrounding it, the heat capacity is smaller than that in a case where the heater wire is supported in contact with the cylindrical heat insulating material. Since forced air cooling is easy to perform, it is possible to raise and lower the temperature at high speed.

Further, the temperature of the cylindrical heat insulating material increases as it receives radiant heat from the heater wire, so that the temperature uniformity in the axial direction of the cylindrical heat insulating material is good.

Moreover, if the heat-resistant temperature of the heater wire permits, the maximum operating temperature can be increased to the heat-resistant temperature of the heat insulating material (for example, 1600 to 1800'C).

<Example> Hereinafter, an example in which the present invention is applied to a vertical heat treatment furnace will be described in detail with reference to the drawings.

FIG. 1 is a longitudinal cross-sectional view of a vertical heat treatment furnace according to an embodiment, and FIG. 2 is a cross-sectional view thereof.

This heat treatment furnace includes a furnace core tube 1 made of quartz glass or ceramic that accommodates a substrate 2, an outer cylinder 3 made of stainless steel, for example, into which the furnace core tube 1 is inserted in a vertical position, and a furnace core tube 1.
A heating device 4 provided in the gap between the furnace core tube 1 and the heating device 4, a means for forcibly cooling the furnace core tube 1 and the heating device 4, and a means for supplying and discharging a reaction gas into the furnace core tube 1. There is.

The structure of the heating device 4 is as follows. A plurality of rod-shaped support members 5 made of, for example, hollow ceramic tubes are disposed outside the outer peripheral surface of the furnace core tube 1 along the tube axis direction.

These rod-shaped support members 5 are supported at their upper and lower ends by flanges 6.7 provided at the upper and lower openings of the outer cylinder 3, respectively. Each rod-shaped support member 5 is arranged around the furnace core tube 1, as shown in FIG. That is, there are a set of two rod-shaped support members arranged in parallel at small intervals, and a plurality of sets of these are arranged at equal intervals in the circumferential direction of the furnace core tube 1.

As shown in FIG. 3, a strip-shaped heater wire 8 that is spirally wound around the furnace core tube 1 is wound around each pair of rod-shaped support members 5 in an S-shape. The length between the rod-shaped support members of each set is also bent to have a long heat generation length.

In addition, in order to ensure the vertical arrangement pitch of the heater wires 8,
Ceramic noshes 9 are provided for each pair of rod-shaped support members 5.
is fitted externally.

As described above, the heating device 4 has a structure in which the heater wire 8 is supported in the air using five groups of rod-shaped support members and nine groups of spanners. Furthermore, by winding the heater wire 8 around the rod-shaped support member 5 in an S-shape as described above, even if the heater wire 8 expands due to heating, it can be prevented from falling off from the rod-shaped support member 5. However, the structure of the winding of the heater wire is not limited to the above-mentioned example, and can be arbitrarily modified.

The heater wire 8 and the outer cylinder 3 are inserted into the annular gap formed between the heating device 4 and the outer cylinder 3 configured in this way.
The cylindrical heat insulating material 1o is arranged so that gaps Sa and Sb are formed between the two.

In this embodiment, in order to further reduce the heat capacity, a gap sb is provided between the outer cylinder 3 and the cylindrical heat insulating material 10, but it is not necessary to provide the gap sb. and the cylindrical heat insulating material 10 may be placed in contact with each other.

The cylindrical heat insulating material 10 is: ■ fired ceramic fiber, ■ ceramic tube coated with ceramic fiber, ■ ceramic fiber fired in a thin wave shape, stacked in multiple layers to form a honeycomb structure. etc. are available. In particular, the cylindrical heat insulating material 10 having the structure described in Item 1 (2) in which a ceramic tube is disposed on the inner surface is preferable in that dust generation from the inner surface is suppressed even if cooling air flows along the inner surface. In addition, each cylindrical l in two rows! It is preferable to coat the inner surface of the heat material 10 with a heat reflective film made of ceramics to increase the heat utilization efficiency.

On the other hand, an intake chamber 11 having an intake hole 1a is provided at the lower end of the outer cylinder body 3, and an exhaust chamber 12 having an exhaust boat 12a is provided at one end of the outer cylinder body 3. Cooling air is introduced into the gap between the furnace core tube and the cylindrical heat insulating material 10 to forcibly cool the furnace core tube 1 and the heating device 4, and then is discharged from the exhaust port 1-12a.

Further, a cooling vibe 13 to which cooling water is supplied is wound and welded to the outer peripheral surface of the outer cylinder 3.

Furthermore, a manifold 1 takes out and discharges the reaction gas supplied into the tube from the upper end of the furnace core tube 1 from the lower end of the furnace core tube 1.
4 is removably installed at the bottom of the intake chamber 11,
The lower end of the furnace core tube 1 is supported by this manifold 14. An opening for inserting a wafer boat is formed in the lower part of the manifold 14, and the wafer boat insertion opening is closed by a flange 15 connected to the boat holder G during processing.

Next, a preferred embodiment of the gap Sa formed between the heating device 4 and the cylindrical heat insulating iJ' 10 will be described.

As shown in FIG. 4(a), a belt-shaped heater wire 8 with a width W is
The cylindrical heat insulating materials 10 are arranged in parallel at the same interval as this width W.
The distance between the inner surface of the heater wire 8 and the radiation intensity ratio A at a point P facing the heater wire 8 and a point P2 facing between the heater wires (A - radiation intensity at point PI/radiation at point P2) Figure 4 (b
).

As is clear from this characteristic diagram, the larger the distance t, the closer the radiation intensity ratio A becomes to 1, resulting in adiabatic insulation (radiation to A becomes uniform and the temperature distribution becomes uniform; however, on the other hand, As the diameter becomes larger, the device becomes larger.On the other hand, as the distance t becomes smaller, the ratio of the radiation intensity increases and the temperature distribution becomes uneven, but the device becomes smaller.

In this example, the temperature distribution of the cylindrical heat insulating material 8 is relatively uniform,
In addition, a suitable distance t that can suppress the increase in size of the device is the same distance to about three times the width W of the heater wire 8 (W≦t≦3w).

In addition, although the above-mentioned embodiment was explained by taking a joint type heat treatment furnace as an example, the present invention can also be applied to a horizontal type heat treatment furnace.

<Effects of the Invention> As described in 2 below, according to the present invention, the heater wire is supported in the air and an appropriate distance is formed between the heater wire and the inner surface of the cylindrical heat insulating material surrounding the heater wire. As long as the heat resistance of the heater wire allows, the maximum operating temperature can be raised to the surface temperature range of the cylindrical heat insulating material. In addition, the temperature of the cylindrical heat insulating material can be raised uniformly in the longitudinal direction of the furnace by radiant heat, and
Since the heat capacity of the heating device as a whole can be reduced, flat ramping characteristics in high temperature ranges can also be improved.

[Brief explanation of drawings]

Figures 1 to 4 show an embodiment of the present invention, with Figure 1 being a vertical cross-sectional view of a vertical heat treatment furnace, Figure 2 being a cross-sectional view thereof, and Figure 3 being a part of a heating device. Perspective view, Figure 4(a)(b)
) is an explanatory diagram showing the radiation heating characteristics of a heat insulating material. 1... Furnace core tube 3... Outer cylinder body 4... Heating device 5... Rod-shaped long member 8... Heater wire
9... Spacer 10... Cylindrical I insulation material Sa, S
b... Gap Applicant Dainippon Screen Mfg. Co., Ltd. Agent Patent Attorney Tsutomu Sugitani Figure Figure Figure Figure (a) Radiation intensity at point P2

Claims (1)

[Claims] (1) A plurality of rod-shaped support members are arranged around the furnace core tube that houses the substrate in the tube axis direction, and the heater wire is supported hollowly by the rod-shaped support member, and the heater wire is A substrate heat treatment furnace provided with a cylindrical body, characterized in that a cylindrical heat insulating material is disposed between the heater wire and the outer cylindrical body so that at least a gap is formed between the heater wire and the outer cylindrical body. heat treatment furnace.