JP2002353157A - Heat treatment apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a heat treatment apparatus which can reduce the installation floor area thereof, can heat chemical substances and processing substances under optimum temperature conditions, respectively, even when the processing substance is batch-processed by using the chemical substance having toxicity, and is superior in maintenance and safety for increasing the manufacturing yield of the processing substance. SOLUTION: An antimonous oxide d is placed in a hermetic heating tube 3 and is heated by a second heater 4, provided outside an outer periphery of the heating tube 3a, to produce a sublimation gas (reaction gas) of the antimonous oxide d. Furthermore, a semiconductor wafer W is disposed in a vertical hermetic process tube 1 and is heated by a first heater 2, provided outside an outer periphery of the process tube 1; and the sublimation gas is then introduced from an introduction port 1a which is provided in a part to be heated by the first heater 2 of the process tube 1 at heating and is connected hermetically to the heating tube 3.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heat treatment apparatus used for a process of diffusing a dopant into a semiconductor wafer.

[0002]

2. Description of the Related Art When forming an n-type region by diffusing a dopant such as antimony into a semiconductor wafer, for example, a horizontal heat treatment apparatus shown in FIG. 2 is used. In FIG. 2, this conventional heat treatment apparatus is installed in a clean room. Inside a cylindrical heater 52 covered with a heat insulating wall 52a, a cylindrical horizontally long heat processing apparatus capable of batch-processing a plurality of semiconductor wafers W is provided. And a semiconductor wafer W mounted on the boat 53 is loaded and unloaded from a furnace port (not shown) provided at one end of the process tube 51. A crucible 54 in which antimony trioxide (Sb ₂ O ₃ ) d, which is a solid source of a dopant, is placed in the process tube 51.
Is arranged. In this conventional heat treatment apparatus, a carrier gas such as N ₂ gas flows from a supply port 51a provided at the other end of the process tube 51 in a direction indicated by an arrow “X” in the drawing, and By heating the semiconductor wafer W and the antimony trioxide d by the heater 52, the sublimated antimony trioxide d was caused to flow over the surface of the semiconductor wafer W with the carrier gas to thermally diffuse the antimony into the semiconductor wafer W. .

[0003]

However, in the above-described conventional heat treatment apparatus, since the horizontally long process tube 51 is used for batch processing the semiconductor wafer W, the installation floor area of the apparatus is large. In addition, the clean room had to be large, and the equipment cost was high. In addition, it is difficult to secure the sealability and ventilation from the viewpoint of structure, and there is a problem in safety and maintainability when handling toxic chemicals such as antimony trioxide d. Also,
A semiconductor wafer W and antimony trioxide d are arranged in a process tube 51 and heated by a heater 52,
Since these processing temperatures cannot be controlled independently, the semiconductor wafer W and antimony trioxide d may not be heated under the optimum temperature conditions. As a result, unevenness in the thermal diffusion treatment of antimony may occur, and the yield of the object to be treated may be reduced.

[0004] In view of the above-mentioned conventional problems, the present invention can reduce the installation floor area of the apparatus, and even when the object to be treated is batch-processed using a toxic chemical substance. It is an object of the present invention to provide a heat treatment apparatus which can heat a chemical substance and an object to be processed under optimum temperature conditions and can improve the yield of the object to be processed and which is excellent in maintainability and safety.

[0005]

A heat treatment apparatus according to the present invention comprises:
A heat treatment apparatus that generates a reaction gas by heating a solid source or thermally decomposes a raw material gas, and performs heat treatment on the object using the reaction gas. A possible process tube, a first heater provided on the outer periphery of the process tube, a sealable heating tube for generating the reaction gas, and a second heater provided on the outer periphery of the heating tube. And a heater for introducing the reaction gas from the heating tube into the process tube at a portion of the process tube heated by the first heater. The heating tube is air-tightly connected (claim 1).

In the heat treatment apparatus configured as described above,
Because a vertical sealable process tube is used,
Lateral spread of the device can be minimized. Further, the object to be processed and the solid source or the source gas can be independently heated by the first and second heaters in the process tube and the sealable heating tube. Even when the object to be processed is batch-processed using the substance, the object to be processed and the solid source or the source gas can be heated under optimum temperature conditions. In addition, by providing the above-described inlet at the portion of the process tube heated by the first heater, it is possible to introduce the reaction gas generated in the heating tube into the process tube while minimizing the temperature drop. .

Further, in the heat treatment apparatus (claim 1), it is preferable that a supply port of a process gas supplied into the process tube is provided below the introduction port (claim 2). In this case, the flow of the process gas can prevent the reaction gas from flowing downward from the inlet.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a preferred embodiment of a heat treatment apparatus according to the present invention will be described with reference to the drawings.
FIG. 1 is a cross-sectional view illustrating a main configuration of a heat treatment apparatus according to an embodiment of the present invention. In the following description, a case in which a solid diffusion furnace for thermally diffusing antimony into the semiconductor wafer W is configured will be described for easy comparison with the conventional example. In the figure, a heat treatment apparatus of the present embodiment includes a vertical sealable process tube 1 for heating a semiconductor wafer W as an object to be processed, and a cylindrical process tube provided outside the outer periphery of the process tube 1. A first heater 2, a hermetically connected heating tube 3 that is hermetically connected to the process tube 1, and generates a reaction gas;
A cylindrical second tube provided outside the outer periphery of the heating tube 3
Heater 4.

Inside the heating tube 3, for example, antimony trioxide d is placed as a solid source in a crucible 5, and the heating tube 3 has a door air-tightly attached to one end opening thereof. 6 to crucible 5 above
Can be put in and out. Further, an introduction pipe 7 for introducing a carrier gas such as N ₂ gas is connected to the heating tube 3, and the reaction tube is heated by radiant heat from the second heater 4 to heat the antimony trioxide d. A sublimation gas of antimony trioxide d as a gas is generated and introduced into the process tube 1 by the carrier gas.

More specifically, a thin tube portion 3a having a tip spherical portion 3a1 is provided on the other end side of the heating tube 3, and the tip spherical portion 3a1 is connected to the first heater 2 and a soaking tube described later. 13 are respectively provided with holes 2b and 13
a, and sublimated gas is introduced into the process tube 1 by a carrier gas by being hermetically connected to a hemispherical seat 1b provided around the inlet 1a on the process tube 1 side. The inlet 1a is provided at a portion of the process tube 1 heated by the first heater 2, and is configured to minimize a decrease in the temperature of the sublimation gas. The second heater 4 is covered with a tubular heat insulating wall 4a, and has a sealing property between the tip spherical portion 3a and the hemispherical seat 1b together with the heating tube 3 by a tubular support container 8. Is secured to the inner surface (not shown) of the outer wall of the device.

The process tube 1 is configured such that a boat 14 loaded with semiconductor ware W is carried in / out from the lower end opening. Also, the process tube 1
Its inner space is mixed gas of sublimated gas and the carrier gas from the inlet 1a is introduced, further from the supply port 1c provided below the inlet 1a of the N ₂ gas or the like to the exhaust port 1d side provided in the upper The semiconductor wafer W is configured to be heated by radiant heat from the first heater 2 in a state where the process gas is supplied.

The exhaust port 1 of the process tube 1
An exhaust pipe 9 for exhausting a gas such as a sublimation gas introduced into the process tube 1 to the outside is provided at the joint 10.
Are connected via Specifically, the joint 10
As shown in the figure, for example, a ball joint type is used, and a spherical surface formed around the inside surface of one end 9a of the exhaust pipe 9 formed in a hemispherical shape and the exhaust port 1d is used. The process tube 1 and the exhaust pipe 9 are connected by bringing the outer surface of the shape part 1e into contact with each other. The joint 10 includes a pressing member (not shown) for pressing the exhaust pipe 9 and the mantle heater 11 wound around the exhaust pipe 9 from above to below. It is designed to secure sex.
In addition, the mantle heater 11 prevents the antimony trioxide d from depositing from the sublimation gas and attaching to the inner surface of the exhaust pipe 9 as a by-product by heating the exhaust pipe 9. Further, a cold trap section 16 is provided on the other end side of the exhaust pipe 9, and by cooling the exhaust pipe 9, the sublimation gas is cooled to remove toxic antimony trioxide d from the gas discharged to the outside. It is configured to deposit and remove.

The first heater 2 has a cylindrical heat insulating wall 2a.
At the upper end of the heat insulating wall 2a.
The above-mentioned joint part 10 is inserted through the heat insulating material 12. A cylindrical heat equalizing tube 13 is disposed between the first heater 2 and the process tube 1, and uniformly transmits radiant heat from the first heater 2 to the process tube 1. The configuration is such that thermal diffusion processing can be performed on a plurality of semiconductor wafers W at a desired processing temperature without causing temperature unevenness.

The boat 14 is arranged so as to be able to ascend and descend in the process tube 1 by an elevating mechanism (not shown), and is configured so that a plurality of semiconductor wafers W can be mounted and batch-processed. In detail, the boat 14 includes, for example, a top plate 14a formed in a disc shape, a long support 14b connected to the top plate 14a, and supporting the top plate 14a, and a mounting on which the support 14b is mounted. Board 1
4c, the semiconductor wafer W is held one by one at a predetermined interval by a groove (not shown) provided in the above-mentioned column 14b, so that the sublimation gas flows over the surface of each semiconductor wafer W. Flow evenly. Thereby, it is possible to prevent the occurrence of processing unevenness in the diffusion treatment of antimony.

At the lower end of the boat 14, a floor plate 14d also serving as a furnace port door is provided so that the lower end opening of the process tube 1 can be sealed. In addition, a heat barrier portion 14e is provided between the mounting plate 14c and the floor plate 14d to suppress transmission of radiant heat from the first heater 2 to the floor plate 14d during heat treatment. On the top plate 14a of the boat 14, a tray 15 composed of a bottomed case made of quartz and having one end opened is detachably mounted with its one end opening facing the exhaust port 1d. I have. Thereby, even if the surplus sublimation gas is cooled by contacting the inner surfaces of the exhaust pipe 9 and the joint portion 10 and adheres to those inner surfaces, even if it falls from the exhaust port 1d, it is received and collected by the tray 15. can do.

In the heat treatment apparatus configured as described above,
Since the vertically-closable process tube 1 is used, the lateral spread of the device can be minimized, and the installation floor area of the device can be reduced.
Further, since the semiconductor wafer W and the antimony trioxide d are independently heated by the first and second heaters 2 and 4 in the process tube 1 and the sealable heating tube 3, respectively, the toxic trioxide is used. Even when the semiconductor wafer W is batch-processed using antimony d, the semiconductor wafer W and antimony trioxide d can each be heated at desired temperature conditions. Moreover, the above-mentioned inlet 1
Since “a” is provided in the portion of the process tube 1 heated by the first heater 2, it is possible to introduce the sublimation gas generated in the heating tube 3 into the process tube 1 while minimizing the temperature drop. In addition, it is possible to enhance the uniformity of the heat treatment and prevent the antimony trioxide d from being precipitated from the sublimation gas due to the temperature decrease.

In this embodiment, since the supply port 1c is provided below the inlet 1a, the reaction gas introduced into the process tube 1 from the inlet 1a is supplied to the supply port 1c.
Can be prevented from flowing from the inlet 1a to the low-temperature portion at the lower end of the process tube 1 by the flow of the process gas from above, and antimony trioxide d can be prevented from being precipitated from the reaction gas at the lower end. . As a result, it is possible to prevent the deposited antimony trioxide d from depositing at the lower end, and to facilitate the maintenance work.

In the above description, a solid diffusion furnace is constructed in which antimony trioxide d as a solid source is sublimated and introduced into the process tube 1 with a carrier gas to thermally diffuse antimony into the semiconductor wafer W. Although the case has been described, the present invention is not limited to this, and any device may be used as long as the reaction gas heated and generated in the heating tube 3 is introduced into the process tube 1 to cause a chemical reaction with the object to be processed. Specifically, silane (Si
A silicon gas (reactive gas) obtained by thermally decomposing a source gas such as H ₄ ) is introduced into the process tube 1 and a silicon oxide film (SiO ₂ ) or the like is formed on the surface of the semiconductor wafer W in a silicon-rich atmosphere. The present invention can also be suitably used in a vapor deposition furnace for chemical vapor deposition, an epitaxial furnace used for forming a high-purity silicon crystal, and the like. Further, in addition to the above description, ZnAs ₂ and ZnSb ₃ etc., ZnAs, Cd
₃ P _2, and Mg ₃ P ₂ solid sources used respectively, A
lGaAsSb, AlGaP, ZnGaAsP,
And InP-based compound semiconductors may be formed.

[0019]

The present invention configured as described above has the following effects. According to the heat treatment apparatus of the first aspect, since the lateral spread of the apparatus can be minimized, the installation floor area of the apparatus can be reduced. Therefore, the apparatus can be installed without increasing the size of the clean room, and equipment costs can be reduced. Further, since the object to be processed and the solid source or the raw material gas are independently heated by the first and second heaters in the sealable process tube and the sealable heating tube, chemical substances such as a toxic solid source are used. In the case of batch processing of workpieces using, the safety can be easily ensured, and the workpieces and the chemical substances are heated at desired temperature conditions to increase the yield of the workpieces. be able to. Moreover, since the temperature drop of the reaction gas generated in the heating tube can be minimized and introduced into the process tube, it is possible to prevent a chemical substance from being precipitated as a by-product from the reaction gas, Preventing deposited by-products from accumulating in the apparatus, making maintenance work easier.

According to the heat treatment apparatus of the present invention, it is possible to prevent the reaction gas from flowing downward from the inlet by the flow of the process gas, so that the reaction gas flows to the low-temperature portion at the lower end of the process tube. Flow can be prevented, and the by-product can be prevented from being precipitated from the reaction gas at the lower end. As a result, the deposited by-product can be prevented from being deposited on the lower end portion, and the maintenance work can be facilitated.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a main configuration of a heat treatment apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view illustrating a configuration of a main part of a conventional heat treatment apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Process tube 1a Inlet 1c Supply port 1d Exhaust port 2 First heater 3 Heating tube 4 Second heater

Continued on the front page (72) Inventor Yoshiharu Fukuyama 229 Kahata-cho, Tenri-shi, Nara Prefecture F-term (reference) 5F045 BB08 BB20 DP19 EB02 EB10 EE02 EG08 EK06 EK21

Claims (2)

[Claims] 1. A heat treatment apparatus for generating a reaction gas by heating a solid source or thermally decomposing a source gas, and performing heat treatment on the object using the reaction gas. A vertical sealable process tube, a first heater provided on the outer periphery of the process tube, a sealable heating tube for generating the reaction gas, and an outer periphery of the heating tube. And a second heater provided at a portion of the process tube heated by the first heater, and an introduction port for introducing the reaction gas from the heating tube to the inside of the process tube is provided. A heat treatment apparatus, wherein the heating tube is hermetically connected to the inlet. 2. The heat treatment apparatus according to claim 1, wherein a supply port for a process gas supplied into the process tube is provided below the inlet.