JPH04280419A - Heat treatment device - Google Patents

Abstract

PURPOSE:To provide a heat-treatment device which prevents thermal deformation at a high temperature without any difficulty in manufacture and secures a uniform thermal state at a region for storing a body to be treated. CONSTITUTION:A reaction pipe 10 is in a double-body configuration, namely a first constitution part which is a region where a body to be treated is stored and a second constitution part which is the other parts. Then, the first constitution part is formed by SiC, further a mounting part of a gas-introducing pipe and a gas-discharge pipe is provided at the second constitution part, and at the same time this second constitution part is formed by crystal.

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, and more particularly to an improvement in the structure of a heat treatment apparatus that performs heat treatment by introducing a process gas into a reaction tube containing an object to be heat treated.

0002

[Background Art] Conventionally, in the manufacturing process of semiconductor wafers, in order to perform various treatments such as CVD, oxidation, and diffusion on the semiconductor wafer, the object to be processed, such as the semiconductor wafer, is housed in a reaction tube and subjected to heat treatment. Heat treatment equipment is used.

FIG. 5 is a schematic diagram of an example of such a conventional heat treatment apparatus.

In the figure, a reaction tube 10 is made of quartz SiO2
A gas introduction pipe 12 and a gas discharge pipe 14 are formed at the lower part of the gas introduction pipe 12, respectively. The gas introduction tube 12 is formed to communicate the outside and the inside of the reaction tube 10, and the distal end of the gas introduction tube 12 extends to an upper position inside the reaction tube 10. On the other hand, the gas exhaust pipe 14 is formed by protruding from a lower position of the reaction tube 10.

Inside the reaction tube 10, semiconductor wafers 18 stacked on a boat 16 at predetermined intervals are housed. The boat 16 on which the semiconductor wafers 18 are installed is placed on a heat insulating cylinder 20. In addition, heat insulation tube 2
0 is moved up and down by a lifting mechanism 22 disposed below it, and this up and down movement moves the semiconductor wafer into the reaction tube 10.
It can be stored inside or taken out. The reaction tube 10 is completely sealed when the heat insulating cylinder 20 is raised by the elevating mechanism 22 and the semiconductor wafer 18 is completely accommodated in the reaction tube 10.

[0006] Also, a heating means 27 consisting of a heating element 24 and a heat insulating material 26 is disposed in an external region of the reaction tube 10. The heating element 24 is attached to the inner circumferential wall of the heat insulating material 26.

With this configuration, a process gas is introduced into the reaction tube 10 from the gas introduction tube 12, and the temperature inside the reaction tube 10 is brought to a predetermined temperature (
For example, it is heated to 1200°C). The semiconductor wafer 18 has been subjected to heat treatment by reaction of process gas under heating.

[0008]

In the conventional heat treatment apparatus described above, the reaction tube 10 is made of quartz SiO2, which releases few impurities during heat treatment.

However, the reaction tube 10 made of SiO2 has a problem in that it may be deformed when heated at a high temperature (approximately 1200° C.) for a long period of time. Therefore, it may be possible to form the reaction tube 10 using silicon carbide SiC, which has better heat resistance and is less likely to deform due to heat. According to the reaction tube made of this SiC, the problem of deformation due to heat can be solved. can.

However, when the entire reaction tube 10 is made of SiC, the gas introduction tube 12 and the gas discharge tube 14 are difficult to form because SiC has poor workability.
There has been a problem in that it is difficult to manufacture relatively complex components such as parts. Furthermore, SiC is S
Thermal conductivity is more than 10 times higher than that of iO2, and the reaction tube 1
When the entire reaction tube 10 is made of SiC, a large amount of heat is radiated from the lower region of the reaction tube 10 that is not covered with the heat insulating material 26. Therefore, the portion where the semiconductor wafer 18 is housed is also affected by the heat dissipation, and there is a problem that the thermal uniformity of that area may be impaired.

[0011] The present invention has been made to solve the above-mentioned problems, and its purpose is to reduce the possibility of thermal deformation even in high-temperature conditions and to ensure uniformity of heat in the storage area of objects to be processed. It is an object of the present invention to provide a heat treatment apparatus capable of processing the entire reaction tube relatively easily.

0012

Means for Solving the Problems In order to achieve the above object, the invention according to claim 1 provides a heat treatment apparatus for heat treating a plurality of objects to be treated in a reaction tube having a heating device around the reaction tube. , has a two-piece structure including at least a first component that is an area surrounded by the heating device and a second component that is the other part, and the first component has a better thermal conductivity than the second component. It is characterized by being formed from a member.

[0013] Furthermore, the invention according to claim 2 is characterized in that a groove having an exhaust port is provided at the joint between the first component and the second component constituting the reaction tube.

The invention according to claim 3 is characterized in that the first component is made of SiC and the second component is made of quartz.

[0015]

[Operation] According to the heat treatment apparatus having the above structure, the reaction tube is composed of two parts, and the first component part, which is the area surrounded by at least the heating device, is made of quartz, which is a common material for the heat treatment tool. The second component is made of a material with better thermal conductivity, such as SiC, than the second component made of, for example, SiC. As a result, due to the high thermal conductivity of SiC and other good thermal conductive materials, it is possible to ensure sufficient heat uniformity in the storage area for the objects to be processed, and for example, the heat treatment effect on the objects to be processed, such as semiconductor wafers, is uniform. It is possible to aim for

Furthermore, even when heat treatment is performed at a predetermined high temperature for a long time, SiC is less likely to be thermally deformed, so the reliability of the device is improved.

[0017] The other part, the second component, is made of a general material such as quartz (SiO2), and is therefore made of quartz, which has better workability than SiC or the like, and can have a relatively complex structure. Since the mounting portions of the gas inlet pipe and the gas discharge pipe can be formed as follows, there is no possibility that manufacturing difficulties will arise. Furthermore, since quartz has relatively poor heat transfer characteristics, heat radiation from the opening side of the reaction tube can be reduced.

Furthermore, according to the second aspect of the invention, since the joint portion of the first component and the second component can be sealed and evacuated, the two components that are in a high temperature state during heat treatment can be heated. High airtightness of the joint can be maintained.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings. In this embodiment, a vertical heat treatment apparatus for performing a diffusion process on a semiconductor wafer is used as an example.

FIG. 1 is a schematic sectional view showing the overall structure of a heat treatment apparatus according to an embodiment, and the same elements as those of the conventional apparatus shown in FIG. 5 are given the same reference numerals.

In the figure, the reaction tube 10 is the first component 10.
It is formed from two components: a and a second component 10b. The first component 10a is made of a heat-resistant material with good thermal conductivity, such as SiC, and the second component 10b is made of quartz (SiO2), which is a heat-resistant material. The first component is an outer region that surrounds the storage portion in which the semiconductor wafer 18 is stored.

[0022] Also, the gas introduction pipe 12 and the gas discharge pipe 14
are attached to the second component 10b of the reaction tube 10, respectively, and FIG. 2 is an explanatory diagram showing their attachment positions. As shown in the figure, a gas exhaust pipe 14 is provided at an angle of approximately 90° with respect to the gas introduction pipe 12, so that the inside and outside of the reaction tube 10 are in communication with each other.

Note that in the schematic cross-sectional view of FIG. 1, for convenience of explanation, the position of the gas introduction pipe 12 is shown shifted by approximately 90 degrees.

Furthermore, as shown in FIG. 1, in this embodiment, the gas introduction tube 12 is connected to the second component 1 of the reaction tube.
The attachment part 12a, which is the part that penetrates through 0b, and the reaction tube 1
It has a two-piece structure with an extension part 12b extending upward inside the 0. As for the materials of the gas introduction tube 12 constructed of these two bodies, the extension part 12b is made of SiC with high heat resistance, and the mounting part 12a is made of quartz with good workability, similarly to the reaction tube 10. are doing.

The uppermost end of the extended portion 12b of the gas introduction pipe 12 passes through the buffer plate 30. This buffer board 30
is horizontally installed slightly below the ceiling of the reaction tube 10, and its planar shape is as shown in FIG. 3, with a plurality of openings 32 formed therein. That is, the process gas introduced from the gas introduction pipe 12 is introduced between the buffer plate 30 and the ceiling of the reaction tube 10. Here, the process gas enters downward through the opening 32 of the buffer plate 30, is dispersed, and fills the reaction tube 10.

Next, the first component 10a and the second component of the reaction tube are
The configuration of the joint portion of the component 10b will be explained.

As shown in FIG. 1, both components 10
A groove 34 is formed at the joint between a and 10b. This groove 34 is formed by forming a continuous recess on the joint surface of the second component 10b with the first component 10a. Then, a seal exhaust pipe is pulled out from the groove 34, which is closed by joining the first component 10a, and is constantly exhausted by an exhaust device (not shown).

The installed state of this seal exhaust pipe 36 is shown in FIG.
is shown. FIG. 4 is a partially cutaway horizontal cross-sectional view showing the installed state of the seal exhaust pipe, in which the communication port 36a of the seal exhaust pipe 36 communicates with the groove 34.

Furthermore, in this embodiment, at the junction between the lid 38 (see FIG. 1) on which the heat-insulating cylinder 20 is placed and the second component 10b of the reaction tube joined to this lid, Seal exhaust means are formed. That is, a groove 40 is formed in the lower joint surface of the second component 10b, and the groove 40 is closed by joining with the lid part 38, and the seal exhaust pipe 42 is pulled out from this groove 40. ing. Note that in FIG. 1, the seal exhaust pipe 42 is shown, and the seal exhaust pipe 36 is not shown because it is located behind the seal exhaust pipe 42.

As described above, in this embodiment, the grooves 34 and 40 are formed at both the upper and lower joints of the second component 10b of the reaction tube, and from each groove 34 and 40, as shown in FIG. Seal exhaust pipes 36 and 42 have been withdrawn as shown. In the figure, a communication port 42a of the seal exhaust pipe 42 communicates with the groove 40.

According to the heat treatment apparatus having the above structure, the area of the reaction tube that is the area surrounded by the heating apparatus (not shown), that is, the area that surrounds the area in which the semiconductor wafer 18 as the object to be processed is accommodated. Since the first component 10a is made of SiC, when heating by the heating means 27 is started,
Since the first component 10a has high thermal conductivity, it quickly becomes high temperature, and the entire first component 10a is in a uniformly heated state. As a result, the heating effect on each semiconductor wafer 18 becomes substantially uniform, making it possible to perform uniform heat treatment.

Furthermore, since SiC has little deformability even under high temperature conditions, there is no risk of problems due to thermal deformation of the reaction tube 10.

Furthermore, the second component 10b has a gas inlet pipe 12 and a gas exhaust pipe 14 attached thereto, and in this embodiment, seal exhaust pipes 36 and 42 are attached thereto, so that the structure is complicated. It becomes. However, since the second component 10b is made of quartz, its workability is relatively good, and there is no fear that the work will be difficult. Furthermore, since quartz has a lower heat transfer coefficient than SiC, it is possible to reduce heat radiation from the lower end opening side of the reaction tube 10, and it becomes easy to control the temperature by making the wafer storage zone into a soaking zone.

Furthermore, the first component 10a and the second component 1
The state of connection with 0b is determined by the groove 34 formed at the joint between the two.
By drawing negative pressure from the seal exhaust pipe 36,
The lower end of the first component 10a can be attached to the upper end of the second component 10b, and the gap between the two can be eliminated to ensure airtightness. Furthermore, even if a gap occurs, the gas that has entered the gap can be exhausted, thereby preventing gas leakage to the outside. Further, in this embodiment, the groove 40 and the seal exhaust pipe 4 are also formed at the joint between the second component 10b and the lid 38 which is the bottom thereof.
2 is provided. Therefore, by performing evacuation using this seal exhaust pipe 42, complete airtightness is similarly ensured on the lower side of the second component 10b. This not only makes it possible to prevent deterioration of airtightness due to the formation of two reaction tubes 10, but also makes it possible to ensure higher airtightness than before in the entire apparatus.

Furthermore, in this embodiment, since the gas introduction tube 12 is constructed in two pieces, the extension portion 12b of the gas introduction tube 12 can be easily removed during cleaning or the like. That is, since the extension part 12b and the attachment part 12a are both connected inside the reaction tube 10, there is no problem even if there is some leakage, and since they are simply rubbed together to cover them, attachment and detachment are extremely easy. It is. By this removal and cleaning, it is possible to easily remove stains caused by adhesion of reaction products on the gas introduction pipe 12.

[0036]

[Effects of the Invention] As explained above, according to the heat treatment apparatus according to the present invention, it is possible to effectively prevent deformation of the reaction tube under high temperature conditions and ensure uniformity of heat in the heated portion of the object to be treated. Furthermore, difficulties in machining the parts to which various pipes are attached can be effectively prevented.

[0037] Thereby, it is possible to effectively achieve functional reliability and failure prevention of the heat treatment apparatus without making it difficult to manufacture the apparatus.

[Brief explanation of the drawing]

FIG. 1 is a schematic vertical cross-sectional view showing the overall configuration of an embodiment.

FIG. 2 is an explanatory diagram showing the installation state of a gas introduction pipe and a gas discharge pipe in the embodiment.

FIG. 3 is a plan view of the buffer plate of the embodiment.

FIG. 4 is a partially cutaway sectional view showing the installed state of the seal exhaust pipe of the embodiment.

FIG. 5 is a schematic cross-sectional view showing an example of a conventional heat treatment apparatus.

[Explanation of symbols]

10 Reaction tube 10a First component 10b Second component 12 Gas introduction tube 14 Gas discharge tube 16 Boat 18 Semiconductor wafer 20 Heat retention tube 22 Lifting mechanism 24 Heating element 26 Heat insulating material 30 Buffer plate 34, 40 Groove 36, 42 Seal Exhaust pipe
TE033001

Claims (3)

[Claims] 1. A heat treatment apparatus for heat-treating a plurality of objects to be treated in a reaction tube having a heating device around the reaction tube, wherein the reaction tube has at least a first component that is an area surrounded by the heating device and the rest. A heat treatment apparatus characterized in that it has a two-piece construction with a second component, which is a part of the first component, and the first component is made of a material with better thermal conductivity than the second component. 2. The heat treatment apparatus according to claim 1, wherein a groove having an exhaust port is provided at a joint between a first component and a second component constituting the reaction tube. . 3. The heat treatment apparatus according to claim 1, wherein the first component is made of SiC and the second component is made of quartz.