JPH07122512A - Impurity diffusion furnace - Google Patents

Abstract

PURPOSE:To prevent the sealing between members due to the adhesion of an adhesion source by covering the joint between components which are exposed to the inside of a reaction chamber and are extremely in contact with an adhesion rejection plate formed at the components on an impurity source supply side. CONSTITUTION:A reaction pipe 11 is placed at a disk-shaped lid 12 and a cylindrical temperature-preservation cylinder placement stand 12B is formed at the center of the lid 12. Also, an adhesion rejection plate 13A for covering the joint with the temperature-preservation cylinder placement stand 12B with a spacing is formed in an orbit outside the outer-peripheral side surface of a temperature-preservation cylinder 13. Also, an exhaust hole 11B is formed at the lower part of the reaction pipe 11 and a source gas is evacuated. Then, the adhesion rejection plate 13A prevents the source gas from being adhered for the flow of the source gas. Then, since the adhesion rejection plate 13A has a spacing at an area to the joint, the adhesion rejection plate 13A cannot be sealed to the joint, thus reducing the replacement frequency of components and improving production efficiency.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an impurity diffusion furnace and can be used in the field of manufacturing semiconductor devices including a step of introducing impurities into a semiconductor wafer.

[0002]

2. Description of the Related Art Conventionally, as this type of impurity diffusion furnace,
As shown in FIG. 6, a reaction tube (reaction chamber) 1, a heater 2 surrounding the reaction tube 1, a lid 3 for enclosing gas, a heat insulating cylinder 4 placed on the lid 3, and a plurality of wafers W are provided. A boat 5 supported in parallel with each other is roughly configured. This impurity diffusion furnace has a vertical structure, and a gas supply port 1A for introducing phosphorus source is provided in the upper part of the reaction tube 1, and a gas exhaust port 1B is provided in the lower part. The heat-retaining cylinder 4 placed on the lid 3 has a function of maintaining a soaking length of heat.

The impurity diffusion furnace shown in FIG. 7 has a horizontal structure, and the boat 5 is placed directly in the reaction tube 1.

[0004]

However, in the vertical type impurity diffusion furnace, the boat 5 is placed on the heat retaining tube 4, and the heat retaining tube 4 is placed on the lid 3. However, there is a problem in that the members adhere to the joint between the boat 5 and the heat insulating cylinder 4 or the joint between the heat insulating cylinder 4 and the lid 3, and the members adhere to each other. In FIG. 6, 6 indicates an adhered substance. Further, in the horizontal impurity diffusion furnace, as shown in FIG. 7, since the boat 5 is directly placed in the reaction tube 1, there is a problem that the boat 5 and the reaction tube 1 are fixed to each other by the deposit 6. When the boat 5 is fixed to the joining member in this way, there arises a problem that the boat 5 cannot be taken out from the reaction tube 1 by the boat transfer means or the boat 5 or the wafer W is damaged. In addition to taking out the boat 5,
There is also a problem in that each member cannot be removed, and it is impossible to replace the part or clean the deposit 6 that causes generation of particles.

The problem to be solved by the present invention lies in what kind of means should be taken to obtain an impurity diffusion furnace which can prevent sticking between members due to adhesion of an impurity source and improve work efficiency. is there.

[0006]

The invention according to claim 1 of the present application covers a joint portion between parts which are exposed in the reaction chamber and which are in considerable contact with each other, with an adhesion prevention plate formed on the part on the impurity source supply side, Moreover, the formation of a gap between the adhesion prevention plate and the other component is the solution.

The invention according to claim 2 is characterized in that an adhesion preventing plate is provided so as to project on the surface near the joint of one of the parts which are exposed in the reaction chamber and which are in considerable contact with each other and are located on the impurity source supply side. Circulating an inert gas through the joint is the solution.

[0008]

In the invention according to claim 1 of this application, since the adhering prevention plates provided on the parts on the impurity source supply side cover the joints between the parts that make considerable contact, the impurity source is prevented from adhering to the joints. There is an action. Since the adhesion prevention plate provided on one of the parts to be phase-joined forms a gap between the other part and the other part, it is possible to prevent the adhesion of the other part and the adhesion prevention plate due to the adhered matter of the impurity source. .
Therefore, for example, the boat, the heat insulating cylinder, etc. can be smoothly taken out, and the interruption of the process can be prevented.

Further, in the invention of claim 2, in addition to the effect of the invention of claim 2 described above, since an inert gas is circulated in the joint portion, it is ensured that the impurity source reaches the joint portion. It has the effect of blocking.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the impurity diffusion furnace according to the present invention will be described below with reference to the embodiments shown in the drawings.

(First Embodiment) FIG. 1 shows a first embodiment of the present invention.
FIG. The present embodiment is an example in which the present invention is applied to an impurity diffusion furnace having a vertical structure. In the figure, 11 is a reaction tube as a reaction chamber, and this reaction tube 11 is placed on a disk-shaped lid 12. The lid 12 is formed with a jetty portion 12A projecting upward at the peripheral edge of the upper surface, and a columnar heat retaining tube mounting table 12B is formed in the center of the lid. The reaction tube 11 is
The lower end of the lid 1 is placed on the jetty 12A of the lid 12.
It is designed to be joined with 2. In addition, as shown in FIG. 1, the reaction tube 11 and the lid 12 are provided under the inner wall of the reaction tube 11.
11A with a hanging structure that covers the joints of
Are formed by orbiting. In addition, this adhesion prevention plate 11
A is set so as to have a gap with the joint portion.

Further, at the lower part of the outer peripheral side surface of the heat insulating cylinder 13 placed on the heat insulating cylinder mounting table 12B of the lid 12, there is provided an attachment prevention plate 13A having a hanging structure for covering the joint with the heat insulating cylinder mounting table 12B. It is formed by orbiting.

Further, an adhesion prevention plate 14A having the same shape as the heat retaining cylinder 13 is formed on the lower peripheral surface of the boat 14 placed on the heat retaining cylinder 13 to cover the joint portion with the heat retaining cylinder 13. . Although a wafer is set in the boat 14, illustration is omitted.

An exhaust hole 11B is formed in the lower part of the reaction tube 11, and the source gas is exhausted from the exhaust hole 11B at a predetermined flow rate.

With the above structure, each of the adhesion prevention plates 14A, 13A, 11A has a function of preventing the source gas from adhering to each joint portion against the flow of the source gas. Also, the adhesion prevention plate has a gap between the adhesion part,
Since it is separated from the other joint component, the adhesion prevention plate and the other joint component are not fixed by the adhesion of the source gas. Therefore, the lid 12 of the impurity diffusion furnace and the heat insulating cylinder 13
It is possible to smoothly load and unload the boat 14 by soft landing.

(Embodiment 2) FIG. 2 is a sectional view of a main portion of Embodiment 2, showing a lateral impurity diffusion furnace. 2 in the figure
Reference numeral 1 denotes a reaction tube, and a jetty-shaped boat mounting table 21A for mounting the boat 22 is formed on the inner wall of the bottom of the reaction tube 21. At the lower part of the frame of the boat 22 mounted on the mounting table 21A, an adhesion prevention plate 22A is formed, which covers both sides of the joint with the boat mounting table 21A. The adhesion prevention plate 22A is set so that a gap is formed between the adhesion prevention plate 22A and the joint portion as in the first embodiment. In this embodiment as well, since the joint portion is not fixed, the boat 2 from the reaction tube 21
2 can be carried out smoothly and production efficiency can be improved.

In the figure, W indicates a wafer.

(Embodiment 3) FIG. 3 is a sectional view of the essential portions of Embodiment 3, showing the structure of an embodiment in which the present invention is applied to a vertical impurity diffusion furnace.

In the figure, 31 is a reaction tube, 32 is a lid, 33 is a heat retaining cylinder, and 34 is a boat. The reaction tube 31 has a lid 3
It is placed on the upper surface of the lid 2 and can be airtightly joined to the upper surface of the lid 32 by the lower flange portion 31A. An exhaust hole 31A is formed in the lower part of the reaction tube 31. Insulation cylinder 33
Is a tubular body that penetrates in the vertical direction, and the lower half is a lid 32.
It has a large diameter so that it has stability when placed on top. An inert gas flow hole 33A is intermittently formed at the lower end of the heat insulating cylinder 33. Further, the inert gas flow holes 33B and 33C are also intermittently formed in the middle position and the upper part of the lower half part. And the inert gas flow hole 3
The cover 3 that hangs downwardly on the outer side of 3C.
3D is formed by orbiting. The cover 33D regulates the inert gas (for example, N ₂ ) so as not to flow upward. The upper half of the heat insulating cylinder 33 is thinner than the lower half so that the boat 34 can be placed on the upper end. In addition, a groove is formed in the bottom of the boat 34 so that an inert gas flow hole 34B that communicates with the through hole of the heat retaining cylinder 33 in a state where the boat 34 is joined to the heat retaining cylinder 33 is formed. Further, an adhesion prevention plate 34A that guides the inert gas discharged from the flow hole downward is formed in the lower portion of the boat 34. The adhesion prevention plate 34A can prevent the impurity source supplied from above from adhering to the adhesion prevention plate 34A, and can prevent the impurity source from approaching the joint portion by circulating the inert gas in the adhesion prevention plate 34A. In this embodiment, since the upper half part and the lower half part of the heat insulating cylinder 33 are connected to each other by the slope, the source gas is guided to the exhaust hole 31A along the slope, and the reverse return of the source gas can be prevented.

(Embodiment 4) FIG. 4 is a cross-sectional view of the essential portions of the present Embodiment 4, showing a vertical impurity diffusion furnace. In this embodiment, a brim-shaped attachment prevention plate 44A is provided on the lower peripheral edge of the boat 44.
To form an inert gas supply hole 41A at the bottom of the reaction tube 41.
And the exhaust hole 41B of the reaction tube 41 is formed at a position higher than the adhesion prevention plate 44A. Therefore, the adhesion prevention plate 44A has an effect of preventing the source gas from reaching the joint with the heat insulating cylinder 43.

(Embodiment 5) FIG. 5 is a cross-sectional view of essential parts of Embodiment 5, showing a vertical impurity diffusion furnace. In this embodiment, the inert gas supply hole 5 formed in the lower part of the reaction tube 51
The gas flow pipe 51 is formed so that the inert gas introduced from 1A circulates in the reaction pipe 51.
A plurality of gas discharge holes 51C are formed on the inner circumferential wall of 1B. Further, since the heat insulating cylinder 53 is made narrower than the boat bottom portion 53A, the source gas is less likely to adhere to the joint between the boat 54 and the heat insulating cylinder 53.

Further, an exhaust hole 51 formed in the reaction tube 51
Since D is located below the boat bottom 53A, the inert gas is prevented from going above the boat bottom 53A.

Although the respective embodiments of the present invention have been described above, the present invention is not limited to the embodiments, and various design changes can be made accompanying the gist of the configuration.

[0024]

As is apparent from the above description, according to the inventions of claims 1 and 2 of the present application, it is possible to prevent the impurity source from adhering to the joints of the components, and to prevent the components from sticking to each other. It becomes possible. For this reason, the frequency of replacement of parts is reduced, and the production efficiency is improved.

[Brief description of drawings]

FIG. 1 is a sectional view of an essential part showing a first embodiment of the present invention.

FIG. 2 is a sectional view of an essential part showing a second embodiment of the present invention.

FIG. 3 is a cross-sectional view of essential parts showing a third embodiment of the present invention.

FIG. 4 is a cross-sectional view of the essential parts showing Embodiment 4 of the present invention.

FIG. 5 is a cross-sectional view of essential parts showing Embodiment 5 of the present invention.

FIG. 6 is a sectional view of a conventional example.

FIG. 7 is a sectional view of a conventional example.

[Explanation of symbols]

 11 ... Reaction tube 11A ... Adhesion blocking plate 11B ... Exhaust hole 12 ... Lid 13 ... Heat insulation cylinder 13A ... Adhesion blocking plate 14 ... Boat W ... Wafer

Claims (2)

[Claims] 1. A joint portion between parts which are exposed in the reaction chamber and which are in substantial contact with each other is covered with an adhesion prevention plate formed on the parts on the impurity source supply side, and a gap is provided between the adhesion prevention plate and the other part. An impurity diffusion furnace characterized by being formed. 2. An adhesion-preventing plate is projected on a surface of a part near the joint of one of the parts that are exposed in the reaction chamber and located on the impurity source supply side, and an inert gas is circulated to the joint. An impurity diffusion furnace characterized by: