JP3278011B2 - Heat treatment equipment - Google Patents

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.

[0002]

2. Description of the Related Art For example, in the production of semiconductor wafers,
Various heat treatment apparatuses are used for performing processes such as CVD, oxidation, diffusion, and annealing. As this type of heat treatment apparatus, a vertical reaction tube including an inner tube and an outer tube having heat resistance and corrosion resistance is provided on a metal manifold, and a wafer to be processed, which is accommodated in the reaction tube, is placed under a heating atmosphere. There is an apparatus in which a processing gas is supplied from an exhaust pipe, and the exhaust gas after the processing is exhausted by being lowered between the inner pipe and the outer pipe. In this heat treatment apparatus, it is possible to perform in-plane uniform processing on the wafer by the flow of the processing gas;
In addition, since a structure for achieving airtightness between the manifold and the reaction tube can be easily applied to the manifold, it is particularly suitable for heat treatment under reduced pressure (for example, reduced pressure CVD).

In the heat treatment apparatus, even in the case of heat treatment using, for example, oxygen (O ₂ ) and corrosive hydrogen chloride (HCl) as a processing gas, hydrogen chloride itself in a dry state is relatively inert. In addition, since the processing gas flows upward from below the inside of the reaction tube (specifically, inside the inner tube), there is almost no problem that the metal member below the inside of the inner tube is corroded. Therefore, in that point, unlike the heat treatment apparatus in which the processing gas is caused to flow horizontally into the reaction tube as disclosed in Japanese Patent Application Laid-Open No. 2-138730, the lower metal member in the inner tube is protected from corrosion. There is not much need to take measures.

[0004]

However, in the heat treatment apparatus, the treated exhaust gas may become highly corrosive, for example, containing moisture in hydrogen chloride. When the exhaust gas (including the corrosive products) descends between the inner tube and the outer tube of the reaction tube and is exhausted, it contacts the manifold through the lower end of the inner tube and the outer tube of the reaction tube, There was a problem that the manifold corroded.

As a means for solving this problem of corrosion, it is conceivable that the reaction tube has an integral structure in which the lower end of the inner tube and the lower end of the outer tube are connected. It is difficult to adopt because there is a problem that cleaning and handling become difficult.

Accordingly, an object of the present invention is to prevent corrosion caused by corrosive exhaust gas passing between the separated lower end portions of the inner pipe and the outer pipe and coming into contact with the manifold, thereby improving the durability of the manifold. An object of the present invention is to provide a heat treatment apparatus capable of improving the temperature.

[0007]

In order to achieve the above object, an invention according to a first aspect of the present invention is to provide an inner tube having heat and corrosion resistance and a concentric outer tube on a metal manifold. In a heat treatment apparatus configured to supply a processing gas from below under a heated atmosphere to the accommodated object to be processed and exhaust the exhaust gas after processing between the inner pipe and the outer pipe, an inner pipe in contact with the manifold is provided. A predetermined gap is formed between the lower end and the lower end of the outer tube for ejecting the seal gas.

According to a second aspect of the present invention, in the first aspect of the invention, the manifold is formed in a flat ring shape, and the gas after processing is exhausted to a lower portion of the outer tube. Is formed.

Further, according to a third aspect of the present invention, an inner tube and an outer tube having heat resistance and corrosion resistance are provided concentrically on a metal manifold, and the object to be processed accommodated in the inner tube is placed under a heating atmosphere. In a heat treatment apparatus that supplies a processing gas from and exhausts the exhaust gas after the processing through the space between the inner tube and the outer tube, between the lower end of the inner tube in contact with the manifold and the lower end of the outer tube. And a sealing member for sealing between them. The seal member
Is preferably a fluoro rubber O-ring (contract
Claim 4).

[0010]

According to the first aspect of the present invention, the gap between the separated lower ends of the inner pipe and the outer pipe that are in contact with the manifold is sealed by the seal gas, so that the corrosion of the manifold caused by the contact of corrosive exhaust gas is prevented. And the durability of the manifold can be improved.

According to the second aspect of the present invention, it is not necessary to form an exhaust pipe section in the manifold, and the manifold can be formed flat, so that the structure of the manifold can be simplified and downsized.

According to the third aspect of the present invention, the gap between the lower end of the inner pipe and the lower end of the outer pipe which is in contact with the manifold is sealed by the seal member. This can be prevented with a simple structure and at low cost.

[0013]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings.

FIG. 1 is a cross-sectional view showing one embodiment of a heat treatment apparatus according to the present invention. The heat treatment apparatus 1 of this embodiment has a flat ring-shaped manifold 2 made of, for example, stainless steel and is horizontally mounted on a base plate (not shown). In preparation.
An inner tube 3 and an outer tube 4 made of, for example, quartz and having heat resistance and corrosion resistance are provided concentrically on the upper surface of the manifold 2, and the inner tube 3 and the outer tube 4 are used to form a vertical reaction tube having a double tube structure. 5 are configured. The inner tube 3 of the reaction tube 5 forms a processing space 6 and has an opening 2 of the manifold 2.
It is formed to have an inner diameter substantially equal to the inner diameter of “a”.

The outer tube 4 of the reaction tube 5 is formed with an inner diameter forming an annular exhaust passage 7 as an exhaust passage between itself and the inner tube 3. A resistance heating wire 8 is provided around the outer tube 4. A wound heating unit 9 is provided. The heating unit 9 is configured so that the temperature inside the reaction tube 5 can be raised at a rate of about 100 ° C./min by using, for example, molybdenum disilicide (MoSi ₂ ) as the resistance heating wire 8 and by forced air cooling means (not shown). The temperature can be lowered at about 50 ° C./min.

A stainless steel lid 12 provided on a lifting arm 11 of a lifting mechanism 10 is provided on the lower surface of the manifold 2 so as to be openable and closable. A wafer boat 14 that holds the wafers 13 in multiple stages at predetermined intervals is placed via a heat retaining tube 15. The lid 12 is provided with a rotation mechanism 16 for driving the heat retaining cylinder 15 to rotate. As shown in FIG.
O-rings 17a and 17b made of, for example, fluorine rubber having heat resistance and corrosion resistance for sealing between the upper surface peripheral portion of the manifold 2 and the lower surface portion of the manifold 2 are coaxially and doubly mounted via dovetail grooves 18. I have.

The manifold 2 is provided with a plurality of processing gas supply passages 19 penetrating in the radial direction in the circumferential direction. At the tip of these processing gas supply passages 19, the reaction tubes rise from the peripheral edge of the opening 2a of the manifold 2. A nozzle 20 for injecting and supplying a processing gas upward from below the inner pipe 3 of the tube 5 is connected, and a processing gas supply source (not shown) is connected to a base end of the processing gas supply passage 19. An exhaust pipe section 21 for exhausting the treated exhaust gas reaching the ceiling of the outer pipe 4 by lowering the exhaust pipe 7 of the inner pipe 3 and the outer pipe 4 is provided below the outer pipe 4 of the reaction pipe 5. The exhaust pipe section 21 is connected to a pressure reduction processing exhaust system 22 and a normal pressure processing exhaust system 23.
A valve 24, a vacuum pump 2
5, abatement equipment 26 and the like are provided in order,
3 has a valve 27 and a corrosive component (for example, HC) in the exhaust gas.
The processing device 28 of l) is provided in order.

On the other hand, the lower end of the inner tube 3 of the reaction tube 5 and the lower end of the outer tube 4 are separated, and the lower end of the inner tube 3 and the lower end of the outer tube 4 are connected to the upper surface of the manifold 2. , Outward flanges 3a and 4a are formed respectively. As shown in FIGS. 2 and 3, a positioning projection 29 surrounding the outer periphery of the flange 3 a of the inner pipe 3 directly mounted on the upper surface of the manifold 2 is formed on the upper surface of the manifold 2. On the outside, O-rings 30a and 30b made of, for example, fluoro rubber for sealing between the outer tube 4 and the flange 4a are doubly mounted concentrically via a dovetail groove 31.

On the outer surface of the O-rings 30a, 30b on the upper surface of the manifold 2, the horizontal movement of the outer circumference of the flange 4a of the outer tube 4 is regulated and the installation height position is defined, for example, by Teflon. A positioning ring 32 having an L-shaped cross section is attached, and a pressing member 33 for fixing the flange 4a of the outer tube 4 is attached to the outside of the positioning ring 32 by bolting.

In particular, the distal end of the flange 3a of the inner pipe 3 slightly overlaps the base of the flange of the outer pipe 4, so that the upper surface of the distal end of the flange 3a of the inner pipe 3 and the outer pipe 4 facing the upper end thereof. Between the bottom surface of the flange 4a and the bottom surface of the seal gas S
There is provided a predetermined gap 34 for jetting out.
As the seal gas S, for example, an inert gas such as a nitrogen (N ₂ ) gas, an argon (Ar) gas, and a helium (He) gas is preferable, and among them, a nitrogen (N ₂ ) gas is preferable.
Further, the sealing gas S is supplied from the gap 34 at a rate of 2 liters /
It is preferable that the ejection is performed at the quantile. The width of the gap 34 is preferably, for example, about 5 mm. On the flange 3 a of the inner pipe 3, a protrusion 35 is formed in a ring shape to direct the seal gas S ejected from the gap 34 upward,
A recess 36 is formed in an annular shape inside the projection 35.

The manifold 2 has a double O-ring space 17a, 17b on the upper end surface and a double O-ring
Pressure reduction passages 37a and 37b for reducing pressure between the rings 30a and 30b to obtain high sealing performance are formed, and a seal gas supply passage 38 for supplying the seal gas S to the gap 34 is formed. The pressure reducing passages 37a, 3
A pressure reducing source (not shown) such as a vacuum pump is connected to 7b.
A sealing gas supply source (not shown) is connected to the sealing gas supply passage 38. In addition, the manifold 2 has
A cooling water passage 39 for cooling the O-rings 17a, 17b, 30a, 30b and the like is provided.

Next, the operation of the above embodiment will be described. For example, when performing dry oxidation treatment under normal pressure using oxygen (O ₂ ) and hydrogen chloride (HCl) as processing gases, first, a reaction tube previously heated to a predetermined temperature (850 ° C.) by the heating unit 9 is used. 5, the wafer boat 14 holding the wafers 13 in multiple stages is loaded by the elevating mechanism 10 and the opening 2a of the manifold 2 is closed by the lid 12. In the case of the normal pressure treatment, there is no need to reduce the pressure between the O-rings 17a and 17b on the lid 12 and the manifold 2 and between the O-rings 30a and 30b.

Then, the normal-pressure exhaust system 23 is operated, and a gap 34 between the lower ends of the inner tube 3 and the outer tube 4 of the reaction tube 5 is formed.
Then, the processing gas is supplied from the nozzle 20 into the reaction tube 5 to start the heat treatment.
When the processing gas rises in the inner tube 4 of the reaction tube 5, the wafer 1
3 is subjected to uniform heat treatment in the plane, and the exhaust gas after the treatment descends through the exhaust passage 7 between the inner pipe 3 and the outer pipe 4, and is discharged from the lower exhaust pipe section 21 of the outer pipe 4 under normal pressure treatment. The air is exhausted to the system 23.

The exhaust gas is strongly corrosive due to the presence of moisture in hydrogen chloride (HCl). However, the gap 34 between the lower end of the inner tube 3 and the lower end of the outer tube 4 of the reaction tube 5 in contact with the manifold 2 is provided. Since the gap 34 is sealed by ejecting the seal gas S from the, the corrosive exhaust gas does not come into contact with the manifold 2. Therefore, corrosion of the manifold 2 due to corrosive exhaust gas can be prevented, and the durability of the manifold 2 can be improved. Some corrosive products not exhausted from the exhaust pipe portion 21 accumulate in the concave portion 36 inside the projection 35 on the flange 3a of the inner pipe 3, but the flange 3a of the inner pipe 3 has corrosion resistance. For example, since it is made of quartz, it does not corrode.

In the heat treatment apparatus, the upper surface of the front end of the flange 3a of the inner tube 3, which is a portion where the polishing can be performed with high mechanical precision and hardly undergoes thermal deformation, and the flange 4a of the outer tube 4 opposed thereto. The gap 34 for ejecting the seal gas S is formed between the bottom surface and the bottom surface of the base member, so that the width of the gap 34 does not easily change due to thermal deformation or the like, and the management of the gap 34 is easy. Further, in the reaction tube 5, since the lower ends of the inner tube 3 and the outer tube 4 are separated from each other, manufacturing, washing and handling are easy. Further, the manifold 2 is not provided with the exhaust pipe portion 21 and is formed in a flat ring shape, so that the structure can be simplified and downsized.

In the heat treatment apparatus, double O-rings 17a and 17b, 3b are provided between the manifold 2 and the lid 12 and between the manifold 2 and the outer tube 4 of the reaction tube 5.
0a and 30b, and O-rings 17a and 17b,
Since the pressure between 30a and 30b is reduced, a high sealing property is obtained. For example, after evacuation is performed to a high pressure of about 1 × 10 ⁻⁶ Torr, a CDV at a predetermined pressure, for example, 1 Torr is obtained.
Processing becomes possible. When performing the CDV processing, the depressurization processing exhaust system 22 may be operated. When performing oxidation, diffusion, and the like under normal pressure, the normal pressure processing exhaust system 23 may be operated as described above. Good.

As described above, since various heat treatments can be performed by one heat treatment apparatus 1, equipment costs can be reduced. Further, since the various heat treatments can be continuously performed in the same reaction tube 5 without transferring the wafer 13, the throughput can be improved. In this case, the throughput is further improved by using the heating unit 9 having a high temperature raising and lowering rate.

FIG. 4 is an enlarged sectional view of a main part showing another embodiment of the heat treatment apparatus according to the present invention, and the same parts as those of the above embodiment are denoted by the same reference numerals. Heat treatment apparatus 1 of this embodiment
, The seal gas S is not injected between the lower ends of the inner tube 3 and the outer tube 4 of the reaction tube 5, and instead, an O-ring is provided between the lower ends of the inner tube 3 and the outer tube 4. 40 is interposed.

In this case, unlike the heat treatment apparatus 1 of the above embodiment, a positioning projection 29 for the inner tube 3 and the inner O-ring 30b of the double O-rings 30a and 30b are provided on the manifold 2. Instead, an O-ring 40 made of, for example, fluoro rubber is disposed at the position where the positioning protrusion 29 was located. That is, the O-ring 40 is provided with a notch 41 provided on the manifold 2 at the tip of the flange 3a of the inner pipe 3 and on the lower surface of the base of the flange 4a of the outer pipe 4 so as to face the tip.
It is interposed between and.

According to the heat treatment apparatus of this embodiment configured as described above, substantially the same operation and effects as those of the heat treatment apparatus of the above embodiment can be obtained, but in particular, the inner tube 3 of the reaction tube 5 in contact with the manifold 2 and the outer tube An O-ring 4 is provided between the separated lower ends of the pipe 4.
Since the sealing is performed by zero, the manifold 2 can be prevented from being corroded with a simpler structure and at lower cost than the heat treatment apparatus of the embodiment using the sealing gas S.

The present invention is not limited to the above embodiment, and various modifications can be made within the scope of the present invention. For example, in the heat treatment apparatus of the above embodiment, since the processing gas is supplied from below to above, the exposed surfaces of the manifold 2 and the lid 12 exposed in the reaction tube 5 are corrosive. However, it is possible to provide a protective layer having heat resistance and corrosion resistance, for example, made of quartz, on the exposed surface. Further, as a material of the reaction tube 5, for example, sapphire, alumina, or the like can be applied in addition to quartz. Further, as the object to be processed, in addition to the semiconductor wafer, an LCD
And so on.

[0032]

In summary, according to the present invention, the following excellent effects can be obtained.

1) According to the first aspect of the present invention, the gap between the separated lower ends of the inner pipe and the outer pipe that are in contact with the manifold is sealed by the seal gas, so that the corrosion of the manifold caused by the contact of corrosive exhaust gas. Can be prevented, and the durability of the manifold can be improved.

2) According to the second aspect of the present invention, it is not necessary to form an exhaust pipe in the manifold, and the manifold can be formed flat, so that the structure of the manifold can be simplified and downsized.

3) According to the third aspect of the present invention, the gap between the separated lower ends of the inner pipe and the outer pipe that are in contact with the manifold is sealed by the seal member, so that the corrosion of the manifold caused by the contact of corrosive exhaust gas. Can be prevented with a simple structure and at low cost.

[Brief description of the drawings]

FIG. 1 is a sectional view showing one embodiment of a heat treatment apparatus according to the present invention.

FIG. 2 is an enlarged sectional view of a main part of the heat treatment apparatus of FIG.

FIG. 3 is a plan view of a manifold used in the heat treatment apparatus of FIG.

FIG. 4 is an enlarged sectional view of a main part showing another embodiment of the heat treatment apparatus according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat treatment apparatus 2 Manifold 3 Inner tube 4 Outer tube 5 Reaction tube 6 Processing space 7 Exhaust passage 9 Heating part 12 Lid body 13 Processing object (semiconductor wafer) S Seal gas 21 Exhaust pipe part 34 Gap 40 O ring

Claims (4)

(57) [Claims] An inner pipe and an outer pipe having heat resistance and corrosion resistance are provided concentrically on a metal manifold, and a processing gas is supplied from below to a workpiece contained in the inner pipe under a heated atmosphere. In a heat treatment apparatus in which exhaust gas after treatment is exhausted between the inner pipe and the outer pipe, a seal gas is ejected between a lower end of the inner pipe in contact with the manifold and a lower end of the outer pipe. A heat treatment apparatus, wherein a predetermined gap is provided. 2. The system according to claim 1, wherein the manifold is formed in a flat ring shape, and an exhaust pipe for exhausting exhaust gas is formed at a lower portion of the outer pipe. Heat treatment equipment. 3. An inner pipe and an outer pipe having heat resistance and corrosion resistance are provided concentrically on a metal manifold, and a processing gas is supplied from below to an object to be processed accommodated in the inner pipe under a heated atmosphere. In a heat treatment apparatus in which exhaust gas after treatment is exhausted between the inner pipe and the outer pipe, a gap is sealed between a lower end of the inner pipe in contact with the manifold and a lower end of the outer pipe. Heat treatment apparatus, characterized in that a sealing member is provided therebetween. 4. The sealing member according to claim 1, wherein said sealing member is made of an O
4. The heat treatment apparatus according to claim 3, wherein the heat treatment is performed.
Place.