JPH0982656A - Vertical heat-treating system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress the deterioration of O-rings when the part between the lower end flange part of a reaction tube and the upper end flange part of a manihold in a vertical heat-treating system is hermetically sealed via the O-rings. SOLUTION: In a reaction tube of a doulbe-tube structure, the lower end part of an outer tube 2 is slanted so that the diameter of the lower end part may become larger toward the lower end part, the lower end of the slanted part 5 is bent outward to form a flange part 51 and the part between this flange part 51 and an upper end flange part 13 of a manihold 1 is hermetically sealed via O-rings 10. By providing the slanted part 5, the optical path of light (heat rays) from such high-temperature parts as a wafer boat 33 and a heat insulating cylinder 32 is decreased in a quartz (in the lower end part of the outer tube 2) and the amount of the heat rays to reach the O-rings 10 is decreased. Moreover, radiant heat shielding members 6 and 7 are respectively provided on the inward side of the slanted part 5 and the upper surface side of the flange part 51, whereby the amount of the heat rays to reach the O-rings is more suppressed.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a vertical heat treatment apparatus.

[0002]

2. Description of the Related Art As one of semiconductor manufacturing apparatuses, a large number of semiconductor wafers (hereinafter referred to as "wafers") are held in a shelf on a wafer boat and are collectively subjected to a CVD (Chemical Vap).
There is a vertical heat treatment apparatus for performing heat treatment such as or Deposition). FIG. 9 shows a conventional structure of an apparatus for performing low-pressure CVD in this heat treatment apparatus. Reference numeral 1 denotes a cylindrical manifold, and a manifold made of a quartz outer tube 2 and an inner tube 3 is provided on the manifold 1. A reaction tube 20 having a tubular structure is attached. A heating furnace 4 is provided around the reaction tube 20 so as to surround the reaction tube 20. A gas supply pipe 11 for supplying a processing gas is provided between the outer pipe 2 and the inner pipe 3 in the manifold 1, and an exhaust pipe 12 is connected to the gas supply pipe 11.

The lower end of the outer tube 2 is bent outward at a right angle to form a flange portion 21.
And the flange portion 13 at the upper end of the manifold 1 are airtightly joined to each other via an O-ring 10 which is a sealing member. The lower end opening of the manifold 1 is hermetically closed by a cap 31 via an O-ring 30 when a wafer is loaded, and a wafer boat 33 is provided on the cap 31 via a heat retaining cylinder 32. A large number of wafers W are loaded in a shelf shape on the wafer boat 33. These wafers W are heated to a predetermined temperature by the radiant heat of the heating furnace 4, and are subjected to CVD with a processing gas in a reduced pressure atmosphere to form a wafer W on the surface. Be filmed.

The O-ring 10 that seals between the outer tube 2 and the manifold 1 radiates heat from the high-temperature parts such as the wafer boat 33, the wafer W, and the heat insulating cylinder, and the heat conduction from the outer tube 2 and the manifold 1. It will be heated by and will deteriorate immediately if left as it is. Therefore, a method of flowing cooling water into the flange portion 13 of the manifold 1 or the outer pipe 2 as described in Japanese Utility Model Publication No. 6-38113
There is known a method in which cooling water is caused to flow through a pressing member that holds the flange portion 21 of the O-ring 10 to suppress deterioration of the O-ring 10.

[0005]

The cooling water functions to suppress heat conduction from the outer pipe 2 and the manifold 1, but O
Since the ring 10 receives heat radiation from the high temperature part, so-called sunburn phenomenon may cause seizure on the surface, which is not a sufficient method for preventing deterioration of the O-ring 10. If the cooling is relied too much, the product adheres to the lower end portion of the outer tube 2 and the inner surface of the manifold 1 to increase the frequency of maintenance. Furthermore, it is very difficult to control the cooling water so as not to overcool it and to extend the life of the O-ring, because the treatment temperature varies depending on the type of treatment.

The present invention has been made under such circumstances, and an object thereof is a vertical member which can prolong the service life of a sealing member such as an O-ring for sealing between a reaction tube and a manifold. To provide a mold heat treatment apparatus.

[0007]

According to a first aspect of the present invention, there is provided an upper end flange portion of a manifold provided with a processing gas supply pipe and an exhaust pipe and a lower end flange portion of a reaction pipe provided in a heating furnace. In a vertical heat treatment apparatus that is airtightly bonded via a seal member, holds a substrate to be processed in a holder, and carries it into a reaction tube through a lower end opening of the manifold, at least the lower end of the reaction tube. It is characterized in that the inner surface is provided with at least a part of an inclined portion whose diameter increases as it goes downward.

According to a second aspect of the present invention, the upper flange portion of the manifold provided with the processing gas supply pipe and the exhaust pipe and the lower flange portion of the reaction pipe provided in the heating furnace are interposed by a seal member. In a vertical heat treatment apparatus in which a substrate to be processed is held in a holder and carried into the reaction tube through the lower end opening of the manifold, the reaction is performed on the inner side of the inner surface of the lower end of the reaction tube. A radiant heat shield member for shielding radiant heat radiated from the inner side of the pipe to the flange portion is provided.

According to the third aspect of the present invention, the upper flange portion of the manifold provided with the processing gas supply pipe and the exhaust pipe and the lower flange portion of the reaction pipe provided in the heating furnace are interposed by a seal member. In a vertical heat treatment apparatus in which the substrate to be processed is held in a holder and carried into the reaction tube through the lower end opening of the manifold, the inner surface of the lower end of the reaction tube is reduced in diameter as it goes downward. And a radiant heat shield member for shielding radiant heat radiated from the inner side of the reaction tube to the flange portion on the inner side of the inclined portion.

The invention of claim 4 is the invention of claim 1, 2 or 3.
In the present invention, the upper surface of the lower end flange portion of the reaction tube is inclined so as to become lower as it goes downward.

The invention of claim 5 is characterized in that, in the invention of claim 1, 2, 3 or 4, a radiant heat shield member is provided so as to cover the upper surface of the lower end flange portion of the reaction tube.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION An example of an embodiment of the present invention will be described with reference to FIGS. In the figure, the same reference numerals as those in FIG. 8 denote the same parts. Reference numeral 1 denotes, for example, a tubular manifold made of stainless steel.
The upper end portion of the is bent outward to form a flange portion 13, and the flange portion 13 supports the lower end of the outer tube 2 made of quartz. The outer tube 2 is formed of a bottomed cylindrical body with the opening side facing downward, and the inclined portion 5 is provided so that the diameter of the lower end wall of the outer tube 2 increases toward the lower side. A flange portion 51 bent outward is formed at the lower end of the inclined portion 5, and both flange portions 13,
The 51 are hermetically joined by a seal member such as an O-ring 10 made of Viton or silicon rubber.

A cooling water passage 14 is formed in the flange portion 13 of the manifold 1 in the vicinity of the O-ring 10 as shown in FIG. The ring 10 is cooled. A cylindrical first radiant heat shield member 6 supported by the upper surface of the inner peripheral edge portion of the flange portion 13 is provided on the inner side of the inclined portion 5 of the outer tube 2. The radiant heat shield member 6 has a role of preventing the radiant heat from entering the radiant O-ring 10 from the heater 42, and is formed in a ring shape so as to face the entire inner circumference of the inclined portion 5. .

The upper surface of the flange portion 51 on the outer pipe 2 side is pressed by a holding member 7 having a key-shaped (reverse L-shaped) cross section, which is provided near the outer edge portion of the flange portion 13 of the manifold 1. As shown in the enlarged view of FIG.
Is a bolt 71 penetrating from the lower surface side of the flange portion 13.
Is tightened to the flange portion 13 side, so that the flange portion 51 is narrowed between itself and the flange portion 13. The holding member 7 corresponds to a second radiant heat shield member in this example, and also has a role of preventing radiant heat from the heater 42 from entering the O-ring 10 from above and outside. ing. A base plate 72 is provided on the pressing member 7.

On the other hand, the diameter of the lower side of the manifold 1 is smaller than that of the upper side, and the step portion at the boundary supports the lower end of a cylindrical inner tube 3 made of, for example, quartz and having both openings. The outer tube 2 and the inner tube 3 form a reaction tube 20,
(That is, the reaction tube 20 is a double tube.) A heating furnace constituted by disposing a heater composed of a resistance heating wire 42 on the inner peripheral surface of a heat insulating member 41 around the reaction tube 20. 4 are provided. A gas supply pipe 11 for supplying a processing gas is provided between the outer pipe 2 and the inner pipe 3 through the manifold 1, and an exhaust pipe 12 having a flat connection port is connected to the manifold 1.

The lower end opening of the manifold 1 is hermetically closed by a cap 31 via an O-ring 30 when a wafer is loaded, and a wafer boat 33 is provided on the cap 31 via a heat retaining cylinder 32. There is. The wafer boat 33 has four pillars made of, for example, quartz, and ring-shaped wafer holders arranged in a shelf shape.
The cap 31 is mounted on the boat elevator 34.

Next, the operation of this embodiment will be described. First, in the lower region of the reaction tube 20, the wafer boat 3
The wafer W is mounted on the wafer No. 3, and the boat elevator 34 is lifted and loaded into the reaction tube 20 through the lower end opening of the manifold 1. At this time, the lower end opening of the manifold 1 is hermetically closed by the cap 31. The inside of the reaction tube 20 is heated to a predetermined temperature by the heater 42 of the heating furnace 4, for example, 600
While heating to around ℃, the reaction tube 20 from the exhaust pipe 12
A processing gas such as a silane gas is supplied from the gas supply pipe 11 while the inside of the wafer is under a predetermined reduced pressure atmosphere to form, for example, a polysilicon film on the wafer W.

Here, the lower end side of the outer tube 2 which is a main part of the present invention will be described. The wafer boat 33 by the heater 42,
The wafer W and the heat retaining tube 32 are heated to the processing temperature, and the high temperature portion serves as a radiant heat source to radiate heat rays to the lower end portion of the outer tube 2. The first radiant heat shield member 6 has a flange portion 13,
It plays a role of blocking heat rays (radiant heat) incident at a low angle when viewed from the O-ring 10 at the joint portion of 51. Further, the second radiant heat shield member 6 plays a role of blocking heat rays which are incident at a high angle as viewed from the O-ring 10, that is, heat rays which are about to be incident on the upper surface of the flange portion 51.

The heat ray from the high temperature portion enters the quartz portion (tube wall portion and flange portion) of the outer tube 2 and either exits to the manifold 1 side as it is or reflects inside the quartz and exits to the outside. The relationship between these heat rays and the O-ring 10 will be described later based on the simulation result. When the lower end portion of the outer tube 2 is vertical, the amount of heat rays reaching the O-ring 10 through the quartz portion is Many,
When the lower end portion of the outer tube 2 is inclined, the light path is reduced, and as a result, the amount of heat rays reaching the O-ring 10 is reduced while the thickness of the flange portion 51 is sufficiently large in terms of strength.

Since the lower end of the outer tube 2 is inclined and the first and second radiant heat shield members 6 and 7 are provided in this manner, the amount of heat rays reaching the O-ring 10 is reduced, so that the O-ring 10 is reduced. It is possible to suppress the seizure of and to prolong the service life. The heat transfer from the flange portion 13 to the O-ring 10 is suppressed by the flow of cooling water.

In the present invention, the lower end portion of the outer tube 2 may be made vertical as in the conventional case without being inclined, and the first radiant heat shield member 6 may be provided on the inner side thereof, but the inclined portion may be provided. Forming 5 and providing the radiant heat shield member 6 on the inner side thereof is advantageous because it is not necessary to increase the diameter of the outer tube 2. That is, when the inclined portion 5 is not provided, the manifold 1
When the radiant heat shield member 6 is provided on the flange portion 13 of
It is necessary to increase the pipe diameter of the outer pipe 2, and conversely, if the pipe diameter is the same as the conventional one, the structure on the inner surface side of the manifold 6 becomes complicated.

Here, the result of a computer simulation conducted to examine how the amount of heat rays reaching the O-ring 10 differs between the case where the lower end of the outer tube 2 is tilted and the case where it is not tilted. Describe.
FIG. 3 is a diagram showing a target of the simulation.
3A shows a structure in which the lower end of the outer tube 2 is vertical, and FIG. 3B shows a structure in which the lower end of the outer tube 2 is inclined. The shaded area is the first radiant heat shield member.

In the structure shown in FIG. 3, the wafer boat 33
4 (a) to (c), and FIG. 4 (a) to FIG. 4 (c), showing the optical paths of the respective lights when light is emitted to the lower end portion of the outer tube 2 from the set point of the upper region of the Figure 5 (a)
~ (C). However, the refractive index of quartz is 1.4
68, the optical path from the above point is changed at intervals of 1 °.

As shown in FIGS. 4 (a) and 5 (a), 4 (b) and 5 (b), the upper region of the wafer boat,
Regarding the light reaching the lower end of the outer tube 2 from the upper region of the heat insulating tube, the amount of light reaching the position of the O-ring (in this example, about 30 mm in the X direction position) is higher when the inclined portion is provided. You can see that there are few. And for the light emitted from the low-angle region as seen from the O-ring, FIG.
As shown in FIG. 5C, it can be seen that the difference is particularly remarkable. Therefore, from this simulation result, the outer tube 2
It is proved that the method of inclining the lower end of the is effective in suppressing the seizure of the O-ring.

Further, in the present invention, the upper surface of the flange portion 21 of the outer tube 2 may be inclined so that it becomes lower toward the outer side. FIG. 7 is a diagram showing the cross-sectional view of such an embodiment and the simulation result of the optical path in association with each other. Looking at the light emitted in different directions from the point P, the light reaches the O-ring 10. It can be seen that the amount of light emitted is small. FIGS. 7A and 7B are diagrams showing simulation results in which the optical paths of the light from the point P are examined for the case where the upper surface of the flange portion 21 is horizontal and the case where the upper surface is inclined, respectively. From this, it is understood that it is advantageous to incline the upper surface of the flange portion 21.

The heat treatment apparatus to which the present invention is applied is not limited to a reaction tube having a double structure, but may be a single reaction tube. Further, as shown in FIG. When inclining, the outer surface side may be vertical and only the inner surface side may be inclined.

[0027]

As described above, according to the present invention, it is possible to suppress the seizure of a sealing member, such as an O-ring, for hermetically sealing the lower end of the reaction tube and the upper end of the manifold.

[Brief description of drawings]

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

FIG. 2 is a cross-sectional view showing a lower structure of a reaction tube in the embodiment of the present invention.

FIG. 3 is a schematic diagram in the vicinity of a lower portion of a reaction tube which is a target of a simulation for examining an optical path.

FIG. 4 is an explanatory diagram showing a result of simulating an optical path in a comparative structure.

FIG. 5 is an explanatory diagram showing a result of simulating an optical path in the structure of the present invention.

FIG. 6 is an explanatory diagram correspondingly showing a lower structure of a reaction tube and a simulation result of an optical path according to another embodiment of the present invention.

FIG. 7 is an explanatory diagram showing the results of simulating the optical paths of the case where the upper surface of the flange portion of the reaction tube is horizontal and the case where the upper surface is inclined.

FIG. 8 is a cross-sectional view showing a lower structure of a reaction tube according to still another embodiment of the present invention.

FIG. 9 is a cross-sectional view showing a conventional vertical heat treatment apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Manifold 10 O-ring 13 Flange part 14 Cooling water passage 20 Reaction tube 2 Outer tube 3 Inner tube 31 Cap 32 Heat retaining tube 33 Wafer boat W Semiconductor wafer 4 Heating furnace 5 Inclined part 51 Flange part 6 First radiant heat shield member 7 Second radiant heat shield member

Claims (5)

[Claims] 1. An upper end flange portion of a manifold provided with a processing gas supply pipe and an exhaust pipe and a lower end flange portion of a reaction tube provided in a heating furnace are hermetically joined to each other via a seal member. In a vertical heat treatment apparatus for holding a substrate to be processed in a holder and carrying it into a reaction tube through a lower end opening of the manifold, a diameter increases toward at least an inner surface of the lower end of the reaction tube as it goes downward. A vertical heat treatment apparatus having at least a part of an inclined portion. 2. An upper end flange portion of a manifold provided with a processing gas supply pipe and an exhaust pipe and a lower end flange portion of a reaction pipe provided in a heating furnace are hermetically joined to each other via a seal member. In a vertical heat treatment apparatus for holding a substrate to be processed in a holder and carrying it into the reaction tube from the lower end opening of the manifold, an inner side of the inner surface of the lower end of the reaction tube and an inner side of the reaction tube. A vertical heat treatment apparatus comprising a radiant heat shield member for shielding radiant heat radiated from the above to the lower end flange portion. 3. An upper end flange portion of a manifold provided with a processing gas supply pipe and an exhaust pipe and a lower end flange portion of a reaction tube provided in a heating furnace are hermetically joined via a seal member. In a vertical heat treatment apparatus which holds a substrate to be processed in a holder and carries it into a reaction tube through a lower end opening of the manifold, an inner surface of the lower end of the reaction tube is increased in diameter as it goes downward. Incline and on the inner side of the inclined part,
A vertical heat treatment apparatus provided with a radiant heat shield member for shielding radiant heat radiated from the inner side of the reaction tube to the lower end flange portion. 4. The vertical heat treatment apparatus according to claim 1, wherein the upper surface of the lower end flange portion of the reaction tube is inclined so as to become lower as it goes downward. 5. The vertical heat treatment apparatus according to claim 1, wherein a radiant heat shield member is provided so as to cover the upper surface of the lower end flange portion of the reaction tube.