JPH047834A - Heat treatment device for substrate - Google Patents

Abstract

PURPOSE:To prevent the outside air from intruding into a furnace core tube caused by the generation of a negative pressure by a method wherein an annular eccentric plate is mounted in a state that as the interval of a gap, which is formed between this annular eccentric plate and an inner side cylindrical body or an outer side cylindrical body, becomes nearer to an exhaust vent, the interval is made smaller. CONSTITUTION:A circular and annular baffle plate 13 having an eccentric opening 12 eccentric to the tube axis of a furnace core tube 1 is mounted on the outer peripheral surface of an inner side cylindrical body 7 between an exhaust vent 9 and an annular suction air port 20 in a space between the cylindrical body 7 and an outer side cylindrical body 8. In this case, the plate 13 is constituted into such a structure that it is mounted in a state that as the interval L between its outer peripheral surface and the inner peripheral surface of the cylindrical body 8 becomes nearer to the side of the vent 9, the interval L is made smaller, a large resistance is specially imparted to purge gas to be exhausted, which is near the side of the vent 9, and a suction exhaust force to act in open ends between the lower ends of the cylindrical bodies 7 and 8 is uniformized over the whole peripheries of the peripheral directions of the cylindrical bodies 7 and 8. Thereby, it is eliminated that gas which is exhausted from the interior of the tube 1 is one-sided to the side of the exhaust vent 9 and is exhausted, the generation of a negative pressure which accompanies the exhaust can be prevented and the outside air can be prevented from intruding into the tube 1.

Description

[Detailed Description of the Invention] <Industrial Application Field> The present invention applies various methods such as oxidation, annealing, CVD (chemical vapor deposition), or diffusion to various substrates such as semiconductor substrates and ceramic substrates. In order to perform heat treatment, a gas introduction hole is provided in a furnace core tube provided with a heating means around the periphery, and an opening for inserting and removing a substrate boat holding a substrate is provided at one end of the furnace core tube in the tube axis direction. The present invention relates to a heat treatment apparatus for substrates.

<Prior art> In this type of substrate heat treatment apparatus, when the substrate boat is inserted into or removed from the furnace core tube or when the substrate boat is pulled out,
If outside air enters the furnace core tube, it may cause the growth of natural oxide film on the substrates held in the substrate boat, for example, making it impossible to control the oxygen supply during heat treatment, or There is a problem in that impurities such as carbon dioxide gas adhere to the substrate, which adversely affects oxidation and CVD processes.

Therefore, conventionally, in order to prevent outside air from entering the furnace core tube, a purge gas made of an inert gas such as N2 gas is supplied into the furnace core tube, and at the same time, a purge gas made of an inert gas such as N2 gas is supplied to the opening side end of the furnace core tube. A suction/exhaust means called a scavenger is attached, and the scavenger suctions and exhausts the purge gas and outside air, thereby preventing outside air from entering the furnace core tube.

Note that the scavenger is a ring-shaped air intake that is provided with an inner cylinder at the open end of the furnace core tube for insertion and removal of the board boat, and that goes around the radial outside of the end of the inner cylinder that is far from the furnace core tube. An outer cylindrical body is provided on the outer periphery of the inner cylindrical body so as to form an opening, and an exhaust port is provided in the outer cylindrical body to communicate with an exhaust means to exhaust the space between the outer cylindrical body and the inner cylindrical body. This allows air to be taken in through a ring-shaped intake port.

<Problem to be solved by the invention> However, in the scavenger, that is, in the space between the inner cylinder and the outer cylinder, the suction and exhaust force is strong on the side closer to the exhaust port communicating with the exhaust means. , since it is weaker on the far side, the suction and exhaust force acting on the ring-shaped suction port in the scavenger is not constant in the circumferential direction.

For this reason, a strong (pulling) airflow is generated in which the purge gas is drawn towards the side of the ring-shaped suction port that is closer to the exhaust port.
Near the side of the ring-shaped suction port far from the exhaust port, a partial negative pressure state is created due to the airflow, and outside air flows in to compensate for this, preventing outside air from entering the furnace core tube. I wasn't able to stop it as much as I had hoped.

The present invention has been made in view of the above circumstances, and reduces the difference in the suction and exhaust force in the circumferential direction at the open end of the furnace core tube, thereby reducing the flow of outside air into the furnace core tube due to the generation of negative pressure. The purpose is to prevent intrusion.

Means for Solving the Problems> In order to achieve the above-mentioned object, the present invention, as the invention of claim (1), provides a method in which a gas introduction hole is provided in a furnace core tube around which a heating means is provided. At the same time, an opening for inserting and removing a substrate boat holding a substrate is provided at one end in the tube axis direction of the furnace core tube, an inner cylinder is provided at the open end of the furnace core tube, and an inner cylinder is provided at one end of the furnace core tube in the tube axis direction. An outer cylindrical body is provided on the outer periphery of the inner cylindrical body so as to form a ring-shaped intake port that goes around the radially outer side of the end farther from the inner cylindrical body, and an exhaust port is opened in the outer cylindrical body to communicate with the exhaust means. In a heat treatment apparatus for a substrate, in which air is taken in from a ring-shaped intake port by exhausting the space between the outer cylinder and the inner cylinder through the exhaust port, the space between the inner cylinder and the outer cylinder is In the space between the exhaust port and the ring-shaped intake port,
A ring-shaped eccentric plate having an eccentric outer edge or an inner edge is attached so that the gap formed between the ring-shaped eccentric plate and the inner cylinder or the outer cylinder becomes smaller as it approaches the exhaust port. .

Further, as the invention of claim (2), a gas introduction hole is provided in a furnace core tube provided with a heating means around the periphery, and a substrate boat holding a substrate is inserted into one end of the furnace core tube in the tube axis direction. An inner cylindrical body is provided at the opening side end of the furnace core tube, and a ring-shaped intake port is formed around the radially outer side of the end of the inner cylinder body that is far from the furnace core tube. An outer cylindrical body is provided on the outer periphery of the inner cylindrical body, an exhaust port is provided in the outer cylindrical body to communicate with the exhaust means, and the air between the outer cylindrical body and the inner cylindrical body is exhausted through the exhaust port. In a heat treatment apparatus for substrates in which air is taken in from a ring-shaped intake port, there is a gap between the exhaust port and the ring-shaped intake port in the space between the inner cylinder and the outer cylinder. By providing a first baffle plate that protrudes radially inward from the surface and a second baffle plate that protrudes radially outward from the outer peripheral surface of the inner cylinder body, The exhaust flow path toward the exhaust port is configured to be formed in a zigzag shape in the space between the outer cylindrical body and the exhaust port.

<Operation> According to the structure of the heat treatment apparatus for substrates according to the invention of claim (1), the outer circumferential surface of the baffle plate and the inner circumferential surface of the outer cylinder, or the inner circumferential surface of the baffle plate and the inner circumferential body The width of the exhaust flow path formed between the outer circumferential surfaces of the furnace tube is narrower on the side closer to the exhaust port, and the flow resistance given to the exhaust is larger on the side closer to the exhaust port, and The suction and exhaust force applied to the gas discharged from the furnace core tube can be made uniform over the entire circumference of the side.

Further, according to the structure of the substrate heat treatment apparatus according to the invention of claim (2), the baffle plate provides resistance to the suction and exhaust force acting through the exhaust port, and the baffle plate provides the suction and exhaust force in the circumferential direction. This makes it possible to prevent differences in the suction and exhaust force applied to the gas discharged from the furnace core tube over the entire circumference of the end farthest from the furnace core tube.

<Example> Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 1 is a longitudinal cross-sectional view of a first embodiment of the heat treatment apparatus for substrates, in which a furnace core tube l formed of a quartz material having infrared transmittance is provided so that the tube axis direction is directed in the vertical direction. A gas introduction hole 2 for supplying N2 gas as a purge gas and a reaction gas is provided at the upper end side in the tube axis direction of the furnace core tube 1, and on the other hand, a substrate W is held at the lower end side in the tube axis direction. An opening 4 for inserting and removing the board boat 3 is provided.

A purge gas supply means and a reaction gas supply means (not shown) are connected to the gas introduction hole 2 so as to be selectively communicable.

A heating means 5 is provided around the furnace core tube 1 and includes a first heater 5a that is short in the tube axis direction, a second heater 5b that is long, and a third heater 5c that is short.

A scavenger 6 is provided on the side of the opening 4 of the furnace core tube l, and when the substrate boat 3 is inserted into and removed from the furnace core tube 1 or when the substrate boat 3 is taken out from the furnace core tube 1 in an empty state, a scavenger 6 is installed on the side of the opening 4 of the furnace core tube l. It is configured to flow a purge gas made of an inert gas such as N2 gas, and to exhaust the purge gas from around the opening 4 together with the outside air that is about to enter the furnace core tube l.

The scavenger 6 includes an inner cylinder 7 provided at the end of the furnace core tube 1 on the side of the opening 4, and an outer cylinder 8 provided to cover it.
The space between the lower end of the inner cylinder body 7 and the lower end of the outer cylinder body 8 is open over the entire circumference, and a ring-shaped intake port 2 is formed.
0, and an exhaust port 9 is provided at the upper part of the outer cylindrical body 8 and is connected to an exhaust means (not shown).

Note that the outer cylinder 8 is composed of an outer cylinder main body member 8a and a partition plate 8b. The partition plate 8b doubles as a part of the plate material that separates the area where the furnace core tube 1 is installed and the area where the substrate boat 3 is extracted from the furnace core tube l and replaced with the substrate W, as shown by the imaginary line. It is something.

Further, an exhaust pipe 10 for exhausting a reaction gas, which is connected to an exhaust means (not shown) and is connected to an exhaust means (not shown), is provided so as to penetrate the inner and outer cylinders 7.8 and open inside the inner cylinder 7, and to hold the substrate W. When the substrate boat 3 is inserted into the furnace core tube 1 and a reactive gas such as pure oxygen is flowed through the gas introduction hole 2 with the opening 4 covered with the furnace mouth cap 11, the reactive gas is passed through the exhaust pipe 10. It is configured to be discharged.

Between the exhaust port 9 and the ring-shaped intake port 20 in the space between the inner cylinder 7 and the outer cylinder 8, that is, between the exhaust port 9 and the lower end of the inner cylinder 7 in this space, As shown in the enlarged vertical cross-sectional view of the main part in FIG. 2 and the cross-sectional view in FIG. 3 (partially cutaway view taken along the line ■-■ in FIG. A circular annular baffle plate 13 having an opening 12 eccentric with respect to the inner cylindrical body 7 is attached to the outer peripheral surface of the inner cylindrical body 7.

The baffle plate 13 is attached such that the distance between its outer peripheral surface and the inner peripheral surface of the outer cylindrical body 8 becomes smaller toward the exhaust port 9, and provides greater resistance to the exhausted purge gas toward the exhaust port 9. As a result, the suction and exhaust force acting at the open end between the lower ends of the inner cylinder body 7 and the outer cylinder body 8 is made uniform over the entire circumference in the circumferential direction.

Another embodiment of the baffle plate 13 is such that its outer diameter is approximately equal to the inner diameter of the outer cylinder 8 and the inner cylinder 7
It is configured by forming an opening having a larger diameter and eccentric to the tube axis of the furnace core tube 1, and attaching it to the outer cylindrical body 8, so that the distance between the inner circumferential surface of the baffle plate 13 and the inner cylindrical body 7 is It may be installed in such a manner that the distance becomes smaller toward the exhaust port 9 side.

The substrate boat 3B has three transparent pillars 3C made of quartz for supporting the substrate provided at intervals in the circumferential direction... quartz plates 3a and 3b are integrally mounted on both longitudinal ends thereof. It is set up and configured.

Each of the pillars 3C has substrate insertion grooves (not shown) formed at minute pitches in the longitudinal direction, and is configured such that the inner portion of the substrate W can be inserted and supported at three points.

On one side (lower side in the drawing) of the plate body 3a, there is a column 14.
A heat insulating support member 16 with a heat insulating plate 15 attached to...
is provided.

In the figure, reference numeral 17 indicates an elevating support arm, and by driving the elevating support arm 17 up and down, it holds the furnace opening cap 11 that closes the furnace opening, and lifts and lowers the substrate boat 3 supported on the furnace opening cap 11. It is configured so that it can be inserted into and removed from the furnace core tube 1.

Figure 4 is an enlarged vertical sectional view of the main part of the second embodiment, showing an exhaust port 9 and a ring-shaped intake port in the space between the inner cylinder 7 and the outer cylinder 8. 20, that is, between the exhaust port 9 and the lower end of the inner cylinder 7 in this space, an annular and equal width first baffle plate is provided on the inner peripheral surface of the outer cylinder 8 on the exhaust port 9 side. 13a
is attached, and a second annular baffle plate 13b having the same width is attached to the outer peripheral surface of the inner cylindrical body 7 on the lower side, and the inner diameter of the first baffle plate 13a is equal to the inner diameter of the inner cylindrical body 7.
is larger than the outer diameter of the second baffle plate 13b and smaller than the outer diameter of the second baffle plate 13b. This disperses the suction and exhaust force from the exhaust port 9 in the circumferential direction of the inner and outer cylinders 7 and 8, and further distributes the dispersed suction and exhaust force between the inner and outer cylinders 7 and 8 by the second baffle plate 13b. Suction and exhaust force can be applied over the entire circumferential length of the ring-shaped intake port 20 at the lower open end of the inner cylindrical body 7 in a state where it is distributed in the circumferential direction and there is no difference in the circumferential direction.

In this second embodiment, the baffle plate having the eccentric opening of the first embodiment described above may be used.

Next, the results of consideration regarding the exhaust flow based on the first embodiment described above will be explained.

The comparative example was based on the first embodiment without the baffle plate 13.

In both the first embodiment and the comparative example, N! is used as the purge gas from the gas introduction hole 2! gas at 1.2nf/
hour, the exhaust amount from the exhaust port 9 is 1. OnI/hou
It is set to flow at a rate of r, and the diameter of the inner peripheral surface of the furnace core tube l is set to 2.
An attempt was made to predict the profile of the velocity in hectors by simulation based on aerodynamic calculations.

FIG. 5 shows the profile at a location corresponding to the part indicated by line A-A in FIG. 3, where (a) shows the profile of the first example, and (b) shows the profile of the comparative example. Also,
FIG. 6 shows the profile at a location corresponding to the portion shown by line B-B in FIG. 3, where (a) shows the profile of the first example, and (b) shows the profile of the comparative example. FIG. 7 shows the profile at a location corresponding to the portion shown by line C-C in FIG. 3, with (a) showing the profile of the first example and (b) showing the profile of the comparative example. It shows.

In the above profile, at a location corresponding to the inside of the inner cylindrical body 7 connected to the inside of the furnace core tube 1, the exhaust speed is higher toward the lower side in the drawing. At a location corresponding to the outer peripheral surface and the inner peripheral surface of the outer cylindrical body 8, it is shown that the exhaust speed increases as it goes upward in the drawing.

From these results, in the comparative example, at the speed at a location corresponding to the outer circumferential surface of the inner cylinder 7 and the inner circumferential surface of the outer cylinder 8, the difference between the side closer to the exhaust port 9 and the side farther from the exhaust port 9 is determined. There is a large difference, and therefore the inner cylinder 7 on the far side from the exhaust port 9
Negative pressure is generated near the inner circumferential surface of the inner cylinder 7, and as shown in FIG. 6(b) and FIG. 7(b), the velocity at the part corresponding to the inside of the inner cylinder On the inner peripheral surface side of the furnace tube 7, the flow is inward in the opposite direction to the opening side, and outside air easily enters the furnace core tube 1. On the contrary,
In the first embodiment, there is no difference in speed between the outer peripheral surface of the inner cylinder 7 and the inner peripheral surface of the outer cylinder 8 over the entire length in the circumferential direction, and the inner cylinder 7 It was clear that the velocity at the portion corresponding to the inside of the furnace was an outward flow toward the opening side, and that the intrusion of outside air into the furnace core tube 1 could be effectively prevented.

In the above embodiment, a vertical type substrate heat treatment apparatus has been described, but the present invention can also be applied to a horizontal type substrate heat treatment apparatus.

Further, the position of the gas introduction hole 2 is not limited to the one provided at the end of the furnace core tube l opposite to the opening 4 in the tube axis direction.
It can also be applied to a type that is provided in the middle of the furnace core tube 1 in the tube axis direction.

<Effects of the Invention> As explained above, the heat treatment bag for substrates according to the invention of claim (1)! According to the above, by attaching a circular annular baffle plate having an opening eccentric to the tube axis of the furnace core tube to the inner circumferential surface of the outer cylinder or the outer circumferential surface of the inner cylinder in a predetermined posture, , on the entire circumference of the end far from the furnace core tube,
Since the suction and exhaust force applied to the gas discharged from the furnace core tube is made uniform, the exhaust is not biased towards the exhaust port side, preventing the generation of negative pressure due to exhaust, and reducing the flow of outside air into the furnace core tube. Invasion can be prevented, and during heat treatment, the amount of oxygen supplied can be appropriately controlled to perform oxidation and CVD processes favorably, improving quality and increasing product yield.

Moreover, the suction and exhaust force can be made uniform by simply providing a small number of baffle plates, making the structure simple.

Further, according to the substrate heat treatment apparatus according to the invention of claim (2), the suction and exhaust force is dispersed by the baffle plate, and the suction and exhaust force is dispersed from the inside of the furnace core tube around the entire circumference of the end side far from the furnace core tube. This suppresses the difference in the suction and exhaust force applied to the gas, which prevents exhaust from being concentrated toward the exhaust port, prevents the generation of negative pressure due to exhaust, and avoids the intake of outside air into the furnace core tube. During heat treatment, the amount of oxygen supplied can be appropriately controlled to perform oxidation and CVD processes favorably, thereby improving quality and increasing product yield.

[Brief explanation of drawings]

The drawings show an embodiment of the substrate heat treatment apparatus according to the present invention, FIG. 1 is a longitudinal sectional view of the first embodiment, FIG. 2 is an enlarged longitudinal sectional view of the main part, and FIG. ■■ Cotton wire - notch arrow view,
FIG. 4 is an enlarged longitudinal sectional view of the main part of the second embodiment, and FIGS. 5, 6, and 7 are diagrams showing velocity profiles of the exhaust flow in the first embodiment and the comparative example, respectively. 1...Furnace core tube 2...Gas introduction hole 3...
・Substrate boat 4...Opening 5...Heating means
7... Inner cylindrical body 8... Outer cylindrical body
9...Exhaust port 12...Eccentric opening 13...
Baffle plate 13a... First baffle plate 13b... Second baffle plate 20... Ring-shaped intake port L... Spacing R.
... Zigzag-shaped flow path W ... Substrate applicant Dainippon Screen Mfg. Co., Ltd. agent Patent attorney Sugitani
Figure (a) (b) Figure (a) (b) (a) Figure (b)

Claims (2)

[Claims] (1) A gas introduction hole is provided in a furnace core tube around which a heating means is provided, and an opening for inserting and removing a substrate boat holding a substrate is provided at one end of the furnace core tube in the tube axis direction, and the furnace core An inner cylindrical body is provided at the open end of the tube, and an inner cylindrical body is provided on the outer periphery of the inner cylindrical body so as to form a ring-shaped intake port that goes around the radially outer side of the end of the inner cylindrical body that is far from the furnace core tube. An outer cylindrical body is provided, an exhaust port is provided in the outer cylindrical body to communicate with the exhaust means, and the space between the outer cylindrical body and the inner cylindrical body is exhausted through the exhaust port, and air is discharged from the ring-shaped intake port. In a substrate heat treatment apparatus configured to take in air, a ring-shaped eccentric plate with an eccentric outer edge or an eccentric inner edge is disposed between an exhaust port and a ring-shaped intake port in a space between an inner cylinder and an outer cylinder. A heat treatment apparatus for substrates, characterized in that the ring-shaped eccentric plate is installed so that the gap formed between the inner cylinder or the outer cylinder becomes smaller as the side closer to the exhaust port approaches. (2) A gas introduction hole is provided in a furnace core tube provided with a heating means around the furnace core tube, and an opening for inserting and removing a substrate boat holding a substrate is provided at one end of the furnace core tube in the tube axis direction, and the furnace core An inner cylindrical body is provided at the open end of the tube, and an inner cylindrical body is provided on the outer periphery of the inner cylindrical body so as to form a ring-shaped intake port that goes around the radially outer side of the end of the inner cylindrical body that is far from the furnace core tube. An outer cylindrical body is provided, an exhaust port is provided in the outer cylindrical body to communicate with the exhaust means, and the space between the outer cylindrical body and the inner cylindrical body is exhausted through the exhaust port, and air is discharged from the ring-shaped intake port. In a heat treatment apparatus for substrates configured to take in air, the air is drawn radially inward from the inner peripheral surface of the outer cylinder between the exhaust port and the ring-shaped intake port in the space between the inner cylinder and the outer cylinder. By providing a first baffle plate that extends out and a second baffle plate that extends outward in the radial direction from the outer peripheral surface of the inner cylinder body to the first baffle plate, the space between the inner cylinder body and the outer cylinder body is reduced. A heat treatment apparatus for a substrate, characterized in that an exhaust flow path toward the exhaust port is formed in a zigzag-like flow path within the space.