JP2000323485A - Heating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve uniformity in heating and productivity of a heating device. SOLUTION: A heating device includes a vertical cylindrical heater box 2 with a closed top and an open bottom so as to cover a body to be heated 1 from above and a heater 2a placed on its inside, a bottom heater 2b disposed under the bottom end of the heater box 2 with a small distance between them and heating the body 1 from below, a vertical cylindrical shield box 5 with an open bottom and a closed top so as to cover the heater box 2 from above, a vertical cylindrical closed box 3 with a bottom to be opened for receiving these members, and a lid 6 closing the holes and moving up and down. Holes 2c, 5a are made concentrically in the heater box 2 and the shield box 5. When the lid 6 is at the lowest position, the hold 2c is closed, when the lid is at the middle position, the hole 2c is opened and the hole 5a is closed, and when the lid 6 is at the highest position, both holes 2c, 5a are opened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a heating apparatus used for heat treatment of a semiconductor material such as a glass substrate, a processing material, and the like, and more particularly to a heating apparatus for heating under pressure.

[0002]

2. Description of the Related Art Annealing furnaces, diffusion furnaces, and oxidizing furnaces for processing semiconductor films formed on silicon wafers and substrates, and low-pressure CVD (chemical vapor deposition) for forming films.
)) has been widely used in the past. In recent years, the mainstream of these heating furnaces is a type in which a reaction tube is placed vertically instead of a type in which a reaction tube is placed horizontally (for example, disclosed in FIG. 3 of JP-A-8-8194) in order to save space in the apparatus. Has become. In the oxidation furnace, a high reaction rate depending on the pressure can be obtained by increasing the pressure of the gas atmosphere in the reaction vessel (for example, disclosed in JP-A-53-112064 and JP-A-56-24938). .) Is also known. In recent years, since a large-area square glass substrate is used for a liquid crystal display or the like, an apparatus for processing a large-area square glass substrate instead of a conventional round silicon wafer is required.

FIG. 4 is a sectional view of a conventional heating device. In the figure, reference numeral 1 denotes an object to be heated such as a processing material. In addition,
When introducing a reaction gas during heating in an oxidation furnace or the like, the object to be heated is housed in a sealed reaction vessel made of quartz or the like to prevent internal contamination, and the reaction gas is introduced into the reaction vessel. When the pressure of the reaction gas is increased, high-pressure air is introduced outside the reaction vessel to equalize the pressure inside and outside the reaction vessel.

[0004] Reference numeral 2 denotes a heater container which surrounds the object 1 so as to cover the object to be heated 1 from above, has a lower part opened, and a closed upper part, and has a heater 2a adhered to the inner surface thereof. Reference numeral 2b denotes a lower heater, which is provided slightly below and below the lower end of the heater container 2 so as to heat the object 1 to be heated from below, and has a heater 2a embedded in the upper surface.
Numeral 3 denotes a closed container, which is a vertical cylinder and comprises an upper container 3a and a lower container 3b, which are connected by a flange 3c, and which can be opened for taking in and out the object 1 to be heated. 3d is a seal such as an O-ring. Reference numeral 4 denotes a cooling jacket attached to the outer surface of the closed container 3. A gas at 1 to 50 atm can be sealed in the closed container.

[0005] A method of heating an object to be heated by this heating apparatus and performing heat treatment will be described. The sealed container 3 is opened, the object 1 to be heated is inserted, the container is closed again, and heating is started by the heater 2a. After the temperature inside the heating device is increased to a predetermined heat treatment temperature, for example, 600 ° C., the heat treatment is performed while maintaining the temperature for a predetermined time. When the heat treatment is completed, water is passed through the cooling jacket 4 to cool it naturally. For example, when the inside is cooled to about 200 ° C., the water flow is stopped, the closed vessel 3 is opened, and the object to be heated 1 is taken out of the apparatus.

[0006]

The object to be heated 1
It is necessary to maintain a constant temperature for a predetermined time in order to perform the heat treatment. However, the high-temperature gas is light inside the heater container 2,
Since the low-temperature gas is collected at the upper portion of the heater container 1 and the low-temperature gas is heavily collected at the lower portion of the heater container, the object to be heated cannot be equalized in temperature. Further, it takes a long time to cool from the heat treatment temperature to the temperature at which the article 1 to be heated is taken out because heat is hardly generated due to convection and heat is released due to heat transfer, and the heat treatment cycle becomes longer and productivity is reduced. .

The present invention has been devised in view of the above-mentioned problems of the conventional heating apparatus, and aims to improve the quality by improving the uniformity of the object to be heated, and to improve the productivity by shortening the cooling time. It is an object of the present invention to provide a heat treatment apparatus that can perform the heat treatment.

[0008]

Means for Solving the Problems To achieve the above object, a heating apparatus according to the present invention surrounds an object to be heated so as to cover the object to be heated from above, and has a vertical cylindrical shape in which a lower part is opened and an upper part is closed. A heater container to which a heater is attached, a lower heater provided slightly below the lower end of the heater container to heat the object to be heated from below, and a lower portion surrounding the heater container so as to cover the heater container from above; A heating device comprising: a vertical cylindrical shielded container which is open and the top is closed; and a vertical cylindrical closed container capable of opening the bottom and housing the heater container and the shield. Holes are formed concentrically at the center of the ceiling of the container, and a lid that can be moved up and down to close those holes is provided.When the lid is at the lowest position, the holes in the heater container are closed. And
When the lid is in the middle position, the hole in the heater container is open and the hole in the shield container is closed, and when the lid is at the uppermost position, both the hole in the heater container and the hole in the shield container are open. ing.

It is preferable that a gas at 1 to 50 atm is sealed in the closed container, because the heat treatment time can be shortened.

[0010] A cooling jacket is preferably attached to the outer surface of the closed vessel.

Hereinafter, the operation of the present invention will be described. The sealed container is opened, an object to be heated is inserted, the container is closed again, and heating is started by the heater. The temperature inside the heating device is raised to a predetermined heat treatment temperature. During this time, the lid is at the lowermost position and the hole of the heater container is closed. Therefore, convection hardly occurs in the heating device, and the amount of heat radiation is small, so that the temperature rises quickly.

When a predetermined heat treatment temperature is reached, heat treatment is performed while maintaining the temperature for a predetermined time. The lid is in the middle position, the hole in the heater container is open, and the hole in the shield container is closed. In the heater container, the heated high-temperature gas rises in the heater container and flows out through the hole of the heater container. Since the temperature of the sealed container outside the shield container is low, the temperature of the shield container is also lower than the inside of the heater container, and the high-temperature gas flowing out of the heater container is cooled, and the gap between the heater container outside and the shield container inside is reduced. It descends, flows into the heater container again from the lower end of the heater container, is heated in the heater container, and rises. Since the convection is performed in this manner, the temperature inside the heater container can be equalized without having a high temperature in the upper portion and a low temperature in the lower portion as in the conventional heating device.

When the heat treatment is completed, the heater is turned off, and water is passed through a cooling jacket attached to the outer surface of the closed vessel. The lid is at the uppermost position, and the hole in the heater container and the hole in the shield container are both open. The gas heated by the object to be heated in the heater container rises in the heater container and flows out of the heater container through the hole. Part of the gas flowing out of the heater container descends through the gap between the outside of the heater container and the inside of the shield container, and the remainder flows out of the hole of the shield container to the outside. The gas that has flowed out of the shield container is cooled there because the inner surface of the closed container is cooled by the cooling jacket, and descends through the gap between the outer surface of the shield container and the inner surface of the closed container. The low-temperature gas that has flowed down the gap between the inner surface and the outer surface of the shield container flows into the heater container from the lower end of the heater container, raises the temperature while cooling the object to be heated, and rises in the heater container. Since the convection is performed as described above, the object to be heated is rapidly cooled.

In accordance with the change of the position of the lid in the three stages of the lowermost position, the intermediate position, and the uppermost position, the object to be heated is heated, soaked, and cooled. And the productivity can be improved by shortening the heating and cooling times.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 is a cross-sectional view of the heating device of the present invention, showing a state where a lid is at a lowermost position. FIG. 2 is a similar cross-sectional view showing the state where the lid is at an intermediate position. FIG. 3 is a similar sectional view showing a state where the lid is at the uppermost position. In these figures, the same reference numerals are given to the same parts as those of the conventional heating device shown in FIG. 4, and duplicate description will be omitted. In these figures, reference numeral 1 denotes an object to be heated. Reference numeral 2 denotes a heater container, which is a vertical cylindrical shape which surrounds the object to be heated 1 so as to cover it from above, has a lower portion opened and an upper portion sealed, and has a heater 2a attached to an inner surface thereof. Reference numeral 2b denotes a lower heater, which is provided slightly below the lower end of the heater container 2 and has a heater 2a on the upper surface to heat the object 1 to be heated. Reference numeral 5 denotes a shield container, which has a vertical cylindrical shape that surrounds the heater container 2 so as to cover the heater container 2 from above, and has an open lower portion and a closed upper portion. Reference numeral 3 denotes a closed container, and the heater container 2,
It houses the lower heater 2b, the shield container 5, and the like,
It has a vertical cylindrical shape. The closed container 3 includes an upper container 3a and a lower container 3b.
c, and can be opened for taking in and out of the object 1 to be heated. A cooling jacket 4 is attached to the outer surface of the closed container 3.

Reference numeral 2c denotes a hole formed in the center of the ceiling of the heater container 2, and reference numeral 5a denotes a hole formed in the center of the ceiling of the shield container 5, which is vertically and concentrically formed. 5b is a support connecting the heater container 2 and the shield container 5. Reference numeral 6 denotes a lid, which is fixed to a lower end of a rod 6b connected to a piston rod of an air cylinder 6a. The rod 6b penetrates a hole 3e formed in the center of the ceiling of the upper container 3a of the closed container 3 so as to be slidable up and down. 3f is a seal. The lid 6 is moved up and down by an air cylinder 6a. When the lid 6 is at the lowermost position, the hole 2 of the heater container 2
c is closed, and when the lid 6 is at the intermediate position, it opens to the hole 2c of the heater container 2, and when the lid 6 is at the uppermost position, the hole 5a of the shield container 5 is closed. The hole 2c and the hole 5a of the shield container 5 are both open.

The operation of this embodiment will be described below. The sealed container 3 is opened, the object to be heated is inserted, the container is closed again, and heating is started by the heater 2a. The temperature inside the heating device is raised to a predetermined heat treatment temperature. The lid 6 is located at the lowermost position as shown in FIG. 1, and the hole 2c of the heater container 2 is closed.
Therefore, convection hardly occurs in the heating device, and the amount of heat radiation is small, so that the temperature rises quickly.

When a predetermined heat treatment temperature is reached, the heat treatment is performed while maintaining the temperature for a predetermined time. As shown in FIG. 2, the lid 6 is located at an intermediate position, the hole 2c of the heater container 2 is opened, and the hole 5a of the shield container 5 is closed. In the heater container 2, the heated high-temperature gas rises in the heater container 2 as indicated by an arrow, and flows out through the hole 2 c of the heater container 2. Closed container 3 outside shield container 5
Is low, the temperature of the shield container 5 is also lower than that of the inside of the heater container 2, and the high-temperature gas flowing out of the heater container 2 is cooled and descends through the gap 7 between the outside of the heater container 2 and the inside of the shield container 5. Then, it flows into the heater container 2 again from the lower end of the heater container 2 and is heated in the heater container 2 and rises. As described above, since the convection is performed, the temperature in the heater container 2 does not become high in the upper part and low in the lower part as in the conventional heating device, and the uniform temperature can be achieved.

When the heat treatment is completed, the heater 2a is turned off, and water is passed through the cooling jacket 4 attached to the outer surface of the closed vessel 3. The lid 6 is at the uppermost position as shown in FIG. 3, and the hole 2c of the heater container 2 and the hole 5a of the shield container 5 are both open. The gas heated by the object to be heated in the heater container 2 rises in the heater container 2 and flows out of the hole 2c of the heater container 2 to the outside. Part of the gas flowing out of the heater container 2 is generated by a gap 7 between the outside of the heater container 2 and the inside of the shield container 5.
And the remainder flows out of the hole 5c of the shield container 5 to the outside. The gas flowing out of the shield container 5 is
Since the inner surface is cooled by the cooling jacket 4, it is cooled there, and descends through the gap 8 between the outer surface of the shield container 5 and the inner surface of the closed container 3. The low-temperature gas that has flowed down the gaps 7 and 8 between the inner surface and the outer surface of the shield container 5 flows into the heater container 2 from the lower end of the heater container 2, raises the temperature while cooling the object to be heated, and rises inside the heater container 2. . Since the convection is performed as described above, the article to be heated 1 is rapidly cooled.

As described above, the temperature of the object to be heated is increased, soaked, and cooled in response to the change of the position of the lid 6 to the lowermost position, the intermediate position, and the uppermost position. It is possible to improve the quality by thermalization and the productivity by shortening the heating time and the cooling time.

The present invention is not limited to the embodiments described above, and various changes can be made without departing from the gist of the invention. For example, when introducing a reaction gas during heat treatment such as in an oxidation furnace, the object to be heated may be housed in a closed reaction vessel, and the reaction gas may be introduced into the reaction vessel. Further, although the ceiling and the bottom of the closed container are drawn as disks in the figure, it is preferable that the container is dish-shaped in order to form a high-pressure container.

[0022]

As described above, in the heating device of the present invention, the shield container is provided outside the heater container, holes are formed in the center of the ceiling of the heater container and the shield container, and the holes are formed by the lid which can be raised and lowered. Either one of them is closed or both are opened, so that the quality of the material to be heated during heat treatment is improved and quality is improved, and the temperature rise and cooling are performed rapidly to shorten the cycle time of heat treatment. And has excellent effects such as improvement in the productivity of the heating device.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a heating device of the present invention, showing a state where a lid is at a lowermost position.

FIG. 2 is a cross-sectional view of the heating device of the present invention, showing a state where a lid is at an intermediate position.

FIG. 3 is a cross-sectional view of the heating device of the present invention, showing a state where a lid is at an uppermost position.

FIG. 4 is a sectional view of a conventional heating device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heated object 2 Heater container 2a Heater 2b Lower heater 2c Hole 3 Airtight container 4 Cooling jacket 5 Shield container 5a Hole 6 Lid

Claims (3)

[Claims] 1. Surrounding an object to be heated so as to cover the object from above,
A heater container having a vertical cylindrical shape with an open lower portion and a closed upper portion and a heater attached to the inner surface, and a lower portion provided slightly below and slightly below the lower end of the heater container to heat an object to be heated from below. A heater, a vertical cylindrical shielded container surrounding the heater container so as to cover the heater container from above, and having a lower portion opened and an upper portion sealed, and a vertical cylindrical shape closed container that can open the bottom portion and accommodates these. In the heating device having, the heater container and the shield container are provided with holes concentrically at the center of the ceiling, and a liftable lid that covers those holes is provided, and the lid is When at the lowermost position, the hole in the heater container is closed, when the lid is at the intermediate position, the hole in the heater container is open, when the hole in the shield container is closed, and when the lid is at the uppermost position, Heater vessel holes and seals Heating apparatus characterized by the de container bore is adapted to open both. 2. The heating apparatus according to claim 1, wherein a gas at 1 to 50 atm is sealed in the closed vessel. 3. The heating device according to claim 1, wherein a cooling jacket is attached to an outer surface of the closed vessel.