JP2001135543A - Device for heat treatment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a device for heat treatment, with which the magnetic field of a uniform and desired strength can be generated by a comparatively miniaturized magnetic field generating means, further, quick temperature elevation or cooling is enabled as well and the performance of a magnetic substance material or the like can be sufficiently improved. SOLUTION: A heating means 30 located between a vacuum container 2 and a magnetic field generating means 20 has an electric heater 31 located while surrounding the outer peripheral surface of the vacuum container 2, and a fluid cooling part 33 located between the electric heater 31 and the magnetic field generating means 20.

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 for performing a heat treatment in a magnetic field, and more particularly to a heat treatment apparatus for performing a heat treatment on a magnetic material such as an MR film or a GMR film in a strong magnetic field.

[0002]

2. Description of the Related Art A magnetic film, for example, a thin film of a Fe--Ni alloy formed on a substrate by a sputtering method or the like, which is a magnetic material used for a magnetic head, is subjected to heat treatment in a strong magnetic field. The magnetic properties can be exhibited.

Therefore, conventionally, a heat treatment apparatus has been proposed in which an electric furnace, an induction heating furnace, or the like is installed in a magnetic field formed by an electromagnet and heat treatment is performed therein. FIG. 7 shows a schematic configuration of an example of a conventional heat treatment apparatus.

[0004] As shown in FIG. 7, the heat treatment apparatus 1 A has a vacuum vessel 2 having a cylindrical shape, and magnetic field generating means 20 disposed outside the vacuum vessel 2. The vacuum vessel 2 has a holder support device 4 attached to the upper portion thereof, and a holder 3 holding an object to be heat-treated such as a magnetic material is inserted into and held by the support device 4. The magnetic field generating means 20 includes a pair of electromagnets 21 facing each other outside the vacuum vessel 2.
And a coil 23.

The outer surface of the vacuum vessel 2 and the magnetic core 2 of the electromagnet 21
The heating means 100 is provided between the heating means 100 and the second end face.
Normally, the heating means 100 is configured by disposing an electric heater 101 at a predetermined distance from the outer surface of the vacuum vessel 2 and surrounding the outer peripheral surface of the vacuum vessel 2.
For example, as shown in FIG. 7, the electric heater 101 is provided on the inner peripheral surface of the heater support body 102 made of brick or ceramic and disposed around the vacuum container 2 and facing the outer peripheral surface of the vacuum container. For example, a spiral groove 103 is provided, and this groove 10
3 is provided with a heating wire such as a nichrome wire 104. A heat insulating material 105 such as alumina felt or brick is provided on the outer peripheral surface of the heater support 102.
Is arranged so that the temperature of the heating means 100 is not transmitted to the electromagnet 21.

[0006]

However, in the conventional heat treatment apparatus, since the heating means 100 having the above-described structure is provided between the outer peripheral surface of the vacuum vessel 2 and the magnetic core 22 of each electromagnet 21, it is inevitable. Core 2 of electromagnet 21 forming a pair
The distance between 2 and 22 had to be large. Normal,
The distance (L) between the inner surface of the vacuum vessel 2 and the magnetic core 22 is 1
35 to 250 mm, the outer diameter of the vacuum vessel 2 (D1)
Is set to, for example, 240 mm, the distance (L0) between the magnetic cores 22 of the electromagnet 21 is 520 to 700 mm
Met.

Therefore, in order to satisfy a uniform magnetic field and a predetermined magnetic field strength, the size of the electromagnet itself constituting the magnetic field generating means 20 must be increased, and the current flowing through the electromagnet 21 must be increased. Absent. Due to the increase in weight and current accompanying the increase in size of such electromagnets, it becomes necessary to increase installation space and power supply facilities.

Increasing the size of the electromagnet increases the size of the entire heat treatment apparatus and significantly increases the cost of the apparatus and the cost of operating the apparatus.

Further, in the above-mentioned heating means, since a brick or the like is used as a heat insulating material, dust is generated, and there is a problem when used in a clean room.

Therefore, an object of the present invention is to generate a uniform and desired strength magnetic field with a relatively small magnetic field generating means, and also to perform rapid temperature-rising cooling, and to reduce the temperature of magnetic material and the like. An object of the present invention is to provide a heat treatment apparatus capable of sufficiently improving performance.

Another object of the present invention is to improve the degree of freedom of design without the magnetic field generating means being heated by the temperature rise of the electric furnace, so that the material selection is not restricted,
Further, it is an object of the present invention to provide a heat treatment apparatus capable of reducing the size of the entire apparatus, reducing the cost of the apparatus, suppressing power consumption, and greatly reducing the operation cost of the apparatus.

Still another object of the present invention is to provide a heat treatment apparatus which does not use a part which may generate dust as an apparatus constituent part and which can be used in a clean room.

[0013]

The above object is achieved by a heat treatment apparatus according to the present invention. In summary, the present invention relates to a heat treatment apparatus having a vacuum vessel, a magnetic field generating means disposed outside the vacuum vessel, and a heating means disposed between the vacuum vessel and the magnetic field generating means. Wherein the heating means has an electric heater arranged so as to surround the outer peripheral surface of the vacuum vessel, and a fluid cooling unit arranged between the electric heater and the magnetic field generating means. Heat treatment equipment.

According to one embodiment of the present invention, the heating means is arranged between the vacuum vessel and the electric heater, and is provided with an electrically insulating material surrounding the outer peripheral surface of the vacuum vessel. It includes the inner tube. Preferably, the vacuum vessel and the inner tube are made of an optically transparent material.

According to another embodiment of the present invention, the electric heater has a shape in which a resistance heating wire is covered with an electric insulating tube. Preferably, the resistance heating wire is
It is a nichrome wire or a noble non-magnetic metal heating element, and the electric insulating tube is a tube woven of alumina fiber or a plurality of quartz or alumina tubular bodies connected to each other.

According to another embodiment of the present invention, in the electric heater, currents flowing in adjacent resistance heating lines are in opposite directions, and magnetic field generation due to an applied current is non-inductive.

According to another embodiment of the present invention, the fluid cooling unit is a water cooling jacket through which a fluid flows.

According to another embodiment of the present invention, a sheet-like electric insulating material can be arranged between the water cooling jacket and the electric heater. Preferably, the water cooling jacket is made of metal.

According to another embodiment of the present invention, the magnetic field generating means is constituted by an electromagnet arranged outside the vacuum vessel and opposed to the vacuum vessel, and a distance from an end face of a magnetic core of the electromagnet to an inner face of the vacuum vessel. (L) is 0.05 times or more and 0.15 times or less of the distance (L0) between the magnetic cores of the magnetic field generating means, specifically, 15 mm or more and 45 mm or less, preferably 15 mm or more and 30 mm or less. It is said.

[0020]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a heat treatment apparatus according to the present invention will be described in more detail with reference to the drawings.

FIG. 1 shows a schematic overall configuration of an embodiment of a heat treatment apparatus 1 according to the present invention. The heat treatment apparatus 1 of the present embodiment
Like the conventional heat treatment apparatus 1A, the heat treatment apparatus includes a vacuum vessel 2 and a magnetic field generating means 20 arranged outside the vacuum vessel 2.

In this embodiment, the vacuum container 2 is a stepped cylinder having a container main body 2A having a small diameter and a large-diameter container mounting portion 2B integrally formed on the upper part of the container main body 2A. Shaped container. The lower end of the container body 2A is closed,
The upper end of the container mounting portion 2B is open. The upper end of the container is sealed by attaching a holder support device 4 for supporting the holder 3 installed in the container to the upper end of the container. An annular shoulder 2C formed between the container body 2A of the vacuum container 2 and the container mounting portion 2B is placed on the base 5, and the vacuum container 2 is held in place.

The vacuum vessel 2 is preferably made of ceramics such as quartz glass because it is stable during rapid cooling. In the present invention, as will be described in detail later, since the heating in a vacuum by the heating means 30 is mainly performed by radiant heat, the quartz glass is preferably optically transparent. The thickness of the vacuum container 2 can be 2 to 6 mm, and is 3 mm in this embodiment.

The holder 3 has a diameter of 100 to 2 having an Fe—Ni alloy film formed by, for example, sputtering.
About 30 trays 6 for mounting substrates of about 00 mm are held by a support shaft 7, and the upper end of the support shaft 7 is suspended from a holder support device 4.

It is preferable that the holder support device 4 rotatably holds the holder 3 so that the object to be heat-treated held by the holder 6 can be changed in the direction of the magnetic field. Therefore, in this embodiment, the holder support device 4
A drive motor 8 is mounted on the holder 3 so that the rotation support shaft 7 of the holder 3 can be driven to rotate.

After the holder 4 is attached to the upper end of the vacuum vessel, the vacuum vessel 2 is evacuated by a vacuum pump (not shown) provided at the upper end of the vacuum vessel to thereby obtain a predetermined vacuum. State can be maintained.
For example, when the object to be heat-treated is a magnetic metal thin film or the like, it is preferable that the object be heat-treated in a vacuum, specifically, a vacuum state of 1 Pa or less to prevent oxidation of the metal thin film.

The holder supporting device 4 is detachably attached to the upper end of the container.
Can be lifted out of the container 2 together with the holder supporting device 4 by the elevator 10, and in this state, an object to be heat-treated such as a magnetic material is held by the holder 3.
Or can be taken out of the holder 3.

The magnetic field generating means 20 includes a pair of electromagnets 21 arranged facing each other. Each electromagnet 21 has a magnetic core 22 and a coil 23. According to the present invention, as will be described in detail later, the thickness of the heating means 30 disposed between the vacuum vessel 2 and the magnetic core 22 can be reduced, so that the magnetic cores 22 and 22 of the pair of electromagnets 21 can be reduced. The distance between them can be shortened, so that the electromagnet 21 itself can be downsized. Further, according to the present invention, since the magnetic core 22 is not heated, a material having low heat resistance can be used. For this reason, in the present embodiment, the magnetic field density generated by the magnetic field generating means 20 is 500 Gauss or more, particularly 10 gauss.
It can be about 00 Gauss to 20000 Gauss. The distance (L0) between the magnetic cores 22 in this embodiment (see FIG. 2) is 300
mm.

2 and 3, the outer surface of the container body 2A of the vacuum container 2 and the electromagnet 21
Between the end face of the magnetic core 22 and a thin heating means 30. According to the present invention, the heating means 30 includes an electric heater 31 by electric resistance heating. Such a heating means 30 is preferably inexpensive in cost as compared with an induction heating means whose power supply is expensive.

More specifically, the heating means 30 comprises an electrically insulated inner tube 32 surrounding the outer peripheral surface of the vacuum vessel main body 2A, and a predetermined distance from the inner tube 32. And a water cooling jacket that constitutes a fluid cooling unit 33 that is disposed. The inner tube 32 can be made of a quartz glass tube having a thickness of 2 to 6 mm. A gap (G1) of 2 to 4 mm is provided between the inner tube 32 and the outer peripheral surface of the vacuum vessel body 2A. In the present embodiment, since the outer diameter (D1) of the vacuum vessel main body 2A is 240 mm, the inner diameter (D2) of the inner tube 32 is 245 mm. The axial length (L1) of the inner tube 32 was 450 mm.

The water cooling jacket 33 includes an inner wall 34 and an outer wall 3.
5 and a cylindrical body having a double-pipe structure, the upper end and the lower end of which are closed by an upper wall 36 and a lower wall 37, respectively.
In this embodiment, as shown in FIG.
It is longer in the axial direction, but on the lower extension,
An annular support plate 38 is integrally fixed, and the inner cylindrical tube 32 is fixed.
I support. Although not shown, the water cooling jacket 33 has a water supply port formed at a lower portion and a water discharge port formed at an upper portion, and a cooling fluid, which is usually water, flows through the water cooling jacket 33. The cooling fluid R may be circulated.

The water cooling jacket 33 is not formed in a cylindrical shape continuous in the circumferential direction as shown in FIG.
It can also be formed to have a cut 39 extending along the axial direction. In this case, the terminal of the heater 31 installed inside the water cooling jacket 33 can be taken out by using the cut 39.

The water cooling jacket 33 is made of a material having good heat conductivity such as metal. In this embodiment, the inner wall 34, the outer wall 35, the upper wall 36, the lower wall 37 and the like are formed of a stainless steel plate having a thickness of 3 mm. Produced. Between the inner surface of the inner wall 34 of the water-cooling jacket 33 that surrounds the inner tube 32 and the inner tube 32, 8 to 1 is provided for disposing the heater 31.
A gap (G2) of 3 mm is provided. In this embodiment, since the outer diameter (D3) of the inner tube 32 is 253 mm, the inner diameter (D4) of the water cooling jacket 33 is 272 mm. or,
The axial length of the inner wall 34 of the water cooling jacket 33 was set to a size that completely covers the heating means 30.

Next, the heating means 30 will be further described.
According to the present invention, as described above, the heating means 30 has the electric heater 31 and is wound around the outer circumference of the inner cylindrical tube 32 in a spiral manner.

According to the present invention, the electric heater 31 has the configuration shown in FIG.
As shown in FIG. 7, the resistance heating and heating wire 31A is covered with an electrically insulating tube 31B. Resistance heating heating wire 31
As A, a nichrome wire or a noble metal non-magnetic metal heating element such as platinum can be suitably used. Electrical insulation tube 31
B is a tube formed by knitting fibrous alumina fibers, or a plurality of tubular bodies formed of quartz or alumina. In this embodiment, the resistance heating / heating wire 31A has a diameter of 2.0 to 2.0 mm.
An outer diameter of 3.5 mm was used, in which a 6 mm nichrome wire was covered with a tube 31B knitted with alumina fiber.

Since the resistance heating wire 31A is placed in the magnetic field by the magnetic field generating means 20 as described above, it receives a force due to the interaction with the magnetic field due to the current for heating, and Will come into contact with each other. Therefore, it is preferable that the resistance heating wire 31A be electrically insulated by the insulating tube 31B.

Further, in order to reduce the force due to the interaction, the direction in which the current flows through the resistance heating wire 31A is arranged so that the magnetic field generated thereby is canceled.
A so-called non-induction winding is preferable.

That is, as shown in FIG. 6, the heater 31 is wound in a single-layer winding around the inner tube 32 in a double-wire state connected at one end, that is, in a U-shape. Therefore, the directions of the currents flowing in the upper and lower resistance heating lines 31A adjacent to each other in the axial direction are reversed, whereby the magnetic fields generated by flowing through the resistance heating lines 31A cancel each other out. If only one heater 31 is wound, as described above, when a current flows through the resistance heating / heating wire 31A, the resistance heating / heating wire 31A receives a force due to the magnetic field from the magnetic field generating means 20, The heater 31 moves or vibrates.

Further, the heating current is preferably a direct current because such a cancellation of the force can be stabilized. The heating means 30 is usually provided with a control means for controlling the temperature, and controls the energization of the heater 31.

The temperature range for ordinary heat treatment is 150 ° C. to 5 ° C.
Although it is about 00 ° C., when a film having a high ordering temperature of the structure of the magnetic film is subjected to heat treatment, the temperature is particularly set to about 500 ° C. to 800 ° C. In the case of heat treatment of a magnetic film for an MR element, the cooling rate is 50 ° C./min or more,
It is set at 00 ° C / min to 200 ° C / min.

It is preferable that no heat insulating material is provided around the heater 31. However, in this embodiment, since the water cooling jacket 33 is made of stainless steel, the sheet-like electric material is provided between the water cooling jacket 33 and the heater 31. It is preferable to arrange an alumina sheet 40 as an insulating material. The alumina sheet 40 may have a thickness of about 1 to 3 mm.
It is preferable that the thickness of the electric insulating material between the heater 31 and the water cooling jacket 33 be 4 mm or less. The heater 31 may be wound around the inner peripheral surface of the alumina sheet 40 without providing the inner tube 2.

As understood from the above embodiment, according to the present invention, the gap (G) between the outer surface of the vacuum
3) is 27.5 mm, which is much shorter than that of the conventional device shown in FIG.

According to the experimental study of the present inventors, the magnetic core 22 of the magnetic field generating means 21 facing the water-cooling jacket 33.
Is from 0.05 to 0.15 times the distance (L0) between the magnetic cores of the magnetic field generating means 21, specifically from 15 mm to 45 mm.
It has been found that the thickness is preferably not more than 30 mm, particularly preferably not more than 30 mm.

The heat treatment apparatus further includes a power supply for the magnetic field generating means, a magnetic field measurement control device, a vacuum pump control unit for evacuating the vacuum vessel, a mechanism for controlling the operation sequence of the entire device, and the like. Each of these elements,
Since a well-known one can be used, a detailed description thereof will be omitted.

[0045]

As described above, according to the present invention,
In a heat treatment apparatus having a vacuum vessel, a magnetic field generating means arranged outside the vacuum vessel, and a heating means arranged between the vacuum vessel and the magnetic field generating means, the heating means removes an outer peripheral surface of the vacuum vessel. Since it is configured to have the electric heater disposed so as to surround and the fluid cooling unit disposed between the electric heater and the magnetic field generating means, (1) a relatively small magnetic field generating means As a result, it is possible to generate a magnetic field having a uniform and desired strength, and it is also possible to rapidly raise and lower the temperature and sufficiently improve the performance of the magnetic material and the like. (2) The magnetic field generating means is not heated by increasing the temperature of the electric furnace, so that the material selection is not restricted,
Improving the degree of freedom of design, miniaturizing the configuration of the entire device, reducing the cost of the device, and suppressing the power consumption,
The equipment operation cost can be significantly reduced. (3) As a component of the device, a component that may generate dust is not used, and can be used in a clean room. Such an effect can be obtained.

[Brief description of the drawings]

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

FIG. 2 is a partial cross-sectional view showing a positional relationship among a vacuum vessel, a heating unit, and an electromagnet.

FIG. 3 is a partially enlarged sectional view of a heating unit.

FIG. 4 is a perspective view showing an overall view of one embodiment of a water cooling jacket.

FIG. 5 is a sectional view of an electric heater.

FIG. 6 is a perspective view illustrating a method of installing an electric heater.

FIG. 7 is a schematic configuration sectional view of a conventional heat treatment apparatus.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Heat treatment apparatus 2 Vacuum container 3 Holder 4 Holder support device 20 Magnetic field generating means 21 Electromagnet 22 Magnetic core 23 Coil 30 Heating means 31 Electric heater 32 Inner tube 33 Fluid cooling part (water cooling jacket) 40 Insulating sheet

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Hiroki Kobayashi 2-7-33 Fukuura, Kanazawa-ku, Yokohama, Kanagawa Prefecture Inside Futec Furnace Co., Ltd. (72) Inventor Kazuo Miwa 2-7 Fukuura, Kanazawa-ku, Yokohama-shi, Kanagawa −33 Inside Futec Furnace Co., Ltd.

Claims (11)

[Claims] 1. A heat treatment apparatus comprising: a vacuum vessel; magnetic field generating means disposed outside the vacuum vessel; and heating means disposed between the vacuum vessel and the magnetic field generating means. The heat treatment apparatus includes: an electric heater disposed to surround an outer peripheral surface of the vacuum vessel; and a fluid cooling unit disposed between the electric heater and the magnetic field generating unit. . 2. The method according to claim 1, wherein the heating means includes an electrically insulating inner tube disposed between the vacuum vessel and the electric heater and surrounding the outer peripheral surface of the vacuum vessel. The heat treatment apparatus according to claim 1, wherein: 3. The heat treatment apparatus according to claim 1, wherein the electric heater has a shape in which a resistance heating wire is covered with an electric insulating tube. 4. The resistance heating wire is a nichrome wire or a noble metal non-magnetic metal heating element, and the electrical insulation tube is a tube woven from alumina fiber, or a quartz or alumina tube. 4. The heat treatment apparatus according to claim 3, wherein a plurality of bodies are connected. 5. The heat treatment apparatus according to claim 3, wherein the electric heaters have currents flowing in adjacent resistance heating lines opposite to each other. 6. The heat treatment apparatus according to claim 1, wherein the fluid cooling unit is a water cooling jacket through which a fluid flows. 7. The heat treatment apparatus according to claim 6, wherein a sheet-like electric insulating material is disposed between the water cooling jacket and the electric heater. 8. The heat treatment apparatus according to claim 6, wherein the water cooling jacket is made of metal. 9. The magnetic field generating means is constituted by an electromagnet disposed opposite to the outside of the vacuum vessel, and a distance (L) from an end face of a magnetic core of the electromagnet to an inner face of the vacuum vessel.
Is 0.05 of the distance (L0) between the magnetic cores of the magnetic field generating means.
The heat treatment apparatus according to any one of claims 1 to 8, wherein the heat treatment time is not less than twice and not more than 0.15 times. 10. A distance (L) from an end face of the magnetic field generating means to an inner face of the vacuum vessel is 15 mm or more and 45 m or more.
The heat treatment apparatus according to any one of claims 1 to 8, wherein m is not more than m. 11. A distance (L) from an end face of the magnetic field generating means to an inner face of the vacuum vessel is 15 mm or more and 30 m or more.
The heat treatment apparatus according to any one of claims 1 to 8, wherein m is not more than m.