JP2003100426A - Hot blast generator by induction heating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hot blast generator which can remove heat generated in an induction coil by a compact constitution. SOLUTION: This device is constituted so that cooling water pipes 13 made of resin are wound between electric wires 1a of neighbored induction coils to be wound around the outer peripheral face of a cylindrical heater case 6, and that generated heat by the electric wires 1a and heat-transferred heat via the heater case 6 are made to be cooled by the cooling water to circulate in the cooling water pipes 13.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hot air generator by induction heating, and is particularly useful when applied to cooling the induction coil.

[0002]

2. Description of the Related Art In induction heating, as shown in FIG. 4, an alternating magnetic flux Φ generated by passing an alternating current I through an induction coil (inductor) 1 is a conductor arranged inside the induction coil 1. An induction current (eddy current) I _e is passed through the heating work 2 and the Joule heat generated thereby causes the heating work 2 to move.
Is to heat. Induction heating has the characteristics of good responsiveness during temperature control and extremely excellent heating efficiency. Typical applications of induction heating technology include melting furnaces, welding, and thermal processing equipment for metal materials such as brazing.

On the other hand, in the case of heating a gas, a liquid or the like by this induction heating, a method of secondarily heating an object to be heated by using the heating work 2 shown in FIG. 4 as a heat exchanger is general. FIG. 5: is explanatory drawing which shows notionally the fluid heating apparatus in the case of heating gas using induction heating. As shown in the figure, the fluid heating device is an indirect heating by heat transfer from a heating work, unlike a direct heating such as a metal material as a heating object, and therefore, heating is performed efficiently in order to perform heating. It is necessary to maximize the contact area between the work and gas. Therefore, the diameter is 1 mm to 2 mm and the wall thickness is 0.05 mm to 0.1 m.
An assembly obtained by bundling a large number of metal microtubes 3 of m is housed in a cylindrical case 5 made of ceramics, and an induction heating unit is provided around which an induction coil 1 is wound. Here, a high frequency alternating current (20 to 50 kH) is applied to the induction coil 1.
When z) is supplied, the fine tube 3 is instantly heated, and at the same time, the gas passing through the fine tube 3 is heated by heat transfer from the inner wall of the tube. At this time, the material of the micro tube 3 is preferably a magnetic material, but a non-magnetic material can be heated at a frequency of 400 kHz or higher.

FIG. 6 shows a PEB which is one of semiconductor manufacturing equipment.
(Post Exposure Bake) A hot air generator (induction heater) A that uses induction heating and is used as an auxiliary heating device.
FIG. As shown in the figure, this hot air generator A has a diameter of 1 mm, a length of 70 mm, and a wall thickness of 0.05 m.
The micro tube 3 of m is housed in a wide rectangular tubular case 6, and a heat resistant coated electric wire of ² mm ^{2 is provided on} the outer circumference of the induction coil 1.
It is configured to be wound as.

FIG. 7 is a longitudinal sectional view showing a state during heating (baking) when the hot air generator A is mounted on the PEB device. The baking process by the PEB device is to place the semiconductor wafer 8 on the main hot plate 7 and control the temperature variation within the surface of the semiconductor wafer 8 with high accuracy of 0.2 ° C. or less. At this time, hot air having a temperature substantially equal to the baking temperature (about 140 ° C.) flows from the hot air generator A on the upper surface of the semiconductor wafer 8. Here, the main role of the hot air generator A is to supply hot air controlled in an arbitrary temperature distribution in the width direction to the surface of the semiconductor wafer 8 when the semiconductor wafer 8 is baked. 8 is to make the in-plane temperature variation uniform in a high dimension. In FIG. 7, 9 is a chamber cover and 10
Is a hot air outlet.

The actual baking process in the PEB apparatus is a series of steps (wafer loading → baking → cooling → wafer unloading) that are repeatedly performed continuously, but the user may change the baking temperature condition between the steps. . In this case, when the bake temperature of the semiconductor wafer 8 is changed, the hot air generator A must immediately meet the changed temperature condition within a time when the temperature of the main hot plate 7 reaches the stable region. That is, it is necessary to provide a hot air generator A having excellent thermal responsiveness, with a structure that minimizes the thermal inertia of the microtubes 3 (see FIG. 6) that generate heat.

Further, when the hot air generator A is mounted on the PEB device, the parts inside the device are in a state of being close to the main body of the hot air generator A because the installation space is very limited. As described above, since the PEB device performs high-dimensional temperature control, it is very susceptible to changes in the environmental temperature inside and outside the device. Therefore, it is important that the hot air generator A does not radiate heat to the outside as much as possible except for heat radiated by hot air during mounting.

[0008]

FIG. 8 is a vertical cross-sectional view for explaining the installation position of the hot air generator and the temperature of the peripheral parts in the PEB device according to the prior art. As shown in the figure, in the hot air generator A in the PEB device, the heat generation temperature of the fine tube 3 is 400 ° C, and the surface temperature of the induction coil at this time is 200 ° C. Such a rise in the temperature of the induction coil is also a factor in heat transfer from the fine tube 3, but in addition to this, it is considered that Joule loss due to a high-frequency alternating current flowing in the induction coil and heat generation due to self-induction. In this way, the heat generated in the induction coil does not contribute to the generation of hot air at all, and is simply wasted to the outer peripheral portion of the hot air generator A. Therefore, heat is transferred to the components of the PEB device arranged around the hot air generator A, which causes a problem that the temperature control system is adversely affected. Further, a cooling plate 11 for forcibly cooling the baked wafer is provided below the hot air generator A,
When the hot air generator A is in operation, the radiant heat of the hot air generator A causes a problem that the temperature rises to around 100 ° C.

As a method of suppressing heat release from the hot air generator A to the outside, a method of reducing Joule loss due to current by increasing the cross-sectional area of the induction coil, and adding a cooling mechanism to the electric wire of the induction coil. There is a method to forcibly remove the heat generated by. However, in the former case, the wire becomes thicker, so that the outer dimension of the main body of the hot air generator A becomes large, which causes a problem when it is mounted on the PEB device. On the other hand, in the latter case, a method is generally used in which the induction coil itself has a pipe structure and the coil is forcibly cooled by flowing cooling water through this pipe. Since the diameter of the coil becomes large as in the former case, there is a problem in terms of external dimensions when mounting on the PEB device.

In view of the above-mentioned prior art, the present invention efficiently removes heat generated in the induction coil with a compact structure, suppresses heat release from the heating element, and further reduces the current supplied to the induction coil. Therefore, it is an object of the present invention to provide a hot air generator by induction heating that can suppress the heat generation and thereby improve the overall thermal efficiency.

[0011]

The structure of the present invention for achieving the above object is characterized by the following points.

1) An induction coil is wound around the outer peripheral surface of a cylindrical heater case, and a microtube assembly having a large number of microtubes, which are conductors, is inserted into the inner space of the induction coil. In a hot-air generator by induction heating configured to heat a fluid to be heated which is heated by induction heating and which flows in each fine tube heated by the induction heating, it is wound around the heater case so as to form an induction coil. A cooling water pipe made of resin should be wound in parallel between adjacent electric wires so that they are in close contact with each other.

2) An induction coil is wound around the outer peripheral surface of a cylindrical heater case, and a microtube assembly having a large number of microtubes, which are conductors, is inserted into the inner space of the induction coil. In an induction heating hot air generator configured to heat by induction heating and to heat a fluid to be heated which flows through each fine tube heated by the induction heating, the heater case has a two-layer structure of different materials in the thickness direction. In addition, it is configured to have both a function as a heat insulating material for insulating the heat generated by each fine tube as a heating element and a function as a structure of the heater case.

3) An induction coil is wound around the outer peripheral surface of a tubular heater case, and a microtube assembly having a large number of microtubes, which are conductors, is inserted into the inner space of the induction coil. In an induction heating hot air generator configured to heat by induction heating and heat a fluid to be heated which flows through each fine tube heated by the induction heating, the induction coil winds two electric wires around a heater case at the same time. Two parallel coils made by turning.

4) The induction coil is wound around the outer peripheral surface of the tubular heater case, and a microtube assembly having a large number of microtubes, which are conductors, is inserted into the inner space of the induction coil. In a hot air generator by induction heating configured to heat a fluid to be heated which is heated by induction heating and which flows in each of the fine tubes heated by the induction heating, it is wound adjacent to the heater case so as to form an induction coil. A resin-made cooling water pipe is wound around the turned electric wires so as to be in close contact with the electric wires, and the heater case has a two-layer structure made of different materials in the thickness direction to generate each fine tube which is a heating element. It is configured to have both the function as a heat insulating material for heat insulation and the function as a heater case structure,
Further, the induction coil is two parallel coils formed by winding two electric wires around the heater case at the same time.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. In each embodiment,
The same parts will be denoted by the same reference numerals, and overlapping description will be omitted.

FIG. 1 is a view conceptually showing a vertical cross-sectional shape of a hot-air generator by induction heating according to a first embodiment of the present invention. (A) shows the entire structure, and (b) shows. FIG. 4 is an explanatory diagram showing a heat transfer state thereof. As shown in both figures,
The induction coil 1 is wound around the outer peripheral surface of the cylindrical heater case 6, and the fine tube 3 which is a conductor is provided in the inner space thereof.
A microtubule assembly in which a large number of are assembled is inserted. As a result, each microtube 3 is heated by induction heating, and the fluid to be heated flowing through each microtube 3 heated by this induction heating is heated.

Further, in the hot air generator according to this embodiment,
A resin-made cooling water pipe 13 is wound around the electric wires 1a forming the induction coil 1 so as to be closely attached to the electric wires 1a. More specifically, a resin cooling water pipe 13 is laid in parallel between the windings of the electric wire 1a,
In order to enhance the thermal conductivity of the coating 1b of the electric wire 1a and the cooling water pipe 13, the gap is filled with the same kind of resin 14. As the electric wire 1a used here, for example, a fluororesin-coated electric wire (heat resistant temperature of 260 ° C.) is suitable.

The movement of heat in the hot air generator according to this embodiment, as shown in FIG. 1B, goes to the cooling water pipe 13 via the heater case 6 and the resin 14, and flows in the cooling water pipe 13. It is cooled by the cooling water. As a result, the heat generated in the electric wire 1a can be efficiently removed. In addition, the heat transferred from the fine tubes 3 which are heat generating elements through the heater case 6 can be similarly removed by the cooling water flowing through the cooling water pipe 13.

FIG. 2 is an explanatory view conceptually showing a vertical cross-sectional shape of a part of the hot air generator by induction heating according to the second embodiment of the present invention. As shown in the figure, the heater case 16 of the hot air generator according to the present embodiment includes a ceramic heat resistant layer 16a and a ceramic fiber heat insulating layer 16
It has a two-layer structure of b. The heat-resistant layer 16a mainly serves as a structure of the heater case 16, and the heat-insulating layer 16b has a heat-insulating effect of suppressing heat conduction from a fine tube which is a heating element.

The performance required for the heater case 16 is that it serves as a structure for accommodating the microtubes 3 (see FIG. 1) and maintaining the shape of the heater, and the heater case 16
Although it has a role of suppressing heat transfer from the fine tubes 3 that generate heat inside, according to this embodiment, the heat-resistant layer 16 can share the former function and the heat insulating layer 16b can share the latter function. Two different types of functions required for the heater case 16 can be excellently achieved at the same time.

FIG. 3 is a view conceptually showing a longitudinal cross-sectional shape of a hot air generator by induction heating according to a third embodiment of the present invention in comparison with the prior art. FIG.
(B) shows this embodiment, respectively. As shown in both figures, in the hot air generator according to this embodiment, the induction coil 21 has two
The two electric wires 21a and 21b are simultaneously wound around the heater case 6 to form two parallel coils.

According to this embodiment, the two electric wires 21a, 21
It is possible to wind b at the same time and reduce the current flowing per wire by half. Naturally, the heat generated by Joule heat can be reduced to half.

Of course, it is also possible to use a hot air generating device that incorporates all the features of the above three embodiments. In this case, it is possible to provide a hot air generator having a compact structure and good thermal efficiency.

[0025]

As described above in detail with reference to the embodiments, according to the invention described in [Claim 1], the heat generated in the electric wire is generated by running the cooling water pipe in parallel with the coil electric wire. Can be removed efficiently. In addition, the heat transferred from the fine tubes, which are the heating elements, through the heater case can be similarly removed by the cooling water pipe.

According to the invention described in [Claim 2], two kinds of materials satisfying two kinds of different performances are used.
With the layered structure, while maintaining the shape of the hot air generator, it is possible to suppress the heat released to the outside through the heater case and to reduce the electric power required for induction heating.

According to the invention described in [Claim 3], by arranging one to two coil electric wires in parallel, it is possible to expect an effect of halving the current flowing through one electric wire and suppressing the heat generation amount of the electric wire. Further, since the density between the coil electric wires is increased, the magnetic flux can efficiently pass through the fine tube, and the effect of improving the heat generation efficiency can be expected.

According to the invention described in [Claim 4],
It is possible to obtain a hot air generator having a compact structure and excellent thermal efficiency, which can obtain the effects of superimposing the effects of the invention described in [Claim 1] to [Claim 3].

[Brief description of drawings]

FIG. 1 is a view conceptually showing a vertical cross-sectional shape of a hot-air generator by induction heating according to a first embodiment of the present invention,
(A) is an explanatory view showing the whole structure, and (b) is an explanatory view showing the heat transfer state.

FIG. 2 is an explanatory view conceptually showing a vertical cross-sectional shape of a part of a hot air generator by induction heating according to a second embodiment of the present invention.

FIG. 3 is a view conceptually showing a vertical cross-sectional shape of a hot air generator by induction heating according to a third embodiment of the present invention in comparison with a conventional technique, (a) being a conventional technique, and (b) being a diagram. This form is shown respectively.

FIG. 4 is an explanatory diagram for explaining the principle of induction heating.

FIG. 5 is an explanatory view conceptually showing a fluid heating device using induction heating.

FIG. 6 shows PEB (Post Exp) which is one of the semiconductor manufacturing equipment.
It is explanatory drawing which shows the hot air generator (induction heater) which applied the induction heating used as an auxiliary heating device of an osure bake) apparatus.

7 is a vertical cross-sectional view showing a state during a heating (baking) process when the hot air generator A is mounted on the PEB device shown in FIG.

FIG. 8 is a vertical cross-sectional view for explaining an installation position of the hot air generator and temperatures of peripheral components.

[Explanation of symbols]

1 induction coil 1a electric wire 3 Micro tube 6 heater case 13 Cooling water pipe 16 heater case 16a heat-resistant layer 16b heat insulation layer 21 induction coil 21a, 21b electric wire

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Claims (4)

[Claims] 1. An induction coil is wound around an outer peripheral surface of a cylindrical heater case, and a microtube assembly having a large number of microtubes, which are conductors, is inserted into the inner space of the induction coil. In a hot air generator by induction heating configured to heat the fluid to be heated which is heated by induction heating and which flows in each fine tube heated by the induction heating, it is wound around the heater case so as to form an induction coil. A hot air generator by induction heating, characterized in that a resin cooling water pipe is wound in parallel between adjacent electric wires so as to be in close contact with the electric wires. 2. An induction coil is wound around an outer peripheral surface of a tubular heater case, and a microtube assembly having a large number of microtubes, which are conductors, is inserted into the inner space of the induction coil. A hot air generator by induction heating configured to heat a fluid to be heated which is heated by induction heating and flows into each fine tube heated by the induction heating, wherein the heater case has a two-layer structure of different materials in a thickness direction. A hot-air generation device by induction heating, which is configured to have both a function as a heat insulating material for insulating heat generated by each fine tube as a heating element and a function as a structure of a heater case. 3. An induction coil is wound around an outer peripheral surface of a tubular heater case, and a microtube assembly having a large number of microtubes, which are conductors, is inserted into the inner space of the induction coil. In the hot air generator by induction heating, which is configured to heat by induction heating and to heat the fluid to be heated which flows through each fine tube heated by this induction heating, the induction coil winds two electric wires around a heater case at the same time. A hot-air generator by induction heating, which is composed of two parallel coils that are rotated. 4. An induction coil is wound around an outer peripheral surface of a tubular heater case, and a microtube assembly having a large number of microtubes, which are conductors, is inserted into the inner space of the induction coil. In an induction heating hot air generator configured to heat by induction heating and to heat a fluid to be heated which flows through each fine tube heated by the induction heating, the heater is wound adjacent to the heater case so as to form an induction coil. A resin cooling water pipe is wound around the turned electric wires so as to be in close contact with the electric wires, and the heater case has a two-layer structure made of different materials in the thickness direction to generate each fine tube as a heating element. It is configured to have both a function as a heat insulating material for insulating heat and a function as a heater case structure. Further, the induction coil is formed by winding two electric wires around the heater case at the same time. A hot-air generator by induction heating, characterized by having two parallel coils.