JP2016143510A - Induction heating apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an induction heating apparatus which can improve, even when a flat plate-like induction heating target member is adopt and induction heating coils are solely used as heating means, the calorific power at a center portion of the induction heating target member.SOLUTION: An induction heating apparatus comprises: induction heating coils 12b and 12c arranged annularly so as to face an induction heating target member 40; an induction heating coil 12a which is arranged to face the induction heating target member 40, and which has, on the inner peripheral side of the induction heating coils 12b and 12c, an asymmetrical shape around the central axis of an annulus ring along the shape of the induction heating coils 12b and 12c; and inverters 14a to 14c which can individually supply power to the induction heating coils 12a to 12c. The induction heating coil 12b and 12c are each made up a plurality of induction heating coils arranged concentrically with one another.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an induction heating apparatus, and more particularly to an induction heating apparatus having a coil shape suitable for heat treatment of a semiconductor substrate.

  As a single wafer type induction heating apparatus for heat-treating a semiconductor substrate, those disclosed in Patent Documents 1 and 2 are known. In any of the induction heating devices disclosed in any document, a plurality of induction heating coils having an annular shape are arranged concentrically or spirally. And the some induction heating coil is comprised so that all may become a substantially symmetrical form around a central axis.

  The induction heating devices disclosed in the above patent documents are each configured to be able to individually control the power supplied to each of the plurality of induction heating coils. However, in the heating of the induction heating member by the induction heating coils arranged concentrically, there is a problem that the magnetic flux injected into the central portion is only the magnetic flux directed in the vertical direction, and the heat generation amount is lower than the surroundings.

  With respect to such a problem, in the induction heating device disclosed in Patent Document 1, the thickness of the induction heating member and the distance between the induction heating coil and the induction heating member are changed, and the center portion of the induction heating member is changed. The amount of heat generated is increased.

  In addition, in the induction heating device disclosed in Patent Document 2, in addition to the annular induction heating coil, a laser heating means for heating the center of the induction heating member is provided, so that the entire induction heating member is evenly distributed. It has been proposed to heat.

Japanese Patent No. 4336283 Japanese Patent No. 5127532

  It can be said that any of the induction heating devices having the above features is suitable for making the heat distribution of the induction heating member uniform.

  However, in the induction heating devices disclosed in Patent Documents 1 and 2, in order to increase the calorific value of the central portion of the induction heating member, in order to increase the form and thickness of the induction heating member, Since a configuration in which a heating means other than the induction heating coil is provided is employed, there remains a problem that the manufacturing cost increases and the control becomes complicated.

  Therefore, in the present invention, even if the above-mentioned problem is solved, a flat plate-shaped induction heating member is employed, and the heating means is only an induction heating coil, the amount of heat generated at the center of the induction heating member can be improved. An object of the present invention is to provide an induction heating device that can be realized.

  In order to achieve the above object, an induction heating apparatus according to the present invention includes a circular induction heating coil arranged in an annular shape so as to face an induction heating member, an opposite arrangement to the induction heating member, and An asymmetric induction heating coil having an asymmetric shape around the center axis of the circular ring along the shape of the circular induction heating coil and an electric power are individually supplied to each induction heating coil on the inner peripheral side of the circular induction heating coil. An induction heating device comprising: an inverter that makes it possible.

  In the induction heating apparatus having the above-described features, the circular induction heating coil may be configured by a plurality of induction heating coils arranged concentrically. With such a feature, the resolution at the time of supplying electric power increases, and more accurate temperature distribution control becomes possible.

  Moreover, in the induction heating apparatus having the above-described characteristics, it is preferable to include a rotating unit that rotates the member to be heated around the central axis of the circular induction heating coil. By having such characteristics, it is possible to suppress uneven temperature distribution occurring in the induction heating member and perform uniform heating with higher accuracy.

  According to the induction heating apparatus having the characteristics as described above, even if a flat induction heating member is employed and the heating means is only an induction heating coil, the amount of heat generated at the center of the induction heating member. The temperature distribution in the induction heating member can be equalized.

It is a figure which shows the circuit structural example of the induction heating apparatus which concerns on embodiment. It is a top view which shows the example of the specific form of the induction heating coil employ | adopted in the induction heating apparatus which concerns on embodiment. It is a figure which shows the arrangement | positioning form of the to-be-induced heating member and the induction heating coil in the induction heating apparatus which concerns on embodiment, and the generation | occurrence | production state of magnetic flux, and is a figure which shows the BB cross section of FIG. It is a top view which shows the form of the induction heating coil in the conventional induction heating apparatus which makes the form of all the some induction heating coils substantially symmetrical around a central axis. It is a figure which shows the structural example at the time of providing a rotation means in an induction heating apparatus. It is a graph which shows the temperature distribution at the time of trying the uniform heating of a to-be-induced heating member using the induction heating coil of the form shown in FIG. It is a graph which shows the temperature distribution at the time of trying the uniform heating of a to-be-induced heating member using the induction heating coil which concerns on this embodiment. It is a top view which shows the example at the time of setting the form of the asymmetric induction heating coil arrange | positioned inside the circular induction heating coil to the L type. It is a top view which shows the example at the time of setting the form of the asymmetric induction heating coil arrange | positioned inside a circular induction heating coil to N type.

  Hereinafter, embodiments of the induction heating apparatus of the present invention will be described in detail with reference to the drawings.

  First, the outline | summary of the whole induction heating apparatus which concerns on this embodiment is demonstrated with reference to FIG. An induction heating apparatus 10 shown in FIG. 1 includes induction heating coils 12a, 12b, and 12c, inverters (inverse conversion circuits) 14a, 14b, and 14c, chopper circuits 22a, 22b, and 22c, a converter (forward conversion circuit) 26, and a power source. The unit 30 is basically configured.

  In the induction heating apparatus 10 shown in FIG. 1, a circuit composed of chopper circuits 22a, 22b, and 22c, inverters 14a, 14b, and 14c, and induction heating coils 12a, 12b, and 12c is parallel to a converter 26 that will be described in detail later. It is configured by being connected to. Therefore, the induction heating device 10 according to the present embodiment includes a plurality of induction heating circuits capable of individually controlling power.

  The induction heating coils 12a, 12b, and 12c are coils to which inverters 14a, 14b, and 14c that can supply a high-frequency current are connected. In the case of this embodiment, a plurality of (three in the example shown in FIG. 1) induction heating coils 12a and 12b with respect to a single induction heating member 40 (for example, disk-shaped graphite: see FIGS. 2 and 3). , 12c are arranged close to each other. In the case of such an arrangement, when electric power is supplied to the coils, a mutual induction voltage Vm is generated between the induction heating coils 12a, 12b, and 12c arranged adjacent to each other.

  Inverters 14a, 14b, 14c employed in induction heating apparatus 10 shown in FIG. 1 are voltage type inverters. Resonant capacitors 32a, 32b are connected in series between the induction heating coils 12a, 12b, 12c and the inverters 14a, 14b, 14c, and a series resonant circuit is formed between them. Therefore, it can be said that the induction heating apparatus 10 shown in FIG. 1 constitutes a plurality (three) of self-resonant circuits.

  Inverters 14a, 14b, and 14c constitute a single-phase full-bridge inverter. As the switching element, an IGBT 16 is employed, and the diode 18 is connected in antiparallel in order to commutate the load current. A smoothing capacitor 20 and a smoothing coil (DCL: DC reactor) 21 for smoothing the DC voltage are provided in the previous stage of the bridge circuit.

  The chopper circuits 22a, 22b and 22c change the duty ratio by chopping the constant DC voltage output from the converter 26 with the IGBT 24 which is a switching element, and the average voltage input to the inverters 14a, 14b and 14c. Play a changing role. A smoothing capacitor 25 is provided between the chopper circuits 22a, 22b, and 22c and the converter 26.

  The converter 26 is constituted by a three-phase diode bridge configured using a diode 28. The three-phase alternating current supplied from the power supply unit 30 is converted into a direct current and supplied to the chopper circuits 22a, 22b, and 22c.

  In the induction heating apparatus 10 having such a configuration, the control means (not shown) controls the frequencies of the currents supplied to the induction heating coils 12a, 12b, and 12c to coincide with each other and synchronizes the current waveforms. Further, it is possible to avoid the influence of mutual induction (induction electromotive force) generated between the induction heating coils 12a, 12b, and 12c arranged in proximity, and to perform power adjustment for each of the inverters 14a, 14b, and 14c. . Even if the number of self-resonant circuits including the induction heating coils 12a, 2b, and 12c constituting the induction heating device 10 is arbitrarily increased or decreased, the effect of the present invention is not affected. By increasing the number of self-resonant circuits, the resolution at the time of performing temperature distribution control increases, and it becomes possible to perform more accurate temperature distribution control.

  Next, specific examples of the specific forms of the induction heating coils 12a, 12b, and 12c according to the embodiment will be introduced with reference to FIGS. First, the basic form of the induction heating coil in the induction heating apparatus 10 according to the present embodiment is an annular arrangement form. In the induction heating coil shown in FIG. 2, the induction heating coils 12b and 12c other than the induction heating coil 12a arranged at the center of the ring are shown to have the same form.

  That is, each of the induction heating coils 12b and 12c has a circular ring portion that is symmetric about the central axis when viewed in plan (for example, substantially symmetrical with respect to the center line A). Is formed. In addition, the annular portions formed by the induction heating coils 12b and 12c are formed concentrically. The graphite or the like that is the induction heating member 40 is formed in a disk shape like the outer peripheral shape of the induction heating coils 12b and 12c. For this reason, it becomes easy to heat the to-be-induced heating member 40 uniformly by forming and arranging the induction heating coils 12b and 12c concentrically. In addition, the arrangement | positioning form which looked at the induction heating coils 12b and 12c from the side surface is set to the form along the plate | board surface of the to-be-induced heating member 40 formed in flat form, as shown in FIG.

  The induction heating coil 12a disposed inside the induction heating coils 12b and 12c formed in an annular shape has an asymmetric form (for example, a center line A) around the central axis of the ring formed by the induction heating coils 12b and 12c. The base point is not line symmetric). Normally, as shown in FIG. 4, when the induction heating coil 12a1 disposed at the center is formed in an annular shape (symmetrical form), most of the magnetic flux acting on the center of the induction heating member 40 is a vertical magnetic flux. Yes, less eddy currents are generated around the direction of magnetic flux travel. For this reason, even when trying to heat the induction heating member 40 evenly, as shown in FIG. 6, the amount of heat generated near the center tends to be extremely low. Measures such as devising forms have been required.

  On the other hand, in the induction heating apparatus according to the present embodiment, as shown in FIGS. 2 and 3, the induction heating member has an asymmetric form around the central axis (the form shown in FIG. 2 is an I type). The magnetic flux traveling in the horizontal direction can also be applied near the center of 40 (see FIG. 3). For this reason, the generation amount of eddy current generated around the magnetic flux increases near the center of the induction heating member 40, and the amount of heat generation near the center of the induction heating member can be improved as shown in FIG. Therefore, the temperature distribution of the induction heating blank 40 can be equalized with high accuracy only by controlling the electric power supplied to the induction heating coils 12a, 12b, and 12c without elaborating the form of the induction heating member. It becomes possible.

  In addition, in the induction heating device 10 having the above-described characteristics, it is preferable to provide the rotation means 50 for the induction heating member 40. By horizontally rotating the induction heating member 40 itself heated by the induction heating coils 12a, 12b, and 12c around the central axis, it is difficult for the heat generation amount to be biased. Therefore, the temperature distribution when heating the induction heating member 40 can be made more uniform. The specific configuration of the rotating means 50 may be as shown in FIG. That is, a claw 52 for supporting the induction heating member 40, a rotating shaft 54, and a rotating cylinder 54 for routing a conductive wire connected to the induction heating coils 12 a, 12 b, 12 c to the outside of the apparatus, and rotation What is necessary is just to provide the drive means 58 provided with the rotating shaft which meshes | engages with the gearwheel 56 provided in the outer periphery of the pipe | tube 54, and transmits motive power.

  Moreover, as a form of the induction heating coil 12a, if it is an asymmetric form around the central axis (for example, a form that is not line symmetric with respect to the center line A), an L-shaped shape as shown in FIG. Such an N-type shape may be used. This is because in any case, a horizontal magnetic flux can be applied to the magnetic flux reaching the center of the induction heating member 40.

10 ......... Induction heating device, 12a, 12b, 12c ......... Induction heating coil, 14a, 14b, 14c ......... Inverter, 16 ......... IGBT, 18 ......... Diode, 20 ......... Smoothing capacitor, 21 ......... Smooth coil, 22a, 22b, 22c ......... Chopper circuit, 24 ......... IGBT, 25 ......... Smoothing capacitor, 26 ......... Converter, 28 ......... Diode, 30 ......... Power supply, 40 ………… Induction heating member, 50 ……… Rotating means, 52 ……… Nail, 54 ………… Rotating cylinder, 56 ……… Gear, 58 ……… Drive means.

Claims (3)

A circular induction heating coil arranged in an annular shape so as to face the induction heating member;
An asymmetric induction heating coil disposed opposite to the induction heating member and having an asymmetric shape around a central axis of an annulus along the shape of the circular induction heating coil on the inner peripheral side of the circular induction heating coil;
An inverter capable of individually supplying power to each induction heating coil;
An induction heating apparatus comprising:   The induction heating apparatus according to claim 1, wherein the circular induction heating coil includes a plurality of induction heating coils arranged concentrically.   The induction heating apparatus according to claim 1, further comprising a rotating unit that rotates the member to be heated around a central axis of the circular induction heating coil.

Images