JP2005276527A - Induction heating device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an induction heating device in which heat treatment of a heated material can be carried out without affecting a quartz constituting member arranged in the vicinity even in the case the heated material is heated up to high temperatures. <P>SOLUTION: The induction heating device is provided with a chamber 14 having graphite 20 to heat a wafer 24 (heated material), a heating means 16 having an induction heating coil 32 to induction heat the graphite 20, and a quartz plate 18 to separate the chamber 14 and the heating means 16, and a pyrolyzed boron nitride plate 22 (PBN plate) is installed between the graphite 20 and the quartz plate 18. Furthermore, a hole sealed by sapphire is installed at the PBN plate 22, and it is enabled to measure the temperature of the graphite 20 by a radiation thermometer 34. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an induction heating apparatus, and more particularly to an induction heating apparatus suitable for performing heat treatment of a semiconductor using induction heating.

  In the field of semiconductor manufacturing, there has been a strict demand for increasing the diameter of semiconductor wafers, improving product quality, reducing costs, and improving throughput. Under such circumstances, a lamp heating method and an induction heating method can be cited as a method for rapidly heating a semiconductor wafer (wafer).

  The lamp heating method is excellent for rapidly heating a wafer, but it is difficult to uniformly heat an object to be heated, and it is difficult to obtain a high-quality product. On the other hand, it is known that the induction heating method is capable of rapidly heating a wafer, and a technology capable of uniform heating has been developed so that a high-quality product can be obtained. .

For example, what is shown in patent document 1 is also it. In the semiconductor heat treatment apparatus described in Patent Document 1, a silicon substrate placed on SiC (SiC coated graphite) is provided in a chamber (reactor) made of quartz, and an induction heating coil for induction heating the SiC Is provided outside the chamber. In the semiconductor heat treatment apparatus described above, the SiC is held by a substrate holder having a rotation mechanism, and is configured to be rotated during heating. Further, a reflector made of alumina is provided between the chamber made of quartz and the SiC.
Japanese Patent Laid-Open No. 2003-300793

In such a semiconductor heat treatment apparatus using induction heating, with the advance of technology, the heating temperature of graphite (SiC coated graphite) has been improved for the purpose of shortening the epitaxial growth time (improving throughput). The existing heating temperature is required to be heated to 1200 ° C. or higher. However, when the heating temperature of graphite as a heating source is improved as described above, the influence on quartz and other members that receive radiant heat also appears. In particular, quartz has a strain point of about 1075 ° C., and heating to a higher temperature and rapid cooling from the higher temperature cause damage and deterioration of the quartz member. End up. Purely fused quartz has SiO ₂ as a main component, is excellent in heat resistance, translucency, and electrical insulation, is extremely chemically stable, and is suitable for application to a reaction furnace or the like. For this reason, there is a problem that quartz, which is indispensable for use in a reaction furnace or the like, can no longer be used by improving throughput.

  In the present invention, even when the graphite (object to be heated) is heated to a high temperature, the wafer (object to be heated) is heat-treated without affecting the member made of quartz disposed in the vicinity thereof. It is an object of the present invention to provide an induction heating apparatus that enables this.

  In order to achieve the above object, an induction heating apparatus according to the present invention includes a graphite for heating an object to be heated and an induction heating coil for induction heating of the graphite. An induction heating apparatus having a quartz plate separating an induction heating coil, wherein the graphite plate and the quartz plate are made of a material having anisotropy having a stronger bond in a plane direction than in a thickness direction. It is characterized by providing.

  In the induction heating apparatus, the induction heating coil may have a tubular structure capable of conducting a cooling fluid. For example, the induction heating coil having the tubular structure may be a water-cooled copper pipe in which the cooling fluid is water and the coil itself is a copper pipe.

  Furthermore, in the induction heating apparatus configured as described above, the plate made of the anisotropy material is a material in which the bond in the thickness direction is a van der Waals bond and the bond in the plane direction is a covalent bond. good.

Further, the plate made of the anisotropic material may be a pyrolytic boron nitride (hereinafter referred to as PBN) plate.
In addition, a radiation thermometer for measuring the temperature of the graphite through the quartz plate is provided, and a hole sealed with a translucent material is provided in the pyrolytic boron nitride plate, so that the radiation thermometer is made of the graphite. It is good to be able to measure temperature.

  More specifically, as an induction heating apparatus for achieving the above object, a chamber having graphite for heating a wafer, heating means having an induction heating coil for induction heating the graphite, and the chamber An induction heating apparatus including a quartz plate separating the heating means, wherein a pyrolytic boron nitride plate is provided between the graphite and the quartz plate, and the pyrolytic boron nitride plate is made of sapphire. It is preferable that a sealed hole is provided.

  In the induction heating apparatus having the above-described configuration, the induction heating apparatus having a quartz plate separating the graphite and the induction heating coil provided in the chamber has a surface direction between the graphite and the quartz plate that is larger than the thickness direction. By providing a plate made of an anisotropic material having a strong bond, the graphite is heated by induction heating, and the plate made of the anisotropic material receives radiant heat from the graphite. Even so, the propagation of heat is small in the thickness direction and widely propagated in the surface direction. For this reason, even if it is a case where a graphite and a to-be-heated material are heated to high temperature, it can suppress that a quartz plate will be heated more than a strain point.

  As described above, when the induction heating coil has a tubular structure through which a cooling fluid can be conducted, the quartz plate disposed in the vicinity of the induction heating coil can be cooled, and the quartz plate is heated above the strain point. Can be suppressed. Further, overheating of the coil itself due to radiant heat can be prevented.

The above effect can be obtained by using Van der Worth bonding as the bond in the thickness direction and covalent bonding as the bonding in the plane direction of the plate made of the anisotropic material.
Further, the above characteristics can be obtained efficiently by using a plate made of the anisotropic material as a pyrolytic boron nitride (hereinafter referred to as PBN) plate, which is a relatively thin plate. High effect can be obtained.

  In addition, a radiation thermometer for measuring the temperature of the graphite through the quartz plate is provided, and a hole sealed with a translucent material is provided in the pyrolytic boron nitride plate, so that the radiation thermometer is made of the graphite. By configuring the temperature to be measurable, the temperature of the graphite can be detected in addition to the effect of preventing the quartz plate from overheating.

  An induction heating apparatus comprising: a chamber having graphite for heating the wafer; a heating unit having an induction heating coil for induction heating the graphite; and a quartz plate separating the chamber and the heating unit. A pyrolytic boron nitride plate is provided between the graphite and the quartz plate, and the pyrolytic boron nitride plate is provided with a hole sealed with sapphire. The induction heating device can obtain the above effect.

Hereinafter, embodiments of the induction heating apparatus of the present invention will be described with reference to the drawings. The following embodiments are some embodiments according to the present invention, and the present invention is not limited to these embodiments.
FIG. 1 shows a cross-sectional view of an embodiment according to the induction heating apparatus of the present invention.
The induction heating apparatus 10 of the present embodiment includes a chamber 14 constituted by a casing 12 made of a non-conductive material or a non-magnetic material, a heating means 16, a quartz plate 18 separating the chamber 14 and the heating means 16, A graphite 20 provided in the chamber 14 and heated by the heating means 16 and a pyrolytic boron nitride plate (PBN plate) 22 that shields radiant heat from the graphite 20 are basically constructed. In the induction heating apparatus 10, a sapphire wafer (heated object) 24 as a seed substrate is placed in the chamber 14, and gallium nitride (gallium nitride: filled in the chamber 14 on the wafer 24). Epitaxial growth is promoted by depositing reactive gas components such as GaN and aluminum nitride (AlN).

  The chamber 14 is a cylindrical container, and the upper opening of the container is sealed with a quartz plate 18 to form a space separated from the heating means 16 described later. A support portion 21 is formed in the vicinity of the opening of the chamber 14, and the graphite 20 that is heated by the heating means 16 and serves as a heat source is held in the chamber 14. The support portion 21 is configured, for example, in a two-stage shape, and is preferably provided with the graphite 20 at the lower stage and the PBN plate 22 at the upper stage. The PBN plate 22 is an anisotropic material in which the bond in the plane direction is a covalent bond and the bond in the thickness direction is a van der Waals bond. The PBN plate 22 has a high thermal conductivity in the plane direction where the bond strength is strong, The thermal conductivity in the weak thickness direction is low. For this reason, even if the graphite 20 provided in the lower part of the PBN plate 22 is heated to a high temperature, the influence of heat on the member provided on the upper side of the PBN plate 22 can be suppressed.

On the lower surface side of the graphite 20, a wafer holding means 26 is provided for holding a wafer 24 that is a seed substrate for epitaxial growth and is heated by the radiant heat of the graphite 20. The wafer holding means 26 may be configured to be rotatable, for example, with the shaft portion 26a as a base point in order to uniformly heat the wafer 24. If it is desired to heat the wafer 24 rapidly, an auxiliary graphite 28 may be provided as a heating auxiliary material to increase the heating efficiency.
Further, the chamber 14 may be provided with a nozzle 30 for filling the reaction gas or extracting the internal air of the chamber 14.

  The heating means 16 is a cylindrical container having the same diameter as the chamber 14, and is configured such that the opening is closed by a quartz plate 18, as in the chamber 14. That is, the quartz plate 18 is shared by the chamber 14 and the heating means 16. In the heating means 16 configured as described above, an induction heating coil 32 as a heating source is provided in the vicinity of the opening, and by passing an electric current through the induction heating coil 32, the graphite 20 in the chamber 14 and The auxiliary graphite 28 is heated. The induction heating coil 32 may have a cooling structure, for example, a tubular structure in which a cooling fluid can be conducted. By making the induction heating coil 32 as described above, when the quartz plate 18 (see FIG. 1) disposed in the vicinity is heated by radiant heat from the graphite 20 or the like, it can be cooled, It is possible to suppress the quartz plate 18 from being overheated. Specific examples of the structure of the induction heating coil 32 include a water-cooled copper pipe in which the cooling fluid is water and the coil itself is a tubular copper pipe.

  In general, when the induction heating coils are used in close proximity, it may be difficult to control the power to be input due to the influence of mutual induction. No. 17426), the heating control of the graphite 20 and the auxiliary graphite 28 may be made possible.

  The heating means 16 may be provided with a radiation thermometer 34 for measuring the temperature of the graphite 20. The radiation thermometer measures the surface temperature of an object to be measured by measuring infrared radiation energy emitted from the surface of the object to be measured by an infrared sensor. Therefore, in such a case, it is necessary to be able to confirm the surface of the graphite 20 at least from the sensor portion of the radiation thermometer 34. Since the PBN plate 22 is an opaque material, as shown in FIG. 2, the PBN plate 22 is provided with a hole 36 for detecting the temperature of the graphite 20 by the radiation thermometer 34, and the hole has a heat resistant temperature such as sapphire. Sealing is performed with a high light-transmitting material. Further, the excess space in the casing in the heating means 16 having the above-described configuration should be made free from changes in internal atmospheric pressure by filling with an insulating material such as ceramic in order to reduce the influence of evacuation in the chamber 14. .

  In the induction heating apparatus 10 having the above configuration, the chamber 14 includes the wafer 24, the graphite 20, the PBN plate 22, the auxiliary graphite 28, and the like, and the opening is sealed with the quartz plate 18. Thereafter, the air in the chamber 14 is extracted by the nozzle 30 provided in the chamber 14 to make a vacuum state.

  An electric current is passed through the induction heating coil 32 of the heating means 16 to heat the graphite 20 and the auxiliary graphite 28 in the chamber 14 by induction heating. The graphite 20 and the auxiliary graphite 28 heated by induction heating become a heat source in the chamber 14 and heat the wafer 24 by radiant heat. At this time, the temperature distribution on the surface of the graphite 20 as the heat source is sequentially measured by the radiation thermometer 34 so that the wafer 24 is uniformly heated. When the surface temperature of the graphite 20 is different from the set temperature, the temperature distribution of the graphite 20 is controlled by controlling the induction heating coil 32. Further, the wafer holding means 26 may be rotated.

  Since the PBN plate 22 provided between the graphite 20 and the quartz plate 18 is a substance having anisotropy having van der Waals bonds in the thickness direction and covalent bonds in the plane direction. Since the thermal conductivity in the thickness direction is poor, the influence of radiant heat from the graphite 20 heated at a high temperature is suppressed from being exerted on the quartz plate 18, and the thermal conductivity in the plane direction is good, the graphite 20 is heated uniformly. Assistance is also made.

In the above-described embodiment, the upper part is the heating means 16 and the lower part is the chamber 14. The quartz plate 18 is provided at the interface between the two, and the PBN is provided between the heat source provided in the chamber 14 and the quartz plate 18. The plate 22 is provided, but a heating source is provided therein, a reaction furnace is constituted by quartz, an induction heating coil is provided outside the reaction furnace, and the heating source and the reaction furnace constituted by the quartz A PBN plate may be provided between them. That is, the structure of the induction heating apparatus of the present invention can be various as long as the induction heating apparatus includes quartz in the reaction furnace or the reaction furnace and includes a heat source that generates heat by induction heating in the reaction furnace. It can be applied.
Further, although the embodiment is described with reference to the semiconductor heat treatment, the induction heating apparatus according to the present invention can be used for other applications requiring high-temperature heating.

  In the embodiment, the structure of the induction heating coil 32 is exemplified as a water-cooled copper pipe in which the cooling fluid is water and the coil itself is a copper pipe, but the induction heating coil 32 of the present invention is limited to this. It is not a thing. For example, the cooling fluid may be a gel material made of another material or a cooling gas. Further, the coil itself that conducts the cooling fluid may be other than a copper tube as long as it is a tubular structure made of a conductive material that generates a magnetic field when energized. In addition, it cannot be overemphasized that the induction heating coil 32 of this invention contains the normal coil structure which does not have a cooling effect.

It is a sectional side view which shows embodiment which concerns on the induction heating apparatus of this invention. It is a top view which shows the structure of the pyrolysis boron nitride board (PBN board) used for embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ......... Semiconductor heat processing apparatus, 12 ......... Casing, 14 ......... Chamber, 16 ...... Heating means, 18 ......... Quartz plate, 20 ......... Graphite, 21 ...... Support part, 22 ... ... Pyrolytic boron nitride plate (PBN plate), 24 ......... Wafer, 26 ......... Wafer holding means, 28 ...... Auxiliary graphite, 30 ...... Nozzle, 32 ...... Induction heating coil, 34 ......... Radiation thermometer, 36 ......... hole.

Claims (6)

  An induction heating apparatus having a quartz plate that separates the graphite and the induction heating coil in a chamber comprising graphite for heating an object to be heated and an induction heating coil for induction heating the graphite, An induction heating apparatus characterized in that a plate made of a material having anisotropy having a stronger bond in the plane direction than in the thickness direction is provided between the graphite and the quartz plate.   The induction heating apparatus according to claim 1, wherein the induction heating coil has a tubular structure capable of conducting a cooling fluid.   3. The plate made of a material having anisotropy is a material having a bond in the thickness direction as a van der Waals bond and a bond in a plane direction as a covalent bond. Induction heating device.   The induction heating apparatus according to any one of claims 1 to 3, wherein the plate made of the anisotropic material is a pyrolytic boron nitride plate.   A radiation thermometer for measuring the temperature of the graphite through the quartz plate is provided, and a hole sealed with a light-transmitting material is provided in the pyrolytic boron nitride plate so that the radiation thermometer can control the temperature of the graphite. The induction heating apparatus according to claim 4, wherein the induction heating apparatus is configured to be measurable. An induction heating apparatus comprising: a chamber having graphite for heating a wafer; heating means having an induction heating coil for inductively heating the graphite; and a quartz plate separating the chamber and the heating means. An induction heating apparatus characterized in that a pyrolytic boron nitride plate is provided between the graphite and the quartz plate, and the pyrolytic boron nitride plate is provided with holes sealed with sapphire. .

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