JPH11195616A - Heat treatment device and heat treatment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lessen fully the temperature distribution, which is generated in a material to be heated when the material is heated by lamps. SOLUTION: A plurality of spherical lamps 1 are arranged in opposition to a tabular wafer 2, the plurality of the lamps 1 are sectioned into a plurality of roughly concentrical control zones and the wafer heated by setting the light irradiation amounts of the lamps 1 in each control zone. At this time, the lamps 1 are made to arranged so that in the case where the clearances between the respective lamps 1 adjacent to each other of the lamps 1 constituting one control zone are compared with the diameter of the lamps 1, the clearances are shorter than the diameter. Thereby, the lamps 1 can be densely arranged in the circumferential directions within the control zones and irradiation of the lamps in the circumferential direction of the wafer 2 can be inhibited from being becoming uneven.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a heat treatment apparatus and a heat treatment method using a lamp, and more particularly to a heat treatment apparatus and a heat treatment method suitable for use in heat treatment of a semiconductor wafer.

[0002]

2. Description of the Related Art In order to recover crystallinity or activate a dopant after ion implantation, a heat treatment apparatus is used in which the surface of a semiconductor wafer is rapidly heated by an infrared lamp such as a halogen lamp and then rapidly cooled. An example will be described with reference to FIG. 30. A quartz glass tube H1 is provided in an apparatus housing H.
Is provided, and a semiconductor material gas is supplied into the tube H1 from a small-diameter opening at one end. The wafer 2 which is supported by the support arm 42 and is a material to be heated is inserted through the large-diameter opening at the other end of the tube H1.

In the housing H, the tube H1 is provided.
The halogen lamps 1 are provided at equal intervals in the longitudinal direction of the tube H1 at the upper and lower positions with respect to. As shown in FIG. 31, these halogen lamps 1 are generally in the form of rods provided with a reflection plate 15.

[0004]

By the way, when the wafer 2 is heated by the above-mentioned conventional heat treatment apparatus, when the wafer surface is inspected, as shown in FIG. (Up and down direction), a relatively large temperature difference (maximum 40 ° C.) is generated, and the slip of the crystal and the warpage of the wafer 2 due to the distortion become problems.

Therefore, it is conceivable to arrange the upper and lower lamps 1 in a direction orthogonal to each other. According to this, as shown in FIG. 33, the temperature distribution becomes substantially square concentric and the temperature difference is small (maximum 20 ° C.). ) Will be, but still not enough.

An object of the present invention is to provide a heat treatment apparatus and a heat treatment method capable of sufficiently reducing a temperature distribution generated in a material to be heated during lamp heating.

[0007]

According to a first or sixth aspect of the present invention, a plurality of point light sources are provided so as to face at least one surface of a plate-like material to be heated. The plurality of point light sources are divided into a plurality of substantially concentric control zones, and the material to be heated is heated by setting the light irradiation amounts of the plurality of point light sources for each control zone. . At this time, at least one control zone of the plurality of control zones is defined by a distance between adjacent point light sources of the plurality of point light sources constituting the one control zone and the point light source. When comparing the diameters of the plurality of point light sources, the plurality of point light sources are arranged so that the distance between the adjacent point light sources is smaller, and the material to be heated is heated. .

[0008] The invention according to claim 2 or 7 is characterized in that the one control zone in the invention according to claim 1 or 6 includes a control zone facing a peripheral portion of the material to be heated. I have.

According to a third or eighth aspect of the present invention, the point light source according to the first, second, sixth or seventh aspect has a glass sphere enclosing a filament, and the glass sphere is adjacent to the point sphere. When comparing the distance between the light source and the glass sphere and the diameter of the glass sphere, the plurality of glass spheres are arranged such that the distance between the adjacent glass spheres is smaller. And

According to a fourth or ninth aspect of the present invention, there is provided a glass sphere enclosing a filament containing the point-like light source according to the first, second, sixth or seventh aspect, and a glass sphere surrounding the glass sphere and forming a filament from the filament. A cylindrical reflector that reflects light, and a point adjacent to the cylindrical reflector of a specific point light source and the specific point light source in at least one of the plurality of control zones. When comparing the separation distance of the cylindrical reflection portion of the cylindrical light source with the inner diameter of the cylindrical reflection portion, the cylindrical reflection portion is arranged such that the separation distance is smaller.

According to the fifth or tenth aspect of the present invention, a plurality of spherical lamps surrounded by a cylindrical reflecting portion for reflecting light are arranged on at least one surface of the plate-shaped material to be heated. Then, the plurality of spherical lamps are divided into a plurality of substantially concentric control zones, and the material to be heated is heated by setting the light irradiation amounts of the plurality of spherical lamps for each of the control zones. At this time, in at least one control zone of the plurality of control zones, the separation distance between the cylindrical reflecting portion of the specific spherical lamp and the cylindrical reflecting portion of the spherical lamp adjacent to the specific spherical lamp and the cylinder When compared with the inner diameter of the cylindrical reflecting portion, the cylindrical reflecting portion is disposed so that the separation distance is smaller, and the material to be heated is heated.

[0012]

According to the first or sixth aspect of the present invention, the material to be heated is heated by setting the light irradiation amount of a plurality of point light sources for each control zone and heating the material to be heated. Not only can the temperature in the radial direction of the heating material be made uniform, but also at least one control zone can be separated from a plurality of point-like light sources constituting the one control zone by a distance (point-like distance) between adjacent point-like light sources. When the pitch between the light sources is 1 (ell) and the diameter of the point light source is d, the separation distance is expressed by (ld) and the diameter of the point light source is adjacent. Since the plurality of point light sources are arranged so that the distance between the respective point light sources is smaller, the plurality of point light sources can be densely arranged in the circumferential direction in the control zone, and Irradiation of the part (circumferential direction) of the material facing the one control zone is not It can be suppressed to become one.

That is, a line connecting the centers of the point light sources in the circumferential direction in the control zone (for example, the material 2 to be heated in FIG. 10)
Assuming a line that coincides with the dotted line that represents the outer edge of the shadow, the occupancy of the point light sources on that line can occupy a majority, and as a result, the point light sources are densely arranged on that line. it can.

According to the second or seventh aspect of the present invention, the point light sources can be densely arranged in the control zone facing the peripheral portion of the material to be heated, and the point light sources can be disposed on the peripheral portion of the material to be heated. Irradiation can be prevented from becoming non-uniform.

According to the third or eighth aspect of the present invention, even when the point light source has a glass bulb containing a filament, the same effect as that of the first or sixth aspect of the invention can be obtained.

According to the fourth or ninth aspect of the present invention, the point light source is constituted by a glass sphere enclosing the filament, and a cylindrical reflecting portion surrounding the glass sphere and reflecting light from the filament. Even if you do
Since the cylindrical reflecting portions can be densely arranged, it is possible to suppress non-uniform irradiation of the material to be heated.

According to the fifth or tenth aspect of the invention, the same effects as those of the fourth or ninth aspect are obtained.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] In FIG. 1, the inside of an apparatus housing H is a quartz glass plate 41 disposed in parallel.
A and 41B are vertically divided into three chambers, and a plurality of spherical halogen lamps 1 as point light sources emitting infrared light are provided in the upper chamber and the lower chamber. The intermediate chamber is a heat treatment chamber, into which the semiconductor wafer 2 as a material to be heated, which is supported by the support arm 42, is loaded.

The wafer 2 has a disk shape (FIG. 2), and a large number of halogen lamps 1 are provided in a region covering the entire plate surface of the wafer in a concentric regular hexagon shape toward the plate surface. It is. The halogen lamp 1 has a glass bulb 11 filled with an inert gas and a halogen gas (FIG. 3 (1),
The tungsten filament 12 is provided in (2)), and its light distribution is weak in the extending direction of the filament in the horizontal plane as shown in FIG. Here, the solid line in the figure is the illuminance distribution in the vertical plane, and the chain line is the illuminance distribution in the horizontal plane. The “point light source” in the present invention is preferably a light source having a substantially circular projection when viewed from the wafer 2 side.

Therefore, each of the halogen lamps 1 is shown in FIG.
As shown in FIG. 6, the arrangement direction of the filaments 12 is made different to complement the intensity of the illuminance distribution. That is, in FIG.
2 are arranged in the direction along the concentric circle, and in FIG. 6, they are arranged in the direction along the radiation.

In FIG. 1, each of the halogen lamps 1 arranged as described above is connected to an external irradiation dose setting device 3 by a wiring penetrating the wall of the device housing H.

The irradiation amount setting device 3 includes an energizing circuit 31, an energizing control circuit 32, a temperature controller 33, and a radiation thermometer 34.
The radiation thermometer 34 is installed on the bottom wall of the housing so as to measure the temperature of the central portion of the wafer 2. In this embodiment, each of the upper and lower halogen lamps 1 is concentrically divided into three zones from the center with respect to the plate surface of the wafer 2.
1 and an energization control circuit 32 (only one zone is shown).

The temperature controller 33 compares the measured temperature obtained from the radiation thermometer 34 with the set temperature of the center zone (for example, 1150 ° C.), and controls the current in the energization control circuit 32 so that the deviation becomes zero. The thyristor of the power supply unit 311 provided in the energizing circuit 31 is driven via the amplifier circuit 321 and the gate pulse circuit 322. The supply current value is fed back from the detection circuit 312 via the conversion circuit 323 of the conduction control circuit 32.

The feedback control of the power is also performed for the other remaining zones, and the set value is determined as follows. That is, a thermocouple is attached to a predetermined position corresponding to each of the above zones on a dummy wafer made of a nickel plate or a stainless steel plate, and in this state, a halogen lamp is turned on so that the temperature of each zone becomes substantially the same as the center zone. The power setting value ratio is determined as follows.

When the radiant energy density from each part when the disk-shaped material to be heated is kept at a constant temperature is calculated under a certain condition, as shown in FIG. 7, it gradually increases from the center to the outer periphery. I do. Therefore, in order to complement this, it is generally preferable that the power supplied to the circular wafer be reduced toward the center and increased toward the periphery.

In the present embodiment, the power supplied to the halogen lamp 1 in each of the surrounding zones is increased at a constant ratio based on the above-described measurement results using the thermocouples, taking the theoretical background into consideration. As shown in FIG. 8, the energy density incident on each part of the wafer 2 is increased stepwise from the central part toward the peripheral part.

By controlling the lamp irradiation amount, the wafer 2
In the upper temperature distribution, for example, as shown in FIG. 9, the temperature difference is small while leaving concentric changes (maximum 10).
° C).

The irradiation amount of the halogen lamp 1 can be controlled with higher accuracy by increasing the number of concentric zones. In this case, the temperature distribution of the wafer is further uniformed. Further, by disposing the upper and lower lamp groups so as to be shifted from each other around the center, it is possible to suppress the fluctuation of the temperature distribution at the lamp boundary. [Second to Sixth Embodiment] The arrangement density of the halogen lamps 1 can be maximized by making them concentric with a regular hexagon as in the above embodiment, but if the lamps 1 are arranged concentrically as shown in FIG. In addition, the division of the control zone becomes easy. Further, according to the shape of the wafer 2, the lamp arrangement may be square concentric as shown in FIG.

Further, at the outer peripheral portion of the wafer 2 where the incident energy density from the halogen lamp 1 needs to be increased,
If the ramp position opposing this is made closer to the wafer 2 (FIG. 12) and is gradually arranged further away from the wafer 2 toward the center, the stepwise zone control roughness can be compensated. The same effect can be achieved by reducing the wattage of the halogen lamp 1 from the outer periphery toward the center.

The halogen lamp 1 is provided with a coating 13 of gold, chromium, zirconia or the like on the inner surface or the outer surface of the rear half of the glass bulb 11, as shown in FIG. 13, or as shown in FIG. As described above, a structure in which the reflecting umbrella 14 is provided may be adopted.

In the lamp annealing apparatus having the above structure,
Halogen lamps are provided according to the shape of the wafer, and irradiation control is performed so as to compensate for the amount of radiant heat of each part of the wafer. Therefore, it is not always necessary to arrange them concentrically, and the amount of radiant heat of each part of the wafer is not only influenced by the shape of the wafer but also fluctuated by the flow of gas introduced into the heat treatment chamber. There is a need.

The lamp group may be either one of the upper and lower lamps. Seventh Embodiment By the way, in the lamp annealing apparatus having the above structure, each of the halogen lamps 1 is usually provided with a glass bulb 11 containing a filament 12 and a base 16 made of an insulator such as insulator as shown in FIG. Nari, base part 1
6 is mounted on a lamp receiver 51 (FIG. 16), and the filament 12 is heated by energizing.

At both ends of the filament 12, FIG.
(1) As shown in (2), a metal foil having a thickness of several tens of μm is provided, and this is penetrated through a wall 111 for shutting off a halogen gas sealed in the glass bulb 11 and the outside air and sealed. It is part 17.

When the filament 12 is heated, the heat is transmitted and the temperature of the sealing portion 17 rises. However, if the temperature of the sealing portion 17 becomes 250 to 350 ° C. or more, the sealing portion 17 may be oxidized and disconnected. is there. Alternatively, the halogen gas in the glass bulb 11 leaks due to the thermal expansion of the sealing portion 17, leading to a reduction in the halogen gas and introduction of the atmosphere into the lamp, which causes the filament 12 to break. Therefore, as shown in FIG. 16, the temperature rise can be prevented by providing the reflection plate 6 around the glass bulb 11 or cooling the halogen lamp 11 by air so that the temperature of the sealing portion 17 does not exceed 250 ° C. Eighth Embodiment On the other hand, at the time of heat treatment of a wafer, it is desirable to rapidly raise the wafer temperature at a rate of 250 ° C./sec and to achieve a wafer temperature distribution within ± 5 ° C. For this purpose, the halogen lamps 1 are arranged, for example, as shown in FIG. 18, and the output 1 of the halogen lamps is 300 W and the pitch l of the halogen lamps is 25 mm at the maximum.
It is good to be about. However, since the diameter of a commonly used halogen lamp is about 22 mm, there is no space for providing an effective reflector around the lamp, and when trying to cool the halogen lamp by air, the lamps become walls of each other and the air flows. May not reach, and the sealing portion may not be cooled sufficiently.

FIG. 19 shows a cooling structure of the sealing portion when the space is limited as described above. In this embodiment, FIG.
As shown in FIG. 21, the base portion of the halogen lamp 1 is divided into a base portion 18 and a base portion 19, and the base portion 18 is made of a material having good heat conductivity, and has a tapered shape whose diameter is reduced upward. It has been done. Here (FIG. 19), the taper angle θ = 2 ° 20 ′, the diameter C = 16 mm, and the height D = 12
It was a copper tapered cylinder of mm. The pitch l between the halogen lamps 1 was 25 mm. A water-cooling box 7 having a plurality of water passages 71 is provided around the base 18 (FIG. 19).
The water cooling box 6 is located at the position where the halogen lamp 1 is installed,
The halogen lamp 1 is fitted in the hole 72 corresponding to the tapered hole 72 (FIG. 22).
Are provided so as to adhere to the water-cooled box 7. At this time, the cooling water amount per halogen lamp was 200 cc / min.

The base portion 19 is made of an insulator such as a insulator, and is fixedly mounted on the lamp holder 51 with a screw portion on the outer periphery. A pin 52 is integrally provided at the lower end of the lamp holder 51, and the pin 52 is supported by a holder 53 via a spring 54.

Thus, the pin 52, the lamp receiver 51 and the halogen lamp 1 are integrally pulled by the spring force in the direction of the arrow in FIG. 19, so that the adhesion between the base 18 and the water-cooled box 7 is further improved. Then, the heat dissipation from the upper portion 18 of the base is more favorably performed, and the temperature rise of the sealing portion can be suppressed.

Here, it was examined how the temperature of the sealing portion changes with time. FIG. 23A shows a case where the halogen lamp is turned on alone, and FIG. 23B shows a case where nine halogen lamps 1 (diameter d = 22 mm) are arranged with a pitch between the lamps of 25 mm as shown in FIG. No water-cooling box, reflector, etc. were provided, and air-cooling was performed under the conditions of an air flow of 2 m ³ / min. The halogen lamp 1 has a color temperature of 2700 ° C., AC 100 V, 300
In the specification of W, the measurement was performed for the halogen lamp located at the center in (b).

As is apparent from FIG. 3, the temperature of the sealing portion rises from about 250 ° C. to about 350 ° C. in FIG.
In (b), the temperature still exceeds 400 ° C. 100 seconds after the lamp is turned on.

Next, in the above configuration (b), a water cooling box was provided in close contact with the upper part of the base, and a similar experiment was performed.
The cooling water amount per halogen lamp was set to 200 cc / min.

As a result, in the configuration of the present embodiment provided with a water-cooled box, as shown in FIG. 25, the temperature reached 150 ° C. in a steady state 120 seconds after the lamp was turned on. As described above, in the configuration of the present embodiment, the amount of heat that can be taken from the sealing portion increases, and each halogen lamp can be uniformly cooled, so that a large cooling effect can be obtained in a limited space. [Ninth and Tenth Embodiments] In the eighth embodiment, the shape of the base portion 18 is not limited to the cylindrical tapered shape, but may be a square tube (FIG. 2).
6), and other shapes such as a cylinder (FIG. 27) are also possible. The water-cooled box can also be processed according to the shape of the base.

The same experiment as described above was conducted for the case where the shape of the upper portion of the base 18 was cylindrical as shown in FIG. In the halogen lamp 1, as shown in FIG. 28, the upper portion 18 of the base was a copper cylinder having a diameter B = 16 mm and a height D = 12 mm.

In this case, however, the upper part 18 of the base and the water-cooled box 7
Do not adhere to each other, and a gap G is generated between the water-cooled box 7. Therefore, the gap G for obtaining a sufficient cooling effect was determined by the following heat passing equation.

[0044]

(Equation 1) L: Pipe length K: Heat transfer rate Q: Heat passing amount

[0045]

(Equation 2) α: heat transfer coefficient of fluid γ _i : outermost radius of pipe ρ _m : γ _m / γ _m-1 (γ _m : radius of each pipe) λ: thermal conductivity of each pipe Formulas (1) and (2) above From the calculation, the gap G required for the sealing portion to be 250 ° C. or less was calculated.
Was found to be 0.02 mm or less.

An experiment was conducted with the gap G set to 0.02 mm or less and the amount of cooling water and the specifications of the lamp as in the above embodiment. As a result, as shown in FIG. 29, a steady temperature of 220 ° C. was reached 18 seconds after the lamp was turned on, indicating that a sufficient cooling effect was obtained.

As described above, according to the lamp annealing apparatus of the present embodiment, it is possible to uniformly heat various shapes of plate-like materials to be heated. To play.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an apparatus according to a first embodiment.

FIG. 2 is a plan view showing an arrangement of the halogen lamp according to the first embodiment.

FIGS. 3A and 3B are side views of the halogen lamp according to the first embodiment.

FIG. 4 is a diagram showing light distribution characteristics of the halogen lamp according to the first embodiment.

FIG. 5 is a diagram showing a filament direction of the halogen lamp according to the first embodiment.

FIG. 6 is a view showing a filament direction of the halogen lamp according to the first embodiment.

FIG. 7 is a diagram showing a radiant energy density of a disk wafer according to the first embodiment.

FIG. 8 is a view showing an incident energy density with respect to a disk wafer according to the first embodiment.

FIG. 9 is a plan view showing a temperature distribution of the disk wafer according to the first embodiment.

FIG. 10 is a plan view showing an arrangement of a halogen lamp according to a second embodiment.

FIG. 11 is a plan view showing an arrangement of a halogen lamp according to a third embodiment.

FIG. 12 is a sectional view of an apparatus main body showing another arrangement of the halogen lamp according to the fourth embodiment.

FIG. 13 is a side view of a halogen lamp according to a fifth embodiment.

FIG. 14 is a perspective view of a halogen lamp according to a sixth embodiment.

FIG. 15 is an exploded view of a halogen lamp according to a seventh embodiment.

FIG. 16 is a side view of a halogen lamp according to a seventh embodiment.

FIG. 17 is an enlarged view of a glass ball according to a seventh embodiment.

FIG. 18 is a view showing an arrangement example of a halogen lamp according to an eighth embodiment.

FIG. 19 is a partial sectional view of a lamp annealing apparatus according to an eighth embodiment.

FIG. 20 is an exploded view of a halogen lamp according to an eighth embodiment.

FIG. 21 is a perspective view of a halogen lamp according to an eighth embodiment.

FIG. 22 is a partial sectional view of a water-cooled box according to an eighth embodiment.

FIGS. 23A and 23B are diagrams showing a temperature change of a sealing portion according to an eighth embodiment. FIGS.

FIG. 24 is a diagram showing a configuration of an apparatus used for measuring a temperature change of a sealing portion according to an eighth embodiment.

FIG. 25 is a diagram showing a temperature change of a sealing portion according to the eighth embodiment.

FIG. 26 is a perspective view of a halogen lamp according to a ninth embodiment.

FIG. 27 is a perspective view of a halogen lamp according to a tenth embodiment.

FIG. 28 is a side view of the halogen lamp according to the tenth embodiment.

FIG. 29 is a diagram showing a temperature change of a sealing portion according to the tenth embodiment.

FIG. 30 is a sectional view of an apparatus main body according to a conventional example.

FIG. 31 is a perspective view of a halogen lamp according to a conventional example.

FIG. 32 is a plan view showing a temperature distribution of a disk wafer according to a conventional example.

FIG. 33 is a plan view showing a temperature distribution of a disk wafer according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Halogen lamp (point light source) 2 ... Wafer (material to be heated) 3 ... Irradiation amount setting circuit (irradiation amount setting means) 31 ... Power supply circuit 32 ... Power supply control circuit 33 ... Temperature controller 34 ... Radiation thermometer

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Shoji Hirose 14 Iwatani, Shimowasumi-cho, Nishio-shi, Aichi Japan Auto Parts Research Institute

Claims (10)

[Claims] A plurality of point light sources arranged to face at least one surface of a plate-shaped material to be heated, and the plurality of point light sources are divided into a plurality of substantially concentric control zones; An irradiation amount setting unit that sets an irradiation amount of the plurality of point light sources for each control zone, and a heat treatment apparatus that heats the material to be heated by light emitted by the plurality of point light sources, At least one control zone of the plurality of control zones is a distance between adjacent point light sources of the plurality of point light sources constituting the one control zone and the diameter of the point light sources. The heat treatment apparatus according to claim 1, wherein the plurality of point light sources are arranged such that the distance between the adjacent point light sources is smaller when compared. 2. The heat treatment apparatus according to claim 1, wherein the one control zone includes a control zone facing a peripheral portion of the material to be heated. 3. The point-like light source has a glass sphere enclosing a filament, and the distance between the glass sphere and the glass sphere of the adjacent point-like light source is compared with the diameter of the glass sphere. The heat treatment apparatus according to claim 1, wherein the plurality of glass spheres are arranged such that a distance between the adjacent glass spheres is smaller. 4. The point-like light source comprises a glass sphere enclosing a filament, and a cylindrical reflecting portion surrounding the glass sphere and reflecting light from the filament, and at least one of the plurality of control zones. In one control zone, the distance between the cylindrical reflector of the specific point light source and the cylindrical reflector of the point light source adjacent to the specific point light source is compared with the inner diameter of the cylindrical reflector. 3. The heat treatment apparatus according to claim 1, wherein the cylindrical reflecting portion is disposed such that the separation distance becomes smaller in the case. 5. A plurality of spherical lamps which are surrounded by a cylindrical reflecting portion for reflecting light and are arranged opposite to a plate-like material to be heated.
An irradiation amount setting unit configured to divide the plurality of spherical lamps into a plurality of substantially concentric control zones, and to set a light irradiation amount of the plurality of spherical lamps for each of the control zones; A heat treatment apparatus that heats the material to be heated by light that is generated, wherein at least one control zone of the plurality of control zones is adjacent to a cylindrical reflector of a specific spherical lamp and the specific spherical lamp. When the distance between the cylindrical reflecting portion of the spherical lamp and the inner diameter of the cylindrical reflecting portion are compared, the cylindrical reflecting portion is arranged such that the separating distance is smaller. Heat treatment equipment. 6. A plurality of point-like light sources are arranged opposite to at least one surface of a plate-shaped material to be heated, and the plurality of point-like light sources are divided into a plurality of substantially concentric control zones. A heat treatment method for heating the material to be heated by setting light irradiation amounts of the plurality of point light sources for each zone, wherein at least one control zone of the plurality of control zones is controlled by the one control zone. When comparing the distance between the adjacent point light sources of the plurality of point light sources constituting the zone and the diameter of the point light sources, the distance between the adjacent point light sources is smaller than the distance between the adjacent point light sources. A heat treatment method, wherein the plurality of point light sources are arranged so as to reduce the temperature, and the material to be heated is heated. 7. The heat treatment method according to claim 6, wherein the one control zone includes a control zone facing a peripheral portion of the material to be heated. 8. The point-like light source has a glass sphere enclosing a filament, and the distance between the glass sphere and the glass sphere of the adjacent point-like light source is compared with the diameter of the glass sphere. 8. The heat treatment method according to claim 6, wherein the plurality of glass spheres are arranged such that a distance between the adjacent glass spheres is smaller. 9. The point-like light source is constituted by a glass sphere enclosing a filament, and a cylindrical reflecting portion surrounding the glass sphere and reflecting light from the filament. In at least one control zone, the distance between the cylindrical reflector of the specific point light source and the cylindrical reflector of the point light source adjacent to the specific point light source is compared with the inner diameter of the cylindrical reflector. If you do
The heat treatment method according to claim 6, wherein the cylindrical reflecting portion is arranged so that the separation distance is smaller. 10. A plurality of spherical lamps surrounded by a cylindrical reflecting portion for reflecting light are arranged on at least one surface of a plate-shaped material to be heated, and the plurality of spherical lamps are substantially concentric. A heat treatment method for heating the material to be heated by dividing into a plurality of control zones and setting a light irradiation amount of the plurality of spherical lamps for each control zone, wherein at least one of the plurality of control zones In one control zone, when comparing the separation distance between the cylindrical reflecting portion of the specific spherical lamp and the cylindrical reflecting portion of the spherical lamp adjacent to the specific spherical lamp and the inner diameter of the cylindrical reflecting portion, A heat treatment method comprising: arranging the cylindrical reflecting portion so that a separation distance is smaller; and heating the material to be heated.