Light heating device

Abstract

To provide a light heating device that can more efficiently increase the illuminance of heating light on the peripheral edge of a heating object.SOLUTION: A light heating device for irradiating a heating object with light to perform heat treatment on the heating object includes a support unit that supports the heating object, a light source unit having a plurality of first LEDs located outside the center of the heating object when viewed in a normal direction of a main surface of the heating object supported by the support unit, and a plurality of second LEDs located in an area facing the center of the heating object, and a first optical system disposed between the heating object and the light source unit in the normal direction of the main surface of the heating object, and the first optical system refracts at least a portion of the first heating light emitted by the first LEDs and directs it toward the peripheral edge of the heating object.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a light heating device that heats a processing object by irradiating the processing object with light for heating (hereinafter, for convenience, referred to as "heating light"). [Background technology]

[0002] In the semiconductor manufacturing process, various processes such as film formation, oxidation and diffusion, modification, and annealing are performed on objects to be processed, such as semiconductor wafers. In these processes, a heating method in which heating light is irradiated onto the main surface of the object to be processed is often adopted because this allows for non-contact processing. Here, the "main surface" refers to the surface that is much larger in area than the other surfaces of a plate-shaped object.

[0003] Examples of light sources for the heating light include halogen lamps and LEDs. Among these, LEDs are being adopted because they are capable of rapidly raising the temperature of the object to be heated (hereinafter, for convenience, referred to as the "object to be heated").

[0004] The light output of an LED as a single unit is typically smaller than that of, for example, a halogen lamp. Therefore, in order to irradiate the heating light required for processing to the heating object, multiple LEDs are arranged in a dense manner, as shown in Patent Document 1 below. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2018-525813 Summary of the Invention [Problem to be solved by the invention]

[0006] By using LEDs as the light source for the heating light, it is possible to heat the object at high speed. However, in recent years, there has been an increasing demand to heat the object at a higher temperature while still achieving high speed heating.

[0007] Here, the peripheral portion of the main surface of the heating object dissipates heat more easily than the central portion. Therefore, when heating the heating object, it is required to irradiate the heating light with a higher illuminance to the peripheral portion than to the central portion in order to compensate for the heat dissipation at the peripheral portion. Furthermore, assuming that the heating object is to be heated at a higher temperature, the illuminance of the heating light required at the peripheral portion of the heating object is higher than that of the conventional method.

[0008] In order to irradiate a large amount of heating light to the peripheral edge of the object to be heated and increase the illuminance of the peripheral edge, it is possible to add LEDs facing the peripheral edge. However, in conventional light heating devices, the LEDs facing the peripheral edge are arranged as close as possible (see Patent Document 1). In other words, since the LEDs are arranged in a dense state in the area facing the peripheral edge, it is difficult to add LEDs facing the peripheral edge.

[0009] Moreover, LEDs have the property that their light-emitting efficiency decreases as the temperature of the LEDs themselves increases. Therefore, for LEDs in a densely packed state, further reducing the distance between adjacent LEDs or adding LEDs to increase the heating temperature of the peripheral edge will actually reduce the intensity of the light emitted from each LED. For this reason, the above-mentioned measures cannot efficiently increase the illuminance of the heating light on the peripheral edge, and are not practically effective measures.

[0010] In view of the above circumstances, an object of the present invention is to provide a light heating device that can more efficiently increase the illuminance of heating light on the peripheral edge of an object to be heated. [Means for solving the problem]

[0011] The light heating device according to the present invention is An optical heating device for irradiating an object to be heated with light to perform a heat treatment of the object, A support unit that supports the object to be heated; A light source unit having a plurality of first LEDs positioned outside a center of the object to be heated when viewed in a normal direction of a main surface of the object to be heated supported by the support unit, and a plurality of second LEDs positioned in an area facing the center of the object to be heated; a first optical system disposed between the object to be heated and the light source unit in a normal direction to a main surface of the object to be heated; The first optical system is characterized in that it refracts at least a portion of the first heating light emitted by the first LED and causes the first heating light to proceed to a peripheral edge of the object to be heated.

[0012] Here, the peripheral edge of the object to be heated refers to a region on the main surface of the object to be heated that is 30% or less of the diameter of the main surface from the edge, and the center of the object to be heated refers to a region inside the peripheral edge within the main surface of the object to be heated.

[0013] According to the above configuration, the first heating light emitted by the first LED is efficiently irradiated to the peripheral edge of the heating object. More specifically, since the heating light emitted by the LED has low directivity, the heating light is emitted from the light-emitting surface of the LED with a predetermined spread. Therefore, assuming that the first optical system is not arranged, the first heating light includes heating light irradiated to the center side of the heating object, or heating light traveling in a direction different from the heating object. In contrast, according to the above configuration, at least a part of these heating lights is irradiated to the peripheral edge of the heating object. As a result, the heating light irradiated to the peripheral edge is increased, and the illuminance of the heating light on the peripheral edge is increased.

[0014] Moreover, the above configuration is preferable because it increases the arrangement density of the first LEDs, suppresses a decrease in the light emitting efficiency of the first LEDs, and increases the illuminance on the peripheral edge of the object to be heated.

[0015] For example, the optical member that refracts the first heating light may be a convex lens, a prism, a Fresnel lens, or the like.

[0016] In the above-mentioned light heating device, the plurality of first LEDs include an LED located outside a peripheral end of the object to be heated when viewed in the normal direction, The first optical system may refract heating light emitted by an LED located outside the peripheral edge of the object to be heated when viewed in the normal direction, and direct the heating light toward the peripheral edge of the object to be heated.

[0017] When viewed in the normal direction, the region located outside the peripheral edge of the object to be heated is different from the conventional region in which the LEDs facing the peripheral edge are densely arranged. In other words, with the above configuration, the LED arrangement density is increased, and the reduction in the luminous efficiency of the LEDs is suppressed, while more LEDs can be arranged in the light source unit.

[0018] In addition, it is assumed that the heating light emitted by the first LED located outside the peripheral edge of the heated object when viewed in the normal direction has many components traveling in a direction different from that of the heated object. In contrast, with the first optical system, the heating light emitted by the first LED is guided to the peripheral edge of the heated object, and as a result, the amount of heating light irradiated to the peripheral edge is increased.

[0019] In the above-mentioned light heating device, the first optical system is a converging optical system that is individually arranged for each LED located outside the peripheral edge of the heating object when viewed in the normal direction and that reduces a divergence angle of incident heating light, When viewed in the normal direction, the focal point of the first optical system may be located closer to the object to be heated than the center of a light emitting surface of an LED on which the first optical system is disposed.

[0020] From the viewpoint of irradiating a larger amount of the first heating light to the peripheral edge of the object to be heated, it is preferable that the first optical system is a converging optical system that reduces the divergence angle of the first heating light. Also, by disposing the focal point of the first optical system as described above, it is possible to guide most of the heating light emitted by the LED to the peripheral edge of the object to be heated.

[0021] In addition, in the above-mentioned light heating device, the first optical system is a converging optical system arranged for a plurality of LEDs positioned outside a peripheral end of the object to be heated when viewed in the normal direction, When viewed in the normal direction, the focal point of the first optical system may be located closer to the object to be heated than the center of the light emitting surfaces of the plurality of LEDs on which the first optical system is disposed.

[0022] In the above-mentioned light heating device, The plurality of first LEDs include LEDs located in an area facing a peripheral end of the object to be heated, The first optical system may be a converging optical system that reduces the divergence angle of heating light emitted by an LED located in an area facing the peripheral edge of the object to be heated.

[0023] According to the above configuration, the heating light emitted by the first LED facing the peripheral edge of the heating target is guided to the peripheral edge with a reduced divergence angle, so that the above configuration can efficiently irradiate the peripheral edge with the heating light.

[0024] As described above, since the heating light emitted by the LED has low directivity, if the first optical system is not provided, the heating light emitted by the first LED includes a component that is irradiated toward the center of the object to be heated. In the heat treatment process of the object to be heated, the temperature within the main surface of the object to be heated is typically made uniform in order to uniformly treat the main surface of the object to be heated. In this case, in order to compensate for heat dissipation at the peripheral end, the illuminance of the heating light at the peripheral end is made different from the illuminance of the heating light at the central portion, and the heating light is irradiated at a higher illuminance toward the peripheral end than the central portion.

[0025] Here, assuming that the heating temperature of the heating object is increased while the temperature in the main surface of the heating object is made uniform, it is considered necessary to increase the difference in illuminance at the peripheral end with respect to the illuminance at the central part. In contrast, according to the above configuration, the first optical system is disposed, so that the direction of the heating light toward the central part is changed and the heating light is guided toward the peripheral end. This increases the difference in illuminance between the peripheral end and the central part. In other words, the above configuration is suitable for increasing the illuminance at the peripheral end compared to the illuminance at the central part. In addition, from the viewpoint of increasing the illuminance at the peripheral end more efficiently, various optical systems that direct the heating light emitted by the first LED toward the peripheral end may be adopted as the first optical system.

[0026] In addition, in the above-mentioned light heating device, The plurality of first LEDs may be disposed in an area facing a peripheral edge of the object to be heated.

[0027] According to the above configuration, the area required for arranging the first LED is reduced compared to the above-mentioned configuration in which the first LED is arranged outside the heating object when viewed in the normal direction. In other words, the above configuration is preferable because it is easy to reduce the dimensions of the light heating device.

[0028] The light heating device is A second optical system may be provided that refracts the second heating light emitted by the second LED and directs the second heating light toward the peripheral edge of the object to be heated.

[0029] According to the above configuration, a part of the second heating light that would be irradiated toward the center of the object to be heated if the second optical system was not provided is irradiated toward the peripheral edge of the object to be heated, thereby increasing the illuminance at the peripheral edge.

[0030] Furthermore, with the above configuration, it becomes easy to increase the difference in illuminance between the peripheral edge portion and the central portion.

[0031] Furthermore, the second optical system may be a converging optical system such as a convex lens that reduces the divergence angle of the incident second heating light. By guiding the second heating light to the peripheral edge of the object to be heated in a state in which the divergence angle of the second heating light is reduced, the illuminance of the peripheral edge can be further increased.

[0032] In the above-mentioned light heating device, The light source unit includes an LED substrate having a mounting surface parallel to the main surface of the object to be heated, The LED board may have the first LED and the second LED mounted on the mounting surface.

[0033] According to the above configuration, the first LED and the second LED are arranged parallel to the main surface of the heating object. Therefore, when a cooling member such as a heat sink for cooling the first LED and the second LED is arranged on the LED substrate, the cooling member can be arranged parallel to the main surface, similar to the first LED and the second LED. Therefore, the above configuration is preferable because the design of the cooling member is easy.

[0034] The light heating device is a chamber that accommodates the support unit and the light source unit; The heating device further includes a partition plate that separates a space in the chamber in which the object to be heated is located from a space in which the light source unit is located, The first optical system may be formed integrally with the partition plate.

[0035] According to the above configuration, even when the heating object is heat-treated with the process gas introduced into the chamber or the chamber in a vacuum atmosphere, the process gas or the vacuum atmosphere is prevented from coming into contact with the first LED and the second LED. In other words, the above configuration is preferable because it can reduce the deterioration of the LED caused by the process gas, etc. Effect of the Invention

[0036] According to the present invention, there is provided a light heating device that can more efficiently increase the illuminance of heating light on the peripheral edge of the main surface of an object to be heated. [Brief description of the drawings]

[0037] [Figure 1] 1 is a side cross-sectional view showing an example of the configuration of a light heating device according to the present invention. [Figure 2A] FIG. 2 is a plan view of FIG. 1 as viewed in the Z direction. [Figure 2B] 2B is a plan view showing the arrangement of LEDs relative to the object to be heated in FIG. 2A. FIG. [Diagram 3] 2 is an enlarged view of a portion of FIG. 1. [Figure 4] 4 is a diagram showing the manner in which heating light emitted by the LED in FIG. 3 travels. [Figure 5A] 1 is a diagram illustrating the simulation conditions of Verification 1. [Figure 5B] 1 is a graph showing the results of verification 1. [Figure 6A] 13 is a diagram illustrating the simulation conditions of Verification 2. [Figure 6B] 13 is a graph showing the results of verification 2. [Figure 7A] 13 is a diagram illustrating the simulation conditions of Verification 3. [Figure 7B] 13 is a graph showing the results of Verification 3. [Figure 8A] FIG. 4 is a side cross-sectional view of a light heating device according to a second embodiment. [Figure 8B] 8B is an enlarged view of a portion of FIG. 8A. [Figure 9] FIG. 11 is a side cross-sectional view of another example of the configuration of the light heating device. [Figure 10A] FIG. 2 is a side cross-sectional view of a light heating device according to a modified example, shown similarly to FIG. 1. [Figure 10B] 10B is an enlarged view of a portion of FIG. 10A. [Figure 11] FIG. 11 is a side cross-sectional view of a modified example of the light heating device. [Figure 12] FIG. 11 is a side cross-sectional view of a modified example of the light heating device. [Figure 13A] FIG. 11 is a side cross-sectional view of a modified example of the light heating device. [Figure 13B] FIG. 12 is a plan view of FIG. 11 as viewed in the Z direction. [Figure 14] FIG. 11 is a plan view showing another example of the arrangement of LEDs. [Figure 15] FIG. 11 is a side cross-sectional view of a modified example of the light heating device. [Figure 16] FIG. 11 is a side cross-sectional view of a modified example of the light heating device. [Figure 17] FIG. 11 is a side cross-sectional view of a modified example of the light heating device. [Figure 18] 18 is a plan view of FIG. 17 as viewed in the Z direction. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] [First embodiment] Hereinafter, an embodiment of the light heating device according to the present invention will be described with reference to the drawings. Note that the following drawings are all schematic illustrations, and the dimensional ratios and numbers in the drawings do not necessarily match the actual dimensional ratios and numbers.

[0039] Fig. 1 is a side cross-sectional view showing an example of the configuration of a light heating device according to the present invention. The light heating device 1 performs a heat treatment on the object W1 to be heated by irradiating the object W1 with heating light. As shown in Fig. 1, the light heating device 1 includes a chamber 8, a support unit 2, a light source unit 3, and a first optical system 10. The light source unit 3 includes a first LED (5a, 5b), a second LED 6, and an LED substrate 7.

[0040] In the following description, an XYZ coordinate system will be referred to as appropriate, in which the normal direction of the main surface W1a of the heating object W1 is the Z direction, and the plane perpendicular to the Z direction is the XY plane. When expressing a direction, a positive or negative sign is added, such as "+X direction" and "-X direction". When expressing a direction without distinguishing between positive and negative directions, it is simply written as "X direction". In other words, in this specification, when simply written as "X direction", both "+X direction" and "-X direction" are included. The same applies to the Y direction and the Z direction.

[0041] As shown in FIG. 1, the chamber 8 includes a support unit 2 therein for supporting the object to be heated W1. The support unit 2 supports the object to be heated W1 so that the main surface W1a of the object to be heated W1 is parallel to the XY plane. As an example, the support unit 2 is configured to support the object to be heated W1 by negative pressure generated by an air intake mechanism (not shown). The support unit 2 may be configured in any way as long as it can support the object to be heated W1 with the main surface W1a parallel to the XY plane. For example, the support unit 2 may include a plurality of pin-shaped protrusions and support the object to be heated W1 by the protrusions.

[0042] In this embodiment, the heating object W1 is a semiconductor wafer such as a silicon substrate, etc. The diameter of the main surface W1a of the heating object W1 is arbitrary, but as an example, the diameter is set to 300 mm.

[0043] The first LED (5a, 5b) and the second LED 6 are arranged on a -Z side principal surface 7a of the LED substrate 7 parallel to a +Z side principal surface W1a of the heating target W1 as shown in Fig. 1. The principal surface 7a corresponds to a "mounting surface." Note that the second LED 6 is illustrated for simplicity with a portion omitted.

[0044] 1, by arranging the first LEDs (5a, 5b) on a surface (principal surface 7a) parallel to the principal surface W1a of the heating target W1, it becomes easy to design a cooling member (not shown) such as a heat sink for cooling the first LEDs (5a, 5b) even when the cooling member is arranged on the principal surface on the +Z side of the LED substrate 7. The same discussion can be applied to the second LEDs 6.

[0045] FIG. 2A is a plan view of FIG. 1 as viewed in the Z direction. For convenience of illustration, FIG. 2A shows the heating object W1 and lenses (11a, 11b) described later in a see-through manner. FIG. 2B is a plan view showing the positional relationship of the LEDs with respect to the heating object W1 in FIG. 2A. More specifically, FIG. 2B corresponds to a drawing in which the first optical system 10, the LED substrate 7, the chamber 8, and the flat glass 9 are omitted from FIG. 2A. In each drawing, the first LEDs (5a, 5b) are hatched to facilitate understanding.

[0046] In FIG. 2B, the central portion C1 of the object to be heated W1 is hatched. As shown in FIG. 2B, the first LEDs (5a, 5b) are located outside the central portion C1 of the object to be heated W1 when viewed in the Z direction. More specifically, the first LEDs (5a, 5b) include a first LED 5a arranged in an area located outside the peripheral end E1 of the object to be heated W1 when viewed in the Z direction, and a first LED 5b arranged in an area facing the peripheral end E1 of the object to be heated W1. In addition, the second LED 6 is located at a position overlapping with the central portion C1 of the object to be heated W1 when viewed in the Z direction, and is arranged in an area facing the central portion C1.

[0047] Since the first LEDs 5a are disposed outside the object to be heated W1, even if the first LEDs 5a are additionally disposed, an increase in the arrangement density of the first LEDs 5b and the second LEDs 6 can be suppressed.

[0048] Fig. 3 is a diagram showing an enlarged portion of Fig. 1. The first optical system 10 is composed of lenses 11a arranged corresponding to each of the first LEDs 5a, and lenses 11b arranged corresponding to each of the first LEDs 5b. As shown in Fig. 3, the first optical system 10 is formed on the -Z side of the flat glass 9. It is optional whether or not the lenses (11a, 11b) are arranged for all of the first LEDs (5a, 5b). For example, the lenses 11b may be arranged for some of the first LEDs 5b.

[0049] The flat glass 9 transmits the heating light emitted by the first LED (5a, 5b) and the second LED 6. Here, "transmits" means that the light transmittance for the heating light is 80% or more. The flat glass 9 is made of a glass material such as synthetic quartz glass.

[0050] As shown in Fig. 3, the lenses (11a, 11b) have a light incident surface 12 formed of a main surface on the +Z side of the flat glass 9. The lenses (11a, 11b) also have a light exit surface 13 that exhibits a convex shape on the heating target W1 side (-Z side). The light exit surfaces 13 of the lenses (11a, 11b) are disposed on the optical axes A1 of the corresponding first LEDs (5a, 5b). Here, the optical axis of the LED refers to a normal line passing through the center of the light emitting surface of the LED.

[0051] 3, the focal point F1a of the lens 11a is disposed so as to be located closer to the heating target W1 side than the optical axis A1 of the corresponding first LED 5a. Moreover, the focal point F1b of the lens 11b is disposed on the optical axis A1 of the corresponding first LED 5b.

[0052] Fig. 4 is a diagram showing the traveling manner of the heating light (L1a, L1b) emitted by the first LED (5a, 5b) and the heating light L2 emitted by the second LED 6 in Fig. 3. As shown in Fig. 4, the first LED (5a, 5b) and the second LED 6 each emit heating light to the -Z side. As an example, these heating lights have peak wavelengths in the range of 350 nm to 450 nm. The heating light L1a and the heating light L1b correspond to the "first heating light", and the heating light L2 corresponds to the "second heating light".

[0053] As described above, the focal point F1a of the lens 11a is located closer to the object to be heated W1 than the optical axis A1 of the corresponding first LED 5a. Therefore, a part of the heating light L1a incident on the lens 11a is guided to the object to be heated W1 side, as shown in FIG. 4. In other words, the lens 11a guides the heating light L1 to the object to be heated W1 side while reducing the divergence angle of the heating light L1a. This allows a large amount of the heating light L1a to be irradiated to the peripheral end E1 of the main surface W1a of the object to be heated W1.

[0054] In addition, the focal point F1b of the lens 11b is located on the optical axis A1 of the corresponding first LED 5b. Therefore, as shown in Fig. 4, the heating light L1b incident on the lens 11b is guided to the peripheral end E1 with a reduced divergence angle. As a result, a large amount of the heating light L1b is irradiated to the peripheral end E1.

[0055] The focal length of the lenses (11a, 11b) and the distance between the lenses (11a, 11b) and the object to be heated W1 in the Z direction can be adjusted as appropriate.

[0056] In the first optical system 10, the radii of curvature of the light exit surfaces 13 of the lenses (11a, 11b) may be different from each other.

[0057] In this embodiment, the lenses (11a, 11b) have a convex shape on the -Z side. However, from the viewpoint of reducing aberration and irradiating the heating target W1 with the heating light (L1a, L1b) with higher accuracy, the lenses (11a, 11b) may have a convex shape on the +Z side.

[0058] In this embodiment, an optical system such as a lens is not provided for the second LED 6. Therefore, the heating light L2 is emitted from the light-emitting surface of the second LED 6 and then irradiated to a wide area including the central part C1 of the heating object W1 (see FIG. 4). From the viewpoint of suppressing a local increase in illuminance in a part of the central part C1, it is preferable that an optical system is not provided for all or at least a part of the second LED 6 and the heating light L2 is irradiated to a wide area. Note that an optical system such as a lens may be provided for the second LED 6 according to a desired illuminance distribution, and the configuration thereof will be described later.

[0059] [Verification 1] We verified through simulation that the illuminance of the heating light irradiated to the peripheral edge E1 of the object to be heated W1 is increased by the lens 11a, whose focus F1a is positioned on the side of the object to be heated W1 relative to the optical axis A1 of the first LED 5a, and this is described below.

[0060] FIG. 5A is a diagram showing a schematic diagram of the simulation conditions of this verification. In this verification, the illuminance distribution of the heating light in the X direction among the in-plane directions of the heating target W1 having a diameter of 300 mm was verified. The first LEDs (5a, 5b) and the second LEDs 6 are both 1 mm square LEDs. Note that some of the first LEDs (5a, 5b) and some of the second LEDs 6 are omitted from the illustration in FIG. 5A. The respective arrangements of the first LEDs (5a, 5b) and the second LEDs 6 will be described below.

[0061] FIG. 5A illustrates a normal line (hereinafter, for convenience, referred to as "central axis R1") passing through the center of the main surface W1a of the object to be heated W1. In this verification, four first LEDs 5a were arranged on the -X side of the object to be heated W1. The first LEDs 5a closest to the object to be heated W1 in the X direction were arranged at a position 150 mm from the central axis R1 in the -X direction. The distance between each of the first LEDs 5a was 3 mm. The first LEDs 5a were also arranged on the +X side of the object to be heated W1 in the same manner as on the -X side. In other words, eight first LEDs 5a were arranged in the X direction.

[0062] Four first LEDs 5b were arranged in an area facing the peripheral end E1 on the -X side of the object to be heated W1. The first LED 5b closest to the central axis R1 in the X direction was arranged at a position 130 mm away from the central axis R1 in the -X direction. The distance between each of the first LEDs 5b was 3 mm. The first LEDs 5b were arranged on the +X side of the object to be heated W1 as well, similar to the -X side. In other words, eight first LEDs 5b were arranged in the X direction.

[0063] Further, 20 second LEDs 6 were arranged on the -X side from the central axis R1 in a region facing the central portion C1 of the heating target W1. The second LED 6 closest to the central axis R1 was arranged at a position 23 mm from the central axis R1 in the -X direction. The distance between each of the second LEDs 6 was 3 mm. The second LEDs 6 were also arranged on the +X side of the central axis R1 in the same manner as on the -X side. In other words, 40 second LEDs 6 were arranged in the X direction.

[0064] A lens 11a was disposed facing each of the first LEDs 5a. In other words, eight lenses 11a were disposed in the X direction. The focal point F1a of the lens 11a was disposed at a position 1 mm away from the optical axis A1 of the first LEDs 5a toward the heating target W1. The distance D1 between the first LEDs 5a and the lens 11a in the Z direction was set to 0.5 mm. The length of the lens 11a in the X direction was set to 4 mm.

[0065] The distance between the first LED (5a, 5b) and the second LED 6 and the heating target W1 in the Z direction was set to 90 mm.

[0066] Under the above conditions, the illuminance distribution in the X direction of the heating light irradiated onto the main surface W1a of the heating target W1 was simulated (for convenience, referred to as "simulation S11").

[0067] In addition, in this verification, as a comparative example, a simulation was performed of the illuminance distribution of the heating light irradiated onto the main surface W1a in a state in which the lens 11a was not disposed (for convenience, this is referred to as "simulation S12").

[0068] Fig. 5B is a graph showing the results of this verification. In Fig. 5B, the horizontal axis shows the distance in the X direction from the center of the heating object W1 as a reference, and the vertical axis shows the illuminance ratio of the heating light irradiated to the heating object W1. Note that the illuminance ratio was based on the illuminance at the end position (150 mm) of the heating object W1 in simulation S12.

[0069] 5B, it can be seen that the illuminance of the heating light irradiated to the peripheral edge of the heating target W1 is increased by disposing the lens 11a. This is thought to be because the focal point F1a of the lens 11b is disposed closer to the heating target W1 than the optical axis A1 of the first LED 5a, and the heating light L1a incident on the lens 11a is guided to the heating target W1 side.

[0070] [Verification 2] Next, we verified through simulation that the illuminance of the heating light irradiated to the peripheral end E1 of the object to be heated W1 is increased by lens 11b, whose focal point F1b is positioned on the optical axis A1 of the first LED 5b, and this is described below.

[0071] FIG. 6A is a diagram showing the simulation conditions of this verification. This verification differs from verification 1 in that the first LED 5a and the lens 11a in verification 1 are removed, and the lens 11b is arranged relative to the first LED 5b. As shown in FIG. 6A, the focal point F1b of the lens 11b is arranged on the optical axis A1 of each of the first LEDs 5b. That is, eight lenses 11b are arranged in the X direction. The distance between the first LED 5b and the lens 11b in the Z direction is the same as D1 in verification 1. The width of the lens 11b in the X direction is 4 mm. For convenience, the simulation related to this configuration is referred to as "simulation S21."

[0072] In addition, in this verification, as a comparative example, a simulation was performed of the illuminance distribution of the heating light irradiated onto the main surface W1a in a state in which the lens 11b was not disposed (for convenience, this is referred to as "simulation S22").

[0073] Fig. 6B is a graph showing the results of this verification, following Fig. 5B. Note that the illuminance ratio was based on the illuminance at the end position (150 mm) of the heating target W1 in simulation S22.

[0074] 6B, it can be seen that the illuminance of the heating light irradiated to the peripheral edge E1 of the heating object W1 is increased by providing the lens 11b. This is believed to be because the lens 11b reduces the divergence angle of the heating light L1b. More specifically, it is believed that when the lens 11b is not provided, the heating light traveling in a direction different from the heating object W1 or the heating light traveling toward the center C1 would be guided to the peripheral edge E1.

[0075] In addition, in the simulation S21, the illuminance ratio of the heating light is reduced at a position about 100 mm from the heating object W1. However, as described above, the closer to the center C1 of the heating object W1, the smaller the illuminance of the heating light required is compared to the illuminance of the heating light required at the end side of the peripheral end E1. In other words, considering that the inner region of the heating object W1 is more difficult to dissipate heat than the end side region of the heating object W1, and that the inner region is heated by heat conduction from the end side region when the end side of the peripheral end E1 is heated, it is preferable to increase the illuminance of the end side of the heating object W1 at the peripheral end E1, for example, as shown in the simulation S21.

[0076] [Verification 3] Next, the illuminance distribution of the heating light when the lens 11a and the lens 11b were arranged relative to the first LED 5a and the first LED 5b, respectively, was verified by simulation. This verification was performed under the same conditions as verification 1, except that the lens 11b was additionally arranged relative to the first LED 5b. The arrangement of the lens 11b relative to the first LED 5b was the same as the lens 11b in verification 2.

[0077] FIG. 7A is a diagram showing the simulation conditions of this verification. As shown in FIG. 7A, in this verification, the lens 11a and the lens 11b were arranged for the first LED 5a and the first LED 5b, respectively. The arrangement of the lens 11a for the first LED 5a and the arrangement of the lens 11b for the first LED 5b are the same as those described in verification 1 and verification 2. For convenience, the simulation related to this configuration is referred to as "simulation S31."

[0078] In this verification, the illuminance distribution of the heating light irradiated onto the main surface W1a was simulated in a state in which the focal point F1a of the lens 11a was positioned on the optical axis A1 of the first LED 5a (for convenience, this is referred to as "simulation S32"). Furthermore, as a comparative example, the illuminance distribution in a state in which the lens 11a and the lens 11b were not positioned was simulated (for convenience, this is referred to as "simulation S33").

[0079] Fig. 7B is a graph showing the results of this verification, following Fig. 5B. Fig. 7B shows that the illuminance of the heating light at the peripheral end E1 of the heating target W1 is increased by arranging the lenses 11a and 11b. This is believed to be because the heating light L1b emitted by the first LED 5b facing the peripheral end E1 is concentrated on the peripheral end E1 by the lens 11b. This point can be understood by comparing the simulations S32 and S33.

[0080] In addition, as is clear from the results of simulation S31, by disposing the focal point F1a of the lens 11a closer to the heating target W1 side than the optical axis A1 of the first LED 5a, the illuminance of the heating light irradiated to the peripheral edge E1 of the heating target W1 is further increased. This result is consistent with the result of verification 1.

[0081] In addition, in simulations S31 and S32, the illuminance ratio of the heating light decreases at a position about 100 mm from the object to be heated W1. The same discussion as that regarding simulation S21 in verification 2 can be applied to this point. In other words, since the inner region of the object to be heated W1 is more easily heated than the region on the edge side of the peripheral end E1, it is preferable to increase the illuminance on the edge side of the object to be heated W1 at the peripheral end E1, for example, as shown in simulations S31 and S32.

[0082] [Verification summary] In the above verification, the illuminance distribution of the heating light in the X direction was simulated, but the same discussion as above is possible for the direction parallel to the XY plane.

[0083] The above verification shows that the configuration described in the first embodiment allows more heating light to be irradiated to the peripheral edge E1 of the heating object W1. In other words, the first embodiment provides a light heating device that can more efficiently increase the illuminance of the heating light on the peripheral edge E1 of the heating object W1.

[0084] [Second embodiment] Hereinafter, a second embodiment of the light heating device according to the present invention will be described with reference to Fig. 8A and Fig. 8B, focusing on the differences from the first embodiment. Fig. 8A is a side cross-sectional view of the light heating device according to the second embodiment. Fig. 8B is an enlarged view of a part of Fig. 8A.

[0085] In the above description, the first optical system 10 is described as being composed of lenses (11a, 11b). However, the first optical system 10 may be composed of a prism 14a that refracts the heating light L1a. The prism 14a is formed on the -Z side of the flat glass 9, as shown in FIG. 8B.

[0086] 8B, the prism 14a has a light exit surface 16 inclined with respect to the main surface W1a of the heating target W1, and a light entrance surface 15 formed by the main surface on the +Z side of the flat glass 9. The light exit surface 16 of each prism 14a is disposed on the optical axis A1 of the corresponding first LED 5a.

[0087] The light exit surface 16 of the prism 14a is shaped so that the distance between the light exit surface 16 and the object to be heated W1 in the Z direction decreases as the light exit surface 16 approaches the object to be heated W1 in a direction parallel to the XY plane.

[0088] In this embodiment, a second optical system 20 that refracts the heating light L2 is disposed for some of the second LEDs 6. The second optical system 20 is composed of a prism 21 that refracts the heating light L2. The prism 21 is formed on the main surface on the -Z side of the flat glass 9, as shown in FIG.

[0089] Moreover, the prism 21 has a light exit surface 23 inclined with respect to the main surface W1a of the heating target W1, and a light entrance surface 22 formed by the main surface on the +Z side of the flat glass 9 (see FIG. 8B). The light exit surface 23 of each prism 21 is disposed on the optical axis A2 of the corresponding second LED 6.

[0090] The light exit surface 23 of the prism 21 is shaped so that the distance between the light exit surface 23 and the object to be heated W1 in the Z direction decreases as the light exit surface 23 approaches the peripheral edge E1 of the object to be heated W1 in a direction parallel to the XY plane.

[0091] 8B is a schematic diagram showing the propagation of the heating light (L1a, L1b) emitted by the first LED (5a, 5b) and the heating light L2 emitted by the second LED 6. As shown in FIG. 8B, the prism 14a refracts the incident heating light L1a toward the heating target W1. This increases the amount of heating light L1 irradiated to the peripheral end E1 of the main surface W1a of the heating target W1.

[0092] Furthermore, the prism 21 refracts the incident heating light L2 toward the peripheral end E1 of the principal surface W1a (see FIG. 8B), thereby increasing the amount of heating light L2 irradiated to the peripheral end E1 of the principal surface W1a of the heating target W1.

[0093] Although not shown in the figure, the heating light L2 emitted by some of the second LEDs 6 where the second optical system 20 is not arranged is irradiated onto a wide area including the central portion C1, thereby preventing the illuminance from becoming locally high in some areas of the central portion C1, which can be discussed in a similar manner to that described with reference to Figure 4.

[0094] The refractive index of the prisms (14a, 21) and the angle of the light exit surface (16, 23) with respect to the heating object W1 can be adjusted as appropriate.

[0095] The arrangement of the first LEDs (5a, 5b) and the second LEDs 6 can be discussed in the same manner as in the first embodiment.

[0096] In this embodiment, the first optical system 10 is configured with the prism 14a, but the first optical system 10 may be configured with, for example, a Fresnel lens. The same applies to the second optical system 20.

[0097] 9 is a side cross-sectional view of another example of the configuration of the light heating device. As shown in FIG. 9, as described in the first embodiment, a lens 11b may be disposed for the first LED 5b. As described in the second verification, this allows the heating light L1b emitted by the first LED 5b to be guided to the peripheral end E1 with the divergence angle of the heating light L1b reduced, thereby increasing the illuminance of the peripheral end E1.

[0098] Moreover, the second optical system 20 described in the second embodiment may be added to the configuration described with reference to FIG.

[0099] (Modification) Below, modified examples of the light heating device 1 will be described.

[0100] <1> The second optical system 20 may be a converging optical system that reduces the divergence angle of the heating light L2. For example, the second optical system 20 may be configured with a convex lens. Fig. 10A is a side cross-sectional view of the light heating device 1 according to a modified example shown in Fig. 1. Fig. 10B is an enlarged view of a portion of Fig. 10A. As shown in Figs. 10A and 10B, a lens 24 may be disposed relative to the second LED 6.

[0101] 10B, the focal point F2 of the lens 24 is located on the peripheral end E1 side of the object to be heated W1 with respect to the optical axis A2 of the second LED 6 on which the lens 24 is disposed. This makes it possible to guide the heating light L2 emitted by the second LED 6 to the peripheral end E1 side while reducing the divergence angle of the heating light L2.

[0102] Furthermore, considering the results of the above verification 1, it can be understood that by positioning the focus F2 of the lens 24 closer to the peripheral end E1 of the object to be heated W1 than the optical axis A2 of the second LED 6, the heating light L2 incident on the lens 24 can be guided toward the peripheral end E1.

[0103] In this modified example, the second optical system 20 may be a prism 21. However, from the viewpoint of reducing the divergence angle of the heating light L2 and increasing the amount of the heating light L2 guided to the peripheral end E1, it is preferable that the second optical system 20 is formed of a lens 24.

[0104] In addition, when the peripheral end E1 of the heating target W1 can be sufficiently heated by the heating light (L1a, L1b) emitted by the first LED (5a, 5b), there is no need for the second optical system 20. In other words, in the present invention, the second optical system 20 is an optional configuration.

[0105] <2> Fig. 11 is a side cross-sectional view of a modified example of the light heating device shown in accordance with Fig. 1. In the above, it has been described that the first LED 5a is arranged, but as shown in Fig. 11, it is optional whether or not the light source unit 3 includes the first LED 5a. It can be understood from the above verification 2 that this modified example increases the illuminance of the peripheral end E1 of the heating target W1.

[0106] The configuration in FIG. 11 does not have a first LED 5a located outside the heating target W1 when viewed in the Z direction, and the dimensions of the optical heating device 1 can be easily reduced.

[0107] <3> Fig. 12 is a side cross-sectional view of a modified example of the light heating device shown in accordance with Fig. 1. As shown in Fig. 12, a first optical system 10 may be arranged for a plurality of first LEDs 5a. More specifically, the first optical system 10 is composed of a lens 17 having a shape of a revolution body centered on a central axis R1.

[0108] The light exit surface 17a of the lens 17 is formed of a part of an ellipsoid, and the focal point (not shown) of the lens 17 is located on the central axis R1. In other words, the focal point of the lens 17 is located closer to the object to be heated W1 than the optical axis A1 of the first LED 5a, and the heating light L1a is guided so as to converge on the focal point side, thereby increasing the amount of heating light irradiated to the peripheral edge E1 of the object to be heated W1.

[0109] 12, with respect to the traveling direction of the heating light La1, a collimating lens (not shown) that converts the heating light La1 into parallel light may be disposed between the first LED 5a and the lens 17. From this viewpoint, in FIG. 12, the heating light L1a is illustrated as parallel light.

[0110] <4> Fig. 13A is a side cross-sectional view of a modified example of the light heating device 1. Fig. 13B is a plan view of Fig. 13A when viewed in the Z direction. As shown in Figs. 13A and 13B, the flat glass 9 may spatially separate the internal space of the chamber 8 into spaces S1 and S2. The space S1 is the space in which the object to be heated W1 in the chamber 8 is located, and the space S2 is the space in which the light source unit 3 in the chamber 8 is located. In this case, the flat glass 9 corresponds to the "partition plate."

[0111] 13A, the optical heating device 1 has an inlet 30 for introducing a predetermined process gas G1 into the space S1, and an exhaust outlet 31 for exhausting the process gas G1. According to the optical heating device 1 of this embodiment, a heat treatment of the heating object W1 can be performed while bringing the predetermined process gas G1 into contact with the main surface W1a of the heating object W1.

[0112] The gas species contained in the process gas G1 can be appropriately selected depending on the treatment to be performed on the heating target W1. Here, if the process gas G1 contains, for example, hydrogen chloride or ammonia, the process gas G1 may contact the first LEDs (5a, 5b) and cause the first LEDs (5a, 5b) to deteriorate or break down. However, according to this modification, the flat glass 9 spatially separates the spaces S1 and S2, preventing contact between the first LEDs (5a, 5b) and the process gas G1, and suppressing deterioration of the first LEDs (5a, 5b) due to the process gas G1. The same discussion can be made for the second LED 6.

[0113] 14 is a plan view showing another example of the arrangement of the first LEDs (5a, 5b) and the second LEDs 6. The first LEDs (5a, 5b) and the second LEDs 6 may be arranged uniformly on the main surface 7a of the LED substrate 7. "Arranged uniformly" means that the distance D2 at which the multiple LEDs are spaced apart from each other in the X direction is constant, and the distance D3 at which the multiple LEDs are spaced apart from each other in the Y direction is constant, as shown in FIG. 14. The distances D2 and D3 may be the same or different. The uniform arrangement of the first LEDs (5a, 5b) and the second LEDs 6 makes it easier to design and manufacture the LED substrate 7.

[0114] 15 is a side cross-sectional view of a modified example of the light heating device 1. In the above description, the first LED 5a is described as being arranged on the main surface 7a of the LED substrate 7 parallel to the XY plane. However, the present invention is not limited to whether the first LED 5a is arranged on a surface parallel to the XY plane.

[0115] 15, the first LED 5a may be disposed on a main surface 7b of the LED substrate 7 that is inclined with respect to the XY plane. In this modification, an example is shown in which a flat glass 9 is fixed to the LED substrate 7 via a support member 32.

[0116] In Fig. 15, some of the first LEDs 5a are arranged at an angle with respect to the XY plane, but all of the first LEDs 5a may be arranged at an angle with respect to the XY plane. Note that, in Fig. 15, the heating light L1b and the heating light L2 are omitted from the illustration.

[0117] 16 is a side cross-sectional view of a modified example of the light heating device 1. As shown in FIG. 16, the lens 11a may be disposed with respect to the first LED 5a disposed on the main surface 7b of the LED substrate 7 such that the focal point F1a is located on the optical axis A1 of the first LED 5a. According to this modified example, the heating light L1a emitted by the first LED 5a can be irradiated to the peripheral end E1 of the heating target W1 while reducing the divergence angle of the heating light L1a. The focal length of the lens 11a, etc. may be adjusted as appropriate.

[0118] <7> Fig. 17 is a side cross-sectional view showing a modified example of the light heating device 1. Fig. 18 is a plan view when Fig. 17 is viewed in the Z direction. As shown in Fig. 17, the heating target W1 may be heated while being rotated in the XY plane around the central axis R1 by the support unit 2.

[0119] In this modification, the first LED (5a, 5b) and the second LED 6 are turned on while rotating the heating target W1 around the central axis R1. By rotating the heating target W1 around the central axis R1, the heating light is uniformly irradiated in the circumferential direction of the main surface W1a of the heating target W1.

[0120] In this modification, the support unit 2 may have any configuration as long as it can rotate the heating object W1 around the central axis R1 while supporting the heating object W1. As an example, the rotation speed of the heating object W1 is set to 20 rpm to 100 rpm. Note that, although the heating object W1 rotates in this modification, the light source unit 3 and the flat glass 9 fixed to the LED substrate 7 by the light source unit 3 via the support member 32 may be rotated around the central axis R1 relative to the heating object W1.

[0121] Furthermore, for example, in this modified example, multiple second LEDs 6 may be arranged and a second optical system 20 may be arranged for some of the second LEDs 6, so that the heating light L2 emitted by some of the second LEDs 6 is guided toward the peripheral end E1, while the heating light L2 emitted by the other second LEDs 6 for which the second optical system 20 is not arranged is irradiated to a wide area including the central portion C1.

[0122] <8> In the above, the first optical system 10 or the second optical system 20 has been described as being formed integrally with the flat glass 9. However, the first optical system 10 may be formed of a member separate from the flat glass 9. The same applies to the second optical system 20.

[0123] <9> Furthermore, in the above description, the optical heating device 1 has been described as having the chamber 8. However, for example, when the process gas G1 is not introduced and the heating target W1 is heated in an air atmosphere, the chamber 8 is not necessary. In other words, it is optional whether or not the optical heating device 1 has the chamber 8.

[0124] <10> The configurations of the above embodiment and each modification can be implemented in appropriate combination. [Explanation of symbols]

[0125] 1 : Optical heating device 2: Support unit 3: Light source unit 4: Second LED 5a,5b: 1st LED 6: Second LED 7: LED board 8: Chamber 9: Flat glass 10: First optical system 11a, 11b, 17: Lenses 12,15 : Light incidence surface 13,16,17a: Light exit surface 14a: Prism 20: Second optical system 21: Prism 22: Light incidence surface 23: Light exit surface 24: Lens 30: Entrance 31: Exhaust port 32: Support member A1,A2: Optical axis C1: Central part E1: Peripheral end F1a,F1b,F2: Focus G1: Process gas L1a,L1b,L2:Heating light R1: Center axis S1,S2: Space W1: Heating object

Claims

1. An optical heating device for irradiating an object to be heated with light to perform a heat treatment of the object, A support unit that supports the object to be heated; A light source unit having a plurality of first LEDs positioned outside a center of the object to be heated when viewed in a normal direction of a main surface of the object to be heated supported by the support unit, and a plurality of second LEDs positioned in an area facing the center of the object to be heated; a first optical system disposed between the object to be heated and the light source unit in a normal direction to a main surface of the object to be heated; The optical heating device, characterized in that the first optical system refracts at least a portion of the first heating light emitted by the first LED and causes it to proceed toward a peripheral edge of the object to be heated.

2. The plurality of first LEDs include an LED located outside a peripheral end of the object to be heated when viewed in the normal direction, The optical heating device according to claim 1, characterized in that the first optical system refracts heating light emitted by an LED located outside the peripheral edge of the object to be heated when viewed in the normal direction, and causes the heating light to proceed toward the peripheral edge of the object to be heated.

3. the first optical system is a converging optical system that is individually arranged for each LED located outside the peripheral edge of the heating object when viewed in the normal direction and that reduces a divergence angle of incident heating light, The optical heating device described in claim 2, characterized in that, when viewed in the normal direction, the focus of the first optical system is located on the side of the object to be heated rather than the center of the light-emitting surface of the LED on which the first optical system is arranged.

4. the first optical system is a converging optical system arranged for a plurality of LEDs positioned outside a peripheral end of the object to be heated when viewed in the normal direction, The optical heating device described in claim 2, characterized in that, when viewed in the normal direction, the focus of the first optical system is located on the side of the object to be heated rather than the center of the light-emitting surface of the multiple LEDs in which the first optical system is arranged.

5. The plurality of first LEDs include LEDs located in an area facing a peripheral end of the object to be heated, The optical heating device according to claim 1 , wherein the first optical system is a converging optical system that reduces a divergence angle of the heating light emitted by an LED located in an area facing a peripheral edge of the object to be heated.

6. The optical heating device according to claim 5 , wherein the plurality of first LEDs are arranged in an area facing a peripheral edge of the object to be heated.

7. The optical heating device according to any one of claims 1 to 6, further comprising a second optical system that refracts the second heating light emitted by the second LED and causes it to proceed toward the peripheral end of the object to be heated.

8. The light source unit further includes an LED substrate having a mounting surface parallel to the main surface of the object to be heated, The light heating device according to any one of claims 1 to 6, wherein the LED board has the first LED and the second LED mounted on the mounting surface.

9. a chamber that accommodates the support unit and the light source unit; The heating device further includes a partition plate that separates a space in the chamber in which the object to be heated is located from a space in which the light source unit is located, The light heating device according to any one of claims 1 to 6, wherein the first optical system is formed integrally with the partition plate.

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