Heating light source device

Abstract

To provide a heating light source device that suppresses uneven irradiation of light that is irradiated from light-emitting elements onto a substrate to be treated.SOLUTION: A heating light source device includes: a light source section having a plurality of light-emitting element areas that contain a plurality of light-emitting elements, each of the light-emitting element areas being separated from each other; a cooling unit disposed in contact with the light source section; a plurality of cooling channels formed inside the cooling unit and disposed independently each other inside the cooling unit; a first main channel connected with one end of each of the plurality of cooling channels; and a second main channel connected with the other end of each of the plurality of cooling channels. Each of the plurality of cooling channels is formed at an internal position of the cooling unit corresponding to the plurality of light-emitting element areas.SELECTED DRAWING: Figure 1A

Description

[Technical field]

[0001] The present invention relates to a light source device, and more particularly to a heating light source device for heating an object to be irradiated by irradiating light. [Background technology]

[0002] In the semiconductor manufacturing process, various heat treatments such as film formation, oxidation / diffusion, modification, and annealing are performed on substrates such as semiconductor wafers. These processes are often performed using heat treatment methods that use light irradiation, which allows for non-contact processing.

[0003] LED elements have the characteristic that their characteristics change with temperature even when the current supplied to them is the same, and the higher the temperature, the lower the brightness. For this reason, many devices that use LED elements as a light source for heating are provided with a heat sink for air cooling or a flow path for water cooling in contact with the substrate (light-emitting element substrate) on which the LED elements are mounted, in order to maintain a higher brightness of the LED elements.

[0004] In particular, for light irradiation devices that require high output and use many LED elements, such as those used in the heat treatment of semiconductor wafers, a water-cooled cooling mechanism is generally adopted, which has better heat dissipation performance than an air-cooled type. For example, the following Patent Document 1 describes an annealing device that uses LED elements as a heating light source and has a cooling mechanism that cools the LED elements by passing a cooling medium through a flow path. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Special Publication No. 2009-295953 Summary of the Invention [Problem to be solved by the invention]

[0006] For example, an apparatus for irradiating light onto a semiconductor wafer used in a semiconductor manufacturing process is expected to be able to irradiate light of the same intensity over the entire surface (particularly the main surface) of the substrate to be processed so that the entire semiconductor wafer is uniformly processed. Even when a substrate to be processed other than a semiconductor wafer (e.g., a glass substrate) is heat-treated, it is undesirable for uneven heating to occur, so it is expected to be able to irradiate light of a uniform intensity over the entire surface of the substrate to be processed.

[0007] Therefore, the present inventors have conducted extensive research into a light irradiation device capable of irradiating the entire substrate to be processed, such as a semiconductor wafer, with light more uniformly, and have found that the following problems exist.

[0008] The annealing device described in Patent Document 1 has a heating source formed of LED elements arranged over an area larger than the substrate to be treated, and a cooling medium for cooling the LED elements is supplied from a supply pipe to a flow path, flows through the flow path, and is discharged from a discharge pipe.

[0009] The annealing device is provided with two heating sources so that heating light can be applied to both the front and back principal surfaces of the substrate to be processed, and each heating source is equipped with a cooling mechanism. Each cooling mechanism is configured so that a cooling medium is supplied from one supply pipe to one flow path and discharged from one discharge pipe.

[0010] The cooling medium flows through the flow path absorbing heat generated by the LED elements, and the temperature of the cooling medium increases the further downstream it travels due to the heat it absorbs. Therefore, LED elements located in the downstream region of the flow path through which the cooling medium flows are less likely to have heat absorbed by the cooling medium than LED elements located in the upstream region of the flow path.

[0011] In other words, in a cooling mechanism that simply has a flow path for the cooling medium to flow, a large temperature difference occurs between the LED elements arranged in the upstream region of the flow path through which the cooling medium flows and the LED elements arranged in the downstream region. As a result, brightness unevenness occurs for each LED element depending on the region in which it is arranged, and irradiation unevenness occurs on the irradiated surface of the substrate to be processed.

[0012] In addition, if LED elements or other semiconductor light-emitting elements are not sufficiently cooled and are maintained at high temperatures for a long period of time, they will deteriorate faster than elements that are sufficiently cooled, and their lifespan will be shortened. In other words, in the annealing device with the above configuration, the deterioration rate of each LED element differs as it is used, and uneven irradiation and heating will gradually develop.

[0013] It is possible to consider replacing all of the LED elements when unacceptable uneven irradiation or heating occurs, but this approach would mean replacing LED elements that have not yet deteriorated much, which would increase the cost of maintaining the device.

[0014] In view of the above-mentioned problems, an object of the present invention is to provide a heating light source device in which unevenness in irradiation of light irradiated from a light-emitting element to a substrate to be processed is suppressed. [Means for solving the problem]

[0015] The heating light source device of the present invention comprises: a light source unit having a plurality of light-emitting element regions each including a plurality of light-emitting elements, the light-emitting element regions being spaced apart from each other; a cooling unit disposed in contact with the light source unit; A plurality of cooling channels formed within the cooling unit and arranged independently of each other within the cooling unit; a first main flow passage connected to one end of each of the plurality of cooling flow passages; a second main flow passage connected to the other end of each of the plurality of cooling flow passages, The cooling passages are formed at positions inside the cooling unit corresponding to the light emitting element regions, respectively.

[0016] In this specification, the term "light-emitting element region" refers to a region where multiple light-emitting elements are densely arranged, specifically, a region surrounded by a line connecting the outer edges of a group of light-emitting elements arranged so that the pitch of the light-emitting elements is 2 mm or less. Note that in this specification, the "pitch of the light-emitting elements" refers to the center-to-center distance between the light-emitting elements.

[0017] In addition, in this specification, "the cooling flow passage is formed at an internal position of the cooling unit corresponding to the light-emitting element region" means that the cooling flow passage is formed inside the cooling unit so that it is possible to distinguish which light-emitting element region is to be cooled. Note that the number of cooling flow passages that cool one light-emitting element region does not necessarily have to be one, and may be multiple.

[0018] In addition, in this specification, the term "cooling unit arranged in contact with the light source unit" includes a case where the cooling unit and the light source unit are arranged in direct contact with each other, as well as a case where they are arranged in thermal contact with each other via grease or the like for increasing thermal conductivity. Note that the light source unit is typically configured with a plurality of light-emitting elements mounted on a light-emitting element substrate, but for example, a highly thermally conductive sheet or the like may be further provided on the surface of the light-emitting element substrate opposite to the surface on which the light-emitting elements are mounted.

[0019] The cooling flow passage is a flow passage provided in the cooling unit for passing the cooling medium. The cooling medium is flowed from a first main flow passage into a plurality of cooling flow passages provided in the cooling unit. The cooling medium that has passed through each cooling flow passage flows into a second main flow passage and is discharged to the outside of the light source device. In other words, the plurality of cooling flow passages formed in the cooling unit are formed in parallel between the first main flow passage and the second main flow passage.

[0020] With the above configuration, the cooling medium is supplied directly from the first main flow path to each cooling flow path corresponding to the light-emitting element region, so that the cooling medium is supplied to the cooling flow path corresponding to each light-emitting element region in a state where it has not yet absorbed much heat. Therefore, the cooling medium is not supplied to a cooling flow path for absorbing heat of another light-emitting element region in a state where the cooling medium has absorbed heat from the light-emitting element region, so that the temperature variation of each light-emitting element region is suppressed.

[0021] Since the temperature variation in each light-emitting element region is suppressed, the variation in the luminance of the light-emitting elements is suppressed, and uneven irradiation of the heating light onto the substrate to be processed is suppressed.

[0022] The light source unit may have a single light-emitting element substrate, or may have multiple light-emitting element substrates. In the latter case, the light-emitting element substrates may be spaced apart from each other in a direction parallel to the surface of the substrate, and the regions including the multiple light-emitting elements mounted on each light-emitting element substrate may form different light-emitting element regions.

[0023] The heating light source device is The light source section may have a plurality of light-emitting element substrates divided into each of the light-emitting element regions, and may be configured such that when the light-emitting element substrate is viewed from a direction perpendicular to the main surface of the light-emitting element substrate, the light-emitting element substrate and at least a portion of the cooling flow path overlap.

[0024] With the above configuration, the heat generated in each light-emitting element region is less likely to diffuse in a direction parallel to the mounting surface of the light-emitting element substrate, and each cooling flow path is prevented from absorbing heat generated in the non-corresponding light-emitting element region. Therefore, each cooling flow path can focus on absorbing and cooling the heat generated in the corresponding light-emitting element region, and it is possible to prevent insufficient cooling in some light-emitting element regions.

[0025] The heating light source device is The cooling flow passage may have a spiral shape extending gradually from the center of the light emitting element region toward the peripheral edge thereof when viewed from a direction perpendicular to the main surface of the cooling unit.

[0026] The cooling medium flowing through the cooling flow passage absorbs heat generated by the light emitting element and propagating through the cooling unit by exchanging heat with the inner wall surface of the cooling flow passage. Therefore, in order to cool the light emitting element substrate more efficiently, it is necessary to increase the surface area of ​​the entire inner wall surface of the cooling flow passage so that more heat exchange occurs between the cooling medium and the inner wall surface of the cooling flow passage.

[0027] In addition, the central portion of the light-emitting element substrate, where the heat generated by the light-emitting element is less likely to dissipate, is more likely to become hot than the peripheral portion. Therefore, it is preferable that the cooling flow passage is formed so that the cooling medium flows gradually from the central portion of the light-emitting element region toward the peripheral portion so that the cooling medium can absorb more heat at the central portion of the light-emitting element region.

[0028] Therefore, by adopting the above-mentioned configuration, the surface area of ​​the entire inner wall surface of the cooling flow path is larger than that of a cooling flow path that only flows in one direction, and the central part of the light emitting element region can be cooled intensively, thereby averaging the temperature distribution of the entire light emitting element region.

[0029] Furthermore, in the heating light source device, The flow path width of the cooling flow path when viewed from a direction perpendicular to the main surface of the cooling unit on which the light source unit is mounted may be configured to satisfy the following formula (1), where w is the flow path width, c is the average length of the long sides of the multiple light-emitting elements, and d is the distance between the main surface of the cooling unit and the cooling flow path in the direction perpendicular to the main surface of the cooling unit. 1mm≦w≦c+2d (1)

[0030] In addition, when the cooling flow path has a spiral shape when viewed from a direction perpendicular to the main surface of the cooling unit, so that flow gradually from the central side of the light-emitting element region toward the peripheral end side, it is preferable that the cooling flow path is formed to follow the arrangement pattern of the light-emitting elements in order to cool each of the light-emitting elements arranged in the light-emitting element region.

[0031] Even if the cooling flow path in the cooling unit is configured to have a large flow path surface area, if the cooling flow path is too far from the light emitting element, the effect of the thermal resistance of the cooling unit increases, and the cooling performance decreases. For this reason, it is preferable to adjust the surface area of ​​the cooling flow path, and in particular the flow path width w of the cooling flow path, taking into account the separation distance d between the cooling flow path and the light emitting element.

[0032] The width that the heat generated by the light-emitting element spreads inside the cooling unit before it reaches the cooling flow path is described in the "Description of Embodiments" with reference to Fig. 5B, but if it is assumed that the heat is diffused isotropically inside the cooling unit, it is c+2d. In other words, in order to average the temperature distribution in the light-emitting element region, it is preferable that the flow path width of the cooling flow path is c+2d or less, and in order to improve the cooling performance, it is particularly preferable that the cooling flow path is formed directly below the light-emitting element.

[0033] However, when attempting to form a cooling unit with a very narrow cooling flow passage with a flow passage width of less than 1 mm, processing equipment and processing techniques capable of high precision processing are required, which increases manufacturing costs. Therefore, in order to suppress manufacturing costs and provide efficient cooling, it is preferable that the width w of the cooling flow passage is in the range shown in the above formula (1).

[0034] Also, although this is merely a theoretical calculation under certain conditions simulating the embodiment, it is found that the variation in temperature difference between the inner wall surface of the cooling flow path and the cooling medium relative to the flow path width (hereinafter referred to as "wall surface temperature difference") is small when the flow path width is in the range of 1 mm to 5 mm. This result also shows that the flow path width of the cooling flow path is preferably 1 mm or more, which is less likely to cause a sudden deterioration in heat dissipation efficiency due to variations in the flow path width. Details will be described in detail with reference to FIG. 6 in the section "Mode for carrying out the invention".

[0035] The above-mentioned condition for the flow path width of the cooling flow path only needs to be satisfied in the region where the cooling medium exchanges heat with the inner wall surface of the cooling unit, and does not necessarily have to be satisfied in the entire cooling flow path.

[0036] In the heating light source device, The cooling unit may be divided into a plurality of cooling members when viewed from a direction perpendicular to a main surface on which the light source portion is mounted, and the cooling flow path may be formed inside each of the cooling members. Effect of the Invention

[0037] According to the present invention, a heating light source device is realized in which unevenness in irradiation of light irradiated from a light emitting element to a substrate to be processed is suppressed. [Brief description of the drawings]

[0038] [Figure 1A] 1 is a schematic cross-sectional view of an optical heating system including a heating light source device according to an embodiment, as viewed in a Y direction. [Figure 1B] FIG. 1B is an enlarged view of the periphery of one cooling member in FIG. 1A. [Diagram 2] 1B is a diagram of the heating light source device of FIG. 1A as viewed from the -Z side. [Diagram 3] 1B is a diagram of the heating light source device of FIG. 1A as viewed from the +Z side. [Figure 4] 1 is a cross-sectional view of a cooling member as viewed from the +Z side. [Figure 5A]11 is a cross-sectional view of the cooling member when viewed in the Y direction. [Figure 5B] FIG. 5B is an enlarged view of region A1 in FIG. 5A. [Figure 6] 1 is a graph showing the correlation between a wall surface temperature difference and a flow passage width of a cooling flow passage. [Figure 7] 13 is a schematic cross-sectional view of an optical heating system including a heating light source device of another embodiment, as viewed in the Y direction. FIG. [Figure 8] 8 is a diagram of the heating light source device of FIG. 7 as viewed from the -Z side. [Figure 9] 8 is a diagram of the heating light source device of FIG. 7 as viewed from the +Z side. [Figure 10] 13 is a schematic cross-sectional view of an optical heating system including a heating light source device of another embodiment, as viewed in the Y direction. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0039] The heating light source device of the present invention will be described below with reference to the drawings. Note that the following drawings related to the heating light source device are all schematic illustrations, and the dimensional ratios and numbers in the drawings do not necessarily match the actual dimensional ratios and numbers.

[0040] Fig. 1A is a schematic cross-sectional view of an optical heating system 1 including a heating light source device 10 according to an embodiment when viewed in the Y direction, and Fig. 1B is an enlarged view of one cooling member 13a and its periphery in Fig. 1A. As shown in Fig. 1A, the optical heating system 1 includes a heating light source device 10 and a chamber 2 in which a substrate W1 to be processed is accommodated. As shown in Fig. 1A, the heating light source device 10 according to the present embodiment includes a plurality of light-emitting elements 11, a plurality of light-emitting element substrates 12, a cooling unit 13 divided into a plurality of cooling members 13a, a base 14, a first main flow path 15a, and a second main flow path 15b.

[0041] The light emitting element substrate 12 is a substrate on which a plurality of light emitting elements 11 are mounted. In this embodiment, the heating light source device 10 has a plurality of light emitting element substrates 12, and a plurality of light emitting elements 11 are mounted on each of the light emitting element substrates 12, thereby forming a light source unit 10a as a whole. In this embodiment, the cooling unit 13 is a member for cooling the light emitting element substrate 12, and is configured so that the cooling medium C1 can flow through the inside. The first main flow path 15a is a flow path for guiding the cooling medium C1 to the cooling unit 13, and the second main flow path 15b is a flow path for discharging the cooling medium C2 from the cooling unit 13 after flowing through the cooling unit 13. The base 14 is a base for fixing the cooling unit 13, but it is optional whether the heating light source device 10 includes the base 14 or not.

[0042] Fig. 2 is a diagram of the heating light source device 10 in Fig. 1A as viewed from the -Z side, and Fig. 3 is a diagram of the heating light source device 10 in Fig. 1A as viewed from the +Z side. For the sake of explanation, Fig. 3 is illustrated in a state in which the first main flow path 15a and the second main flow path 15b have been removed, and the cooling member 13a, which is not actually visible and is placed on the +Z side of the base 14, is illustrated by a dashed line.

[0043] 2, a plane parallel to the mounting surface 12a of the light-emitting element substrate 12 is defined as an XY plane, and a direction perpendicular to the XY plane is defined as a Z direction. Note that, in the following description, one of the directions in which the light-emitting elements 11 are arranged is defined as an X direction, and the other is defined as a Y direction, but in this embodiment, there is no particular distinction between the X direction and the Y direction.

[0044] In addition, when expressing a direction, if a distinction is made between positive and negative directions, a positive or negative sign is added, such as "+Z direction" and "-Z direction." When expressing a direction without distinguishing between positive and negative directions, it is simply written as "Z direction."

[0045] 1A, the chamber 2 includes a light-transmitting window 2a for taking in the heating light H1 emitted from the heating light source device 10. The chamber 2 also includes a support member 2b for supporting the substrate W1 to be processed so that the heating light H1 taken in through the light-transmitting window 2a is irradiated onto the irradiation surface W1a of the substrate W1 to be processed, which is the irradiation target.

[0046] The light emitting element 11 in this embodiment is a surface mount type LED element that is square in shape when viewed in the Z direction, and is an element with a size of 1 mm□ (mm□ indicates the length of one side of the square. The same applies below.) Furthermore, the light emitting element 11 typically has a wavelength of 365 nm to 405 nm.

[0047] The light emitting element 11 may be, for example, an LED element having a size of 1.4 mm or 2 mm, or may be an LED element having a rectangular shape when viewed in the Z direction. Furthermore, the light emitting element 11 may be an LED element other than a surface mount type, or an element other than an LED element, such as an LD element or a fluorescent element, as long as it is a light emitting element that can be used in the heat treatment of the substrate W1 to be treated.

[0048] 1A and 1B, the light emitting element substrate 12 is placed on a main surface 13b of the cooling unit 13. In this embodiment, one light emitting element substrate 12 is placed on one cooling member 13a.

[0049] 2, the light-emitting element substrate 12 has a plurality of light-emitting elements 11 arranged in the X and Y directions on the mounting surface 12a to form one light-emitting element region 11a. In this embodiment, the light-emitting element region 11a on the mounting surface 12a of the light-emitting element substrate 12 has a pitch of 2 mm between the light-emitting elements 11 in both the X and Y directions.

[0050] In order to realize a high-output light source device for heat-treating the substrate W1 to be processed, the light-emitting elements 11 need to be arranged at a narrow pitch and high density. Specifically, it is preferable that the light-emitting elements 11 are arranged at a pitch of 3 mm or less in the X and Y directions.

[0051] In this embodiment, a substrate made of aluminum nitride (AlN) is used as the light emitting element substrate 12. Examples of materials other than aluminum nitride that may be used to form the light emitting element substrate 12 include silicon carbide (SiC).

[0052] 1B and 2, the cooling member 13a, which is a part of the cooling unit 13, includes an inlet 13p to which the cooling medium C1 is supplied, and an outlet 13q to discharge the cooling medium C2 that absorbs the heat generated by the light emitting element 11 to the second main flow path 15b. The cooling member 13a in this embodiment is made of copper (Cu) that has high thermal conductivity and high heat resistance, and the cooling flow path 13r is formed by cutting the cooling member 13a. Water is typically used as the cooling medium (C1, C2), but other fluorine-based inert liquids (Fluorinert (registered trademark), Galden (registered trademark)) and the like can also be used.

[0053] The material of the cooling member 13a may be other than copper, and may be, for example, aluminum having a high heat resistance and thermal conductivity. As a method for producing the cooling member 13a having the cooling flow passage 13r by a method other than cutting, for example, a method of producing 3D image data of the cooling member 13a having the cooling flow passage 13r formed therein and producing it by 3D printing may be mentioned.

[0054] 1A, the inlets 13p formed in each cooling member 13a are connected to the cooling mechanism 15 by a first main flow path 15a, and the outlets 13q are connected to the cooling mechanism 15 by a second main flow path 15b that is different from the first main flow path 15a. In other words, the cooling flow paths 13r provided in each cooling member 13a are connected in parallel between the first main flow path 15a and the second main flow path 15b.

[0055] Fig. 4 is a cross-sectional view of the cooling member 13a when viewed from the +Z side. Fig. 5A is a cross-sectional view of the cooling member 13a when viewed in the Y direction, and Fig. 5B is an enlarged view of an area A1 in Fig. 5A. As shown in Fig. 4, the cooling member 13a includes a cooling flow path 13r that connects the inlet 13p and the outlet 13q and through which the cooling medium C1 flows.

[0056] 2, the cooling unit 13 of this embodiment is divided into a plurality of cooling members 13a each having a rectangular main surface 13b on which the light-emitting element substrate 12 is placed, but the cooling unit 13 may be divided into a plurality of cooling members 13a each having a shape other than a rectangle. For example, the cooling member 13a may have a hexagonal or octagonal main surface 13b, or may even have a sector shape.

[0057] As shown in Figure 4, when viewed in the Z direction, the cooling flow path 13r is formed so that its entirety overlaps with the light-emitting element substrate 12, and has a spiral shape that gradually extends from the central side of the light-emitting element region 11a (see Figure 2) toward the peripheral end side.

[0058] With the above configuration, the cooling medium C1 is diverted from the first main flow path 15a and supplied to multiple locations of the cooling unit 13 before absorbing heat for each cooling flow path 13r. The light-emitting element region 11a (the light-emitting element substrate 12 in this embodiment) to be cooled is located near each cooling unit 13. Therefore, each light-emitting element region 11a is cooled by the cooling medium C1, which is at a sufficiently low temperature. In other words, compared to the case where one long flow path is formed between the first main flow path 15a and the second main flow path 15b and the cooling medium C1 is supplied from one location, the temperature variation of the entire cooling unit 13 is suppressed and the temperature variation in the temperature distribution on the light-emitting element substrate 12 is suppressed.

[0059] Since the temperature variation of the plurality of light-emitting elements 11 mounted on the light-emitting element substrate 12 is suppressed, the variation in the luminance of the light-emitting elements 11 is suppressed, and uneven irradiation of the heating light H1 onto the substrate W1 to be processed is suppressed.

[0060] From this viewpoint, as long as the heating light source device 10 is provided with a plurality of light-emitting element regions 11a and the heat generated from each of the light-emitting element regions 11a is cooled by the cooling medium C1 flowing through the cooling flow paths 13r arranged in parallel, there is no limitation on the number of light-emitting element substrates 12. In other words, the heating light source device 10 may have a single light-emitting element substrate 12, and a plurality of light-emitting element regions 11a may be formed on one light-emitting element substrate 12.

[0061] For the same reason, in this embodiment, the cooling unit 13 is divided into a plurality of cooling members 13a, and the light emitting element substrate 12 is also placed on each cooling member 13a, but the number of light emitting element substrates 12 and the number of cooling members 13a may be different. For example, a configuration in which one light emitting element substrate 12 is placed across all of the cooling members 13a may be used.

[0062] In addition, in this embodiment, one cooling member 13a is formed with one inlet 13p, outlet 13q, and cooling flow path 13r, but one cooling member 13a may be formed with multiple inlets 13p, outlets 13q, and cooling flow paths 13r.

[0063] Furthermore, the cooling unit 13 does not have to be divided into a plurality of cooling members 13a, as will be described later with reference to FIG.

[0064] Next, from the viewpoint of further improving the cooling performance, a more preferable shape of the cooling flow passage 13r will be considered in detail. FIG. 5A is a cross-sectional view of the cooling member 13a when viewed in the Y direction, and FIG. 5B is an enlarged view of region A1 in FIG. 5A. The distance d between the main surface 13b on which the light emitting element substrate 12 is placed and the cooling flow passage 13r is set to 2 mm. Note that the larger the distance d between the main surface 13b and the cooling flow passage 13r, the higher the thermal resistance becomes, and the smaller the distance d, the higher the processing technology required for fabrication, which increases the cost. Therefore, the distance d between the main surface 13b and the cooling flow passage 13r is preferably 1 mm or more and 3 mm or less, and more preferably 1.5 mm or more and 2.5 mm or less.

[0065] 5B, the flow path width w of the cooling flow path 13r in this embodiment is set to 2 mm so as to satisfy the above formula (1). Here, the above formula (1) is shown again. 1mm≦w≦c+2d (1)

[0066] The shape of the light emitting element 11 mounted on the heating light source device 10 of this embodiment is a square when viewed in the Z direction, but the light emitting element 11 mounted may be rectangular when viewed in the Z direction. In this case, the value of c corresponds to the length of the long side of the light emitting element 11. When light emitting elements 11 of different sizes are mounted, the value of c is the average value of the lengths of the long sides of the light emitting elements 11.

[0067] Here, calculations were performed to confirm how the wall surface temperature difference between the inner wall surface of the cooling channel 13r and the cooling medium C1 changes with the flow path width w of the cooling channel 13r under certain conditions, and the details of the calculations are described below. Note that the results below are theoretical calculation results performed under certain conditions for consideration when designing the cooling channel 13r, and do not limit the possible range of the flow path width w of the cooling channel 13r in the present invention.

[0068] The parameters and values ​​used in the calculations are as shown in Table 1 below.

[0069] [Table 1]

[0070] The wall temperature difference is ΔT [K], and the surface area of ​​the cooling channel 13r is S [m 2 ], heat transfer coefficient is h [W / m 2 Assuming that the heat generation rate is [K] and the heat dissipation rate is [W], the wall temperature difference ΔT can be calculated by the following equation (2). ΔT = P / (h × S) (2)

[0071] The flow channel surface area S of the cooling flow channel 13r in the above formula (2) is calculated by the following formula (3) from the flow channel width w, depth b, and flow channel length L of the cooling flow channel 13r. Note that the depth b is a parameter that varies according to the flow channel width w so as to satisfy the value of the flow channel cross-sectional area X in the above Table 1. The flow channel length L is a parameter that corresponds to the length of the cooling flow channel 13r that can be formed with the flow channel width w within the range directly below (on the +Z side) of the light emitting element region 11a, assuming that the separation distance between the cooling flow channels 13r is equal to the flow channel width w. S = 2 × (w + b) × L (3)

[0072] The heat generation amount P in the above formula (2) is calculated from the drive current If and applied voltage Vf per light-emitting element 11, the total number N of light-emitting elements 11, and the light-emitting efficiency η of the light-emitting elements 11 by the following formula (4). P = If × Vf × N × (1-η) (4)

[0073] The heat transfer coefficient h in the above formula (2) is calculated by the following formula (5) using the thermal conductivity k of the cooling medium C1, the Nusselt number Nu, and the equivalent diameter de of the cross section of the cooling flow channel 13r. h = (k × Nu) / de (5)

[0074] The equivalent diameter de of the cross section of the cooling channel 13r in the above formula (5) is calculated by the following formula (6) using the flow channel cross-sectional area X of the cooling channel 13r and the total wetted perimeter Y (=2×(w+b)). de=4X / Y (6)

[0075] The Nusselt number Nu in the above equation (5) can be calculated from the friction loss coefficient f, the Reynolds number Re, and the Prandtl number Pr using the following equation (7) (Gnielinski's equation).

[0076]

number

[0077] The Reynolds number Re in the above formula (7) is calculated by the following formula (8) from the density ρ of the cooling medium C1, the flow velocity fv, and the equivalent diameter de of the cooling flow passage 13r calculated by the above formula (6). Re = (ρ × fv × de) / μ (8)

[0078] The Prandtl number Pr in the above formula (7) is calculated from the kinetic viscosity ν and thermal diffusivity α of the cooling medium C1 by the following formula (9). Pr=ν / α (9)

[0079] The friction loss coefficient f in the above formula (7) is calculated from the Reynolds number Re calculated from the above formula (8) by the following formula (10) (Blasius's formula). f=0.079Re -0.25 (10)

[0080] Fig. 6 is a graph showing the correlation between the wall surface temperature difference ΔT and the flow path width w of the cooling flow path 13r, obtained from the above formulas (2) to (10). As shown in Fig. 6, the slope is small when the flow path width w of the cooling flow path 13r is up to 5 mm, but when it exceeds 5 mm, the slope tends to become large.

[0081] In addition, as shown in FIG. 6, when the flow passage width w becomes 1.5 mm or less, the Nusselt number Nu drops sharply, and the wall temperature difference tends to increase as the flow passage width w becomes smaller.

[0082] From the above, although it is a theoretical value calculated under the above-mentioned conditions, since there is a change point (w=1.5) as shown in FIG. 6 and it is preferable to configure the wall surface temperature difference to be small from the viewpoint of exhaust heat efficiency, the flow path width w of the cooling flow path 13r is preferably 1 mm or more.

[0083] Furthermore, as described above, the narrower the flow path width w of the cooling flow path 13r, the more precise the processing technique required in the process of forming the cooling flow path 13r in the cooling unit 13. Considering these circumstances and the calculation results under the above conditions, it can be said that it is preferable to set the flow path width w of the cooling flow path 13r to 1 mm or more and 5 mm or less as a guideline.

[0084] [Another embodiment] Another embodiment will be described below.

[0085] <1> Fig. 7 is a schematic cross-sectional view of an optical heating system 1 including a heating light source device 10 of another embodiment when viewed in the Y direction. Fig. 8 is a drawing of the heating light source device 10 of Fig. 7 when viewed from the -Z side, and Fig. 9 is a drawing of the heating light source device 10 of Fig. 7 when viewed from the +Z side. As shown in Figs. 7 and 8, in the heating light source device 10 of this embodiment, the cooling unit 13 is not divided into multiple cooling members 13a as shown in Fig. 2, but is composed of a single member. A plurality of light-emitting element substrates 12 are placed on the main surface 13b of the cooling unit 13.

[0086] In the cooling unit 13 of this embodiment, as shown in Fig. 9, a plurality of inlets 13p and a plurality of outlets 13q are formed, and a plurality of cooling flow paths 13r are formed so as to connect each pair of the inlets 13p and the outlets 13q. As shown in Fig. 7, each of the cooling flow paths 13r is connected in parallel between the first main flow path 15a and the second main flow path 15b at each of the inlets 13p and the outlets 13q. In other words, each of the cooling flow paths 13r is connected in parallel between the first main flow path 15a and the second main flow path 15b.

[0087] With the above configuration, as shown in FIG. 7, the base 14 is not necessary, so that the number of components of the entire heating light source device 10 can be reduced and a simple configuration can be achieved.

[0088] 9, the cooling flow passages 13r formed in the cooling unit 13 may be formed to overlap a part of, rather than the entire light-emitting element substrate 12 when viewed in the Z direction. Also, as shown in FIG. 9, the number of light-emitting element regions 11a (here, the light-emitting element substrate 12) and the number of cooling flow passages 13r are illustrated as being the same, but the present invention does not strictly require that the number of light-emitting element regions 11a (light-emitting element substrate 12) and the number of cooling flow passages 13r be completely the same, and they may be different.

[0089] Furthermore, in each of the above-described embodiments, the cooling flow passage 13r has a spiral shape when viewed in the Z direction, gradually moving from the central side of the light-emitting element region 11a toward the peripheral end side, but the shape of the cooling flow passage 13r when viewed in the Z direction is arbitrary and may be appropriately adjusted depending on the shape of the light-emitting element region 11a and the arrangement pattern of the light-emitting elements 11.

[0090] <2> Fig. 10 is a schematic cross-sectional view of an optical heating system 1 including a heating light source device 10 of another embodiment different from that of Fig. 7, viewed in the Y direction. As shown in Fig. 10, the heating light source device 10 of the present embodiment is configured with a water distribution plate 90 having a first main flow path 15a and a second main flow path 15b formed therein.

[0091] With the above configuration, no piping space is required and the first main flow path 15a and the second main flow path 15b can be configured near the cooling unit 13 in a minimum space, thereby making it possible to reduce the size of the entire device.

[0092] The material of the water distribution plate 90 may be, for example, copper or aluminum. The first main flow path 15a and the second main flow path 15b formed in this embodiment are formed by cutting the water distribution plate 90. As a method for creating the water distribution plate 90 provided with the first main flow path 15a and the second main flow path 15b other than cutting, for example, there is a method of creating 3D image data of the water distribution plate 90 in which the first main flow path 15a and the second main flow path 15b are formed, and creating the plate by 3D printing.

[0093] Furthermore, the cooling unit 13 and the water distribution plate 90 may be integrally configured. In other words, instead of separately providing the water distribution plate 90, the heating light source device 10 of the present invention may be equipped with a cooling unit 13 in which the first main flow path 15a, the second main flow path 15b, and a plurality of cooling flow paths 13r are formed in parallel between the first main flow path 15a and the second main flow path 15b.

[0094] <3> The configuration of the heating light source device 10 described above is merely an example, and the present invention is not limited to the illustrated configurations. [Explanation of symbols]

[0095] 1: Light heating system 2: Chamber 2a: Translucent window 2b: Support member 10: Heating light source device 10a: Light source section 11: Light emitting element 11a: Light emitting element region 12: Light emitting element substrate 12a: Placement surface 13: Cooling unit 13a: Cooling member 13b: Main surface 13p: Inlet 13q: Outlet 13r: Cooling channel 14: Foundation 15 : Cooling mechanism 15a: Primary channel 15b: Second main flow path 90: Water distribution plate C1,C2: Cooling medium H1: Heating light W1: Substrate to be processed W1a: Irradiated surface

Claims

1. a light source unit having a plurality of light-emitting element regions each including a plurality of light-emitting elements, the light-emitting element regions being spaced apart from each other; a cooling unit disposed in contact with the light source unit; A plurality of cooling channels formed within the cooling unit and arranged independently of each other within the cooling unit; a first main flow passage connected to one end of each of the plurality of cooling flow passages; a second main flow passage connected to the other end of each of the plurality of cooling flow passages, A heating light source device characterized in that each of the multiple cooling flow paths is formed at an internal position of the cooling unit corresponding to a multiple of the light-emitting element regions, and when viewed from a direction perpendicular to the main surface of the cooling unit, has a spiral shape gradually extending from the central side of the light-emitting element region toward the peripheral end side.

2. The heating light source device described in claim 1, characterized in that the light source section has a plurality of light-emitting element substrates divided into each of the light-emitting element regions, and when the light-emitting element substrates are viewed from a direction perpendicular to the main surface of the light-emitting element substrates, the light-emitting element substrates overlap with at least a portion of the cooling flow path.

3. 2. The heating light source device according to claim 1, wherein a flow path width of the cooling flow path when viewed from a direction perpendicular to a main surface of the cooling unit on which the light source section is mounted satisfies the following formula (1): w is the flow path width, c is an average value of the lengths of the long sides of the plurality of light-emitting elements, and d is a distance between the main surface of the cooling unit and the cooling flow path in a direction perpendicular to the main surface of the cooling unit. 1mm≦w≦c+2d (1)

4. The heating light source device according to claim 1 or 2, characterized in that the cooling unit is divided into a plurality of cooling members when viewed from a direction perpendicular to a main surface on which the light source section is placed, and the cooling flow path is formed inside each of the cooling members.

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