Light irradiation device

Abstract

To provide a light irradiation device in which an irradiation variation of a light irradiated to a processed substrate from an LED element is suppressed without increasing the size of a whole of a device.SOLUTION: A lighting irradiation device comprises: a chamber; a support member that supports a processed substrate in the chamber; an LED substrate that is arranged on a main surface of the LED substrate so as to be opposite to the processed substrate; and a plurality of LED elements that is arranged so as to emit a light toward the main surface of the processed substrate supported by the support member. When a region where an LED element of the LED substrate is divided into a plurality of regions in a concentric circular, the plurality of regions contains: a first region at the outermost side; a second region that is a region separated from the first region in an inner side of the first region, and in which a value obtained by dividing a total value of a power supplied with an area is smaller than the first region; and a third region that is a region nipped with the first and second regions, and in which a value obtained by dividing the total value of the power supplied with the area is smaller than the second region.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a light irradiation device, and more particularly to a light irradiation device that uses an LED element as a light source and irradiates a substrate to be processed with light. [Background technology]

[0002] In the semiconductor manufacturing process, various heat treatments such as film formation, oxidation and diffusion, modification, and annealing are performed on substrates to be processed such as semiconductor wafers, and these treatments often use a heat treatment method using light irradiation that allows non-contact treatment.The following Patent Document 1 discloses a light heating device that heat-treats semiconductor wafers using light emitted from LED elements. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Special Publication No. 2018-523305 Summary of the Invention [Problem to be solved by the invention]

[0004] An apparatus for irradiating light onto a semiconductor wafer used in a semiconductor manufacturing process is expected to be able to irradiate the entire surface (particularly the main surface) of the semiconductor wafer with light of the same intensity so that the entire semiconductor wafer is processed uniformly.

[0005] The present inventors have therefore conducted extensive research into a light irradiation apparatus capable of irradiating a substrate to be processed, such as an entire semiconductor wafer, with more uniform light, and have found that there are problems as described below. The following describes the problems with the apparatus with reference to the drawings.

[0006] Fig. 9 is a schematic cross-sectional view of a conventional light irradiation device 100 as viewed in the Y direction. As shown in Fig. 9, the light irradiation device 100 includes a chamber 101 and a plurality of LED elements 102 arranged on an LED substrate 103. The chamber 101 also includes a light-transmitting window 101a for introducing light emitted from the LED elements 102 into the inside, and a support member 104 for supporting a substrate W1 to be processed inside.

[0007] In the following description, the direction in which the LED substrate 103 and the substrate W1 to be processed face each other is defined as the Z direction, the direction in which the support member 104 faces each other is defined as the X direction, and the direction perpendicular to the X and Z directions is defined as the Y direction. Since the arrangement of the LED elements 102 in the light irradiation device 100 is the same when viewed in the X direction and when viewed in the Y direction, only the structure when viewed in the Y direction will be described unless otherwise necessary.

[0008] In this specification, when expressing a direction, if there is a need to distinguish between positive and negative directions, the direction is described with a positive or negative sign, such as "+Z direction" and "-Z direction." When expressing a direction without distinguishing between positive and negative directions, the direction is simply described as "Z direction."

[0009] 9, the light emitted from the LED elements 102 and reaching the peripheral end W1e side of the substrate W1 is less than that reaching the central portion W1c side of the substrate W1. As a result, the light intensity at the peripheral end W1e side is significantly lower than that at the central portion W1c side.

[0010] Therefore, the above-mentioned Patent Document 1 discloses a configuration in which LED elements 102 are arranged over a range wider than the area of ​​the LED substrate 103 facing the substrate W1 to be processed, in order to suppress temperature variations between the central portion W1c and the peripheral portion W1e of the substrate W1 to be processed.

[0011] Fig. 10 is a schematic cross-sectional view of a conventional light irradiation device 100 having a different configuration from that shown in Fig. 9, viewed in the Y direction. The light irradiation device 100 shown in Fig. 10 irradiates the central part W1c side and the peripheral part W1e side of the substrate W1 to be processed in the same manner with light emitted from the LED elements 102, so that the substrate W1 can be uniformly irradiated with light over the entire substrate W1 to be processed.

[0012] However, the light irradiation device 100 shown in FIG. 10 requires a larger chamber 101 and LED substrate 103 than the light irradiation device 100 shown in FIG. 9, which results in an increase in the size of the entire device.

[0013] Therefore, as a method for suppressing the decrease in light intensity of the peripheral edge W1e, it is conceivable to arrange the LED elements 102 at a high density only in the area where the LED elements 102 that irradiate light toward the peripheral edge W1e of the substrate to be processed W1 are arranged, thereby increasing the intensity of light irradiated around the peripheral edge W1e of the substrate to be processed W1.

[0014] Fig. 11 is a schematic cross-sectional view of a conventional light irradiation device 100 having a different configuration from those in Fig. 9 and Fig. 10, viewed in the Y direction. In the light irradiation device 100 shown in Fig. 11, since there is a large amount of overlapping light on the peripheral end W1e side of the substrate W1 to be processed, a decrease in the intensity of the light irradiated to the peripheral end W1e of the substrate W1 to be processed is suppressed.

[0015] However, in the light irradiation device 100 shown in Fig. 11, although the device as a whole is not large, an area W1d is formed between the central part W1c and the peripheral part W1e, where the light intensity is higher than that of the central part W1c and the peripheral part W1e due to the increase in the amount of overlapping light. The relationship between the relative intensities of the light irradiated to the substrate W1 to be processed is described in detail with reference to Fig. 6 in [Mode for carrying out the invention].

[0016] If the light intensity on the peripheral end W1e side is only slightly lower than that on the central end W1c side, a countermeasure can be taken, such as using an optical member such as a mirror to compensate for the decrease in light intensity with reflected light. However, it is difficult to reduce the light intensity only in a partial region inside the peripheral end W1e, and if an optical member that blocks or scatters some of the light is used as a countermeasure, it may actually worsen the uniformity of the light intensity distribution.

[0017] In view of the above problems, the present invention has an object to provide a light irradiation device that suppresses uneven irradiation of light irradiated from LED elements to a substrate to be processed, without increasing the size of the entire device. [Means for solving the problem]

[0018] The light irradiation device of the present invention comprises: A light irradiation device that irradiates a substrate to be processed with light, a chamber for accommodating the substrate to be processed; a support member for supporting the substrate to be processed within the chamber; an LED substrate disposed opposite the substrate to be processed supported by the support member; a plurality of LED elements arranged on a main surface of the LED substrate so as to emit light toward a main surface of the substrate supported by the support member; When the region in which the LED elements of the LED substrate are arranged is divided into a plurality of concentric regions, the plurality of regions are: An outermost first region; a second region that is inside the first region and separated from the first region, and has a value obtained by dividing a total value of power supplied to the second region by an area of ​​the second region that is smaller than that of the first region; The present invention is characterized in that it includes a third region sandwiched between the first region and the second region, the total value of the power supplied thereto divided by the area of ​​which is smaller than that of the second region.

[0019] In this specification, the term "the substrate to be processed and the LED substrate facing each other" refers not only to cases where their respective main surfaces face each other directly, but also to cases where they face each other via a member that transmits light emitted from the LED elements, such as a transparent window formed in the wall of the chamber.

[0020] The luminance of the region increases as the total power supply divided by the area increases. In other words, with the above configuration, the luminance of the LED elements in each region becomes: first region > second region > third region.

[0021] If the brightness of the region where light is irradiated around the peripheral edge is simply increased, as described above with reference to Fig. 11, a region where light with high intensity is irradiated will be generated. Therefore, by providing a third region between the first region and the second region, which has a lower brightness than either region, the light intensity is prevented from becoming high in the region where the light emitted from the LED element arranged in the first region and the light emitted from the LED element arranged in the second region overlap. Therefore, the uniformity of the light irradiated to the main surface of the substrate to be processed can be improved.

[0022] Furthermore, with the above configuration, it is possible to reduce the size of the chamber or LED substrate by adjusting the area ratio of each area and the power supplied to each area, regardless of the size of the LED element arrangement area. In other words, the entire device can be made smaller.

[0023] The light irradiation device is the number of the LED elements per unit area in the second region is smaller than the number of the LED elements per unit area in the first region; The number of the plurality of LED elements per unit area in the third region may be smaller than the number of the plurality of LED elements per unit area in the second region.

[0024] The higher the number of LED elements per unit area, i.e., the higher the arrangement density, the more LED elements that irradiate the same area of ​​the main surface of the substrate supported by the support member. In other words, the above configuration increases the intensity of the light emitted from the LED elements in the first area and irradiated around the peripheral edge of the substrate. Therefore, for the same reason as above, the uniformity of the light intensity distribution irradiated over the entire main surface of the substrate can be improved.

[0025] The light irradiation device is a cooling member provided on a surface of the LED substrate opposite to a surface on which the LED elements are mounted, the cooling member having an inlet for introducing a cooling medium for cooling the LED elements into the inside of the LED substrate, an outlet for discharging the cooling medium to the outside of the LED substrate, and a flow path connecting the inlet and the outlet so that the cooling medium passes from the inlet through the first region, the second region, and the third region of the LED substrate in this order; The cooling medium may be supplied from the inlet of the LED substrate into the flow path.

[0026] LED elements have the characteristic that, even if the supplied power is the same, the characteristics vary with temperature, and the higher the temperature, the lower the brightness. Therefore, when it is desired to uniformly irradiate light onto a substrate to be processed using a light irradiation device that uses LED elements as a light source, it is preferable to adjust the temperature distribution of the entire LED elements to be uniform so that all the LED elements light up at the desired brightness.

[0027] Since the temperature of the LED elements depends on the power supplied per unit area, the temperatures of the LED elements arranged in the first area, second area, and third area will be lower in that order. Therefore, in order to make the temperature distribution of the entire LED elements uniform, it is necessary to focus on cooling the LED elements arranged in the first area.

[0028] In addition, in many light irradiation devices that use LED elements as light sources, cooling members with air-cooling heat sinks and water-cooling channels are provided on the LED board in order to maintain higher brightness. 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-cooling cooling mechanism is generally adopted, which has better heat dissipation performance than an air-cooling type.

[0029] The cooling medium flowing from the supply mechanism into the inlet gradually increases in temperature as it flows through the flow path while absorbing heat generated by the LED elements, and the ability to absorb heat decreases as it approaches the outlet. Therefore, it is preferable that the flow path is configured so that the cooling medium flowing into the inlet immediately flows through the area that needs to be cooled most. In the present invention, for example, water or a fluorine-based inert liquid can be used as the cooling medium.

[0030] With the above configuration, the cooling medium absorbs more heat in the first region where the power per unit area is high, and therefore the first region where the temperature is the highest is cooled intensively, improving the uniformity of the temperature distribution over the entire LED substrate.

[0031] In addition, the power supplied per unit area is greatest in the first region, followed by the second region and the third region, and so the temperatures increase in this order. Therefore, by passing the cooling medium through the first region, the second region and the third region in that order, the higher the temperature of the region, the more heat is absorbed by the cooling medium, and the uniformity of the overall temperature distribution is improved.

[0032] In addition, the flow path may include a path that is connected by a water pipe outside the LED substrate from the inlet to the outlet. For example, if each region is formed concentrically from the peripheral end side in the order of the first region, the third region, and the second region, when the entire flow path is formed in the LED substrate in the above order, the third region must be passed when going from the first region to the second region. Therefore, in order to realize a flow path that connects the first region, the second region, and the third region in that order, the flow path may include a water pipe that connects the first region and the second region outside the LED substrate.

[0033] It is also possible to form a bypass path from the first region to the second region in a part of the third region so that the cooling medium flows in the above-mentioned order. In this specification, the bypass path is provided not for cooling the element but solely for the purpose of movement between regions, so that the above configuration also means that the cooling medium flows from the first region to the second region.

[0034] In the above light irradiation device, The material of the LED substrate may be mainly composed of aluminum nitride or silicon nitride.

[0035] In this specification, the term "major component" refers to the material that is present in the largest proportion.

[0036] With the above configuration, the heat generated from the LED element can be efficiently transferred to the cooling medium flowing through the flow path.

[0037] In the above light irradiation device, The LED substrate may have a hole connecting the main surfaces of the LED substrate.

[0038] With the above configuration, a radiation thermometer for measuring the temperature of the main surface of the substrate to be processed can be placed on the opposite side of the LED substrate, allowing processing to proceed while checking whether light is being irradiated evenly over the entire substrate to be processed.

[0039] Even in cases other than heat treatment, when a substrate is irradiated with light, the surface temperature changes slightly as the substrate absorbs part of the irradiated light. Therefore, it is expected that the radiation thermometer will be used not only for temperature changes in heat treatment, but also for cleaning treatment, modification (hardening) treatment, etc.

[0040] The light irradiation device is The main emission wavelength of the LED element may be within the range of 300 nm to 1050 nm.

[0041] As used herein, the term "dominant emission wavelength" refers to the wavelength at which the intensity of the emitted light is the highest.

[0042] In particular, semiconductor wafers made of silicon (Si) (hereinafter referred to as "silicon wafers") have a high absorptance and low transmittance for light in the ultraviolet to visible wavelength range, but when the wavelength is longer than 1100 nm, the absorptance drops sharply and the transmittance increases. As shown in FIG. 3, which is referred to in the explanation of the "Description of the Preferred Embodiments," when light with a wavelength of 1100 nm or more is irradiated onto a silicon wafer, approximately 50% of the light passes through the silicon wafer. For this reason, when a silicon wafer is heat-treated, it is preferable that the main emission wavelength of the light emitted from the LED element is 1050 nm or less.

[0043] Furthermore, the absorption rate of silicon wafers for light with wavelengths of less than 300 nm drops to about 10% at its lowest. Therefore, in order to ensure an absorption rate of at least 25%, it is preferable that the main emission wavelength of the light emitted from the LED element is 300 nm or more.

[0044] The light irradiation device having the above-mentioned configuration can efficiently heat-treat the silicon wafer. Effect of the Invention

[0045] According to the present invention, a light irradiation device is realized that suppresses uneven irradiation of light irradiated from an LED element to a substrate to be processed, without increasing the size of the entire device. [Brief description of the drawings]

[0046] [Figure 1] 1 is a cross-sectional view of a configuration of an embodiment of a light irradiation device when viewed in the Y direction. [Diagram 2] This is a drawing of the LED board as seen from the -Z side. [Diagram 3] 1 is a graph showing spectra of absorptance and transmittance of light of a silicon wafer. [Figure 4] This is a drawing of the cooling member as seen from the +Z side. [Diagram 5] 11 is a graph showing an example of the relative intensity of light irradiated onto the main surface of the substrate to be processed in each configuration. [Figure 6] 1 is a cross-sectional view of a configuration of an embodiment of a light irradiation device when viewed in the Y direction. [Figure 7] This is a drawing of the LED board as seen from the -Z side. [Figure 8] This is a drawing of the cooling member as seen from the +Z side. [Figure 9] FIG. 11 is a schematic cross-sectional view of a conventional light irradiation device as viewed in the Y direction. [Figure 10] FIG. 11 is a schematic cross-sectional view of a conventional light irradiation device as viewed in the Y direction. [Figure 11] FIG. 11 is a schematic cross-sectional view of a conventional light irradiation device as viewed in the Y direction. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0047] The light irradiation device of the present invention will be described below with reference to the drawings. Note that the following drawings related to the light irradiation device are all schematic illustrations, and the dimensional ratios and numbers in the drawings do not necessarily match the actual dimensional ratios and numbers.

[0048] [First embodiment] Fig. 1 is a cross-sectional view of the configuration of one embodiment of a light irradiation device 1 when viewed in the Y direction. As shown in Fig. 1, the light irradiation device 1 of the first embodiment includes a chamber 10 in which a substrate W1 to be processed is accommodated, a plurality of LED elements 11, an LED substrate 12 on which the LED elements 11 are mounted, a radiation thermometer 14, and a supply mechanism 15. The first embodiment will be described on the assumption that the substrate W1 to be processed is a silicon wafer, but the substrate W1 may be a semiconductor wafer made of a material other than silicon, a glass substrate, or the like.

[0049] In the following description, the direction in which the LED substrate 12 and the substrate W1 to be processed face each other is defined as the Z direction, the direction in which the pair of support members 13 face each other is defined as the X direction, and the direction perpendicular to the X direction and the Z direction is defined as the Y direction, as shown in Fig. 1. In addition, in the light irradiation device 1, as shown in Fig. 2 described later, the arrangement of the LED elements 11 has the same structure when viewed in the X direction and when viewed in the Y direction, so unless otherwise necessary, only the structure when viewed in the Y direction will be described.

[0050] Similarly, 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," whereas when a direction is expressed without distinguishing between positive and negative directions, it is simply written as "Z direction."

[0051] 1, the chamber 10 includes a support member 13 for supporting the substrate W1 inside the chamber 10. The support member 13 supports the substrate W1 such that the main surface W1a of the substrate W1 is disposed on the XY plane.

[0052] The support member 13 supports the substrate W1 so long as its main surface W1a is disposed on the XY plane, and may have a plurality of pin-shaped protrusions that support the substrate W1 at points. Here, the main surface W1a is a surface on which circuit elements, wiring, etc. are formed and on which light emitted from the LED elements 11 is irradiated.

[0053] The chamber 10 also has a light-transmitting window 10a on the wall surface on the +Z side for taking in the light emitted from the LED element 11. The chamber 10 may have any shape, such as a cylindrical shape or a square tube shape.

[0054] The LED elements 11 are disposed on the −Z side principal surface of the LED substrate 12, which is disposed so as to face the principal surface W1a of the substrate W1 supported by the support member 13.

[0055] 1, the light-transmitting window 10a of the chamber 10 is configured to face the main surface W1a of the substrate W1 to be processed supported by the support member 13. That is, the light emitted from the LED element 11 is irradiated onto the main surface W1a of the substrate W1 to be processed through the light-transmitting window 10a.

[0056] 2 is a drawing of the LED substrate 12 as viewed from the -Z side. As shown in FIG. 2, the LED elements 11 are arranged point-symmetrically with respect to the center of the LED substrate 12. The LED elements 11 are arranged in three concentric regions, a first region A1 on the outermost side, a second region A2 inside the first region A1 and spaced apart from the first region A1, and a third region A3 sandwiched between the first region A1 and the second region A2. Note that in FIG. 2, the boundaries of the regions (A1, A2, A3) are shown by dashed lines, but these are shown for the purpose of explanation and are not shown on the actual LED substrate 12.

[0057] As shown in FIG. 2, each region (A1, A2, A3) is arranged such that the number of LED elements 11 per unit area, i.e., the arrangement density of the LED elements 11, satisfies the relationship: first region A1>second region A2>third region A3.

[0058] In the first embodiment of the light irradiation device 1, the ratio of the width in the radial direction of each region (A1, A2, A3) to the radius of the LED substrate 12 is A1: 16%, A2: 66%, and A3: 18%. From the viewpoint of improving the uniformity of light, it is preferable that this ratio is A1: 20% or less, A2: 60% or more, and A3: 20% or less.

[0059] The number of LED elements 11 arranged in the second region A2 is set to 1, and the ratio of the number of elements in each region (A1, A2, A3) is set to A1:A2:A3 = 1.5:1.0:0.3. From the viewpoint of improving the uniformity of light, it is preferable that the number of LED elements 11 in the first region A1 is 1.2 to 2.0 times the number of LED elements 11 in the second region A2, and the number of LED elements 11 in the third region A3 is 0.1 to 0.5 times the number of LED elements 11 in the second region A2.

[0060] Furthermore, the LED elements 11 in each region (A1, A2, A3) are supplied with power from a power supply source (not shown) so that the ratio of the total power supplied to all the LED elements 11 arranged in the second region A2 is 1, and the ratio of the total power supplied to all the arranged LED elements 11 is A1:A2:A3=1.5:1.0:0.3. That is, the ratio of the total power supplied divided by the area of ​​the region is the first region A1>the second region A2>the third region A3. As a result, the luminance of each region (A1, A2, A3) is the first region A1>the second region A2>the third region A3. From the viewpoint of improving the uniformity of light, it is preferable that the total power supplied to the first region A1 is 1.2 to 2.0 times the total power supplied to the second region A2, and the total power supplied to the third region A3 is 0.1 to 0.5 times the total power supplied to the second region A2.

[0061] FIG. 3 is a graph showing the spectrum of the absorptance and transmittance of a silicon wafer with no elements or wiring formed thereon. In FIG. 3, the solid line corresponds to the absorptance, and the dashed line corresponds to the transmittance. As shown in FIG. 3, the absorptance of the silicon wafer exceeds the transmittance for light in the wavelength band of 1100 nm or less, and the transmittance exceeds the absorptance for light in the wavelength band of 1100 nm or more. Therefore, when the substrate W1 to be processed is a silicon wafer and the light irradiation device 1 is used for heat treatment, it is preferable that the main emission wavelength of the light emitted from the LED element 11 is 1050 nm or less.

[0062] Furthermore, silicon wafers have a significantly low absorptivity for light in the wavelength band less than 300 nm. Therefore, when the substrate W1 to be processed is a silicon wafer and the light irradiation device 1 is used for heat treatment, it is preferable that the main emission wavelength of the light emitted from the LED element 11 is 300 nm or more.

[0063] The light irradiation device 1 of the first embodiment is a device for heat-treating a silicon wafer and is equipped with an LED element 11 that emits light having a main emission wavelength of 395 nm for the above-mentioned reasons, but may be equipped with an LED element 11 having a main emission wavelength other than 395 nm depending on the intended use. Also, the light irradiation device 1 may be equipped with a mixture of LED elements 11 having different main emission wavelengths.

[0064] 1 and 2, the LED substrate 12 has an observation hole 12a at its center connecting the main surfaces of the LED substrate 12 in order to measure the temperature of the main surface W1a of the substrate W1 to be processed by a radiation thermometer 14 arranged on the +Z side of the LED substrate 12. The observation hole 12a in the first embodiment is formed with a diameter of 15 mm, but in view of the relationship between the arrangement area of ​​the LED elements 11, the measurement range of the radiation thermometer 14, and the diameter of the substrate W1 to be processed whose temperature is to be measured, the diameter of the observation hole 12a is preferably within a range of 5 mm to 30 mm.

[0065] The LED substrate 12 is provided, on the surface opposite to the surface on which the LED elements 11 are mounted, with a cooling member 12z in which an inlet 12p, an outlet 12q, and a flow path 12c connecting these are formed.

[0066] The supply mechanism 15 is connected to an inlet 12p and an outlet 12q formed in the cooling member 12z by a water pipe 15a, as shown in Fig. 1. As shown by the dashed arrow in Fig. 1, the supply mechanism 15 feeds cooling water C1 into the inlet 12p, and receives cooling water C2 that has flowed through a flow path 12c formed in the cooling member 12z and discharged from the outlet 12q.

[0067] In the first embodiment, a configuration is described in which cooling water is passed through the flow path 12c of the cooling member 12z as a cooling medium for cooling. However, a cooling medium other than water, for example, a fluorine-based inert liquid, etc. may also be used.

[0068] In the first embodiment, the cooling water C2 discharged from the outlet 12q is configured to be returned to the supply mechanism 15, but it may be configured to be discharged directly to the outside of the light irradiation device 1.

[0069] 4 is a drawing of the cooling member 12z as viewed from the +Z side, and an example of flow paths (12c, 12d) formed inside through which the cooling water C1 flows is shown by dashed lines, although it is not actually visible. The flow path 12c is configured to connect the inlet 12p to the outlet 12q in the order of the first area A1, the second area A2, and the third area A3, and a bypass flow path 12d for connecting the first area A1 to the second area A2 is formed in a part of the third area A3.

[0070] 1, the supply mechanism 15 is connected to the inlet 12p and the outlet 12q by the water distribution pipe 15a, but a water distribution plate having a water distribution channel may be provided instead of the water distribution pipe 15a. The water distribution plate does not require as large an arrangement space as the water distribution pipe 15a, so that the entire light irradiation device 1 can be made smaller.

[0071] The main component of the material of the LED substrate 12 on which the LED elements 11 are mounted is ceramic such as metal oxide or metal nitride, which is an insulator, and aluminum nitride or silicon nitride, which has high thermal conductivity, is particularly preferable.

[0072] As shown in FIG. 4, the flow path 12c connects the inlet 12p and the outlet 12q so that the air passes through the first area A1, the second area A2, and the third area A3 of the LED substrate 12 in this order from the inlet 12p.

[0073] Further, the flow paths 12c are formed so as to connect a specific inlet 12p and outlet 12q, and each flow path 12c is configured so as to be point symmetric with respect to the center of the LED substrate 12.

[0074] For example, when the flow passage 12c is formed so as to go around the peripheral end of the cooling member 12z in the circumferential direction, the cooling water C1 absorbs heat while flowing and the temperature gradually increases. For this reason, a temperature gradient occurs in the LED substrate 12 in the circumferential direction.

[0075] With the above configuration, the cooling water C1 is fed from the supply mechanism 15 to each inlet 12p, and the LED substrate 12 is cooled point-symmetrically, so that the temperature gradient in the circumferential direction of the LED substrate 12 is suppressed compared to the case where the flow path 12c is formed to go around the peripheral end. Therefore, the temperature unevenness of the entire LED substrate 12 is suppressed.

[0076] 1 and 2, the reduction in the intensity of the light irradiated to the peripheral end W1e of the main surface W1a of the substrate W1 to be processed is suppressed without increasing the size of the chamber 10 or the LED substrate 12. In this way, the difference between the intensity of the light irradiated to the central portion W1c and the intensity of the light irradiated to the peripheral end W1e is reduced.

[0077] In addition, the region W1d between the central portion W1c and the peripheral edge portion W1e is irradiated with low-brightness light from the third region A3, which has a low density of LED elements 11, thereby improving the uniformity of the light intensity distribution over the entire main surface W1a of the processed substrate W1 compared to the conventional method.

[0078] Furthermore, by employing the cooling configuration described with reference to FIG. 4, the temperature distribution over the entire LED substrate 12 can be made more uniform.

[0079] Therefore, the uniformity of the light irradiated onto the substrate W1 to be processed is improved without increasing the size of the light irradiation device 1.

[0080] Fig. 5 is a graph showing an example of the relative intensity of light irradiated onto the main surface W1a of the substrate W1 in each configuration. The graph shown in Fig. 5 is a graph of the relative intensity to the light intensity at the center (0 mm) of the substrate W1 when the substrate W1 has a diameter of 300 mm and is irradiated with light from each LED substrate 12 designed with different arrangements of the LED elements 11 as described below. In calculating the relative intensity, the distance between the substrate W1 and the LED substrate 12 in the Z direction was set to 60 mm, but the distance is preferably set in the range of 45 mm to 80 mm.

[0081] L1 is a calculation result for a configuration in which the LED elements 11 are arranged at approximately equal intervals over the entire LED substrate 12. L2 is a calculation result for a configuration in which the LED elements 11 are arranged at a high density only in an area that is 30 mm or more away from the center of the LED substrate 12. L3 is a calculation result for a configuration that satisfies the conditions of the first embodiment described above, although there are some differences from the configurations shown in Figures 1 and 2.

[0082] In a configuration in which the LED elements 11 are arranged at approximately equal intervals across the entire LED substrate 12, as shown by L1 in Figure 5, the intensity drops significantly on the peripheral edge W1e side (distance from the center 100 mm or more) compared to the central portion W1c side (distance from the center 100 mm or less) of the substrate W1 to be processed, and at a position 150 mm away from the center, the light intensity drops to 50% or less compared to the central portion.

[0083] In a configuration in which the LED elements 11 are densely arranged only in an area 30 mm or more away from the center of the LED substrate 12, the light intensity becomes higher in an area where the light emitted from the LED elements 11 arranged in the first area A1 overlaps with the light emitted from the LED elements 11 arranged in the second area A2 than in other areas, as shown by L2 in Fig. 5. This is believed to be due to the occurrence of an area where the light emitted from the LED elements 11 arranged on the central part W1c side overlaps with the light emitted from the LED elements 11 arranged on the peripheral end part W1e side.

[0084] According to the configuration of the first embodiment, as shown by L3 in Fig. 5, a large decrease in light intensity at the peripheral end (100 mm or more away from the center) of the substrate W1 to be processed is suppressed, and no region occurs in which the relative intensity to the light intensity at the center exceeds 1.1 at any position. This is believed to be because the light emitted from the region (first region A1) where the LED elements 11 are densely arranged on the peripheral end W1e side overlaps with the light emitted from the region (third region A3) where the LED elements 11 are less densely arranged than on the central portion W1c side, resulting in a lower light intensity in total than the region (second region A2) on the central portion W1c side.

[0085] 5, the decrease in light intensity at a distance of 150 mm from the center is improved compared to L1, which is the result of the conventional configuration, but is still below 80% of the light intensity at the center. Therefore, in order to bring the light intensity at the peripheral edge closer to the light intensity at the center, for example, a mirror may be provided that reflects the light irradiated to the outside of the substrate W1 to be processed toward the main surface W1a of the substrate W1 to be processed.

[0086] Fig. 6 is a cross-sectional view of another configuration of the first embodiment of the light irradiation device 1 when viewed in the Y direction. As shown in Fig. 6, the light irradiation device 1 may include a mirror 70 that reflects light traveling to the outside of the substrate W1 to be processed toward the main surface W1a of the substrate W1 to be processed. By providing the mirror 70, the intensity of the light irradiated to the peripheral edge W1e of the substrate W1 to be processed is increased, and the decrease in light intensity at the peripheral edge (distance from the center 100 mm or more) of the graph of L3 shown in Fig. 5 is suppressed, and the uniformity of the intensity of the light irradiated to the main surface W1a of the substrate W1 to be processed is further improved.

[0087] In the first embodiment, the mirror 70 is arranged so that the reflecting surface 70a is parallel to the Z axis as shown in FIG. 6, but the reflecting surface 70a may be arranged so as to be inclined with respect to the Z axis.

[0088] In the light irradiation device 1 of the first embodiment, for example, if the luminance of each region (A1, A2, A3) can be configured to satisfy the relationship of first region A1>second region A2>third region A3 by adjusting the power supplied to each region (A1, A2, A3), the arrangement density of each region (A1, A2, A3) does not need to be configured to satisfy the relationship of first region A1>second region A2>third region A3.

[0089] Although the LED substrate 12 in the first embodiment is configured to have three regions, the first region A1, the second region A2, and the third region A3, the LED substrate 12 may be configured to be divided into four or more regions. In addition, another region may be sandwiched between the first region A1 and the third region A3, and between the second region A2 and the third region A3.

[0090] [Second embodiment] The configuration of the second embodiment of the light irradiation device 1 of the present invention will be described, focusing on the differences from the first embodiment.

[0091] Fig. 7 is a cross-sectional view showing a schematic configuration of a second embodiment of the light irradiation device 1. As shown in Fig. 7, in the second embodiment of the light irradiation device 1, the LED substrate 12 is formed by combining a plurality of small substrates 12n. Fig. 7 shows, as an example, a form in which the LED substrate 12 is formed by nine small substrates 12n.

[0092] Due to manufacturing or characteristic issues, there are cases where LED substrates 12 of the same size as the substrate W1 cannot be manufactured from a single plate material, for example, because large substrates are not manufactured and sold.

[0093] Therefore, as shown in FIG. 7, the LED substrate 12 is configured by combining a plurality of small substrates 12n, so that even in the above case, the light irradiation device 1 can be configured to match the size of the substrate W1 to be processed.

[0094] FIG. 8 is a drawing of the cooling member 12z as viewed from the +Z side, and similarly to FIG. 4, an example of a flow path (12c, 12d) formed inside through which the cooling water C1 flows is shown by dashed lines, although it is not actually visible.

[0095] Hereinafter, the flow path 12c of the cooling water C1 in the second embodiment will be described using some of the small substrates 12n. In the second embodiment, as shown in Fig. 1, the cooling water C1 is introduced from a supply mechanism 15 into an inlet 12p provided in a cooling member 12z. Then, the cooling water C1 (not shown) flows through the flow path 12c in the first area A1 shown in Fig. 8. In the second embodiment, each small substrate 12n is provided with a cooling member 12z having the same shape when viewed from the Z direction.

[0096] The cooling water C1 that has flowed through the flow passages 12c in the first area A1 of the cooling member 12z flows through the bypass flow passages 12d and then flows through the flow passages 12c in the second area A2.

[0097] The cooling water C1 that has flowed through the flow path 12c in the second area A2 flows into a connecting port 12s that is connected to a water distribution pipe (not shown), and flows through the water distribution pipe into the connecting port 12s of the central small substrate 12n.

[0098] The cooling water C1 that has flowed into the connecting port 12s of the small substrate 12n flows through a flow path 12c formed in the central cooling member 12z, and then flows into another connecting port 12s of the cooling member 12z.

[0099] The cooling water C1 discharged from the connecting port 12s of the central cooling member 12z flows through a water distribution pipe into the connecting port 12s provided in the third area A3 of the original cooling member 12z.

[0100] The cooling water C1 that flows into the connecting port 12s provided in the third area A3 of the original cooling member 12z flows through the flow path 12c formed in the third area A3, and is finally discharged as cooling water C2 (not shown) from the outlet 12q.

[0101] In this manner, the cooling water C1 flows from the inlet 12p through the first area A1, the second area A2, and the third area A3 in this order, and is distributed from the outlet 12q. Note that the above configuration is merely an example, and the flow path 12c may have a different configuration from the above configuration.

[0102] [Another embodiment] Another embodiment will be described below.

[0103] <1> The light irradiation device 1 may be provided with an optical system such as a lens, a prism, a diffuser plate, or an integrator optical system so that the light emitted from the LED elements 11 is evenly irradiated onto the entire main surface W1b of the workpiece substrate W1.

[0104] <2> The configuration of the light irradiation device 1 described above is merely an example, and the present invention is not limited to the illustrated configuration. [Explanation of symbols]

[0105] 1 : Light irradiation device 10: Chamber 10a: Light-transmitting window 11: LED element 12: LED board 12a: Observation hole 12c : Channel 12d: Bypass flow path 12n: Small board 12p: Inlet 12q: Outlet 12s: Connection port 12z: Cooling material 13: Support member 14 : Radiation thermometer 15 : Supply mechanism 15a: Water pipe 15b: Distribution channel 15p: Water distribution plate 70: Mirror 70a: Reflective surface 100: Light irradiation device 101: Chamber 101a: Translucent window 102: LED element 103: LED board 104: Support member A1,A2,A3: Area C1,C2: Cooling water W1: Substrate to be processed W1a: Main surface W1c: Central part W1d: Area W1e: Peripheral end

Claims

1. A light irradiation device that irradiates a substrate to be processed with light, a chamber having a light-transmitting window for accommodating the substrate to be processed; a support member for supporting the substrate to be processed within the chamber; an LED substrate disposed outside the chamber so as to face the substrate supported by the support member across the light-transmitting window; a plurality of LED elements arranged on a main surface of the LED substrate so as to emit light toward a main surface of the substrate supported by the support member; a cooling member having an inlet for introducing a cooling medium for cooling the LED elements, an outlet for discharging the cooling medium to the outside of the LED substrate, and a flow path connecting the inlet and the outlet, the cooling member being provided on a surface of the LED substrate opposite to a surface on which the LED elements are mounted; a supply mechanism that supplies the cooling medium from the inlet of the LED substrate into the flow path, When the region of the LED substrate in which the LED elements are arranged is divided into a plurality of concentric regions, the plurality of regions are: An outermost first region; a second region, which is a region inside the first region and separated from the first region, and in which a value obtained by dividing a total value of the supplied power by an area in which the LED elements are mounted is smaller than that of the first region; a third region between the first region and the second region, in which a total value of the supplied power divided by an area in which the LED elements are mounted is smaller than that of the second region; A light irradiation device, characterized in that the flow path of the cooling member passes from the inlet through the first region, the second region, and the third region of the LED substrate in that order.

2. the number of the LED elements per unit area in the second region is smaller than the number of the LED elements per unit area in the first region; 2 . The light irradiation device according to claim 1 , wherein the number of the plurality of LED elements per unit area in the third region is smaller than the number of the plurality of LED elements per unit area in the second region.

3. 3. The light irradiation device according to claim 1, wherein the LED substrate is made of a material whose main component is aluminum nitride or silicon nitride.

4. 4. The light irradiation device according to claim 1, wherein the LED substrate has a hole connecting the main surfaces of the LED substrate.

5. 5. The light irradiation device according to claim 1, wherein a main emission wavelength of the LED element is within a range of 300 nm to 1050 nm.

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