Photothermal heating device

Abstract

To provide an optical heating device enabling more precise adjustment of illuminance distribution on a main surface of a processing-target substrate.SOLUTION: An optical heating device 1 is provided which heats a processing-target substrate W1 by irradiating it with light. The optical heating device 1 comprises: a support member 3 supporting the processing-target substrate; and a light source unit 10 including a plurality of LED substrates 10b having a first main surface 10p on which a group of LED elements 10a are mounted. At least one of the plurality of LED substrates is arranged in such a manner that the first main surface is inclined to a second main surface W1a of the processing-target substrate under a state in which the processing-target substrate is supported by the support member 3.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a light heating device. [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 treatments are often performed using heat treatment methods that use light irradiation, which allows for non-contact processing.

[0003] Known devices for heat-treating substrates include those equipped with lamps such as halogen lamps or solid-state light sources such as LEDs, which irradiate the substrates with light for heating. For example, Patent Document 1 listed below describes a heating device equipped with multiple LEDs. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2020-009927 Summary of the Invention [Problem to be solved by the invention]

[0005] In recent years, with technological advances such as miniaturization in semiconductor manufacturing processes, there has been a demand for heating devices that can perform more uniform heat treatment. The present inventors have therefore been conducting extensive research into heating devices that can perform heat treatment on substrates with a more uniform temperature distribution, and have found the following problems to be solved.

[0006] In a heating device equipped with a plurality of solid-state light sources such as LEDs as light sources for emitting light for heating, such as the heating device described in Patent Document 1, the plurality of solid-state light sources have conventionally been arranged on a plane parallel to the main surface of the substrate to be processed placed on a support member. The reason why such a configuration is generally adopted is thought to be that by aligning the distance between the main surface of the substrate to be processed and each solid-state light source, it is easy to predict and examine the illuminance distribution on the main surface of the substrate to be processed, and it is also easy to control the illuminance distribution on the main surface of the substrate to be processed.

[0007] However, once the multiple solid-state light sources are fixed to the main surface of the substrate on which they are mounted by soldering or the like, it is difficult to change their positions thereafter. Therefore, in a conventional heating device that is premised on mounting multiple solid-state light sources on a plane parallel to the main surface of the substrate to be processed placed on a support member, the only way to fine-tune the illuminance distribution on the main surface of the substrate to be processed is to translate the substrate to which the solid-state light sources are fixed.

[0008] However, translation of the substrate to which the solid-state light sources are fixed does not change the arrangement of the multiple solid-state light sources. Therefore, the arrangement of the solid-state light sources may not be suitable at the destination of the substrate. Furthermore, when translating the substrate in a direction perpendicular to the main surface of the substrate, if the solid-state light sources and the substrate are brought too close together, the light emitted from the solid-state light sources will be irradiated onto the substrate before it has time to sufficiently spread, resulting in uneven illuminance.

[0009] Furthermore, if the solid-state light source is placed too far away from the substrate to be processed, the illuminance may be insufficient and the substrate may not be able to be irradiated with sufficient illuminance. In other words, with conventional heating devices, it has been difficult to fine-tune the illuminance distribution of the light irradiated onto the substrate to be processed according to each substrate.

[0010] In view of the above-mentioned problems, an object of the present invention is to provide a light heating device that can more precisely adjust the illuminance distribution on the main surface of a substrate to be processed. [Means for solving the problem]

[0011] The light heating device of the present invention is An optical heating device that heats a substrate to be processed by irradiating it with light, a support member for supporting the substrate to be processed; a light source unit including a plurality of LED substrates each having a group of LED elements mounted on a first main surface; At least one of the plurality of LED substrates is characterized in that, when the substrate to be processed is supported by the support member, the first main surface and the second main surface of the substrate to be processed are inclined.

[0012] In this specification, the term "inclined" refers to a state in which the angle formed between the first main surface and the second main surface is greater than 0° and less than 90°.

[0013] The angle between the first main surface of the LED substrate and the second main surface of the substrate to be processed supported by the support member can be continuously adjusted by adjusting the position of the LED substrate. Furthermore, when tilting the first main surface of the LED substrate with respect to the second main surface of the substrate to be processed, the rotation axis when rotating the LED substrate and the direction in which the LED substrate is tilted are arbitrary.

[0014] With the above configuration, the optical heating device can continuously adjust the illuminance distribution on the main surface of the substrate to be processed by adjusting the tilt direction of the LED substrate in addition to adjusting the arrangement of the LED elements on the first main surface of the LED substrate. In other words, the optical heating device with the above configuration can adjust the illuminance distribution on the second main surface of the substrate to be processed more precisely than conventional configurations.

[0015] In the above-mentioned light heating device, The plurality of LED substrates may include LED substrates arranged such that the first main surfaces are inclined relative to the second main surface of the substrate to be processed supported by the support member, and such that at least some of the first main surfaces are non-parallel to each other.

[0016] When heated, the temperature of the substrate to be processed, as viewed from the normal direction to the substrate's main surface (second main surface), tends to decrease as the substrate moves away from the center (i.e., closer to the peripheral edge) compared to the region closer to the center (central portion). Furthermore, as described above, when the substrate to be processed is a semiconductor wafer, a process gas is introduced during the heating process during a film formation process. Furthermore, cleaning processes may be performed on the semiconductor wafer between multiple processes. When a specific gas (e.g., a process gas) or solution (e.g., a cleaning solution) is introduced into the substrate to be processed, the temperature of a specific region tends to decrease, potentially resulting in an uneven temperature distribution. Therefore, in order to heat the substrate to be processed with a uniform temperature distribution, it is preferable to individually adjust the angle between the first main surface of each of the LED substrates and the second main surface of the substrate to be processed according to the position on the substrate to be irradiated with light.

[0017] According to the above configuration, it is possible to individually adjust the inclination angle of the first main surface of each of the plurality of LED substrates relative to the second main surface of the substrate to be processed. In other words, the inclination angle of each LED substrate is optimized depending on the arrangement position of each LED substrate and the desired light irradiation pattern on the second main surface of the substrate to be processed. As a result, the illuminance distribution on the second main surface of the substrate to be processed can be more precisely adjusted.

[0018] In the above-mentioned light heating device, Each of the plurality of LED substrates may be arranged such that, when the substrate to be processed is supported by the support member, the angle between the first main surface and the second main surface of the substrate to be processed is within a range of 20° or more and 60° or less.

[0019] Furthermore, in the above-mentioned light heating device, Each of the plurality of LED substrates may be arranged so as to satisfy the following formulas (1) to (3), when the substrate to be processed is supported by the support member, the distance between the center of the first main surface of the LED substrate and the substrate to be processed is Wd, the distance from the center of the substrate to be processed to the center of the first main surface of the LED substrate when viewed from a direction perpendicular to the second main surface of the substrate to be processed is Rd, and the angle between the first main surface of the substrate to be processed and the second main surface of the substrate to be processed is θ. 60mm≦Wd≦200mm (1) 0.75≦Rd / Wd≦2.5 (2) arctan(Rd / (2·Wd))≦θ≦arctan(Rd / Wd) (3)

[0020] This is because the light distribution characteristic of light emitted from an LED element follows cos α in the range of -90°≦α≦90°, where α is the emission angle of the light. This optical characteristic is also called "Lambertian light distribution." According to this optical characteristic, if the integral value of the light intensity in the range of -90°≦α≦90° is 100%, the integral value of the light intensity in the range of -20°≦α≦20° is approximately 40% of the total, and the integral value of the light intensity (hereinafter sometimes referred to as "relative intensity ratio") in the range of -60°≦α≦60° is approximately 90% of the total (see Figure 5).

[0021] The relative intensity ratio corresponds to the percentage change in the integrated value of the light intensity in the area irradiated with light emitted from the LED element when the LED element is not tilted, when the LED element is tilted by an angle equivalent to the emission angle α. Details will be explained in the section "Mode for Carrying Out the Invention" with reference to Figure 5.

[0022] According to the above, when the light-emitting surface of the LED element is tilted by 20° relative to the second main surface of the substrate, the integrated light intensity in the light distribution changes by approximately 40%. Furthermore, when the light-emitting surface of the LED element is tilted by 60° or more relative to the second main surface of the substrate, the integrated light intensity in the light distribution changes by approximately 90% or more. In other words, from the viewpoints of efficiently changing the illuminance distribution on the second main surface of the substrate and minimizing light waste, it is preferable that the tilt angle between the first main surface of the LED substrate and the second main surface of the substrate be in the range of 20° to 60°.

[0023] Furthermore, it is preferable to ensure an appropriate separation distance Wd (also called "work distance") between the LED substrate and the substrate to be processed so that they do not come into contact. The separation distance Wd is determined taking into consideration that, in order to achieve a more uniform illuminance distribution, the light emitted from the LED elements is irradiated onto the substrate to be processed in a state where it is somewhat spread out.

[0024] Furthermore, the inventors have been thoroughly studying the configuration of tilting the LED substrate and have discovered that the temperature distribution in the substrate to be processed during heating directly contributes to the ratio of the distance Rd to the separation distance Wd (also called the "aspect ratio"), which is expressed in the above equations (2) and (3).

[0025] Details will be explained in the section "Mode for Carrying Out the Invention" below, but by configuring the optical heating device based on the above conditions, the average value (T ave ) is suppressed to 10% or less. Designing to satisfy the above formulas (1) to (3) to obtain such a temperature distribution inevitably leads to optimizing the illuminance distribution on the second main surface, which is determined so as to heat the entire substrate to be processed uniformly.

[0026] The light heating device is A frame on which the plurality of LED substrates are placed may be provided.

[0027] Furthermore, in the above-mentioned light heating device, The frame may be provided with an angle adjustment mechanism for changing the position of the LED substrate in order to adjust the angle between the first main surface and the second main surface of the substrate to be processed supported by the support member.

[0028] With the above configuration, the LED substrate can be configured so that, simply by placing it on the frame and fixing it, the angle between the first main surface of the LED substrate and the second main surface of the substrate to be treated becomes a predetermined angle that is determined in advance depending on the substrate to be treated.

[0029] Furthermore, in the case of a frame equipped with an angle adjustment mechanism, the tilt angle of the LED substrate can be finely adjusted as needed depending on the type, size, shape, etc. of various substrates to be processed. In other words, an optical heating device with this configuration can more precisely adjust the illuminance distribution on the substrate to be processed, enabling more uniform heating processing. [Effects of the Invention]

[0030] According to the present invention, an optical heating device is realized that can more precisely adjust the illuminance distribution on the main surface of the substrate to be processed. [Brief explanation of the drawings]

[0031] [Figure 1] FIG. 2 is a schematic cross-sectional view of an embodiment of a light heating device when viewed in the Y direction. [Figure 2] 2 is a view of the chamber of FIG. 1 as seen from the +Z side. [Figure 3] This is a drawing of the frame in Figure 1 as seen from the -Z side. [Figure 4] 1 is a graph showing the relationship between the wavelength of light and the absorptance when the temperature of silicon (Si) is 543K. [Figure 5] 1 is a graph showing the relative intensity distribution of light emitted from an LED element and the relative intensity ratio in the distribution. [Figure 6A] 3 is a schematic diagram for explaining the configuration of a light source unit and the positional relationship between the light source unit and a substrate to be processed. [Figure 6B] 6B is a diagram of the light source unit and the substrate to be processed in FIG. 6A as viewed from the +Z side. [Figure 7A] 10 is a graph showing correlation characteristics between angle and temperature distribution for each aspect ratio. [Figure 7B] 7B is a graph plotting the upper and lower limit values ​​of the angle θ when ΔT / Tave is below 0.1 in the graph of FIG. 7A. [Figure 8] FIG. 2 is a schematic cross-sectional view of an embodiment of a light heating device when viewed in the Y direction. [Figure 9] FIG. 10 is a schematic cross-sectional view of another embodiment of the light heating device when viewed in the Y direction. DETAILED DESCRIPTION OF THE INVENTION

[0032] The light heating device and heat treatment method of the present invention will be described below with reference to the drawings. Note that the following drawings relating to the light heating device are all schematic illustrations, and the dimensional ratios and numbers in the drawings do not necessarily correspond to the actual dimensional ratios and numbers.

[0033] Fig. 1 is a schematic cross-sectional view of a first embodiment of a light heating device 1 as viewed in the Y direction. As shown in Fig. 1, the light heating device 1 includes a chamber 2 that accommodates a substrate W1 to be processed, and a plurality of light source units 10 that irradiate the substrate W1 to be processed with light for heating the substrate W1 accommodated in the chamber 2. The plurality of light source units 10 are supported by a frame 11.

[0034] As shown in Fig. 1, the light source unit 10 includes a plurality of LED elements 10a that emit light for heating, and an LED substrate 10b on which the plurality of LED elements 10a are mounted. Fig. 1 schematically illustrates only the chief ray L1 of the light emitted from the LED elements 10a.

[0035] In the light source unit 10 of this embodiment, LED elements 10a that emit infrared light with a peak wavelength of 850 nm are arranged on a first main surface 10p of an LED substrate 10b.

[0036] Fig. 2 is a diagram of the chamber 2 in Fig. 1 as seen from the +Z side. Fig. 3 is a diagram of the frame 11 in Fig. 1 as seen from the -Z side. Note that in Fig. 2, the translucent window 2a, which will be described later, is not hatched so that the structure inside the chamber 2 can be seen.

[0037] In the following description, as shown in FIG. 2, a plane parallel to the main surface (hereinafter referred to as the "second main surface W1a") of the substrate W1 to be processed and to be subjected to heat treatment housed in the chamber 2 is defined as the XY plane, and as shown in FIG. 1, a direction perpendicular to the XY plane is defined as the Z direction.

[0038] Also, when expressing a direction, if a distinction is made between positive and negative directions, the direction is written with a positive or negative sign, such as "+Z direction" and "-Z direction," and when a direction is expressed without distinguishing between positive and negative directions, it is simply written as "Z direction."

[0039] Furthermore, in the explanation of the first embodiment, it is assumed that the substrate W1 to be processed is a silicon wafer, but it is also envisioned that the optical heating device 1 of the present invention can be used to heat a substrate W1 to be processed other than a silicon wafer (for example, a glass substrate, etc.).

[0040] 1, the chamber 2 includes a support member 3 on which the substrate W1 to be processed is placed, and a light-transmitting window 2a for guiding light emitted from the light source unit 10 into the chamber 2. Note that in cases where the light source unit 10 is disposed inside the chamber 2 or where the inside of the chamber 2 does not need to be sealed, the chamber 2 does not need to include the light-transmitting window 2a.

[0041] 1 and 2, the support member 3 includes a base 3a and a plurality of protrusions 3b provided on the base 3a. The substrate W1 to be processed is placed and supported on the tips of the plurality of protrusions 3b. Note that the support member 3 may be configured to support the peripheral edge of the substrate W1 to be processed, or may be configured to support the substrate W1 to be processed by a non-contact suction method, as long as the support member 3 is a member that can fix or stationary the substrate W1 to a predetermined position.

[0042] 1, the support member 3 of this embodiment is provided with a rotation mechanism using a plurality of rollers 3c. When heat treatment is performed, these rollers 3c can rotate the substrate W1 to be processed on the XY plane around an axis z1 (see FIG. 2) that passes through the center of the support member 3 in the Z direction. However, if the light source unit 10 is configured to irradiate the second main surface W1a of the substrate W1 to be processed with light uniformly in the circumferential direction, the support member 3 does not need to be configured to rotate the substrate W1 to be processed. In other words, it is optional whether the support member 3 is provided with the rollers 3c.

[0043] Fig. 4 is a graph showing the relationship between light wavelength and absorptance when the temperature of silicon (Si) is 543 K. The peak wavelength of the light emitted by LED element 10a can be set arbitrarily, but as shown in Fig. 4, in order to ensure an absorptance of at least 25%, i.e., a reflectance of at least 75%, the peak wavelength is preferably 300 nm to 1000 nm, and more preferably 350 nm to 950 nm.

[0044] Furthermore, as shown in Figure 4, silicon (Si) has a small change in absorptance with respect to wavelength fluctuations for light with a wavelength in the range of 800 nm to 900 nm. Therefore, from the viewpoint of suppressing uneven heating, it is more preferable that the light emitted by the LED elements 10a mounted in the light source unit 10 has a peak wavelength of 800 nm to 900 nm, and particularly preferably 820 nm to 880 nm.

[0045] 1, the frame 11 in this embodiment is provided with an adjustment screw 11a as an angle adjustment mechanism for adjusting the tilt angle θ of the light source unit 10 so as to change the emission direction of light emitted from the LED elements 10a. Also, as shown in FIGS. 1 and 3, the frame 11 is provided with a support wall 11b for preventing the position of the light source unit 10 from shifting when the tilt of the light source unit 10 is adjusted.

[0046] 1, the frame 11 is adjusted by an adjustment screw 11a so that the first main surface 10p of the LED substrate 10b included in the light source unit 10 is tilted by an angle θ with respect to the XY plane. Note that, as the angle adjustment mechanism, for example, a mechanism such as a piezoelectric actuator or a micrometer head with an encoder may be used.

[0047] The light source unit 10 in this embodiment is configured so that the angle θ is 45° when mounted on the frame 11. However, the angle θ may be an angle other than 45°, and the multiple LED substrates 10b may be arranged so that the angles θ formed between the first main surfaces 10p and the second main surface W1a of the substrate to be processed W1 are different, that is, so that the first main surfaces 10p of the multiple LED substrates 10b are not parallel to each other.

[0048] Here, we will explain the setting of the angle θ. Figure 5 shows graph G1, which displays the relative relationship of the light intensity for each output angle of light emitted from an LED element, superimposed on graph G2, which displays the relative value (relative intensity ratio) of the integrated value of the light intensity from 0° to the output angle α in graph G1 to the integrated value of the light intensity over the range 0°≦α≦90° (for a negative output angle α, -90°≦α≦0°). In the graph shown in Figure 5, the horizontal axis represents the output angle α, the left vertical axis represents the relative value of the light intensity associated with graph G1, and the right vertical axis represents the relative intensity ratio associated with graph G2.

[0049] An LED element is composed of a stack of semiconductor layers, and generally, the top or bottom surface constitutes the light extraction surface. That is, as shown in Figure 5, it is known that when the intensity of light emitted at an emission angle of 0° is normalized as 1, the intensity of light emitted at an emission angle α has a light distribution expressed as cos α. Regarding this light distribution, the integral value obtained by integrating the light intensity from 0° to the emission angle α is proportional to the absolute value of sin α, because it is the sum of the light intensities and can be calculated by integrating cos α with respect to α.

[0050] Graph G2 in Fig. 5 shows, for each output angle α, the percentage of the integral of the light intensity of light emitted from the LED within the range of output angles 0° to α, relative to the integral of the light intensity over the range of output angles 0°≦α≦90° (-90°≦α≦0° for negative output angles α). This characteristic corresponds to the percentage change in the integral of the light intensity in the area irradiated by light emitted from an LED element that is not tilted, when the LED element 10a is tilted by an angle equivalent to the output angle α.

[0051] 5, when the light-emitting surface of the LED element 10a is tilted by 20° relative to the second main surface W1a of the substrate W1, the integrated value of the light intensity in the area irradiated with light emitted from the LED element in an untilted state changes by approximately 40%. When the light-emitting surface of the LED element 10a is tilted by 60° or more relative to the second main surface W1a of the substrate W1, the integrated value of the light intensity in the area changes by approximately 90% or more.

[0052] In other words, it is preferable that the angle θ between the first main surface 10p of the LED substrate 10b and the second main surface W1a of the substrate to be processed W1 be in the range of 20° or more and 60° or less, from the viewpoint of efficiently changing the illuminance distribution on the second main surface W1a of the substrate to be processed W1 and from the viewpoint of suppressing wasted light.

[0053] Below, we will explain a more preferable positional relationship between the light source unit 10 and the substrate W1 to be processed, in order to make the temperature distribution in the substrate W1 more uniform. Note that when heat-treating a substrate W1 that does not require extremely high temperature uniformity during heat treatment, such as a semiconductor wafer, the optical heating device 1 does not have to satisfy the arrangement conditions described below.

[0054] First, the separation distance between the light source unit 10 and the substrate W1 to be processed will be described. Fig. 6A is a schematic diagram for explaining the configuration of the light source unit 10 and the positional relationship between the light source unit 10 and the substrate W1 to be processed, and Fig. 6B is a diagram of the light source unit 10 and the substrate W1 to be processed in Fig. 6A as viewed from the +Z side.

[0055] 6A and 6B, for convenience of explanation, the angle θ between the first main surface 10p and the second main surface W1a and the size ratio between the light source unit 10 and the substrate W1 to be processed are shown differently from those in Fig. 1, and only the periphery of the light source unit 10 is shown. Also, for convenience of explanation, the chamber 2 and the LED elements 10a provided in the light source unit 10 are not shown in Fig. 6A.

[0056] As shown in Figure 6A, the light source unit 10 has a distance Wd between the center 10c of the first main surface 10p of the LED substrate 10b and the substrate to be processed W1, and a distance Rd between the axis z2 passing through the center W1c of the substrate to be processed W1 in the Z direction and the center 10c of the light source unit 10.

[0057] The separation distance Wd is preferably set to satisfy the above formula (1) from the viewpoint of preventing contact between the light source unit 10 and the substrate W1 to be processed when the light source unit 10 is tilted, and from the viewpoint of sufficiently irradiating the substrate W1 to be processed with the light necessary for heating. 60mm≦Wd≦200mm (1)

[0058] In this embodiment, the separation distance Wd is set to 100 mm, and the distance Rd is set to 150 mm.

[0059] Next, the correlation characteristics between the angle θ and the temperature distribution for each aspect ratio (=Rd / Wd), which is the ratio of the separation distance Wd to the distance Rd, will be described. Figure 7A is a graph showing the correlation characteristics between the angle θ and the temperature distribution for each aspect ratio, and Figure 7B is a graph showing the correlation characteristics between the angle θ and the temperature distribution for each separation distance Wd, and Figure 7C is a graph showing the correlation characteristics between the angle θ and the temperature distribution for each aspect ratio, and Figure 7D is a graph showing the correlation characteristics between the angle θ and the temperature distribution for each aspect ratio, and Figure 7E is a graph showing the correlation characteristics between the angle θ and the temperature distribution for each aspect ratio, and Figure 7F is a graph showing the correlation characteristics between the angle θ and the temperature distribution for each aspect ratio, and Figure 7G is a graph showing the correlation characteristics between the angle θ and the temperature distribution for each aspect ratio, and Figure 7H is a graph showing the correlation characteristics between the angle θ and the temperature distribution for each aspect ratio, ave1 is a graph plotting the upper and lower limits of the angle θ when is less than 0.1.

[0060] In the graph shown in FIG. 7A, the vertical axis represents the difference ΔT between the maximum and minimum values ​​of the temperature distribution of the substrate W1 to be processed, and the average value T of the entire temperature distribution. ave 7A is a graph obtained by simulation, and each aspect ratio was adjusted by changing the separation distance Wd in the light heating device 1 having the configuration shown in FIG.

[0061] In the graph shown in Figure 7B, the vertical axis represents the angle θ and the horizontal axis represents the separation distance Wd. The dotted dots represent the relationship between ΔT / T ave is less than 0.1, and the plot of the square points indicates the lower limit of the angle θ when ΔT / T ave 7B shows the upper limit of the angle θ when Rd is below 0.1. For ease of explanation, the vertical axis in FIG. 7B is displayed so that the value of the angle θ decreases as it goes up. Also, in FIG. 7B, the horizontal axis is displayed as the separation distance Wd, but as mentioned above, since Rd is fixed at 150 mm, it directly corresponds to the aspect ratio.

[0062] Specifically, the aspect ratios correspond to 0.75 (Wd = 200 mm), 1.00 (Wd = 150 mm), 1.50 (Wd = 100 mm), 2.00 (Wd = 75 mm), 2.50 (Wd = 60 mm), and 3.00 (Wd = 50 mm), respectively.

[0063] As shown in Figure 7A, ΔT / T ave As the aspect ratio increases, the angle θ at which the minimum value is reached gradually increases. When the separation distance Wd is large, the light emitted from the LED element is irradiated onto the substrate W1 to be processed in a more spread state, so the minimum value appears in a range where the angle θ is relatively small. When the separation distance Wd is small, the larger the angle θ, the wider the range where the light is irradiated onto the second main surface W1a of the substrate W1 to be processed, which tends to result in more uniform heating, so the minimum value appears in a range where the angle θ is relatively large.

[0064] Furthermore, when the distance Rd is large (including when the distance Rd is larger than the radius of the substrate W1 to be processed), if the angle θ is too small, light tends to concentrate on the peripheral edge of the substrate W1 to be processed, and most of the heat generated at the peripheral edge is directly released from the peripheral edge. In other words, the minimum value appears in a range where the angle θ is relatively large so that light can also be irradiated to the central side of the substrate W1 to be processed. When the distance Rd is small, setting the angle θ small makes it easier for light to be irradiated to the central side of the substrate W1 to be processed, and the heat flowing from the central side to the peripheral edge tends to result in relatively uniform heating. For this reason, the minimum value appears in a range where the angle θ is relatively small.

[0065] In recent years, when a more precise temperature distribution uniformity is required, such as in the fine processing of semiconductor manufacturing, ΔT / T ave There is a demand for a light heating device that can perform heat treatment so that ΔT / T ave is preferably 0.1 or less.

[0066] First, in the range of the angle θ mentioned above, 20° to 60°, ΔT / T ave The area where is less than 0.1 is included when the aspect ratio is within the range shown in the above formula (2). Just to be sure, the above formula (2) is shown again. 0.75≦Rd / Wd≦2.5 (2)

[0067] In addition, assuming that the aspect ratio satisfies the above formula (2), ΔT / T ave The condition under which is less than 0.1 is determined as follows from FIGS. 7A and 7B.

[0068] In FIG. 7A, assuming that the aspect ratio satisfies the above formula (2), ΔT / T aveAs shown in Figure 7B, the condition for angle θ to be less than 0.1 can be derived from the approximate curve (dashed line) of the lower limit value and the approximate curve (dashed line) of the upper limit value for each separation distance Wd (aspect ratio), that is, θ1≦θ≦θ2. θ1 and θ2 can be expressed using distance Rd and separation distance Wd, respectively, based on the positional relationship shown in Figure 6A, and this condition is expressed as equation (3) above. Just to be sure, equation (3) above is presented again. arctan(Rd / (2·Wd))≦θ≦arctan(Rd / Wd) (3)

[0069] Therefore, by being configured to satisfy the above formulas (1) to (3), the light heating device 1 performs heat treatment so as to reduce the temperature difference over the entire substrate W1 to be treated.

[0070] 6A, the angle formed by an imaginary line s1 drawn from the center W1c of the second main surface W1a of the substrate to be processed W1 toward the center 10c of the LED substrate 10b and an axis z2 passing through the center of the second main surface W1a of the substrate to be processed W1 in the Z direction corresponds to θ1. As shown in Fig. 6B, when viewed from the Z direction, a point W1h is defined as a point on the substrate to be processed W1 that overlaps with the midpoint of a line drawn from the center W1c of the substrate to be processed W1 toward the center 10c of the LED substrate 10b, and as shown in Fig. 6A, the angle formed by an imaginary line s2 drawn from point W1h toward the center 10c of the LED substrate 10b and the axis z2 corresponds to θ2.

[0071] In other words, in this embodiment, when the condition of the above equation (3) is illustrated schematically to correspond to the configuration of this embodiment, as shown in Figure 6A, it corresponds to the condition that a line passing through the center 10c of the LED substrate 10b in a direction perpendicular to the first main surface 10p passes between the center W1c and the midpoint W1h of the substrate to be processed W1.

[0072] As described above, with the above configuration, the optical heating device 1 can continuously adjust the illuminance distribution on the second main surface W1a of the substrate to be processed W1 by adjusting the arrangement pattern of the LED elements 10a group, as well as the angle between the first main surface 10p of the LED substrate 10b and the second main surface W1a of the substrate to be processed W1, the tilt direction of the LED substrate 10b, etc. In other words, the optical heating device 1 can adjust the illuminance distribution on the second main surface W1a of the substrate to be processed W1 more finely than with conventional configurations.

[0073] Fig. 8 is a schematic cross-sectional view of an embodiment different from the light heating device 1 shown in Fig. 1, as viewed in the Y direction. The frame 11 in this embodiment may be configured to fix the light source unit 10 at a predetermined angle θ without including the adjustment screw 11a and the support wall 11b, as shown in Fig. 8.

[0074] In the above embodiment, the light heating device 1 includes a frame 11 for fixing the plurality of light source units 10, and the angle θ at which the plurality of light source units 10 are fixed is set by the shape of this frame 11. In another aspect, the light heating device 1 may not include the frame 11, and may be configured such that each of the plurality of light source units 10 is fixed separately at a predetermined position so as to form a predetermined angle θ.

[0075] Furthermore, as shown in FIG. 1, in the frame 11 of this embodiment, the first main surface 10p of the LED substrate 10b is rotated by an angle θ around the Y axis as the axis of rotation from a state in which it coincides with the XY plane, thereby tilting the light source unit 10. However, the axis of rotation can be chosen arbitrarily as long as it is an axis parallel to the XY plane.

[0076] Furthermore, as shown in Figure 8, the light heating device 1 may include a light source unit 10 in which the first main surface 10p of the LED substrate 10b is parallel to the XY plane, i.e., the first main surface 10p is parallel to the second main surface W1a of the substrate W1 to be treated.

[0077] [Another embodiment] Another embodiment will be described below.

[0078] <1> Fig. 9 is a schematic cross-sectional view of another embodiment of the light heating device 1 when viewed in the Y direction. As shown in Fig. 9, the other embodiment of the light heating device 1 includes a control unit 90 and a drive mechanism 11c that is an angle adjustment mechanism that changes the position of the LED substrate 10b based on a drive signal d2 output from the control unit 90. The control unit 90 in this embodiment includes an input unit 90a, a memory unit 90b, a determination unit 90c, and an output unit 90d.

[0079] The input unit 90a accepts input of data d1 containing information about the substrate W1. The memory unit 90b stores a table of values ​​of the separation distance Wd and angle θ that satisfy the above formulas (1) to (3) corresponding to the information about the substrate W1 contained in the data d1. The determination unit 90c references the information about the substrate W1 contained in the data d1 input to the input unit 90a and determines the values ​​of the angle θ and the separation distance Wd based on the table stored in the memory unit 90b. The output unit 90d outputs a drive signal d2 to the drive mechanism 11c so that the angle θ between the first main surface 10p of the LED substrate 10b and the second main surface W1a of the substrate W1 and the separation distance Wd between the LED substrate 10b and the substrate W1 become the values ​​determined by the determination unit 90c.

[0080] With the above configuration, the optical heating device 1 determines the angle θ and the separation distance Wd that satisfy the above equations (1) to (3) based on the information on the substrate W1 to be processed input to the control unit 90, and automatically adjusts the position of the LED substrate 10b to the optimal position.

[0081] <2> The light heating device 1 may be provided with an angle sensor for measuring the angle θ formed between the first main surface 10p and the second main surface W1a. By providing such an angle sensor, the light heating device 1 can adjust the arrangement position of the light source unit 10 while checking whether the arrangement position of the light source unit 10 satisfies the condition of the above formula (3).

[0082] Furthermore, the optical heating device 1 of this embodiment can be configured to detect a state in which the condition of the above equation (3) is no longer satisfied, for example, when the position of the light source unit 10 is displaced due to a large impact, and issue an alert.

[0083] As the angle sensor of the light heating device 1 of this embodiment, for example, a rotary potentiometer or a rotary encoder can be used.

[0084] <3> The configuration of the light heating device 1 described above is merely an example, and the present invention is not limited to the illustrated configurations. [Explanation of symbols]

[0085] 1 : Optical heating device 2: Chamber 2a: Translucent window 3: Support member 3a: Pedestal 3b: Protrusion 3c: Laura 10: Light source unit 10a: LED element 10b: LED board 10c: center 10p: First principal surface 11: Frame 11a: Adjustment screw 11b: Support wall 11c: Drive mechanism 90: Control section 90a: Input section 90b: Storage section 90c: Judgment section 90d: Output section L1: Chief ray W1: Substrate to be processed W1a: Second principal surface

Claims

1. An optical heating device that heats a substrate to be processed by irradiating it with light, a support member for supporting the substrate to be processed; a light source unit including a plurality of LED substrates each having a group of LED elements mounted on a first main surface; at least one of the plurality of LED substrates is arranged such that the first main surface and the second main surface of the substrate to be processed are inclined with respect to each other in a state in which the substrate to be processed is supported by the support member; Each of the plurality of LED substrates is arranged so that, when the substrate to be processed is supported by the support member, the angle between the first main surface and the second main surface of the substrate to be processed is within a range of 20° to 60°, and the distance between the center of the first main surface of the LED substrate and the substrate to be processed is Wd, the distance from the center of the substrate to be processed to the center of the first main surface of the LED substrate when viewed from a direction perpendicular to the second main surface of the substrate to be processed is Rd, and the angle between the first main surface of the substrate to be processed and the second main surface of the substrate to be processed is θ. An optical heating device characterized in that the LED substrates are arranged so as to satisfy the following formulas (1) to (3): 60 mm ≦ Wd ≦ 200 mm (1) 0.75≦Rd / Wd≦2.5 (2) arctan(Rd / (2・Wd))≦θ≦arctan(Rd / Wd) (3)

2. The optical heating device described in claim 1, characterized in that the multiple LED substrates are arranged so that the first main surface is inclined relative to the second main surface of the substrate to be processed supported by the support member, and include LED substrates arranged so that the first main surfaces are non-parallel to each other in at least some parts.

3. An optical heating device that heats a substrate to be processed by irradiating it with light, a support member for supporting the substrate to be processed; a light source unit including a plurality of LED substrates each having a group of LED elements mounted on a first main surface; a frame on which the plurality of LED substrates are mounted, The light heating device is characterized in that the frame is equipped with an angle adjustment mechanism that changes the position of the LED substrate in order to adjust the angle between the first main surface and the second main surface of the substrate to be processed supported by the support member.

4. The optical heating device described in Claim 3, characterized in that the multiple LED substrates are arranged so that the first main surface is inclined relative to the second main surface of the substrate to be treated supported by the support member, and include LED substrates arranged so that the first main surfaces are non-parallel to each other in at least some parts.

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