Optical heating method, and optical heating device for n-type sic semiconductor

Abstract

Provided is an optical heating method by which it is possible to efficiently heat a to-be-processed body including an n-type SiC semiconductor.　The present invention includes a step (a) in which a to-be-processed body containing an n-type SiC semiconductor is irradiated with heating light, which has a peak wavelength in the range of 415nm to 500nm and is emitted from a light source unit, through a window member to heat the to-be-processed body.

Description

Optical heating method and optical heating device for n-type SiC semiconductor

[0001] The present invention relates to an optical heating method, and more particularly to an optical heating method for an object to be treated including an n-type SiC semiconductor.The present invention also relates to an optical heating device for an n-type SiC semiconductor.

[0002] In semiconductor manufacturing processes, various heat treatments such as film formation, oxidation / diffusion, modification, and annealing are performed on objects to be treated, including semiconductor wafers. Light is often used in these heat treatments. Heating an object to be treated using light in this way is called "light heating." Furthermore, the light used for heating is called "heating light."

[0003] A known example of a semiconductor heating device that uses optical heating is the technology disclosed in Patent Document 1. The device in Patent Document 1 uses an LED lamp as a light source that emits heating light with a wavelength of 810 nm to 980 nm.

[0004] Japanese Patent Application Laid-Open No. 2020-009927

[0005] "Polymer Materials Technology for Photoresist Materials" Akimasa Seiyano, Journal of the Society of Rubber Science and Technology of Japan, Vol. 85, No. 2 (2012), pp. 33-39

[0006] In recent years, the development of power semiconductor devices capable of handling higher voltages and currents than conventional devices has been progressing. While conventional devices generally use Si, the use of SiC has been considered for recent devices in order to realize compact devices with high breakdown voltage characteristics. SiC is classified into n-type SiC, which has a relatively low resistivity, and semi-insulating SiC (sometimes referred to as "semi-insulating SiC"), which has a relatively high resistivity. N-type SiC, in particular, has attracted attention due to its wide range of applications.

[0007] Generally known n-type SiC is SiC doped with nitrogen (N) as a dopant, and generally known semi-insulating SiC is SiC doped with vanadium (V) as a dopant or SiC in which lattice defects are intentionally formed.

[0008] SiC has a larger band gap than conventional Si, a high breakdown field strength, and other properties, and is expected to reduce environmental impact through low loss, miniaturization, and weight reduction. However, SiC transmits most of the light emitted from LED lamps such as those described in Patent Document 1, making it difficult to heat efficiently. Patent Document 1 does not specifically consider the case where a SiC wafer is used as the heating object. For this reason, Patent Document 1 does not mention at all that there is a wavelength range of light that is suitable for heat-treating SiC wafers.

[0009] In view of the above-mentioned problems, the present invention aims to provide an optical heating method capable of efficiently heating a workpiece containing an n-type SiC semiconductor, and also aims to provide an optical heating device suitable for heating a workpiece containing an n-type SiC semiconductor.

[0010] The light heating method according to the present invention is characterized by comprising a step (a) of irradiating a workpiece including an n-type SiC semiconductor with heating light emitted from a light source unit and having a peak wavelength in the range of 415 nm to 500 nm through a window member to heat the workpiece.

[0011] In the light heating method, the heating light preferably has a peak wavelength in the range of 420 nm to 490 nm.

[0012] The present inventors have made the following discovery while conducting extensive research into methods for heating SiC-containing workpieces. SiC comes in a variety of crystal structures, including 4H-SiC (band gap 3.3 eV), 6H-SiC (band gap 3 eV), and 3C-SiC (band gap 2.2 eV). In the case of 6H-SiC, which has a band gap of 3 eV, the transmittance of light gradually increases in the wavelength range longer than about 420 nm, and almost all light in the wavelength range longer than 500 nm is transmitted.

[0013] As mentioned above, SiC is classified into n-type, semi-insulating, and other types depending on the dopant used. The absorption rate of SiC can change simply by doping it with a dopant. For this reason, there is no wavelength range that is recognized as being suitable for photothermal treatment of SiC.

[0014] In light of the above background, the present inventors investigated the possibility of deriving the absorptance for each wavelength of n-type SiC, which is particularly expected to be put to practical use, and finding a wavelength band of light suitable for optically heating n-type SiC. At the time of filing this application, it was difficult to directly measure the absorption spectrum of n-type SiC, so the present inventors adopted a method of measuring the reflectance R and transmittance T of n-type SiC and deriving the absorptance A (= 1 - R - T), thereby deriving the absorptance for each wavelength of n-type SiC.

[0015] Specifically, the reflectance R is measured and derived using an n-type SiC wafer, a light source whose intensity spectrum of emitted light is known, and a spectrophotometer arranged on the same side of the n-type SiC wafer as the light source, while the transmittance T is measured and derived using an n-type SiC wafer, a light source whose intensity spectrum of emitted light is known, and a spectrophotometer arranged on the opposite side of the n-type SiC wafer from the light source.

[0016] FIG. 1 is a graph showing the relationship between wavelength and absorptance in n-type SiC. The graph shown in FIG. 1 is a graph calculated based on the reflectance characteristic data and transmittance characteristic data of n-type SiC measured by the above-described method. FIG. 1 shows that the absorptance for light with a wavelength in the range of 415 nm to 500 nm is 45% or higher, which is higher than the absorptance for light with a wavelength longer than 500 nm. In other words, even when the workpiece includes n-type SiC, high heating efficiency can be achieved by irradiating the workpiece with heating light having a peak wavelength in the range of 415 nm to 500 nm from the light source.

[0017] It can also be seen that the absorption rate is 50% or more in the wavelength range of 420 nm to 490 nm. In other words, even when the workpiece contains n-type SiC, higher heating efficiency can be achieved by irradiating the workpiece with heating light having a peak wavelength in the range of 420 nm to 490 nm from the light source.

[0018] The window member is made of a material with high transmittance to the heating light, as described above. This transmittance is preferably 50% or more, more preferably 70% or more, and particularly preferably 80% or more. Suitable materials for the window member include synthetic quartz, fused silica, sapphire, magnesium fluoride (MgF), calcium fluoride (CaF), and barium fluoride (BaF). By using such a material for the window member, the heating light is not significantly absorbed by the window member, and the heating light from the light source can be efficiently used to heat the workpiece.

[0019] 2 is a graph showing the tendency of the light absorbance characteristics of resins used in semiconductor photoresists, as shown in the above-mentioned Non-Patent Document 1. Resins used in semiconductor photoresists include novolac resin, methacrylic resin, and PHS resin. As shown in FIG. 2, these resins are characterized by exhibiting relatively high absorbance for light with a wavelength of 300 nm or less, and novolac resin and PHS resin in particular exhibit a sudden high absorbance for light with a wavelength of 300 nm or less.

[0020] For example, when the workpiece is a SiC substrate, a semiconductor photoresist is used as a photoresist mask when ion implantation is performed on the SiC substrate. For this reason, important indices for a resin used in a semiconductor photoresist include optical transparency, chemical resistance, and solubility in a developer, and optical transparency is adjusted according to the spectrum of light emitted from a light source.

[0021] However, as mentioned above, many resins used in semiconductor photoresists exhibit high absorbance for light with wavelengths of 300 nm or less. For these reasons, it is preferable that the light source, even light emitted from an LED element, has a certain bandwidth, and that the peak wavelength of the heating light emitted be at least 370 nm or more in order to further reduce absorption by the resin. In other words, although the waveform shown in Figure 1 includes a wavelength band of 390 nm or less that exhibits relatively high absorption, light in this wavelength band is likely to be absorbed by the resin, so it is preferable to use light in a wavelength band of 400 nm or more.

[0022] The optical heating method uses heating light with a peak wavelength in the range of 420 nm to 490 nm, a wavelength range significantly shorter than conventional methods. By using heating light in this wavelength range, the heating light can be absorbed by the workpiece to a degree that can provide a heating effect, even if the workpiece contains a SiC semiconductor. This allows the workpiece to be heated without contact.

[0023] Furthermore, in the above-described light heating method, heating light having a peak wavelength in the range of 420 nm to 490 nm is used, and therefore the influence of absorption by semiconductor photoresist is reduced compared to when heating light having a peak wavelength in a shorter wavelength band is used.

[0024] The light heating method may include a step (b) of measuring the temperature of the object to be treated by using a radiation thermometer having a wavelength sensitivity range of a predetermined wavelength range of 0.7 μm to 5 μm during the step (a) to receive the light radiated from the object to be treated.

[0025] It is known that semiconductor light-emitting elements, such as LED elements, emit light in a wavelength range (main emission wavelength range) that includes the peak wavelength and has a relatively high emission intensity, as well as light in a wavelength range longer than the main emission wavelength range and having a relatively low emission intensity. While the emission intensity of this long-wavelength light is significantly lower than that of the main emission wavelength range, it exhibits an intensity slightly higher than the tail intensity when approximated by a Gaussian distribution. This long-wavelength light is derived from defects or impurity levels in the active layer that inevitably occur during the manufacture of the semiconductor light-emitting element, and is referred to as "deep light."

[0026] For example, if a light source with a peak wavelength in the range of 400 nm to 1000 nm is used as the heating light source, the wavelength range of the deep light emitted from this light source, which has a relatively high intensity, overlaps with the wavelength range of sensitivity of the radiation thermometer. As a result, part of the light from the heating light source is received by the radiation thermometer, which may result in erroneous detection of the temperature of the workpiece.

[0027] A radiation thermometer having a sensitivity wavelength range of 0.7 μm to 5 μm enables more precise temperature adjustment because it can measure the temperature of the object to be treated from a relatively low temperature range of 200° C. to 500° C. From the viewpoint of detecting the temperature with high accuracy from the initial stage after heating of the object to be treated is started, the sensitivity wavelength range of the radiation thermometer is more preferably 0.8 μm to 4 μm, and particularly preferably 1 μm to 3 μm.

[0028] The upper limit of the wavelength range of sensitivity of the radiation thermometer may be set appropriately depending on the melting point of SiC contained in the object to be treated, but this does not exclude the use of a radiation thermometer capable of measuring a temperature range higher than the melting point to measure the temperature of the object to be treated.

[0029] The optical heating device of the present invention is an optical heating device for an n-type SiC semiconductor, and is characterized by comprising: a chamber that accommodates a workpiece containing an n-type SiC semiconductor; a support member that supports the workpiece within the chamber; a light source unit that emits heating light having a peak wavelength in the range of 415 nm to 500 nm; and a window member that passes the heating light emitted from the light source unit and guides it to the workpiece.

[0030] The optical heating device described above can efficiently heat n-type SiC semiconductors, which are used in power semiconductor devices and are expected to have a particularly wide range of uses, without contact.

[0031] In the above-mentioned optical heating device, the light source unit includes a plurality of substrates on which a plurality of semiconductor light-emitting elements are mounted, and the plurality of substrates may be arranged in line symmetry, point symmetry, or rotational symmetry when viewed in the normal direction to the main surface of the substrate.

[0032] According to the above configuration, the light intensity distribution on the object to be processed is homogenized, and therefore the object to be processed can be heated uniformly.

[0033] According to the present invention, an optical heating method capable of efficiently heating a workpiece containing an n-type SiC semiconductor is realized. Also, according to the present invention, an optical heating device suitable for heating a workpiece containing an n-type SiC semiconductor is realized.

[0034] 1 is a graph showing the relationship between wavelength and absorptance in n-type SiC; 2 is a graph showing the tendency of the absorbance characteristics of resins used in semiconductor photoresists with respect to light; 3 is a cross-sectional view schematically showing the configuration of an embodiment of a light heating device; 4 is an example of the spectrum of heating light emitted from a light source unit with a peak wavelength of 460 nm; 5 is a schematic plan view of the light source unit as viewed from the -Z side; and 6 is a plan view schematically showing the configuration of a substrate.

[0035] The optical heating method according to the present invention includes a step (a) of irradiating an object to be treated, including an n-type SiC semiconductor, with heating light having a peak wavelength in the range of 420 nm to 490 nm emitted from a light source through a window member to heat the object to be treated. This optical heating method will be described below with reference to drawings of an optical heating device that is one embodiment of the method.

[0036] Note that the drawings below are all schematic illustrations, and the dimensional ratios and numbers in the drawings do not necessarily correspond to the actual dimensional ratios and numbers. Furthermore, in the following description, the workpiece is described assuming an n-type 4H—SiC semiconductor doped with nitrogen (N) as a dopant. However, as described above, the workpieces targeted by the present invention are not limited to workpieces containing a nitrogen (N)-doped n-type 4H—SiC semiconductor, but also include workpieces containing materials generally recognized in the semiconductor industry as "n-type SiC" or those that can be classified as n-type SiC. This concept is inferred based on the fact that, although it is assumed that the light absorption rate varies somewhat depending on the type of dopant and the crystal structure, it is unlikely that extreme spectral differences will appear between materials that are treated as similar products classified in the same category based on SiC.

[0037] Fig. 3 is a cross-sectional view schematically illustrating the configuration of one embodiment of the optical heating device 1. The optical heating device 1 shown in Fig. 3 includes a chamber 10 that accommodates a workpiece W1 including an n-type SiC semiconductor, a light source unit 2, and a radiation thermometer 14. The light source unit 2 includes a plurality of LED elements 11, which are a type of semiconductor light-emitting element, and a support substrate 12 on which the LED elements 11 are mounted. More specifically, the light source unit 2 in this embodiment includes a plurality of substrates 20 on which the plurality of LED elements 11 are mounted, and these plurality of substrates 20 are mounted on the support substrate 12.

[0038] In the following description, an X-Y-Z coordinate system will be referred to as appropriate, in which a plane parallel to the main surfaces (W1a, W1b) of the workpiece W1 is defined as the X-Y plane, and the normal direction to this X-Y plane is defined as the Z direction, as shown in Fig. 3. As shown in Fig. 3, the light source unit 2 and the workpiece W1 face each other in the Z direction. Using this notation, Fig. 5, which will be described later, corresponds to a schematic cross-sectional view of the light heating device 1 cut along the X-Z plane.

[0039] In the following, when expressing a direction and distinguishing between positive and negative directions, the direction will be written with a positive or negative sign, such as "+Z direction" and "-Z direction," and when expressing a direction without distinguishing between positive and negative directions, it will be simply written as "Z direction."

[0040] The light source unit 2 emits heating light L1 having a peak wavelength in the range of 415 nm to 500 nm. In this specification, the peak wavelength of the heating light L1 emitted by the light source unit 2 refers to the wavelength that exhibits the highest light intensity (light output) on the emission spectrum.

[0041] Furthermore, it is more preferable that the light source unit 2 has a main emission wavelength in the range of 415 nm to 500 nm. Specifically, it is preferable to adopt a light source unit 2 in which the wavelength band showing a light intensity of 50% or more of the peak intensity of the heating light L1 falls within the range of 415 nm to 500 nm. Furthermore, it is more preferable to adopt a light source in which the wavelength band showing a light intensity of 50% or more of the peak intensity of the heating light L1 falls within the range of 420 nm to 490 nm. This makes the light source unit 2 a light source more suitable for heat treatment of a workpiece including an n-type SiC semiconductor.

[0042] Furthermore, it is more desirable that the light source unit 2 has a wavelength range of 415 nm to 500 nm for the majority of the emitted heating light L1. Specifically, it is desirable to employ a light source unit 2 in which the wavelength band showing 90% or more of the peak intensity of the heating light L1 falls within the range of 415 nm to 500 nm. Furthermore, it is more desirable to employ a light source in which the wavelength band showing 90% or more of the peak intensity of the heating light L1 falls within the range of 420 nm to 490 nm. This makes the light source unit 2 a light source more suitable for heat treatment of a workpiece containing an n-type SiC semiconductor.

[0043] Fig. 4 shows an example of the spectrum of the heating light L1 having a peak wavelength of 460 nm emitted from the light source unit 2. In Fig. 4, the vertical axis is expressed in logarithmic scale.

[0044] According to the spectrum shown in Fig. 4, in the vicinity of 610 nm to 690 nm, which is longer than the peak wavelength, the light intensity is about 0.1% to 0.3% of the light intensity at the peak wavelength (area A1 in Fig. 4). This is light derived from impurity levels or defect levels that is inevitably generated when the light source is an LED, and corresponds to the above-mentioned "deep light."

[0045] The light source unit 2 included in the light heating device 1 has a shorter emission wavelength range than the LED lamp included in the device of Patent Document 1 described above.

[0046] As shown in FIG. 3 , the chamber 10 includes a support member 13 inside. The support member 13 supports the object W1 to be processed so that the main surfaces W1a and W1b of the object W1 are arranged on the X-Y plane. In FIG. 3 , the main surface W1b of the object W1 is arranged to face the light source unit 2. That is, circuit elements, wiring, etc. are formed on the main surface W1a or W1b, and the main surface W1b is the surface that is irradiated with the heating light L1 emitted from the light source unit 2. However, the present invention does not exclude the case where the object W1 is a bare substrate without wiring, etc., and is arranged so that the main surface W1a of the object W1 faces the light source unit 2.

[0047] The support member 13 may support the workpiece W1 in any manner as long as the main surface W1a of the workpiece W1 is positioned on the X-Y plane. For example, the support member 13 may have a plurality of pin-shaped protrusions that support the workpiece W1 at points.

[0048] As shown in FIG. 3, the chamber 10 includes a first window 10a facing the main surface W1a of the workpiece W1 supported by the support member 13, and a second window 10b facing the main surface W1b.

[0049] The first window 10a is a window used by the radiation thermometer 14 to measure the temperature of the main surface W1a of the workpiece W1. The radiation thermometer 14 is a thermometer that measures the surface temperature of an object to be measured by receiving light emitted from the object to be measured. In this embodiment, the wavelength range of sensitivity of the radiation thermometer 14 is a predetermined wavelength range ranging from 0.7 μm to 5 μm. In other words, the first window 10a is made of a material that transmits light that falls within the wavelength range of sensitivity of the radiation thermometer 14. As an example, the first window 10a is made of general quartz glass, calcium fluoride, or the like.

[0050] The wavelength sensitivity range of the radiation thermometer 14 included in the optical heating device 1 is located on the longer wavelength side than the main emission wavelength range of the heating light L1 emitted from the light source unit 2. More preferably, the lower limit of the wavelength sensitivity range of the radiation thermometer 14 is on the longer wavelength side than the wavelength showing the maximum intensity of the deep light contained in the heating light L1. As described above, the intensity of the deep light is approximately 0.1% to 0.3% of the peak intensity of the heating light L1. If the wavelength of this deep light is included in the wavelength sensitivity range of the radiation thermometer 14, there is a possibility that the temperature of the workpiece W1 will be erroneously detected.

[0051] Note that as the peak wavelength of the heating light L1 emitted from the light source unit 2 becomes shorter, the wavelength showing the maximum intensity of the deep light also shifts toward the shorter wavelength side. Therefore, in order to minimize overlap between the wavelength range of the deep light and the sensitivity wavelength range of the radiation thermometer 14, methods include shortening the emission wavelength of the light source unit 2 or lengthening the lower limit of the sensitivity wavelength range of the radiation thermometer 14. However, if the sensitivity wavelength range of the radiation thermometer 14 is shifted toward the longer wavelength side, the specific detection ability of the detection element included in the radiation thermometer 14 decreases, making it difficult to measure the temperature with high accuracy. For this reason, when heating the workpiece W1 while measuring the temperature with high accuracy within a low-temperature range, it is preferable to shorten the emission wavelength of the light source unit 2.

[0052] The second window 10b is a window member for guiding the heating light L1 emitted from the light source unit 2 to the main surface W1b of the workpiece W1. As described above, the peak wavelength of the heating light L1 is in the range of 420 nm to 490 nm. The second window 10b is made of a material that has a transmittance of 50% or more for the heating light L1. As an example, the second window 10b is made of synthetic quartz. However, the material of the second window 10b may be selected appropriately depending on the peak wavelength of the heating light L1.

[0053] 5 is a schematic plan view of the light source unit 2 as viewed from the -Z side. As shown in FIG. 5, the light source unit 2 is configured by arranging a plurality of light source regions 12a, each including a plurality of LED elements 11, on the main surface of a support substrate 12. More specifically, the light source regions 12a are formed on a substrate 20. The plurality of substrates 20 are then placed on the main surface of the support substrate 12.

[0054] 5, a plurality of substrates 20 forming the light source region 12a are arranged in a regular pattern. In the present invention, the arrangement pattern of the substrates 20 is not limited, but it is preferable that the substrates 20 are arranged symmetrically when viewed in the Z direction. Typically, it is preferable that the substrates 20 are arranged with line symmetry, point symmetry, or rotational symmetry when viewed in the Z direction. This allows the heating light L1 to be uniformly irradiated onto the main surface W1b of the workpiece W1.

[0055] FIG. 6 is a plan view schematically illustrating the configuration of the substrate 20. As shown in FIG. 6, the substrate 20 includes a plurality of LED elements 11, an anode electrode 30a, and a cathode electrode 30b. The plurality of LED elements 11 are electrically connected to the anode electrode 30a and the cathode electrode 30b. In the example shown in FIG. 6, a Zener diode 30c is mounted on the substrate 20. The Zener diode 30c is connected in parallel with the plurality of LED elements 11 between the anode electrode 30a and the cathode electrode 30b. The Zener diode 30c is arranged to prevent the LED elements 11 from being deteriorated by static electricity or surge current.

[0056] 6, the plurality of LED elements 11 mounted on the substrate 20 are connected in series and parallel. That is, some of the plurality of LED elements 11 are connected in series to each other to form an LED element group 11s, and these LED element groups 11s are connected in parallel to each other.

[0057] Each of the LED elements 11 emits heating light L1 with a peak wavelength in the range of 415 nm to 500 nm. It is preferable that the peak wavelengths of the heating light L1 emitted from the LED elements 11 are substantially identical. The term "substantially identical" here refers to allowing for wavelength deviations due to variations in the elements during the manufacturing process. Typically, the wavelength deviation may be within ±5 nm.

[0058] According to the optical heating device 1, the peak wavelength of the heating light L1 emitted from the light source 2 is in the range of 415 nm to 500 nm, so that the heating light L1 is absorbed by the workpiece W1 even if the workpiece W1 includes an n-type SiC semiconductor. This allows for non-contact heating of the workpiece W1.

[0059] Furthermore, during this light irradiation process, the temperature of the workpiece W1 can be detected by receiving light emitted from the workpiece W1 using the radiation thermometer 14. As described above, by setting the sensitivity wavelength range of the radiation thermometer 14 to a wavelength longer than the wavelength showing the maximum intensity of the deep light contained in the heating light L1, it is possible to prevent erroneous detection of the temperature of the workpiece W1 due to reception of light derived from deep light. In other words, by feeding back the detection results of the radiation thermometer 14 to a controller (not shown) that controls the light output of the light source unit 2, it is possible to heat the workpiece W1, which includes an n-type SiC semiconductor, with high precision. Note that the main emission wavelength range, including the peak wavelength of the heating light L1, is clearly outside the sensitivity wavelength range of the radiation thermometer 14.

[0060] It is more preferable that the peak wavelength of the heating light L1 be within the range of 420 nm to 490 nm, in which case the effect of suppressing the amount of ozone generated can be obtained even when the light source unit 2 is installed in the atmosphere.

[0061] Another embodiment will be described below.

[0062] <1> Fig. 5 illustrates a case where the light source region 12a is square, but this shape is merely an example. Similarly, Fig. 6 illustrates a case where the substrate 20 is rectangular, but this shape is merely an example.

[0063] 5, the plurality of substrates 20 are arranged in a staggered pattern on the support substrate 12, but the arrangement pattern of the plurality of substrates 20 is arbitrary. As another example, the plurality of substrates 20 may be arranged in a ring shape around the center 12c of the support substrate 12.

[0064] In Figure 6, the multiple LED element groups 11s mounted on the substrate 20 are all composed of the same number of LED elements 11, but the number of LED elements 11 included in the LED element groups 11s may be different, taking into account differences in voltage drop that occur depending on the respective distances from the anode electrode 30a and the cathode electrode 30b.

[0065] 3, the first window 10a for measuring the temperature with the radiation thermometer 14 is provided at a position facing the main surface W1a on the opposite side of the main surface W1b of the workpiece W1 to which the heating light L1 is irradiated. However, in the present invention, the position of the first window 10a is arbitrary. For example, the first window 10a may be provided in a sidewall of the chamber 10 or on the main surface W1b side.

[0066] In the latter case, as described above, the wavelength range to which the radiation thermometer 14 is sensitive is adjusted so as to be significantly different from the main emission wavelength range of the heating light L1 and not to overlap with the wavelength range in which the deep light exhibits maximum intensity. As a result, even if the heating light L1 is reflected by the main surface W1b of the workpiece W1, the wavelength range of the reflected light is different from the wavelength range to which the radiation thermometer 14 is sensitive, and therefore, even if the radiation thermometer 14 receives the reflected light, there is little risk of erroneously recognizing the temperature of the workpiece W1.

[0067] <3> In each of the above-described embodiments, the semiconductor light-emitting elements mounted in the light source unit 2 are all described as LED elements 11, but the light source unit 2 may also be an LD element, which is a type of semiconductor light-emitting element, or may even have a mixture of LED elements and LD elements mounted thereon.

[0068] REFERENCE SIGNS LIST 1: Light heating device 2: Light source unit 10: Chamber 10a: First window 10b: Second window 11: LED element 11s: LED element group 12: Support substrate 12a: Light source region 12c: Center of support substrate 13: Support member 14: Radiation thermometer 20: Substrate 30a: Anode electrode 30b: Cathode electrode 30c: Zener diode L1: Heating light W1: Object to be treated W1a, W1b: Main surfaces of object to be treated

Claims

1. A light heating method comprising the steps of: (a) irradiating a workpiece containing an n-type SiC semiconductor with heating light having a peak wavelength in the range of 415 nm to 500 nm emitted from a light source unit equipped with a semiconductor light emitting element through a window member to heat the workpiece.

2. The light heating method according to claim 1, wherein the heating light has a peak wavelength in the range of 420 nm to 490 nm.

3. The optical heating method according to claim 1 or 2, further comprising a step (b) of measuring the temperature of the object to be treated by a radiation thermometer having a sensitivity wavelength range within a predetermined wavelength range of 0.7 μm to 5 μm during the execution of the step (a) by receiving the light radiated from the object to be treated.

4. An optical heating device for n-type SiC semiconductor comprising: a chamber for accommodating an object to be treated including an n-type SiC semiconductor; a support member for supporting the object to be treated within the chamber; a light source unit that emits heating light having a peak wavelength in the range of 415 nm to 500 nm; and a window member that passes the heating light emitted from the light source unit and guides it to the object to be treated.

5. The optical heating device for n-type SiC semiconductors described in claim 4, characterized in that the light source unit includes a plurality of substrates on which a plurality of semiconductor light-emitting elements are mounted, and the substrates are arranged in line symmetry, point symmetry, or rotational symmetry when viewed in the normal direction to the main surface of the substrate.

Images