Heat treatment method and light heating device

Abstract

To provide a heat treatment method and light heating device that can more reliably heat a treatment target having a dielectric layer to a desired temperature by using heating light that transmits through the dielectric layer.SOLUTION: For a processing target including a laminate that is formed by stacking at least one transparent layer and transmits therethrough light in a main emitted light wavelength range of heating light, and an absorber for absorbing the light in the main emitted light wavelength range of the heating light, the main surface of the laminate is irradiated with heating light whose peak wavelength is substantially equal to a wavelength λ satisfying a predetermined formula when the thickness of a transparent layer is ti and the refractive index of the transparent layer is ni.SELECTED DRAWING: Figure 3B

Description

Technical Field

[0001] The present invention relates to a heat treatment method and an optical heating device.

Background Art

[0002] In semiconductor manufacturing processes and the like, various heat treatments such as film formation treatment, oxidation diffusion treatment, modification treatment, or annealing treatment are performed on a workpiece typified by a semiconductor wafer. In many cases, light is used when performing these heat treatments. Thus, heating a workpiece using light is referred to as "optical heating". Also, the light used for heating is referred to as "heating light". Since the heat treatment by optical heating has the advantage of being able to heat the workpiece without contact, in recent years, it has also been used for the heat treatment of a dielectric layer formed on a substrate.

[0003] Here, the transmission spectrum of the dielectric layer varies greatly depending on the composition with respect to light. For this reason, as described in Patent Document 1 below, in the heat treatment of the dielectric layer by optical heating, a method has been proposed in which light showing high intensity in a wavelength band with low transmittance is appropriately selected as the heating light based on the transmission spectrum of the dielectric layer which is the workpiece.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] Depending on the composition, the dielectric layer may be a layer that exhibits a relatively high transmittance over a wide wavelength range (for example, the entire visible light region) in part. In this case, a situation may occur where the dielectric layer does not absorb the heating light and cannot be heated to the expected temperature even when irradiated with high-intensity heating light for a long time.

[0006] Therefore, the present inventors have studied a method of indirectly heat-treating a dielectric layer by heating a substrate on which the dielectric layer is formed or a layer capable of absorbing heating light, rather than directly heating the dielectric layer, as a method of heat-treating the dielectric layer.

[0007] As a result of intensive research on a method of heating a substrate on which a dielectric layer is formed, the present inventors have found that, simply by irradiating heating light in a wavelength band selected based on the transmittance and absorptance of each layer provided in the object to be processed, the dielectric layer is often not heated to a desired temperature.

[0008] In view of the above problems, an object of the present invention is to provide a heat treatment method and a light heating device capable of more reliably heating an object to be processed provided with a dielectric layer to a desired temperature by heating light that passes through the dielectric layer.

Means for Solving the Problems

[0009] The heat treatment method of the present invention is a method of irradiating an object to be processed with heating light for heat treatment, wherein, with respect to the object to be processed including a laminate that transmits light in a main emission wavelength range of the heating light, which is formed by laminating at least one transmission layer, and an absorber that absorbs light in the main emission wavelength range of the heating light, when the thickness of the transmission layer is t i and the refractive index of the transmission layer is n i the heating light having a peak wavelength substantially the same as a wavelength λ satisfying the following formula (1) is irradiated onto a main surface of the laminate.

Equation

[0010] As used herein, the "main emission wavelength range" refers to a wavelength range with the maximum and minimum wavelengths among the wavelengths at which the intensity is half of the peak intensity in the emission spectrum as the upper and lower limits, respectively.

[0011] Also, "transmitting light in the main emission wavelength range" as used herein is intended to mean that the average transmittance for at least light belonging to the main emission wavelength range is 80% or more. And "absorbing light in the main emission wavelength range" as used herein is intended to mean that the average absorption rate for at least light belonging to the main emission wavelength range is 80% or more. Note that "transmitting light in the main emission wavelength range" and "absorbing light in the main emission wavelength range" are merely descriptions of the characteristics of the light in the main emission wavelength range of the object to be processed, and do not limit the characteristics of light in other emission wavelength ranges in any way.

[0012] Furthermore, "substantially the same wavelength" as used herein is intended to mean that the target wavelength is within ±10% of the reference wavelength.

[0013] The inventors of the present invention focused on the light reflected at the interface between the dielectric layer (laminated body) and other layers such as a layer that absorbs heating light or a substrate (also referred to as an "absorber" in this specification), and at the interface between adjacent dielectric layers of a laminated body formed by laminating a plurality of dielectric layers having different compositions (hereinafter referred to as "reflected light").

[0014] The reflected light reflected at the interface between the laminated body and the absorber provided in the object to be processed enters the laminated body due to the phase relationship and interferes with the heating light traveling toward the absorber, which may reduce the intensity of the heating light traveling in the laminated body. That is, in the conventional method of irradiating heating light in a wavelength band selected based on the transmittance and absorption rate of each layer provided in the object to be processed, there are cases where it is difficult for the heating light maintaining sufficient intensity to reach the absorber due to the generation of the above-described reflected light, resulting in a situation where the object to be processed cannot be heated as expected.

[0015] Therefore, the present inventors considered suppressing the influence of the reflected light as much as possible so that heating is performed according to the intensity of the heating light to be irradiated, and arrived at the heat treatment method described above. In addition, the present inventors also considered suppressing the reflection at the boundary of each layer by optimizing the incident angle of the heating light incident on the laminate. However, in adjusting the incident angle, it is difficult to simultaneously suppress the reflections from a plurality of boundaries, and furthermore, since there is a problem that it is necessary to control the polarization state of the heating light, a method different from this method was considered.

[0016] The condition for the reflectance at the boundary between the laminate and the absorber to become the minimum value is that the optical distance d from the incident surface to the boundary is d = (2m - 1)·λ / 4 with respect to the wavelength λ of the light traveling in the layer. Here, m is a natural number of 1 or more.

[0017] Here, the "optical distance" is, when viewed for one transmission layer, the distance converted based on the wavelength of the light traveling in air, which is obtained by the product of the thickness t of the transmission layer and the refractive index n. And when the laminate includes a plurality of transmission layers, the optical distance d of the object to be processed is the thickness t i (= t1, t2, … t N : N is the number of layers constituting the laminate) and the refractive index n i (= n1, n2, … n N ) and the sum of the products. That is, the optical distance of the laminate is expressed as in the following formula (2) regardless of the number of transmission layers constituting the laminate. Note that t i is the average thickness of the target transmission layer.

[0018]

Equation

[0019] Based on the above formula (2) and the condition for the reflectance to become the minimum value, the above formula (1) is derived.

[0020] As described above, according to the above heat treatment method, since the reflection of the heating light at the interface of each layer included in the object to be treated can be suppressed, more heating light will be absorbed by the absorber, and the object to be treated can be heated to a desired temperature.

[0021] In the above calculation, in the manufacturing process of the object to be treated, a layer that is unintentionally and unavoidably formed with a film thickness of about 1 nm or less is considered to have an extremely small influence on the propagation of the heating light. Therefore, such a layer is ignored in the calculations of the above formula (1) and the above formula (2).

[0022] The above heat treatment method may also be a method of irradiating the object to be treated, in which at least one of the transmission layers is a dielectric layer containing Hf, with the heating light.

[0023] Since the dielectric layer containing Hf tends to have a larger band gap compared to layers made of other materials, it has the characteristic that it is not absorbed unless the light has a relatively short wavelength. For example, in the case of a HfO2-based dielectric layer, since the band gap is about 6 eV, it is not much absorbed unless it is ultraviolet light with a wavelength of 200 nm or less.

[0024] That is, since the above heat treatment method can make more heating light reach the absorber, it is a suitable method for heat-treating an object to be treated in which at least one of the transmission layers is a dielectric layer containing Hf.

[0025] The above heat treatment method may also be a method of irradiating the object to be treated, which includes the transmission layer made of a ferroelectric layer and the transmission layer made of a transparent conductive layer, with the heating light.

[0026] The above heat treatment method may also be a method of irradiating the object to be treated with the heating light emitted from an LED element or an LD element.

[0027] Furthermore, the above heat treatment method A method of irradiating the object to be processed with the heating light emitted from the LED element or the LD element and having its divergence angle reduced by an optical element may also be used.

[0028] The heat treatment method described above A method of irradiating the object to be processed with the heating light having a full width at half maximum of λ / 10 or less may also be used.

[0029] The light emitted from the LED element or the LD element exhibits a narrow intensity spectrum as compared with the light emitted from other light sources such as a lamp. Such a characteristic reduces the amount of wasted light when light of a specific wavelength is required as the heating light.

[0030] In addition, the method of reducing the divergence angle of the heating light emitted from the LED element or the LD element by an optical element enables the light emitted from the LED element or the LD element to irradiate the object to be processed, and can make the incident angle of the heating light with respect to the incident surface of the object to be processed smaller. Therefore, the above method can irradiate more heating light and can further suppress reflection at the boundaries of the respective layers of the laminate.

[0031] The optical heating device of the present invention is a device for performing a heat treatment by irradiating an object to be processed with heating light, comprises a heating light source that emits the heating light, a support member that supports the object to be processed, in which at least one transmission layer is laminated and a laminate that transmits light in the main emission wavelength range of the heating light and an absorber that absorbs light in the main emission wavelength range of the heating light are laminated, such that the laminate and the heating light source face each other. The heating light source is a light source that emits heating light having a peak wavelength substantially the same as a wavelength λ that satisfies the following formula (1) when the thickness of the transmission layer is t i and the refractive index of the transmission layer is n. i

Equation

[0032] The above light heating device is provided with a mounting portion for making the heating light source detachable, and the heating light source may be configured to be replaceable according to the structure of the laminate provided in the object to be processed.

[0033] The above light heating device is provided with a lighting control unit, the heating light source has a plurality of light emitting elements that emit light with different peak wavelengths, and the lighting control unit may be configured to selectively control the lighting of the light emitting elements according to the structure of the laminate provided in the object to be processed.

Advantages of the Invention

[0034] According to the present invention, a heat treatment method and a light heating device capable of more reliably heating an object to be processed provided with the dielectric layer to a desired temperature by heating light transmitted through the dielectric layer are realized.

Brief Description of the Drawings

[0035]

Figure 1

Figure 2

Figure 3A

Figure 3B

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Embodiments for Carrying Out the Invention

[0036] Hereinafter, a heat treatment method and a light heating device of the present invention will be described with reference to the drawings. Note that each of the following drawings is schematically illustrated, and the dimensional ratios and the number of elements on the drawings do not necessarily match the actual dimensional ratios and the number of elements.

[0037] FIG. 1 is a cross-sectional view schematically showing the configuration of an embodiment of a light heating device 1. The light heating device 1 of the present embodiment includes a chamber 2, a support member 3, a light source unit 10, and a lighting control unit 20.

[0038] In the following description, as shown in FIG. 1, the direction in which the object to be processed W1 and the light source unit 10 face each other is defined as the Z direction, and a plane orthogonal to the Z direction, that is, a plane parallel to the mounting surface 11a of the substrate 11, is defined as the XY plane for explanation. In the present embodiment, there is no need to distinguish between the X direction and the Y direction that are orthogonal to each other and form the XY plane, but arbitrary directions orthogonal to each other are tentatively illustrated as the X direction and the Y direction.

[0039] Further, when expressing a direction, when distinguishing between positive and negative directions, it is described with positive and negative signs such as “+Z direction” and “-Z direction”, and when expressing a direction without distinguishing between positive and negative directions, it is simply described as “Z direction”.

[0040] The chamber 2 has a support member 3 formed inside, and an object to be heat-treated W1 is accommodated and supported inside. The chamber 2 is formed with a light-transmitting window 2a for taking in the heating light L1 emitted from the light source unit 10. When the object to be processed W1 is heat-treated, the heating light L1 taken in through the light-transmitting window 2a is irradiated onto the irradiation surface W1a, which is the +Z side main surface of the object to be processed W1 supported by the support member 3.

[0041] Note that the support member 3 is not limited to the configuration shown in FIG. 1. For example, it may be configured to support the object to be processed W1 by a plurality of pins provided on a pedestal. Further, when the light source unit 10 can be disposed in the chamber 2, the chamber 2 may not be provided with the light-transmitting window 2a. Furthermore, when heat treatment can be performed without problems in the air, the light heating device 1 may not be provided with the chamber 2.

[0042] The lighting control unit 20 in the present embodiment is connected to each light emitting element 12, and is configured to supply a current for lighting to each light emitting element 12 when performing heat treatment on the object to be processed W1. The lighting control unit 20 is, for example, an arithmetic processing device such as a microcomputer or a CPU, and further, a device combining these with an electric circuit.

[0043] As shown in FIG. 1, the light source unit 10 includes a plurality of light source units 10a, and each of the light source units 10a is a heating light source including a substrate 11, a plurality of light emitting elements 12, and a plurality of optical elements 13.

[0044] The substrate 11 is a plate-like member on which a plurality of light emitting elements 12 are placed on the placement surface 11a. In the present embodiment, the material of the substrate 11 is aluminum nitride (AlN) having relatively high thermal conductivity, but it may be configured of any material. Although not shown, a wiring pattern is formed on the placement surface 11a of the substrate 11, and power is supplied from the lighting control unit 20 to the light emitting elements 12 through the wiring pattern.

[0045] As shown in FIG. 1, the main surface 11b of the substrate 11 on the side opposite to the placement surface 11a (+Z side) is arranged in contact with the heat sink 14. Note that when the configuration is such that the heat generated by the light source unit 10a can be sufficiently dissipated by natural heat dissipation, the light source unit 10 may not be provided with the heat sink 14.

[0046] The light-emitting element 12 in this embodiment is an LED element with a peak wavelength of 395 nm and a full width at half maximum of 7 nm. And in this embodiment, about 200 light-emitting elements 12 are mounted on the mounting surface 11a of one substrate 11 in the light source unit 10.

[0047] The light-emitting element 12 may be an LED element, an LD element, a phosphor element, or a combination thereof. However, the peak wavelength of the heating light L1 emitted is selected according to the structure of the laminate A1 included in the object to be processed W1. Also, from the viewpoint of efficiently heating the object to be processed W1, the full width at half maximum of the heating light L1 emitted from the light-emitting element 12 is preferably 1 / 10 or less of λ derived from the above formula (1), but it may be outside this range. Note that as the light-emitting element 12 with a small full width at half maximum, an LED element or an LD element is suitable.

[0048] As shown in FIG. 1, the optical element 13 in this embodiment is a lens provided corresponding to each of the plurality of light-emitting elements 12, and reduces the divergence angle of the heating light L1 emitted from the light-emitting element 12.

[0049] In FIG. 1, for the sake of illustration, the heating light L1 emitted from the optical element 13 is illustrated as parallel light along the Z direction. However, the optical element 13 does not need to be an element that completely collimates the heating light L1 emitted from the light-emitting element 12. Also, in each drawing, the optical element 13 is illustrated in a floating state at a position away from the light source unit 10. However, the actual optical element 13 is supported by a support (not shown) fixed to the substrate 11, the heat sink 14, etc. Further, the optical element 13 may be directly formed on the light-emitting surface of the light-emitting element 12.

[0050] As the optical element 13, in addition to a lens, for example, an optical system such as a prism or a concave mirror can be adopted. However, from the viewpoint of further reducing the amount of the heating light L1 reflected inside the object to be processed W1, the incident angle of the heating light L1 on the irradiation surface W1a of the object to be processed W1 is preferably close to 0°.

[0051] In addition, only one optical element 13 may be provided for the plurality of light-emitting elements 12. FIG. 2 is a cross-sectional view schematically showing the configuration of another embodiment of the optical heating device 1 different from FIG. 1. As shown in FIG. 2, if the divergence angle of the heating light L1 emitted from the light-emitting element 12 is reduced and the irradiation surface W1a of the object to be processed W1 is irradiated, one light source unit 10a may have a configuration including a plurality of light-emitting elements 12 and one optical element 13. Further, when the divergence angle of the light emitted from the light-emitting element 12 is sufficiently small, the light source unit 10 may not include the optical element 13.

[0052] Here, a method for selecting the peak wavelength of the heating light L1 will be described. In practice, the heating light L1 enters the irradiation surface W1a of the object to be processed W1 at various incident angles. For the sake of convenience of explanation, the heating light L1 incident at an incident angle of 0° will be described.

[0053] FIG. 3A is an enlarged view of a part of the object to be processed W1, and FIG. 3B is an enlarged view of the laminate A1 of the object to be processed W1. As shown in FIG. 3A, the object to be processed W1 includes a laminate A1 in which a plurality of transmission layers (C1, C2, C3, C4) are laminated, and a base material A2.

[0054] The laminate A1 in the present embodiment is configured by laminating four transmission layers that transmit light in the main emission wavelength range of the heating light L1. Specifically, the transmission layer C1 is a SiO2 layer, the transmission layers (C2, C4) are ITO layers which are a kind of transparent conductive layer, and the transmission layer C3 is a Hf 0.5 Zr 0.5 O2 layer. The thickness t i and the refractive index n i are as shown in Table 1 below.

[0055]

Table 1

[0056] Here, the thickness t i and the refractive index ni It is measured, for example, using a spectroscopic ellipsometer. Although the thickness of C1 is 0 nm in Table 1, in the case of the structure of Table 1, there is actually no C1 layer, and it is composed of three layers, C2 to C4. For the sake of consistency with the notation in the case of the four-layer structure with C1 provided later, C1 is described as 0 nm in the table for convenience. Also, the refractive index n i slightly varies depending on the wavelength, and the values in the table are described with the value at λ = 400 nm as representative as shown in parentheses.

[0057] Further, the base material A2 in the present embodiment is a Si substrate, which corresponds to an absorber that absorbs light in the main emission wavelength range of the heating light L1 and generates heat.

[0058] The heating light L1 emitted from the light source unit 10 enters the irradiation surface W1a of the object to be processed W1 as shown in FIG. 3A, and travels toward the base material A2 while passing through the laminate A1.

[0059] Here, as described above, the condition for the reflectance at the boundary of each layer to be a minimum value (theoretically 0) is that the wavelength λ1 of the heating light L1 is substantially the same as the wavelength derived from the above formula (1). Here, for the sake of caution, the above formula (1) is reproduced.

[0060]

Equation

[0061] In the present embodiment, with m = 1, from the above formula (1), λ is derived as 371.6 nm. Therefore, as the light-emitting element 12, an LED element that emits the heating light L1 with a peak wavelength λ1 of 395 nm, which is considered to be substantially the same as this, is adopted. Since the respective refractive indices (n1, n2, n3, n4) of each transmission layer (C1, C2, C3, C4) change considerably depending on the wavelength of the target light, in actual design, as described below, it is preferable to perform a process of specifying the substantial optimum value by measuring the reflectance for each wavelength of the object to be processed W1.

[0062] Here, since samples of several objects to be processed were prepared and spectra with the reflectance on the vertical axis and the wavelength on the horizontal axis were obtained for each sample, the method of selecting the heating light L1 (light emitting element 12) will be described while comparing with the structure of each sample.

[0063] Example 1 is the object to be processed W1 having the configuration as shown in Table 1 above. Example 2 is an object to be processed having each transmission layer (C1, C2, C3, C4) shown in Table 2 below, and Example 3 is an object to be processed having each transmission layer (C1, C2, C3, C4) shown in Table 3 below. Note that the optical distance d in each sample is 195.6 nm for Example 2 and 278.0 nm for Example 3. Also, the refractive index n i slightly varies depending on the wavelength as described in Example 1, but for the following numbers 2 and the values in Table 3 below, as shown in parentheses, the values at λ = 850 nm and 380 nm are described as representatives respectively.

[0064]

Table 2

[0065]

Table 3

[0066] Figures 4 to 6 are graphs of the reflectance of each example sample. Note that these graphs are reflection spectra obtained by measuring each sample with a spectroreflectometer.

[0067] The minimum values of the reflectance read from each graph in Figures 4 to 6 are 400 nm for Example 1, 260 nm and 850 nm for Example 2, and 370 nm and 1100 nm for Example 3.

[0068] Regarding Example 1, as described above, since λ is derived to be 371.8 nm, the light emitting element 12 employs an LED element that emits heating light L1 with a peak wavelength λ1 of 400 nm, which is considered to be substantially the same as this.

[0069] Regarding Example 2, when m = 1, λ is derived to be 782.5 nm, and when m = 2, λ is derived to be 260.8 nm. Regarding Example 3, when m = 1, λ is derived to be 1113.0 nm, and when m = 2, λ is derived to be 371.0 nm. That is, also for Example 2 and Example 3, it is confirmed that the wavelength derived from the above formula (1) and the wavelength at which the reflectance becomes a minimum value actually measured are substantially the same.

[0070] Note that when the value of m is further increased, the derived wavelength λ becomes a shorter wavelength. However, light-emitting elements that emit light in a wavelength band with a peak wavelength of 200 nm or less are difficult to obtain. Also, it is not impossible to achieve, but it is not realistic to realize an intensity sufficient to heat the object to be processed W1 with the light in that wavelength range.

[0071] And the transmission layers (C1, C2, C3, C4) are required to transmit light in the main emission wavelength range of the heating light L1. Considering these circumstances, the value of m can be arbitrarily adopted, but it is preferably "1" or "2".

[0072] From the above, according to the light heating device 1 having the above configuration and the heating treatment method implemented by the light heating device 1, reflection at the boundary B1 between the laminate A1 and the base material A2 can be suppressed as much as possible, and the heating light L1 can be more absorbed by the base material A2. Therefore, the laminate A1 can be heated efficiently.

[0073] Note that in the above embodiment, the transmission layers (C1, C2, C3, C4) of the laminate A1 are SiO2 layers, ITO layers, Hf 0.5 O 0.5Although the description has been made on the premise that it is a layer, the optical heating device 1 having the above-described configuration and the heat treatment method implemented by the optical heating device 1 can also be applied to a laminate including other transmission layers. For example, the optical heating device 1 having the above-described configuration and the heat treatment method implemented by the optical heating device 1 can also be applied to a transparent resin layer, a glass layer, and a transparent conductive layer made of a material other than the above-described respective layers. Further, the optical heating device 1 having the above-described configuration and the heat treatment method implemented by the optical heating device 1 can also be applied to a laminate including one of the above-described transmission layers.

[0074] [Another Embodiment] Hereinafter, another embodiment will be described.

[0075] 〈1〉 FIG. 7 is a drawing showing a configuration example of a workpiece W1. As shown in FIG. 7, the optical heating device 1 described above and the heat treatment method implemented by the optical heating device 1 can also be applied to a workpiece W1 provided with an absorption layer A3 that absorbs heating light L1 and generates heat on the laminate A1 side (+Z) rather than the base material A2.

[0076] 〈2〉 The above-described embodiment has been described on the premise that the plurality of light-emitting elements 12 mounted on the light source unit 10 all emit light having the same peak wavelength. However, the light source unit 10 may be mixed with light-emitting elements 12 having different peak wavelengths of the emitted light. Further, the light-emitting elements 12 having different peak wavelengths of the emitted light may be mixed in the light source unit 10a, or may be classified and mounted so that the peak wavelengths of the emitted light are unified for each light source unit 10a.

[0077] Then, the lighting control unit 20 may be configured to perform lighting control on the light source unit 10 having the above-described configuration so as to irradiate the irradiation surface W1a of the workpiece W1 with light in a desired wavelength range as the heating light L1.

[0078] FIG. 8 is a cross-sectional view schematically showing the configuration of the light source unit 10 in another embodiment of the light heating device 1. As shown in FIG. 8, the light heating device 1 includes a mounting portion 30 to which the light source unit 10 is detachably attached, and the light source unit 10 may be configured to be replaceable so that light in a desired wavelength range can be irradiated as heating light L1 onto the irradiation surface W1a of the object to be processed W1.

[0079] Note that the light source unit 10 may be configured such that not only the entire light source unit 10a but also the entire light source unit 10 is replaceable. Further, the configuration of the mounting portion 30 is not limited to the configuration shown in FIG. 8. For example, a groove corresponding to the substrate 11 of the light source unit 10a may be formed, and the light source unit 10a may be mounted by inserting the substrate 11 into the groove.

[0080] 〈3〉 The configuration included in the above-described light heating device 1 is merely an example, and the present invention is not limited to each of the illustrated configurations.

Description of Reference Numerals

[0081] 1: Light heating device 2: Chamber 2a: Translucent window 3: Support member 10: Light source unit 10a: Light source unit 11: Substrate 11a: Mounting surface 11b: Main surface 12: Light emitting element 13: Optical element 14: Heat sink 20: Lighting control unit 30: Mounting portion A1: Laminate A2: Base material A3: Absorbing layer L1: Heating light W1: Object to be processed W1a: Irradiation surface

Claims

1. A method for heat-treating a workpiece by irradiating the workpiece with heating light, A laminate having at least one transparent layer laminated thereon and transmitting light in the main emission wavelength range of the heating light, and an absorber that absorbs light in the main emission wavelength range of the heating light, with respect to the object to be treated, the thickness of the transparent layer is t i , the refractive index of the transparent layer is n i When it is set as, the heat treatment method characterized by irradiating the main surface of the said laminated body with the said heating light which is substantially the same as the wavelength λ whose peak wavelength satisfy |s the following formula (1). 【Number 1】 (where i is one or more natural numbers corresponding to the stacking order from the irradiation surface side of each transmission layer constituting the laminate, and m is a natural number of 1 or more).

2. The heat treatment method according to claim 1, wherein the heating light is irradiated onto the workpiece in which at least one of the transmission layers is a dielectric layer containing Hf.

3. The heat treatment method according to claim 1, wherein the heating light is irradiated onto the workpiece including the transmission layer made of a ferroelectric layer and the transmission layer made of a transparent conductive layer.

4. The heat treatment method according to any one of claims 1 to 3, wherein the heating light emitted from an LED element or an LD element is irradiated onto the workpiece.

5. The heat treatment method according to claim 4, wherein the heating light emitted from the LED element or the LD element and having a divergence angle reduced by an optical element is irradiated onto the workpiece.

6. The heat treatment method according to claim 1, wherein the heating light having a full width at half maximum of λ / 10 or less is irradiated onto the workpiece.

7. An apparatus for heat-treating a workpiece by irradiating the workpiece with heating light, a heating light source that emits the heating light, a support member that supports a workpiece in which a laminate that transmits light in the main emission wavelength range of the heating light and an absorber that absorbs light in the main emission wavelength range of the heating light are laminated, with at least one transmission layer laminated, such that the laminate and the heating light source face each other, The light source for heating has a thickness t of the transmission layer i , a refractive index n of the transmission layer i When the peak wavelength is substantially the same as the wavelength λ that satisfies the following formula (1), it is a light heating device characterized by emitting the heating light. 【Number 2】 (where i is a natural number corresponding to the stacking order counted from the irradiation surface side of each transmission layer constituting the laminate, and m is a natural number of 1 or more).

8. The optical heating apparatus according to claim 7, further comprising a mounting portion for making the heating light source detachable, and being configured such that the heating light source is replaceable according to the structure of the laminate included in the workpiece.

9. comprising a lighting control unit, wherein the heating light source has a plurality of light-emitting elements that emit light having different peak wavelengths, and the lighting control unit selectively controls lighting of the light-emitting elements according to the structure of the laminate included in the workpiece.

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