Temperature measurement method, temperature relational expression derivation method, and temperature measurement device

Abstract

The invention discloses a temperature measuring method, a temperature relational expression deriving method and a temperature measuring device, and the temperature relational expression deriving method comprises the following steps: a light irradiation step, heating light used for heating a target substance and measuring light used for detecting the reflectivity change of the target substance caused by the heating light are irradiated to the same point of the target substance; a light detection step of detecting the incident light and reflected light intensity of the measurement light; and a calculation step of deriving a temperature relational expression based on the reflectance of the target substance using the value detected in the light detection step.

Description

Technical Field

[0001] The invention relates to a temperature measuring method and a temperature measuring device for measuring the surface temperature of a substance. Background Art

[0002] It is important to form a uniform process temperature distribution over a wide range in equipment that manufactures and inspects semiconductor chips under various environmental conditions. Therefore, accurate temperature measurement is required to control the process to form a uniform temperature distribution.

[0003] For example, in a substrate heat treatment process, the substrate can be placed in a high-speed heat treatment device and exposed to a pulse beam during the process. At this time, the surface of the area exposed to the pulse beam can be heated to a high temperature of more than 1000°C in a short time of less than 1ms to more than 1μs.

[0004] Due to the high temperature, structural changes can be generated in the area exposed to the pulsed beam. The extent of the structural changes depends on the temperature, so it is particularly important to accurately monitor the temperature during the heat treatment process. Summary of the invention

[0005] The present invention provides a temperature measurement method and a temperature measurement device which can measure the surface temperature change of a rapidly changing target substance with high accuracy.

[0006] In addition, the present invention provides a temperature measurement method and a temperature relationship equation of a temperature measurement device that can be applied to measure the surface temperature change of a target substance that changes rapidly with high accuracy.

[0007] The problems to be solved by the present invention are not limited to the above-mentioned problems, and those having ordinary knowledge in the technical field to which the present invention belongs can clearly understand problems not mentioned from this specification and the attached drawings.

[0008] According to an embodiment of the present invention, there is provided a temperature measuring device, comprising: a measuring light source, for irradiating a measuring light to a point on the surface of a target material in order to measure the surface temperature of a target material; an optical system, for forming a light path of the measuring light toward the surface of the target material; a plurality of detection components, for detecting the incident light and reflected light intensity of the measuring light; and a processing unit, for calculating the reflectivity of the target material based on the detection value of each of the plurality of detection components, and determining the surface temperature of the target material based on the reflectivity.

[0009] In one embodiment, the optical system may include a polarization separator for separating the reflected light into p-polarized reflected light and s-polarized reflected light.

[0010] In one embodiment, the plurality of detection components may include: a first detection component that outputs the intensity of the incident light; a second detection component that outputs the intensity of the p-polarized reflected light; and a third detection component that outputs the intensity of the s-polarized reflected light.

[0011] In one embodiment, the processing unit may calculate the polarization reflectivity of the target substance based on the detection value of each of the plurality of detection components.

[0012] In one embodiment, the processing unit may apply the polarization reflectivity of the target substance to a stored temperature relationship to determine the surface temperature of the target substance.

[0013] In one embodiment, the temperature relationship equation may be a linear relationship equation derived from the polarization reflectivity of the target substance at room temperature and the polarization reflectivity of the target substance at a melting point of the target substance.

[0014] In one embodiment, the temperature relationship equation may be derived by irradiating the surface of the target substance with heating light that can rapidly change the temperature of the surface of the target substance to a melting point of the target substance together with the measurement light.

[0015] In one embodiment, the temperature measuring device may further include: an output device for outputting the surface temperature change of the target substance over time.

[0016] According to one embodiment of the present invention, a method for deriving a temperature relationship equation is provided, comprising: a light irradiation step, irradiating a heating light for heating a target substance and a measuring light for detecting a change in the reflectivity of the target substance caused by the heating light to the same point of the target substance; a light detection step, detecting the incident light and reflected light intensity of the measuring light; and a calculation step, deriving a temperature relationship equation based on the reflectivity of the target substance using the value detected in the light detection step. In this case, the heating light may be a pulsed light beam that rapidly changes the temperature of the surface of the target substance to the melting point of the target substance.

[0017] In one embodiment, the light detection step may separate the reflected light into p-polarization and s-polarization to detect the intensities thereof.

[0018] In one embodiment, the calculating step may use a value detected from at least one of p-polarization and s-polarization of the reflected light according to a material type of the target material surface.

[0019] In one embodiment, the calculation step may include: a first calculation step of calculating the polarization reflectivity of the target substance; and a second calculation step of deriving a temperature relationship equation of the target substance based on the polarization reflectivity.

[0020] In one embodiment, the second calculation step may derive a linear temperature relationship from the polarization reflectivity of the target substance when it is at room temperature and the polarization reflectivity of the target substance when the surface temperature reaches a melting point.

[0021] In one embodiment, the graph showing the p-polarized reflectivity of the target substance over time may include three inflection points in a maximum value region or a minimum value region according to at least one of the type of the target substance and the incident angle of the measurement light.

[0022] In one embodiment, when the three inflection points are included in the maximum value region of the graph, the polarization reflectivity when the surface temperature of the target substance reaches the melting point may be the maximum value of the graph.

[0023] In one embodiment, when the three inflection points are included in the minimum value region of the curve graph, the polarization reflectivity when the surface temperature of the target substance reaches the melting point may be the minimum value of the curve graph.

[0024] According to one embodiment of the present invention, there is provided a temperature measurement method, comprising: a step of calculating and storing a temperature relationship equation based on the reflectivity of a target substance; a step of irradiating a point of the target substance with a measurement light for measuring the surface temperature of the target substance obliquely incident on the target substance; a light detection step of detecting the incident light and reflected light intensities of the measurement light obliquely incident on the target substance; and a calculation step of calculating the surface temperature of the target substance by applying the value detected in the light detection step to the temperature relationship equation, wherein the light detection step separates the reflected light into p-polarization and s-polarization to detect their intensities.

[0025] In one embodiment, the temperature relationship equation may be a linear relationship equation derived from the polarization reflectivity of the target substance at room temperature and the polarization reflectivity of the target substance at a melting point of the target substance.

[0026] In one embodiment, the calculation step may be that the calculation step uses a value detected from at least one of the p-polarization and the s-polarization of the reflected light according to the material type of the surface of the target material, and the calculation step includes: a first calculation step of calculating the polarization reflectivity of the target material; and a second calculation step of applying the polarization reflectivity calculated in the first calculation step to the temperature relationship to calculate the surface temperature of the target material.

[0027] In one embodiment, the temperature measurement method may further include: an output step of outputting the surface temperature change of the target substance generated over time.

[0028] According to an embodiment of the present invention, the temperature relationship can be calculated based on the reflectivity of the target material at room temperature and melting point, and applied to the temperature measurement technology, so that the surface temperature change of the rapidly changing target material can be accurately and quickly calculated.

[0029] In addition, after the reflected light is separated into p-polarization and s-polarization, the intensity thereof is detected, so that the detected value can be selectively applied to temperature measurement according to the type of the substance to be measured.

[0030] The effects of the present invention are not limited to the above-mentioned effects, and those having ordinary knowledge in the technical field to which the present invention pertains can clearly understand unmentioned effects from this specification and the attached drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 FIG. 1 is a diagram schematically showing the structure of a temperature measuring device according to an embodiment of the present invention.

[0032] Figure 2 FIG. 1 is a flow chart schematically showing a method for deriving a temperature relationship equation according to an embodiment of the present invention.

[0033] Figures 3 to 6 The schematic diagram shows the use of Figure 1 Devices and Figure 2 Example of a graph derived using the method.

[0034] Figure 7 FIG. 1 is a flow chart schematically showing a temperature measurement method according to an embodiment of the present invention.

[0035] (Explanation of Reference Numerals)

[0036] 100: Temperature measuring device

[0037] T: Target substance

[0038] H: Heating light source

[0039] 110: Measuring light sources

[0040] 200: Optical system

[0041] 250: Polarization Splitter

[0042] 310, 320, 330: Detection components

[0043] 400: Processing unit DETAILED DESCRIPTION

[0044] Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that a person having ordinary knowledge in the technical field to which the present invention belongs can easily implement the present invention. The present invention can be implemented in various forms and is not limited to the embodiments described here.

[0045] In order to clearly describe the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

[0046] In addition, in a plurality of embodiments, components having the same configuration are denoted by the same reference numerals and only representative embodiments are described, and in other embodiments, only the representative embodiments and other configurations are described.

[0047] Throughout the specification, when a part is "connected (or coupled)" to another part, it includes not only the case of "direct connection (or coupling)" but also the case of "indirect connection (or coupling)" via other parts. In addition, when a part "includes" a certain constituent element, it means that other constituent elements may be included, rather than excluding other constituent elements, unless otherwise specifically stated.

[0048] Unless otherwise defined, all terms used herein, including technical terms or scientific terms, have the same meanings as those generally understood by persons skilled in the art to which the present invention belongs. Terms such as terms defined in commonly used dictionaries should be interpreted as having the same meanings as those in the context of the relevant technology, and should not be interpreted as idealized or overly formalized meanings unless explicitly defined in this application.

[0049] Figure 1 FIG. 1 is a diagram schematically and illustratively showing the structure of a temperature measurement device according to an embodiment of the present invention.

[0050] The temperature measuring device 100 according to the present invention can be applied to a semiconductor manufacturing process. More specifically, the temperature measuring device 100 according to the present invention can be a device for measuring the surface temperature of a substrate heated by a rapid thermal source. Therefore, the target material T to be measured for the surface temperature can be a substrate. For example, the substrate is a wafer. As a typical example, the substrate can be a silicon wafer or a composite wafer frequently used in the semiconductor equipment industry. The substrate can be heat treated in a state placed inside a process chamber configured for heat treatment.

[0051] The temperature measurement device 100 according to an embodiment of the present invention uses a technique for measuring the surface temperature of a target substance using polarization reflectance recovered from the surface of the target substance whose surface temperature is to be measured.

[0052] The vibration movement of particles (atoms) constituting solid crystals increases with the increase in temperature, and the available volume of the particles increases due to the increase in vibration energy, resulting in thermal expansion. In addition, when the temperature increases in the same unit volume, the polarizability of the particles also increases (related to the complex dielectric constant). Therefore, it is observed that the thermal expansion and polarizability changes depending on the temperature affect the refractive index and reflectivity when the light source is injected, and therefore their relationship is utilized.

[0053] Reference Figure 1 , the temperature measuring device 100 according to the present invention may include a measuring light source 110 , an optical system 200 , a plurality of detection components and a processing unit 400 .

[0054] In order to measure the temperature change of the target material T passing through the heating light source H, the measuring light source 110 may irradiate the measuring light to the same point reached by the heating light from the heating light source H. As an example, the heating light source H may be a high-speed heat generating source that generates a pulse wave, and the measuring light source 110 may be a laser that generates a continuous wave (CW).

[0055] On the other hand, in order to improve the temperature matching of the measurement result value, the measurement light source 110 used in the temperature measurement device 100 preferably has a wavelength region with high reflectivity for the measurement element, i.e., the target material T. In addition, considering the optical power loss caused by the components for processing the reflected light, it is preferred to have high optical power. In addition, the relative intensity noise (RIN%) is small or noise filtering is easy. When calibrating (calibration) equivalent to the normal temperature (reference temperature) of the temperature measurement range and the output voltage value at the melting point (equivalent to the intensity of the reflected light), the more temperature correction points, the better.

[0056] The optical system 200 is used to form an optical path for the measurement light, and directs the measurement light received from the measurement light source 110 toward the surface of the target substance T. The optical system 200 may include, for example, a wavelength plate wp for generating an optical path difference of the measurement light and at least one focusing member c for focusing the measurement light on the surface of the target substance T.

[0057] In addition, the optical system 200 may further include a plurality of mirror components m for providing an appropriate direction to the measuring light. The measuring light may be incident on the surface of the target material T through the mirror component m disposed at an appropriate position at an appropriate angle, and the reflected light reflected from the surface of the target material T may reach the detection component to be described later through another mirror component m' disposed at an appropriate position at an appropriate angle.

[0058] The optical system 200 may further include a polarization separator 250 that separates the reflected light reflected from the surface of the target material T into two polarizations, specifically, into s-polarized reflected light and p-polarized reflected light. The polarization separator 250 can separate the p-polarization with a large reflectivity variation by polarization separation of the reflected light, thereby improving the temperature accuracy of the measurement result. The polarization separator 250 is configured between the target material T and the detection component for detecting the reflected light. In other words, the reflected light reaches the detection component configured to detect the reflected light after being separated by the polarization separator 250. For example, the polarization separator can be a polarization beam splitter. Alternatively, the polarization separator can be a Wollaston prism.

[0059] On the other hand, although not shown in detail, a polarization separator may also be applied between the measurement light source 110 and the target material T. The polarization separator applied between the measurement light source 110 and the target material T separates a portion of the measurement light incident on the target material T, and the separated portion of the measurement light may be detected and analyzed as reference light. The reference light may later be used as a reference for intensity correction of reflected light and minimization of common noise (noise).

[0060] Preferably, the optical system 200 is configured to obliquely incident the measuring light onto the surface of the target material T. The angle at which the measuring light is incident may be any angle except the Brewster angle (angle at which the reflectivity is 0%). In order to improve the temperature matching of the temperature measurement value, the optical system is preferably configured so that the incident angle of the measuring light may have a peripheral (adjacent) incident angle of the Brewster angle (angle at which the reflectivity is 0%) having the maximum value of the p-polarized reflectivity variation amplitude.

[0061] A plurality of detection components may be provided, and an electrical signal showing the intensity of the incident light and the measurement light may be generated. More specifically, the detection component may detect the intensity of the reflected light reflected from the target material T by the measurement light incident on the target material T. As an example, the detection component may be a photodiode PD that detects the intensity of the reflected polarization through a voltage signal. According to an embodiment of the present invention, the detection component may include a first detection component 310 that detects the intensity of the incident light, a second detection component 320 that detects the intensity of the s-polarized reflected light of the reflected light separated by the polarization separator, and a third detection component 330 that outputs the intensity of the p-polarized reflected light. The output values ​​of the first detection component 310, the second detection component 320, and the third detection component 330 may be transmitted to the processing unit 400.

[0062] The processing unit 400 can determine the surface temperature of the target material based on the detection value of each of the multiple detection components. Specifically, the processing unit 400 can calculate the polarization reflectivity of the target material based on the detection value of each of the multiple detection components, and determine the surface temperature of the target material T from the calculated polarization reflectivity. In addition, the processing unit 400 can selectively use one of the p-polarization and s-polarization of the reflected light according to the material type on the surface of the target material T. The reflectivity can be the intensity of the reflected light divided by the intensity of the incident light, so the detection value of the second detection component 320 or the third detection component 330 is divided by the value of the first detection component 310, thereby calculating the p-polarization reflectivity or s-polarization reflectivity of the target material T.

[0063] In order to determine the surface temperature of the target material T from the polarization reflectivity, the processing unit 400 may apply the calculated polarization reflectivity of the target material T to the temperature relationship. At this time, the temperature relationship may be derived by the temperature measurement device 100 and stored in the processing unit 400 before the temperature measurement device 100 is used for surface temperature measurement.

[0064] The temperature relationship equation for measuring the surface temperature of the target substance T can be derived from the polarization reflectivity of the target substance T at room temperature and the polarization reflectivity of the target substance T at the melting point of the target substance T. The method for deriving the temperature relationship equation according to one embodiment of the present invention is as follows: Figure 2 shown.

[0065] The temperature relationship derivation method according to an embodiment of the present invention may include a light irradiation step S1 , a light detection step S2 , and a calculation step S3 .

[0066] The light irradiation step S1 is a step of irradiating a heating light for heating the target substance T and a measuring light for detecting a change in the reflectivity of the target substance T caused by the heating light to a point of the target substance T. At this time, the heating light irradiated to the target substance T is a pulse light beam having a power capable of rapidly changing the surface temperature of the target substance T to a melting point.

[0067] The light detection step S2 is a step of detecting the intensity of incident light and reflected light of the measurement light. The intensity of the reflected light can be separated into p-polarization and s-polarization and detected. The light detection step S2 can be performed by a plurality of detection components 310 , 320 , 330 included in the optical system 200 .

[0068] The calculation step S3 is a step of deriving a temperature relationship equation based on the reflectivity of the target material T using the detection values ​​of each of the plurality of detection components. The calculation step S3 may include a first calculation step S31 for calculating the polarization reflectivity of the target material T and a second calculation step S32 for deriving the temperature relationship equation of the target material T based on the polarization reflectivity calculated in the first calculation step S31. At this time, one polarization reflectivity of the p-polarization and the s-polarization may be selectively calculated and used according to the material type of the surface of the target material.

[0069] The reflectivity refers to the value obtained by dividing the intensity of reflected light by the intensity of incident light, and therefore the first calculation step S31 is a step of calculating the p-polarized reflectivity and s-polarized reflectivity of the target material T using the values ​​detected in the light detection step S2. The p-polarized reflectivity can be obtained by dividing the detection value of the second detection component 320 that detects the voltage signal (intensity) of the p-polarized reflected light by the detection value of the first detection component 310 that detects the voltage signal (intensity) of the incident light, and the s-polarized reflectivity can be obtained by dividing the detection value of the third detection component 330 that detects the voltage signal (intensity) of the s-polarized reflected light by the detection value of the first detection component 310 that detects the voltage signal (intensity) of the incident light.

[0070] The second calculation step S32 is a step of deriving a temperature relationship from the polarization reflectivity of the target substance T at room temperature and the polarization reflectivity of the target substance T at the melting point. As an example, when the second calculation step S32 is at room temperature, the temperature relationship can be derived from the p-polarization reflectivity of the target substance T and the p-polarization reflectivity of the target substance T at the melting point.

[0071] When the target substance T exists in a solid state, the reflectivity change is proportional to the temperature change. The reflectivity can be calculated by the first calculation step S31, and the normal temperature and the melting point temperature of the target substance T are known values. Therefore, a linear temperature relationship can be derived from the polarization reflectivity of the target substance T at normal temperature and the polarization reflectivity of the target substance T at the melting point.

[0072] As the value calculated in the first calculation step S31, it can be Figure 3 or Figure 4 Thus, the change in polarization reflectance of the target material T over time, which occurs over time, is shown in a graph. Figure 3 The graph shows the change in p-polarized reflectivity over time observed when the target material is a silicon (Si) substrate and measurement light is irradiated at an incident angle of less than the Brewster angle (the angle when the reflectivity is 0, 75.5° in the case of silicon). Figure 4The p-polarized reflectivity change over time observed when the target material is a silicon substrate and the measuring light is irradiated at an incident angle above the Brewster angle is shown. Thus, the inversion of the time-reflectivity graph based on the Brewster angle may differ depending on the type of the target material T.

[0073] For example, in the case of a part of the target material T, when the incident angle of the measuring light is greater than the Brewster angle, the following is shown: Figure 3 In the case of such a graph, when the incident angle of the measuring light is below the Brewster angle, the following is also shown: Figure 4 That is, depending on the type of target material and the incident angle of the measurement light, the curve of the change of polarization reflectivity over time can be as follows: Figure 3 or Figure 4 Shown like that.

[0074] According to one embodiment of the present invention, for any target substance, a pulsed light beam as heating light is irradiated onto the surface of the target substance so that the temperature of the surface of the target substance changes rapidly to the melting point of the target substance, and an inspection light is incident at any incident angle, so that the output time-reflectivity curve is different from the output time-reflectivity curve. Figure 3 In the same case, the polarization reflectivity at the melting point of the target substance T may be the maximum value among the values ​​calculated in the first calculation step S31. Specifically, the maximum value of the time-reflectivity curve for one pulse output of the heating light may be the polarization reflectivity of the target substance T at the melting point of the target substance T.

[0075] On the contrary, according to one embodiment of the present invention, for any target substance, a pulsed light beam as heating light is irradiated onto the surface of the target substance so that the temperature of the surface of the target substance changes rapidly to the melting point of the target substance, and a thermal inspection light is irradiated at any incident angle, so that the outputted time-reflectivity curve is the same as Figure 4 In the same case, the polarization reflectivity of the target substance T at the melting point of the target substance T may be the minimum value among the values ​​calculated in the first calculation step S31. Specifically, the minimum value of the time-reflectivity curve for one pulse output of the heating light may be the polarization reflectivity of the target substance T at the melting point of the target substance T.

[0076] The polarization reflectivity of the target material at room temperature can be calculated by irradiating the target material T with only the measurement light without the heating light. In addition, the polarization reflectivity of the target material at room temperature can be derived from the starting area of ​​the linear curve shown in the time-reflectivity curve output according to one embodiment of the present invention. For example, Figure 3 as well as Figure 4As shown, even when there is no specific starting point of the linear graph, the polarization reflectivity of the target material at room temperature can be estimated using the intermediate value of the values ​​existing in the starting area of ​​the graph.

[0077] On the other hand, when the temperature matching of the temperature measuring device 100 is high, the maximum value region or the minimum value region of the time-reflectivity curve may include three inflection points (refer to Figure 5 as well as Figure 6 ). The higher the temperature matching of the temperature measuring device 100, the more clearly the three inflection points can be observed. The polarized reflectivity at the melting point of the target substance T can be confirmed from the three inflection points included in the maximum value region or the minimum value region. Specifically, among the three inflection points, as time passes, the first inflection point shown first can be reached when the surface temperature of the target substance T reaches the melting point. The closer the incident angle of the measuring light is to the Brewster angle, the more the temperature matching of the temperature measuring device 100 can be improved. Therefore, in the case where the measuring light can be irradiated at the optimal incident angle (angle adjacent to the Brewster angle) that maximizes the temperature matching of the temperature measuring device 100, the time-reflectivity curve output by the temperature relationship derivation method according to an embodiment of the present invention can include three inflection points in the maximum value region or the minimum value region. The reflectivity-temperature relationship derived by the above method and value is shown in Mathematical Formula 1.

[0078]

Mathematical formula 1

[0079]

[0080] Here, TRT is the absolute temperature at room temperature, ΔTm.p. is the temperature change from room temperature to melting point, and ΔVm.p. is the reflectivity change from room temperature to melting point. ΔV can be substituted into the polarization reflectivity of the target material T calculated from the detection value of the detection component to derive the surface temperature of the target material.

[0081] The processing unit 400 may determine the surface temperature of the target substance T by applying the polarization reflectivity of the target substance T to a linear temperature relationship obtained from the normal temperature polarization reflectivity of the target substance T and the melting point polarization reflectivity of the target substance T.

[0082] On the other hand, the processing unit 400 may include an output device for outputting the determined surface temperature of the target substance T as a graph over time. As an example, the processing unit 400 may include a high-speed signal processing device such as an oscilloscope.

[0083] In one embodiment, the processing unit 400 includes any processor or device that executes a series of software commands or the same, including but not limited to a general or special microprocessor, a finite state machine, a controller, a computer, a central processing unit (CPU), an FPGA (field-programmable gate array) or a digital signal processor. In one embodiment, the processor can be an Intel XEON or PENTIUM processor or an AMD TURION or other processors manufactured by AMD, Intel or other semiconductor processor manufacturers.

[0084] The processing unit 400 is operably connected to a memory (not shown). In this specification, the term "memory" refers to any processor-readable medium including RAM, ROM, EPROM, PROM, EEPROM, disk, floppy disk, hard disk, CD-ROM, DVD, etc., which stores a series of commands that can be executed by the processing unit 400, and is not limited to the above-mentioned cases.

[0085] Figure 7 FIG. 1 is a flow chart schematically showing a temperature measurement method according to an embodiment of the present invention. Figure 7 According to an embodiment of the present invention, the temperature measurement method may include a temperature relationship calculation and storage step S50, a light irradiation step S100, a light detection step S200, and a calculation step S300. Figure 7 The temperature measurement method is applied in Figure 1 The surface temperature of the target material T is measured by the temperature measuring device shown.

[0086] The temperature relationship equation calculation and storage step S50 is a step performed before measuring the surface temperature of the target material, and is a step of calculating the temperature relationship equation based on the reflectivity of the material to be measured, and storing the calculated relationship equation in the processing unit 400. The temperature relationship equation calculation and storage step S50 can be performed by Figure 1 The temperature measurement device 100 shown executes the method identical to or substantially similar to the temperature relationship equation derivation method described above, and thus the description thereof is omitted.

[0087] The light irradiation step S100 is a step of irradiating a measurement light for measuring a temperature change of the target substance T to a point of the target substance T. At this time, the measurement light may be incident on the surface of the target substance T at an oblique angle.

[0088] As an example, the measuring light may be a continuous beam irradiated from a CW laser. The measuring light may be incident obliquely on the surface of the target material T through the optical system 200 that forms a light path toward the target material T. In this case, the measuring light may be incident at an angle that is maximally adjacent to the Brewster angle, thereby deriving a highly accurate measurement value.

[0089] The light detection step S200, as a step of detecting the intensity of the measurement light, may include a process of detecting the intensity of the incident light incident on the target substance T and the intensity of the reflected light reflected from the target substance T. The light detection step S200 may be performed by a detection component such as a photodiode or the like. The intensity of the incident light may be a specified value as a set value. According to an embodiment of the present invention, the intensity of the reflected light is detected by separating into p-polarized reflected light and s-polarized reflected light.

[0090] The calculation step S300 is a step of calculating the surface temperature of the target substance T using the value detected in the light detection step S200. In the calculation step S300, the detected value of the target substance T may be selectively applied in p-polarized reflected light and s-polarized reflected light according to the material of the target substance T.

[0091] The calculation step S300 may include a first calculation step S310 of calculating a polarization reflectance of the target substance T and a second calculation step S320 of calculating a surface temperature of the target substance T based on the polarization reflectance.

[0092] The first calculation step S310 can be simply performed using the detection value of the light detection step S200. The reflectivity is a value of the intensity of the reflected light divided by the intensity of the incident light. Therefore, the first calculation step S310 can be a step of dividing the detection value of one of the p-polarized reflected light and the s-polarized reflected light by the detection value of the incident light. The first calculation step S310 can be performed by the processing unit 400.

[0093] The second calculation step S320 is a step of calculating the surface temperature of the target material T using the polarization reflectance calculated in the first calculation step S310 , and the temperature relationship equation shown in Math. 1 derived in S50 and stored in the processing unit 400 may be applied.

[0094] Therefore, the second calculation step S320 may include a step of substituting the polarization reflectivity calculated in the first calculation step S310 into a linear temperature relationship derived using the room temperature reflectivity of the target substance T, the melting point reflectivity of the target substance T, the temperature value of the room temperature, and the melting point temperature value of the target substance. The first calculation step S310 and the second calculation step S32 may be performed by the processing unit 400. As an example, the processing unit 400 includes any processor or device that executes a series of software commands or the same, and is not limited to, executed by a general or special microprocessor, a finite state machine, a controller, a computer, a central processing unit (CPU), an FPGA (field-programmable gate array) or a digital signal processor.

[0095] On the other hand, the temperature measurement method according to the embodiment of the present invention may further include an outputting step S400 of outputting the surface temperature data of the target substance T.

[0096] As described above, through the present invention, the surface temperature of the target material is calculated based on the polarization reflectivity recovered from the surface of the target material and applied to the high-speed signal processing device, so that the surface temperature of the target material of the high-speed heat treatment can be monitored in real time. In particular, by using the polarization reflectivity, the measurement result with improved accuracy can be confirmed.

[0097] The present invention is described above, but the present invention is not limited by the disclosed embodiments and the attached drawings, and ordinary technicians can make various modifications within the scope of the technical concept of the present invention. In addition, the technical concept described in the embodiments of the present invention can also be implemented independently, or two or more can be implemented in combination with each other.

Claims

1. A temperature measuring device, include: A measuring light source irradiates a point on the surface of a target material with measuring light in order to measure the surface temperature of the target material; an optical system forming a light path of the measuring light toward a surface of the target material; A plurality of detection components for detecting the incident light and reflected light intensity of the measurement light; as well as The processing unit calculates a reflectivity of the target substance based on the detection value of each of the plurality of detection components, and determines a surface temperature of the target substance based on the reflectivity.

2. The temperature measuring device according to claim 1, in, The optical system includes a polarization separator that separates the reflected light into p-polarized reflected light and s-polarized reflected light.

3. The temperature measuring device according to claim 2, in, The plurality of detection components include: A first detection component, outputting the intensity of the incident light; A second detection component, outputting the intensity of the p-polarized reflected light; and The third detection component outputs the intensity of the s-polarized reflected light.

4. The temperature measuring device according to claim 3, in, The processing unit calculates a polarization reflectance of the target substance based on the detection value of each of the plurality of detection elements.

5. The temperature measuring device according to claim 4, in, The processing unit applies the polarization reflectivity of the target material to a stored temperature relationship to determine the surface temperature of the target material.

6. The temperature measuring device according to claim 5, in, The temperature relationship equation is a linear relationship equation derived from the polarization reflectance of the target substance at room temperature and the polarization reflectance of the target substance at the melting point of the target substance.

7. The temperature measuring device according to claim 6, in, The temperature relationship equation can be derived by irradiating the surface of the target substance with heating light that can rapidly change the temperature of the surface of the target substance to the melting point of the target substance together with the measurement light.

8. The temperature measuring device according to claim 1, in, The temperature measurement device further includes: an output device for outputting the surface temperature change of the target substance generated over time.

9. A method for deriving a temperature relationship. include: a light irradiation step of irradiating a heating light for heating a target substance and a measuring light for detecting a change in reflectivity of the target substance caused by the heating light to the same point of the target substance; A light detection step, detecting the incident light and reflected light intensity of the measurement light; as well as a calculation step of deriving a temperature relationship equation based on the reflectivity of the target substance using the value detected in the light detection step, The heating light is a pulse beam that rapidly changes the temperature of the surface of the target substance to the melting point of the target substance.

10. The method for deriving a temperature relationship equation according to claim 9, in, The light detection step separates the reflected light into p-polarization and s-polarization to detect the intensity of the reflected light.

11. The method for deriving a temperature relationship equation according to claim 10, in, The calculating step uses a value detected from at least one of p-polarization and s-polarization of the reflected light according to a material kind of the target material surface.

12. The method for deriving a temperature relationship equation according to claim 11, in, The calculation steps include: A first calculation step is to calculate the polarization reflectivity of the target material; and The second calculation step is to derive a temperature relationship equation of the target substance based on the polarization reflectivity.

13. The method for deriving a temperature relationship equation according to claim 12, in, The second calculation step derives a linear temperature relationship from the polarization reflectance when the target substance is at room temperature and the polarization reflectance when the surface temperature of the target substance reaches a melting point.

14. The method for deriving a temperature relationship equation according to claim 13, in, The graph showing the p-polarized reflectance of the target substance over time includes three inflection points in a maximum value region or a minimum value region according to at least one of the kind of the target substance and the incident angle of the measurement light.

15. The method for deriving a temperature relationship equation according to claim 14, in, In the case where the three inflection points are included in the maximum value region of the graph, the polarization reflectance when the surface temperature of the target substance reaches the melting point is the maximum value of the graph.

16. The method for deriving a temperature relationship equation according to claim 14, in, In the case where the three inflection points are included in the minimum value region of the graph, the polarization reflectance when the surface temperature of the target substance reaches the melting point is the minimum value of the graph.

17. A method for measuring temperature, include: The step of calculating and storing a temperature relationship based on the reflectivity of the target material; a light irradiation step of obliquely incident a measurement light for measuring the surface temperature of the target substance on a point of the target substance; A light detection step of detecting the incident light and reflected light intensities of the measurement light obliquely incident on the target substance; as well as a calculation step of calculating the surface temperature of the target substance by applying the value detected in the light detection step to the temperature relationship equation, The light detection step separates the reflected light into p-polarization and s-polarization to detect the intensity of the reflected light.

18. The temperature measurement method according to claim 17, in, The temperature relationship equation is a linear relationship equation derived from the polarization reflectance of the target substance at room temperature and the polarization reflectance of the target substance at the melting point of the target substance.

19. The temperature measurement method according to claim 18, in, The calculating step uses a value detected from at least one of p-polarization and s-polarization of the reflected light according to a material type of the surface of the target material, The calculation steps include: A first calculation step is to calculate the polarization reflectivity of the target material; and The second calculation step is to apply the polarization reflectance calculated in the first calculation step to the temperature relationship to calculate the surface temperature of the target material.

20. The temperature measurement method according to claim 17, in, The temperature measurement method further includes: an output step of outputting the surface temperature change of the target substance generated over time.

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