Non-contact temperature measuring device and non-contact temperature measuring method

Abstract

It includes: a light emitting unit (light source (18a)) that emits measurement light (L1) toward the surface (Wa); a light receiving unit (light receiving sensor (18b)) that receives the reflected light (L2A) of the measurement light (L1) reflected on the surface (Wa) and the reflected light (L2B) of the measurement light (L1) reflected on the back side (Wb) of the object to be measured opposite to the surface (Wa), and outputs a light receiving signal; and a thickness calculation unit (18c) that sets the actual thickness of the object to be measured as a first thickness (thickness (L1)). v The thickness obtained by multiplying the first thickness by the refractive index of the object being measured is set as the second thickness (thickness (L)). opt In the case of )), the second thickness is calculated based on the light received signal output from the light receiving unit; the measured object information acquisition unit (wafer information acquisition unit (34)) acquires the measured object information (wafer information (29)); and the temperature calculation unit (36) calculates the temperature of the measured object based on the second thickness and the measured object information.

Description

Technical Field

[0001] This invention relates to a non-contact temperature measuring device and a non-contact temperature measuring method for measuring the temperature of a translucent object in a non-contact manner. Background Technology

[0002] In semiconductor manufacturing processes that produce wafers of silicon (Si), silicon carbide (SiC), and gallium nitride (GaN), in order to improve wafer quality and yield, it is required to accurately measure and control various parameters in the semiconductor manufacturing process, especially the temperature of the wafer (see Patent Documents 1 and 2, Non-Patent Documents 1 and 2).

[0003] Methods for measuring the temperature of a wafer (the object being measured) include, for example, methods using electronic thermometers (thermocouples, thermistors, and platinum resistance thermometers, etc.), methods using radiation thermometers, and methods using fluorescent fiber optic thermometers.

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 2018-073962

[0007] Patent Document 2: Japanese Patent Application Publication No. 2020-077864

[0008] Non-patent literature

[0009] Non-Patent Document 1: Kenji Ishikawa, 1 other, "The forefront of ultra-dry etching technology for realizing advanced device construction", [online], J. Plasma Fusion Res. Vol.97, No.9 (2021) 508-510, [accessed December 27, 2016], Internet <URL:https: / / www.jspf.or.jp / Journal / PDF_JSPF / jspf2021_09 / 9709SPall.pdf>

[0010] Non-Patent Literature 2: Toru Iuchi, “In-situ Temperature Measurement of Silicon Semiconductor Wafers”, [online], Measurement & Control, Vol. 47, No. 5, May 2008, [retrieved on December 27, 2008], Internet <URL: https: / / www.jstage.jst.go.jp / article / sicejl / 47 / 5 / 47_395 / _pdf> Summary of the Invention

[0011] The problem that the invention aims to solve

[0012] However, when using electronic thermometers to measure the temperature of wafers, the thermometer needs to be in contact with the wafer, thus increasing the workload for the operator. Furthermore, there is a risk that the measurement error of the electronic thermometer may increase due to electromagnetic interference from the thermometer's leads, high magnetic fields, or high voltage.

[0013] When using a radiation thermometer to measure the temperature of a wafer, there is a problem that the temperature measurement results may be incorrect when there is a source that generates infrared radiation, such as plasma, around the wafer.

[0014] Fluorescent fiber optic thermometers are highly resistant to electrical, magnetic, and mechanical noise, but require the phosphor to be in contact with the crystal. Therefore, temperature measurements performed using fluorescent fiber optic thermometers cannot be considered completely non-contact, increasing the workload for operators.

[0015] The present invention was made in view of this situation, and its purpose is to provide a non-contact temperature measuring device and a non-contact temperature measuring method that can perform temperature measurement of the measured object simply and with high accuracy.

[0016] Methods for solving problems

[0017] A non-contact temperature measuring device for achieving the purpose of the present invention measures the temperature of a test object having light transmittance on a surface and a back surface in a non-contact manner. The non-contact temperature measuring device comprises: a light emitting unit that emits measuring light toward the surface; a light receiving unit that receives reflected light from the measuring light reflected on the surface and reflected light from the measuring light reflected from the back surface of the test object on the opposite side of the surface, passing through the interior of the test object, and outputs a light receiving signal; a thickness calculation unit that calculates a second thickness based on the light receiving signal output from the light receiving unit, wherein the actual thickness of the test object is set as a first thickness and the thickness obtained by multiplying the first thickness by the refractive index of the test object is set as a second thickness; a test object information acquisition unit that acquires test object information including the first thickness, refractive index, and the temperature coefficient of refractive index of the test object; and a temperature calculation unit that calculates the temperature of the test object based on the second thickness calculated by the thickness calculation unit and the test object information acquired by the test object information acquisition unit.

[0018] According to this non-contact temperature measuring device, the temperature of the object being measured can be measured non-contactly based on the measurement results obtained by non-contact measurement of the second thickness of the object being measured.

[0019] In another aspect of the non-contact temperature measuring device of the present invention, the measured object information acquisition unit acquires measured object information including a first thickness, refractive index, temperature coefficient of refractive index, and coefficient of linear thermal expansion of the measured object. Therefore, the temperature of the measured object can be measured non-contactly based on the measurement result obtained by non-contactly measuring a second thickness of the measured object.

[0020] In another aspect of the non-contact temperature measuring device of the present invention, the light emitting unit emits measuring light of multiple wavelengths toward the surface, and the light receiving unit receives reflected light for each wavelength and outputs a light receiving signal.

[0021] The thickness calculation unit calculates the second thickness for each wavelength based on the light received signal output from the light receiving unit. The temperature calculation unit calculates the temperature of the measured object based on the second thickness for each wavelength calculated by the thickness calculation unit and the measured object information.

[0022] A non-contact temperature measuring device for achieving the purpose of the present invention measures the temperature of a test object having light transmittance on a surface and a back surface in a non-contact manner. The non-contact temperature measuring device includes: a light emitting unit that emits measuring light toward the surface; a light receiving unit that receives reflected light from the measuring light reflected on the surface and reflected light from the measuring light reflected from the back surface of the test object on the opposite side of the surface, passing through the interior of the test object, and outputs a light receiving signal; a thickness calculation unit that calculates the second thickness based on the light receiving signal output from the light receiving unit, taking the actual thickness of the test object as a first thickness and the thickness obtained by multiplying the first thickness by the refractive index of the test object as a second thickness; a correlation data acquisition unit that acquires in advance correlation data showing the correlation between the second thickness and the temperature of the test object; and a temperature calculation unit that calculates the temperature of the test object based on the second thickness calculated by the thickness calculation unit and referring to the correlation data acquired by the correlation data acquisition unit.

[0023] According to this non-contact temperature measuring device, the temperature of the object being measured can be measured non-contactly based on the measurement results obtained by non-contact measurement of the second thickness of the object being measured.

[0024] The non-contact temperature measurement method for achieving the purpose of this invention measures the temperature of a test object having light transmittance on a surface and a back surface in a non-contact manner. The non-contact temperature measurement method includes: a light emission step, emitting measurement light toward the surface; a light receiving step, receiving reflected light from the surface and reflected light from the back surface of the test object, which is reflected from the interior of the test object on the opposite side of the surface, and outputting a light receiving signal; a thickness calculation step, calculating the second thickness based on the light receiving signal, where the actual thickness of the test object is set as a first thickness and the thickness obtained by multiplying the first thickness by the refractive index of the test object is set as a second thickness; a test object information acquisition step, acquiring test object information including the first thickness, refractive index, and the temperature coefficient of refractive index of the test object; and a temperature calculation step, calculating the temperature of the test object based on the second thickness calculated in the thickness calculation step and the test object information acquired in the test object information acquisition step.

[0025] The non-contact temperature measurement method for achieving the objectives of this invention measures the temperature of a test object having light transmittance on both a surface and a back surface in a non-contact manner. The non-contact temperature measurement method includes: a light emission step, emitting measurement light toward the surface; a light receiving step, receiving reflected light from the surface and reflected light from the back surface of the test object, which is reflected from the interior of the test object on the opposite side of the surface, and outputting a light receiving signal; a thickness calculation step, calculating the second thickness based on the light receiving signal, where the actual thickness of the test object is set as a first thickness and the thickness obtained by multiplying the first thickness by the refractive index of the test object is set as a second thickness; a correlation data acquisition step, acquiring relevant data showing the correlation between the second thickness and the temperature of the test object in advance; and a temperature calculation step, calculating the temperature of the test object based on the second thickness calculated in the thickness calculation step and referring to the relevant data acquired in the correlation data acquisition step.

[0026] Invention Effects

[0027] This invention enables simple and highly accurate temperature measurement of the object being measured. Attached Figure Description

[0028] Figure 1 This is a schematic diagram of the non-contact temperature measuring device according to the first embodiment.

[0029] Figure 2 This is an explanatory diagram used to illustrate the measuring light emitted from the sensor head and the reflected light incident on the sensor head.

[0030] Figure 3 This is a functional block diagram of the control device in the first embodiment.

[0031] Figure 4 This shows the thickness L when the wafer is made of silicon. opt A graph showing the relationship between temperature change ΔT and temperature.

[0032] Figure 5 It is shown Figure 4 The diagram with reference 4A in the attached figure and Figure 4 The graph labeled 4B in the attached figure shows the error of the graph.

[0033] Figure 6 This is a flowchart illustrating the process of a non-contact temperature measurement method for a wafer performed by the non-contact temperature measuring apparatus of the first embodiment.

[0034] Figure 7 This is a schematic diagram of the non-contact temperature measuring device according to the second embodiment.

[0035] Figure 8 This is a functional block diagram of the control device in the second embodiment.

[0036] Figure 9 This is a schematic diagram of the non-contact temperature measuring device according to the third embodiment.

[0037] Figure 10 This is an illustrative diagram used to explain an example of how relevant data is generated.

[0038] Figure 11 This is a diagram illustrating an example of the recorded data from a data logger.

[0039] Figure 12 This is a graph showing an example of relevant data.

[0040] Figure 13 This is a flowchart illustrating the process of a non-contact temperature measurement method for a wafer performed by the non-contact temperature measuring apparatus of the third embodiment. Detailed Implementation

[0041] [First Implementation]

[0042] Figure 1 This is a schematic diagram of the non-contact temperature measuring device 10 according to the first embodiment of the present invention. The non-contact temperature measuring device 10 is used in semiconductor manufacturing processes for producing various wafers W, such as silicon, and performs non-contact measurement of the wafer temperature, which is the temperature of the wafer W. The wafer W corresponds to the object to be measured in the present invention and is transparent. For example, when the wafer W is a silicon wafer, it is substantially transparent to light with wavelengths from 1.2 μm to 6 μm.

[0043] The non-contact temperature measuring device 10 includes a thickness measuring device 12 and a computer 20. It should be noted that the functions of the computer 20, described later, can also be implemented in the thickness measuring device 12 (thickness measuring device body 18). In this case, the thickness measuring device 12 also functions as a standalone unit of the non-contact temperature measuring device 10.

[0044] The thickness measuring device 12 performs non-contact measurement of the thickness of the wafer W using an optical method. Examples of such a thickness measuring device 12 include, for example, a wavelength scanning laser interferometer, an interferometer using beam splitting interferometry (SS-OCT: Swept Source Optical Coherence Tomography), or an interferometer using vertical scanning low coherence interferometry (CSI: Coherence Scanning Interferometry, TD (Time-domain)-OCT), etc.

[0045] The thickness measuring device 12 includes, for example, a sensor head 14, an optical fiber cable 16, and a thickness measuring device body 18. It should be noted that the structure of the thickness measuring device 12 can be appropriately modified as long as it can perform non-contact measurement of the thickness of the wafer W in an optical manner.

[0046] Figure 2 This is an explanatory diagram illustrating the measuring light L1 emitted from the sensor head 14 and the reflected light L2 incident on the sensor head 14. (See diagram for example.) Figure 2 and the above Figure 1 As shown, the sensor head 14 corresponds to the light emitting section of the present invention and is positioned opposite the surface Wa of the wafer W. Here, surface Wa is the opposing surface opposite to the sensor head 14 and is the incident surface for the measurement light L1 from the sensor head 14 to be incident upon. In addition, the back surface Wb of the wafer W is the side opposite to the surface Wa of the wafer W.

[0047] The sensor head 14 is optically connected to the thickness measuring device body 18 via an optical fiber cable 16, and emits the measuring light L1 incident from the thickness measuring device body 18 toward the surface Wa. It should be noted that the measuring light L1 is light of wavelength (wavelength region) that passes through the chip W.

[0048] A portion of the measurement light L1 incident from sensor head 14 onto surface Wa is reflected as reflected light L2A from surface Wa toward sensor head 14, while the remaining portion passes through the interior of wafer W to reach the back surface Wb of wafer W. For example, wafer W is a silicon wafer with a refractive index of 3.483 (wavelength of measurement light L1: 1.5 μm) and a temperature coefficient of 1.8 × 10⁻⁶. -4 In the case of [ ], 27% of the measured light L1 becomes the reflected light L2A.

[0049] A portion of the measuring light L1 reaching the back surface Wb is reflected as reflected light L2B from the back surface Wb toward the surface Wa, while the remainder is emitted from the back surface Wb toward the outside of the wafer W. Furthermore, a portion of the reflected light L2B that is reflected toward the surface Wa is emitted from the surface Wa toward the sensor head 14, while the remainder is again reflected from the surface Wa toward the back surface Wb.

[0050] It should be noted that, when the wafer W is the silicon wafer described above, the measurement light L1 emitted from the back surface Wb to the outside of the wafer W is 53% of the original measurement light L1, and the reflected light L2B emitted from the surface Wa toward the sensor head 14 is 14% of the original measurement light L1.

[0051] The reflected light L2, including the reflected light L2A reflected on the surface Wa and the reflected light L2B reflected on the back surface Wb, is incident on the sensor head 14. The reflected light L2 incident on the sensor head 14 is then incident on the thickness measuring device body 18 via the fiber optic cable 16.

[0052] return Figure 1 The thickness measuring device body 18 includes a light source 18a, a light sensor 18b, and a thickness calculation unit 18c.

[0053] Light source 18a emits measurement light L1 into fiber optic cable 16. Thus, measurement light L1 is incident on sensor head 14 via fiber optic cable 16, and emitted from sensor head 14 towards surface Wa. Additionally, light-receiving sensor 18b, corresponding to the light-receiving part of this invention, receives reflected light L2 incident from sensor head 14 via fiber optic cable 16 and outputs a light-receiving signal. It should be noted that light source 18a and light-receiving sensor 18b can also be disposed on sensor head 14.

[0054] The thickness calculation unit 18c calculates the thickness L of the wafer W based on the light-receiving signal output from the light-receiving sensor 18b. opt (equivalent to the second thickness of the present invention), and the thickness L opt The calculation results are output to computer 20. It should be noted that the thickness L of the wavelength scanning laser interferometer, the interferometer using beam splitting interferometry, and the interferometer using vertical scanning low-coherence interferometry... opt The calculation method is well-known, so a detailed explanation is omitted here. Additionally, the thickness L of the wafer W calculated by the thickness calculation unit 18c... opt This becomes the actual thickness L of the wafer W. v The thickness obtained by multiplying the refractive index of wafer W (corresponding to the first thickness of this invention) is therefore different from the actual thickness L. v different.

[0055] It should be noted that the thickness calculation unit 18c can also be provided in the control device 22 of the computer 20 described later (see reference). Figure 3 In this case, the light sensor 18b outputs the light signal received by the reflected light L2 to the control device 22.

[0056] The computer 20 includes a control unit 22, an operation unit 24, and a display unit 26. It should be noted that various known arithmetic devices may also be used instead of the computer 20.

[0057] Control device 22 performs thickness measurement of wafer W by thickness measuring device 12 (measuring the emission of light L1, the reception of reflected light L2, and the thickness L). opt The control device 22 is equipped with a thickness measuring instrument body 18, an operation unit 24, and a display unit 26.

[0058] The operation unit 24 accepts various operations from the non-contact temperature measuring device 10, such as starting the temperature measurement of the chip W. The operation unit 24 includes various operating devices such as a mouse, keyboard, and operation buttons.

[0059] The display unit 26 uses, for example, an LCD display, and displays various settings screens of the non-contact temperature measuring device 10, as well as the measurement results of the chip temperature.

[0060] Figure 3 This is a functional block diagram of the control device 22 in the first embodiment. (For example...) Figure 3 As shown, the control device 22 includes arithmetic circuits composed of various processors and memory. These processors include CPUs (Central Processing Units), GPUs (Graphics Processing Units), ASICs (Application Specific Integrated Circuits), and programmable logic devices (such as SPLDs (Simple Programmable Logic Devices), CPLDs (Complex Programmable Logic Devices), and FPGAs (Field Programmable Gate Arrays)). It should be noted that the various functions of the control device 22 can be implemented by a single processor or by multiple processors of the same or different types.

[0061] In addition to the thickness measuring device body 18, operation unit 24, and display unit 26 described above, the control device 22 also includes a storage unit 28. It should be noted that the storage unit 28 can also be built into the control device 22. In addition to the control program (not shown) of the control device 22, the storage unit 28 also stores wafer information 29, corresponding to the measured object information of the present invention, for each type of wafer W.

[0062] The wafer information 29 contains information related to the actual size, properties, and characteristics of the material (such as silicon) of the wafer W, and is used in the wafer temperature calculation performed by the control device 22 (temperature calculation unit 36) described later. Specifically, the wafer information 29 includes the actual thickness L of the wafer W, measured by a method different from that using the thickness measuring device 12. v The refractive index n and the temperature coefficient of refractive index Δn of the known wafer W are... t And the coefficient of linear thermal expansion α.

[0063] The control device 22 functions as a measurement control unit 30, a thickness acquisition unit 32, a wafer information acquisition unit 34, and a temperature calculation unit 36 ​​by executing a control program (not shown) stored in the storage unit 28.

[0064] The measurement control unit 30 operates in response to the input of the temperature measurement start operation of the operation unit 24, and performs the thickness measurement of the wafer W by the thickness measuring device 12. Specifically, the measurement control unit 30 performs the emission of measurement light L1 from the light source 18a, the reception of reflected light L2 by the light sensor 18b and the output of the light signal, and the thickness L2 measurement by the thickness calculation unit 18c. opt The operation.

[0065] The thickness acquisition unit 32 performs the thickness L calculation in the thickness calculation unit 18c. opt In the case of calculation, the thickness L is obtained from the thickness calculation unit 18c. opt The calculation result is obtained and output to the temperature calculation unit 36.

[0066] The chip information acquisition unit 34 corresponds to the measured object information acquisition unit of the present invention. This chip information acquisition unit 34 operates in response to inputs such as temperature measurement start operation, acquiring chip information 29 from the storage unit 28 and outputting the chip information 29 to the temperature calculation unit 36. It should be noted that, instead of acquiring the chip information 29 from the storage unit 28, the chip information acquisition unit 34 may also acquire the chip information 29 from an external server via a known communication network.

[0067] Temperature calculation unit 36 ​​calculates the temperature based on the thickness L input from thickness acquisition unit 32. optThe wafer temperature is calculated using wafer information 29 input from the wafer information acquisition unit 34. Hereinafter, a specific example of the wafer temperature calculation performed by the temperature calculation unit 36 ​​will be described.

[0068] As described above, the thickness L of wafer W opt It is the actual thickness L v The thickness is obtained by multiplying the refractive index n of the wafer W. Therefore, the actual thickness L v It is represented by the following [Mathematical Formula 1].

[0069] [Mathematical Expression 1]

[0070]

[0071] Here, the refractive index n exhibits a temperature dependence, which is known as the "temperature coefficient of refractive index Δn". t "In addition, the actual thickness L..." v There is also a temperature dependence, which is known as the "linear thermal expansion coefficient α". Therefore, when the temperature change of the wafer W from the specified reference temperature T is set as ΔT, the above [Mathematical Formula 1] is expressed as [Mathematical Formula 2] below.

[0072] [Mathematical Expression 2]

[0073]

[0074] In the above [Mathematical Equation 2], the refractive index n and the temperature coefficient of refractive index Δn at the reference temperature T are... t This is a parameter related to the material of wafer W, and therefore a known value. Additionally, the coefficient of linear thermal expansion α is also a parameter related to the material of wafer W, and therefore a known value. Therefore, by obtaining the aforementioned wafer information 29 (actual thickness L) beforehand... v Refractive index n, temperature coefficient of refractive index Δn t And the coefficient of linear thermal expansion α), thus enabling the calculation based on thickness L. opt And the chip information 29, as shown in [Mathematical Formula 3] below, derives the temperature change ΔT. Furthermore, the chip temperature can be calculated based on the derived temperature change ΔT and the known reference temperature T.

[0075] [Mathematical Expression 3]

[0076]

[0077] Temperature calculation unit 36 ​​calculates the temperature based on the thickness L input from thickness acquisition unit 32. optThe wafer information 29 input from the wafer information acquisition unit 34 is used to calculate the temperature change ΔT using the above-mentioned [Mathematical Formula 3], and the wafer temperature is calculated based on the temperature change ΔT and the known reference temperature T.

[0078] It should be noted that in the above [Mathematical Equation 3], the temperature coefficient of refractive index Δn t It is approximately 100 times the linear thermal expansion coefficient α. Therefore, the linear thermal expansion coefficient α can be simplified to α = 0.0 based on the required accuracy of the wafer temperature. In this case, the above [Mathematical Equation 3] is simplified as shown in [Mathematical Equation 4] below.

[0079] [Mathematical Expression 4]

[0080]

[0081] Figure 4 This indicates that the wafer W is made of silicon (refractive index n = 3.4, refractive index temperature coefficient Δn). t =2.0×10 -4 and the actual thickness L v Thickness L in the case of (=0.777mm) opt A graph showing the relationship between temperature change ΔT and temperature. It should be noted that... Figure 4 The graph in Figure 4A shows the linear thermal expansion coefficient α set as "α = 2.6 × 10⁻⁶". -6 Thickness L under the condition of " opt The relationship with temperature change ΔT. Additionally... Figure 4 The graph in Figure 4B shows the thickness L when the linear thermal expansion coefficient α is simplified to "α = 0.0". opt Relationship with temperature change ΔT.

[0082] Figure 5 It is shown Figure 4 The diagram with reference 4A in the attached figure and Figure 4 The graph labeled 4B in the attached figure shows the error of the graph.

[0083] like Figure 4 as well as Figure 5 As shown, it was confirmed that the error between simplifying the linear thermal expansion coefficient α to "α = 0.0" and not simplifying it is minimal. Therefore, there is no problem even if the linear thermal expansion coefficient α is simplified according to the required accuracy of the wafer temperature. In this case, the calculation of the temperature change ΔT performed by the temperature calculation unit 36 ​​is simplified, and therefore the time required for the wafer temperature calculation is reduced.

[0084] [Function of the non-contact temperature measuring device in the first embodiment]

[0085] Figure 6This is a flowchart illustrating the process of non-contact temperature measurement of wafer W performed by the non-contact temperature measuring apparatus 10 of the first embodiment. It should be noted that the wafer information 29 is assumed to be wafer information pre-stored in the storage unit 28.

[0086] like Figure 6 As shown, when the operation unit 24 inputs the start of temperature measurement operation (step S1), the control device 22 functions as the measurement control unit 30, the thickness acquisition unit 32, the wafer information acquisition unit 34, and the temperature calculation unit 36. Then, the measurement control unit 30 performs the thickness measurement of the wafer W by the thickness measuring device 12. As a result, the measurement light L1 is emitted from the light source 18a and emitted from the sensor head 14 toward the surface Wa of the wafer W via the optical fiber cable 16 (step S2, corresponding to the light emission step of the present invention).

[0087] When the measuring light L1 is emitted from the sensor head 14 toward the surface Wa, the reflected light L2, including the reflected light L2A reflected on the surface Wa and the reflected light L2B reflected on the back surface Wb, is incident on the sensor head 14. The reflected light L2 incident on the sensor head 14 is then incident on the light receiving sensor 18b via the optical fiber cable 16. Thus, the light receiving sensor 18b receives the reflected light L2 and outputs the light receiving signal (step S3, corresponding to the light receiving step of the present invention).

[0088] Next, the thickness calculation unit 18c calculates the thickness L of the wafer W based on the light-receiving signal output from the light-receiving sensor 18b. opt The calculation result is then output to the temperature calculation unit 36 ​​(step S4, equivalent to the thickness calculation step of this invention). Thus, the thickness L of the wafer W is... opt Non-contact measurement.

[0089] On the other hand, the wafer information acquisition unit 34 acquires wafer information 29 from the storage unit 28 in response to the input of the temperature measurement start operation of the operation unit 24, and outputs the wafer information 29 to the temperature calculation unit 36 ​​(step S5, which corresponds to the measured object information acquisition step of the present invention). It should be noted that the timing of the acquisition of wafer information 29 by the wafer information acquisition unit 34 is not particularly limited as long as it is before the calculation of the wafer temperature by the temperature calculation unit 36.

[0090] Then, the temperature calculation unit 36 ​​calculates the thickness L input from the thickness calculation unit 18c. opt The wafer information 29 input from the wafer information acquisition unit 34 is used to calculate the temperature change ΔT using the above-mentioned [mathematical formula 3] or [mathematical formula 4], and the wafer temperature is calculated based on the temperature change ΔT and the reference temperature T (step S6, which is equivalent to the temperature calculation step of the present invention).

[0091] As described above, the non-contact temperature measuring device 10 of the first embodiment measures the temperature solely by measuring the thickness L of the wafer W. opt Non-contact measurement allows for the determination of wafer temperature, thus avoiding the influence of electrical, magnetic, and mechanical noise, as well as infrared-emitting plasma, enabling non-contact temperature measurement of wafer W. As a result, temperature measurement of wafer W can be performed simply and with high accuracy.

[0092] [Second Implementation]

[0093] Figure 7 This is a schematic diagram of the non-contact temperature measuring device 10 according to the second embodiment. Figure 8 This is a functional block diagram of the control device 22 in the second embodiment. The non-contact temperature measuring device 10 of the first embodiment uses a single-wavelength measuring light L1 to perform non-contact temperature measurement of the wafer. However, in semiconductor manufacturing processes, the actual thickness L of the wafer W... v In cases of significant temperature variations, there is a risk of errors in the measured wafer temperature. Therefore, the non-contact temperature measuring device 10 of the second embodiment uses measuring light L1 of multiple wavelengths (here, two wavelengths) to perform non-contact temperature measurement of the wafer.

[0094] like Figure 7 as well as Figure 8 As shown, the non-contact temperature measuring device 10 of the second embodiment has a structure that is basically the same as the non-contact temperature measuring device 10 of the first embodiment, except that it has a thickness measuring device 12A that is different from the thickness measuring device 12 of the first embodiment. Therefore, components that are functionally or structurally the same as those in the first embodiment are labeled with the same reference numerals and their descriptions are omitted.

[0095] The thickness measuring device 12A uses two different wavelengths (wavelength λ1 and wavelength λ2) of measuring light L1 to non-contactly measure the thickness L of the wafer W. opt，λ1 and thickness L opt，λ2 The thickness measuring device 12A, in addition to the aforementioned sensor head 14 and fiber optic cable 16, also includes a fiber optic coupler 17 and thickness measuring device bodies 18-1 and 18-2.

[0096] The fiber optic coupler 17 is, for example, a WDM (Wavelength Division Multiplexing) combiner / splitter. One end of the fiber optic coupler 17 is connected to a fiber optic cable 16 (sensor head 14), and the other end is connected to thickness measuring device bodies 18-1 and 18-2, respectively. The fiber optic coupler 17 combines (combines) the measurement light L1 with wavelength λ1 incident from the thickness measuring device body 18-1 and the measurement light L1 with wavelength λ2 incident from the thickness measuring device body 18-2, and outputs it to the fiber optic cable 16 (sensor head 14). Additionally, the fiber optic coupler 17 splits the two wavelengths of reflected light L2 incident from the fiber optic cable 16, outputting the reflected light L2 with wavelength λ1 to the thickness measuring device body 18-1 and the reflected light L2 with wavelength λ2 to the thickness measuring device body 18-2.

[0097] The thickness measuring device bodies 18-1 and 18-2 have a structure that is basically the same as the thickness measuring device body 18 in the first embodiment.

[0098] The thickness measuring device body 18-1 emits a measuring light L1 with wavelength λ1 from its light source 18a, while the thickness measuring device body 18-2 emits a measuring light L1 with wavelength λ2, which is different from wavelength λ1. These measuring lights L1 with wavelength λ1 and L1 with wavelength λ2 are combined by the fiber optic coupler 17 and then incident on the sensor head 14 via the fiber optic cable 16, exiting from the sensor head 14 towards the surface Wa. Consequently, the reflected light L2 of the two wavelengths (wavelength λ1 and wavelength λ2) is incident on the fiber optic coupler 17 from the sensor head 14 via the fiber optic cable 16 and split into reflected light L2 with wavelength λ1 and reflected light L2 with wavelength λ2. Then, the reflected light L2 with wavelength λ1 exits from the fiber optic coupler 17 towards the thickness measuring device body 18-1, and the reflected light L2 with wavelength λ2 exits from the fiber optic coupler 17 towards the thickness measuring device body 18-2.

[0099] The light sensor 18b of the thickness measuring device body 18-1 receives reflected light L2 of wavelength λ1 incident from the fiber optic coupler 17 and outputs a light signal. The thickness calculation unit 18c of the thickness measuring device body 18-1 calculates the thickness L of the wafer W based on the light signal. opt，λ1 Additionally, the light sensor 18b of the thickness measuring device body 18-2 receives reflected light L2 with wavelength λ2 incident from the fiber optic coupler 17 and outputs a light-receiving signal. The thickness calculation unit 18c of the thickness measuring device body 18-2 calculates the thickness L of the wafer W based on this light-receiving signal. opt，λ2 .

[0100] In the second embodiment, the measurement control unit 30, in response to the input of the temperature measurement start operation to the operation unit 24, causes each of the thickness measuring device bodies 18-1 and 18-2 to perform the following actions: emission of measurement light L1 from the light source 18a, reception of reflected light L2 by the light sensor 18b, output of the light signal, and calculation of thickness L by the thickness calculation unit 18c. opt，λk The calculations are performed for [K=1, 2]. Therefore, the thickness L is calculated for each wavelength of the measured light L1. opt，λk Non-contact measurement is performed.

[0101] In the second embodiment, the thickness acquisition unit 32 acquires the thickness L at the wavelength of each measuring light L1 from the thickness measuring device bodies 18-1 and 18-2. opt，λk The calculation results are obtained and output to the temperature calculation unit 36.

[0102] The temperature calculation unit 36 ​​in the second embodiment calculates the temperature based on the thickness L for each wavelength of the measured light L1. opt，λk The temperature change ΔT is calculated using the wafer information 29 in the same manner as in the first embodiment described above. Furthermore, the temperature calculation unit 36 ​​calculates the wafer temperature based on the temperature change ΔT calculated for the wavelength of each measurement light L1 and the reference temperature T. Hereinafter, an example of the wafer temperature calculation performed by the temperature calculation unit 36 ​​of the second embodiment will be specifically described.

[0103] Let the refractive index n of the crystal W for each wavelength of the measured light L1 be set as refractive index n. λK In the case of [K=1, 2], the thickness L of each wavelength of the measured light L1 opt，λk It is the actual thickness L v Multiply by the refractive index n of the crystal W λK The obtained thickness. Therefore, the actual thickness L v It is represented by the following [Mathematical Formula 5].

[0104] [Mathematical Expression 5]

[0105]

[0106] Then, when the refractive index n λK The temperature dependence is expressed as the temperature coefficient of refractive index Δn t，λK In the case of [K=1, 2], the above [Mathematical Expression 5] is represented by the following [Mathematical Expression 6].

[0107] [Mathematical Expression 6]

[0108]

[0109] When the above [Mathematical Formula 6] is written for each wavelength of the measured light L1, it is represented by the upper and lower parts of the following [Mathematical Formula 7].

[0110] [Mathematical Expression 7]

[0111]

[0112] The left side of the upper part of the above [Mathematical Expression 7] is equal to the left side of the lower part, therefore, the following [Mathematical Expression 8] is obtained from the above [Mathematical Expression 7].

[0113] [Mathematical Expression 8]

[0114]

[0115] Furthermore, when the above [Mathematical Formula 8] is transformed, the temperature change ΔT can be derived as shown in [Mathematical Formula 9] below. Thus, similar to the first embodiment described above, the wafer temperature can be calculated based on the derived temperature change ΔT and the known reference temperature T.

[0116] [Mathematical Expression 9]

[0117]

[0118] It should be noted that the actual thickness L of the wafer W v It can be expressed by three sets of mathematical expressions as shown in [Mathematical Expression 10] below. Therefore, by substituting the temperature change ΔT obtained from [Mathematical Expression 9] above into any one of the three sets of mathematical expressions, the actual thickness L of the wafer W can be obtained. v .

[0119] [Mathematical Expression 10]

[0120]

[0121] The flow of the non-contact temperature measurement method for wafer W performed by the non-contact temperature measuring device 10 of the second embodiment is compared with that described above. Figure 6 The processes described are basically the same, so specific details are omitted here.

[0122] As described above, the non-contact temperature measuring device 10 of the second embodiment is based on the thickness L of a wafer W using measuring light L1 with two wavelengths. opt，λk The wafer temperature is determined using the measurement results and wafer information 29, thereby ensuring that even during the semiconductor manufacturing process, the actual thickness L of the wafer W is measured. v Even under conditions of significant temperature variations, the wafer temperature can be measured with good accuracy.

[0123] It should be noted that in the non-contact temperature measuring device 10 of the second embodiment described above, two wavelength measuring lights L1 are used to measure the wafer temperature, but three or more different wavelength measuring lights L1 can also be used to measure the wafer temperature.

[0124] [Third Implementation]

[0125] Figure 9 This is a schematic diagram of the non-contact temperature measuring device 10 according to the third embodiment. The non-contact temperature measuring devices 10 of the above embodiments are based on the thickness L of the wafer W. opt (thickness L) opt，λK The wafer temperature is calculated using wafer information 29, but sometimes the wafer information 29 (refractive index n, refractive index temperature coefficient Δn) is affected by doping treatment of wafer W. t The coefficient of linear thermal expansion (α) becomes unclear. Therefore, the non-contact temperature measuring device 10 of the third embodiment measures the wafer temperature without using the wafer information 29.

[0126] like Figure 9 As shown, the non-contact temperature measuring device 10 of the third embodiment has a basically the same structure as the first embodiment, except that the related data 29A is stored in the storage unit 28 instead of the wafer information 29, the control device 22 functions as the related data acquisition unit 35 instead of the wafer information acquisition unit 34, and the wafer temperature calculation method of the temperature calculation unit 36 ​​is different. Therefore, the same reference numerals are used for components that are functionally or structurally the same as those in the first embodiment, and their descriptions are omitted.

[0127] Related data 29A shows the thickness L of wafer W. opt Data relating to wafer temperature is stored in advance in storage unit 28 for each type of wafer W.

[0128] Figure 10 This is an illustrative diagram illustrating an example of how the relevant data 29A is generated. For example... Figure 10 As shown, when generating relevant data 29A, a temperature sensor 100 is mounted on the wafer W, and a data logger 102 is connected to the thickness measuring device body 18 and the temperature sensor 100.

[0129] Temperature sensor 100 continuously measures the temperature of wafer W and outputs it continuously to data logger 102. Additionally, thickness measuring unit 18 continuously measures the thickness L of wafer W. opt The thickness L was measured and the thickness L was measured. opt The measurement results are continuously output to the data logger 102.

[0130] Figure 11 This is a diagram illustrating an example of the recorded data stored by data logger 102. For example... Figure 11 As shown, the data logger 102 records the wafer temperature (refer to reference numeral XIA) continuously input from the temperature sensor 100 and the wafer thickness L continuously input from the thickness measuring device body 18 on the same time axis. opt (Refer to reference numeral XIB in the attached drawing). It should be noted that the wafer temperature and thickness L recorded by the data logger 102... opt The records are repeatedly executed near the actual operating temperature.

[0131] Figure 12 This is a graph illustrating an example of relevant data 29A. (As shown...) Figure 12 As shown, the wafer temperature and thickness L recorded by data logger 102 are... opt The recorded data is subjected to a linear approximation (or a polynomial approximation depending on the object being measured) to obtain the thickness L of the wafer W. opt Relevant data 29A (here, the mathematical formula) on the relationship with wafer temperature.

[0132] It should be noted that it can also be used as a substitute. Figure 12 The mathematical formula shown generates a data table as relevant data 29A. Alternatively, the wafer temperature and thickness L recorded by data logger 102 can be used. opt The recorded data is used as teaching data to generate a thickness L opt A machine learning model that takes wafer temperature as input and outputs it, and uses this machine learning model as relevant data 29A.

[0133] return Figure 9 The functions of the measurement control unit 30 and the thickness acquisition unit 32 in the third embodiment are the same as those in the first embodiment, so specific descriptions are omitted here.

[0134] The relevant data acquisition unit 35 operates in response to inputs such as temperature measurement start operation, acquiring relevant data 29A from the storage unit 28 and outputting the relevant data 29A to the temperature calculation unit 36. It should be noted that the relevant data acquisition unit 35 may also acquire the relevant data 29A from an external server via a known communication network instead of acquiring it from the storage unit 28.

[0135] The temperature calculation unit 36 ​​in the third embodiment calculates the temperature based on the thickness L input from the thickness acquisition unit 32. opt The chip temperature is calculated by referring to the relevant data 29A input from the relevant data acquisition unit 35.

[0136] Figure 13This is a flowchart illustrating the process of non-contact temperature measurement of wafer W performed by the non-contact temperature measuring apparatus 10 according to the third embodiment. It should be noted that the related data 29A is assumed to be related data pre-stored in the storage unit 28. Furthermore, the processing of steps S1 to S4 is similar to the above-described utilization... Figure 6 The first embodiment described is the same, so the description is omitted here.

[0137] like Figure 13 As shown, corresponding to the input indicating the start of temperature measurement operation for operation unit 24, the correlation data acquisition unit 35 acquires correlation data 29A from storage unit 28 and outputs the correlation data 29A to temperature calculation unit 36 ​​(step S5A, corresponding to the correlation data acquisition step of the present invention). It should be noted that the timing of the acquisition of correlation data 29A by correlation data acquisition unit 35 is not particularly limited as long as it is before the calculation of wafer temperature by temperature calculation unit 36.

[0138] Next, the temperature calculation unit 36 ​​calculates the temperature based on the thickness L input from the thickness calculation unit 18c. opt The wafer temperature is calculated by referring to the relevant data 29A input from the relevant data acquisition unit 35 (step S6A, corresponding to the temperature calculation step of the present invention). By using the relevant data 29A, the temperature calculation unit 36 ​​can calculate the wafer temperature based on the thickness L. opt The chip temperature is calculated directly.

[0139] As described above, in the non-contact temperature measuring device 10 of the third embodiment, the temperature is measured only by measuring the thickness L of the wafer W. opt By performing non-contact measurement, the wafer temperature can be measured, thus achieving the same effect as the non-contact temperature measuring device 10 described in the first embodiment. Furthermore, in the third embodiment, the wafer temperature can be measured based on the thickness L. opt The wafer temperature is calculated directly, thus it is simpler and takes less time to calculate the wafer temperature compared to the first embodiment described above.

[0140] [other]

[0141] In the above embodiments, the thickness L of the wafer W is... opt (including thickness L) opt，λk Examples of non-contact thickness measuring devices include thickness measuring instruments 12 and 12A (see reference). Figure 1 , Figure 7 However, as long as the thickness L of the wafer W can be measured optically... opt If non-contact measurement is to be performed, the structure of the thickness measuring devices 12 and 12A can be appropriately modified.

[0142] In the above embodiments, the non-contact temperature measuring device 10 for non-contact measurement of the temperature of wafer W has been described as an example, but the present invention can also be applied to the non-contact temperature measuring device 10 for non-contact measurement of the temperature of various objects with light transmittance.

[0143] Explanation of reference numerals in the attached figures

[0144] 10…Non-contact temperature measuring device, 12…Thickness measuring device, 12A…Thickness measuring device, 14…Sensor head, 16…Fiber optic cable, 17…Fiber optic coupler, 18…Thickness measuring device body, 18-1…Thickness measuring device body, 18-2…Thickness measuring device body, 18a…Light source, 18b…Light receiving sensor, 18c…Thickness calculation unit, 20…Computer, 22…Control device, 24…Operating unit, 26…Display unit, 28…Storage unit, 29…Wafer information, 29A…Related data, 30…Measurement control unit, 32…Thickness acquisition unit, 34…Wafer information acquisition unit, 35…Related data acquisition unit, 36…Temperature calculation unit, 100…Temperature sensor, 102…Data logger, L1…Measuring light, L2…Reflected light, L2A…Reflected light, L2B…Reflected light, L… opt …thickness, L v …actual thickness, T…reference temperature, W…wafer, Wa…surface, Wb…backside, n…refractive index, n λK …Refractive index, ΔT…Temperature change, Δn t …temperature coefficient of refractive index, α…coefficient of linear thermal expansion.

Claims

1. A non-contact temperature measuring device, which measures the temperature of a test object having a translucent surface and a back surface in a non-contact manner, wherein, The non-contact temperature measuring device includes: A light emitting section that emits measuring light toward the surface; The light-receiving part receives the reflected light of the measurement light reflected from the surface and the reflected light of the measurement light reflected from the surface through the interior of the object being measured and reflected on the back side of the object being measured on the opposite side of the surface, and outputs a light-receiving signal. The thickness calculation unit calculates the second thickness based on the light-receiving signal output from the light-receiving unit, when the actual thickness of the object being measured is set as the first thickness and the thickness obtained by multiplying the first thickness by the refractive index of the object being measured is set as the second thickness. The measured object information acquisition unit acquires measured object information including the first thickness, the refractive index, and the refractive index temperature coefficient of the measured object; and The temperature calculation unit calculates the temperature of the measured object based on the second thickness calculated by the thickness calculation unit and the measured object information obtained by the measured object information acquisition unit.

2. The non-contact temperature measuring device according to claim 1, wherein, The measured object information acquisition unit acquires measured object information including the first thickness, the refractive index, the refractive index temperature coefficient, and the linear thermal expansion coefficient of the measured object.

3. The non-contact temperature measuring device according to claim 1 or 2, wherein, The light emitting section emits multiple wavelengths of measurement light toward the surface. The light-receiving unit receives the reflected light for each wavelength and outputs the received light signal. The thickness calculation unit calculates the second thickness for each wavelength based on the light-receiving signal output from the light-receiving unit. The temperature calculation unit calculates the temperature of the measured object based on the second thickness of each wavelength calculated by the thickness calculation unit and the measured object information.

4. A non-contact temperature measuring device, which measures the temperature of a test object having a translucent surface and a back surface in a non-contact manner, wherein... The non-contact temperature measuring device includes: A light emitting section that emits measuring light toward the surface; The light-receiving part receives the reflected light of the measurement light reflected from the surface and the reflected light of the measurement light reflected from the surface through the interior of the object being measured and reflected on the back side of the object being measured on the opposite side of the surface, and outputs a light-receiving signal. The thickness calculation unit calculates the second thickness based on the light-receiving signal output from the light-receiving unit, when the actual thickness of the object being measured is set as the first thickness and the thickness obtained by multiplying the first thickness by the refractive index of the object being measured is set as the second thickness. The relevant data acquisition unit acquires in advance relevant data showing the correlation between the second thickness and the temperature of the object being measured; as well as The temperature calculation unit calculates the temperature of the object being measured based on the second thickness calculated by the thickness calculation unit and with reference to the relevant data obtained by the relevant data acquisition unit.

5. A non-contact temperature measurement method for measuring the temperature of a test object having a translucent surface and a back surface in a non-contact manner, wherein, The non-contact temperature measurement method includes: In the light emission step, measuring light is emitted toward the surface; The light receiving step receives the reflected light of the measurement light reflected on the surface and the reflected light of the measurement light reflected from the surface through the interior of the object being measured and reflected on the back side of the object being measured on the opposite side of the surface, and outputs the light receiving signal. In the thickness calculation step, the actual thickness of the object being measured is set as the first thickness, and the thickness obtained by multiplying the first thickness by the refractive index of the object being measured is set as the second thickness. Based on the light-receiving signal output in the light-receiving step, the second thickness is calculated. The step of acquiring the measured object information includes acquiring measured object information including the first thickness, the refractive index, and the refractive index temperature coefficient of the measured object; and The temperature calculation step calculates the temperature of the measured object based on the second thickness calculated in the thickness calculation step and the measured object information obtained in the measured object information acquisition step.

6. A non-contact temperature measurement method for measuring the temperature of a test object having a translucent surface and a back surface in a non-contact manner, wherein, The non-contact temperature measurement method includes: In the light emission step, measuring light is emitted toward the surface; The light receiving step receives the reflected light of the measurement light reflected on the surface and the reflected light of the measurement light reflected from the surface through the interior of the object being measured and reflected on the back side of the object being measured on the opposite side of the surface, and outputs the light receiving signal. In the thickness calculation step, the actual thickness of the object being measured is set as the first thickness, and the thickness obtained by multiplying the first thickness by the refractive index of the object being measured is set as the second thickness. Based on the light-receiving signal output in the light-receiving step, the second thickness is calculated. The relevant data acquisition step involves pre-acquiring relevant data showing the correlation between the second thickness and the temperature of the object being measured; and The temperature calculation step calculates the temperature of the object being measured based on the second thickness calculated in the thickness calculation step and with reference to the relevant data obtained in the relevant data acquisition step.

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