JP2007271399A - Method and device for measuring temperature of substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To measure the temperature of the substrate in real time by measuring the reflectivity of a laser beam having energy near the critical point (hand gap or the like) in a semiconductor device manufacturing device. <P>SOLUTION: The semiconductor device manufacturing device 3 comprises a photodetector 8 for radiating, from an observation window 4, a first laser oscillator 1 having energy near the critical point (band gap or the like) of the substrate 5 and detecting the quantity of light reflected from the substrate 5. The semiconductor device manufacturing device determines the reflectivity from the amount of reflection, compares it with known reflectivity, and measures the temperature of the substrate 5 in real time. Measurement degradation by dirt or the like of an observation window 4 is corrected using a laser beam of wavelength whose reflectivity hardly varies dependently on the temperature of the substrate 5. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a substrate temperature measuring method and apparatus for measuring a substrate surface temperature and its distribution. Specifically, the present invention relates to a substrate temperature measurement method and apparatus for measuring the surface temperature and distribution of a silicon wafer substrate or the like used for device manufacture.

  In a semiconductor manufacturing apparatus, the temperature of a wafer greatly affects device characteristics and yield. In the process of manufacturing and processing the wafer and the process of manufacturing a device using the wafer, the temperature measurement of the wafer is an important evaluation item. Along with the miniaturization of devices, only the vicinity of the surface of the wafer is rapidly heated to a high temperature, the heat treatment technology that limits the diffusion atomic layer, and the process temperature control becomes strict as the resist material changes, and with high precision, There is a need for a real-time temperature measurement technique capable of measuring temperature distribution.

  Conventional substrate temperature measurement mainly uses a thermocouple method or an infrared method. The thermocouple method is a method of measuring temperature by embedding a thermocouple in a wafer or placing a thermocouple in a wafer holder. The infrared method is a method of measuring thermal radiation from a wafer with a radiation thermometer using radiation formulas such as Stefan-Boltzmann's law and Planck's law.

  However, when a thermocouple is embedded in a wafer, it becomes a contamination source of the device and cannot be used in the manufacturing process. Further, when the thermocouple is embedded in the wafer holder, the temperature of the wafer surface cannot be measured accurately.

  On the other hand, when a radiation thermometer is used, the amount of radiation radiated from the wafer is related to the temperature using a radiation formula, and an estimated radiation coefficient is required for the calculation. Furthermore, when the radiation thermometer is provided outside the observation window, the amount of radiation is changed due to contamination of the observation window, so that accurate temperature measurement cannot be performed.

In contrast to these methods, a method of measuring temperature by irradiating a substrate with light has been proposed. One of them is a method for obtaining the temperature from the amount of reflection of the irradiation light reflected from the substrate. In general, the reflectance when visible light is reflected by silicon varies depending on the temperature of the substrate. The change of the reflectance with the temperature of the substrate is as small as about 10 ⁻⁵ / ° C. When the semiconductor manufacturing apparatus is used indoors, the detector detects illumination light emitted from general illumination, thermal radiation emitted from the semiconductor manufacturing apparatus itself, and the like. For this reason, if the temperature is to be measured from the change in reflectance, the detection sensitivity is limited unless it is a laboratory environment such as the use of a special dark room, and high-precision measurement is difficult.

  Furthermore, for temperature measurement using light irradiation, it is possible to utilize the fact that the critical point (band gap, etc.) energy of silicon decreases with increasing temperature. Where the light absorption coefficient changes, the reflectance also changes. For example, FIG. 1 of Non-Patent Document 1 shows the relationship between the absorption coefficient and the temperature. This reflectance is calculated from the birefringence of light.

  There is a thermometer that measures temperature from the light absorption spectrum, reflection spectrum, transmittance, and the like in the vicinity of the band edge. Patent Documents 1 and 2 disclose optical thermometers using a semiconductor whose light absorption edge changes with temperature as a temperature sensor. That is, a semiconductor temperature sensor is provided inside a temperature sensor attached to the measurement point, and the light to be measured is reflected by a mirror inside the temperature sensor and transmitted through the semiconductor temperature sensor.

Patent Document 3 discloses a temperature measurement method and a semiconductor manufacturing apparatus that irradiates a semiconductor wafer with infrared rays, measures a plurality of wavelengths of the reflected infrared rays and the infrared rays emitted from the semiconductor wafer. Yes.
Appl. Phys. Lett. Vol.41 (7), 1.Oct 1982, p.594-596. Patent Publication No. 59-160725 Patent Publication No. 59-162429 Japanese Patent Publication No. Hei 2-212725

  When using a radiation thermometer, the amount of radiation emitted from the wafer is related to the temperature using a radiation formula, but an estimated radiation coefficient is required for the calculation. Furthermore, when the radiation thermometer is provided outside the observation window, the amount of radiation is changed due to contamination of the observation window, so that accurate temperature measurement cannot be performed.

  The transmittance measurement and the absorption measurement depend on the thickness of the wafer, and not only the surface but also the temperature change inside the wafer is included in the measurement at the same time, so an accurate temperature measurement near the surface cannot be performed. In addition, since reflection spectrum measurement requires spectrum analysis, there are the following problems. Measurement time becomes longer and the number of measurement points is limited to one. Furthermore, there is a problem that the reflection spectrum measuring apparatus becomes complicated.

The present invention has been made based on the technical background as described above, and achieves the following objects.
SUMMARY OF THE INVENTION An object of the present invention is to provide a substrate temperature measuring method and apparatus for directly measuring the surface temperature without contaminating the temperature of a silicon wafer in a semiconductor process cell device.

In order to achieve the above object, the present invention employs the following means.
In the substrate temperature measuring method according to the first aspect of the present invention, the first laser beam is transmitted to the substrate processed in the chamber, which is a closed space, and the first laser beam is transmitted through the chamber. This is a method for measuring the temperature of the substrate by measuring first reflected light that is reflected from the observation window and reflected by the laser light on the substrate.
In the substrate temperature measuring method according to the first aspect of the present invention, the second laser light transmitted through the observation window is irradiated from the observation window simultaneously with the first laser light, and the second laser light is reflected on the substrate. The second reflected light, which is the reflected light, is measured, and from the value of the second reflected light, the first laser light obtains attenuation / dispersion by the observation window, and the reflectance of the first laser light is corrected. The temperature is measured.

  A substrate temperature measuring method according to a second aspect of the present invention is the substrate temperature measuring method according to the first aspect, wherein the first laser beam and the second laser beam are split into two or more irradiation beams by an optical branching unit. Then, the first reflected light and the second reflected light of the two or more irradiated beams are measured separately, which are irradiated from the observation window.

  The substrate temperature measurement method according to a third aspect of the present invention is the substrate temperature measurement method according to the first or second aspect, wherein the second laser beam has a wavelength with a small change in reflectance due to the temperature of the surface of the substrate. It is characterized by that.

  The substrate temperature measurement method of the fourth invention of the present invention is the substrate temperature measurement method of one invention selected from the inventions 1 to 3, wherein the first laser beam is energy in the vicinity of a critical point of the substrate. The reflectivity of the first reflected light varies with a temperature change of the substrate.

  The substrate temperature measuring method according to a fifth aspect of the present invention is the substrate temperature measuring method according to the fourth aspect, wherein the critical point is a band gap.

  A substrate temperature measuring method according to a sixth aspect of the present invention is the temperature measuring method according to one aspect selected from the first to fifth aspects, wherein the substrate is a silicon wafer.

  According to a seventh aspect of the present invention, there is provided the substrate temperature measuring device, the substrate being processed in the chamber that is a closed space, provided outside the observation window of the chamber that transmits laser light, A first laser beam irradiation means for irradiating the first laser beam from an observation window; and a first reflected beam that is a reflected beam reflected by the first laser beam on the substrate. Temperature measuring apparatus comprising: first laser light measuring means provided outside the substrate; and calculation processing means for obtaining the temperature of the substrate from the value of the first reflected light measured by the first laser light measuring means Used in

According to a seventh aspect of the present invention, there is provided a substrate temperature measuring apparatus for irradiating a second laser beam from the observation window simultaneously with the first laser beam, and a second laser provided outside the observation window. A light irradiating means, and a second laser light measuring means provided on the outside of the observation window, for measuring second reflected light that is reflected light reflected from the substrate by the second laser light. Have
The calculation processing means obtains the attenuation amount of the first laser light and the first reflected light by the observation window from the value of the second reflected light detected by the second laser light measuring means, and the first laser The temperature is obtained by correcting the measured value of the light measuring means.

  The substrate temperature measuring apparatus according to an eighth aspect of the present invention is the temperature measuring apparatus according to the seventh aspect, wherein the first laser beam and the second laser beam combined into one beam are transmitted to the observation window. An optical demultiplexing means for demultiplexing into two or more irradiation beams before being irradiated from the first, and two or more reflected beams that are reflected light reflected by the two or more irradiation beams on the substrate. In order to measure each of the reflected light and the second reflected light separately, the first laser light measuring means and the second laser light measuring means corresponding to the number of irradiation beams are provided.

  The substrate temperature measuring apparatus according to a ninth aspect of the present invention is the temperature measuring apparatus according to the seventh or eighth aspect, wherein the second laser beam has a wavelength with a small change in reflectance due to the temperature of the surface of the substrate. Features.

  A substrate temperature measuring apparatus according to a tenth aspect of the present invention is the temperature measuring apparatus according to one aspect selected from the seventh to ninth aspects, wherein the first laser beam has energy near a critical point of the substrate. The first reflected light has a wavelength, and the reflectance of the first reflected light changes according to a temperature change of the substrate.

  A substrate temperature measuring apparatus according to an eleventh aspect of the present invention is the temperature measuring apparatus according to the tenth aspect, wherein the critical point is a band gap.

  A substrate temperature measuring apparatus according to a twelfth aspect of the present invention is the temperature measuring apparatus according to one aspect selected from the seventh to eleventh aspects, wherein the memory stores data indicating the relationship between the temperature of the substrate and the reflectance. And the calculation processing means acquires the temperature corresponding to the measured value from the memory and outputs the temperature when obtaining the temperature from the corrected measured value.

  A substrate temperature measuring apparatus according to a thirteenth aspect of the present invention is the temperature measuring apparatus according to one aspect selected from the seventh to twelfth aspects, wherein the substrate is a silicon wafer.

According to the present invention, the following effects can be obtained.
Since the optical system of the present invention irradiates laser light from the observation window of the device manufacturing apparatus and detects the reflected light from the observation window, temperature measurement is possible without modifying the conventional device manufacturing apparatus.
The laser light applied to the object to be measured has a frequency near a critical point such as a semiconductor band gap, and is sensitive to temperature change, so that temperature measurement can be performed with high accuracy.

Further, the temperature distribution can be measured in real time by irradiating a plurality of locations of the object to be measured with laser light.
By using laser light that is almost independent of the temperature of the object to be measured together with the laser light for measuring the temperature of the object to be measured, dirt on the observation window of the device manufacturing equipment can be corrected, improving measurement sensitivity. Can be made.

  The present invention measures the substrate surface temperature from the change in reflectance of laser light having energy in the vicinity of a critical point (such as a band gap) where the temperature change in reflectance is large, and known reflectance data. The substrate in the device manufacturing apparatus is irradiated with laser light, the amount of reflected light is measured to calculate the reflectance, and the substrate surface temperature is obtained by comparison with known reflectance data.

[First embodiment of the present invention]
A first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a diagram showing an outline of a first embodiment of a temperature measuring device of the present invention. Reference numerals 1 and 11 denote a first laser oscillator and a second laser oscillator. Reference numeral 2 denotes a beam splitter. 3 is a device manufacturing apparatus, 4 is an observation window provided in the device manufacturing apparatus 3, and 5 is a wafer in the device manufacturing apparatus 3. 6 is a beam splitter, 7 and 12 are optical filters, and 8 and 13 are photodetectors.

  The first laser oscillator 1 oscillates a laser beam for measuring the temperature of the wafer 5. The frequency of the laser light oscillated from the first laser oscillator 1 needs to be a frequency near the critical point of the wafer 5. For example, when the wafer 5 is a silicon wafer, the frequency of the laser light oscillated from the first laser oscillator 1 is preferably 1.064 μm or another frequency near the critical point.

  The light detector 8 is a light detector for detecting reflected light reflected from the wafer 5 by the laser light oscillated from the first laser oscillator 1. The optical filter 7 is a band pass filter for transmitting the wavelength of the reflected light. Laser light oscillated from the first laser oscillator 1 passes through the observation window 4 and is irradiated on the wafer 5. When the laser beam passes through the observation window 4, the wafer 5 is irradiated and reflected by the wafer 5. At this time, the frequency of the laser light changes depending on the surface temperature of the wafer 5. The reflected light at this time passes through the observation window 4 again and is detected by the photodetector 8. Laser light oscillated from the first laser oscillator 1 is incident on the wafer 5 at an angle θ with respect to the surface of the wafer 5 and reflected at an angle θ.

  The second laser oscillator 11 is for monitoring the influence of dirt, foreign matter and the like attached to the observation window 4 of the device manufacturing apparatus 3. The second laser oscillator 11 oscillates a laser beam having a wavelength whose reflectance hardly changes depending on the temperature in the device manufacturing apparatus 3. The first laser oscillator 1 and the second laser oscillator 11 can use laser light such as solid, gas, and semiconductor. Further, the first laser oscillator 1 and the second laser oscillator 11 perform continuous oscillation or pulse oscillation.

  The photodetector 13 is for detecting the reflected light of the laser beam oscillated from the second laser oscillator 11. The photodetectors 8 and 13 may be of any kind as long as they detect laser light and output it in proportion to its power. For example, a photodiode such as an APD can be used as the photodetectors 8 and 13.

  The laser light oscillated from the first laser oscillator 1 and its reflected light are disturbed by the influence of dirt on the observation window 4 and foreign matter adhering to the observation window 4, and variations occur when detecting this. In order to compensate for this drawback, the second laser oscillator 11 whose reflectance hardly changes depending on the temperature in the device manufacturing apparatus 3 is used.

  In this example, the wafer 5 is a silicon wafer for semiconductor manufacturing. The beam splitter 2 is a multiplexer for superimposing the laser beams oscillated from the first laser oscillator 1 and the second laser oscillator 11. The laser beams oscillated from the first laser oscillator 1 and the second laser oscillator 11 are overlapped by the beam splitter 2 to form one beam, and are irradiated to the same position (a minute region) of the observation window 4.

  The beam splitter 6 is a beam for separating the reflected light into reflected light for temperature measurement and reflected light for correction by the observation window 4 so that the photodetector 8 and the photodetector 13 can detect the reflected light. It is a splitter. The observation window 4 is normally a window that allows an operator or the like to confirm the processing process in the device manufacturing apparatus 3 with the naked eye, and is made of transparent glass or the like. Observing the observation window 4 is a common practice. If this stain is local, foreign matter may adhere to the entire surface of the observation window 4. Furthermore, the outside of the observation window 4 may become dirty along with the manufacturing process.

  These stains greatly affect the measurement. When the object to be measured (for example, the wafer 5) is emitted from the first laser oscillator 1 or when it is reflected and detected by the object to be measured (for example, the wafer 5), the observation window 4 is not clean. In other words, the observation window 4 passes through the dirt and is attenuated / scattered. For this purpose, the detection accuracy of the reflected light decreases unless the attenuation / scattering due to the dirt is corrected. Therefore, the accuracy of temperature measurement on the surface of the wafer 5 is lowered. The laser light oscillated from the second laser oscillator 11 is for correcting the influence of the observation window 4 on the measurement.

  The photodetectors 8 and 13 detect the reflected light, convert it into an electrical signal, and output it. This electrical signal is input to an electronic computer (not shown) connected to the photodetectors 8 and 13 and processed. Further, in order to monitor the outputs of the first laser oscillator 1 and the second laser oscillator 11, beam splitters 14 and 16 for demultiplexing a part of the laser light, and a photodetector for detecting the laser light. 15 and 17 are provided. Part of the laser light oscillated from the first laser oscillator 1 is demultiplexed by the beam splitter 14 and detected by the photodetector 15.

  Part of the laser light oscillated from the second laser oscillator 11 is demultiplexed by the beam splitter 16 and detected by the photodetector 17. The photodetectors 15 and 17 detect laser light and output an electrical signal. The electrical signals output from the photodetectors 15 and 17 are input to an electronic computer.

[Processing flow of electronic computer]
The electronic calculator calculates and obtains the temperature of the surface of the wafer 5. An example of the flow of processing at this time is shown in the flowchart of FIG. As the measurement is started, the electronic computer receives the electrical signals output from the photodetectors 8 and 13 and the photodetectors 15 and 17 (steps 10 to 16), and internally processes them so that the surface of the wafer 5 is processed. Is calculated (steps 18 to 24). First, a correction value for the observation window 4 is calculated from the electrical signals received from the photodetectors 15 and 17 (step 18). Next, the reflectance of the laser beam is calculated from the data received from the photodetectors 8 and 13 (step 20).

  Laser light oscillated from the first laser oscillator 1 is reflected on the surface of the wafer 5. At this time, the reflectance of the laser light changes depending on the surface temperature of the wafer 5. The reflected laser light is detected by the photodetector 8. The values are compared with the photodetectors 1 and 8, and this value is corrected by the correction value calculated in step 14 to calculate the reflectance. In a storage device such as a built-in hard disk of the electronic computer, known data indicating the relationship between the reflectance of the laser beam and the surface temperature of the wafer 5 is stored. This known data is a value experimentally performed in advance.

  This known data has different values depending on the material of the wafer 5. This known data is measured for each temperature of each material of the wafer 5. The temperature at this time is measured by a method of directly measuring the temperature of the wafer 5. The electronic computer reads this known data from the storage device (step 22). The temperature of the surface of the wafer 5 is calculated by comparing the known data with the reflectance (step 24). The temperature of the wafer 5 calculated by the electronic computer is displayed on the display of the electronic computer (step 26). Therefore, an operator watching the display of the electronic computer can know the temperature of the wafer 5.

  Further, the temperature value of the wafer 5 calculated by the electronic computer is stored in the electronic computer (step 28). The temperature value of the wafer 5 calculated by the electronic computer is passed to an application program operating on the electronic computer (step 30). The temperature value of the wafer 5 calculated by the electronic computer is transmitted to a device or apparatus connected to the electronic computer (step 32). These devices and apparatuses are preferably apparatuses that control and monitor the device manufacturing apparatus 3 based on this data.

  Further, the temperature value of the wafer 5 calculated by the electronic computer can be transmitted to other electronic computers or servers connected to the electronic computer via a communication network and utilized. The electronic computer can control the first laser oscillator 1, the second laser oscillator 11, and the device manufacturing apparatus 3. At this time, the temperature calculated by the electronic computer can be used for the control.

Thus, the reflectance is obtained from the reflected light quantity of the wafer 5 measured in advance, and the temperature of the wafer 5 is further calculated. Since the reflection angle from the wafer 5 can be freely changed, any apparatus having the observation window 4 can be applied. In general, when light is incident on the medium 1 from the medium ₀ at the incident angle θ ₀ , the reflectance R of the light is obtained by the following formula 1 in the direction of the reflection angle θ ₁ .

In the above formula, n ₀ and κ ₀ are the refractive index and extinction coefficient of medium 0, and n ₁ and κ ₁ are the refractive index and extinction coefficient of medium 1. When the medium 0 is vacuum and the angle is fixed, Equation (1) can be modified with A as a constant. Although light having a wavelength of 1.064 μm is hardly absorbed at room temperature, that is, the absorption coefficient is close to 0, but the absorption coefficient increases rapidly as the temperature rises. Since the increase in the absorption coefficient is equivalent to the increase in the extinction coefficient, κ ₁ in Equation 1 increases and the reflectance increases.

  Further, the reflected light from the wafer 5 is received by the CCD camera, the received light image is processed, and the reflection angle is obtained simultaneously with the amount of reflected light. In other words, the reflection angle of the reflected light can be calculated by obtaining the position of the center of gravity of the reflected light. In the case of a silicon substrate, when the temperature is 500 ° C. or higher, light of about 1 μm is thermally radiated from the substrate. Therefore, a temperature equal to or lower than the thermal radiation temperature is preferable. As described above, the present invention does not contaminate the substrate (wafer) by using the laser beam, and directly enters the beam from the observation window of the device manufacturing apparatus during the process, and the surface temperature of the substrate in real time. Can be measured. By using light in the vicinity of the critical point of the substrate material, the reflectivity changes greatly, so that highly accurate temperature measurement is possible. A band gap or the like is preferably used as the critical point of the substrate material.

  Measurement was performed using the temperature measuring apparatus of the first embodiment described above. At this time, reflected light was detected by photodetectors 8 and 13 using a YAG laser having an oscillation wavelength of 1.064 μm for the first laser oscillator 1 and a semiconductor laser having an oscillation wavelength of 810 nm for the second laser oscillator 11. The photodetectors 8 and 13 are silicon photodiodes. Silicon photodiodes were also used as photodetectors 15 and 17 for monitoring the outputs of the first laser oscillator 1 and the second laser oscillator 11. The wafer 5 is a silicon substrate (CZ wafer). The measurement results are illustrated in the graph of FIG. The vertical axis of the graph in FIG. 2 represents the power of reflected light detected by the photodetector 8 (hereinafter referred to as reflected light amount).

  The vertical axis of the graph in FIG. 2 represents the amount of reflected light normalized. The horizontal axis of the graph in FIG. 2 is the surface temperature (° C.) of the wafer 5. The reflectance was obtained from the amount of reflected silicon light measured in advance, and the temperature of the wafer 5 was calculated. It can be seen from the graph of FIG. 2 that the amount of reflected light increases in proportion to the temperature. In FIG. 2, the incident angle is approximately 90 degrees, but the reflectance at an arbitrary angle can be corrected by Equation (1). As can be seen from FIG. 2, the change in the amount of reflected light with respect to temperature is 0.07% / ° C., which is about an order of magnitude higher than the reflectance of light with energy outside the critical point, and temperature can be measured with high accuracy.

[Second Embodiment of the Present Invention]
Other embodiments of the present invention will be described. FIG. 5 is a diagram showing an outline of the temperature measuring device according to the second embodiment of the present invention. In the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted. In the following description, only what is different from the first embodiment will be described. This temperature measuring device measures the temperature of a plurality of locations on the wafer 5 simultaneously. As shown in FIG. 5, a beam splitter 18 for splitting the laser beam and a mirror 19 are provided after the beam splitter 2.

  The laser beam is divided into a plurality of beams by a beam splitter 18 and a mirror 19, becomes a parallel beam, and is irradiated to different locations on the wafer 5. The irradiated plurality of beams are reflected on the surface of the wafer 5. In FIG. 5, the laser beam is divided into three beams by a beam splitter 18 and a mirror 19, and the reflection positions are represented by measurement points 1 to 3. Each of the reflected laser beams is detected by separate light detection units 20-22. The light detection units 20 to 22 include a beam splitter 6, light detectors 8 and 13, and optical filters 7 and 12, respectively. The laser beams are detected by the photodetectors 8 and 13 of the photodetectors 20 to 22, and the detection signals output from the photodetectors 8 and 13 are signal-processed by a subsequent computer (not shown).

  In this way, the surface temperatures at a plurality of locations on the wafer 5 can be measured simultaneously. The irradiation position of the wafer 5 can be changed by changing the arrangement and design of the beam splitter 18 and the mirror 19. Instead of the beam splitter 18, the mirror 19, and the light detection units 20 to 22, any structure and operation can be used as long as it can divide the laser beam into a plurality of beams and irradiate the wafer 5 to detect the reflected light. The principle optical system and optical apparatus may be used, and are not limited by the first or second embodiment of the present invention.

  The present invention is preferably used for measurement of the surface temperature of a wafer in a semiconductor device manufacturing apparatus and real-time measurement thereof.

FIG. 1 is a diagram illustrating an outline of a temperature measuring apparatus according to a first embodiment of the present invention. FIG. 2 is a graph showing the temperature dependence of the amount of reflected light. FIG. 3 is a graph showing the temperature dependence of the reflectance. FIG. 4 is a flowchart showing an example of calculating the wafer surface temperature by the electronic computer. FIG. 5 is a diagram illustrating an outline of a temperature measurement apparatus (a plurality of locations on the wafer 5 are simultaneously measured) according to the second embodiment of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... 1st laser oscillator 11 ... 2nd laser oscillator 2, 6, 14, 16, 18 ... Beam splitter 3 ... Device manufacturing apparatus 4 ... Observation window 5 ... Wafer 7, 12 ... Optical filter 8, 13, 15, 17 ... Photodetector 19 ... Mirror 20, 21, 22 ... Photodetector

Claims (13)

A substrate processed in a chamber that is a closed space is irradiated with a first laser beam from an observation window of the chamber that transmits the first laser beam, and the laser beam is reflected on the substrate. In the method of measuring the temperature of the substrate by measuring the first reflected light that is the reflected light,
Irradiating the second laser beam transmitted through the observation window from the observation window simultaneously with the first laser beam;
Measuring the second reflected light, which is reflected light reflected by the second laser light on the substrate;
The temperature of the substrate is characterized in that the temperature of the substrate is measured by calculating attenuation / dispersion of the first laser light from the observation window from the value of the second reflected light, correcting the reflectance of the first laser light. Measuring method. The method for measuring a temperature of a substrate according to claim 1,
Demultiplexing the first laser beam and the second laser beam into two or more irradiation beams by an optical demultiplexing means, and irradiating from the observation window;
The temperature measurement method for a substrate, wherein the first reflected light and the second reflected light of the two or more irradiation beams are separately measured. In the temperature measuring method of the board | substrate of Claim 1 or 2,
The method of measuring a temperature of a substrate, wherein the second laser light has a wavelength with a small change in reflectance due to a temperature of the surface of the substrate. In the temperature measuring method of the board | substrate of 1 selected from Claims 1-3,
The first laser light has a wavelength having energy near a critical point of the substrate,
The substrate temperature measurement method, wherein the reflectivity of the first reflected light varies with a temperature change of the substrate. The temperature measurement method for a substrate according to claim 4, wherein
The critical point is a band gap. A substrate temperature measurement method, wherein: The temperature measurement method according to claim 1, wherein the temperature measurement method is selected from among claims 1 to 5.
The substrate is a silicon wafer. A first laser for irradiating the first laser light from the observation window provided on the substrate processed in the chamber, which is a closed space, outside the observation window of the chamber that transmits the laser light Light irradiation means;
A first laser beam measuring means provided on the outside of the observation window, for measuring the first reflected beam, which is a reflected beam reflected by the substrate, and the first laser beam; In a temperature measuring device comprising: calculation processing means for obtaining the temperature of the substrate from the value of the first reflected light measured by the measuring means;
A second laser beam for irradiating the second laser beam simultaneously with the first laser beam from the observation window; a second laser beam irradiation means provided outside the observation window; and the second laser beam applied to the substrate. A second laser beam measuring means provided on the outside of the observation window for measuring the second reflected light which is the reflected reflected light;
The calculation processing means obtains the attenuation amount of the first laser light and the first reflected light by the observation window from the value of the second reflected light detected by the second laser light measuring means, and the first laser A temperature measuring apparatus for a substrate, wherein the temperature is obtained by correcting a measured value of a light measuring means. The temperature measuring device according to claim 7,
Optical demultiplexing means for demultiplexing the first laser light combined into one beam and the second laser light into two or more irradiation beams before being irradiated from the observation window;
In order to separately measure the first reflected light and the second reflected light that constitute the two or more reflected beams, which are reflected lights reflected by the substrate from the two or more irradiated beams, the number of the irradiated beams is determined. A substrate temperature measuring device comprising: the corresponding first laser beam measuring unit and the second laser beam measuring unit. In the temperature measuring device according to claim 7 or 8,
The second laser light has a wavelength with a small change in reflectance due to the temperature of the surface of the substrate. In the temperature measuring device according to one selected from Claims 7-9,
The first laser light has a wavelength having energy near a critical point of the substrate,
The substrate temperature measurement device, wherein the reflectance of the first reflected light changes according to a temperature change of the substrate. The temperature measuring device according to claim 10,
An apparatus for measuring a temperature of a substrate, wherein the critical point is a band gap. 12. The temperature measuring device according to claim 1, selected from among claims 7 to 11.
Memory means for storing data indicating the relationship between the temperature of the substrate and the reflectance;
When calculating the temperature from the corrected measurement value, the calculation processing means acquires and outputs the temperature corresponding to the measurement value from the memory. The temperature measuring device according to claim 1 selected from among claims 7 to 12.
The substrate is a silicon wafer.

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