WO2000058701A1

WO2000058701A1 - Temperature measurement system

Info

Publication number: WO2000058701A1
Application number: PCT/JP2000/002005
Authority: WO
Inventors: Tomohiro Suzuki; Shigeru Kasai; Masahiro Shimizu; Minoru Yazawa
Original assignee: Tokyo Electron Limited
Priority date: 1999-03-30
Filing date: 2000-03-30
Publication date: 2000-10-05
Also published as: AU3455400A; KR20010110480A

Abstract

A simplified system is provided in which the temperature of an object to be processed, such as a wafer, is measured by a noncontact thermometer while removing the effects of stray light from a heating lamp. A window material (6) of a chamber (2) is made of fused silica containing hydroxyl groups. The fused silica containing hydroxyl groups is capable of strongly absorbing light in a wavelength range near 2700 nm. A photodetector element (18) and an optical filter (19) on a photodetector (16) are properly selected so that the photodetector (16) may detect only the light at wavelength near 2700 nm, resulting in the elimination of the effects of stray light from the lamp. Since the window material (6) itself functions as a filter, no other filters are required between the lamp (22) and the object to be heated.

Description

Details Temperature measurement technology

The present invention relates to a technique for eliminating the influence of stray light due to light generated by a lamp heating source itself when measuring the temperature of an object heated by the lamp heating source using a radiation thermometer. Background of the Invention

In a film forming process in a semiconductor manufacturing process, a lamp heating source heats a wafer through a susceptor or directly to maintain a wafer to be processed at a predetermined temperature. . In the film forming process, the temperature of the wafer greatly affects the film forming speed and the characteristics of the film, so that the wafer temperature control is very important. As a method of detecting a wafer temperature, a method of measuring thermal radiation from a wafer with a radiation thermometer has been conventionally known.

However, in this method, the light-receiving element of the radiation thermometer simultaneously detects not only heat radiation from the wafer itself but also radiation from the lamp heating source, so the SZN ratio for temperature measurement cannot be sufficiently increased. There is a problem. An example of a conventional temperature measuring system for solving this problem is described in Japanese Patent Application Laid-Open No. H10-111186. The technology disclosed herein includes a filter for cutting light of a specific wavelength provided between a light transmission window provided at the bottom of a chamber and a lamp heating source, and the light-receiving element side of a radiation thermometer. A filter that selectively transmits light of a specific wavelength is provided to eliminate the effects of stray light.

In the conventional system described above, since a plurality of filters are provided between the light transmission window and the lamp heating source, the configuration of the device becomes complicated, and the cost of the device also increases. In addition, since the diameter of the wafer has been increasing in recent years, it is necessary to increase the size of the filter, and the manufacturing cost of the filter becomes a particular problem. Further, in the above-described conventional system, the detection wavelength is not optimized. Disclosure of the invention

The present invention has been made in view of the above circumstances, and has as its object to provide a temperature measurement system capable of performing accurate temperature measurement with a low-cost and simple structure.

In order to achieve the above object, according to a first aspect of the present invention, a temperature measurement system that is housed in a chamber and measures a temperature of an object to be measured that is heated by a lamp heating source includes a lamp heating source, A window material that is provided between the measurement target and has the property of selectively transmitting light outside the specified wavelength range, and a light-receiving element that receives radiation from the measurement target A photodetector that selectively detects light in a wavelength region near a specific wavelength region, and a calculation unit that calculates the temperature of the measurement target based on the output of the photodetector. A temperature measurement system is provided. The window material itself may have a property of selectively transmitting light in a specific wavelength region, and the light detecting means may have a function of selectively detecting light in a wavelength region other than the wavelength region near the specific wavelength region. .

The temperature measurement system includes a light guide disposed in the chamber and transmitting heat radiation from the object to be measured, an optical transmission medium that guides light obtained by the light guide to a light detector, May be further provided.

The window material forms at least a part of a wall that partitions the chamber. This is advantageous in reducing cost and size.

The window material is preferably made of quartz glass having a function of absorbing light in a predetermined wavelength region, for example, quartz glass containing a hydroxyl group.

The light detecting means may further include an optical filter for limiting a wavelength range of light incident on the light receiving element. For example, when the window material is made of quartz glass containing a hydroxyl group, it has a function of selectively transmitting light near a wavelength of 2.7 to the optical filter according to the light absorption characteristics of this quartz glass. Is selected.

Further, according to a second aspect of the present invention, in a temperature measurement system that is housed in a chamber and measures the temperature of a measurement target heated by a lamp heating source, heat radiation from the measurement target is measured. Includes a photodetector having a light receiving element for receiving light, and selectively detects light having a wavelength of 1.5 m or more, more preferably 2.0 or more A temperature measurement system is provided, comprising: a light detection unit; and a calculation unit that calculates a temperature of the measurement target based on an output of the light detector.

In this case, the light detection means can further include an optical filter that limits the wavelength region of the light incident on the light receiving element.

In addition, the temperature measurement system includes an optical guide that is disposed in the chamber and transmits thermal radiation from the object to be measured, and an optical transmission medium that guides the light obtained by the optical guide to the photodetector. May be further provided. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a diagram schematically illustrating an example of a CVD processing device including a temperature measurement system according to a first embodiment of the present invention,

Figure 2 is a graph illustrating the wavelength dependence of the light transmittance of quartz glass corresponding to the hydroxyl group content.

FIG. 3 is a diagram schematically showing another example of the CVD processing device including the temperature measurement system according to the first embodiment of the present invention,

FIG. 4 is a diagram schematically showing still another example of a CVD processing device including the temperature measurement system according to the second embodiment of the present invention,

FIG. 5 is a graph illustrating a method of calculating the contribution of the lamp stray light included in the output voltage of the light receiving element.

Figure 6 is a graph showing the detection wavelength range for each combination of the light receiving element and optical filter used in the experiment.

FIG. 7 is a diagram showing a radiation intensity distribution of radiation light emitted from an object at each temperature, and FIG. 8 is a diagram showing another example of a CVD processing apparatus provided with a temperature measurement system according to the second embodiment of the present invention. FIG. 4 is a diagram schematically showing an example of FIG. Description of the preferred embodiment

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. [First Embodiment]

First, a first embodiment will be described with reference to FIGS. FIG. 1 is a diagram schematically showing a CVD processing apparatus provided with a temperature measurement system according to the present invention. As shown in FIG. 1, the CVD processing apparatus has a chamber 2. When the CVD process such as the film forming process is performed on the wafer 1, the atmosphere in the chamber 2 is isolated from the atmosphere outside the chamber 2. The chamber 2 is defined by a wall 4. Although the chamber 2 is provided with a member such as a gas shower 3 for supplying a processing gas to the wafer 1, it will not be described in detail here because it is not directly related to the gist of the present invention.

At the bottom of the wall 4, a window 6 made of quartz glass containing a hydroxyl group is provided. It is known that quartz glass containing hydroxyl groups has an absorption band around 270 nm (2.7 m) due to vibration of 〇-H, and the intensity of absorption is proportional to the amount of hydroxyl groups contained. . In addition, the quartz glass containing a hydroxyl group also has an absorption band near 220 nm due to the vibration of Si—〇—H, and the absorption intensity in this absorption band is near 270 nm. It is much weaker than the strength of the absorption in the band. Figure 2 is a graph showing the wavelength dependence of the light transmittance of lcm-thick quartz glass for each hydroxyl content ("The World of Quartz Glass", Shin Kuzuu, Industrial Research Institute (1996)). Quote) . As can be understood from this graph, if the hydroxyl group content is 50 pm, light having a wavelength of 270 nm can be absorbed by 90% or more (see the broken line in FIG. 2). Therefore, in practicing the present invention, it is preferable to use, as the window material 6, a quartz glass having a hydroxyl group content of 50 ppm or more. The quartz glass may be formed by a melting method, a synthetic quartz glass, or may be manufactured by a VAD method.

As described above, by using quartz glass containing an appropriate amount of hydroxyl group as the window material 6, a means for selectively transmitting light near the wavelength of 270 nm, that is, light of a wavelength other than light in the specific wavelength region. Can be configured. (Note that this means that when the term “specific wavelength region” is used to mean a wavelength region other than the wavelength region near the wavelength of 270 nm, the “wavelength around the wavelength of 270 nm” It is possible to constitute a means for selectively transmitting light of a wavelength other than the region, that is, light of a specific wavelength region. " It can also be expressed. )

In the chamber 2, a susceptor 8 for mounting the wafer 1, that is, the object to be processed, is provided. The susceptor 8 is preferably formed of black A 1 N, which is advantageous in that the radiation characteristics of the susceptor 8 are close to those of a black body and that the lamp light is difficult to transmit.

The susceptor 8 has a hole 10 that extends from the side surface toward the center and terminates. In the hole 10, a light guide 12 for condensing radiated light from the susceptor 8, that is, a light guide is inserted. The light guide 12 extends through the wall 1 to the outside of the chamber 2. The configuration in which the light guide 12 is inserted into the hole 10 is advantageous in that the amount of lamp light reaching the light guide 12 is minimized.

The light guide 16 is connected to the light guide 12 via an optical fiber 14, that is, an optical transmission medium. The photodetector 16 has a light receiving element 18. The optical detector 16 is provided with an optical filter 19 in front of the light receiving element 18. Appropriate combination of light receiving element 18 having appropriate light receiving sensitivity characteristics (meaning the wavelength dependence of light receiving sensitivity) and optical filter 19 having appropriate transmitting characteristics (meaning the wavelength dependence of transmittance) By combining them, it is possible to constitute a light detecting means for selectively detecting light in a wavelength region around 270 nm (that is, light having a wavelength near a specific wavelength region).

(Note that this means that when the term “specific wavelength region” is used to mean a wavelength region other than the wavelength region near the wavelength of 270 nm, the term “wavelength near the wavelength of 270 nm” It is possible to constitute a means for selectively transmitting light in a specific region, that is, light having a wavelength other than the specific wavelength region. ")

In this example, a thermopile using Sb, Bi (antimony, bismuth) is used as the light-receiving element 18 and a multilayer interference filter is used as the optical filter 19, so that the light-receiving element 18 has a wavelength of about 2700 nm. Light detecting means for selectively detecting light in the above wavelength range.

A temperature controller 24 is connected to the photodetector 16. The temperature controller 24 calculates the temperature of the susceptor 8 based on the principle of Planck's radiation law, and outputs a signal to the lamp 22 based on the temperature of the susceptor 8 calculated by the calculator 26. And an output control unit 28 for controlling the supplied power. Below the chamber 2, a lamp chamber 20 is provided. The lamp chamber 20 is provided with a lamp 22, that is, a lamp heating source.

Next, the operation will be described. When performing the CVD process, the lamp 22 is turned on, and the susceptor 8 is heated by the radiant heat of this lamp. When the susceptor 8 is heated, the wafer 1 placed on the susceptor 8 is heated. When the susceptor 8 is heated, heat radiation is generated from the susceptor 8 corresponding to the temperature. The heat radiation light is condensed by the optical guide 12, passes through the optical fiber 14 and the optical filter 19 sequentially, and enters the light receiving element 18. The output of the light receiving element 18 is input to the calculation unit 26. The calculation unit 26 calculates the temperature of the susceptor 8 based on the output of the light receiving element 18 according to Planck's radiation law. The output control unit 28 supplies electric power to the lamp 22 based on the calculation result of the calculation unit 26 so that the temperature of the susceptor 8 becomes a predetermined value. The light radiated from the lamp 22 is absorbed by the window member 6 in a wavelength region near 270 nm (ie, a specific wavelength region), and the other wavelength regions reach the susceptor 8. The lamp light reaching the susceptor 8 heats the susceptor 8 and transmits through the susceptor 8 to be introduced into the light guide 12 to a small extent.

Therefore, the light introduced into the light guide 12 is radiated light from the susceptor 8 and lamp light in which the wave length region near 270 nm is cut. Here, since the optical filter 19 is provided in front of the light receiving element 18, only the wavelength region near 270 nm of the light introduced into the light guide 12 reaches the light receiving element 18. I do. That is, little or no lamp light reaches the light receiving element 18. Therefore, the effect of stray light from the lamp 22 can be eliminated from the output of the light receiving element 18 and the temperature of the susceptor 8 can be accurately measured.

In the above embodiment, the temperature measurement target is the susceptor 8 on which the wafer 1 to be processed is placed. However, the application of the present invention is not limited to this. However, as shown in FIG. 4, the light guide 12 may be arranged so as to detect the radiation light from the wafer 1 which is the object to be processed. Further, the light guide 12 is disposed above or obliquely above the wafer 1 in the chamber 2 and separated from the wafer 1 so that the light guide 12 detects radiation light from the wafer 1. Is also good. In this case, substantially the same effects as in the above embodiment can be obtained. Further, in the above-described embodiment, the light detecting means for selectively detecting the light in the wavelength region near 2700 nm is configured by combining the light receiving element 18 and the optical filter 19, If the light receiving sensitivity characteristics of the light receiving element 18 are sufficient to achieve the purpose of selectively detecting light in the vicinity of a specific wavelength region, it is possible to configure the light detecting means without the light filter 19. . If a suitable light receiving element 18 is used, a photodiode may be used instead of the thermopile.

Further, in the above embodiment, quartz glass containing a hydroxyl group is used as a material having an optical filter function of absorbing light in a specific wavelength region, but other materials such as sapphire may be used as the window material. May be used. Also in this case, the light receiving element 18 and the optical filter 19 may be appropriately combined in accordance with the absorption wavelength of the window material 6.

[Second embodiment]

Next, a second embodiment of the present invention will be described with reference to FIGS. FIG. 4 is a diagram schematically showing a CVD processing apparatus provided with a temperature measurement system according to the present invention. In FIGS. 4 and 8, components having the same or similar functions as the components shown in FIGS. 1 and 3 are denoted by the same reference numerals.

As shown in FIG. 4, the CVD processing apparatus has a chamber 2. When a CVD process such as a film forming process is performed on the wafer 1, the atmosphere in the chamber 2 is isolated from the atmosphere outside the chamber 2. The chamber 2 is defined by a wall 4. At the bottom of the wall 4, a light-transmitting window material 6 A made of quartz glass is provided. Unlike the window member 6 of the first embodiment, the window member 6A does not need to have an absorption peak in a specific wavelength region. The chamber 2 is provided with members such as a gas shower 3 for supplying a processing gas to the wafer 1, but will not be described in detail here because it is not directly related to the gist of the present invention.

In the chamber 2, a susceptor 8 for mounting the wafer 1, that is, the object to be processed, is provided. The susceptor 8 is preferably formed of black A 1 N, which is advantageous in that the radiation characteristics of the susceptor 8 are close to those of a black body and that the susceptor 8 does not easily transmit lamp light.

The susceptor 8 has a hole 10 extending from its side toward the center and terminating. Has been established. In the hole 10, a light guide 12 for condensing radiated light from the susceptor 8, that is, a light guide is inserted. The light guide 12 extends through the wall 1 to the outside of the chamber 2. Light guide 1 2? The configuration inserted into L 10 is advantageous in that the amount of lamp light reaching the light guide 12 is minimized.

On the other hand, a lamp chamber 20 is provided below the chamber 2. The lamp chamber 20 is provided with a lamp 22A, that is, a lamp heating source. Lamp 22A is a halogen lamp.

In addition, an optical detector 16A is connected to the optical guide 12 via an optical fiber 14, that is, an optical transmission medium. The photodetector 16A has a light receiving element 18A composed of a photodiode or the like.

The photodetector 16A is provided with an optical filter 19A in front of the light receiving element 18A. A light-receiving element 18 A having appropriate light-receiving sensitivity characteristics (meaning the wavelength dependence of light-receiving sensitivity) and a light filter 19 A having appropriate transmission characteristics (meaning the wavelength dependence of transmittance) are used. By appropriately combining them, it is possible to constitute a light detecting means for selectively detecting light in a desired wavelength region. The wavelength region detected by the light detecting means will be described later in detail.

A temperature controller 24 is connected to the photodetector 16A. The temperature controller is a calculator 24 that calculates the temperature of the susceptor 8 based on the principle of Planck's radiation law, and a lamp 2 based on the temperature of the susceptor 8 calculated by the calculator 26. And an output control unit 28 for controlling the power supplied to the power supply 2.

Next, the operation will be described. When performing the CVD process, the lamp 22 A is turned on, and the susceptor 8 is heated by the radiant heat of the lamp. When the susceptor 8 is heated, the wafer 1 placed on the susceptor 8 is heated. When susceptor 8 is heated, susceptor 8 generates heat radiation corresponding to its temperature. The heat radiation light is condensed by the light guide 12, passes through the optical fiber 14 and the optical filter 19 A in order, and enters the light receiving element 18 A. The output of the light receiving element 18 A is input to the calculation unit 26. The calculation unit 26 calculates the temperature of the susceptor 8 based on the output of the light receiving element 18 A according to Planck's radiation law. The output control unit 28 supplies power to the lamp 22A based on the calculation result of the arithmetic unit 26 so that the temperature of the susceptor 8 becomes a predetermined value. Supply.

The light emitted from lamp 22A reaches Susep E8. The lamp light reaching the susceptor 8 heats the susceptor 8 and transmits through the susceptor 8 to be introduced into the light guide 12 though a small amount. Therefore, the light introduced into the light guide 12 becomes the radiation light from the susceptor 8 and the lamp light.

The effect of the lamp light on the temperature measurement result by being included in the light introduced into the light guide 12 can be obtained as follows.

The graph of FIG. 5 shows the change over time of the output voltage Vpd of the light receiving element 18 A and the temperature TS of the susceptor 8.

Now, in the time range t A,

(1) The power W supplied to the lamp 22A is stable and has a substantially constant value Wi, (2) the temperature TS of the susceptor 8 has a stable value Ti, and

(3) It is assumed that the output voltage Vpd of the light-receiving element 18 A is stable and has a substantially constant value Vi.

From this state, the power W supplied to the lamp 22A is set to 0 at the time tl. Then, at that moment, the light from the lamp 22A is not input to the light receiving element 18A, so that the output voltage Vpd of the light receiving element 18A sharply drops from Vi to Vi-AVi. After that, the output voltage Vpd of the light-receiving element 18 A gradually decreases as the temperature TS of the susceptor 8 decreases. The temperature TS of the susceptor 8 gradually decreases after stopping the power supply to the lamp 22A. Therefore, the output voltage drop AVi of the light-receiving element 18 A at the moment when the power supply to the lamp 22 A is stopped corresponds to the contribution of the lamp light included in the output voltage Vi of the light-receiving element 18 A in the time range tA. I do.

Here, R ViZ (Vi-ΔVi) is defined as the intensity ratio index of the radiated light from the lamp 22A to the radiated light from the susceptor 8. This intensity ratio index R is a function of the wavelength range detected by the light detection means. Table 1 shows the relationship. table 1

As shown in Table 1, the intensity ratio index R is 1 or less when the detection wavelength region is 1.5 xm or more, and 0.1 when the detection wavelength region is 2.0 m or more. It is as follows. In other words, a significant improvement is observed compared to the case where the detection wavelength region is less than 1.5 m. Example

Next, the present invention will be described in more detail based on experimental examples. The intensity ratio index R when the detection wavelength region was changed by appropriately combining the light receiving element 18A and the filter 19A was examined. The results are shown in Table 2. Fig. 6 shows the detection wavelength region for each combination of the light-receiving element 18A and the filter 19A used in the test performed to obtain the results shown in Table 2. In Table 2 and FIG. 6, those without a filter show the case where the photodetector is constituted by only the light receiving element 18A without providing the filter 19A. Table ² La: Pump Z: Ratio of radiation intensity ratio R

Ramph. Output InGaAs (L) InGaAs (S) In GaAs (S) Si susef. Temperature (%) + Fi 1 ter + Fi Iter

200 ° C 1 32 .3

2 5 0. C 1 6 1.2

ο U U 丄 0 0. 5 8 R = 6.2 R = = 8. 丄

3 5 0 ° C 1 8 0 .2 7 2 .5 4.1

4 0 0 ° C 2 1 0 .1 5 1 .5 1.7 R = 3 7 0

4 5 0 ° C 2 7 0 .10 0 .7 4 1.3 1 0 0

5 0 ° C 3 2 0 .0 6 7 0 .4 5 0 .7 0 5 6.9

5 2 0. C 30.5 .0 5 8 0 • 3 3 .5 5 31.8 As shown in Table 2, for the light-receiving element 18 A, InGaas (long) and a short length of 1.5 ^ m or less It can be seen that the measurement error can be reduced when combined with the filter 19 A, which cuts the wavelength side. Especially when the temperature of Susceptor 8 is around 500 ° C, the measurement error is very small.

Thus, the emission intensity distribution of the emission light (hereinafter, also referred to as “lamp light”) of a halogen lamp having a color temperature of usually 2000 to 300 ° C. Focusing on the relationship with the radiation intensity distribution of the radiated light from the suscept evening based on the evening temperature (usually 300 ° (: ~ 60 Ot :)) By removing the long region, even if the lamp light enters the light receiving element as stray light, the effect can be minimized.

In other words, as shown in Fig. 7, the emission intensity of the halogen lamp light is strongest in the wavelength range of 0.5 to 1.0 m, so the effect of stray light is minimized by excluding this wavelength region from the detection wavelength region. Limit. Furthermore, the radiation intensity from the susceptor 8 outside the wavelength range of 0.5 to 1.0 m and usually set in the range of 300 ° C to 600 ° C is the strongest. The influence of stray light can be further suppressed by setting the range of 1.5 to 6 zm as the detection wavelength range. As described above, the detection wavelength region is preferably 1.5 / m or more, and more preferably 2.Om or more.

As described above, according to the present embodiment, the wavelength range detected by the light detection unit is By optimizing, the effect of stray light due to lamp light can be eliminated, and highly accurate temperature measurement can be performed.

In the above-described embodiment, the temperature measurement target is the susceptor 8 on which the wafer 1 to be processed is placed, but the application of the present invention is not limited to this. For example, as shown in FIG. 8, the light guide 12 may be arranged so as to detect the radiated light from the wafer 1 which is the object to be processed. Further, the light guide 12 is arranged above or obliquely above the wafer 1 in the chamber 2 so as to be separated from the wafer 1 so that the light guide 12 detects radiation light from the wafer 1. You may. In this case, substantially the same effects as in the above embodiment can be obtained.

In the above embodiment, the light detecting means for selectively detecting light in a predetermined wavelength region is configured by combining the light receiving element 18A and the optical filter 19A. If the light-receiving sensitivity characteristic of 8 A is sufficient to achieve the purpose of selectively detecting light in the vicinity of a specific wavelength region, the light detecting means can be configured without the optical filter 19 A.

Claims

The scope of the claims

1. In a temperature measurement system that measures the temperature of an object to be measured housed in a chamber and heated by a lamp heating source,

A window member provided at a portion between the lamp heating source and the object to be measured, which has a property of selectively transmitting light outside a specific wavelength region;

A photodetector having a light receiving element for receiving thermal radiation light from the measurement object, a photodetector that selectively detects light in a wavelength region near the specific wavelength region, And a calculation unit for calculating the temperature of the measurement target based on the output.

2. In a temperature measurement system that measures the temperature of an object to be measured housed in a chamber and heated by a lamp heating source,

A window member provided at a portion between the lamp heating source and the object to be measured, which has a property of selectively transmitting light in a specific wavelength region itself;

A photodetector including a photodetector having a light receiving element for receiving thermal radiation light from the measurement object, and a light detection unit for selectively detecting light outside a wavelength region near the specific wavelength region,

A calculation unit for calculating the temperature of the object to be measured based on the output of the photodetector.

3. a light guide arranged in the chamber for transmitting heat radiation from the object to be measured;

The temperature measurement system according to claim 1, further comprising: an optical transmission medium that guides light obtained by the light guide to the photodetector.

4. The temperature measurement system according to claim 1, wherein the window material forms at least a part of a wall that partitions the chamber.

5. The temperature measurement system according to claim 1, wherein the window material is made of quartz glass having a function of absorbing light in a predetermined wavelength range.

6. The temperature measurement system according to claim 5, wherein the quartz glass contains a hydroxyl group.

7. The temperature measurement system according to claim 1, wherein the light detection unit further includes an optical filter that limits a wavelength range of light incident on the light receiving element.

8. The window material is made of quartz glass containing a hydroxyl group,

The temperature measurement system according to claim 7, wherein the optical filter has a function of selectively transmitting light having a wavelength of about 2.7 m.

9. In a temperature measurement system that measures the temperature of an object to be measured housed in a chamber and heated by a lamp heating source,

A photodetector including a photodetector having a light receiving element for receiving thermal radiation light from the object to be measured, a photodetector for selectively detecting light having a wavelength of 1.5 m or more; and And a calculation unit for calculating the temperature of the measurement target based on the output.

10. The temperature measurement system according to claim 9, wherein the light detection means selectively detects light having a wavelength of 2.0 m or more.

11. The temperature measurement system according to claim 9, wherein the light detection unit further includes an optical filter that limits a wavelength region of light incident on the light receiving element.

12. A light guide disposed in the chamber for transmitting heat radiation light from the object to be measured;

The temperature measurement system according to any one of claims 9 to 11, further comprising: an optical transmission medium that guides light acquired by the light guide to the photodetector.