JP2003214956A - Temperature measuring method and device, semiconductor device manufacturing method, and memory medium - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a temperature measuring method and device, a semiconductor device manufacturing method, and a memory medium, capable of accurately measuring the temperature of an object in the presence of light emitted by a surrounding body. <P>SOLUTION: The light emitted by an object 11 to be measured and the light reflected therefrom are measured at a plurality of wavelengths, and the emissivity of the object 11 is calculated by using the measurement of the reflected light. An equation is constructed, based on the values measured at the plurality of wavelengths, on the assumption that the emissivity of a surrounding body 12 is not dependent on wavelengths or that the value of its emissivity is known if dependent on the wavelengths. The temperatures of the object 11 to be measured and of the surrounding object 12 are determined by obtaining a solution satisfying the equation in the highest degree. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a temperature measuring method for measuring the temperature of an object by measuring the emitted light of the object,
The present invention relates to a temperature measuring device, a semiconductor device manufacturing method, and a storage medium.

[0002]

2. Description of the Related Art Conventional radiation thermometers include a monochromatic thermometer for measuring radiation of a single wavelength and a bicolor thermometer for measuring radiation of two wavelengths. The monochromatic thermometer inputs the emissivity into a measuring device and multiplies the emissivity by Planck's radiation law to calculate the temperature. The two-color thermometer assumes that the emissivity of the measuring object is equal between the two wavelengths to be measured, and measures the temperature from the ratio of the measured values between those two wavelengths.

Further, a measuring method of a two-color radiation thermometer, which is capable of measuring the temperature of a measuring object in consideration of radiated light of surrounding objects, is also under study. Here, only the case where the emissivity of the measurement object is constant regardless of the wavelength, the temperature of the surrounding object is known, and the surrounding object is a black body having an emissivity of 1 is considered. (Reference 1: Proceedings of the Japan Opportunity Society, 64, 6
No. 24, Paper No. 97-1271)

[0004]

For example, when the temperature of a wafer is measured in a semiconductor processing apparatus or the like, the emitted light from the outer wall of the process apparatus is reflected on the wafer surface, and the emitted light from the wafer itself and other emitted light are reflected. Overlap and impinge on the measuring device. In this way, when the radiated light from the surroundings other than the measuring object is incident on the measuring device, neither the monochromatic thermometer nor the two-color thermometer can distinguish between the radiated light from the measured object and the radiated light from the surroundings. Since it is regarded as the emitted light from the measurement object, an error occurs in the temperature measurement.

Further, the measurement method of the two-color radiation thermometer of the above-mentioned reference 1 is valid only when the surrounding object is a black body having an emissivity of 1. However, this method cannot be used because the outer wall of a semiconductor process device or the like is not a black body. Furthermore, since the measurement object also uses the assumption of the two-color thermometer that the emissivity is the same between the measurement wavelengths, it cannot be applied to a measurement object having different emissivity between the two wavelengths.

In the case of a monochromatic thermometer, the user needs to investigate or measure the emissivity of the measuring object by some method and input it into the measuring device as a known constant. In the case of the two-color thermometer, the temperature can be measured only by the measuring object having the same emissivity between the two wavelengths. When the emissivity changes during temperature measurement, the monochromatic thermometer needs to measure the emissivity in real time and feed it back to the thermometer. In a two-color thermometer, if the change in emissivity is not equal between the two wavelengths, a large temperature measurement error will occur.

An object of the present invention is to provide a temperature measuring method, a temperature measuring device, a semiconductor device manufacturing method, and a storage medium, which can accurately measure the temperature of a measuring object even if there is radiation from a surrounding object. It is in.

[0008]

In order to solve the above problems and achieve the object, a temperature measuring method, a temperature measuring device, a semiconductor device manufacturing method, and a storage medium of the present invention are configured as follows.

In the temperature measuring method of the present invention, the emitted light and the reflected light of the measurement object are measured at a plurality of wavelengths, the emissivity of the measurement object is calculated from the measurement result of the reflected light, and the emissivity of the surrounding object is calculated. Is assumed to be wavelength-independent, or if it depends, it is assumed to be a known value, an equation is constructed from the measurement results at each measurement wavelength, and the solution that best satisfies this equation is obtained to determine the temperature of the measurement object. And measuring the temperature of the surrounding object.

A temperature measuring apparatus of the present invention is equipped with an algorithm according to the above-mentioned temperature measuring method, and comprises a light source for illuminating the measuring object, and a first light transmitting means for transmitting illumination light from the light source to the measuring object. A spectroscopic unit that disperses a desired wavelength in the emitted light and the reflected light of the measuring object and guides it to a plurality of light receiving elements; and a second light transmitting unit that transmits the emitted light and the reflected light of the measuring object to the spectroscopic unit. , A light receiving means for amplifying an output from the light receiving element.

According to the method of manufacturing a semiconductor device of the present invention, a semiconductor device is manufactured by using the above temperature measuring method.

The storage medium of the present invention can be read by a computer, and the emitted light and the reflected light of the measurement object are measured at a plurality of wavelengths, and the emissivity of the measurement object is calculated from the measurement result of the reflected light. , It is assumed that the emissivity of the surrounding object does not depend on the wavelength, or if it depends, it is assumed that it is a known value, and an equation is constructed from the measurement results at each measurement wavelength, and the solution that best satisfies this equation is obtained. , A program for measuring the temperature of the measuring object and the temperature of the surrounding object is stored.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a diagram showing a temperature measurement model according to an embodiment of the present invention. In the present embodiment, based on the temperature measurement model shown in FIG. 1, the emitted light of the measurement object 11 and the emitted light of the surrounding object 12 reflected by the surface of the measurement object 11 are measured via the optical transmission device 3. Consider the case of incidence on an optical system.

Here, the emissivity εs (λ, Ts) of the measuring object
Varies depending on the wavelength, but it can be measured by means described separately. Assuming that the emissivity εo of the surrounding object is equal for each wavelength to be measured, the unknowns are three variables: the temperature Ts of the measuring object, the temperature To of the surrounding object, and the emissivity εo of the surrounding object.
Therefore, temperature measurement is performed at three different wavelengths, three equations are established, and from the simultaneous equations of these equations, Ts, T
By solving o and εo by numerical analysis, the temperature Ts of the measuring object can be measured.

The emissivity εs (λ, Ts) of the measuring object can be obtained by measuring the reflectance ρs (λ, Ts) of the measuring object. If the emissivity depends on wavelength and temperature, it must be measured in real time. Therefore, the illumination light is applied to the measurement object, and the reflected light and the radiation light from the measurement object are alternately measured to calculate the emissivity εs (λ, Ts) of the measurement object.

First, a method of obtaining the emissivity will be described.
The following relationship holds between the emissivity ε, the reflectance ρ, and the transmittance τ according to the law of conservation of energy.

Ε + ρ + τ = 1 (1) Here, as the measurement wavelength, it is assumed that the transmittance τ of the measurement object is 0, that is, a wavelength that does not transmit. In this case, the emissivity ε
The following equation (2) is established between and the reflectance ρ, and the emissivity can be obtained by measuring the reflectance of the measurement object.

Ε = 1-ρ (2) Next, the law of radiation will be described. According to Planck's radiation law, assuming that the object temperature is T, the spectral radiant energy L (λ, T) from an object having an emissivity ε (λ, T) is expressed by the following equation (3). Here, Lb (λ, T) is the spectral radiant energy of a black body having an emissivity ε (λ, T) of 1.

L (λ, T) = ε (λ, T) · Lb (λ, T) (3) Conversion between light energy incident on the sensor of the measuring device and output voltage V (λ, T) of the sensor If the coefficient is α (λ),
Spectral radiant energy L (λ, T) and sensor output voltage V
The relationship with (λ, T) is generally expressed by the following equation (4).

V (λ, T) = α (λ) · L (λ, T) (4) A characteristic representing the relationship between the spectral radiant energy L (λ, T) of the measurement object and the temperature T of the measurement object. Let the function be f (λ, T). Various characteristic equations have been considered for this f (λ, T). An example is given below. A of each characteristic formula,
B, C, and n are constants obtained by measuring and calculating the radiant light of the blackbody furnace. This value depends on the measurement wavelength λ. Further, c2 is the Planck's second radiation constant.

V (λ, T) = f (λ, T) (5) V (λ, T) = C (λ) · exp {−c2 / (A (λ) · T + B (λ))} (5-1) V (λ, T) = C (λ) / [exp {c2 / (A (λ) · T + B (λ))} −1] (5-2) V (λ, T) = C (λ) · T ^{n (λ)} ... (5-3) V (λ, T) = C (λ) · T ^{n (λ)} · exp (−B (λ) / T) ... (5-4) The temperature of the measuring object is Ts, and the emissivity of the measuring object is εs (λ, T
s), the reflectance of the measuring object is ρs (λ, Ts), the temperature of the surrounding object is To, the emissivity of the surrounding object is εo (λ, To), and the sensor output voltage of the measuring device is V (λ, Ts). To do.

In Reference 1 above, the emissivity ε of the measuring object is
s (λ, Ts) is the wavelength λ, ε is a constant that does not depend on temperature Ts, emissivity εo (λ, To) of the surrounding object is 1, which is a black body, and the temperature To is known to be known. . In this case, V (λ, Ts) is expressed as follows using equations (2), (3) and (4).

V (λ, Ts) = α (λ) · {ε · f (λ, Ts) + (1-ε) · f (λ, To)} (6) Measurement at two different wavelengths λ1 and λ2 Letting the output voltages measured for the object be V1 and V2, the equation (6) can be rewritten as follows. Here, α1 and α2 are conversion coefficients at wavelengths λ1 and λ2.

V1 = α1 · {ε · f (λ1, Ts) + (1-ε) · f (λ1, To)} (7) V2 = α2 · {ε · f (λ2, Ts) + (1 -[Epsilon]) f ([lambda] 2, To)} (8) In Reference 1, the characteristic function f ([lambda], T) uses the formula (5-3) of exponential approximation. Using this approximation (7),
The expression (8) is expressed as follows.

V1 = α1 · {ε · C1 × Ts ⁿ¹ · (1-ε) · Co1 × To ^no1 } = ε · a1 × Ts ⁿ¹ · (1-ε) · ao1 × To ^no1 (7) ′ V2 = Α2 · {ε · C2 × Ts ⁿ² · (1-ε) · Co2 × To ^no2 } = ε · a2 × Ts ⁿ² · (1-ε) · ao2 × To ^no2 (8) ′ where a1, ao1, a2, ao2, n1, no1,
n2 and no2 are constants peculiar to the measuring device, which can determine the measurement wavelength and the measurement temperature range. This constant is obtained by calibrating the measuring device with a black body furnace or the like.

By solving the equation (7) 'with respect to ε and substituting it into the equation (8)' and eliminating ε, an equation relating to Ts is obtained.
If the solution of this equation is obtained by numerical analysis, Ts can be estimated. As described above, when the emissivity of the measurement object is constant regardless of the wavelength, the temperature of the surrounding object is known, and the surrounding object can be regarded as a black body, the temperature can be obtained by measuring the two wavelengths.

However, the emissivity of many objects depends on the wavelength, and it is rare when the surrounding object can be regarded as a black body, and this measuring method cannot be used. As an example, consider the case where the temperature of a wafer is measured in a semiconductor manufacturing process. When the temperature of the wafer is measured from the back surface of the wafer in the film forming process chamber, the film is attached to the back surface of the wafer in the previous step. In this case, the emissivity of the wafer depends on the wavelength. Therefore, equation (7) '
Equation (8) 'cannot be used.

Therefore, a new temperature measurement algorithm was constructed for the case of measuring the reflectance of the wafer for each wavelength. The reflectance of the measured object at each wavelength is ρ1, ρ2, ρ
3. Emissivity of surrounding objects is εo1, εo2, εo3, and output voltages are V1, V2, and V3. However, measurement wavelengths λ1, λ
Lights of 2 and λ3 do not pass through the wafer.

V1 = α1 · {(1-ρ1) · f (λ1, Ts) + ρ1 · εo1 · f (λ1, To)} (9) V2 = α2 · {(1-ρ2) · f (λ2, Ts) + ρ2 ・ εo2 ・ f (λ2, To)} (10) V3 = α3 ・ {(1-ρ3) ・ f (λ3, Ts) + ρ3 ・ εo3 ・ f (λ3, To)} (11) Here When the emissivity εo1, εo2, εo3 of the surrounding object is unknown, there are five unknown variables Ts, To, εo1, εo2, εo3. If εo1, εo2, and εo3 can be measured in the same way as the measurement object, the two equations can be solved to find Ts and To, but it is difficult to measure the emissivity of surrounding objects in the actual semiconductor manufacturing process. is there. However, it is possible to make or cover the surrounding object with a gray body material, such as gold, silicon, or quartz, which has the same emissivity over a certain wavelength band. Therefore, if the measurement wavelengths λ1, λ2, λ3 are in this wavelength band, the emissivity of the surrounding object can be set as a constant εo. Then, the temperature model equations (9), (10),
(11) is expressed as follows.

V1 = α1 · {(1-ρ1) · f (λ1, Ts) + ρ1 · εo · f (λ1, To)} (12) V2 = α2 · {(1-ρ2) · f (λ2, Ts) + ρ2 · εo · f (λ2, To)} (13) V3 = α3 · {(1-ρ3) · f (λ3, Ts) + ρ3 · εo · f (λ3, To)} (14) This In the temperature model formula, the unknowns are three variables of Ts, To, and εo, and if these three formulas are made simultaneous and Ts, To, and εo that satisfy these are obtained by numerical analysis, the temperature Ts of the measured object is accurately obtained. be able to. This group of equations is the new temperature measurement algorithm proposed in the present invention.

In the conventional algorithm, the temperature can be measured only when the emissivity of the measuring object is equal between the measuring wavelengths and the surrounding object is a black body. However, with the algorithm of the present invention, it is possible to measure even when the emissivity of the measurement object differs between wavelengths, and by setting the emissivity of the surrounding object to not the black body 1 but the unknown number εo of the gray body, Real-world measurement is possible.

Next, an example of the temperature estimation algorithm in the present invention will be described.

An exponential approximation of (5-
The expressions (12), (13), and (14) are expressed using the expression (3), and the following expressions are obtained.

V1 = (1-ρ1) · a1 × Ts ⁿ¹ · ρ1 · εo · ao1 × To ^no1 ... (15) V2 = (1-ρ2) · a2 × Ts ⁿ² · ρ2 · εo · ao2 × To ^no2 ... (16) V3 = (1-ρ3) · a3 × Ts ⁿ³ · ρ3 · εo · ao3 × To ^no3 (17) Eliminating εo and To from the above equation, the equation g (T
(18) can be obtained by setting s).

[0036]

[Equation 1] Ts that satisfies this g (Ts) = 0 is the temperature of the measurement object.

FIG. 2 shows g (Ts) when Ts is changed.
It is a graph showing the behavior of. G123 and g23 in the figure
1 and g312 show the difference due to the combination of the equations, both equations have g (T
It can be seen that s) = 0. This Ts can be obtained by numerical calculation using a method such as the Newton method. Further, To and εo can be obtained from the equations (19) and (20).

FIG. 3 is a diagram showing the result of comparison of the estimation accuracy of the measured object temperature Ts when the conventional technique and the algorithm of the present invention are used, and FIG. 3A shows the two-color temperature measurement result of the conventional technique. FIG. 1B is a diagram showing a temperature measurement result by the algorithm of the present invention. The temperature To of the surrounding object in the simulation is 775 K, and the emissivity εo of the surrounding object is 0.9. Under this condition, the temperature Ts of the measurement object is changed, and according to the prior art, the equations (7) ′ and (8) ′, and the algorithm of the present invention are represented by equations (18), (19), and (20). The temperature Ts was estimated.

As shown in FIG. 3A, since the surrounding object is a black body in the prior art, the temperature of the measured object has an error of about 2K in the high temperature part and about 15K in the low temperature part. As shown in FIG. 3B, the algorithm of the present invention has an error of 0.2 K or less in both the low temperature part and the high temperature part,
It can be seen that the algorithm of the present invention is significantly superior to the prior art.

In the above description, the exponential approximation of the equation (5-3) is used for the characteristic function, but (12), (13), (14)
The equations (5-1), (5-2), (5-4), and various other characteristic functions can be applied to the equations to estimate the temperature Ts of the measurement object by numerical analysis. Further, some characteristic functions have a narrow temperature range in which accurate approximation can be performed. In this case, the approximate temperature range is finitely divided,
It is necessary to store the approximate coefficient as a calculation coefficient in a table or the like and estimate the temperature Ts of the measurement object while shifting the estimated temperature range.

Next, a temperature measuring device equipped with the above-described algorithm of the present invention will be described.

FIG. 4 is a diagram showing the structure of a temperature measuring device 100 equipped with the algorithm of the present invention. Light source device 1
Generates an illumination light 15 for illuminating the measuring object 11. The chopper device (or shutter device) 2 projects or blocks the illumination light from the light source device 1. The optical transmission device 3 includes a bundle fiber or the like, guides the illumination light to the measurement object 11 in the surrounding object 12, and transmits the reflected light 16 and the emitted light 13 from the measurement object 11 to the spectroscopic device 4.

The spectroscopic device 4 disperses three desired wavelengths from the received light, and the sensor (light receiving element) receives the light. The light receiving device 5 is composed of an amplifier or the like having a function of amplifying the output of the sensor and removing noise with a filter or the like. The chopper device 6 allows light to enter the light-splitting device 4 and blocks light. The optical transmission device 7 includes an optical fiber that transmits a part of the illumination light to the spectroscopic device 8 described later.

Similar to the spectroscopic device 4, the spectroscopic device 8 disperses the desired three wavelengths from the illumination light received from the light source device 1 and receives them by the sensor. The light receiving device 9 measures the light amount change of the light source device 1 from the output of the sensor. The control device 10 is composed of a computer or the like, has a function of controlling the light source device 1, the chopper device 2, and the chopper device 6 and collecting signals from the light receiving devices 5 and 9 to estimate the temperature. Stored in internal memory.

When the chopper device 2 is closed, the measuring object 11
The illumination light of the light source device 1 is not radiated. In this state, the emitted light 13 of the measurement object 11 and the emitted light 14 of the surrounding object 12 are incident on the optical transmission device 3. These synchrotron radiation 1
3 and 14 pass through the optical transmission device 3 and enter the spectroscopic device 4 when the chopper device 6 is open. The radiated lights 13 and 14 that have entered the spectroscopic device 4 are split into three wavelengths as follows.

FIG. 5 is a diagram showing the structure of the spectroscopic device 4. The radiated lights 13 and 14 that have entered the spectroscopic device 4 are collimated by the collimator lens 17 and then divided into three by the half mirrors 181 and 182, respectively, and only the lights 201, 202 and 203 in the desired specific wavelength range interfere. The light is transmitted through the filters 191, 192, and 193, and the condenser lens 21
The sensor 22 in the light receiving device 5 by 1, 212, 213
It is focused on 1, 222, and 223. Then, the light receiving device 5
Outputs output voltages Ve1, Ve2, Ve3.

On the other hand, when the chopper device 2 is open, the illumination light of the light source device 1 passes through the optical transmission device 3 and illuminates the measurement object 11. In this case, from the measurement object 11 to the measurement object 1
The reflected light 16 of 1, the emitted light 13 of the measuring object, and the emitted light 14 of the surrounding object are emitted. These lights 13, 14, 1
6 passes through the optical transmission device 3 and enters the spectroscopic device 4 when the chopper device 6 is open. Furthermore, each light 13, 14,
As described above, 16 is split into three wavelengths by the spectroscopic device 4, and the light intensity is measured by the light receiving device 5. The output voltages Vr1, Vr2, Vr are output from the light receiving device 5.
3 is output.

A part of the illumination light of the light source device 1 is guided to the spectroscopic device 8 by the optical transmission device 7. The spectroscopic device 8 has the same configuration as the spectroscopic device 4, and disperses the desired three wavelengths from the illumination light of the light source device 1 and receives them by the sensor. The light receiving device 9 measures the variation of the illumination light amount of the light source device 1 from the output of the sensor. Then, the output voltages Vo1, Vo2, Vo3 are output from the light receiving device 9.

When both the chopper device 2 and the chopper device 6 are closed, the light receiving device 5 outputs a dark signal including stray light inside the device and noise of the electrical system. Then, the output voltages Vd1, Vd2, and Vd3 are output from the light receiving device 5.

As described above, by controlling the opening and closing of the chopper devices 2 and 6 by the control device 10, dark measurement, measurement of emitted light 13 and emitted light 14, emitted light 13 and emitted light 14 are performed.
And the reflected light 16 can be sequentially measured.

The reflectance of the measuring object 11 is obtained by the following method. The reflectance without heat radiation is ρref1, ρref2, ρref3
The output voltage when the reflected light of the standard object is measured by the light receiving device 5 is Vref1, Vref2, and Vref3 at each wavelength.
At this time, the reflectances ρ1, ρ2, ρ3 of the measurement object 11 are
It becomes the following formula.

Ρ1 = (Vr1-Ve1) / Vref1 · ρref1 ρ2 = (Vr2-Ve2) / Vref2 · ρref2 ρ3 = (Vr3-Ve3) / Vref3 · ρref3 The reflectances ρ1, ρ2, and ρ3 are described above. (18)
Substituting into the equation g (Ts) of, the temperature Ts of the measuring object 11, the temperature To of the surrounding object 12, the emissivity ε of the surrounding object 12
You can ask o.

Further, when the amount of illumination light of the light source device 1 fluctuates, if the output voltage of the light receiving device 9 when measuring Vref1, Vref2, Vref3 is Voref1, Voref2, Voref3, the reflectance ρ1, It is necessary to correct ρ2 and ρ3 as in the following equation.

Ρ1 = (Vr1-Ve1) / Vref1 · ρref1 · Voref
1 / Vo1 ρ2 = (Vr2-Ve2) / Vref2 · ρref2 · Voref
2 / Vo2 ρ3 = (Vr3-Ve3) / Vref3 · ρref3 · Voref
3 / Vo3 Further, the sensor and the amplifier system of the light receiving devices 5 and 9 have an IC
It is equipped with a temperature sensor and can also correct the temperature drift of the sensor and amplifier.

FIGS. 6A and 6B are views showing an example of the structure of the light source device 1. In the present embodiment, FIG.
As shown in FIG. 6, a continuous lighting type light source 51 such as a halogen lamp having a broad emission wavelength is used, irradiation is performed by a dichroic mirror 52, and measurement of emitted light, reflected light, and dark is switched by a chopper. (B)
As shown in, it is also possible to use a light source 53, such as an LED, which can be pulse-driven in the sub-band of the emission wavelength, and irradiate it with a condenser lens 54. In this case, it is possible to perform measurement by receiving the emitted light, the reflected light and the dark with the light receiving devices 5 and 9 in synchronization with the light emission pattern (pulse timing) of the LED. Further, the LEDs are not limited to one color, and it is possible to combine several kinds of LEDs having a required wavelength. In addition to LEDs, lasers and the like can be used for the light source device.

7A and 7B are views showing a structural example of the optical transmission device 3, in which FIG. 7A is a transverse sectional view and FIG. 7B is a front sectional view.
In the present embodiment, the light source transmission device 3 has a configuration shown in FIG.
Bundle fiber 31 and lot 32 as shown in (b)
Is used. In the bundle fiber 31, one illumination fiber 33 that guides the light from the light source device 1 to the measurement object 11 is centered, and several light receiving fibers 34 that receive the emitted light and the reflected light are bundled around the illumination fiber 33. The tip of the bundle fiber 31 is connected to a lot 32 of sapphire or the like having excellent heat resistance and chemical resistance so that it can be incorporated into the semiconductor device. The optical transmission device 3 is not limited to the bundle fiber and may be any transmission device that can guide the light of the light source device 1 to the measurement object 11 and guide the reflected light to the spectroscopic device 4 again.

FIG. 8 is a diagram showing a modification of the spectroscopic devices 4 and 8. In the above embodiment, as shown in FIG. 5, the interference filters 191 and 192 are added to the optical spectrum of the optical transmission device 3.
Although 193 is used, this spectroscopy can be performed using a diffractive optical system such as a diffraction grating (spectrometer) 24 as shown in FIG. In this case, the emitted light and the reflected light that have passed through the slit 23 are each divided into three by the diffraction grating 24, and are condensed on the sensors 221, 222, 223. Further, as the sensors 221, 222, 223, not only a single light receiving element such as a silicon sensor but also a line sensor such as CCD can be used.

In the above-mentioned embodiment, the case of measuring with light of three wavelengths is described, but g (Ts) can be extended to four or more wavelengths. That is, g123 (Ts), g234 (Ts), g345 for each wavelength combination.
(Ts) can be created, gijk (Ts) can be solved, and Ts can be optimized. This is particularly effective when the emissivity changes extremely, such as during film formation.

As described above, in the present embodiment, the emissivity of the measurement object differs between the measurement wavelengths, and the surrounding object is not a black body but is a gray body whose emissivity is equal between the measurement wavelengths. , A multi-wavelength temperature measurement model that takes into consideration the ambient radiation other than the measurement object was set up, and a radiation temperature measurement algorithm that can accurately measure the temperature of the measurement object even with the radiation of the surrounding object was constructed.

Furthermore, in order to measure the emissivity of the measurement object in real time by mounting the above algorithm, a light source device for illuminating the measurement object, a light from the light source device to the measurement object, reflected light from the measurement object, and An optical transmission device for transmitting radiated light to a light receiving device, a spectroscopic device for splitting the received light into a desired wavelength, a light receiving device for receiving the split light, and switching between the reflected light and the radiated light and guiding them to the light receiving unit. With a temperature measuring device having a chopper device and a control device such as a computer having a function of controlling them and estimating the temperature, the temperature of the measuring object can be accurately measured even if there is radiant light from the surrounding object. A radiation temperature measuring device was constructed.

The present invention is not limited to the above-mentioned embodiments, but can be carried out by appropriately modifying it without departing from the scope of the invention. For example, the temperature measurement method shown in the above embodiment,
By applying the method to the wafer temperature measurement in the semiconductor device manufacturing process, the temperature of the measurement object can be measured even when the emissivity of the measurement object changes for each sample or during the temperature measurement.

[0062]

According to the present invention, there are provided a temperature measuring method, a temperature measuring device, a semiconductor device manufacturing method, and a storage medium, which can accurately measure the temperature of a measuring object even if there is radiated light from a surrounding object. it can.

That is, use a method of constructing a temperature measurement algorithm in consideration of the wavelength dependence of the emissivity of the measuring object and the influence of the radiation of the surrounding object, and measuring the emissivity of the measuring object at three or more different wavelengths. This makes it possible to measure the temperature of the measurement object even when the emissivity of the measurement object changes from sample to sample or during temperature measurement, as in the wafer temperature measurement in a semiconductor process.

Even when the radiation from the surrounding objects such as the heater around the wafer and the chamber wall is incident on the wafer surface and cannot be distinguished from the radiation from the wafer, the temperatures of the measurement object and the surrounding objects can be accurately measured. Can be measured.

[Brief description of drawings]

FIG. 1 is a diagram showing a temperature measurement model according to an embodiment of the present invention.

FIG. 2 is a graph showing the behavior of simultaneous equations of the algorithm according to the embodiment of the present invention.

FIG. 3 is a diagram showing a comparison result of temperature estimation accuracy by an algorithm of the related art and that of the present invention.

FIG. 4 is a diagram showing a configuration of a temperature measuring device according to an embodiment of the present invention.

FIG. 5 is a diagram showing a configuration of a spectroscopic device according to an embodiment of the present invention.

FIG. 6 is a diagram showing a configuration of a light source device according to an embodiment of the invention.

FIG. 7 is a diagram showing a configuration of an optical transmission device according to an embodiment of the present invention.

FIG. 8 is a diagram showing a configuration of a modified example of the spectroscopic device according to the embodiment of the present invention.

[Explanation of symbols]

100 ... Temperature measuring device 1 ... Light source device 2 ... Chopper device 3 ... Optical transmission device 4. Spectroscopic device 5 ... Light receiving device 6 ... Chopper device 7 ... Optical transmission device 8 ... Spectroscopic device 9 ... Light receiving device 10 ... Control device 11 ... Measuring object 12 ... Surrounding objects 13 ... Synchrotron radiation 14 ... Synchrotron radiation 15 ... Illumination light 16 ... Reflected light 17 ... Collimating lens 181, 182 ... Half mirror 191, 192, 193 ... Interference filter 201, 202, 203 ... Light 211, 212, 213 ... Condensing lens 221, 222, 223 ... Sensor 23 ... Slit 24 ... Diffraction grating 31 ... Bundled fiber 32 ... lot 33 ... Fiber for illumination 34 ... Fiber for receiving light 51 ... Light source 52 ... Dichroic mirror 53 ... Light source 54 ... Focusing lens

Claims (11)

[Claims] 1. The radiated light and the reflected light of a measuring object are measured at a plurality of wavelengths, the emissivity of the measuring object is calculated from the measurement result of the reflected light, and the emissivity of a surrounding object does not depend on the wavelength. Assuming that the values are known if assumed or dependent, construct an equation from the measurement results at each measurement wavelength, and find the solution that best satisfies this equation to determine the temperature of the measurement object and the temperature of the surrounding object. A method for measuring temperature, which comprises measuring. 2. The temperature measuring method according to claim 1, wherein the emitted light and the reflected light of the measuring object are measured at three kinds of wavelengths. 3. The emitted light and the reflected light of the measurement object are measured at three or more kinds of wavelengths, an equation is constructed from the measurement results at each measurement wavelength, and a group of solutions that most satisfy this equation is obtained. The temperature measuring method according to claim 1, wherein the temperature of the measurement object and the temperature of the surrounding object are measured by extracting a solution having the highest reliability from a group of solutions. 4. A light source for illuminating the measurement object, and an illumination light from the light source for transmitting the illumination light from the light source to the measurement object, the algorithm comprising the algorithm according to any one of claims 1 to 3.
A light transmitting means, a spectroscopic means for splitting a desired wavelength in the emitted light and the reflected light of the measuring object to guide to a plurality of light receiving elements, and a second means for transmitting the emitted light and the reflected light of the measuring object to the spectroscopic means And a light receiving means for amplifying an output from the light receiving element. 5. A first light blocking means for blocking the illumination light from the light source, and a second light blocking means for blocking the emitted light and the reflected light of the measurement object. The temperature measuring device according to 4. 6. The emitted light of the measurement object and the emitted light of the surrounding object are guided to the second light transmitting means by closing the first light shielding means and opening the second light shielding means, and the second light transmitting means is provided. By opening the first light blocking means and opening the second light blocking means, there is provided control means for controlling the emitted light and the reflected light of the measurement object and the emitted light of the surrounding object to be guided to the second light transmitting means. The temperature measuring device according to claim 5, wherein 7. A second spectroscopic unit that disperses a desired wavelength in a part of the illumination light from the light source and guides it to a plurality of light receiving elements, and a part of the illumination light from the light source in the second spectroscopic unit. The temperature measuring device according to claim 4, further comprising: a third light transmitting unit that transmits the light to the second light transmitting unit, and a second light receiving unit that amplifies the output from the light receiving element. 8. The temperature according to claim 4, wherein the light source is pulse-driven, and each of the light receiving means receives the emitted light and the reflected light of the measuring object in synchronization with the pulse timing of the light source. measuring device. 9. The temperature measuring device according to claim 4, wherein each of the spectroscopic means comprises a diffraction grating and guides the diffracted light to a plurality of light receiving elements. 10. A method of manufacturing a semiconductor device, which comprises manufacturing a semiconductor device by using the temperature measuring method according to claim 1. 11. The radiated light and the reflected light of a measuring object are measured at a plurality of wavelengths, the emissivity of the measuring object is calculated from the measurement result of the reflected light, and the emissivity of surrounding objects is independent of the wavelength. Assuming that the values are known if assumed or dependent, construct an equation from the measurement results at each measurement wavelength, and find the solution that best satisfies this equation to determine the temperature of the measurement object and the temperature of the surrounding object. A computer-readable storage medium characterized by storing a program for measuring.