JP2003215028A - Method and apparatus for detecting chemical substance - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for detecting chemical substances and identifying and determining the chemical substances by an infrared multiple internal reflection method capable of easily and highly accurately detecting the chemical substances at low costs. <P>SOLUTION: The chemical substance detecting apparatus comprises an infrared transmitting substrate 10, an infrared light source 20, an infrared detector 32 for detecting infrared rays to be emitted after multiple reflection inside the infrared transmitting substrate 10, a chemical substance analyzing means 30 for computing the amount of adhesion of the chemical substances which have adhered onto the infrared transmitting substrate 10 based on detected infrared rays, a substrate temperature measuring means 60 for measuring the temperature of the infrared transmitting substrate 10, a substrate heating means 74 for heating the infrared transmitting substrate 10, and a substrate temperature control means 76 for controlling the substrate heating means 74 on the basis of the temperature of the infrared transmitting substrate 10 and maintaining the infrared transmitting substrate 10 at an approximately constant temperature. <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 chemical substance detection method and device, and more particularly to a chemical substance detection method and device for identifying and quantifying a chemical substance by an infrared multiple internal reflection method.

[0002]

2. Description of the Related Art It is required in various aspects to identify the type of chemical substance or quantify its concentration. For example, in a semiconductor device manufacturing process, in order to improve the manufacturing yield and manufacture a high quality semiconductor device, it is necessary to measure and control chemical substances such as organic pollutants adhered to a semiconductor substrate in the manufacturing process. is necessary. In addition, environmental pollution caused by chemical substances existing in the atmosphere, for example, trace amounts of chemical substances such as dioxins emitted from garbage incineration facilities, and VOC (volatile organic substances) contained in building materials for new houses and condominiums. : Volatile Org
Health problems caused by chemical substances called anic compond) have become a social problem, and there is an urgent need to measure and manage chemical substances contained in the atmosphere.

As one means for measuring such a chemical substance, the present inventors have already proposed a method of detecting the chemical substance by the infrared multiple internal reflection method (for example, Japanese Patent No. 3261362, International Publication). No. WO01 / 130
93).

The chemical substance detection method disclosed in Japanese Patent No. 3261362 identifies the type of chemical substance adhered on the substrate by analyzing infrared rays emitted after multiple reflection inside the infrared transparent substrate. , To quantify its concentration. When infrared rays are incident on one end of the infrared transparent substrate at a specific incident angle, the infrared rays propagate inside the substrate while repeating total reflection on both surfaces. At that time, infrared rays bleed out to the surface of the substrate (evanescent light), and the infrared rays in a specific wavelength range are absorbed by the chemical substances attached to the surface. Therefore, the spectroscopic analysis of the propagation light emitted from the other end of the substrate by FT-IR makes it possible to detect and identify the chemical substances attached to the substrate surface.

A method for detecting a chemical substance described in International Publication No. WO01 / 13093 is disclosed in JP-A-2000-55.
The chemical substance detection method described in Japanese Patent No. 815 is used to measure the concentration of chemical substances in the atmosphere. After exposing the infrared transparent substrate to the environment of the measurement object, by using this substrate to measure chemical substances by the infrared multiple internal reflection method,
The concentration of the chemical substance in the atmosphere can be calculated from the amount of the chemical substance attached on the substrate.

These measuring methods have the same sensitivity as the GC / MS method and the like, and have real-time measurement, and are simple and economical. Further, this measuring method is a non-destructive measurement, and it is possible to directly measure the semiconductor substrate in the manufacturing process.

[0007]

However, although the above-mentioned conventional chemical substance detection methods are excellent in qualitative analysis ability and quantitative analysis ability, they are disadvantageous in that the apparatus price is expensive and the apparatus volume is large. It is difficult to detect the presence of chemical substances easily, quickly and at low cost, and to feed back the measurement results to environmental management.

Further, in the above conventional chemical substance detection method,
The attached amount of the chemical substance was calculated based on the absorbance of the transmitted infrared rays, but if the infrared ray absorption other than the absorption by the chemical substance was observed, the accurate attached amount could not be obtained.

For example, when the multiple internal reflection substrate is a semiconductor substrate, the amount of free carriers in the substrate changes when the temperature of the substrate changes. Since free carriers absorb infrared rays, the infrared transmittance of the multiple internal reflection substrate changes according to changes in the substrate temperature. When the amount of infrared light transmitted through the substrate changes due to such a factor, in the conventional chemical substance detection method, it is because the change in the amount of light is due to the absorption by the chemical substance adhering to the substrate surface or the temperature change of the substrate. However, it was not possible to calculate the exact amount of chemical substances.

It is an object of the present invention to provide a chemical substance detection method and apparatus capable of detecting a chemical substance attached to a substrate simply, with high accuracy and at low cost.

[0011]

The above-mentioned object is to detect infrared rays emitted from the infrared transmission substrate after the infrared rays are incident on the infrared transmission substrate and are multiple-reflected inside the infrared transmission substrate. In the chemical substance detection method of calculating the amount of the attached chemical substance on the infrared transparent substrate based on the intensity of the infrared rays, in the reference state of the infrared transparent substrate, the infrared transparent substrate is transmitted. The first light amount is measured, and in a state where the amount of the chemical substance on the infrared transmission substrate is changed, at a temperature substantially equal to the temperature of the infrared transmission substrate when the first light amount is measured, The second amount of light transmitted through the infrared transmitting substrate is measured, and the amount of the chemical substance attached on the infrared transmitting substrate is calculated in consideration of the first amount of light and the second amount of light. Chemical substance detection method characterized by It is achieved by.

Further, in the above chemical substance detection method,
When measuring the first light amount and the second light amount,
By measuring the temperature of the infrared transparent substrate and comparing the signal based on the measured temperature of the infrared transparent substrate and the signal based on a predetermined reference temperature, the temperature of the infrared transparent substrate is almost equal to the reference temperature. You may make it maintain an equal temperature.

Further, the above object is to detect the infrared rays emitted from the infrared transmitting substrate after the infrared rays are incident on the infrared transmitting substrate and are multiple-reflected inside the infrared transmitting substrate, and the intensity of the detected infrared rays is detected. In the chemical substance detection method for calculating the amount of attachment of the chemical substance adhered on the infrared transparent substrate based on, the temperature dependence of the infrared transmittance of the infrared transparent substrate is measured, In the standard state of the substrate, the first amount of light transmitted through the infrared transmissive substrate and the temperature of the infrared transmissive substrate are measured, and when the amount of the chemical substance on the infrared transmissive substrate changes, the red The infrared transmission is performed by measuring the second amount of light transmitted through the outer transmission substrate and the temperature of the infrared transmission substrate, and considering the temperature dependence of the first amount of light, the second amount of light and the transmittance. Applying the above chemical substances on the substrate Also achieved by a chemical substance detection method characterized by calculating the amount.

Further, in the above chemical substance detection method,
In the measurement of the first light amount and the second light amount, infrared rays in a wavelength range where infrared absorption is caused by the chemical substance may be selectively detected.

[0015] Further, the above object is to provide an infrared transmitting substrate, an infrared light source for injecting infrared rays into the infrared transmitting substrate, multiple reflection inside the infrared transmitting substrate, and then emission from the infrared transmitting substrate. Detecting infrared rays, a chemical substance analyzing means for calculating the amount of attached chemical substances on the infrared transmitting substrate based on the detected infrared rays, a substrate temperature measuring means for measuring the temperature of the infrared transmitting substrate, and Substrate temperature control means for changing the temperature of the infrared transmissive substrate, controlling the substrate temperature control means based on the temperature of the infrared transmissive substrate measured by the substrate temperature measuring means, the temperature of the infrared transmissive substrate And a substrate temperature stabilizing means for keeping the temperature substantially constant.

Further, in the above chemical substance detection device,
The substrate temperature control means may be means for blowing a gas having a predetermined temperature onto the infrared transparent substrate.

Further, in the above chemical substance detection device,
The substrate temperature control means may be a constant temperature bath containing the infrared transparent substrate.

Further, in the above chemical substance detection device,
The substrate temperature control means may include a container that encloses the infrared transparent substrate, and a gas introduction device that introduces a gas at a predetermined temperature into the container.

Further, in the above chemical substance detection device,
The substrate temperature stabilizing means compares the signal based on the measured temperature of the infrared transparent substrate measured by the substrate temperature measuring means with a signal based on a predetermined reference temperature,
The temperature of the infrared transparent substrate may be maintained at a temperature substantially equal to the reference temperature.

Further, in the above chemical substance detection device,
In the reference state of the infrared transmission substrate, the chemical substance detection means measures a first amount of light transmitted through the infrared transmission substrate, and in a state where the amount of the chemical substance on the infrared transmission substrate changes. , Measuring a second amount of light transmitted through the infrared transmitting substrate, and considering the first amount of light and the second amount of light,
A means for calculating an adhesion amount of the chemical substance adhered on the infrared transmitting substrate, wherein the substrate temperature stabilizing means is a temperature of the infrared transmitting substrate when measuring the first light amount,
The temperature of the infrared transmissive substrate may be controlled so that the temperature of the infrared transmissive substrate at the time of measuring the second light amount becomes substantially equal.

[0021] Further, the above-mentioned object is to provide an infrared transmitting substrate, an infrared light source for making infrared rays incident on the infrared transmitting substrate, a substrate temperature measuring means for measuring the temperature of the infrared transmitting substrate, and the infrared transmitting substrate. Infrared detecting means for detecting infrared rays emitted from the infrared transmitting substrate after multiple reflections inside the substrate, infrared rays detected by the infrared detecting means and temperature of the infrared transmitting substrate measured by the substrate temperature measuring means And a chemical substance analysis means for calculating the attached amount of the chemical substance attached to the infrared transparent substrate based on the above.

Further, in the above chemical substance detection device,
The chemical substance detection means may selectively detect infrared rays in a wavelength range corresponding to a specific molecular vibration, and calculate the amount of the chemical substance attached based on the absorbance of the infrared rays in the wavelength range.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [Principle of the Present Invention] The principle of the present invention will be described with reference to FIGS.

FIG. 1 is a schematic diagram showing an example of a chemical substance detection system in a chemical substance detection device according to the present invention, and FIG. 2 is a graph showing an example of an infrared transmission spectrum of a band pass filter.
3 is a schematic diagram showing an example of a substrate temperature control system in the chemical substance detection device according to the present invention, FIG. 4 is a graph showing the relationship between the absorbance and the residual carbon deposited on the substrate, and FIG. 5 is the chemistry deposited on the substrate. It is a graph which shows the relationship between the adhesion amount of a substance and the concentration of a chemical substance in the atmosphere.

The chemical substance detection device according to the present invention has a chemical substance detection system for detecting a chemical substance by the infrared multiple internal reflection method, and a substrate temperature control system for detecting and controlling the temperature of the substrate. Hereinafter, these will be described individually.

[1] Chemical Substance Detection System An example of the chemical substance detection system in the chemical substance detection device according to the present invention will be described with reference to FIG.

An infrared light source 20 is provided on one end surface side of the infrared transmissive substrate 10 for injecting infrared rays into the infrared transmissive substrate 10 for internal multiple reflection. Infrared transparent substrate 10
On the other end surface side of the infrared ray transmitting substrate 10, multiple infrared rays emitted after multiple reflection inside the infrared ray transmitting substrate 10 are detected, and chemical substances attached to the infrared ray transmitting substrate 10 are analyzed based on the detected infrared rays. Means 30 are provided.

The chemical substance detecting means 30 detects an infrared ray transmitted through the infrared transparent substrate and converts the infrared signal into an electric signal, and an electric signal outputted from the infrared detector 32 is converted into a digital signal A. A / D converter 34, and an arithmetic unit 36 for calculating the amount of chemical substances attached to the infrared transparent substrate 10 based on the output signals from the A / D converter 34.
And the database 3 referenced when quantifying chemical substances
8 and.

A chopper 40 is provided between the infrared transmitting substrate 10 and the infrared detector 32, and the infrared detector 32 and the A / D converter 3 are provided.
A lock-in amplifier 42 is provided between the
A chopper drive circuit 44 is connected to the chopper 40 and the lock-in amplifier 42, and the chopper drive circuit 44 causes the chopper 40 to perform a chopping frequency and the infrared detector 3.
It is possible to synchronize the detection of the infrared rays by the 2 above.

Between the infrared transmitting substrate 10 and the infrared detector 32, a band transmitting filter 50 which selectively transmits infrared rays in a predetermined band is provided.

By configuring the chemical substance detection system in this manner, it is possible to measure the chemical substance in real time with high sensitivity using the infrared multiple internal reflection method. Further, since an infrared band transmission filter is provided and only infrared rays in the wavelength region corresponding to the molecular vibration wavelength of the specific chemical substance are detected, it is not necessary to use an expensive FT-IR device. As a result, the device price can be reduced.

Hereinafter, each component of the chemical substance detection system in the chemical substance detection device according to the present invention will be described in detail.

(A) Infrared Transmission Substrate 10 The infrared transmission substrate 10 is a substrate to be measured (for example, a semiconductor substrate), or a substrate for adsorbing a chemical substance in an atmosphere to be measured and used for the measurement. Therefore, the material needs to be a material that transmits light in a wavelength range corresponding to the molecular vibration of the chemical substance to be measured. The wavenumber range corresponding to the fundamental vibration of organic substances, which are typical chemical substances, is 500 cm.
^-1 (wavelength 20 μm) to 5000 cm ⁻¹ (wavelength 2 μm) in the infrared / near infrared region. Therefore, the material forming the infrared transmissive substrate 10 is selected from the group of infrared transmissive substances capable of transmitting light in these wave number ranges (wavelength ranges).

As a material that transmits light in the infrared / near infrared region
Is, for example, silicon (Si: transmission wavelength range: 1.2 to 6)
μm), potassium bromide (KBr: transmission wavelength range 0.4 to 2)
2 μm), potassium chloride (KCl: transmission wavelength range 0.3 to
15 μm), zinc selenide (ZnSe: transmission wavelength range 0.
6 to 13 μm), barium fluoride (BaF₂: Transmission wavelength
Area 0.2-5 μm), cesium bromide (CsBr: transmitted wave)
Long range 0.5 to 30 μm, germanium (Ge: transmitted wave)
Long range 2-18 μm, lithium fluoride (LiF: transmitted wave)
Long range 0.2-5 μm), calcium fluoride (CaF₂:
Transmission wavelength range 0.2-8 μm), sapphire (Al₂O₃:
Transmission wavelength range 0.3-5 μm), cesium iodide (Cs
I: transmission wavelength range 0.5 to 28 μm), magnesium fluoride
Mu (MgF ₂: Transmission wavelength range 0.2 to 6 μm), Tungsten bromide
Um (KRS-5: transmission wavelength range 0.6 to 28 μm), sulfur
Zinc oxide (ZnS: transmission wavelength range 0.7 to 11 μm)
is there. Therefore, the infrared transparent substrate 10 is made of these materials.
Can be configured. In addition, among these materials,
Some have deliquescence and may not be suitable depending on the usage environment.
It The material forming the infrared transmissive substrate 10 depends on the operating environment and the necessity.
It is desirable to select appropriately according to the required transmission wavelength range.

The outer shape of the infrared transmitting substrate 10 is, for example, as described in the specification of Japanese Patent Application No. 2000-367291.
It is possible to apply a strip shape in which the end face is tapered to 45 °. Also, for example, International Publication No. WO01 /
A substrate having a plurality of infrared ray propagation lengths as described in Japanese Patent No. 13093 may be applied. Also, for example, Patent No. 3
As described in Japanese Patent No. 261,362, a 300 mm silicon wafer can be used as it is.

(B) Infrared light source 20 As the infrared light source 20, a light source that emits infrared rays in the 2 to 25 μm band corresponding to the molecular vibration of organic molecules can be applied.

For example, a silicon carbide (SiC) as a filament or a heat ray generated by applying a current to a nichrome wire can be used as a light source. A light source using SiC such as a SiC global light emits infrared rays in a band of 1.1 to 25 μm, and has a feature that it does not burn even if it is exposed in air.

A semiconductor laser or a light emitting diode having an emission wavelength in the infrared / near infrared region can also be used as the infrared light source. A light source using a semiconductor laser or a light emitting diode is characterized in that it is small and that a small focal point is easily focused on the end face of the substrate.

Further, a reflector having an appropriate shape may be provided to enhance the efficiency of the light source and increase the intensity of infrared rays.
For example, various infrared light sources described in Japanese Patent No. 3261362 can be applied.

(C) Band Transmission Filter 50 The band transmission filter 50 is a filter that selectively transmits infrared rays in a predetermined band, and has a functional group (for example, CH group, etc.) peculiar to the chemical substance to be measured. O-H group, Si-H
It transmits infrared rays in the wavelength range corresponding to the molecular vibration of the base). For example, when measuring a chemical substance that exhibits infrared absorption due to C—H stretching vibration, for example, a wave number of 2800 to 3000 c
A filter having a transmission band near m ^-1 is used.

An infrared band pass filter corresponding to the molecular vibration wavelength of a specific functional group is, for example, Spectrogon (SP of the United States).
It is sold by ECTROGON). FIG. 2 is a graph showing an example of an infrared transmission spectrum of an infrared band transmission filter sold by the same company. 2 (a), 2 (b),
FIG. 2C shows a filter transmitting a wavelength range corresponding to the molecular vibration of the O—H group, a filter transmitting a wavelength range corresponding to the molecular vibration of the C—H group, and a molecular vibration of the Si—H group, respectively. Is a filter that transmits a wavelength range corresponding to. Such a filter can be applied to the bandpass filter 50 of the chemical substance detection apparatus according to the present embodiment.

It is necessary to provide an expensive infrared interferometer by providing a band-pass filter 50 and selectively detecting infrared rays in a wavelength range corresponding to molecular vibration of a functional group peculiar to a chemical substance to be measured. Since it does not exist, the price of the device can be reduced.

The band-pass filter 50 may be provided between the infrared transmission substrate 10 and the infrared detector 32, or may be provided between the infrared transmission substrate 10 and the infrared light source 20. .

(D) Chemical substance analyzing means 30 As shown in FIG. 1, the chemical substance analyzing means 30 includes an infrared detector 32 for detecting infrared rays transmitted through the infrared transmitting substrate and converting the infrared rays into an electric signal. An A / D converter 34 for converting the electric signal output from the infrared detector 32 into a digital signal;
A calculation device 36 for calculating the attached amount of the chemical substance attached to the infrared transmission substrate 10 based on the output signal from the / D converter 34, and a database 38 referred to when quantifying the chemical substance are provided. is doing.

The infrared rays emitted from the infrared transparent substrate 10 pass through the band pass filter 50 and then enter the chemical substance detecting means 30. If the filter of the infrared transmission filter 50 is set to a filter that transmits the wavelength range corresponding to the molecular vibration of the functional group peculiar to the chemical substance to be measured, the intensity of the infrared rays detected by the infrared detector 32. Indicates the amount of the chemical substance attached to the infrared transparent substrate 10. Therefore, by comparing the intensity of infrared rays detected by the infrared detector 32 with a predetermined reference amount, it is possible to calculate the attached amount of the chemical substance on the infrared transparent substrate 10.

The types of chemical substances and the calibration curve are separately stored in the database 38, and the measurement data are quantified by referring to those data. Further, the database 38 stores a relation between the amount of the chemical substance adsorbed on the surface of the infrared transmitting substrate 10 and the amount of the chemical substance in the atmosphere as a database, and the detected surface of the infrared transmitting substrate 10 is detected. It is also possible to calculate the concentration of chemical substances in the atmosphere from the amount of chemical substances. The method for quantifying the amount and concentration of chemical substances will be described later.

A display device (not shown) may be provided so as to be connected to the arithmetic unit 36 to display the analysis result of the arithmetic unit 36.

In the chemical substance detecting apparatus according to the present embodiment, the chopper 40 is provided between the infrared transparent substrate 10 and the infrared detector 32 so that the chopper driving circuit 44 drives the infrared detector 32. A lock-in amplifier 42 is provided between the A / D converter 34 and the A / D converter 34. The S / N ratio can be improved by synchronizing the chopping frequency of the chopper 40 and the detection of infrared rays. The chopper 40, the chopper drive circuit 44, the lock-in amplifier 42
Need not necessarily be provided.

[2] Substrate Temperature Control System By using the above-mentioned chemical substance detection system, the presence of a chemical substance can be detected simply, quickly and at low cost. However, in the above-mentioned chemical substance detection method, since the attached amount of the chemical substance is calculated based on the absorbance of the infrared ray that has passed through the infrared transparent substrate, if the infrared ray absorption other than the chemical substance absorption occurs, It was not possible to obtain a sufficient adhesion amount.

For example, when the multiple internal reflection substrate is a semiconductor wafer, the amount of free carriers in the substrate changes when the temperature of the substrate changes. Since free carriers absorb infrared rays, the infrared transmittance of the multiple internal reflection substrate changes according to changes in the substrate temperature. When the amount of infrared light transmitted through the substrate changes due to such factors, it is impossible to distinguish whether the change in the amount of light is due to absorption by the chemical substances adhering to the substrate surface or due to the temperature change of the substrate. , It was not possible to calculate the exact amount of chemical substances.

Therefore, in the chemical substance detecting device according to the present invention, a substrate temperature control system as shown in FIG. 3 is further provided in order to solve such a problem. That is, in the chemical substance detection method according to the present invention, the substrate temperature measuring means 60 for measuring the temperature of the infrared transmitting substrate 10 and the infrared transmitting based on the temperature of the infrared transmitting substrate 10 measured by the substrate temperature measuring means 60 are used. Substrate temperature control means 70 for controlling the temperature of the substrate 10 is provided.

The substrate temperature control means 70 includes a temperature signal 1 which is a signal output from the substrate temperature measuring means 60 and which is a signal relating to the actually measured temperature of the infrared transparent substrate 10, and a temperature which is a signal relating to a reference temperature which is set as the measurement temperature. The signal 2 is input, and the substrate temperature control mechanism is feedback-controlled based on these signals to keep the temperature of the infrared transparent substrate 10 near the reference temperature.

By thus maintaining the temperature of the infrared transmitting substrate 10 at a substantially constant temperature during the measurement, it is possible to prevent the change of the absorbance due to the temperature change of the infrared transmitting substrate 10 and to obtain a more accurate chemical substance. Can be measured. For highly accurate measurement, it is desirable to keep the temperature of the infrared transmission substrate 10 within ± 3 ° C. of the reference temperature.

As the substrate temperature measuring means 60, a known temperature measuring means using a thermocouple or other temperature measuring element can be used.

As means for changing the temperature of the infrared transparent substrate 10 in the substrate temperature control means, a method using heat conduction, a method using heat radiation, a method using heat convection, heating / cooling of the substrate itself. There is a way to do it.

As a method of using heat conduction, an element capable of changing the temperature, for example, a Peltier element or a heater is brought into close contact with the infrared transparent substrate 10 and the heat of the element is conducted to the infrared transparent substrate 10 to control the temperature. The method of doing is mentioned.

As a method of using thermal radiation, a method of placing a thermal radiator near the infrared transmissive substrate 10 and heating the infrared transmissive substrate 10 can be mentioned. In this case, heating in vacuum is also possible.

As a method of using thermal convection, there is a method of controlling the temperature of the infrared transmitting substrate 10 by providing a cooler in the upper part of the constant temperature bath and a heater in the lower part of the constant temperature bath to convect the air in the constant temperature bath. .

As the method of self-heating / cooling, a method of applying a fluctuating magnetic field to the infrared transmissive substrate 10 to heat the infrared transmissive substrate 10 in a non-contact manner (induction heating / eddy current heating / high frequency heating), or a red method A method of electrically heating the outer transparent substrate 10 may be considered.

As more specific means, a gas whose temperature is controlled to a predetermined temperature is blown onto the infrared transparent substrate 10, the infrared transparent substrate 10 is placed in a constant temperature bath, or a gas whose temperature is controlled to a predetermined temperature. There is a means for introducing into the container in which the infrared transparent substrate 10 is placed.

It should be noted that instead of performing the measurement in the reference state and the measurement in the state where the chemical substance is attached at substantially the same temperature, the infrared transmission substrate 10 in the measurement in the reference state is used.
And the temperature of the infrared transmissive substrate 10 at the time of measurement in the state where the chemical substance is adhered, and considering the temperature dependence of the infrared transmissivity of the infrared transmissive substrate 10 measured in advance. Alternatively, the measurement value of the light amount may be corrected, and the chemical substance may be quantified based on the correction value. That is, the first amount of light measured in the reference state was converted into a numerical value, the correction value of the first amount of light at the reference temperature was calculated from the temperature dependence of the transmittance of the infrared transparent substrate, and the measurement was performed in the state where the chemical substance was attached. The second light amount is digitized, the second light amount correction value at the reference temperature is calculated from the temperature dependence of the transmittance of the infrared transmitting substrate, and the first light amount correction value and the second light amount correction value are calculated. From the ratio, the chemical substance can be quantified by the chemical substance quantification method described later.

[3] Quantification of Chemical Substance In the method for detecting a chemical substance according to the present invention, the infrared transparent substrate 10 is used.
The amount of the chemical substance attached to the infrared transmissive substrate 10 is calculated based on the infrared absorbance of the chemical substance attached to or present in the vicinity of the infrared transmission substrate 10. Alternatively, the infrared transparent substrate 10 is based on the amount of attached chemical substance calculated in this way.
Converted to the concentration of chemical substances in the atmosphere where is exposed.

Let C be the concentration of the chemical substance in the atmosphere to which the infrared transmission substrate 10 is exposed, K _{1 be} the conversion coefficient of the attachment amount and the concentration, and W be the attachment amount of the contaminant to the infrared transmission substrate 12. , And the following relational expressions hold between them.

C = K ₁ × W (1) On the other hand, the transmitted light amount I after the infrared transparent substrate 10 is contaminated
Is the transmitted light intensity before contamination I _0, the absorption coefficient per unit deposition amount when the internal number of reflections N, 1 single reflection occurs α
Then, it can be expressed by the following equation.

I = I ₀ × exp (−W × N × α) (2) Further, the absorbance A is expressed as A = −log ₁₀ (I / I ₀ ) ... (3). Therefore, using the expressions (2) and (3), the absorbance A can be rewritten as the following expression.

A ∝ W × N × α (4) Therefore, in the equation (1), the conversion coefficient between the absorbance and the concentration is K
_{If it is 2} , it can be rewritten as the following equation.

C = K ₂ × A (5) From equations (1) and (5), a proportional relationship is established between the concentration of the chemical substance and the amount of the substance attached to the substrate, and the concentration of the chemical substance and the absorbance. I understand that Therefore, the amount of the chemical substance adhering to the infrared transparent substrate 10 can be obtained from the magnitude of the absorbance, and further, by multiplying this by the conversion coefficient,
The concentration of the chemical substance in the atmosphere to which the infrared transparent substrate 10 is exposed can be calculated.

The conversion coefficient can be measured, for example, by the following procedure.

First, the infrared transmissive substrate 12 is exposed to the space where the pollutant exists at a constant concentration.

Next, the concentration of the pollutant in the gas is measured by another means (gas detector tube, gas chromatograph, etc.).

Next, the magnitude of the absorption peak of the absorption peak due to the contaminant attached to the infrared transmission substrate 12 is measured by the internal multiple reflection method.

Next, the above steps 1 to 3 are repeated for a plurality of pollutant concentration spaces, and the conversion coefficient is obtained from the ratio of the results of.

It is desirable that the exposure time of the substrate is constant. This is because if the exposure time is different, the adhered amount may change even if the concentration of the pollutant is the same, and in this case, it is necessary to convert the magnitude of the absorbance so that the exposure time becomes equal. For this purpose, it is necessary to measure the magnitude of the absorbance at appropriate intervals while exposing the infrared transmissive substrate 12 to the atmosphere, and to obtain the relationship between the exposure time and the magnitude of the absorbance in advance.

Further, for accurate measurement, it is necessary that the internal reflection conditions are equal, and it is necessary to make infrared rays incident on the same substrate or substrates of the same shape under the same conditions. Further, since the extinction coefficient differs depending on the type of contaminant, it is necessary to measure the conversion coefficient in advance for all the substances to be measured in order to perform accurate quantitative measurement.

When calculating the adhered amount per unit area on the substrate, a calibration curve is prepared in advance by the following procedure.

First, a plurality of solutions having different concentrations are prepared by diluting contaminants in a volatile solvent.

Next, a fixed amount of this solution is applied onto the substrate.

Next, the substrate coated with the solution is left for an appropriate time to evaporate the solvent.

Then, the magnitude of the absorption peak of the absorption peak due to the contamination attached to the substrate is measured by the internal multiple reflection method.

Next, the amount of adhered contaminants per unit area is calculated from the concentration of the solution, the coating amount, and the substrate area.

Next, a calibration curve is created from the relationship between the adhered amount and the absorbance.

In this way, the absolute amount of contaminants adhering to the substrate can be determined from the comparison between the calibration curve and the absorbance obtained by exposing the substrate to the atmosphere.

FIG. 4 is a calibration curve showing the relationship between the absorbance and the residual carbon amount, which was prepared using a sample in which DOP diluted with ethanol was uniformly coated on a 300 mm silicon wafer. In the case of the calibration curve shown in FIG. 4, when the infrared absorbance is 0.01, the residual carbon amount on the infrared transparent substrate is 1 × 1.
It is shown that it is 0 ¹⁵ cm ^-2 .

By previously preparing a calibration curve as shown in FIG. 4 and storing it in the database 38, it is possible to calculate the adhesion amount of the chemical substance adhered on the infrared transparent substrate 10 from the absorbance of infrared rays.

FIG. 5 is a graph showing the relationship between the concentration of chemical pollutants in the air and the surface contamination of a silicon wafer as an infrared transparent substrate after being left for 24 hours. In the case of DOP (dioctyl phthalate), for example, 1 ng / m ³ DOP
It is shown that when the wafer is left for 24 hours in a concentrated atmosphere, the amount of adhesion to the wafer surface is 10 ¹² CH ₂ unit / cm ² . Conversely, if the amount of adhesion on the wafer surface after standing for 24 hours is 10 ¹² CH ₂ unit / cm ^2, it can be seen that the DOP concentration in the atmosphere is 1 ng / m ³ . On the other hand, as shown in the case of TBP (tributyl phosphate: flame retardant) and siloxane (volatile substance from silicone caulking agent), the relationship between the concentration in air and the adhered amount depends on conditions such as pollutants and leaving time. different. Therefore, it is necessary to previously obtain the relationship between the concentration in air and the amount of adhered substances for each substance to be measured.

By preparing a calibration curve as shown in FIG. 5 in advance and storing it in the database 38, the infrared transmitting substrate 10
The concentration of the chemical substance existing in the atmosphere can be calculated from the chemical mass attached to the top. Further, instead of the calibration curve shown in FIG. 5, a calibration curve showing the relationship between the concentration of the chemical substance in the atmosphere and the magnitude of the absorbance of the absorption peak is created in advance and stored in the database 38, and the contamination existing in the atmosphere is stored. The concentration of the substance may be calculated.

[A First Embodiment] The chemical substance detecting method and apparatus according to a first embodiment of the present invention will be explained with reference to FIG.

FIG. 6 is a schematic view showing the structure of the chemical substance detecting apparatus according to the present embodiment.

First, the structure of the chemical substance detecting apparatus according to the present embodiment will be explained with reference to FIG.

An infrared light source 20 is provided near the edge of the semiconductor wafer as the infrared transparent substrate 10. An infrared detector 32 is provided in the vicinity of the end of the semiconductor wafer facing the end where the infrared light source 20 is provided via a band pass filter 50. Thus, the chemical substance detection system shown in FIG. 1 is constructed.

An air duct 72 for taking in gas and blowing it onto the infrared transparent substrate 10 is provided near the infrared transparent substrate 10. The heater 7 is installed in the air duct 72.
4 is provided so that the gas passing through the air duct 72 can be heated. A heater heating power supply 76 that controls the temperature of the heater 74 is connected to the heater 74. Substrate temperature measuring means 60 for measuring the temperature of the infrared transmission substrate 10 is also provided in the vicinity of the infrared transmission substrate 10. To the heater heating power supply 76, a temperature signal that is a signal related to the actually measured temperature of the infrared transparent substrate 10 output from the substrate temperature measuring means 60 and a temperature signal that is a signal related to a reference temperature set as a measurement temperature are input. ,
Based on these signals, the heater heating power supply 76 is feedback-controlled to maintain the temperature of the infrared transparent substrate 10 at the reference temperature. Thus, the substrate temperature control system shown in FIG. 3 is constructed.

Next, the chemical substance detection method according to the present embodiment will be explained with reference to FIG.

First, before the measurement of the substrate to be measured, the measurement in the reference state is performed. The measurement in the reference state may be performed each time the measurement target substrate is measured, or may be performed periodically (for example, each time a predetermined number of substrates are processed).

First, the infrared transparent substrate 1 as a standard substrate having no chemical substance attached on the surface such as a substrate immediately after cleaning.
0 is installed in the chemical substance detection device.

Next, the heater heating power supply 76 heats the gas introduced from the air duct 72. This allows
The heated gas is blown onto the infrared transmissive substrate 10 to raise the temperature of the infrared transmissive substrate 10 to a predetermined temperature set as a reference temperature. The temperature of the infrared transparent substrate 10 is maintained at a constant temperature by controlling the heater heating power supply 76.

Next, the infrared rays emitted from the infrared light source 20 are made incident on the infrared transmission substrate 10. Infrared transparent substrate 10
The infrared rays incident on the substrate undergo multiple internal reflection on the front and back surfaces of the substrate, and then are emitted to the outside of the substrate.

Next, the infrared rays emitted from the infrared transmission substrate 10 are passed through the band-pass filter 50 to the infrared detector 3
It detects by 2. The detected amount of infrared light is stored in the database 38.

Thus, the measurement in the standard state is completed.

Next, the substrate to be measured is measured.

First, the infrared transparent substrate 1 as the substrate to be measured.
0 is installed in the chemical substance detection device.

Then, similarly to the case of the measurement in the reference state, the temperature of the infrared transmitting substrate 10 is raised to the same reference temperature as that set in the case of the measurement in the standard state,
Hold at a constant temperature. When measuring the chemical substance in the atmosphere, the gas to be measured may be used as the gas taken in from the air duct 72.
By doing so, not only the amount of the chemical substance attached to the infrared transparent substrate 10 can be measured but also the concentration of the chemical substance in the atmosphere can be measured.

Then, the infrared rays emitted from the infrared light source 20 are made incident on the infrared transparent substrate 10. Infrared transparent substrate 1
The infrared rays incident on the inside of the infrared ray 0 are multiply internally reflected on the front and back surfaces of the infrared transparent substrate 10, and at the same time, the information of the chemical substances adsorbed on the surface of the infrared transparent substrate 10 is accumulated and probing is performed. It is emitted to the outside of the outer transparent substrate 10.

Next, the infrared rays emitted from the infrared transmitting substrate 10 are passed through the band-pass filter 50 to the infrared detector 3
It detects by 2. The detected amount of infrared light is stored in the database 38.

Thus, the measurement of the substrate to be measured is completed.

Next, the absorbance is calculated with reference to the light amount in the reference state accumulated in the database 38 and the light amount obtained from the substrate to be measured.

Next, referring to a predetermined calibration curve stored in the database 38, the attached amount of the chemical substance attached to the infrared transmitting substrate 10 is calculated. If applicable, the concentration of the chemical substance in the atmosphere is calculated by referring to the predetermined calibration curve stored in the database 38.

As described above, according to this embodiment, it is possible to suppress the change in the amount of transmitted light due to the temperature change of the infrared transmitting substrate, so that the change in the amount of transmitted light due to the chemical substance attached on the infrared transmitting substrate can be suppressed. It can be measured more accurately.
Therefore, the detection sensitivity of chemical substances can be improved.

[A Second Embodiment] The chemical substance detecting method and apparatus according to a second embodiment of the present invention will be explained with reference to FIG.

FIG. 7 is a schematic view and a plan view showing the structure of the chemical substance detecting device according to the present embodiment. Note that FIG.
FIG. 7A is a schematic view of the chemical substance detection device according to the present embodiment, and FIG. 7B is a schematic view of the chemical substance detection device according to the present embodiment seen from above.

First, the structure of the chemical substance detecting apparatus according to the present embodiment will be explained with reference to FIG.

The semiconductor wafer as the infrared transparent substrate 10 is placed in the constant temperature bath 78. In the constant temperature bath 78,
A constant temperature bath temperature controller 80 is connected so that the temperature of the constant temperature bath 78 can be controlled. Constant temperature bath 78
Further, there is provided a substrate temperature measuring means 60 for measuring the temperature of the infrared transparent substrate 10. A temperature signal which is a signal relating to the actually measured temperature of the infrared transparent substrate 10 output from the substrate temperature measuring means 60 and a temperature signal which is a signal relating to a reference temperature set as a measurement temperature are input to the constant temperature bath temperature controller 80. Based on these signals, the constant temperature bath temperature controller 80 is feedback-controlled to maintain the temperature of the infrared transparent substrate 10 at the reference temperature. Thus, the substrate temperature control system shown in FIG. 3 is constructed.

The constant temperature bath 78 is also provided with infrared light transmitting windows 82 and 84 for transmitting infrared rays.
Infrared rays are incident on the infrared transparent substrate 10 from the outside, and the infrared rays emitted from the infrared transparent substrate 10 can be taken out of the constant temperature bath 78.

The infrared light source 20 is provided outside the constant temperature bath 78 near the end of the infrared transparent substrate 10 through an infrared light transparent window 82. In the vicinity of the end of the infrared transmitting substrate 10 facing the end where the infrared light source 20 is provided, an infrared light transmitting window 84,
The infrared detector 32 is provided via the detection optical system 46 and the band-pass filter 50. Thus, the chemical substance detection system shown in FIG. 1 is constructed.

Next, the chemical substance detecting method according to the present embodiment will be explained with reference to FIG.

First, prior to the measurement of the substrate to be measured, the measurement in the reference state is performed. The measurement in the reference state may be performed each time the measurement target substrate is measured, or may be performed periodically (for example, each time a predetermined number of substrates are processed).

First, an infrared transmitting substrate 1 as a standard substrate having no chemical substance attached on the surface thereof, such as a substrate immediately after cleaning.
0 is installed in the constant temperature bath 78.

Next, the constant temperature bath temperature controller 80 raises the temperature of the infrared transparent substrate 10 to a predetermined temperature set as a reference temperature. The temperature of the infrared transparent substrate 10 is
A constant temperature is maintained by controlling the constant temperature bath temperature controller 80.

Next, the infrared rays emitted from the infrared light source 20 are made incident on the infrared transmission substrate 10 through the infrared transmission window 82. The infrared rays incident on the infrared transparent substrate 10 undergo multiple internal reflection on the front and back surfaces of the substrate, and then are emitted to the outside of the substrate.

Next, the infrared rays emitted from the infrared transmission substrate 10 are detected by the infrared detector 32 through the infrared light transmission window 84, the detection optical system 46 and the band transmission filter 50. The detected amount of infrared light is stored in the database 38.

Thus, the measurement in the standard state is completed.

Next, the substrate to be measured is measured.

First, the infrared transparent substrate 10 which is the substrate to be measured.
Are installed in a constant temperature bath 78.

Next, the temperature of the infrared transmitting substrate 10 is raised to the same temperature as that set in the case of the measurement in the standard state by the constant temperature bath temperature controller 80 and kept at a constant temperature.

Next, the infrared rays emitted from the infrared light source 20 are made incident on the infrared transmission substrate 10 through the infrared transmission window 82. The infrared rays that have entered the infrared transmission substrate 10 are multiply internally reflected on the front and back surfaces of the infrared transmission substrate 10 and at the same time accumulate information on chemical substances adsorbed on the surface of the infrared transmission substrate 10. Probing and infrared transparent substrate 1
It is released to the outside of 0.

Next, the infrared rays emitted from the infrared transmission substrate 10 are detected by the infrared detector 32 through the infrared light transmission window 84, the detection optical system 46 and the band transmission filter 50. The detected amount of infrared light is stored in the database 38.

Thus, the measurement of the substrate to be measured is completed.

Then, the absorbance is calculated with reference to the light amount in the reference state accumulated in the database 38 and the light amount obtained from the substrate to be measured.

Next, referring to a predetermined calibration curve stored in the database 38, the attached amount of the chemical substance attached to the infrared transparent substrate 10 is calculated.

As described above, according to this embodiment, it is possible to suppress the change in the amount of transmitted light due to the temperature change of the infrared transmitting substrate, so that the change in the amount of transmitted light due to the chemical substance attached to the infrared transmitting substrate can be suppressed. It can be measured more accurately.
Therefore, the detection sensitivity of chemical substances can be improved.

[A Third Embodiment] The chemical substance detecting method and apparatus according to a third embodiment of the present invention will be explained with reference to FIG.

FIG. 8 is a schematic view and a plan view showing the structure of the chemical substance detecting device according to the present embodiment. Note that FIG.
FIG. 8A is a schematic view of the chemical substance detection device according to the present embodiment, and FIG. 8B is a schematic view of the chemical substance detection device according to the present embodiment as viewed from above.

First, the structure of the chemical substance detecting apparatus according to the present embodiment will be explained with reference to FIG.

The semiconductor wafer as the infrared transparent substrate 10 is placed in the container 86. An air duct 72 is connected to the container 86, and gas can be introduced into the container 86 via the air duct 72. Windows 88, 90 are provided near the end of the infrared transmission substrate 10 of the container 86.
Is provided, and a part of the infrared transmission substrate 10 is exposed to the outside of the container 86. The windows 88 and 90 also allow the gas introduced from the air duct 72 to enter the container 86.
It also plays a role as an exhaust port that discharges to the outside. A heater 74 is provided in the air duct 72, and the air duct 72
The gas passing through it can be heated. A heater heating power supply 76 that controls the temperature of the heater 74 is connected to the heater 74. Further, in the container 86, the substrate temperature measuring means 60 for measuring the temperature of the infrared transparent substrate 10 is provided.
Is provided. To the heater heating power supply 76, a temperature signal that is a signal related to the actually measured temperature of the infrared transparent substrate 10 output from the substrate temperature measuring means 60 and a temperature signal that is a signal related to a reference temperature set as a measurement temperature are input. Based on these signals, the heater heating power supply 76 is feedback-controlled to maintain the temperature of the infrared transparent substrate 10 at the reference temperature. Thus, the substrate temperature control system shown in FIG. 3 is constructed.

The infrared light source 20 is provided near the end of the infrared transmission substrate 10 exposed from the window 88 of the container 86 via the band-pass filter 50 and the incident optical system 48. An infrared detector 32 is provided via a detection optical system 46 near the end of the semiconductor wafer opposite to the end where the infrared light source 20 is provided. Thus, the chemical substance detection system shown in FIG. 1 is constructed.

Next, the chemical substance detecting method according to the present embodiment will be explained with reference to FIG.

First, prior to the measurement of the substrate to be measured, the measurement in the reference state is performed. The measurement in the reference state may be performed each time the measurement target substrate is measured, or may be performed periodically (for example, each time a predetermined number of substrates are processed).

First, the infrared transparent substrate 1 as a standard substrate on the surface of which a chemical substance has not adhered, such as a substrate immediately after cleaning.
0 is installed in the container 86.

Next, the heater heating power supply 76 heats the gas introduced from the air duct 72. This allows
The inside of the container 86 is filled with a heated gas, and the temperature of the infrared transparent substrate 10 is raised to a predetermined temperature set as a reference temperature. The temperature of the infrared transparent substrate 10 is the heater heating power source 7
Controlled by 6 and maintained at a constant temperature.

Next, the infrared rays emitted from the infrared light source 20 are made incident on the infrared transmission substrate 10 via the band-pass filter 50 and the incident optical system 48. The infrared rays incident on the infrared transparent substrate 10 undergo multiple internal reflection on the front and back surfaces of the substrate, and then are emitted to the outside of the substrate.

Next, the infrared rays emitted from the infrared transmitting substrate 10 are detected by the infrared detector 32 via the detection optical system 46. The amount of infrared light detected is in database 3
Accumulate in 8.

Thus, the measurement in the reference state is completed.

Next, the substrate to be measured is measured.

First, the infrared transparent substrate 10 which is the substrate to be measured.
Are installed in the container 86.

Then, similarly to the case of the measurement in the reference state, the temperature is raised to the same reference temperature as that set in the case of the measurement in the standard state and kept at a constant temperature. In addition,
When measuring the chemical substance in the atmosphere, the gas to be measured may be used as the gas taken in from the air duct 72. By doing so, not only the amount of the chemical substance attached to the infrared transparent substrate 10 can be measured but also the concentration of the chemical substance in the atmosphere can be measured.

Next, the infrared rays emitted from the infrared light source 20 are made incident on the infrared transmission substrate 10 through the band-pass filter 50 and the incident optical system 48. The infrared rays that have entered the infrared transmission substrate 10 are multiply internally reflected by the front and back surfaces of the infrared transmission substrate 10 and at the same time the infrared transmission substrate 10 is irradiated.
The information of the chemical substances adsorbed on the surface of the substrate is accumulated and probing, and then released to the outside of the infrared transmission substrate 10.

Next, the infrared rays emitted from the infrared transmitting substrate 10 are detected by the infrared detector 32 via the detection optical system 46. The amount of infrared light detected is in database 3
Accumulate in 8.

Thus, the measurement of the substrate to be measured is completed.

Then, the absorbance is calculated with reference to the light amount in the reference state and the light amount obtained from the substrate to be measured, which are accumulated in the database 38.

Next, with reference to a predetermined calibration curve stored in the database 38, the attached amount of the chemical substance attached on the infrared transmitting substrate 10 is calculated. If applicable, the concentration of the chemical substance in the atmosphere is calculated by referring to the predetermined calibration curve stored in the database 38.

As described above, according to this embodiment, it is possible to suppress the change in the amount of transmitted light due to the temperature change of the infrared transmitting substrate, so that the change in the amount of transmitted light due to the chemical substance attached on the infrared transmitting substrate is suppressed. It can be measured more accurately.
Therefore, the detection sensitivity of chemical substances can be improved.

[0151]

As described above, according to the present invention, infrared rays emitted after multiple reflections inside the infrared transparent substrate are detected, and the infrared rays are attached to the infrared transparent substrate based on the intensity of the detected infrared rays. In the chemical substance detection method that calculates the amount of attached chemical substance, the change in the amount of transmitted light due to the temperature change of the infrared transparent substrate is suppressed, so that the change in the amount of transmitted light due to the chemical substance attached to the infrared transparent substrate is more suppressed. Can be measured accurately. Thereby, the detection sensitivity of the chemical substance can be improved.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing an example of a chemical substance detection system in a chemical substance detection device according to the present invention.

FIG. 2 is a graph showing an example of an infrared transmission spectrum of a bandpass filter.

FIG. 3 is a schematic diagram showing an example of a substrate temperature control system in the chemical substance detection device according to the present invention.

FIG. 4 is a graph showing the relationship between the absorbance and the residual carbon deposited on the substrate.

FIG. 5 is a graph showing the relationship between the amount of attached chemical substance on the substrate and the concentration of the chemical substance in the atmosphere.

FIG. 6 is a schematic view and a plan view showing the structure of the chemical substance detection device according to the first embodiment of the present invention.

FIG. 7 is a schematic view and a plan view showing the structure of a chemical substance detection device according to a second embodiment of the present invention.

FIG. 8 is a schematic view and a plan view showing the structure of a chemical substance detection device according to a third embodiment of the present invention.

[Explanation of symbols]

10 ... Infrared transparent substrate 20 ... Infrared light source 30 ... Chemical substance detection means 32 ... Infrared detector 34 ... A / D converter 36 ... Arithmetic device 38 ... Database 40 ... Chopper 42 ... Lock-in amplifier 44 ... Chopper drive circuit 46 ... Detection optical system 48 ... Incident optical system 50 ... Band pass filter 60 ... Substrate temperature measuring means 70 ... Substrate temperature control means 72 ... Air duct 74 ... Heater 76 ... Heater heating power supply 78 ... Constant temperature bath 80 ... Constant temperature bath temperature controller 82, 84 ... Infrared light transmitting window 86 ... Container 88, 90 ... Windows

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Claims (12)

[Claims] 1. An infrared ray is incident on an infrared transmissive substrate, the infrared ray emitted from the infrared transmissive substrate after multiple reflection inside the infrared transmissive substrate is detected, and the infrared ray is detected based on the intensity of the detected infrared ray. In a chemical substance detection method for calculating the amount of attachment of a chemical substance attached to an infrared transparent substrate, in a reference state of the infrared transparent substrate, a first amount of light transmitted through the infrared transparent substrate is measured, In a state where the amount of the chemical substance on the infrared transmissive substrate is changed, the first light transmitted through the infrared transmissive substrate at a temperature substantially equal to the temperature of the infrared transmissive substrate when the first light amount is measured. 2. The chemical substance detection, wherein the amount of light of No. 2 is measured, and the amount of attachment of the chemical substance attached to the infrared transparent substrate is calculated in consideration of the first amount of light and the second amount of light. Method. 2. The chemical substance detection method according to claim 1, wherein when the first light amount and the second light amount are measured,
By measuring the temperature of the infrared transparent substrate and comparing the signal based on the measured temperature of the infrared transparent substrate and the signal based on a predetermined reference temperature, the temperature of the infrared transparent substrate is almost equal to the reference temperature. A method for detecting a chemical substance, which is characterized by maintaining the same temperature. 3. An infrared ray is incident on the infrared transparent substrate, the infrared ray emitted from the infrared transparent substrate after multiple reflection inside the infrared transparent substrate is detected, and the infrared ray is detected based on the intensity of the detected infrared ray. In a chemical substance detection method for calculating the amount of attachment of a chemical substance attached to an infrared transparent substrate, the temperature dependence of infrared transmittance of the infrared transparent substrate is measured, and the reference state of the infrared transparent substrate is measured. In, the first light amount transmitted through the infrared transmission substrate and the temperature of the infrared transmission substrate are measured, and the infrared transmission substrate is changed in a state where the amount of the chemical substance on the infrared transmission substrate is changed. The second amount of transmitted light and the temperature of the infrared transmitting substrate are measured, and the first light amount, the second amount of light, and the temperature dependency of the transmittance are taken into consideration to attach the infrared light onto the infrared transmitting substrate. Calculate the amount of adhered chemical substances Chemical sensor wherein the door. 4. The chemical substance detection method according to claim 1, wherein in the measurement of the first light amount and the second light amount, a wavelength range in which infrared absorption is caused by the chemical substance. A method for detecting chemical substances, characterized by selectively detecting infrared rays of the. 5. An infrared transparent substrate, an infrared light source for making infrared rays incident on the infrared transparent substrate, and detecting infrared rays emitted from the infrared transparent substrate after multiple reflection inside the infrared transparent substrate. A chemical substance analysis unit that calculates the amount of attached chemical substance on the infrared transmission substrate based on detected infrared radiation; a substrate temperature measurement unit that measures the temperature of the infrared transmission substrate; and the infrared transmission substrate Substrate temperature control means for changing the temperature of the, the substrate temperature control means based on the temperature of the infrared transmission substrate measured by the substrate temperature measuring means, to control the temperature of the infrared transmission substrate substantially constant And a substrate temperature stabilizing means for maintaining the chemical substance detection device. 6. The chemical substance detection device according to claim 5, wherein the substrate temperature control unit is a unit that blows a gas having a predetermined temperature onto the infrared transparent substrate. 7. The chemical substance detection device according to claim 5, wherein the substrate temperature control means is a constant temperature bath containing the infrared transparent substrate. 8. The chemical substance detection device according to claim 5, wherein the substrate temperature control unit includes a container that encloses the infrared transparent substrate, and a gas introduction unit that introduces a gas at a predetermined temperature into the container. A chemical substance detection device having. 9. The chemical substance detection device according to claim 5, wherein the substrate temperature stabilizing means is based on a measured temperature of the infrared transparent substrate measured by the substrate temperature measuring means. By comparing the signal with a signal based on a predetermined reference temperature,
A chemical substance detection device characterized in that the temperature of the infrared transparent substrate is maintained at a temperature substantially equal to the reference temperature. 10. The chemical substance detecting device according to claim 5, wherein the chemical substance detecting means transmits the infrared transmitting substrate in a reference state of the infrared transmitting substrate. The amount of light of No. 1 is measured, and the amount of the chemical substance on the infrared transmissive substrate is changed, the second amount of light transmitted through the infrared transmissive substrate is measured, and the first amount of light and the second amount of light are measured. Considering the light intensity of
A means for calculating the amount of the chemical substance attached to the infrared transparent substrate, wherein the substrate temperature stabilizing means is the temperature of the infrared transparent substrate at the time of measuring the first light amount, and A chemical substance detection device, characterized in that the temperature of the infrared transmitting substrate is controlled so that the temperature of the infrared transmitting substrate when measuring the second light amount becomes substantially equal. 11. An infrared transmissive substrate, an infrared light source for injecting infrared rays into the infrared transmissive substrate, a substrate temperature measuring means for measuring a temperature of the infrared transmissive substrate, and an interior of the infrared transmissive substrate. Infrared detection means for detecting infrared rays emitted from the infrared transmission substrate after reflection, based on the infrared rays detected by the infrared detection means and the temperature of the infrared transmission substrate measured by the substrate temperature measurement means, A chemical substance detection device, comprising: a chemical substance analysis means for calculating the amount of attached chemical substance on the infrared transparent substrate. 12. The chemical substance detection device according to claim 5, wherein the chemical substance detection means selectively detects infrared rays in a wavelength range corresponding to a specific molecular vibration, A chemical substance detection device, characterized in that the attached amount of the chemical substance is calculated based on the absorbance of infrared rays in the wavelength range.