DCR gas absorption spectrophotometric analysis device, DCR gas absorption spectrophotometric analysis method, and DCR gas absorption spectrophotometric analysis program

Abstract

To provide an absorption spectrophotometry device for DCR gas capable of separating only absorbency of a DCR gas and calculating concentration thereof even for a mixed gas consisting of the DCR gas and a CO gas absorption spectra of which overlap with each other.SOLUTION: An absorption spectrophotometry device for DCR gas comprises: a filter 31 for DCR which transmits light in a first wave number range including an absorption peak of a DCR gas; a filter 32 for CO which transmits light in an absorption wave number range of a CO gas and in a second wave number range different from the first wave number range; and a DCR gas amount calculator 4 which calculates the amount of the DCR gas based upon first absorbency A1 measured with the light transmitted through the filter 31 for DCR and second absorbency AC2 measured with the light transmitted through the filter 32 for CO.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a DCR gas absorption spectrophotometric analyzer for measuring the amount of DCR gas in a mixed gas consisting of CO gas as a carrier gas and DCR gas as a component gas. [Background technology]

[0002] In order to form ruthenium thin films or ruthenium compound thin films by chemical vapor deposition methods such as CVD and ALD, DCR (Dodecacarbonyl Triruthenium: (Ru3(CO) 12 The DCR gas is supplied to the vacuum chamber at a predetermined concentration and flow rate using, for example, CO gas as a carrier gas.

[0003] The concentration of DCR gas in a mixed gas of DCR gas and CO gas can be measured by using the NDIR (Non Dispersive Infrared) method.

[0004] However, since almost the entire DCR absorption spectrum overlaps with a part of the CO absorption spectrum, when analysis is performed at the DCR absorption wavelength, the influence of both DCR and CO absorption occurs. For this reason, it is not possible to separate the absorbance of the DCR alone, and it is not possible to calculate the accurate concentration and flow rate of the DCR gas.

[0005] For example, when using NDIR to measure components of exhaust gas, an optical filter that transmits almost the entire infrared ray in the absorption wavelength range of each gas in Patent Document 1 is used to measure the CO concentration or CO2 concentration of the measurement target gas in the exhaust gas, and also to measure the moisture concentration, which is an interference component whose absorption wavelength range overlaps with that of the measurement target gas. Then, the moisture concentration is subtracted from the concentration of the measurement target gas measured as a zero point interference correction.

[0006] However, it is difficult to accurately measure the DCR concentration by simply applying the above-mentioned method to a mixed gas of DCR and CO. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP2003-172700 Public Relations Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made in consideration of the above-mentioned problems, and aims to provide a DCR absorption spectrophotometer that can separate only the absorbance of the DCR gas and calculate its concentration, even in a mixed gas consisting of DCR gas and CO gas whose absorption spectra overlap. [Means for solving the problem]

[0009] That is, the present invention is a method for producing a fluorine-containing gas comprising: a carrier gas, CO gas, and a component gas, DCR (Ru3(CO) 12 ) gas, the amount of DCR gas in a mixed gas consisting of the gas, is measured based on a DCR filter that transmits light in a first wavenumber range including an absorption peak of the DCR gas, a CO filter that transmits light in a second wavenumber range that is the absorption wavenumber range of the CO gas and is different from the first wavenumber range, and a first absorbance measured by the light transmitted through the DCR filter and a second absorbance measured by the light transmitted through the CO filter, the amount of the DCR gas is calculated based on and a DCR gas amount calculator for estimating an interference influence estimation unit which estimates an interference influence absorbance, which is the absorbance of the CO gas in the first wavenumber range, based on the second absorbance, an absorbance correction unit which subtracts the interference influence absorbance from the first absorbance to correct it to the absorbance of the DCR gas, and a conversion unit which converts the absorbance of the DCR gas corrected by the absorbance correction unit into the amount of the DCR gas contained in the mixed gas.

[0010] In addition, the present invention uses a carrier gas, CO gas, and a component gas, DCR (Ru3(CO)12 a CO filter to transmit light in a second wavenumber range which is the absorption wavenumber range of the CO gas and different from the first wavenumber range; and calculating the amount of the DCR gas based on a first absorbance measured by the light transmitted through the DCR filter and a second absorbance measured by the light transmitted through the CO filter. In calculating the amount of the DCR gas, the method includes estimating an interference-affected absorbance, which is the absorbance of the CO gas in the first wavenumber range, based on the second absorbance, correcting the absorbance of the DCR gas by subtracting the interference-affected absorbance from the first absorbance, and converting the amount of the DCR gas contained in the mixed gas based on the absorbance of the DCR gas corrected by the absorbance correction unit.

[0011] With such a configuration, it is possible to obtain the first absorbance, which is affected by the absorption of the DCR gas and the CO gas due to the action of the DCR filter, and the second absorbance, which is almost not affected by the absorption of the DCR gas due to the action of the CO filter and which accurately reflects the concentration of CO gas.

[0012] That is, the absorbance influenced by interference, which is the absorbance of the CO gas in the first wavenumber range, can be accurately estimated based on the second absorbance. Furthermore, the first absorbance is corrected to the absorbance of the DCR gas by subtracting the absorbance influenced by interference from the first absorbance, so that an accurate absorbance of the DCR gas can be obtained.

[0013] In order to ensure that the first absorbance is most influenced by the absorption peak of DCR gas and that the second absorbance is most influenced by the absorption peak of CO gas, thereby obtaining a more accurate amount of DCR gas, the first wavenumber range should include 2067 / cm and the second wavenumber range should include 2165 / cm.

[0014] In order to eliminate the need for complex calculations and, for example, to be able to accurately calculate the concentration of the DCR gas sequentially at a control period required for concentration control, the absorbance correction unit only needs to multiply the second absorbance by a predetermined coefficient to calculate the interference-affected absorbance.

[0015] In order to obtain substantially the same effects as the DCR absorption spectrometer of the present invention by updating the program of an existing absorption spectrometer, the carrier gas CO gas and the component gas DCR (Ru3(CO) 12 and a DCR gas absorption spectrophotometric analysis program for use in a DCR gas absorption spectrophotometric analyzer including a DCR filter that transmits light in a first wavenumber range including an absorption peak of the DCR gas, and a CO filter that transmits light in a second wavenumber range that is the absorption wavenumber range of the CO gas and is different from the first wavenumber range. The DCR gas absorption spectrophotometric analysis program determines the amount of the DCR gas in a mixed gas consisting of a DCR gas and a CO gas, based on a first absorbance measured by the light transmitted through the DCR filter and a second absorbance measured by the light transmitted through the CO filter. The DCR gas amount calculator may include an interference effect estimation unit that estimates an interference-affected absorbance, which is the absorbance of the CO gas in the first wavenumber range, based on the second absorbance, an absorbance correction unit that subtracts the interference-affected absorbance from the first absorbance to correct it to the absorbance of the DCR gas, and a conversion unit that converts the absorbance of the DCR gas corrected by the absorbance correction unit into the amount of the DCR gas contained in the mixed gas.

[0016] The DCR gas absorption analysis program may be distributed electronically, or may be recorded on a program recording medium such as a CD, DVD, or flash memory. Effect of the Invention

[0017] In this way, the DCR gas absorption spectrophotometric analyzer according to the present invention can accurately estimate the interference-affected absorbance due to the absorption of CO gas contained in the first absorbance from the second absorbance reflecting the concentration of CO gas, and correct the first absorbance based on the interference-affected absorbance to obtain the absorbance due to the absorption of only the DCR gas. Therefore, it becomes possible to accurately calculate quantities such as the concentration and partial pressure of the DCR gas. [Brief description of the drawings]

[0018] [Figure 1] FIG. 1 is a schematic diagram showing a DCR gas absorption spectrophotometer according to an embodiment of the present invention. [Diagram 2] 4 is a graph showing the absorption spectra of DCR gas and CO gas, and the transmission settings of each filter in the embodiment. [Diagram 3] FIG. 2 is a functional block diagram showing the configuration of a DCR gas amount calculator in the embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] A DCR gas absorption spectrophotometric analyzer 100 according to one embodiment of the present invention will be described with reference to the accompanying drawings.

[0020] This DCR gas absorption spectrophotometer 100 measures the concentration of DCR gas supplied into a chamber by the NDIR method in a semiconductor manufacturing process using a chemical vapor deposition method such as a CVD method or an ALD method. A mixture of CO gas as a carrier gas and DCR gas as a component gas is supplied into the chamber. This is to prevent the CO group of DCR from separating before being supplied to the chamber, which would cause decomposition of DCR.

[0021] As shown in Figure 1, the DCR gas absorption analysis device 100 comprises a translucent, approximately cylindrical cell 2 that is attached to a flow path through which a mixed gas flows, a light source 1 that introduces infrared light having a predetermined spectrum into the cell 2 from one end face side of the cell 2, a light detection mechanism 3 that detects infrared light emitted from the other end face side of the cell 2, and a DCR gas amount calculator 4 that calculates the concentration of the DCR gas based on the output of the light detection mechanism 3.

[0022] Each part will be described in detail.

[0023] The light source 1 is configured to emit infrared light in a wave number range that includes at least the wave numbers of the absorption peak of DCR gas and the absorption peak of CO gas.

[0024] The cell 2 is a so-called flow cell that has a mixed gas inlet opening in its side portion on the light source 1 side and a mixed gas outlet opening in its side portion on the detection mechanism side, and is configured so that the mixed gas flows within the cell 2.

[0025] The light detection mechanism 3 includes three sets of filters and detectors provided to face the other end surface side of the cell 2. In this embodiment, the three sets of filters and detectors are a DCR filter 31 and a DCR detector 31D for measuring a first absorbance A1 due to absorption of the DCR gas and the CO gas, and a DCR filter 31 and a DCR detector 31D for measuring a second absorbance A1 due to absorption of only the CO gas. C2 The CO filter 32 and CO detector 32D are used to measure CO, and the reference filter 33 and reference detector 33D output a comparison signal. Each filter is a bandpass filter, and each filter transmits a different wavenumber range of light. For each detector, the same type is used, even if it is a pyroelectric infrared sensor.

[0026] Each filter will now be described in detail.

[0027] The DCR filter 31 is configured to transmit light in a first wavenumber range including the absorption peak of the DCR gas. Since the absorption spectrum peak of the DCR gas is at 2067 / cm, the first wavenumber range is configured to include the absorption peak and wavenumbers in the vicinity thereof.

[0028] On the other hand, the CO filter 32 is configured to transmit light in a second wavenumber range that is an absorption wavenumber range of CO gas and different from the first wavenumber range. In this embodiment, the second wavenumber range is configured so that the absorption spectrum of the DCR gas is substantially absent in the second wavenumber range, or the absorption of the DCR gas is almost negligible compared to the absorption of the CO gas. More specifically, the second wavenumber range is set to include 2165 / cm, which is the absorption peak of CO gas and where the absorption of the DCR gas is almost negligible, and wavenumbers in the vicinity thereof.

[0029] The reference filter 33 is configured to transmit infrared light in a wavenumber range in which there is almost no absorption by the DCR gas and the CO gas. In other words, the comparison signal reflects the intensity of infrared light in the case where there is substantially no absorption.

[0030] Figure 2 shows the measurement results of the absorption spectrum when the mixed gas is flowed and when only CO gas is flowed. The flow rate of CO gas is set to the same value in both measurement results. As can be seen from the measurement results in Figure 2, there is almost no change in absorbance when the mixed gas is flowed and when only CO gas is flowed in the vicinity of 2165 / cm. In other words, by measuring the absorbance in the second wavelength range using a CO filter, it is possible to obtain absorbance that reflects the influence of only CO gas in the mixed gas from the output of the CO detector even when the mixed gas is flowed. On the other hand, since absorption occurs only in CO gas in the vicinity of 2067 / cm, it can be seen that when the mixed gas is flowed, the absorbance measured in the first wavelength range is influenced by not only the absorbance of DCR gas but also the absorbance of CO gas.

[0031] Next, the configuration of the DCR gas amount calculator 4 will be described with reference to the functional block diagram of FIG.

[0032] The DCR gas amount calculator 4 calculates a first absorbance A1, which is a measurement result in the first wave number range obtained from the light detection mechanism 3, and a second absorbance A2, which is a measurement result in the second wave number range. C2 The concentration of the DCR gas in the mixed gas is calculated based on the above. The function of this DCR gas amount calculator 4 is realized by executing a DCR gas absorption analysis program stored in the memory in a so-called computer equipped with, for example, a CPU, a memory, an A / D converter, a D / A converter, and various input / output means. Specifically, the DCR gas amount calculator 4 realizes at least the functions of a first absorbance calculator 41, a second absorbance calculator 42, an interference effect estimator 43, a related data storage unit 44, an absorbance corrector 44, and a converter 45 through the cooperation of each device.

[0033] The first absorbance calculation unit 41 receives the DCR+CO signal (first output signal) output from the DCR detector 31D and the comparison signal output from the reference detector 33D, and calculates the absorbance A of the DCR gas in the first wavenumber range based on the values ​​indicated by these signals. D1 and the absorbance of CO gas A C1 The first absorbance A1 is calculated as the sum of A1 = A D1 +A C1 It should be noted that the absorbance can be calculated using a known method.

[0034] The second absorbance calculation unit 42 receives the CO signal (second output signal) output from the CO detector 32D and the comparison signal output from the reference detector 33D, and calculates the absorbance A of the CO gas in the second wavenumber range based on the values ​​indicated by these signals. C2 The second absorbance A is C2 Calculate.

[0035] The interference effect estimation unit 43 estimates an interference effect absorbance A, which is the absorbance of CO gas in the first wavenumber range, based on the second absorbance. C1 The interference effect estimation unit 43 estimates, for example, the second absorbance A C2 Multiply by an appropriate coefficient K to get A C1 Calculate A C1 AC2 are the input variables, A C1 Alternatively, it may be determined by a relational expression with

[0036] The absorbance correction unit 44 corrects the first absorbance A1 to the interference-affected absorbance A C1 The absorbance of the DCR gas, A, is obtained by subtracting D1 That is, A D1 =A1-A C1 =A1-K×A C2 It can be expressed as:

[0037] The conversion unit 45 converts the absorbance A of the DCR gas corrected by the absorbance correction unit 44. D1 Based on the Beer-Lambert law, the measured value is converted into the concentration of the DCR gas contained in the mixed gas. This converted DCR gas concentration is output and displayed externally, or used for concentration control.

[0038] According to the DCR gas absorption spectrophotometric analyzer 100 of the present embodiment configured as described above, even when a mixed gas is flowing, the second absorbance A where absorption of CO gas alone occurs is detected by using the CO filter 32. C2 From this value, the interference absorbance A1, which is the effect of absorption of CO gas contained in the first absorbance A1, can be calculated. C1 can be estimated.

[0039] In addition, the first absorbance A1 is subtracted from the interference absorbance A C1 By subtracting the absorbance A due to the absorption of DCR gas only, D1 Therefore, the concentration of the DCR gas in the mixed gas can be accurately calculated in the conversion unit 45.

[0040] Other embodiments will now be described.

[0041] The DCR filter and the CO filter are not limited to those shown in the above embodiment, and the wave number range to be transmitted may be set appropriately.

[0042] The light detection mechanism is not limited to that shown in the above embodiment, and may utilize the configuration of an existing NDIR analyzer, etc. For example, instead of preparing multiple detectors, only one detector may be prepared, and a filter placed between the cell and the detector may be switched at high speed.

[0043] The conversion unit may output the partial pressure or flow rate of the DCR gas instead of the concentration. The partial pressure can be converted from the concentration definition formula.

[0044] In addition, various modifications of the embodiments and combinations of parts of each embodiment may be made without going against the spirit of the present invention. [Explanation of symbols]

[0045] 100···DCR gas absorption analyzer 1...Light source 2 Cell 3. Optical detection mechanism 31 DCR filter 31D···DCR detector 32 CO Filter 32D...CO detector 33 Reference Filter 33D...Reference detector 4. DCR gas amount calculator 41...First absorbance calculation section 42...Second absorbance calculation section 43 Interference effect estimation unit 44...Absorbance correction section 45...conversion section

Claims

1. A spectrophotometric analyzer for DCR gas for measuring the amount of DCR gas in a mixed gas consisting of CO gas as a carrier gas and DCR (Ru(CO)) gas as a component gas, comprising: a DCR filter that transmits light in a first wavenumber range including an absorption peak of the DCR gas; a CO filter that transmits light in a second wavenumber range that is an absorption wavenumber range of the CO gas and is different from the first wavenumber range; a DCR gas amount calculator that calculates an amount of the DCR gas based on a first absorbance measured by the light transmitted through the DCR filter and a second absorbance measured by the light transmitted through the CO filter, The DCR gas amount calculator an interference effect estimation unit that estimates an interference effect absorbance, which is the absorbance of the CO gas in the first wavenumber range, based on the second absorbance; an absorbance correction unit that subtracts the interference-affected absorbance from the first absorbance to correct the absorbance to the absorbance of the DCR gas; a conversion unit that converts the absorbance of the DCR gas corrected by the absorbance correction unit into an amount of the DCR gas contained in the mixed gas, 11. The DCR gas absorption spectrophotometric analyzer, wherein the first wavenumber range includes 2067 / cm and the second wavenumber range includes 2165 / cm.

2. 2. The DCR gas absorption spectrophotometric analyzer according to claim 1, wherein the absorbance correction unit calculates the interference-affected absorbance by multiplying the second absorbance by a predetermined coefficient.

3. A method for spectrophotometric analysis of DCR gas for measuring an amount of DCR gas in a mixed gas consisting of CO gas as a carrier gas and DCR (Ru(CO)) gas as a component gas, comprising: providing a DCR filter to transmit light in a first wavenumber range including an absorption peak of the DCR gas; providing a CO filter so as to transmit light in a second wavenumber range that is an absorption wavenumber range of the CO gas and is different from the first wavenumber range; and calculating an amount of the DCR gas based on a first absorbance measured by the light transmitted through the DCR filter and a second absorbance measured by the light transmitted through the CO filter; In calculating the amount of DCR gas, estimating an interference-affected absorbance, which is an absorbance of the CO gas in the first wavenumber range, based on the second absorbance; subtracting the interference-affected absorbance from the first absorbance to correct the absorbance of the DCR gas; and converting the corrected absorbance of the DCR gas into an amount of the DCR gas contained in the mixed gas, 11. The method of claim 10, wherein the first wavenumber range includes 2067 / cm and the second wavenumber range includes 2165 / cm.

4. A DCR gas absorption spectrophotometric analysis program for measuring an amount of DCR gas in a mixed gas consisting of CO gas as a carrier gas and DCR (Ru3(CO)12) gas as a component gas, the program being used in a DCR gas absorption spectrophotometric analysis device having a DCR filter that transmits light in a first wavenumber range including an absorption peak of the DCR gas, and a CO filter that transmits light in a second wavenumber range that is the absorption wavenumber range of the CO gas and is different from the first wavenumber range, The DCR gas absorption analysis program a computer is caused to function as a DCR gas amount calculator that calculates the amount of the DCR gas based on a first absorbance measured by the light transmitted through the DCR filter and a second absorbance measured by the light transmitted through the CO filter, The DCR gas amount calculator an interference effect estimation unit that estimates an interference effect absorbance, which is the absorbance of the CO gas in the first wavenumber range, based on the second absorbance; an absorbance correction unit that subtracts the interference-affected absorbance from the first absorbance to correct the absorbance to the absorbance of the DCR gas; a conversion unit that converts the absorbance of the DCR gas corrected by the absorbance correction unit into an amount of the DCR gas contained in the mixed gas, The first wavenumber range includes 2067 / cm, and the second wavenumber range includes 2165 / cm.

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