Optical analyzer and composite analyzer

Abstract

To allow measurement of a wider wavelength range and reduce loss of energy of light sources, in an optical analyzer that irradiates optical cells storing samples with light, and detects light transmitted through the optical cells to analyze the samples.SOLUTION: An optical analyzer irradiates optical cells storing samples with light, and detects light transmitted through the optical cells to analyze the samples. The optical analyzer comprises: a first light source unit and a second light source unit that emit rays of light different in a spectrum from each other; an optical element that reflects part of the emitted light and transmits another part of the light, and has a first surface irradiated with the light from the first light source unit and a second surface irradiated with the light from the second light source unit; a first optical output port that is provided on an optical path of the light from the first light source unit reflected by the first surface and the light from the second light source unit transmitted through the second surface; and a second optical output port that is provided on an optical path of the light from the first light source unit transmitted through the first surface.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an optical analyzer that measures the component concentration of a chemical solution in, for example, a semiconductor manufacturing process, and a composite analyzer including the same. [Background technology]

[0002] As an example of a conventional analytical device, as shown in Patent Document 1, there is an optical analytical device that is connected to a pipe installed in a semiconductor manufacturing device and measures the concentration of a chemical solution (liquid sample) such as hydrofluoric acid (HF). This optical analytical device has an optical cell, a light irradiating unit that irradiates light onto the optical cell, and a light detecting unit that detects light transmitted through the optical cell, and is configured to calculate the concentration of a predetermined component contained in the liquid sample contained in the optical cell by a calculation unit that receives a light intensity signal from the light detector. The concentration thus obtained is used to control the concentration of the chemical solution flowing through the pipe. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2021-139668 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned optical analysis device, it is desirable to irradiate the optical cell with light in a wide wavelength range by a single device. For this reason, for example, a light source unit for irradiating light may be provided with both a deuterium lamp that emits light in the ultraviolet region and a halogen lamp that emits light in the visible to infrared wavelength range, and light from these light sources may be synthesized and emitted using an optical element such as a beam splitter that reflects part of the irradiated light and transmits part of it. In this way, the optical element reflects light emitted from, for example, the halogen lamp and transmits light emitted from the deuterium lamp, and synthesizes these lights, making it possible to extract light in the ultraviolet to infrared region. Also, by turning on only one of the lamps, it is possible to selectively extract light in the visible to infrared region or light in the ultraviolet region.

[0005] However, even if light of different wavelength ranges is selectively extracted from the light source unit, there is a problem that it is difficult to measure the entire wavelength range from the ultraviolet light region to the infrared light region using a single photodetector, since each photodetector has its own suitable sensitivity wavelength range. Another problem is that when configured in this way, the light from the halogen lamp that is not reflected by the optical element and transmitted through it is discarded, which not only makes it difficult to effectively utilize the energy of the light source, but also raises the concern that this unused light will become a radiant heat source and cause thermal effects.

[0006] The present invention has been made to solve the above-mentioned problems, and its main objective is to enable measurement over a wide wavelength range in an optical analysis device that analyzes a sample by irradiating light onto an optical cell containing the sample and detecting the transmitted light, and further to reduce and effectively utilize the energy loss of the light source. [Means for solving the problem]

[0007] That is, the optical analysis device of the present invention analyzes a sample by irradiating light onto an optical cell containing the sample and detecting the light transmitted through the optical cell, and is characterized by comprising a first light source unit and a second light source unit that emit light of different spectra from each other, an optical element that reflects part of the irradiated light and transmits part of it, having a first surface onto which light from the first light source unit is irradiated and a second surface onto which light from the second light source unit is irradiated, a first light output port provided on the optical path of the light from the first light source unit reflected by the first surface and the light from the second light source unit that has transmitted through the second surface, and a second light output port provided on the optical path of the light from the first light source unit that has transmitted through the first surface.

[0008] With this configuration, the light from the first light source unit reflected by the first surface of the optical element and the light from the second light source unit transmitted through the second surface of the optical element are combined and guided to the first light output port, so that the reflected light from the first light source unit, the transmitted light from the second light source unit, or the combined light of these can be selectively output from the first light output port and irradiated onto the optical cell. Furthermore, the light from the first light source unit transmitted through the first surface of the optical element is guided to the second light output port, so that the transmitted light from the first light source unit can be effectively utilized without being discarded and irradiated onto the optical cell. Then, if the light output from the first light output port and the light output from the second light output port are detected by photodetectors having sensitivity wavelength ranges suitable for each, it becomes possible to perform measurements over a wide wavelength range, for example, from the ultraviolet light region to the infrared light region. In this way, according to the configuration of the present invention, the reflected light from the first light source unit and the transmitted light from the second light source unit are combined using an optical element, and the light from the first light source that has passed through the optical element is further utilized, so that the reflected light from the first light source unit, the transmitted light from the second light source unit, the combined light, and the transmitted light from the first light source can be selectively output, reducing energy loss from the light source and enabling measurements over a wide wavelength range.

[0009] In the optical analysis device, it is preferable that the intensity of light emitted from one of the first light source section and the second light source section is greater than the intensity of light emitted from the other. In this way, by making the light intensity of the first light source unit and the second light source unit different, it is possible to output light having different wavelength characteristics from each light output port in a well-balanced manner, taking into account the difference between the reflectance and transmittance of the optical element. For example, when the light transmittance of the optical element is higher than the light reflectance, the first light source unit may be made to have a higher light intensity than the second light source unit.

[0010] In a specific embodiment of the present invention, one of the first light source unit and the second light source unit has a halogen lamp as a light source, and the other has a deuterium lamp as a light source.

[0011] In a specific embodiment of the present invention, one of the first light source unit and the second light source unit emits light in the wavelength range from visible light to infrared light, and the other emits light in the wavelength range of ultraviolet light. In this embodiment, it is possible to measure a wide wavelength range from the ultraviolet region to the infrared region.

[0012] In addition, it is preferable that the optical element has a reflectance greater than a transmittance or a transmittance greater than a reflectance in the wavelength region of the light emitted by the first light source unit and the second light source unit.

[0013] In the optical analysis device, the optical element is preferably constructed using an uncoated quartz plate. For example, when a half mirror made of flat glass coated with a dielectric multilayer film is used as an optical element, the material constituting the dielectric multilayer film is prone to absorbing ultraviolet light, and this may lead to early deterioration. By using an uncoated quartz plate (i.e., a quartz plate that has not been subjected to a coating treatment) as an optical element, it is possible to suppress the absorption of ultraviolet light and inhibit deterioration. In addition, since an uncoated quartz plate has the optical characteristic of having a higher transmittance than reflectance, this optical element can combine the transmitted light of a deuterium lamp, which has a relatively small light amount, and the reflected light of a halogen lamp, which has a relatively large light amount, in a well-balanced manner with an appropriate light amount ratio.

[0014] The optical analyzer is preferably provided such that the first light output port and the second light output port face in substantially the same direction. In this way, since the first optical output port and the second optical output port face in the same direction, it is easy to connect an optical fiber or the like for extracting light.

[0015] Furthermore, it is preferable that the optical analysis device further comprises a first optical cell and a second optical cell to which light output from the first light output port and the second light output port, respectively, is irradiated, and a first photodetector and a second photodetector which detect light transmitted through the first optical cell and the second optical cell, respectively, and have different sensitivity wavelength ranges. With this configuration, the light output from the first optical output port and the light output from the second optical output port can be detected by photodetectors with appropriate sensitivity wavelength ranges, making it possible to perform measurements over a wide wavelength range. The phrase "having different wavelength sensitivity ranges" means that the wavelength sensitivity ranges are not the same, in other words, that at least a part of the wavelength sensitivity ranges do not overlap each other. Furthermore, when one of the first light source unit and the second light source unit emits light in the visible to infrared wavelength range and the other emits light in the ultraviolet wavelength range, it is preferable that one of the first photodetector and the second photodetector has a sensitivity wavelength range from the ultraviolet to visible light range and the other has a sensitivity wavelength range in the infrared range.

[0016] The present invention also provides a composite analytical device comprising the optical analytical device described above, and a conductivity meter that measures the conductivity of the sample, or a pH meter that measures the pH of the sample. Such a composite analysis device can provide the same effects as the optical analysis device described above. Effect of the Invention

[0017] According to the present invention described above, in an optical analysis device that analyzes a sample by irradiating light onto an optical cell containing a test liquid sample and detecting the transmitted light, it is possible to measure a wide wavelength range and further reduce energy loss from the light source. [Brief description of the drawings]

[0018] [Figure 1] 1 is a diagram showing the overall configuration of an optical analysis device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram illustrating an internal configuration of a light source unit according to the embodiment. [Diagram 3] 4 is a graph showing an example of the light output spectrum of a deuterium lamp and a halogen lamp in the ultraviolet and visible light ranges. [Figure 4] 4 is a graph showing an example of the light output spectrum of a halogen lamp in the infrared light range. [Diagram 5] FIG. 11 is a diagram illustrating an internal configuration of a light source unit according to another embodiment. [Figure 6] FIG. 1 is a diagram showing the overall configuration of a composite analysis device including a light source analysis device of the present embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] An optical analysis device 100 according to one embodiment of the present invention will now be described with reference to the drawings.

[0020] The optical analysis device 100 of this embodiment is used, for example, in a semiconductor manufacturing line, and measures the concentration of a chemical solution (liquid sample) used, for example, in a cleaning process in semiconductor manufacturing, and more specifically, is a spectrophotometer that measures the concentration by irradiating the liquid sample with light and measuring the absorbance of the liquid sample. Examples of chemical solutions include SC-1 (ammonia hydrogen peroxide solution), SC-2 (hydrochloric acid hydrogen peroxide solution), SPM (sulfuric acid hydrogen peroxide solution), FPM (hydrofluoric acid hydrogen peroxide solution), and BHF (buffered hydrofluoric acid solution).

[0021] Specifically, as shown in FIG. 1, the optical analysis device 100 includes a light source unit 1, an optical cell 2 connected to the light source unit 1 via a light guide mechanism having an optical fiber 4 or the like, a photodetector 3 connected to the optical cell 2 via a light guide mechanism having an optical fiber 4 or the like, and a calculation unit 5. In the optical analysis device 100, a liquid sample such as a chemical solution is contained in the optical cell 2, and light emitted from the light source unit 1 is irradiated onto the optical cell 2, the light transmitted through the optical cell 2 is detected by the photodetector 3, and the calculation unit 5, which receives a light intensity signal from the photodetector 3, calculates the concentration of a predetermined component contained in the liquid sample. The concentration thus obtained is used to control the concentration of the chemical solution, etc. The optical cell 2 is, for example, a flow cell provided in a circulation path formed by a chemical solution pipe connected to a chemical solution tank of a semiconductor cleaning device. The optical cell 2 may be an in-line flow cell directly incorporated into the pipe inside the semiconductor cleaning device. The material of the optical cell 2 is preferably sapphire when chemical solution resistance against hydrofluoric acid or the like is required, and is preferably quartz, which has better light transmission, when chemical solution resistance is not required. Also, the cell length may be changed so that the wavelength range and absorbance to be measured can be selected for each liquid medicine.

[0022] Thus, the optical analysis device 100 of this embodiment has two optical cells (first optical cell 21, second optical cell 22) and two photodetectors (first photodetector 31, second photodetector 32) with different sensitivity wavelength ranges for one light source unit 1. Specifically, the light source unit 1 has two light output ports (first light output port 1P1, second light output port 1P2) that emit light with different spectra, and the light emitted from each light output port is irradiated onto the first optical cell 21 and the second optical cell 22 via a light guide mechanism. The light transmitted through the first optical cell 21 and the second optical cell 22 is detected by the first photodetector 31 and the second photodetector 32 via the light guide mechanism, respectively.

[0023] As shown in Fig. 2, the light source unit 1 includes a casing 1C, a first light source section 11 and a second light source section 12 that are housed in the casing 1C and emit light beams with different spectra, and a plurality of optical elements (a first optical element 13 and a second optical element 14) that transmit and / or reflect the light beams emitted from the first light source section 11 and the second light source section 12. "Emitting light beams with different spectra" means that light beams with different spectra in at least a part of the wavelength range are emitted, and also includes light beams with different spectra in the entire wavelength range. The light beams emitted from the first light source section 11 and the second light source section 12 are transmitted and reflected by the plurality of optical elements and guided to a first light output port 1P1 and a second light output port 1P2 that are provided on one side wall of the casing 1C and face in approximately the same direction.

[0024] The first light source unit 11 emits light in the visible light region to the infrared light region, having an optical output spectrum as shown in Figures 3 and 4. Specifically, the first light source unit 11 has a halogen lamp 11a as a light source, and a lens 11b that adjusts the spread of the light emitted from the halogen lamp 11a.

[0025] The second light source unit 12 emits light in the ultraviolet region having an optical output spectrum, for example, as shown in Fig. 3. Specifically, the second light source unit 12 has a deuterium lamp 12a as a light source and a lens 12b for adjusting the spread of the light emitted from the deuterium lamp 12a.

[0026] In this embodiment, the first light source unit 11 and the second light source unit 12 are arranged so that their optical paths intersect (for example, preferably perpendicular to each other, but not limited to this) in the casing 1C. Here, the lenses 11b and 12b are arranged so that their optical axes intersect. A first optical element 13 is arranged near an intersection CP where these two optical paths intersect. This first optical element 13 combines light from the first light source unit 11 and light from the second light source unit 12 and emits the combined light. More specifically, this first optical element 13 transmits a part of the irradiated light and reflects a part of it, and is specifically configured using an uncoated quartz plate.

[0027] The first optical element 13 of this embodiment uses an uncoated quartz plate, and has optical properties in which the light transmittance (eg, about 85% to about 95%) is higher than the light reflectance (eg, about 5% to about 15%).

[0028] Here, the first optical element 13 has a first surface 13a onto which light from the first light source unit 11 is irradiated, and a second surface 13b onto which light from the second light source unit 12 is irradiated. The first surface 13a and the second surface 13b face in opposite directions and are parallel to each other. The angle and position of the first optical element 13 are set so that the light paths of the light from the first light source unit 11 reflected by the first surface 13a (reflected light) and the light from the second light source unit 12 transmitted through the second surface 13b (transmitted light) are approximately the same. That is, in the first optical element 13, the reflected light of the light from the first light source unit 11 and the transmitted light of the light from the second light source unit 12 are combined. Here, the halogen lamp has a characteristic that the light amount is greater than that of the deuterium lamp, and as described above, the first optical element 13 has an optical characteristic that the light reflectance is smaller than the light transmittance, so that the light from the first light source unit 11 reflected by the first surface 13a of the first optical element 13 and the light from the second light source unit 12 transmitted through the second surface 13b of the first optical element 13 are combined with an appropriate balance of light amounts. Then, a first light output port 1P1 is provided on the optical path of this combined light (combined light), and from the first light output port 1P1, a combined light (light in the ultraviolet to infrared light range) having the optical output spectrum shown in Fig. 3 and combined with the reflected light from the first light source unit and the transmitted light from the second light source unit is output.

[0029] On the other hand, a second optical element 14 is disposed on the optical path of the light from the first light source unit 11 that has passed through the first surface 13a of the first optical element 13. The second optical element 14 is a reflecting mirror 14 such as a plane mirror having a reflecting surface that reflects the irradiated light. A second optical output port 1P2 is provided on the optical path of the light from the first light source unit 11 that has been reflected by the reflecting mirror 14, and the transmitted light (light in the visible light region to the infrared light region) from the first light source unit 11 having the optical output spectrum shown in FIG. 4 is emitted from the second optical output port 1P2. Note that the light from the second light source unit 12 that is reflected by the second surface 13b of the first optical element 13 also reaches the second optical output port 1P2, but as described above, the light amount of the deuterium lamp is smaller than the light amount of the halogen lamp, and the first optical element 13 has an optical characteristic in which the light reflectance is smaller than the light transmittance, so most of the light that reaches the second optical output port 1P2 is transmitted light from the first light source unit 11.

[0030] The first light output port 1P1 and the second light output port 1P2 are connected to ends of optical fibers 4 for guiding the output light to the first optical cell 21 and the second optical cell 22, respectively. As a result, the first optical cell 21 is irradiated with a composite light (light in the ultraviolet to infrared light range) of the reflected light from the first light source unit 11 and the transmitted light from the second light source unit 12 via the optical fiber 4, and the second optical cell 22 is mainly irradiated with the transmitted light (light in the visible to infrared light range) from the first light source unit 11 via the optical fiber 4.

[0031] The photodetector 3 includes a spectroscope that separates and detects the light transmitted through the optical cell 2. The photodetector obtains the optical absorption spectrum (spectroscopic spectrum) of the transmitted light. The optical absorption spectrum in this embodiment is a concept that includes an absorbance spectrum obtained from the optical absorption spectrum of the transmitted light and the optical absorption spectrum of the incident light. In this embodiment, the first photodetector 31 and the second photodetector 32 are linear image sensors that are configured using different detection elements according to the wavelength of light to be measured. Specifically, the first photodetector 31 is configured using a silicon detection element having a sensitivity wavelength range in the ultraviolet light region and the visible light region, and the second photodetector 32 is configured using an InGaAs detection element having a sensitivity wavelength range in the infrared light region.

[0032] According to the optical analysis device 100 of the present embodiment configured as described above, the light (light in the visible light region to the infrared light region) from the first light source unit 11 reflected by the first surface 13a of the first optical element 13 and the light (light in the ultraviolet light region) from the second light source unit 12 transmitted through the second surface 13b of the first optical element 13 are combined and guided to the first light output port 1P1, so that light in the ultraviolet light region to the infrared light region can be output from the first light output port 1P1 and irradiated to the first optical cell 21. Furthermore, the light from the first light source unit 11 transmitted through the first surface 13a of the first optical element 13 is guided to the second light output port 1P2, so that the transmitted light (visible light region to infrared light region) from the first light source unit 11 can be effectively utilized without being wasted and can be irradiated to the second optical cell 22. Here, an uncoated quartz plate having optical properties of sufficiently high light transmittance relative to light reflectance is used as the first optical element 13, so that a combined light (light in the ultraviolet to infrared region) obtained by combining light from the first light source unit 11, which has a relatively large amount of light, and light from the second light source unit, which has a relatively small amount of light, with an appropriate light amount balance can be output from the first light output port 1P1, while the second light output port 12 can mainly output light (light in the visible to infrared region) from the first light source unit 11. This allows light with different spectra to be output with an appropriate amount of light from the first light output port 1P1 and the second light output 1P2. The light output from the first light output port 1P1 is detected by the first photodetector 31 having a wavelength sensitivity range from the ultraviolet light region to the visible light region, and the light output from the second light output port 1P2 is detected by the second photodetector 32 having a wavelength sensitivity range from the infrared light region, so that the wavelength range from the ultraviolet light region to the visible light region can be measured. Examples of the measurement of the spectrum of the output light from each output port 1P1, 1P2 by the first photodetector 31 and the second photodetector 32, respectively, are shown in Figures 3 and 4.

[0033] The present invention is not limited to the above-described embodiment. For example, the first optical element 13 may have optical properties of reflecting light in the visible light region and transmitting light in the ultraviolet light region and the infrared light region, or conversely, may have optical properties of transmitting light in the visible light region and reflecting light in the ultraviolet light region and the infrared light region. The first optical element 13 may have a reflectance higher than a transmittance. In this case, the arrangement of the first light source unit 11 and the second light source unit 12, or the arrangement of the first photodetector 31 and the second photodetector 32 may be interchanged.

[0034] The first optical element 13 in the above embodiment is a quartz plate, but is not limited to this. In other embodiments, the first optical element 13 may be a glass plate made of any material, such as CaF2 (calcium fluoride), BK7, sapphire, etc. In addition, the first optical element 13 in other embodiments may be a polka dot beam splitter, a reflective ND filter, a dielectric multilayer beam splitter, etc.

[0035] In the above embodiment, the first light source unit 11 includes a halogen lamp 11a as a light source, but is not limited thereto. In other embodiments, the first light source unit 11 may include one or more LEDs as a light source that emit light in the infrared region and light in the visible region. Similarly, the second light source unit 12 may include one or more LEDs as a light source that emits light in the ultraviolet region.

[0036] In other embodiments of the light source unit 1, the first light source section 11 and the second light source section 12 emit light of different spectra, and the light from the first light source section 11 and the light from the second light source section 12 are combined by the first optical element 13 to output a combined light from the first light output port 1P1, and the light from the first light source section 11 that has passed through the first optical element 13 is output from the second light output port 1P2. As long as this is a configuration, the wavelength range of the light emitted from each light source section 11, 12 and the wavelength range of the light output from the first light output port 1P1 and the second light output port 1P2 may be arbitrary.

[0037] In the above embodiment, the second optical element 14 is disposed on the optical path of the light from the first light source that has passed through the first optical element 13, but this is not limiting. The light source unit 1 in other embodiments may not include the second optical element 14, and may be configured so that the light from the first light source that has passed through the first optical element 13 is guided directly to the second optical output port 1P2.

[0038] Furthermore, in the above embodiment, the first light source unit 11 and the second light source unit 12 are arranged so that the optical axes of the respective lenses 11b and 12b themselves intersect in the casing 1C, but this is not limited thereto. In other embodiments, for example, as shown in FIG. 5, the light emitted from the first light source unit 11 may be reflected by the third optical element 15, which is a reflecting mirror, and guided to the first optical element 13, and the light emitted from the first light source unit 11 and the light emitted from the second light source unit 12 may intersect in this first optical element 13. That is, in this specification, "arranged so that the optical paths of the first light source unit 11 and the second light source unit 12 intersect with each other" means that the light arriving from the first light source unit 11 and the light arriving from the second light source unit 12 intersect in the first optical element 13 that combines these lights.

[0039] In the above embodiment, the first light source unit 11 and the second light source unit 12 are arranged so that their optical paths intersect with each other, and the first optical element 13 is arranged near the intersection CP, but this is not limited to this. In the optical analysis device 100 of other embodiments, the first optical element 13 is present on the optical path of the light from the first light source unit 11 and the light from the second light source unit 12, the first optical output port 1P1 is provided on the optical path of the light from the first light source unit 11 reflected by the first optical element 13 and the light from the second light source unit 12 transmitted through the first optical element 13 (more specifically, on the optical path of the combined light), and the second optical output port 1P2 is provided on the optical path of the light from the first light source unit 11 transmitted through the first optical element 13, the positions and orientations of the first light source unit 11, the second light source unit 12, and the first optical element 13 may be changed as appropriate.

[0040] In the above embodiment, the light of the first light source unit 11 and the light of the second light source unit 12 are combined in the first optical element 13, but this is not limiting. In other embodiments, the light of the first light source unit 11 and the light of the second light source unit 12 may be combined after passing through the first optical element 13.

[0041] The optical analysis device 100 of another embodiment is not limited to one that analyzes liquid samples such as chemical solutions, but may also analyze gas samples such as gases. A similar device configuration may also be used to measure fluorescence generated from a sample in an optical cell. In this way, a single device can sweep the wavelength of excitation light over a wide wavelength range.

[0042] Furthermore, the optical analysis device 100 described above may be applied to a combined analysis device 400 that measures the concentration of a predetermined component contained in a liquid sample using the optical absorption spectrum of the liquid sample and a characteristic value of the liquid sample measured electrochemically. Hereinafter, one embodiment of such a combined analysis device 400 will be described with reference to FIG.

[0043] <Device configuration> The combined analytical device 400 measures the concentration of a measurement target component contained in a liquid sample, such as a chemical liquid used in, for example, a semiconductor manufacturing device. This combined analytical device 400 is provided, for example, in a chemical liquid pipe that supplies the chemical liquid, and measures the concentration of the measurement target component in the chemical liquid. The concentration thus obtained is used to control the concentration of the chemical liquid, etc. The chemical liquid is a mixed chemical liquid (mixed sample) of two or more components, and may include, for example, a component that becomes conductive when dissolved, a component that does not become conductive, or a component that is a hydrogen ion (H + ) contains components that are correlated with

[0044] 6, the composite analyzer 400 includes an optical measurement unit (specifically, the optical analyzer) 100 that measures the optical absorption spectrum of a liquid sample, an electrochemical measurement unit 200 that electrochemically measures a characteristic value of the liquid sample, and an information processing device 300 that processes measurement information obtained from the optical measurement unit 100 and the electrochemical measurement unit 200. The characteristic value is a physical property value that is correlated with the concentration of a component to be measured that is contained in the liquid sample.

[0045] As described above, the optical measurement unit 100 is an absorbance meter that irradiates a liquid sample with light to measure the absorbance of the liquid sample. The optical cell 2 housed therein is provided in a first sample flow path L1 formed by a chemical liquid piping (not shown) connected to a chemical liquid tank T of a semiconductor manufacturing device, for example. The first sample flow path L1 may be connected to either the first optical cell 21 or the second optical cell 22 depending on the type of the component to be measured.

[0046] The electrochemical measurement section 200 of this embodiment includes a conductivity meter 210 that measures the conductivity (electrical conductivity) of a liquid sample, and a pH meter 220 that measures the pH of the liquid sample.

[0047] Specifically, the conductivity meter 210 applies an AC voltage between two electrodes 211, 212 and measures the conductivity (electrical conductivity) of the liquid sample based on the flowing current. The conductivity meter 210 of this embodiment is provided on the upstream or downstream side of the optical measurement unit 100 in the first sample flow path L1 in which the optical measurement unit 100 is provided. Note that the conductivity meter 210 may be of an AC 4-pole type or an electromagnetic induction type, in addition to an AC 2-pole type. The conductivity meter 210 may also be provided in a sample flow path other than the first sample flow path L1.

[0048] The pH meter 220 measures the pH of the liquid sample based on the potential difference generated between the pH glass electrode (working electrode) 221 and the reference electrode 222. The pH meter 220 of this embodiment is provided in a second sample flow path L2 formed by a chemical liquid pipe (not shown) connected to the chemical liquid tank 5, separate from the first sample flow path L1. The pH meter 220 may be provided in the first sample flow path L1, for example, on the upstream side or downstream side of the optical measurement unit 100.

[0049] The information processing device 300 calculates the concentration of a measurement target component in a liquid sample using the optical absorption spectrum (or absorbance spectrum) obtained by the optical measurement unit 100, the conductivity obtained by the conductivity meter 210, and the pH obtained by the pH meter 220. The information processing device 300 is a computer having a CPU, a memory, an input / output interface, an AD converter, output means such as a display, and input means such as a keyboard. The CPU and peripheral devices work together to fulfill the function of the concentration calculation unit 310 based on a component concentration calculation program stored in the memory.

[0050] Specifically, the concentration calculation unit 310 calculates the concentration of the measurement target component by multivariate analysis using the optical absorption spectrum and characteristic values ​​(conductivity and pH) as explanatory variables. Note that possible multivariate analyses include multiple regression analysis (MLR or ILS), principal component regression analysis (PCR), least squares method (CLS), partial least squares method (PLS (PLS1 or PLS2)), etc.

[0051] Here, the concentration calculation unit 310 performs a first or second derivative process on the optical absorption spectrum and performs multivariate analysis using the derivative values ​​as explanatory variables. The concentration calculation unit 310 also performs multivariate analysis using the values ​​of each of a plurality of wavelengths in the optical absorption spectrum as explanatory variables.

[0052] Specifically, the concentration calculation section 310 calculates the concentration of the measurement target component by multivariate analysis using the following formula.

[0053]

number

[0054] where Abs i (Absorbance) is the differential processing of the optical absorption spectrum, and is the value for each of multiple wavelengths (λ1, λ2, . . . λn). In addition, the coefficient a i, b, and c are the concentration regression coefficients for wavelength λi, conductivity, and pH, respectively. The concentration regression coefficients correspond to the weights of each explanatory variable. Furthermore, k is a calibration curve obtained in advance, and S is the measurement data (actual measurement data) of the liquid sample from the optical measurement unit 100 and the electrochemical measurement unit 200. Here, the calibration curve is obtained by multivariate analysis of the measurement data from the optical measurement unit 100 and the electrochemical measurement unit 200 obtained when a standard sample with a known concentration is measured, using the above formula. When using two explanatory variables, absorbance and conductivity, simply enter zero into the pH term in the above equation 1. When using two explanatory variables, absorbance and pH, simply enter zero into the conductivity term in the above equation 1.

[0055] In addition, various modifications and combinations of the embodiments may be made as long as they do not go against the spirit of the present invention. [Explanation of symbols]

[0056] 100...Optical analyzer 1 Light source unit 11...1st light source section 12...Second light source section 13 First Optical Element 1P1: First optical output port 1P2...Second optical output port 2. Optical Cell 3. Photodetector CP...Intersection

Claims

1. A method for analyzing a sample by irradiating an optical cell containing the sample with light and detecting light transmitted through the optical cell, a first light source unit and a second light source unit that emit light of different spectra; an optical element that reflects a portion of irradiated light and transmits a portion of the light, the optical element having a first surface onto which light from the first light source unit is irradiated and a second surface onto which light from the second light source unit is irradiated; a first light output port provided on an optical path of light from the first light source unit reflected by the first surface and light from the second light source unit transmitted through the second surface; a second light output port provided on an optical path of light from the first light source unit that has passed through the first surface.

2. The optical analyzer according to claim 1 , wherein the intensity of light emitted from one of the first light source unit and the second light source unit is greater than the intensity of light emitted from the other.

3. 3. The optical analyzer according to claim 1, wherein one of the first light source unit and the second light source unit includes a halogen lamp as a light source, and the other includes a deuterium lamp as a light source.

4. 4. The optical analysis device according to claim 3, wherein one of the first light source unit and the second light source unit emits light in the wavelength range from visible light to infrared light, and the other emits light in the wavelength range of ultraviolet light.

5. The optical analysis device according to claim 1 or 2, wherein the optical element has a reflectance greater than a transmittance or a transmittance greater than a reflectance in the wavelength range of light emitted by the first light source unit and the second light source unit.

6. 3. The optical analysis device according to claim 1, wherein the optical element is constructed using an uncoated quartz plate.

7. 3. The optical analysis device according to claim 1, wherein the first light output port and the second light output port are provided so as to face in substantially the same direction.

8. a first optical cell and a second optical cell that are irradiated with light output from the first light output port and the second light output port, respectively; 3. The optical analysis device according to claim 1, further comprising a first photodetector and a second photodetector, each of which detects light transmitted through the first optical cell and the second optical cell, and which have different sensitivity wavelength ranges.

9. A method for measuring the concentration of a target component in a sample, The optical analysis device according to claim 1 ; a conductivity meter for measuring the conductivity of the sample or a pH meter for measuring the pH of the sample; and a concentration calculation unit that calculates the concentration of the component to be measured by multivariate analysis using the optical absorption spectrum of the sample measured by the optical analysis device and the conductivity or pH of the sample measured by the conductivity meter or the pH meter as explanatory variables.

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