Gas analyzers

Abstract

A gas analyzing device 100 for analyzing a component to be measured that is included in a gas by irradiating the gas with laser light and detecting the laser light that is transmitted through the gas, the gas analyzing device 100 being configured such that a moment in the gravity direction that occurs about a fulcrum of an attachment point, etc., is reduced to suppress optical axis deviation as much as possible, wherein the gas analyzing device 100 comprises: a gas cell 1 attached to a piping H through which a gas flows, the gas being introduced to the gas cell 1; and a long optical cell 2 connected from a prescribed connection direction X to the gas cell 1, the optical cell 2 housing an optical system 6 that is supported by a surface plate 10 in a state of being disposed on the optical path of the laser light, and the optical cell 2 is configured so as to be upright with respect to the connection direction X.

Description

[Technical Field]

[0001] The present invention relates to a gas analyzer. [Background technology]

[0002] As shown in Patent Document 1, a conventional gas analyzer is known that uses an infrared absorption method in which a gas introduced into a gas cell is irradiated with laser light and the laser light that has passed through the gas is detected to analyze the components to be measured contained in the gas.

[0003] Such gas analyzers have been used, for example, to analyze exhaust gases emitted from vehicles. In such applications, the analyzer is installed in a predetermined location, and the device is configured, for example, by mounting a light source, detector, optical system, etc. on a single surface plate, and housing these in a stationary optical cell.

[0004] Recently, there has been a demand for applying the above-mentioned gas analyzer to the analysis of material gases and by-product gases used in, for example, semiconductor manufacturing processes. In such applications, a gas cell is sometimes attached to piping connected to a process chamber in order to grasp the state inside the process chamber as quickly as possible. In such cases, the piping layout varies depending on the site, and therefore the attitude of the gas analyzer after attachment also varies.

[0005] If this happens, and the gas cell is attached to a pipe extending vertically and the optical cell or surface plate is connected to this gas cell in a lying position, the weight of the optical cell will generate a moment in the direction of gravity with the gas cell attachment point as the fulcrum, causing the surface plate to bend and resulting in a problem of misalignment of the optical axis of the laser light, as shown in Figure 10. This type of misalignment of the optical axis due to a moment is not limited to cases where the gas cell is attached to a pipe, but is also a problem that occurs when, for example, the optical cell or surface plate is attached to a predetermined location.

[0006] The above-mentioned problem is particularly pronounced when a multi-reflection cell is used as the gas cell, because the angle of incidence of the laser light entering the gas cell of the multi-reflection cell must be adjusted to within ±0.1 degrees, and even a slight deviation in the optical axis caused by bending of the surface plate reduces the signal strength, making it impossible to ensure analytical accuracy. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Japanese Patent Application Laid-Open No. 2017-187468 Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been made to solve the above problems, and its main objective is to reduce the moment in the direction of gravity that occurs with the mounting point or the like as a fulcrum, thereby minimizing optical axis misalignment as much as possible. [Means for solving the problem]

[0009] That is, the gas analyzer according to the present invention is a gas analyzer that analyzes a component to be measured contained in a gas by irradiating the gas with laser light and detecting the laser light that has passed through the gas, and is characterized in that it comprises a gas cell that is attached to a pipe through which the gas flows and into which the gas is introduced, and a long optical cell that is connected to the gas cell from a predetermined connection direction and that houses an optical system supported on a long base plate while being positioned on the optical path of the laser light, and the optical cell and the base plate are upright in the connection direction.

[0010] In such a gas analyzer, the optical cell and base are upright. Therefore, when the gas cell is attached to a pipe extending vertically, for example, the distance from the attachment point of the gas cell to the center of gravity of the optical cell is shorter than in a conventional configuration in which the optical cell and base are laid down. This reduces the moment in the direction of gravity that occurs with this attachment point as a fulcrum, and minimizes optical axis misalignment. Furthermore, by erecting the optical cell, the optical system is arranged so that the light path is three-dimensional, which allows for efficient use of the space within the optical cell and also makes it possible to reduce the size and weight.

[0011] The surface plate is preferably disposed opposite the gas cell. With this configuration, the surface plate can be moved closer to the gas cell side, and the moment in the direction of gravity can be further reduced compared to the conventional configuration in which the surface plate is tilted down.

[0012] Furthermore, the gas analyzer according to the present invention is a gas analyzer that analyzes a component to be measured contained in a gas by irradiating the gas with a laser beam and detecting the laser beam that has passed through the gas, and is characterized in that it comprises: a gas cell attached to a pipe through which the gas flows and into which the gas is introduced; and an elongated optical cell that is connected to the gas cell from a predetermined connection direction and that houses an optical system supported on a base while being positioned on the optical path of the laser beam, and the base is positioned opposite the gas cell.

[0013] In such a gas analyzer, the base is disposed opposite the gas cell; in other words, the base stands upright in the direction of connection between the gas cell and the optical cell. Therefore, when the gas cell is attached to a pipe extending vertically, for example, the distance from the attachment point of the gas cell to the center of gravity of the optical cell is shorter than in a conventional configuration in which the base is laid down. This reduces the moment in the direction of gravity generated with this attachment point as a fulcrum, and minimizes optical axis misalignment.

[0014] An embodiment in which the above-described effects are more significantly exhibited can be one in which a light source that emits the laser light, a detector that detects the laser light, the optical system on the light-emitting side that guides the laser light emitted from the light source to the gas cell, and the optical system on the light-receiving side that guides the laser light that has passed through the gas to the detector are supported on the base plate. With this configuration, many components such as the light source, detector, and various optical systems are supported on the base plate, so the moment reduction effect obtained by placing the base plate on the gas cell side can be more significantly exerted.

[0015] Many gas analyzers used in semiconductor manufacturing are equipped with a heating mechanism for heating a gas cell and a heat insulating material covering the gas cell. In such a configuration, when attempting to position the optical cell relative to the gas cell, it is conceivable to attach the optical cell to peripheral components of the gas cell, since the gas cell itself is covered with a heat insulating material. However, because the peripheral structure of the gas cell is complex, the above-mentioned attachment method may result in accumulated misalignment of the peripheral components, causing misalignment of the optical axis. Therefore, in a configuration comprising a heating mechanism for heating the gas cell and a heat insulating material covering the gas cell, it is preferable to further comprise a beam member having one end connected to the optical cell and the other end located inside the heat insulating material and connected to the gas cell, connecting the optical cell and the gas cell. With this configuration, the optical cell and the gas cell are connected via a beam member, so that the gas cell can be temperature-controlled while minimizing the impact on the optical axis caused by misalignment of the peripheral components of the gas cell. Furthermore, by interposing a beam member between the gas cell and the optical cell, the optical cell can be positioned at a distance from the gas cell, thereby reducing the thermal influence from the gas cell on the optical cell. Furthermore, if the optical cell is attached to the beam member in a pre-positioned state, the optical cell can be positioned relative to the gas cell by positioning and attaching the beam member relative to the gas cell. This eliminates the need for adjustment of the optical system even when the beam member and the optical cell are removed from the gas cell, improving maintainability.

[0016] In order to prevent the beam members from reducing the heat insulating performance, it is preferable that the beam members have a higher heat insulating property than at least the surface plate.

[0017] It is preferable that the optical system on the light projection side that guides the laser light to the gas cell includes at least two reflecting mirrors that reflect the laser light. This allows the optical axis of the laser light to be adjusted in the appropriate direction with high precision, making it possible to set the angle of incidence of the laser light with respect to the gas cell with high precision, and by supporting multiple reflecting mirrors on the base plate, the moment reduction effect obtained by positioning the base plate on the gas cell side can be significantly demonstrated.

[0018] In a configuration including an adjustment mechanism for adjusting the position or attitude of the optical system, it is preferable that an operating portion for operating the adjustment mechanism faces the opposite side to the center of the optical cell. With this configuration, it is possible to adjust the optical axis of the laser light after assembling the device, and since the operating part faces the outside of the optical cell, it is easy to operate during adjustment.

[0019] If the gas cell has a pair of reflecting mirrors provided therein to multiple-reflect the laser light, the moment reduction effect of the present invention can be more significantly exhibited.

[0020] In a more specific embodiment, the gas cell is provided in a pipe connected to a chamber in which a semiconductor manufacturing process is carried out.

[0021] In order to reduce the weight of the optical cell, it is preferable that a second optical cell be provided in addition to the optical cell, which is connected to the gas cell from a predetermined connection direction and contains an optical system supported on a base plate while being positioned on the optical path of the laser light, and the base plate of the second optical cell is positioned opposite the gas cell. With this configuration, various optical systems can be housed in both the optical cell and the second optical cell, so that the weight of each optical cell can be reduced. Furthermore, since the base plate of the second optical cell is also positioned opposite the gas cell, the distance from the mounting point of the gas cell to the center of gravity of the second optical cell is shortened, and the moment in the direction of gravity generated with this mounting point as the fulcrum can be reduced. [Effects of the Invention]

[0022] According to the present invention as described above, it is possible to reduce the moment in the direction of gravity that occurs with the attachment point or the like as a fulcrum, and to minimize the misalignment of the optical axis. [Brief explanation of the drawings]

[0023] [Figure 1] 1 is a schematic diagram showing a semiconductor manufacturing apparatus incorporating a gas analyzer according to an embodiment of the present invention; [Figure 2] FIG. 2 is a schematic diagram showing the internal configuration of the gas analyzer of the embodiment. [Figure 3] FIG. 2 is a schematic diagram showing the internal configuration of an optical cell in the gas analyzer of the embodiment. [Figure 4] FIG. 2 is a schematic diagram showing the overall configuration of the gas analyzer according to the embodiment. [Figure 5] FIG. 10 is a schematic diagram showing the internal configuration of a gas analyzer according to another embodiment. [Figure 6] FIG. 10 is a schematic diagram showing the internal configuration of a gas analyzer according to another embodiment. [Figure 7] FIG. 10 is a schematic diagram showing the arrangement of a second optical cell in a gas analyzer according to another embodiment. [Figure 8]FIG. 10 is a schematic diagram showing the configuration of a gas analyzer according to another embodiment. [Figure 9] FIG. 10 is a schematic diagram showing the configuration of a gas analyzer according to another embodiment. [Figure 10] FIG. 1 is a schematic diagram showing the configuration of a conventional gas analyzer. [Explanation of symbols]

[0024] 100 Gas analyzer 200 Chamber H...Piping 1 Gas cell 2. Optical Cell 3...Heating mechanism 4. Insulation 5. Laser light source 6...Optical system 7. Photodetector 8. Signal Processing Section 9 Casing 10. Surface plate 11 Beam member F1: Flange F2: Flange X Connection direction Y...tube axis direction M Longitudinal direction N Short side direction DETAILED DESCRIPTION OF THE INVENTION

[0025] A gas analyzer according to an embodiment of the present invention will be described below with reference to the drawings.

[0026] <Device configuration> The gas analyzer 100 of this embodiment is incorporated into a semiconductor manufacturing apparatus, as shown in FIG. 1, and measures the concentration or partial pressure of a halide, which is a component to be measured, contained in, for example, a source gas used in a semiconductor manufacturing process or a by-product gas generated by the semiconductor manufacturing process (hereinafter, these will be simply referred to as "gas"). Possible halides here include fluoride, chloride, bromide, etc. However, this gas analyzer 100 may be adapted to measure components other than halides, and does not necessarily need to be incorporated into a semiconductor manufacturing apparatus.

[0027] This gas analyzer 100 irradiates a gas with laser light and detects the laser light that has passed through the gas, thereby analyzing the components to be measured contained in the gas by infrared absorption. Specifically, as shown in FIG. 1, the gas analyzer 100 includes a gas cell 1 into which a gas is introduced, and an optical cell 2 that houses various optical systems and is arranged on the optical path of the laser light.

[0028] The gas cell 1 of this embodiment guides gases introduced into or discharged from a chamber 200 where a semiconductor manufacturing process is performed. As shown in FIG. 1 , the gas cell 1 is attached to a pipe H connected to the exhaust port of the chamber 200. A pressure control valve CV, which controls the pressure in the chamber 200, and a vacuum pump CP, which evacuates the chamber 200, are provided in this order in the pipe H. The gas cell 1 is located closer to the chamber 200 than the vacuum pump CP. The inlet port of the gas cell 1 is connected upstream of the pressure control valve CV, and the outlet port of the gas cell 1 is connected downstream of the pressure control valve CV. This allows the gas cell 1 to be depressurized to a predetermined pressure lower than atmospheric pressure. However, the arrangement of the gas cell 1 is not limited to this. For example, the inlet port may be connected downstream of the pressure control valve CV.

[0029] Specifically, as shown in Fig. 2, the gas cell 1 has an entrance port La and an exit port Lb for laser light, and is provided with an inlet port Pa for introducing gas into the interior and an outlet port Pb for discharging the gas inside. The gas cell 1 also has a pair of reflecting mirrors MR provided inside, making it a multi-reflection cell that multiple-reflects laser light. Specifically, the gas cell 1 is configured such that laser light incident on one of the reflecting mirrors MR exits from the same reflecting mirror MR after multiple reflections. In other words, the entrance port La and exit port Lb for laser light are provided on the same side.

[0030] In addition, a heating mechanism 3, such as a heater using an electric heating wire, is provided around the gas cell 1 to heat the inside of the gas cell 1 to a predetermined temperature (e.g., 200°C), and a heat insulating material 4, such as a resin, is provided around the heating mechanism 3 to surround the gas cell 1.

[0031] 2 and 3, the optical cell 2 includes a light source 5 that irradiates the gas cell 1 with laser light, an optical system 6 provided on the optical path of the laser light, a photodetector 7 that detects the laser light that has passed through the gas, a signal processing unit 8 that calculates the concentration or partial pressure of the component to be measured using an optical absorption signal obtained from the output signal of the photodetector 7, and a casing 9 that houses these components. In Fig. 3, the casing 9 and other components are omitted and are depicted in a different orientation from that in Fig. 2 in order to explain the internal structure of the optical cell 2.

[0032] The light source 5 is a laser tube that emits wavelength-modulated laser light, and emits, for example, mid-infrared (2.5 to 25 μm) laser light. This light source 5 is capable of modulating the oscillation wavelength within a predetermined wavelength modulation range using a given current (or voltage). Note that other types of light sources may be used as long as the oscillation wavelength is variable, and the oscillation wavelength may be changed by, for example, changing the temperature. The light source 5 may also be a quantum cascade laser (QCL), a type of semiconductor laser, or may be one that emits laser light of a specific wavelength, rather than one that emits wavelength-modulated laser light. The light source 5 may also be one that emits light of various wavelengths, such as infrared light or ultraviolet light. Specifically, the light source 5 is not limited to a laser light source that emits laser light, but may be any type that emits light, such as a thermal light source, an LED light source, a deuterium lamp, or a xenon lamp. When the above-mentioned multi-reflection cell is used as the gas cell, the light source 5 is preferably one that emits laser light that is high in intensity and does not easily attenuate even when reflected multiple times.

[0033] The optical system 6 is divided into a light-projecting side optical system 6 (hereinafter also referred to as a light-projecting side optical system 61) that guides the laser light emitted from the light source 5 to the gas cell 1, and a light-receiving side optical system 6 (hereinafter also referred to as a light-receiving side optical system 62) that guides the laser light that has passed through the gas cell 1 to the photodetector 7. The light-projecting side optical system 61 is provided with at least two reflecting mirrors that reflect the laser light, and the light-receiving side optical system 62 is provided with at least two reflecting mirrors that reflect the laser light. Here, three reflecting mirrors are provided as the light-projecting side optical system 61 and two reflecting mirrors are provided as the light-receiving side optical system 62, and these are specifically plane mirrors, concave mirrors, or the like.

[0034] The optical cell 2 of this embodiment also includes an adjustment mechanism 63 for adjusting the position or posture of the reflecting mirror, which is the optical system 6. Here, the adjustment mechanisms 63 and the reflecting mirrors are provided in one-to-one correspondence, and an operation unit 631 for a user to operate this adjustment mechanism 63 is arranged so as to face the opposite side to the center of the optical cell 2, that is, so as to face outward with its back to the center.

[0035] Here, the photodetector 7 is a thermal type such as a relatively inexpensive thermopile, but other types, such as quantum photoelectric elements with good responsiveness such as HgCdTe, InGaAs, InAsSb, PbSe, etc., may also be used.

[0036] The signal processing unit 8 comprises analog electrical circuits consisting of buffers, amplifiers, etc., digital electrical circuits consisting of a CPU, memory, etc., and AD converters, DA converters, etc. that mediate between these analog and digital electrical circuits. The CPU and its peripheral devices work together in accordance with a predetermined program stored in a predetermined area of ​​the memory, and thereby perform the functions of a light source control unit that controls the output of the light source 5, and of a calculation unit that receives an output signal from the photodetector 7 and processes the value to calculate the concentration or partial pressure of the component to be measured.

[0037] The casing 9 houses the various components described above and is elongated. This is because one or more components, such as the circuit board that constitutes the signal processing unit 8, are elongated, which causes the optical cell 2 to also be elongated. The casing 9 of this embodiment is roughly rectangular parallelepiped-shaped, and one of its longitudinal walls is thicker than the other walls and functions as a base 10 that supports the various components.

[0038] The surface plate 10 supports at least the optical system 6 arranged on the optical path of the laser light, and is a long, flat plate extending along the longitudinal direction of the optical cell 2. The surface plate 10 of this embodiment supports the above-mentioned light-emitting side optical system 61 and light-receiving side optical system 62, and also supports the light source 5 and photodetector 7, and thus supports most of the total weight of the optical cell 2.

[0039] 2 and 4, the optical cell 2 configured as above is connected to the gas cell 1 in a predetermined connection direction X. More specifically, the connection direction X of the optical cell 2 and the gas cell 1 is a direction intersecting the flow direction Y of the gas introduced into the gas cell 1, i.e., the axial direction Y of the pipe H to which the gas cell 1 is connected, and here is set to a direction perpendicular to the gas flow direction Y and the axial direction Y of the pipe H. That is, the optical cell 2 of this embodiment is connected in the horizontal direction to the gas cell 1 attached to the pipe H extending in the vertical direction.

[0040] In this embodiment, the optical cell 2 stands upright in the connection direction X with the gas cell 1. Note that the state of standing upright in the connection direction X here is a concept that includes not only an upright state in which the optical cell 2 stands upright (perpendicular to) the connection direction X, but also a state in which the optical cell 2 is slightly tilted from the upright state.

[0041] More specifically, the optical cell 2 is connected to the gas cell 1 in a position where its longitudinal direction M intersects with the connection direction X, and here, the longitudinal direction M and the connection direction X are perpendicular to each other. In addition, in this embodiment, as shown in FIG. 3 , the laser tube serving as the light source 5 described above is arranged such that its tube axis is aligned along the short-side direction N, which is a direction perpendicular to the longitudinal direction M of the optical cell 2. In other words, the emission direction of the laser light immediately after being emitted from the light source 5 is the short-side direction N of the optical cell 2. As various types of light source 5 may be used as described above, the emission direction from the light source 5 is not limited to the short-side direction N of the optical cell 2.

[0042] In this configuration, the above-mentioned surface plate 10 is disposed opposite the gas cell 1. That is, the surface plate 10 is disposed closer to the gas cell 1 than the center of the entire optical cell 2, and in this embodiment, the surface plate 10 is directly or indirectly connected to the gas cell 1.

[0043] More specifically, in this embodiment, as shown in Figures 2 and 4, a beam member 11 that connects the gas cell 1 and the optical cell 2 is interposed between the gas cell 1 and the optical cell 2, more specifically, between the gas cell 1 and the base plate 10.

[0044] One end of this beam member 11 is connected to the optical cell 2, and the other end is located inside the thermal insulation material 4 and connected to the gas cell 1. More specifically, one end, i.e., a flange portion F2 on the optical cell 2 side, is fastened to the surface plate 10, for example, with screws, and the other end, i.e., a flange portion F1 on the gas cell 1 side, is fastened to the wall surface of the gas cell 1, for example, with screws. A light passage hole Lc through which the laser light passes is formed inside the beam member 11. The beam member 11 has higher thermal insulation properties than at least the surface plate 10, and here is made of the same or a different type of resin as the thermal insulation material 4 described above. The other end penetrates the thermal insulation material 4 so as to be located inside the thermal insulation material 4.

[0045] <Effects of this embodiment> According to the gas analyzer 100 of this embodiment configured as described above, the optical cell 2 is erected in the connection direction X, and the base 10, which accounts for most of the total weight of the optical cell 2, is located on the gas cell 1 side. Therefore, when the gas cell 1 is attached to a pipe H extending vertically, for example, the distance from the attachment point of the gas cell 1 to the center of gravity of the optical cell 2 is shorter than in the conventional configuration in which the optical cell 2 is lying down. This reduces the moment in the direction of gravity generated with this attachment point as a fulcrum, and minimizes optical axis misalignment. In particular, the gas cell 1 of this embodiment is a multi-reflection cell, and the angle of incidence of the laser light incident on the gas cell 1 needs to be adjusted to within ±0.1 degrees. Since a deviation of the optical axis of several microns caused by bending of the surface plate 10 causes a signal error, the moment reduction effect described above is more pronounced.

[0046] Moreover, by erecting the optical cell 2, the optical system 6 is arranged so that the optical path is three-dimensional, so that the space within the optical cell 2 can be used efficiently, and the size and weight can also be reduced.

[0047] Furthermore, since the light-projecting optical system 61 is provided with at least two reflecting mirrors, the optical axis of the laser light can be adjusted in an appropriate direction with high precision, making it possible to set the incident angle of the laser light with respect to the gas cell 1 with high precision.

[0048] Furthermore, since the laser tube serving as the light source 5 is arranged so that its tube axis is aligned with the short direction N of the optical cell 2, the longitudinal direction M of the optical cell 2 can be made more compact than when the tube axis is aligned with the longitudinal direction M of the optical cell 2.

[0049] Furthermore, since it is equipped with an adjustment mechanism 63 for adjusting the position or attitude of the optical system 6, it is possible to adjust the optical axis of the laser light after assembling the device, and since the operating part 631 faces the outside of the optical cell 2, it is easy to operate during adjustment.

[0050] In addition, since the gas cell 1 is equipped with a heating mechanism 3 for heating the gas cell 1 and a heat insulating material 4 surrounding the gas cell 1, it is possible to control the temperature of the gas cell 1, and it is possible to prevent, for example, deterioration of the gas to be measured.

[0051] Furthermore, as described above, in a configuration including the heating mechanism 3 and the heat insulating material 4, if the optical cell is attached to a peripheral component of the gas cell (e.g., the heat insulating material 4), the peripheral structure of the gas cell 1 is complex, and therefore, there is a risk that misalignment of the peripheral components will accumulate, resulting in a misalignment of the optical axis. However, in this embodiment, the gas cell 1 and the optical cell 2 are connected via the beam member 11, so that the gas cell 1 can be configured to be temperature-controllable, while minimizing the effect on the optical axis caused by misalignment of the peripheral components of the gas cell 1. Furthermore, by interposing a beam member 11 between the gas cell 1 and the optical cell 2, the optical cell 2 can be positioned at a distance from the gas cell 1, thereby reducing the thermal influence from the gas cell 1 to the optical cell 2. Furthermore, if the optical cell 2 is attached in advance in a positioned state to the beam member 11, then the optical cell 2 can be positioned relative to the gas cell 1 by positioning and attaching this beam member 11 relative to the gas cell 1. This eliminates the need to adjust the optical system 6 even if the beam member 11 and the optical cell 2 are removed from the gas cell 1, thereby improving maintainability.

[0052] In addition, since the beam member 11 has the same insulating properties as the insulating material 4, the thermal influence from the gas cell 1 to the optical cell 2 described above can be more reliably reduced, and a decrease in insulating properties due to the beam member 11 can also be prevented. Furthermore, the larger the cross-sectional area of ​​the beam member 11, the larger the second moment of area becomes, which makes it possible to reduce the deflection of the beam member 11 and, in turn, to further reduce the optical axis deviation.

[0053] <Other embodiments> For example, although the gas cell 1 and the optical cell 2 are connected by a single beam member 11 in the above embodiment, they may be connected by two or more beam members 11 as shown in FIG. In this way, by providing a plurality of beam members 11, the heat insulating material 4 can be made thicker, and the temperature control function can be further ensured.

[0054] 6, the gas analyzer 100 according to the present invention does not necessarily have to include a temperature control mechanism for the gas cell 1, and in this case, the heating mechanism 3 and the heat insulating material 4 in the above embodiment can be eliminated. In this case, the gas cell 1 and the optical cell 2 may be directly connected without the intermediary of a beam member 11 or the like.

[0055] Furthermore, in the above embodiment, a single optical cell 2 is connected to the gas cell 1, but as shown in Figure 7, one or more second optical cells 2' may be connected to the gas cell 1. In other words, the gas analyzer 100 according to the present invention may further include, in addition to the optical cell 2, a second optical cell 2' that is connected to the gas cell 1 from a predetermined connection direction and contains an optical system that is supported on a base plate while being positioned on the optical path of the laser light. With this configuration, various optical systems can be housed in both the optical cell and the second optical cell, so that the weight of each optical cell can be reduced.

[0056] Specifically, for example, one of the optical cell 2 and the second optical cell 2' may house the light source 5 and the light-emitting optical system, and the other may house the photodetector 7 and the light-receiving optical system. In this case, as shown in Figure 7(A), the optical cell 2 and the second optical cell 2' may be arranged opposite each other with the gas cell 1 in between, or as shown in Figure 7(B), they may be arranged so that the connection direction of the optical cell 2 and the gas cell 1 intersects with the connection direction of the second optical cell 2' and the gas cell 1.

[0057] In such a configuration, it is preferable that the base of the second optical cell 2' is arranged opposite to the gas cell 1. This arrangement shortens the distance from the mounting point of the gas cell 1 to the center of gravity of the second optical cell 2', thereby reducing the moment in the direction of gravity that occurs with this mounting point as a fulcrum.

[0058] The specific shape of the second optical cell 2' may be an elongated shape such as a roughly rectangular parallelepiped shape, or may be an elongated shape such as a roughly cubic shape. When the second optical cell 2' has an elongated shape, it is desirable that the second optical cell 2' also stands upright in the connection direction of the gas cell 1.

[0059] Furthermore, the gas analyzer 100 according to the present invention may have multiple optical paths for the laser light that passes through the gas and is guided to the photodetector 7, by using multiple light sources 5 as shown in FIG. 8 or by splitting a single light source 5 using a beam splitter (not shown). In this case, for example, one optical path can be made a long optical path by multiple reflection as in the above embodiment, and the other optical path can be made a short optical path that is shorter than the one optical path without multiple reflection, for example.

[0060] In addition, in the gas analyzer 100 according to the present invention, as shown in FIG. 9(A), as long as the base plate 10 constituting the optical cell 2 is arranged opposite the gas cell 1, the optical cell 2 does not need to be elongated, for example, roughly cubic in shape. According to this configuration, the base plate 10 is disposed opposite the gas cell 1, in other words, the base plate 10 stands upright in the connection direction X between the gas cell 1 and the optical cell 2. Therefore, when the gas cell is attached to a pipe H extending vertically, for example, the distance from the attachment point of the gas cell 1, etc. to the center of gravity of the optical cell 2 is shorter than in the conventional configuration in which the base plate 10 is laid down. This reduces the moment in the direction of gravity generated with this attachment point as a fulcrum, and minimizes optical axis misalignment.

[0061] Furthermore, in the gas analyzer 100 according to the present invention, as long as the elongated optical cell 2 is erected in the connection direction X with the gas cell 1 as shown in FIG. 9(B), the base plate 10 does not necessarily have to face the gas cell 1; for example, it may be placed on the opposite side of the gas cell 1.

[0062] The gas cell 1 may have various shapes such as a roughly rectangular parallelepiped, a roughly cubic, or a roughly cylindrical shape, and the size (length) along the gas flow direction and the direction perpendicular thereto may be changed as appropriate.

[0063] Furthermore, the gas analyzer 100 according to the present invention may be an analyzer that uses, for example, Fourier transform infrared spectroscopy (FTIR) or non-dispersive infrared absorption (NDIR).

[0064] 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. [Industrial Applicability]

[0065] According to the present invention, it is possible to reduce the moment in the direction of gravity that occurs with the attachment point or the like as a fulcrum, thereby minimizing the misalignment of the optical axis as much as possible.

Claims

1. A gas analyzer that analyzes a measurement target component contained in a gas by irradiating the gas with laser light and detecting the laser light that has transmitted through the gas, a gas cell attached to a pipe through which the gas flows and into which the gas is introduced; an elongated optical cell that is connected to the gas cell in a predetermined connection direction and that houses a mirror supported on an elongated surface plate while being disposed on an optical path of the laser light, the optical cell and the base stand upright in the connection direction, a heating mechanism for heating the gas cell and a heat insulating material for covering the gas cell, The gas analyzer further comprises a beam member having one end connected to the optical cell and the other end located inside the heat insulating material and connected to the gas cell, connecting the optical cell and the gas cell.

2. The gas analyzer according to claim 1 , wherein the surface plate is disposed opposite the gas cell.

3. A gas analyzer that analyzes a measurement target component contained in a gas by irradiating the gas with laser light and detecting the laser light that has transmitted through the gas, a gas cell attached to a pipe through which the gas flows and into which the gas is introduced; an optical cell that is connected to the gas cell in a predetermined connection direction and that houses a mirror that is supported by a surface plate while being disposed on an optical path of the laser light, the surface plate is disposed opposite the gas cell, a heating mechanism for heating the gas cell and a heat insulating material for covering the gas cell, The gas analyzer further comprises a beam member having one end connected to the optical cell and the other end located inside the heat insulating material and connected to the gas cell, connecting the optical cell and the gas cell.

4. 4. The gas analyzer according to claim 1, wherein a light source that emits the laser light, a detector that detects the laser light, the mirror on the light-emitting side that guides the laser light emitted from the light source to the gas cell, and the mirror on the light-receiving side that guides the laser light that has passed through the gas to the detector are supported on the base.

5. 2. The gas analyzer according to claim 1, wherein said beam member has a higher thermal insulation property than at least said surface plate.

6. 6. The gas analyzer according to claim 1, further comprising at least two reflecting mirrors that reflect the laser light as the mirror on the light projecting side that guides the laser light to the gas cell.

7. In a configuration including an adjustment mechanism for adjusting the position or attitude of the mirror, The gas analyzer according to claim 1 , wherein an operating portion for operating the adjustment mechanism faces a side opposite to a center portion of the optical cell.

8. 8. The gas analyzer according to claim 1, wherein the gas cell is provided with a pair of reflecting mirrors therein for multiple reflection of the laser light.

9. 9. The gas analyzer according to claim 1, wherein the gas cell is provided in a chamber in which a semiconductor manufacturing process is performed or in a pipe connected to the chamber.

10. a second optical cell that is connected to the gas cell in a predetermined connection direction and that houses a mirror supported by a surface plate while being disposed on an optical path of the laser light; The gas analyzer according to claim 1 , wherein the base of the second optical cell is disposed opposite the gas cell.

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