Concentration measurement device and method for manufacturing concentration measurement device

Abstract

To provide a concentration measurement device capable of appropriately measuring a concentration of gas without causing leakage even when the gas is high-temperature gas.SOLUTION: A concentration measurement device 100 comprises: a first flow path block including a measurement cell 10; a light source 2; a photodetector 4 that receives light passing through the measurement cell; a second flow path block arranged adjacent to the first flow path block; and a gasket member arranged at a flow path connection part between the first flow path block and the second flow path block. The second flow path block has a connection hole including a first hole portion facing the first flow path block and a second hole portion having a larger cross-sectional area and extending from the first hole portion. The second flow path block is fixed by pressing a step surface of the connection hole with an enlarged-diameter portion of a block fixing member arranged in the connection hole. A length of the first hole portion is shorter than a distance from a block connection surface to a central axis of a pressure sensor.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a concentration measuring device and a method for manufacturing the same, and more particularly to a concentration measuring device that measures the concentration of a fluid based on the intensity of light passing through a measurement cell, and a method for manufacturing the same. [Background technology]

[0002] Conventionally, there has been known a concentration measuring device that is incorporated in a gas supply line that supplies a source gas formed from a liquid material or a solid material such as an organic metal (MO) to a semiconductor manufacturing device, that is, a so-called in-line concentration measuring device. The in-line concentration measuring device is configured to measure the concentration of the gas flowing through the gas supply line.

[0003] This type of concentration measuring device measures absorbance by shining light of a specific wavelength from a light source through an entrance window into a measurement cell in which a fluid flows, and receiving the transmitted light that passes through the measurement cell with a light receiving element. The concentration of the measured fluid can be calculated from the measured absorbance according to the Beer-Lambert law.

[0004] In this specification, various transmitted light detection structures used to detect the concentration of a measurement fluid introduced therein are broadly referred to as measurement cells. Measurement cells include not only cell structures that are branched off from a gas supply line and arranged separately, but also in-line transmitted light detection structures that are provided midway along a gas supply line.

[0005] Patent Document 1 discloses a reflection-type concentration measuring device that is provided with a reflecting member at the end of a measurement cell and detects the concentration of a fluid flowing through the measurement cell based on the absorbance of light that has traveled back and forth through the measurement cell. In such a reflection-type concentration measuring device, the optical path length can be made relatively long despite its compact form, and therefore improvement in measurement accuracy can be expected.

[0006] Patent documents 2 and 3 disclose a concentration measuring device that is provided with a pressure sensor downstream of a measurement cell, and that can obtain the absorbance of the measurement fluid from the output of a photodetector and calculate the fluid concentration using the output of the pressure sensor as well. In particular, as disclosed in Patent document 4, when measuring the concentration of a gas, the concentration of the gas to be measured in a mixed gas can be detected with improved accuracy by calculating the concentration taking into account the pressure and temperature. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. 2018 / 021311 [Patent Document 2] JP 2018-25499 A [Patent Document 3] International Publication No. 2020 / 066732 [Patent Document 4] International Publication No. 2020 / 158506 Summary of the Invention [Problem to be solved by the invention]

[0008] However, as described in Patent Documents 2 to 4, when measuring the concentration using gas pressure in addition to absorbance, it is necessary to provide a pressure sensor for measuring the pressure of the gas inside the measurement cell. In order to measure the gas pressure inside the measurement cell more accurately, it is preferable to place the pressure sensor as close to the measurement cell as possible. For this reason, in conventional concentration measuring devices, a flow path block for fixing the pressure sensor is placed adjacent to the downstream side of the flow path block constituting the measurement cell.

[0009] However, it was found that in the concentration measuring device described above, gas leakage may occur from the location of the pressure sensor provided in the flow path block. In particular, when measuring the concentration of high-temperature gas, it was found that the possibility of gas leakage occurring around the pressure sensor increases.

[0010] The present invention has been made to solve the above-mentioned problems, and its main object is to provide a concentration measuring device and a manufacturing method thereof that can properly measure the concentration of high-temperature gas while preventing the occurrence of leaks. [Means for solving the problem]

[0011] A concentration measuring device according to an embodiment of the present invention includes a first flow path block in which a measurement cell through which a gas passes is formed, a light source that emits light to be incident on the measurement cell, a photodetector that receives the light that has passed through the measurement cell, and a second flow path block that is disposed adjacent to the first flow path block and carries a pressure sensor that measures the pressure of the gas in the measurement cell. The concentration measuring device has a gasket member sandwiched at a connection portion of a flow path between the first flow path block and the second flow path block, and the second flow path block has a connection hole that extends toward the first flow path block, and the connection hole has a first cross-sectional area of a first hole portion having a cross-sectional area facing the first flow path block, and a second hole portion having a second cross-sectional area larger than the first cross-sectional area and extending outward from the first hole portion, a step surface is formed at the boundary between the first hole portion and the second hole portion, the second flow path block is fixed to the first flow path block by an enlarged portion of a block fixing member arranged in the connection hole pressing the step surface of the connection hole, and a length of the first hole portion of the connection hole is shorter than a distance from a connection surface between the first flow path block and the second flow path block to a central axis of the pressure sensor.

[0012] In one embodiment, a length of the first hole portion of the connection hole is shorter than a distance from a connection surface between the first flow path block and the second flow path block to a sealed end of the pressure sensor.

[0013] In one embodiment, the second flow path block is provided with two of the connection holes, a block fixing member is disposed in each of the connection holes, and a flow path formed inside the second flow path block and extending from the gasket member is disposed so as to overlap with the two connection holes.

[0014] A manufacturing method for the concentration measurement device according to an embodiment of the present invention includes the steps of: preparing the first flow path block, the second flow path block, the gasket member, the block fixing member, and the pressure sensor; fixing the second flow path block to the first flow path block via the gasket member using the block fixing member arranged in the connection hole formed in the second flow path block; and, after the step of fixing the second flow path block to the first flow path block, fixing the pressure sensor to the second flow path block. Effect of the Invention

[0015] According to the concentration measuring device of the embodiment of the present invention, it is possible to appropriately measure the concentration of gas used in semiconductor manufacturing equipment and the like, and also to suppress the occurrence of leaks when the device is installed in a supply line for high-temperature gas. [Brief description of the drawings]

[0016] [Figure 1] 1 is a schematic diagram showing a configuration of a concentration measuring device according to an embodiment of the present invention. [Diagram 2] FIG. 4 is a cross-sectional view showing a more specific example of the configuration of a high-temperature gas unit of the concentration measuring device according to the embodiment of the present invention. [Diagram 3] FIG. 2 is a perspective view showing the appearance of the high-temperature gas unit. [Figure 4] FIG. 4 is a perspective view showing a cross section of the hot gas unit shown in FIG. 3 with the top cut away. [Diagram 5] 1A and 1B are diagrams showing the positional relationship between two adjacent flow passage blocks and their fixing members in a high-temperature gas unit, where (a) is a conceptual diagram as seen from the side, and (b) is a conceptual diagram as seen from above. [Figure 6] FIG. 13 is a schematic diagram showing another embodiment of the arrangement relationship between two adjacent flow passage blocks and their fixing members in the high-temperature gas unit, as viewed from the side. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following embodiment.

[0018] 1 shows a concentration measuring device 100 according to an embodiment of the present invention. The concentration measuring device 100 is incorporated in-line into a gas supply line used in a semiconductor manufacturing system or the like, and is used to measure the concentration of gas G flowing through a flow path. The gas supply line provided with the concentration measuring device 100 is used to supply high-temperature gas generated by a vaporizer or the like as a raw material gas to a process chamber of a semiconductor manufacturing device, for example.

[0019] Examples of the source gas include HCDS (Si2Cl6), or organometallic materials such as TEOS (tetraethyl orthosilicate), TMGa (trimethylgallium), and TMAl (trimethylaluminum). These materials are liquid at room temperature and can be vaporized by heating to, for example, about 150°C to 200°C. The generated source gas is then vaporized in a process chamber, for example, by depositing a silicon nitride film (SiN x It is used to form insulating films such as silicon oxide films (SiO2 films) and silicon dioxide films (SiO2 films).

[0020] The concentration measuring device 100 of this embodiment includes a high-temperature gas unit 50A that is incorporated in a gas supply line, and an electric unit 50B that is disposed apart from the high-temperature gas unit 50A. The high-temperature gas unit 50A is provided with a pressure sensor 18 for measuring the pressure of the gas G in the measurement cell 10. The electric unit 50B is provided with a light source 2, a measurement light detector 4, a reference light detector 6, and an arithmetic processing circuit 8. The high-temperature gas unit 50A and the electric unit 50B are optically and electrically connected by an optical fiber cable 5a and a sensor cable 5b.

[0021] The high-temperature gas unit 50A may be heated to, for example, about 100°C to 150°C depending on the type of fluid to be measured, but the electric unit 50B separated from it is typically maintained at room temperature (clean room atmosphere, etc.). Therefore, damage to the electric elements due to heat can be prevented. However, although it is called the high-temperature gas unit 50A in this embodiment, it is not limited to use at high temperatures, and when gas at room temperature or below room temperature is used, it may be used in a state where it does not become hot (is not heated). An external control device configured to transmit a control signal to the concentration measuring device 100 and receive a measurement signal from the concentration measuring device 100 may be connected to the electric unit 50B.

[0022] The high-temperature gas unit 50A is provided with a measurement cell 10 configured to use a flow path extending in the longitudinal direction as an optical path. An optical element member 12 configured so that light from a collimator lens is incident on the inside through a window (light-transmitting plate) in contact with the flow path is disposed at one end of the measurement cell 10. In addition, a reflecting member 14 for reflecting the incident light is disposed at the other end of the measurement cell 10.

[0023] Light from a light source 2 enters the measurement cell 10 via an optical element member 12, and the light reflected by a reflecting member 14 of the measurement cell 10 is guided to a measurement light detector 4 via the optical element member 12. In this specification, light includes not only visible light, but also at least infrared light and ultraviolet light, and may include electromagnetic waves of any wavelength. Moreover, translucency means that the internal transmittance of the light entering the measurement cell 10 is high enough to enable concentration measurement.

[0024] The light incident from the light source 2 to the measurement cell 10 and the light emitted from the measurement cell 10 to the measurement light detector 4 may be guided by a single common optical fiber cable as shown in FIG. 1, or may be guided by separate optical fiber cables via separate paths.

[0025] On the other hand, the electrical unit 50B is provided with a light source 2 that generates light to be incident into the measurement cell 10, a measurement light detector 4 that receives light emitted from the measurement cell 10, a reference light detector 6 that receives reference light from the light source 2, and an arithmetic processing circuit 8 configured to calculate the concentration of the measurement fluid based on a detection signal corresponding to the intensity of the light.

[0026] In this embodiment, the light source 2 is configured using two light-emitting elements 2a and 2b. The light-emitting elements 2a and 2b are configured by elements that emit ultraviolet light of different wavelengths, for example, LEDs that emit light of 280 to 320 nm and light of 340 to 380 nm, respectively. Driving currents of different frequencies are applied to the light-emitting elements 2a and 2b using an oscillation circuit, and frequency analysis (for example, fast Fourier transform or wavelet transform) is performed to measure the intensity of light corresponding to each wavelength component from the detection signal detected by the measurement light detector 4. LDs (laser diodes) can also be used as the light-emitting elements 2a and 2b. A light source of a single wavelength can also be used, in which case the multiplexer and frequency analysis circuit can be omitted. Three or more light-emitting elements may be provided, or the incident light may be generated using only an arbitrary light-emitting element selected from the provided elements. The light emitted by the light-emitting elements may have any wavelength depending on the absorption characteristics of the measurement gas, and may be visible light or infrared light, not limited to ultraviolet light.

[0027] In this embodiment, the measurement light detector 4 and the reference light detector 6 are disposed opposite each other with a beam splitter in between, and a part of the light from the light source 2 is incident on the reference light detector 6, and the detection light from the measurement cell 10 is incident on the measurement light detector 4. As the light receiving elements constituting the measurement light detector 4 and the reference light detector 6, for example, photodiodes or phototransistors are used.

[0028] The arithmetic processing circuit 8 is configured, for example, by circuit elements such as a processor and memory provided on a circuit board, includes a computer program that executes a predetermined calculation based on an input signal, and can be realized by a combination of hardware and software. In the illustrated embodiment, the arithmetic processing circuit 8 is built into the electric unit 50B, but some or all of its components (such as a CPU) may be provided in a device outside the electric unit 50B.

[0029] In the concentration measuring device 100 described above, the optical path length of the light traveling back and forth in the measurement cell 10 can be defined as twice the distance between the surface of the window in front of the optical element member 12 and the surface of the reflecting member 14. In the concentration measuring device 100, the light that is incident on the measurement cell 10 and then reflected by the reflecting member 14 is absorbed by the gas present in the flow path in the measurement cell 10 at a level that depends on the concentration of the gas. The arithmetic processing circuit 8 can measure the absorbance A at the absorption wavelength by frequency analyzing the detection signal from the measurement light detector 4, and can further calculate the gas concentration C from the absorbance A based on the Beer-Lambert law shown in the following formula (1). Aλ=-log 10 (I / I0) = α'LC M

[0030] In the above formula, I0 is the intensity of the incident light entering the measurement cell, I is the intensity of the light passing through the gas in the measurement cell, and α' is the molar absorption coefficient (m 2 / mol), L is the optical path length of the measurement cell (m), C M is the molar concentration (mol / m 3 ) The molar extinction coefficient α' is a coefficient that depends on the substance. Note that, with regard to the incident light intensity I0 in the above formula, the intensity of light detected by the photodetector 24 when there is no light-absorbing gas in the measurement cell 1 (for example, when the measurement cell 1 is filled with a gas that does not absorb ultraviolet light or when the measurement cell is evacuated) may be regarded as the incident light intensity I0.

[0031] As described above, the optical path length L of the measurement cell 10 can be defined as twice the distance between the window and the reflecting member, so that it is possible to obtain twice the optical path length compared to a concentration measuring device having a light entrance window and a light exit window at both ends of the measurement cell. This makes it possible to improve the measurement accuracy despite the miniaturization. Furthermore, in the concentration measuring device 100, light is input and output using only one optical element member 12 provided on one side of the measurement cell 10, so that maintenance is easy and the number of parts can be reduced.

[0032] However, in other embodiments, a transmission type measurement cell may be used instead of the above-mentioned so-called reflection type measurement cell. In the transmission type measurement cell, light is incident from one end of the measurement cell, and light that has passed through the measurement cell is emitted from the other end (without a reflection member). In this case, the light source light and the transmitted light are transmitted by separate optical fibers connected to both ends of the measurement cell.

[0033] Furthermore, in the concentration measuring device 100, the high-temperature gas unit 50A is provided with a pressure sensor 18, which can measure the pressure of the gas G in the measurement cell 10. Therefore, based on the output from the pressure sensor 18, the measured absorbance can be corrected to the absorbance at a predetermined pressure (for example, 1 atmosphere). Then, based on the corrected absorbance, the Beer-Lambert law can be modified to calculate the concentration of the measured fluid, as in the concentration measuring devices described in Patent Documents 3 and 4. In addition, since a temperature sensor 16 is further provided to measure the temperature of the gas flowing through the measurement cell 10, concentration detection can also be performed by further performing correction based on temperature.

[0034] As the pressure sensor 18, for example, a silicon single crystal pressure sensor having a pressure-sensitive diaphragm provided with a strain gauge or a capacitance manometer is used. As the pressure sensor 26, for example, a pressure sensor described in International Publication No. 2022 / 137812 can be used. In addition, as the temperature sensor 16, for example, a thermocouple, a thermistor, or a platinum resistance thermometer is used.

[0035] The concentration measuring device 100 can determine the concentration of the gas flowing through the measuring cell 10, for example, from the following relational expression, also referring to the outputs of the pressure sensor 18 and the temperature sensor 16. Cv = (RT / αLPt)·ln(I0 / I)

[0036] In the above formula, Cv is the concentration (volume %) of the measurement gas in the total gas, α is the absorption coefficient of the measurement gas, Pt is the total pressure that can be measured by the pressure sensor 18, T is the temperature that can be measured by the temperature sensor 16, and R is the gas constant. Also, similar to the Beer-Lambert law, L is the optical path length of the measurement cell, I0 is the incident light intensity, and I is the transmitted light intensity.

[0037] In this manner, the concentration measuring device 100 can determine the concentration of the fluid in the measurement cell 10 based on the output (transmitted light intensity I) of the measurement light detector 4. However, it has been confirmed that when the pressure sensor 18 is used in the high-temperature gas unit 50A, particularly when measuring the concentration of high-temperature gas, gas leakage may occur from the fixing point of the pressure sensor 18.

[0038] This is thought to be because, when the flow path block to which the pressure sensor 18 is fixed is fastened to another flow path block and then the device is aged for use at high temperatures, the stress (distortion) generated when the bolts are fastened to fix the blocks together affects the shape of the fixed portion of the pressure sensor 18. When used at high temperatures, even a slight stress (distortion) has a large effect and is likely to cause a leak. Therefore, in the concentration measuring device 100, measures against leaks are taken to handle high-temperature gas, as described below.

[0039] Fig. 2 is a cross-sectional view showing a configuration example of the high-temperature gas unit 50A, and Fig. 3 is a perspective view showing a configuration example of the high-temperature gas unit 50A. The high-temperature gas unit 50A is composed of a first flow path block BL1 in which the measurement cell 10 is formed, and a second flow path block BL2 arranged adjacent to the first flow path block BL1 and carrying a pressure sensor 18.

[0040] Here, the flow path block is typically a metal block body in which flow paths and fluid storage spaces are formed, and is also referred to as a main body block. The first flow path block BL1 and the second flow path block BL2 are metal blocks made of stainless steel such as SUS316L, and the gas flow paths are formed therein by drilling holes.

[0041] 3 shows a state in which the optical element member 12 (optical fiber cable 5a is omitted) is attached to the first flow path block BL1, and the second flow path block BL2 is shown in a state before the pressure sensor 18 is attached (a state in which the attachment recess 18H is exposed). As will be described later, in a manufacturing method of the high temperature gas unit 50A according to an embodiment, the pressure sensor 18 is fixed to the second flow path block BL2 after the first flow path block BL1 and the second flow path block BL2 are fixed to each other, and the two are temporarily assembled into the state shown in FIG.

[0042] 2, in the first flow path block BL1, a window 13 is disposed in front of the optical element member 12 to form a measurement cell 10, and the window 13 is fixed to the first flow path block BL1 by a pressing member 11. In addition, the reflecting member 14 is fixed to the first flow path block BL1 by a pressing member 15. The window 13 and the reflecting member 14 are fixed via a gasket to improve sealing performance.

[0043] For example, a sapphire plate is used as the window 13. The window 13 may be arranged at a slight inclination (for example, 1° to 5°) from a plane perpendicular to the central axis of the measurement cell 10, which can suppress the influence of surface reflected light on the measurement.

[0044] The reflecting member 14 may be, for example, a sapphire plate having an aluminum layer formed as a reflecting layer on the rear surface thereof by sputtering. However, the reflecting member 14 may have a configuration in which a reflecting mirror is disposed on the rear surface of the sapphire plate. The reflecting member 14 may also include a dielectric multilayer film as a reflecting layer, and the use of the dielectric multilayer film allows selective reflection of light in a specific wavelength range (for example, near ultraviolet light). The dielectric multilayer film is composed of a laminate of multiple optical coatings having different refractive indices (for example, a laminate of a high refractive index thin film and a low refractive index thin film), and by appropriately selecting the thickness and refractive index of each layer, it is possible to reflect or transmit light of a specific wavelength. In addition, since the dielectric multilayer film can reflect light at any ratio, it is possible to substitute the reference light detector 6 provided in the electric unit 50B shown in FIG. 1 by transmitting a part of the light (for example, 10%) and detecting the transmitted light with a light receiving element.

[0045] On the other hand, the pressure sensor 18 is fixed to the upper surface of the second flow path block BL2 (next to the optical element member 12) in such a manner that the pressure sensor 18 is pressed by the bonnet 19 while the sealing performance is enhanced by the gasket 18G. The pressure sensor 18 can be fixed to the second flow path block BL2 by rotating the bonnet 19 having a screw on its outer periphery. The pressure sensor 18 may be disposed on the lower surface (next to the reflecting member 14) or on the side surface of the second flow path block BL2.

[0046] A gasket member 20 is disposed at the flow path connection between the first flow path block BL1 and the second flow path block BL2. This can suppress the occurrence of leakage of gas flowing through the flow path at the connection surface BLS between the first flow path block BL1 and the second flow path block. The gasket member 20 is usually made of metal (e.g., SUS316L) or resin (e.g., PCTFE (polychlorotrifluoroethylene)), and is sandwiched at the connection between the first flow path block BL1 and the second flow path block BL2 to ensure the sealing of the connection of the flow paths.

[0047] In this embodiment, the first flow path block BL1 and the second flow path block BL2 are fixed to each other by inserting block fixing members, typically bolts, into connecting holes H extending from an end face of the second flow path block BL2 toward the first flow path block BL1, and passing them through receiving holes provided in the first flow path block BL1, as shown in Fig. 3. As shown in Fig. 3, in this embodiment, the block fixing members are disposed in each of two connecting holes H provided in parallel to sandwich the flow paths inside the second flow path block BL2. However, as long as there is no problem with the fixing, the number of connecting holes H may be one or three or more.

[0048] Fig. 4 is a view of the upper half of the high-temperature gas unit 50A in Fig. 3 cut at the height of the connection hole H. As shown in Fig. 4, the connection hole H provided in the second flow path block BL2 is composed of a first hole portion H1 having a first cross-sectional area facing the first flow path block BL1, and a second hole portion H2 having a larger diameter (larger second cross-sectional area) that extends outward as an extension of the first hole portion H1. A step surface HS (bottom surface of the second hole portion H2) is formed at the boundary between the first hole portion H1 and the second hole portion H2.

[0049] The direction in which the flow path blocks are lined up is sometimes referred to as the horizontal direction, and the direction perpendicular to this on the plane of the paper in Fig. 2 is sometimes referred to as the vertical direction or up-down direction. However, it goes without saying that the actual horizontal and vertical directions may differ depending on the attitude and mounting direction of the high-temperature gas unit 50A. Also, for convenience, the surface parallel to the block connection surface is sometimes referred to as the end surface of the block, the surface on which elements, etc. are mounted is sometimes referred to as the upper and lower surfaces of the block, and the lateral surface between the upper and lower surfaces (the surface perpendicular to the end surface) is sometimes referred to as the side surface of the block.

[0050] 4, in the high temperature gas unit 50A of this embodiment, the length La of the first hole portion H1 in the connection hole H is relatively short, in other words, the depth of the countersink of the connection hole H (the length of the second hole portion H2) is relatively deep. Here, the countersink refers to a hole in an enlarged diameter portion, which is a portion that is dug down with a larger diameter so that the head of a fixing member such as a screw or bolt to be installed does not protrude.

[0051] In this embodiment, the block fixing member 22 is a hexagon socket bolt having an enlarged diameter portion (or head) 22H, and its tip is inserted into a receiving hole formed in the first flow path block BL1. In this embodiment, a screw is formed on the outer periphery of the insertion portion of the block fixing member 22, and a screw is also formed in the receiving hole. Therefore, by rotating the enlarged diameter portion 22H, the block fixing member 22 can be advanced in the direction of the first flow path block BL1. Although not shown, a washer may be disposed between the enlarged diameter portion 22H and the step surface HS of the connection hole H.

[0052] After the enlarged diameter portion 22H comes into contact with the step surface HS, the enlarged diameter portion 22H can be further rotated to press the step surface HS, thereby firmly fixing the second flow path block BL2 to the first flow path block BL1. This makes it possible to prevent gas leakage from the connection surface BLS even in a configuration in which the gasket member 20 is disposed at the block boundary.

[0053] However, a relatively large stress is generated in the second flow path block BL2 due to the fastening of the block fixing member 22. In contrast, in the concentration measuring device 100 of this embodiment, by deeply boring the countersink as described above, the stress generated in the second flow path block BL2 when the second flow path block BL2 is fixed to the first flow path block BL1 by the block fixing member 22 is concentrated in the portion near the first flow path block BL1. This makes it possible to suppress the generation of stress and distortion near the mounting recess 18H of the pressure sensor 18 and prevent the occurrence of gas leakage from the fixing point of the pressure sensor 18.

[0054] 5(a) and (b) are diagrams for explaining a manner in which the second flow path block BL2 is fixed to the first flow path block BL1 using the block fixing member 22. In Fig. 5(a), the flow path portion is indicated by a dashed line, and the pressure sensor 18, the block fixing member 22, etc. are indicated by a solid line. However, these are conceptual diagrams for explaining the positional relationship, and for example, the block fixing member 22 shown in Fig. 5(b) is not actually visible from above, but merely shows the arrangement inside the flow path block.

[0055] 5(a) and (b), in this embodiment, the length La of the first hole portion H1 formed in the second flow path block BL2 is set to be shorter than the distance Lb from the connection surface BLS between the first flow path block BL1 and the second flow path block BL2 to the central axis 18x of the pressure sensor 18. Also, the connection hole H and the horizontal flow path extending from the gasket member 20 (see FIGS. 2 and 4) formed inside the second flow path block BL2 are arranged to overlap when viewed from the side. In this embodiment, the central axis 18x of the pressure sensor 18 coincides with the central axis of the flow path extending in the longitudinal direction formed in the second flow path block BL2.

[0056] In this way, by providing the step surface HS (i.e., the pressing surface of the block fixing member 22) closer to the connection surface BLS than the central axis 18x of the pressure sensor 18, the stress generated when the block fixing member 22 is fastened is prevented from spreading over the entire fixing point of the pressure sensor 18. Therefore, the occurrence of distortion at the fixing point of the pressure sensor 18 can be suppressed, and the occurrence of leaks can be prevented. In addition, since the sides of the gasket member 20 are fixed by the block fixing member 22, the sealing performance can be efficiently improved by fastening the block fixing member 22. Therefore, the occurrence of stress due to excessive fastening is prevented, and the occurrence of distortion and leaks at the fixing point of the pressure sensor 18 can be prevented.

[0057] Since the block fixing member 22 only needs to be able to firmly hold the gasket member 20 between the blocks, there is no need to increase the length of the fastening between the flow path blocks as long as the sealing performance is ensured by the gasket member 20. For this reason, the countersink is intentionally made deep to prevent leakage from the fixing point of the pressure sensor 18, thereby reducing the probability of leakage occurring throughout the high temperature gas unit 50A.

[0058] In addition, the pressure sensor 18 may be fixed to the mounting surface of the second flow path block BL2 by sandwiching an annular gasket 18G (see Figure 2) between them to ensure sealing, and the outer peripheral surface of this gasket 18G is defined as the sealed end of the pressure sensor 18.

[0059] 6, the length La of the first hole portion H1 may be set to be shorter than the distance Lc from the connection surface BLS to the seal end of the pressure sensor 18. In this way, by bringing the step surface HS of the hole as close as possible to the connection surface BLS of the block, it is possible to more effectively prevent the stress generated when the block fixing member 22 is fastened from distorting the periphery of the pressure sensor 18.

[0060] The length La of the first hole portion H1 may be set to be shorter than the distance from the connecting surface BLS of the block to the flow passage formed in the second flow passage block BL2 and extending in the longitudinal direction.

[0061] Next, a method for manufacturing the concentration measuring device 100 described above that can further reduce the occurrence of gas leakage from the fixing point of the pressure sensor 18 will be described.

[0062] In connecting flow path blocks, elements such as a pressure sensor are usually fixed to a flow path block before connecting an adjacent flow path block. However, in the manufacturing method of the concentration measuring device 100 according to the present embodiment, the pressure sensor 18 is fixed to the second flow path block BL2 after the second flow path block BL2 is fixed to the first flow path block BL1.

[0063] More specifically, first, a first flow path block BL1 in which the measurement cell 10 is formed is prepared. Next, a second flow path block BL2 in a state in which the pressure sensor 18 is not fixed is prepared, and this is firmly fixed to the first flow path block BL1 by the block fixing member 29 using the connection hole H with the gasket member 20 interposed therebetween. At this time, stress may be generated in the second flow path block BL2 due to the fixing by the block fixing member 22, but since the step surface HS is formed at a position relatively close to the first flow path block BL1 as described above, it is possible to reduce the occurrence of distortion at the fixing point of the pressure sensor 18.

[0064] Then, after the second flow path block BL2 is fixed to the first flow path block BL1, the pressure sensor 18 is fixed to the second flow path block BL2. The pressure sensor 18 can be fixed by disposing the sensor body in the recess of the second flow path block BL2 via the gasket 18G, and then rotating the bonnet 19. A gasket guide ring may be provided around the gasket 18G. A co-rotation prevention washer may be sandwiched between the bonnet 19 and the sensor body. The screw formed on the outer peripheral surface of the bonnet 19 is engaged with the screw formed on the inner peripheral surface of the recess of the second flow path block BL2, and the bonnet 19 is rotated, so that the sensor body can be firmly fixed to the second flow path block BL2 with high sealing performance while pressing the gasket 18G.

[0065] It was found that the method of fixing the pressure sensor 18 to the second flow path block BL2 that has already been fixed to the first flow path block BL1 in this way can further suppress the occurrence of gas leakage from the attachment point of the pressure sensor 18. The reason for this is thought to be that even if some distortion occurs in the second flow path block BL2 before the pressure sensor 18 is attached, the gasket will be appropriately deformed during the process of fixing the pressure sensor 18, and the sealing performance will be restored. Therefore, the manufacturing method in which the pressure sensor 18 is attached later can more effectively prevent the occurrence of gas leakage.

[0066] Although the embodiment of the present invention has been described above, various modifications are possible. For example, the above describes a connection hole H that is configured by a first hole portion H1 having a first diameter and a second hole portion H2 having a larger second diameter, but is not limited to this. The second hole portion H2 does not necessarily have to have an elongated hole shape, and may be, for example, a groove or a recess formed in the side surface of the second flow path block BL2. The formed groove or recess does not have to reach the downstream end face of the second flow path block BL2. As long as the cross-sectional area of ​​the second hole portion H2 is larger than the cross-sectional area of ​​the first hole portion H1 and a step surface HS is formed at the boundary between them, the shape of the second hole portion H2 may be arbitrary. [Industrial Applicability]

[0067] The flow rate control device and vaporization supply device according to the embodiments of the present invention are incorporated into a gas supply system of a semiconductor manufacturing facility or the like and are appropriately used to perform flow rate control over a wide control range. [Explanation of symbols]

[0068] 2 light source 4. Measurement Photodetector 6 Reference Photodetector 8. Arithmetic Processing Circuit 10 Measuring Cell 12 Optical element materials 14 Reflective material 16 Temperature Sensor 18 Pressure Sensor 20 Gasket material 22 Block fixing member 22H Enlarged diameter part of block fixing member (head) 50A Hot Gas Unit 50B Electrical Unit 100 Concentration measuring device BL1 First flow path block BL2 Second flow path block H Connection hole H1 1st hole part H2 2nd hole part HS step surface

Claims

1. a first flow path block in which a measurement cell through which a gas passes is formed; a light source that emits light to be incident on the measurement cell; a photodetector that receives light that has passed through the measurement cell; a second flow path block disposed adjacent to the first flow path block and carrying a pressure sensor for measuring the pressure of the gas in the measurement cell; a gasket member is sandwiched at a connection portion of a flow path between the first flow path block and the second flow path block, the second flow path block has a connection hole extending toward the first flow path block, the connection hole including a first hole portion having a first cross-sectional area and facing the first flow path block, and a second hole portion having a second cross-sectional area larger than the first cross-sectional area and extending outward from the first hole portion, a step surface being formed at a boundary between the first hole portion and the second hole portion, the second flow path block is fixed to the first flow path block by pressing the step surface of the connection hole with an enlarged diameter portion of a block fixing member disposed in the connection hole, a length of the first hole portion of the connection hole is shorter than a distance from a connection surface between the first flow path block and the second flow path block to a central axis of the pressure sensor.

2. 2. The concentration measuring device according to claim 1, wherein a length of the first hole portion of the connection hole is shorter than a distance from a connection surface between the first flow path block and the second flow path block to a sealed end of the pressure sensor.

3. 3. The concentration measuring device according to claim 1, wherein the second flow path block is provided with two of the connection holes, a block fixing member is arranged in each of the connection holes, and a flow path formed inside the second flow path block and extending from the gasket member is arranged so as to overlap with the two connection holes.

4. A method for manufacturing the concentration measuring device according to claim 1 or 2, comprising the steps of: preparing the first flow path block, the second flow path block, the gasket member, the block fixing member, and the pressure sensor; a step of fixing the second flow path block to the first flow path block with the gasket member interposed therebetween, using the block fixing member disposed in the connection hole formed in the second flow path block; a step of fixing the pressure sensor to the second flow path block after the step of fixing the second flow path block to the first flow path block; A method for manufacturing a concentration measuring device, comprising:

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