Particle measurement device, particle measurement system, and particle measurement method

Abstract

This particle measurement system comprises a light source, a detection unit, a measurement unit, and a flow rate control unit. The light source is configured to emit light toward a fluid flowing through a pipe under reduced pressure connected to a processing device. The detection unit is configured to detect scattered light due to scattering by particles floating in the fluid passing through an area irradiated with the light in the pipe. The measurement unit is configured to measure the count of the particles on the basis of the result of the detection of the scattered light. The flow rate control unit is configured to maintain a section inside the pipe downstream of the irradiated area at a lower pressure than a section inside the pipe upstream of the irradiated area to cause gas at a flow rate for adjusting the rate of the fluid passing through the irradiated area to flow into the downstream section inside the pipe.

Description

Particle Measuring Device, Particle Measuring System, and Particle Measuring Method

[0001] The present disclosure relates to a particle measuring device, a particle measuring system, and a particle measuring method.

[0002] For example, Patent Document 1 discloses a processing apparatus that generates an atmosphere in which the air or gas in a processing chamber is exhausted by a vacuum pump and performs a process related to semiconductor device manufacturing on a workpiece in that atmosphere, and is attached to an exhaust pipe connecting an exhaust port of the processing chamber and the vacuum pump, and measures the number of particles contained in the exhaust gas.

[0003] For example, Patent Document 2 discloses a particle monitoring system for detecting particles in a substrate processing apparatus having a housing chamber that houses a substrate and performs processing, an exhaust device that discharges and depressurizes the gas in the housing chamber, and an exhaust pipe that communicates the housing chamber and the exhaust device, the particle monitoring system including a laser light oscillation device that irradiates laser light toward the exhaust pipe, a light receiving device that receives scattered light or attenuated light of the laser light by the particles flowing in the exhaust pipe and having a focus on the laser light, and a particle converging device that converges the particles toward the focus, and the particle converging device having a gas passage portion that allows the gas to pass from the upstream to the downstream of the exhaust pipe.

[0004] Japanese Patent Application Laid-Open No. 2001-059808, Japanese Patent Application Laid-Open No. 2008-175590

[0005] The present disclosure provides a particle measuring device, a particle measuring system, and a particle measuring method that can improve the measurement sensitivity and detection rate of particles floating in a fluid passing through a pipe.

[0006] One aspect of this disclosure provides a particle measurement system. The particle measurement system comprises a light source, a detection unit, a measurement unit, and a flow velocity control unit. The light source is configured to irradiate light onto a fluid flowing through a piping under reduced pressure, connected to a processing device. The detection unit is configured to detect scattered light scattered by particles suspended in the fluid passing through the light-irradiated area in the piping. The measurement unit is configured to measure the particle count based on the detection results of the scattered light. The flow velocity control unit is configured to allow a gas flow rate to flow into the downstream piping, where the pressure in the piping downstream of the irradiation area is lower than in the piping upstream of the irradiation area, thereby adjusting the velocity of the fluid passing through the irradiation area.

[0007] According to this disclosure, the measurement sensitivity and detection rate of particles suspended in a fluid passing through a pipe can be improved.

[0008] Figure 1 shows an example of a particle measurement system according to the first embodiment. Figure 2 is a diagram illustrating laser light irradiation and scattered light reception. Figure 3 shows an example of the configuration of a particle measurement device. Figure 4 shows an example of experimental results for particle count. Figure 5 shows an example of a particle measurement system according to the second embodiment. Figure 6 is a flowchart showing an example of a particle measurement method according to one embodiment.

[0009] Embodiments of the particle measuring apparatus, particle measuring system, and particle measuring method disclosed herein will be described in detail below with reference to the drawings. It should be noted that these embodiments do not limit the particle measuring apparatus, particle measuring system, and particle measuring method described herein, and the following embodiments can be appropriately combined within the scope of maintaining consistency between the various configurations and processing details of the disclosure.

[0010] Furthermore, the diagrams referenced below are schematic representations for illustrative purposes. Therefore, details may be omitted, and the dimensional proportions may not necessarily match those of reality.

[0011] [First Embodiment] A particle measurement system according to the first embodiment of the present disclosure will be described with reference to Figures 1 and 2. Figure 1 is a diagram showing an example of a particle measurement system according to the first embodiment. Figure 2 is a diagram for explaining the irradiation of laser light and the reception of scattered light.

[0012] The particle measurement system 100 includes a particle measurement device 30. The particle measurement device 30 is attached to a pipe 12 connecting the processing device 10 and the exhaust device 11, and measures particles suspended in the fluid flowing through the pipe 12. Note that the configuration of the particle measurement system 100 and particle measurement device 30 shown in Figure 1 is merely an example, and any configuration can be adopted for the particle measurement system 100 and particle measurement device 30 as long as the desired processing can be performed. The processing device 10 may be, for example, a device that processes substrates such as semiconductor wafers and glass substrates with processing gas supplied inside. In this case, the processing device 10 performs processing such as film deposition and etching on the substrate. The processing device 10 may also be a device that generates plasma from the processing gas using high-frequency power or the like and performs plasma processing on the substrate. The particle measurement device 30 may include, for example, a pressure gauge 13.

[0013] The exhaust device 11 is, for example, a pump, which exhausts the gas inside the processing device 10 via the piping 12. As a result, the inside of the processing device 10 and the piping 12 are controlled to a reduced pressure. The piping 12 carries a fluid, such as exhaust gas, from the processing device 10 to the exhaust device 11 under reduced pressure.

[0014] The fluid in the pipe 12 contains particles such as reaction products generated during substrate processing performed by the processing device 10. The amount of particles in the pipe 12 correlates with the contamination level of the processing device 10. Therefore, the particle measurement system 100 according to the first embodiment measures the particles in the pipe 12 using the particle measurement device 30.

[0015] The particle measuring device 30 includes a light source 31, a light-receiving element 32, a gas inflow mechanism 33, and a monitor control unit 34. Optical windows 15 and 16 are provided on the side wall of the pipe 12. On the outside of the pipe 12, the light source 31 is provided so as to face the optical window 15. Optical window 15 is a window through which light from the light source 31 passes into the pipe 12. Optical window 16 is a window through which scattered light from inside the pipe 12 passes and reaches the light-receiving element 32. The light source 31 is configured to irradiate light toward a fluid flowing through the pipe 12 under reduced pressure, which is connected to the processing device 10. The light irradiated by the light source 31 may be laser light. The optical windows 15 and 16 are made of a material that is transparent to light from the light source 31. The optical windows 15 and 16 may be made of, for example, quartz through which laser light c can pass. The light source 31 may irradiate light in a direction that crosses the pipe 12 perpendicularly or obliquely. In the example shown in Figure 2, the light source 31 emits a laser beam c with a vertical width of 3 mm in the X-axis direction, which is perpendicular to the pipe 12. However, the light source 31 is not limited to this, and may emit light in a direction that diagonally crosses the pipe 12. The shaded area within the pipe 12 shown in Figure 2 is the area through which the laser beam c passes, and will be referred to as the "irradiation area 12c" in the following explanation. In the example in Figure 2, if the cross-section of the pipe 12 is circular, the irradiation area 12c is a disc-shaped area with a width of 3 mm.

[0016] The irradiation of laser light c and the reception of scattered light d will be explained using particles P suspended in the fluid flowing through pipe 12, schematically shown in Figure 2. When particles P pass through the irradiation area 12c of laser light c, a portion of the laser light c is scattered by particles P. The light-receiving element 32 detects this scattered light d. The light-receiving element 32 is positioned outside the irradiation area 12c of pipe 12 irradiated with laser light c, but at a position where scattered light d can be received. In Figure 2, the light-receiving element 32 is shown diagonally above the irradiation area 12c for convenience, but it may be placed at any position where it does not directly receive the laser light c but can receive scattered light d. For example, as long as this positional condition is met, the light-receiving element 32 may be placed in the Y direction perpendicular to the irradiation direction (X direction) of the laser light c. The Y direction is the depth direction of the paper and is perpendicular to the X direction. The light-receiving element 32 is an example of a detection unit configured to detect scattered light scattered by particles floating in the fluid passing through the light-irradiated area 12c inside the pipe 12.

[0017] In the reduced-pressure piping 12, the fluid velocity is very high. As the fluid velocity increases, the time each particle spends within the irradiation area 12c decreases. This reduces the number of scattered photons, meaning the scattering intensity decreases, and particles that pass through the irradiation area 12c may not be counted. This leads to a problem of reduced particle measurement sensitivity and detection rate.

[0018] To solve these problems, the particle measuring device 30 introduces a predetermined flow rate of gas into the piping 12 from the gas inflow mechanism 33. The explanation continues by distinguishing the piping 12 into piping 12a upstream of the irradiation area 12c and piping 12b downstream of the irradiation area 12c. The gas inflow mechanism 33 is connected to the downstream piping 12b near the particle measuring device 30 and introduces a predetermined flow rate of gas into the downstream piping 12b to adjust the velocity of the fluid passing through the irradiation area 12c. The gas inflow mechanism 33 may introduce any gas, such as air, inert gas, or dry air, except for gases that react with the fluid flowing through the piping 12. As a result, the exhaust velocity of the fluid in piping 12b by the exhaust device 11 appears to worsen, the pressure inside piping 12b increases, and the velocity of the fluid passing through the irradiation area 12c decreases. As a result, the time that particles stay in the irradiation area 12c increases.

[0019] Based on the above, the particle measuring device 30 adjusts the flow rate of gas flowing from the gas inlet mechanism 33 into the piping 12b so that sufficient scattering intensity is obtained for counting particles that have passed through the irradiation area 12c. As a result, the particle measuring device 30 can reliably count particles that have passed through the irradiation area 12c, and the measurement sensitivity and detection rate of particles can be improved.

[0020] Figure 3 shows an example of the configuration of a particle measuring device. As shown in Figure 3, the monitor control unit 34 includes a measurement unit 35, a flow velocity control unit 36, a measurement unit 37, a storage unit 38, and a display unit 39.

[0021] The measurement unit 35 is configured to measure the particle count based on the detection result of scattered light d by the light-receiving element 32. Hereinafter, the particle count measured based on the detection result of scattered light d by the light-receiving element 32 will be referred to as the "particle count."

[0022] The measurement unit 35 acquires the amount of scattered light d per unit time, the peak value of scattered light d per unit time, the cumulative value of the detected scattered light, etc., as detection results of scattered light d by the light receiving element 32, and measures the particle count based on these detection results.

[0023] For example, the measurement unit 35 may add 1 to the particle count if scattered light d is detected at each particle measurement interval. The measurement unit 35 may also add 1 to the particle count if a peak above a preset threshold is detected in the scattered light d at each particle measurement interval. However, the measurement unit 35 is not limited to these methods and can measure the particle count using various particle count measurement methods, such as methods using image processing technology.

[0024] The particle count does not have to be the particle number itself, as long as it is a value that correlates with the number of particles in the particle. The measurement unit 35 may measure multiple particle counts over time in an environment where particles in the piping 12 connected to the same processing device 10 are measured under the same measurement conditions. The measurement unit 35 may then determine the contamination status inside the processing device 10 based on the relative changes of the multiple particle counts measured over time. The relative changes such as the difference between multiple particle counts measured over time are an example of a value that correlates with the number of particles in the particle.

[0025] The storage unit 38 stores multiple particle counts. The display unit 39 displays the measurement results from the measurement unit 35. The display unit 39 may display the particle count or the result of determining the contamination status inside the processing device 10. In addition, the display unit 39 may display a message prompting cleaning inside the processing device 10 as a result of determining the contamination status inside the processing device 10.

[0026] The flow velocity control unit 36 ​​controls the gas inflow mechanism 33 to ensure that the pressure inside the pipe 12b downstream of the irradiation area 12c is lower than that inside the pipe 12a upstream of the irradiation area 12c, and to introduce gas at a flow rate that adjusts the fluid velocity passing through the irradiation area 12c into the downstream pipe 12b.

[0027] When the flow velocity control unit 36 ​​introduces a predetermined flow rate of gas into the downstream pipe 12b, the exhaust velocity of the fluid in pipe 12b by the exhaust device 11 appears to worsen, causing the pressure inside pipe 12b to rise. At this time, if the pressure inside the downstream pipe 12b becomes higher than that inside the upstream pipe 12a, the fluid will flow back from pipe 12b to pipe 12a, making it impossible to accurately measure the particle count. Therefore, the flow velocity control unit 36 ​​controls the flow rate of the gas introduced into pipe 12b from the gas inflow mechanism 33 so as to slow down the velocity of the fluid passing through the irradiation area 12c without causing backflow of the fluid.

[0028] The measuring unit 37 is configured to measure the pressure or fluid velocity in the upstream pipe 12a. As shown in Figure 1, the pressure gauge 13 is connected to the pipe 12a upstream of the irradiation area 12c. A pressure control valve 14 is also installed in the pipe 12a upstream of the pressure gauge 13. Therefore, the pressure gauge 13 is installed in the pipe 12a on the particle measuring device 30 side of the pressure control valve 14. The pressure control valve 14 controls the pressure inside the processing device 10 to a reduced pressure state by adjusting the valve opening. The pressure gauge 13 detects the pressure inside the pipe 12a. The measuring unit 37 measures the pressure inside the pipe 12a using the pressure gauge 13.

[0029] The measuring unit 37 may calculate the fluid velocity in pipe 12a from the pressure detected by the pressure gauge 13, based on Boyle's Law and Charles's Law, using parameters such as the pressure and volumetric flow rate in pipe 12a, the pressure and volumetric flow rate of the gas supplied to the processing device 10, and the cross-sectional area of ​​pipe 12a. The flow velocity control unit 36 ​​may control the flow rate of the gas flowing into the downstream pipe 12b based on the pressure or fluid velocity in pipe 12a obtained from the measuring unit 37.

[0030] The control unit 20 processes computer-executable instructions to be executed by the processing unit 10. The control unit 20 may be configured to control each element of the processing unit 10 to execute various processes. In one embodiment, part or all of the control unit 20 may be included in the processing unit 10. The control unit 20 may include a processing unit, a storage unit, and a communication interface (none of which are shown). The control unit 20 is implemented, for example, by a computer. The processing unit may be configured to perform various control operations by reading a program from the storage unit and executing the read program. This program may be stored in the storage unit in advance, or it may be obtained via a medium when needed. The obtained program is stored in the storage unit and read from the storage unit and executed by the processing unit. The medium may be various storage media readable by a computer, or it may be a communication line connected to a communication interface. The processing unit may be a CPU (Central Processing Unit). The storage unit may include RAM (Random Access Memory), ROM (Read Only Memory), HDD (Hard Disk Drive), SSD (Solid State Drive), or a combination thereof. The communication interface communicates with the processing unit 10 via a communication line such as a LAN (Local Area Network).

[0031] The monitor control unit 34 of the particle measuring device 30 may include a processing unit, a storage unit, and a communication interface (none of which are shown), and may be implemented by a computer, for example. The monitor control unit 34 and the control unit 20 may work together to measure particles inside the pipe 12.

[0032] As described above, the particle measuring device 30 can improve the measurement sensitivity and detection rate of particles suspended in the fluid passing through the pipe 12 by introducing a predetermined flow rate of gas into the downstream pipe 12b to adjust the velocity of the fluid passing through the irradiation area 12c.

[0033] [Experimental Results] Figure 4 shows an example of experimental results for particle count. The horizontal axis of Figure 4 shows the pressure inside the pipe 12a measured by the pressure gauge 13, and the vertical axis shows the particle count.

[0034] In the experiment, the measurement unit 35 measured the particle count when 30 and 50 slm of atmospheric air were introduced from the gas inlet mechanism 33, respectively, while the pressure control valve 14 was controlled to a constant opening, such as fully open, and when no atmospheric air was introduced from the gas inlet mechanism 33. In the experiment, the measurement unit 35 measured the particle count after the pressure and fluid velocity in the piping 12a had stabilized.

[0035] In the experimental results shown in Figure 4, point A0 indicates the particle count against the pressure in pipe 12a when no air is introduced from the gas inlet mechanism 33. Point A30 indicates the particle count against the pressure in pipe 12a when 30 slm of air is introduced from the gas inlet mechanism 33. Point A50 indicates the particle count against the pressure in pipe 12a when 50 slm of air is introduced from the gas inlet mechanism 33.

[0036] As indicated by point A0, when no air was introduced from the gas inlet mechanism 33, the measurement unit 35 measured a particle count of 0 or a value close to 0. In contrast, the particle count measured by the measurement unit 35 increased as the flow rate of air introduced from the gas inlet mechanism 33 increased. In other words, the experimental results showed that introducing air into the piping 12b downstream of the irradiation area 12c improved the accuracy of particle measurement.

[0037] The flow velocity control unit 36 ​​may control the flow rate of the gas introduced into the piping 12b so that the particle count exceeds a preset threshold. The preset threshold may be 0 or a value greater than 0. If the time that particles stay in the irradiation area 12c becomes short and sufficient scattering intensity is not obtained to count the particles that have passed through the irradiation area 12c, the measurement unit 35 will not be able to count the particles that have passed through the irradiation area 12c, and the particle count will become 0 or approach 0. Therefore, the flow velocity control unit 36 ​​controls the flow rate of the gas introduced into the piping 12b so that the particle count is 0 or exceeds a preset threshold. As a result, the measurement unit 35 can reliably count the particle count from the initial stage of particle measurement, and the measurement sensitivity and detection rate of the particle count can be improved.

[0038] The display unit 39 may display a graph of Figure 4 showing the correlation between the pressure inside the piping 12a and the flow rate of the gas flowing in from the gas inflow mechanism 33. The display unit 39 may also display a graph showing the correlation between the flow rate calculated from the pressure inside the piping 12a based on Boyle's Law and Charles's Law, and the flow rate of the gas flowing in from the gas inflow mechanism 33. The display unit 39 may also show the particle count or the change in the particle count over time. The display unit 39 may also show whether or not there is a particle count.

[0039] [Second Embodiment] A particle measurement system according to a second embodiment of the present disclosure will be described with reference to Figure 5. Figure 5 is a diagram showing an example of a particle measurement system according to the second embodiment.

[0040] The particle measurement system 100A includes a particle measurement device 30A. The particle measurement device 30A includes a light source 31 and a light receiving element 32. The particle measurement device 30A differs from the particle measurement device 30 shown in Figure 1 in that it does not have a gas inflow mechanism 33 and a monitor control unit 34. The other components of the particle measurement system 100A are the same as those of the particle measurement system 100, so their description is omitted.

[0041] The gas inflow mechanism 33 is disposed outside the particle measurement device 30A and is connected to the pipe 12b downstream of the irradiation region 12c (see FIG. 2).

[0042] In the second embodiment, the control unit 20 has a function as a monitor control unit 34. In other words, the control unit 20 includes a measurement unit, a flow rate control unit, a measurement unit, a storage unit, and a display unit. The control unit 20 communicates with the particle measurement device 30A. As a result, the light receiving element 32 photoelectrically converts the detected scattered light and transmits an electrical signal to the control unit 20.

[0043] The measurement unit of the control unit 20 measures the particle count using an electrical signal indicating the detection result of the scattered light received from the particle measurement device 30A. For example, the measurement unit measures the particle count based on the detection result of the scattered light. Further, the flow rate control unit of the control unit 20 controls the gas inflow mechanism 33 so that the pressure in the pipe 12b downstream of the irradiation region is lower than that in the pipe 12a upstream of the irradiation region, and a gas having a flow rate that adjusts the fluid velocity passing through the irradiation region flows into the downstream pipe 12b.

[0044] As a result, the particle measurement system 100A can improve the measurement sensitivity and detection rate of the particles floating in the fluid passing through the pipe 12 by the particle measurement device 30A and the control unit 20 cooperating to adjust the fluid velocity passing through the irradiation region 12c.

[0045] In the first embodiment, in the particle measurement system 100, the particle measurement device 30 has a function of a device (computer) that executes a particle measurement method to be described later. At this time, the control unit that controls the particle measurement method is the monitor control unit 34 included in the particle measurement device 30.

[0046] In the second embodiment, in the particle measurement system 100A, the particle measurement device 30A and the control unit 20 cooperate to execute the particle measurement method. At this time, the control unit that controls the particle measurement method is the control unit 20.

[0047] However, the implementation means of the control unit that controls the particle measurement method is not limited to these. The particle measurement devices 30 and 30A may have some functions of the monitor control unit 34, and the remaining functions may be possessed by other devices such as the control unit 20 or a server device (such as a cloud server). In this case, communication is performed between the particle measurement devices 30 and 30A having some functions of the control unit and the control unit 20 or the server device having the remaining functions, and the processing of the particle measurement method is executed in cooperation.

[0048] [Particle Measurement Method] Next, a particle measurement method according to an embodiment will be described with reference to FIG. 6. FIG. 6 is a flowchart showing an example of a particle measurement method according to an embodiment. The control unit that controls the particle measurement method is, for example, the monitor control unit 34, the control unit 20, or the like. Here, the monitor control unit 34 controls the particle measurement method.

[0049] (Irradiation Step: ST1) In step ST1, the measurement unit 35 controls the light source 31 to irradiate light toward the fluid flowing in the pipe 12 under reduced pressure connected to the processing device 10. The measurement unit 35 may control the light source 31 to irradiate light after the pressure measured by the pressure gauge 13 has stabilized.

[0050] (Gas Inflow Step: ST2) Next, in step ST2, the flow rate control unit 36 causes a gas having a flow rate that adjusts the fluid velocity passing through the irradiation region 12c to flow into the pipe 12b, where the pressure in the pipe 12b downstream of the irradiation region 12c is lower than that in the pipe 12a upstream of the irradiation region 12c. The flow rate control unit 36 controls the gas inflow mechanism 33 to cause a gas such as air with a predetermined flow rate to flow into the downstream pipe 12b.

[0051] (Scattered Light Detection Step: ST3) Next, in step ST3, the measurement unit 35 acquires, from the light receiving element 32, the detection result of scattered light scattered by particles floating in the fluid passing through the light irradiation region 12c in the pipe 12.

[0052] (Measurement process: ST4) Next, in step ST4, the measurement unit 35 measures the particle count based on the detection result of scattered light d. The measurement unit 35 stores the measured particle count in a storage area such as the storage unit 38.

[0053] (Count determination process: ST5) Next, in step ST5, the flow velocity control unit 36 ​​determines whether the particle count exceeds a preset threshold. If the flow velocity control unit 36 ​​determines that the particle count does not exceed the preset threshold, it returns to step ST2 and controls the flow rate of the gas introduced into the pipe 12b again. For example, the flow velocity control unit 36 ​​increases the flow rate of the gas introduced into the pipe 12b and controls it to further lengthen the time that particles stay in the irradiation area 12c. The flow velocity control unit 36 ​​repeats the process from steps ST2 to ST5 until it determines in step ST5 that the particle count exceeds a preset threshold. If the flow velocity control unit 36 ​​determines that the particle count exceeds a preset threshold, it proceeds to step ST6.

[0054] (Contamination Determination Process: ST6) Next, in step ST6, the measurement unit 35 determines the contamination status inside the processing device 10 based on the relative changes in multiple particle counts stored in the storage unit 38. For example, the measurement unit 35 may determine that the processing device 10 is contaminated when the difference in multiple particle counts measured continuously over time is greater than a preset difference. If the measurement unit 35 determines that the processing device 10 is not contaminated, it returns to step ST3 and continues the processing from step ST3 onward.

[0055] (Display process: ST7) If the measurement unit 35 determines in step ST6 that the inside of the processing device 10 is contaminated, in step ST7 the display unit 39 displays a message prompting cleaning of the processing device 10, then returns to step ST3 and continues the process from step ST3 onward.

[0056] Note that the processing order of steps ST1 and ST2 is not limited to this; step ST2 may be executed before step ST1. Also, the processing of steps ST6 and ST7 can be omitted. In this case, after executing step ST5, return to step ST2 or ST3 and continue processing from step ST2 or ST3 onward.

[0057] The particle measurement systems 100 and 100A can improve the measurement sensitivity and detection rate of particles suspended in the fluid passing through the pipe 12 by adjusting the fluid velocity passing through the pipe 12 through the particle measurement method described above.

[0058] It should be noted that the embodiments disclosed herein are illustrative and not restrictive in all respects. Indeed, the embodiments described above can be embodied in a variety of forms. Furthermore, the embodiments described above may be omitted, replaced, or modified in various ways without departing from the scope and spirit of the attached claims.

[0059] Furthermore, the following additional information is disclosed with respect to the above embodiments. <Additional Information> (1) A particle measuring device comprising: a light source configured to irradiate light toward a fluid flowing through a pipe under reduced pressure connected to a processing device; a detection unit configured to detect scattered light scattered by particles suspended in the fluid passing through the irradiated area of ​​the light in the pipe; a measurement unit configured to measure the particle count based on the detection result of the scattered light; and a flow velocity control unit configured to allow a gas flow rate to flow into the downstream pipe, where the pressure in the pipe downstream of the irradiated area is lower than the pressure in the pipe upstream of the irradiated area, thereby adjusting the velocity of the fluid passing through the irradiated area. (2) The particle measuring device according to (1), further comprising a gas inflow mechanism connected to the downstream pipe and configured to allow a gas flow rate to flow into the downstream pipe. (3) The particle measuring device according to (1) or (2), wherein the light source irradiates light in a direction transverse to the pipe. (4) The particle measuring device according to any one of (1) to (3), wherein the light is laser light. (5) The particle measuring device according to (4), wherein the detection unit is located outside the irradiation area in the pipe irradiated with the laser light, and is located at a position capable of receiving the scattered light. (6) The particle measuring device according to any one of (1) to (5), comprising a measuring unit configured to measure the pressure in the upstream pipe or the velocity of the fluid, wherein the flow velocity control unit controls the flow rate of the gas to be introduced into the downstream pipe based on the pressure or the velocity of the fluid. (7) The particle measuring device according to any one of (1) to (6), wherein the flow velocity control unit controls the flow rate of the gas to be introduced into the downstream pipe so that the particle count exceeds a preset threshold. (8) The particle measuring device according to any one of (1) to (7), wherein the measuring unit measures the count of a plurality of particles over time under the same measurement conditions and determines the contamination status inside the processing device based on the relative change in the count of the plurality of particles.(9) The particle measuring device according to (8), further comprising a display unit that displays the particle count or the result of determining the contamination status in the processing device. (10) A particle measuring system comprising: a light source configured to irradiate light toward a fluid flowing through a pipe under reduced pressure connected to the processing device; a detection unit configured to detect scattered light scattered by particles suspended in the fluid passing through the light irradiation area in the pipe; a measurement unit configured to measure the particle count based on the detection result of the scattered light; a flow velocity control unit configured to allow a flow rate of gas to flow into the downstream pipe, where the pressure in the pipe downstream of the irradiation area is lower than the pressure in the pipe upstream of the irradiation area; and a gas inlet mechanism connected to the downstream pipe and configured to introduce the gas of the flow rate into the downstream pipe. (11) A particle measurement method comprising: irradiating light onto a fluid flowing through a pipe under reduced pressure connected to a processing device; detecting scattered light scattered by particles suspended in the fluid passing through the light-irradiated area in the pipe; measuring the particle count based on the detection result of the scattered light; and introducing a gas flow rate into the downstream pipe at a rate that adjusts the velocity of the fluid passing through the irradiation area, such that the pressure in the pipe downstream of the irradiation area is lower than the pressure in the pipe upstream of the irradiation area.

[0060] 10: Processing unit 11: Exhaust system 12: Piping 12c: Irradiation area 20: Control unit 30: Particle measuring device 31: Light source 32: Light receiving element 33: Gas inflow mechanism 34: Monitor control unit 35: Measurement unit 36: Flow velocity control unit 37: Measurement unit 38: Memory unit 39: Display unit 100, 100A: Particle measuring system

Claims

1. A particle measuring device comprising: a light source configured to irradiate light toward a fluid flowing through a pipe under reduced pressure connected to a processing device; a detection unit configured to detect scattered light scattered by particles suspended in the fluid passing through the irradiated area of ​​the light within the pipe; a measurement unit configured to measure the particle count based on the detection result of the scattered light; and a flow velocity control unit configured to introduce a gas at a flow rate that adjusts the velocity of the fluid passing through the irradiated area into the downstream pipe, where the pressure in the pipe downstream of the irradiated area is lower than the pressure in the pipe upstream of the irradiated area.

2. The particle measuring device according to claim 1, further comprising a gas inflow mechanism connected to the downstream piping and configured to allow gas of the specified flow rate to flow into the downstream piping.

3. The particle measuring apparatus according to claim 1 or claim 2, wherein the light source irradiates the light in a direction that crosses the pipe.

4. The particle measuring apparatus according to claim 1 or claim 2, wherein the light is laser light.

5. The particle measuring device according to claim 4, wherein the detection unit is positioned outside the irradiation area within the pipe irradiated with the laser light, and is positioned to receive the scattered light.

6. The particle measuring device according to claim 1 or 2, further comprising a measuring unit configured to measure the pressure in the upstream piping or the velocity of the fluid, wherein the flow velocity control unit controls the flow rate of the gas to be introduced into the downstream piping based on the pressure or the velocity of the fluid.

7. The particle measuring device according to claim 1 or 2, wherein the flow velocity control unit controls the flow rate of the gas introduced into the downstream piping so that the particle count exceeds a preset threshold.

8. The particle measuring device according to claim 1 or 2, wherein the measuring unit measures the count of a plurality of particles over time under the same measurement conditions, and determines the contamination status within the processing device based on the relative change in the count of the plurality of particles.

9. The particle measuring device according to claim 8, further comprising a display unit that displays the count of the particles or the result of determining the contamination status within the processing device.

10. A particle measurement system comprising: a light source configured to irradiate light toward a fluid flowing through a piping under reduced pressure connected to a processing device; a detection unit configured to detect scattered light scattered by particles suspended in the fluid passing through the irradiated area of ​​the light within the piping; a measurement unit configured to measure the particle count based on the detection result of the scattered light; a flow velocity control unit configured to introduce a gas flow rate into the downstream piping, where the pressure in the piping downstream of the irradiated area is lower than that in the piping upstream of the irradiated area; and a gas inlet mechanism connected to the downstream piping and configured to introduce the gas flow rate into the downstream piping.

11. A particle measurement method comprising: irradiating light onto a fluid flowing through a piping under reduced pressure connected to a processing device; detecting scattered light scattered by particles suspended in the fluid passing through the light-irradiated area within the piping; measuring the particle count based on the detection result of the scattered light; and introducing a gas at a flow rate that adjusts the velocity of the fluid passing through the irradiation area into the downstream piping, where the pressure in the piping downstream of the irradiation area is lower than that in the piping upstream of the irradiation area.

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