JP5112032B2 - Fluorine gas measuring method and apparatus - Google Patents

Description

  The present invention relates to a fluorine gas measuring method and apparatus, and more particularly to a fluorine gas measuring method and apparatus for measuring the concentration of fluorine gas contained in exhaust gas from a plasma CVD apparatus or a detoxifying apparatus.

  As a fluorine gas concentration meter that can measure the concentration of fluorine gas contained in various gases in real time, a fluorine gas concentration meter using a selective luminescence reaction between a specific substance, for example, an organic substance and fluorine gas, is commercially available. ing. This fluorine gas concentration meter detects the fluorine gas concentration by amplifying the intensity of the generated light with a photomultiplier tube or the like because the luminescence reaction depends on the concentration of fluorine gas contained in the gas. It is considered promising as an analyzer that can measure fluorine gas itself with high sensitivity (for example, see Non-Patent Document 1).

In addition, when measuring the concentration of fluorine gas using the fluorine gas concentration meter as described above, the sample gas is used to improve the stability of the fluorine gas concentration meter and to respond quickly to changes in the fluorine gas concentration. Immediately before measuring the fluorine gas concentration in the sample, it is also proposed to perform pretreatment of the measurement part (fluorination and calibration of the part in contact with the sample gas) using standard fluorine gas or xenon fluoride (for example, (See Patent Document 1).
Sanyo Trading Co., Ltd., Scientific Instruments Division, Product Information by Manufacturer, URS Corporation, Fluorine Gas Concentration Meter. [Search December 6, 2007], Internet <URL: http: //www.sanyo-si.com/product/u_urs_001.html> JP 2007-107904 A

  However, when the fluorine gas concentration meter was used, the emission intensity was continuously measured by switching from nitrogen gas (A) containing no fluorine gas to nitrogen gas (B) containing 200 ppm of fluorine gas. The results as shown in Fig. 1 were obtained. That is, immediately after switching from nitrogen gas (A) containing no fluorine gas to nitrogen gas (B) containing fluorine gas, the emission intensity jumps up instantaneously and then gradually decreases. Immediately after gas switching, the flow rate to the fluorine gas concentration meter also fluctuates, and it takes a few seconds for the flow rate to stabilize, but thereafter the flow rate is stable and the fluorine gas concentration in the gas is also constant. It should be. In order to measure the accurate and real-time fluorine gas concentration, it is desirable that the emission intensity be instantaneously constant, but the actual emission intensity does not become constant even after 6 hours have passed since gas switching. It remained a decreasing trend.

  Moreover, when the calibration curve data of the same fluorine gas concentration meter were acquired over about one month, the result shown in FIG. 8 was obtained. The data in FIG. 8 uses nitrogen gas containing 200 ppm of fluorine gas as the maximum concentration, but the emission intensity at the same concentration decreases day by day, and decreases to about 1 / 2.5 in about one month. I have. From this, it can be said that when this fluorine gas concentration meter is used, it is necessary to frequently calibrate in order to obtain an accurate fluorine gas concentration. Furthermore, since the calibration curve in FIG. 8 is non-linear in the low concentration region, a gas containing a plurality of concentrations of fluorine gas is introduced into the fluorine gas concentration meter when creating a calibration curve. It can be said that calibration is necessary.

  As a method of suppressing fluctuations in the fluorine concentration in the gas when flowing a constant concentration of fluorine gas through the metal pipe, a high flow rate of fluorine gas without changing the concentration, a constant flow rate, pressure and Fluorine passivation treatment of the inner surface of a metal pipe by flowing for a certain time at temperature is known. This method is effective in a system where the material in contact with the fluorine gas is simple. However, in order to guide organic substances that cause a selective emission reaction with the fluorine gas in the portion in contact with the fluorine gas and the emitted light to the photomultiplier tube. In the case of including a window material such as sapphire glass, flowing a high concentration of fluorine gas for a long time may cause a decrease in emission intensity due to abrupt deterioration of the organic matter or a decrease in analytical sensitivity due to deterioration of the window material (of the generated light The fluorination treatment is not an effective treatment method for the fluorine gas concentration meter as described above.

  In addition, as described in Patent Document 1, in the case where the pretreatment of the measurement unit is performed using the standard fluorine gas immediately before measuring the fluorine gas concentration in the sample gas, the standard fluorine gas is brought into the measurement site. However, since standard fluorine gas is a toxic high-pressure gas, it is effective in an environment where transportation means and facilities to be used are in place, but if the environment is not in place, transportation and gas line There is a problem that maintenance takes time and cost. In addition, it has been proposed to use a small amount of xenon fluoride instead of standard fluorine gas for pretreatment of the measurement section, but xenon fluoride (xenon difluoride) is also a hazardous substance, so standard fluorine Although it is not as much as gas, it still requires effort and cost to improve the transportation and usage environment. In addition, it takes at least about 3 hours for the pretreatment of the measurement unit, and taking into account that this pretreatment must be performed every time immediately before measuring the sample gas, a very large amount of pretreatment is required. There was also a problem of having to spend time.

  Therefore, the present invention improves the stability of the optical fluorine gas concentration meter as described above, and can quickly and accurately respond to changes in the fluorine gas concentration, and can measure standard fluorine gas and xenon fluoride. It is an object of the present invention to provide a fluorine gas measuring method and apparatus capable of easily and reliably pre-treating a measuring unit without bringing it into the field.

  In order to achieve the above object, a fluorine gas measuring method of the present invention is a fluorine gas measuring method for measuring a fluorine gas concentration in a sample gas using a light emission type fluorine gas concentration meter. Is continuously introduced, and the sample gas is intermittently introduced into the inert gas to measure the fluorine gas concentration in the sample gas.

  Furthermore, the fluorine gas measuring method of the present invention is characterized in that the calibration of the fluorine gas concentration meter is performed by intermittently introducing a calibration gas into the fluorine gas concentration meter, and the fluorine gas concentration in the sample gas is measured. The calibration gas or the sample gas is intermittently introduced into the fluorine gas concentration meter, and the calibration gas is a gas containing fluorine gas or xenon fluoride gas. .

  The fluorine gas measuring device of the present invention is a fluorine gas measuring device that measures the fluorine gas concentration in a sample gas using a light emission type fluorine gas concentration meter, wherein an inert gas is continuously supplied to the light emission type fluorine gas concentration meter. A sample gas intermittent injection means for intermittently injecting the sample gas into the inert gas is provided in the inert gas introduction path to be introduced into the inert gas.

  Further, in the fluorine gas measuring apparatus of the present invention, the sample gas intermittent injection means is a combination of a six-way switching valve and a gas metering pipe provided in the inert gas introduction path, and the hexagonal switching valve includes the fluorine gas measuring device. A concentration meter inlet path connected to the gas concentration meter, a sample gas introduction path connected to the sample gas source, an inert gas introduction path connected to the inert gas supply unit, and a gas connected to the inlet of the gas metering tube A metering pipe inlet path, a gas metering pipe outlet path connected to the outlet of the gas metering pipe, and a sample gas discharge path connected to the flow rate adjusting means are connected to each other as a valve switching position from the inert gas supply unit. The inert gas is introduced from the inert gas introduction path and led out to the concentration meter inlet path, and the sample gas from the sample gas source is introduced from the sample gas introduction path to the gas meter. A metering position led to the sample gas discharge path through a pipe inlet path, the gas metering pipe, and the gas metering pipe outlet path, and the inert gas introduced from the inert gas introduction path to the gas metering pipe inlet Measurement position where the sample gas is introduced into the concentration meter inlet path through the path, the gas metering pipe, and the gas metering pipe outlet path, and the sample gas is introduced from the sample gas introduction path and led out to the sample gas discharge path Or a combination of a gas injection port provided in the inert gas introduction path and a gas tight syringe for injecting the sample gas from the gas injection port. It is characterized by being.

  According to the present invention, the sample gas in an amount corresponding to the fluorine concentration is intermittently introduced into the fluorine gas concentration meter with the inert gas, so that the light emitting portion and the sample gas in the measurement portion of the fluorine gas concentration meter are The contact time is extremely short, and the light-emitting reaction site can be suppressed to only a very thin pole surface, so that a decrease in light emission intensity can be suppressed extremely efficiently. Furthermore, by-products generated by the luminescence reaction can be easily removed, so that a small amount of inert gas can be introduced into the measurement section for a short time, and the luminescent surface can be quickly brought into the initial state (the state before flowing a gas containing fluorine gas). ) Can be restored. For this reason, the emission intensity is not slowed down for a long time, and the fluorine gas concentration in the sample gas is accurately reproducible, as seen when the sample gas is continuously introduced into the measurement unit. It becomes possible to measure well. In addition, since the emission intensity is gradual and does not decrease for a long time, it is not necessary to perform fluorination treatment for a long time, and calibration data is acquired during calibration using fluorine standard gas or xenon difluoride. Therefore, the fluorine standard gas or xenon fluoride is introduced into the fluorine gas concentration meter through the same route as the sample gas under the same conditions. Yes.

  In this case, although it is necessary to calibrate the fluorine gas concentration meter in advance using a fluorine standard gas or xenon fluoride, these need not be performed immediately before the sample gas measurement, and may be performed in advance. Therefore, there is no need to bring fluorine standard gas or xenon fluoride into the sample gas measurement site. For this reason, it is not necessary to spend time and money on the maintenance of these transportation means and facilities, and the fluorine gas concentration in the sample gas can be accurately measured at a very low cost. In addition, since fluorine standard gas and xenon fluoride, which are harmful substances, are not brought into the measurement site, on-site analysis of fluorine gas can be performed extremely safely.

  In addition, the fluorine gas measuring device of the present invention does not need to incorporate means for supplying standard fluorine gas or xenon fluoride, or means for switching between these and the sample gas, so the measuring device can be made extremely compact. It becomes possible to summarize.

  FIG. 1 is a system diagram of a fluorine gas measuring apparatus showing an embodiment of the present invention. This fluorine gas measuring device includes a light emission type fluorine gas concentration meter 11 that measures a fluorine gas concentration in a sample gas by a light emission reaction, a sample gas source 12 such as exhaust gas from a plasma CVD device or an abatement device at a measurement site, and the like. An inert gas supply unit 13 for supplying an inert gas, a six-way switching valve 14 for switching a gas to be introduced into the fluorine gas concentration meter 11, a gas metering tube 15 for measuring a certain amount of sample gas, A flow rate adjusting means 16 for adjusting the flow rate of the sample gas and each path connecting them are provided.

  The six-way switching valve 14 and the gas metering tube 15 function as sample gas intermittent injection means for intermittently injecting a predetermined amount of sample gas into the inert gas continuously introduced into the fluorine gas concentration meter 11. The six ports of the six-way switching valve 14 have a concentration meter inlet path 21 connected to the fluorine gas concentration meter 11, a sample gas introduction path 22 connected to the sample gas source 12, and the inert gas supply. An inert gas introduction path 23 connected to the section 13, a gas metering pipe inlet path 24 connected to the inlet of the gas metering pipe 15, a gas metering pipe outlet path 25 connected to the outlet of the gas metering pipe 15, A sample gas discharge path 26 connected to the flow rate adjusting means 16 is connected to each port, and the position of each port is a measuring position at which the sample gas is measured by the gas measuring tube 15 (the internal channel is the position of the solid line in FIG. 1). )When, Charge measurement position for measuring the concentration of fluorine gas in the gas in the fluorine gas concentration meter 11 (internal flow path is broken line position in FIG. 1) is formed to be switchable to the.

  The gas metering tube 15 only needs to be able to meter a certain amount of sample gas including the front and rear paths 24 and 25, and a tube having an appropriate internal volume according to the fluorine gas concentration in the sample gas is used. Can do. For example, a tube having an internal volume of about several tens ml when the concentration of fluorine gas in the sample gas is low and about several tens to several hundreds of μl when the concentration is high may be selected.

  The inert gas supply unit 13 does not contain a fluorine gas and does not contain a component that adversely affects the measurement of the fluorine gas by the fluorine gas concentration meter 11, such as high-purity nitrogen gas or argon gas. Can be used, and those filled with an inert gas can be used, or an inert gas used in another facility can be drawn in and used. The supply pressure of the inert gas in the inert gas supply unit 13 is desirably 0.3 MPaG or more.

  The inert gas introduction path 23 is provided with a pressure adjusting means 17 for adjusting the pressure of the inert gas to be introduced and a flow rate adjusting means 18 for adjusting the flow rate, depending on the state of the sample gas and the like. It is formed so that an inert gas can be introduced at an optimum pressure and flow rate. A general pressure regulator corresponding to the pressure on the primary side and the secondary side can be used for the pressure adjustment means 17, and the flow rate adjustment means 18 can also be used according to the pressure, the flow rate adjustment range, and the flow rate adjustment accuracy. A commonly used mass flow controller can be used.

  The flow rate of the sample gas to be measured is adjusted by the flow rate adjusting means 16, but when the pressure of the sample gas in the sample gas source 12 is near atmospheric pressure, a diaphragm pump or the like is disposed in the sample gas discharge path 26. The sample gas may be sucked and introduced into the gas metering tube 15.

  Next, an example of a procedure for measuring the fluorine gas concentration in the sample gas using this fluorine gas measuring device will be described. First, before measuring the fluorine gas concentration in the sample gas, calibration of the fluorine gas concentration meter 11 in the fluorine gas measuring device and fluorination treatment of the portion in contact with the fluorine gas are performed. However, this operation may be performed in advance, and need not be performed immediately before measuring the sample gas.

  Since the calibration of the fluorine gas concentration meter 11 requires multipoint calibration, it is performed by introducing a fluorine-containing gas having a plurality of fluorine concentrations into the fluorine gas concentration meter 11. This fluorine-containing gas can be prepared by preparing a plurality of fluorine standard gases with different fluorine concentrations, but by diluting one fluorine standard gas with an inert gas not containing fluorine, A plurality of gases may be generated and used.

  The calibration of the fluorine gas concentration meter 11 and the fluorination treatment of the portion in contact with the fluorine gas of the fluorine gas measuring device are performed by introducing the fluorine-containing gas from the sample gas introduction path 22. First, the flow path of the six-way switching valve 14 is switched to the measurement position indicated by the solid line in FIG. 1, and the fluorine-containing gas introduced from the sample gas introduction path 22 is changed to the flow path A1, gas measurement of the six-way switching valve 14. The pipe inlet path 24, the gas metering pipe 15, the gas metering pipe outlet path 25, the flow path A2 of the hexagonal switching valve 14, the sample gas discharge path 26, and the flow rate adjusting means 16 are flowed in this order, and the flow rate adjusting means 16 adjusts the flow rate. The inert gas introduced from the inert gas source 13, such as high purity nitrogen gas, is introduced with the pressure adjusted by the pressure adjusting means 17 and the flow rate adjusted by the flow rate adjusting means 18. The passage 23, the flow path A3 of the six-way switching valve 14, the concentration meter inlet passage 21, and the fluorine gas concentration meter 11 are flowed in this order.

  The pressure and flow rate of the fluorine-containing gas and the inert gas can be arbitrarily set according to the configuration of the fluorine gas measuring device, particularly the configuration of the fluorine gas concentration meter 11, but usually the flow rate of the fluorine-containing gas is 1L. The inert gas may be adjusted to a pressure of 0.1 to 0.3 MPa (gauge pressure, the same shall apply hereinafter) and a flow rate of 200 to 500 ml / min.

  In this state, the gas metering tube 15 is held for a predetermined time, for example, about 1 to several minutes, and after the gas metering tube 15 is filled with the fluorine-containing gas, the six-way switching valve 14 is switched to the measurement position indicated by the broken line in FIG. . Thereby, the fluorine-containing gas introduced from the sample gas introduction path 22 flows in the order of the sample gas discharge path 26 and the flow rate adjusting means 16 from the flow path B1 of the six-way switching valve 14, and the inert gas is introduced into the inert gas. Path 23, flow path B2 of the hexagonal switching valve 14, gas metering pipe inlet path 24, gas metering pipe 15, gas metering pipe outlet path 25, flow path B3 of the hexagonal switching valve 14, densitometer inlet path 21, fluorine gas concentration meter It flows in order of 11.

  A predetermined amount of fluorine-containing gas measured by the gas metering pipe 15 is pushed out to the gas metering pipe outlet path 25 by the inert gas flowing in from the gas metering pipe inlet path 24, and is accompanied by the inert gas to be a six-way switching valve. 14 is introduced into the fluorine gas concentration meter 11 from the channel B3 through the concentration meter inlet passage 21, and the fluorine gas concentration in the fluorine-containing gas is measured by the fluorine gas concentration meter 11, and the emission intensity data according to the fluorine gas concentration is measured. Is obtained.

  Thereafter, the hexagonal switching valve 14 is switched to the metering position, and the metering of the fluorine-containing gas by the gas metering tube 15 is resumed. The time for switching the hexagonal switching valve 14 from the measurement position to the measurement position varies depending on the length of the concentration meter inlet path 21, but is usually several seconds to several tens of seconds. Until the stable emission intensity data is obtained, the hexagonal switching valve 14 is switched between the measurement position and the measurement position, and the fluorine gas concentration meter 11 intermittently performs a plurality of operations for measuring the fluorine gas concentration in the fluorine-containing gas. Repeat for example 3 times or more. The same operation is performed a plurality of times for each of three or more kinds of fluorine-containing gases having different fluorine gas concentrations, data necessary for creating a calibration curve is acquired, and a calibration curve is created.

  Since the calibration curve is thus created, the fluorine gas concentration meter 11 and the gas contact portion in each path are sufficiently in contact with the fluorine-containing gas having various concentrations introduced in the calibration operation. The portion is fluorinated with fluorine, and the fluorine passivation treatment is completed. That is, by performing calibration work of the fluorine gas concentration meter 11 in advance in a place where the environment is maintained, a fluorine passivation process is performed for a long time using a fluorine standard gas or a xenon fluoride gas at the measurement site. This eliminates the need to bring standard fluorine gas or xenon fluoride gas into the measurement site, making it possible to easily and quickly measure the fluorine gas concentration in various locations without considering transportation and usage environments. it can.

  The measurement of the fluorine gas concentration in the sample gas at the measurement site is performed by first connecting the sample gas introduction path 22 to a path such as exhaust gas discharged from a plasma CVD apparatus or a detoxification apparatus serving as the sample gas source 12, and The sample gas introduction path 22 can be introduced. Further, the inert gas introduction path 23 is connected to a gas container serving as the inert gas supply unit 13 or appropriate piping at the measurement site so that the inert gas can be introduced into the inert gas introduction path 23. Note that the type of the inert gas may be the same as the inert gas used in the calibration operation, or may be a different gas as long as the above conditions are satisfied.

  The hexagonal switching valve 14 is switched to the metering position, and the inert gas supplied from the inert gas source 13 is supplied to the inert gas introduction path 23 and the hexagonal switching valve 14 via the pressure adjusting means 17 and the flow rate adjusting means 18. The flow was made in the order of the flow path A3, the concentration meter inlet passage 21, and the fluorine gas concentration meter 11, and the pressure and flow rate of the inert gas were set by the pressure adjusting means 17 and the flow rate adjusting means 18 in the calibration operation. Adjust to the same pressure and flow rate as the pressure and flow rate. In addition, the sample gas from the sample gas source 12 is supplied to the flow path A1, the gas metering pipe inlet path 24, the gas metering pipe 15, the gas metering pipe outlet path 25, the flow path A2 of the hexagonal switch valve 14, the sample. The gas is discharged in the order of the gas discharge path 26 and the flow rate adjusting unit 16, and the flow rate adjusting unit 16 adjusts the flow rate of the sample gas to about 1 L / min.

  After the hexagonal switching valve 14 has held the state of the metering position for 1 to several minutes, the hexagonal switching valve 14 is switched to the measurement position, and the sample gas metered in the gas metering tube 15 is accompanied by an inert gas and fluorine. The gas is introduced into the gas concentration meter 11 and the fluorine gas concentration meter 11 measures the fluorine gas concentration in the sample gas. After the time for the sample gas to reach the measuring part of the fluorine gas concentration meter 11 has elapsed, the six-way switching valve 14 is switched to the measuring position and the measurement of the sample gas is resumed. The time for switching the hexagonal switching valve 14 from the measurement position to the measurement position may be about several seconds to several tens of seconds as in the calibration operation. After measuring the sample gas for a predetermined time, the hexagonal switching valve 14 is switched again from the measuring position to the measuring position, and the fluorine gas concentration meter 11 measures the fluorine gas concentration in the sample gas.

  Hereinafter, the sample gas measured by the gas metering tube 15 is intermittently introduced into the fluorine gas concentration meter 11 by switching the hexagonal switching valve 14 between the measurement position and the measurement position at a predetermined interval, and the fluorine gas concentration in the sample gas Is repeated a plurality of times, preferably three times or more. The time interval of the fluorine gas concentration measurement that is repeated intermittently varies depending on the amount of the sample gas measured by the gas metering tube 15 and the fluorine gas concentration in the sample gas, but it is desirable that the interval be at least 1 minute.

  In addition, the same operation as the measurement of the sample gas is repeated a plurality of times, for example, three times or more, and after the pretreatment of the portion in contact with the sample gas is performed using the sample gas, the fluorine gas concentration in the sample gas is actually measured. By starting this operation, the fluorine gas concentration in the sample gas can be measured more accurately.

  FIG. 2 is a system diagram showing another embodiment of the fluorine gas measuring device of the present invention. In this embodiment, a gas inlet 32 provided on the downstream side of the pressure adjusting means 17 and the flow rate adjusting means 18 in the inert gas introduction path 31 including the pressure adjusting means 17 and the flow rate adjusting means 18, and the gas inlet 32. The sample gas intermittent injection means is constituted by a combination with the gas tight syringe 33 for injecting the sample gas from the above.

  The sample gas and the fluorine-containing gas for calibration, which are measured in a predetermined amount in the gas tight syringe 33, are supplied from the inert gas supply unit 13, and the pressure and flow rate are adjusted by the pressure adjusting unit 17 and the flow rate adjusting unit 18. The gas is injected into the inert gas flowing through the inert gas introduction path 31 from the gas tight syringe 33 through the gas inlet 32 and introduced into the fluorine gas concentration meter 11 connected downstream. Therefore, the sample gas and fluorine-containing gas are intermittently introduced into the fluorine gas concentration meter 11 by repeating the operation of injecting the sample gas and fluorine-containing gas from the gas tight syringe 33 through the gas inlet 32 at appropriate time intervals. can do. In addition, a well-known thing can be used for the gas inlet 32 and the gas tight syringe 33. FIG.

  As described above, the sample gas intermittent injection means includes a combination of the six-way switching valve 14 provided in the inert gas introduction path 23 and the gas metering pipe 15, a gas inlet 32 provided in the inert gas introduction path 31, and a gas. Various configurations such as a combination with the tight syringe 33 can be employed.

  An experiment was performed using the fluorine gas measuring apparatus having the configuration shown in FIG. High purity nitrogen gas was used as the inert gas, the pressure was adjusted to 0.2 MPa, and the flow rate was adjusted to 200 ml / min. The flow rates of the sample gas and the calibration fluorine standard gas were adjusted to 1 L / min. The internal volume of the gas metering tube was 10 ml.

  First, calibration of the fluorine gas concentration meter was performed, and a calibration curve was created using four types of fluorine-containing gases having different fluorine gas concentrations. The same calibration work was performed in the same way at a later date to confirm the reproducibility of the calibration curve. The result is shown in FIG.

  When the time course of the measurement line shown in FIG. 3 is compared at 100 ppm of the same concentration as the data shown in FIG. 8, the conventional case shown in FIG. 8 decreases to about 60% in 5-10 days. On the other hand, in the case of the present embodiment shown in FIG. 3, it decreases only about 10% in 5 to 7 days. From this, it can be seen that the reproducibility of the calibration curve has been greatly improved, and if there is no problem with the measurement accuracy of the fluorine gas concentration in the sample gas within this accuracy range, the fluorine standard gas is intermittently used in advance. Perform calibration work to be introduced into the fluorine gas concentration meter in a laboratory equipped with facilities and create a calibration curve, so that calibration work can be performed immediately before measuring the fluorine gas concentration in the sample gas at the actual measurement site. You can see that you don't have to.

  Further, three days after preparing the calibration curve in the same manner as described above, five types of fluorine-containing gases with known fluorine gas concentrations of 47.6 ppm, 90.9 ppm, 9.9 ppm, and 24.4 ppm were used, As described above, the fluorine gas concentration of each fluorine-containing gas was measured by switching the six-way switching valve and intermittently introducing each fluorine-containing gas into the fluorine gas concentration meter. The result is shown in FIG.

  From the results shown in FIG. 4, in the data several times immediately after the start of the measurement, the fluorine gas concentration was displayed at a low level, but thereafter the fluorine gas was reproducible with high reproducibility according to the change in the fluorine gas concentration and high response. It can be seen that the gas concentration is displayed. Furthermore, it can be seen that accuracy and responsiveness can be improved by performing preliminary work to intermittently introduce the sample gas into the fluorine concentration meter before acquiring actual concentration data at the measurement site.

  Further, the day after the calibration curve is created in the same manner as described above, the fluorine gas measuring device is moved from the laboratory to the vicinity of the on-site combustion-type abatement device, and the fluorine gas concentration in the exhaust gas discharged from the combustion-type abatement device is measured. Measurements were taken at 5 minute intervals. The result is shown in FIG. From this result, the data of 3 points immediately after the start of measurement was displayed lower, but the fluorine gas concentration after that is stable at about 1.5 ppm, and the fluorine gas concentration can be measured in a stable state for a long time. It can be seen that it is.

A calibration curve was prepared in the same manner as in Example 1 without changing the other conditions except that the gas measuring tube was replaced with one having an internal volume of 0.05 ml. Two days later, the fluorine gas measuring device was moved close to the plasma CVD device, and the fluorine gas concentration in the exhaust gas discharged from the plasma CVD device was measured. FIG. 6 shows the result of measuring the fluorine gas concentration in the exhaust gas at the time of plasma cleaning using C ₂ F ₆ gas and oxygen gas at intervals of 1 minute. From this result, it can be seen that even if the fluorine gas concentration fluctuates, it is possible to perform measurement that sufficiently follows.

It is a systematic diagram of a fluorine gas measuring device showing an example of the present invention. It is a systematic diagram which shows the other example of a form of the fluorine gas measuring apparatus of this invention. FIG. 3 is a graph showing a change over time of a calibration curve in Example 1. It is a figure which shows the result of having measured the fluorine gas density | concentration in four types of fluorine-containing gas of known density | concentration. It is a figure which shows the result of having measured the fluorine gas density | concentration in the waste gas discharged | emitted from a combustion type abatement apparatus at intervals of 5 minutes. It is a figure which shows the result of having measured the fluorine gas density | concentration in the waste gas discharged | emitted from a plasma CVD apparatus at a 1-minute space | interval. It is a figure which shows a measurement result when using a fluorine gas concentration meter by the conventional method. It is a figure which shows the time-dependent change of a calibration curve when a fluorine gas concentration meter is used by the conventional method.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 11 ... Fluorine gas concentration meter, 12 ... Sample gas source, 13 ... Inert gas supply part, 14 ... Six-way selector valve, 15 ... Gas metering pipe, 16 ... Flow rate adjustment means, 17 ... Pressure adjustment means, 18 ... Flow rate adjustment means 21 ... Densitometer inlet path, 22 ... Sample gas introduction path, 23 ... Inert gas introduction path, 24 ... Gas metering pipe inlet path, 25 ... Gas metering pipe outlet path, 26 ... Sample gas discharge path, 31 ... Inert Gas introduction path, 32 ... gas inlet, 33 ... gas tight syringe

Claims (6)

  In a fluorine gas measurement method for measuring a fluorine gas concentration in a sample gas using a luminescent fluorine gas concentration meter, an inert gas is continuously introduced into the fluorine gas concentration meter, and the sample is introduced into the inert gas. A method for measuring fluorine gas, which comprises intermittently introducing gas and measuring the concentration of fluorine gas in the sample gas.   2. The fluorine gas measuring method according to claim 1, wherein the calibration of the fluorine gas concentration meter is performed by intermittently introducing a calibration gas into the fluorine gas concentration meter.   3. The fluorine gas measurement method according to claim 1, wherein the measurement of the fluorine gas concentration in the sample gas is performed after intermittently introducing a calibration gas or the sample gas into the fluorine gas concentration meter. .   4. The fluorine gas measuring method according to claim 2, wherein the calibration gas is a gas containing fluorine gas or xenon fluoride gas.   In the fluorine gas measuring apparatus for measuring the fluorine gas concentration in the sample gas using a light emission type fluorine gas concentration meter, the inert gas introduction path for continuously introducing the inert gas into the light emission type fluorine gas concentration meter, A fluorine gas measuring apparatus comprising a sample gas intermittent injection means for intermittently injecting a sample gas into the inert gas. The sample gas intermittent injection means is a combination of a six-way switching valve and a gas metering pipe provided in the inert gas introduction path, and a concentration meter inlet path connected to the fluorine gas concentration meter is connected to the six-way switching valve. A sample gas introduction path connected to the sample gas source, an inert gas introduction path connected to the inert gas supply unit, a gas metering pipe inlet path connected to the inlet of the gas metering pipe, and an outlet of the gas metering pipe A gas metering tube outlet path connected to the gas supply section and a sample gas discharge path connected to the flow rate adjusting means are connected to each other, and the inert gas from the inert gas supply section serves as the inert gas introduction path as a valve switching position. And the sample gas from the sample gas source is introduced from the sample gas introduction path to be introduced into the gas metering pipe inlet path, the gas metering pipe, and the gas. A metering position led out to the sample gas discharge path via a metering pipe outlet path, and the inert gas introduced from the inert gas introduction path to the gas metering pipe inlet path, the gas metering pipe, and the gas metering pipe A six-way switching valve formed so as to be switched to a measurement position that is led out to the concentration meter inlet path via the outlet path, and the sample gas is introduced from the sample gas introduction path and led to the sample gas discharge path. , or claim 5, wherein the from the gas inlet and the gas inlet provided in the inert gas introduction path combination with gas-tight syringe for injecting the sample gas, which is either Fluorine gas measuring device.

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