JPH09145616A - Method and device for air impurity monitor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To automatically and continuously measure the concentration of particles and impurities in atmosphere in a clean room almost regardless of the size of the particles and impurities, by providing a device which controls each line, a measurement device, an output device, and a record device in accordance with a specified order. SOLUTION: The pre-set quantity of ultrapure water is supplied into an impurity capturing vessel 1 capable of sealing through an ultrapure water introduction line 3a. Then, into the ultrapure water, specified quantity of atmosphere in a clean room is ventilated through an atmosphere ventilation line 4a, for generating sample water. At this time, the pressure in the vessel 1 is adjusted with an exhausting line 5a, so that supplying of the ultrapure water into the vessel 1 and ventilation of the atmosphere in the clean room into the ultrapure water are performed without stagnation. The generated sample water is, through a sample water introduction line 7a, introduced to a measurement device 9 measuring impurity concentration, and the measured result is outputted to an output device 11, and recorded in a recording device. The sample water which is not used for measurement is exhaust from a drain line 8a. A series of operation above is controlled with a control device 10.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an airborne impurity monitoring device for monitoring the impurity concentration in a clean room atmosphere used in electronic industries for manufacturing liquid crystal or semiconductor devices, nuclear power plants, pharmaceutical manufacturing plants, etc. A method for monitoring atmospheric impurities.

[0002]

2. Description of the Related Art Conventionally, in the liquid crystal and semiconductor integrated circuit device (LSI) industries, etc., it has been used in the manufacturing process in order to prevent pattern defects caused by fine particles and crystal defects caused by heavy metal contamination. Various measures have been taken such as controlling the concentration of impurities in the chemicals used and pure water used for cleaning, and preventing the generation of fine particles in a clean room, which is a manufacturing environment. However, in recent years, liquid crystals and L
With the progress of miniaturization of SI and the improvement of integration degree, the influence of contamination of silicon wafers, glass substrates, etc. by extremely small amounts of impurities existing in a clean room atmosphere becomes a big problem in the manufacturing process of these devices. Therefore, cleanliness higher than conventional is required.

Generally, impurities in a clean room atmosphere are in the form of gas, particles, mist, etc.,
When such impurities in the atmosphere of the manufacturing environment adhere to the liquid crystal glass substrate or the semiconductor substrate, the yield and reliability of the liquid crystal and semiconductor elements are reduced, so the impurities in the atmosphere of the manufacturing environment are controlled and maintained at extremely low concentrations. The need to manage is increasing.

For example, M having a gate length of about 0.25 μm
In the case of a ULSI integrated with an OS transistor, the gate oxide film is thinned to about 60 to 70 angstroms, and a minute increase in leak current, generation of defects in the gate oxide film, or deterioration in reliability is not limited to fine particles.
Depending on the impurity species, it is affected by the very small amount of impurities in the atmosphere of 1 ng / m ^{3 to} 1 μg / m ³ . It is also known that when using a chemically propagated photoresist, anions and ammonium ions in the atmosphere cause a decrease in dimensional accuracy, and such anions and ammonium ions are also caused by poor characteristics of liquid crystal and semiconductor elements. This causes a decrease in yield and reliability.

Conventionally, as a method for measuring the concentration of fine particles existing in a clean room, the atmosphere in the clean room is filtered by a filter, and the fine particles trapped on the filter are counted or measured by an electron microscope to measure the fine particle concentration. A method of measuring is used. Other,
A method is also used in which the particles contained in the atmosphere of the manufacturing environment are irradiated with a laser and the scattered light generated at that time is detected to measure the particle size and number of the suspended particles. A large number of measuring devices used for measuring such fine particle concentration are used as continuous monitoring instruments.

However, the particle size of fine particles detectable by these methods and measuring devices is currently 0.01.
The limit was about μm, and it was impossible to detect finer particles than this.

As impurities in the clean room,
As a method of measuring the concentration of water-soluble fine particles, metal ions, anions, organic substances, etc., for example, impurities are trapped in ultrapure water by an impinger method in which an atmosphere in a clean room is aerated with appropriate ultrapure water, and then obtained. The method of measuring the impurity concentration in the obtained solution by chemical analysis such as atomic absorption spectrophotometry or ion chromatography is used.

However, in the Impinger method and the method for measuring impurities by chemical analysis, it is necessary to maintain the accuracy and the reliability of the analysis value, and therefore a skilled person must perform the analysis work for about one day. There wasn't.

That is, when the clean room atmosphere is controlled by the above-mentioned conventional impurity concentration measuring apparatus and method at the manufacturing site of liquid crystal, semiconductor device, etc., it is found that an abnormality occurs in the clean room atmosphere. It will take about one day. Therefore, the substrate etc. are processed until the abnormality in the clean room atmosphere is detected, and even if it is later found that there is an abnormality in the analysis result, many products are already under abnormal environment. It had been processed.

Furthermore, since it takes a long time from when an abnormality occurs in a clean room atmosphere to when the abnormality is found, there are many cases where the cause of the abnormality has already been solved when the abnormality is found. It is extremely difficult to elucidate, and it is almost impossible to take measures to prevent the recurrence of abnormalities based on the same cause.

That is, according to the conventional method, not only is there a limit to the particle size of the fine particles that can be detected, but also the time required for the measurement to reflect the monitoring results in the atmosphere in a clean room in the manufacturing process of liquid crystals, semiconductor elements, etc. Since it is too long, continuous monitoring cannot be performed, and even if the atmosphere in the clean room is contaminated by impurities other than fine particles, the work is performed without being able to detect it.
There is a problem that it is impossible to prevent the generation of defective products.

[0012]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems. The concentration of fine particles and impurities in the atmosphere in a clean room is almost independent of the sizes of the fine particles and impurities. It is an object of the present invention to provide an atmospheric impurity monitoring device and an atmospheric impurity monitoring method that are capable of automatic, rapid, and continuous measurement, are easy to handle, and are inexpensive.

[0013]

An airborne impurity monitoring apparatus according to the present invention comprises at least one sealable impurity trapping container, and an ultrapure water introduction line for supplying ultrapure water to the impurity trapping container. An atmosphere ventilation line for aerating the atmosphere in the clean room to sample water in the ultrapure water supplied to the impurity trap, an exhaust line for adjusting the pressure in the impurity trap, and the sample water for the impurities A discharge line for discharging the sample water to the outside of the trapping container, a measuring device for atomizing and rapidly drying the sample water to suspend the impurities in the sample water in the form of fine particles to optically measure the impurity concentration, and the measurement from the impurity trapping container. A sample water introduction line for introducing the sample water into the device, an output device for outputting the measurement result of the measuring device, a recording device for recording the measurement result, each line, the measuring device, It is characterized by a serial output device and the recording device and a control device for controlling according to a predetermined procedure.

That is, in the airborne impurity monitoring device of the present invention, a preset amount of ultrapure water is supplied to at least one sealable impurity trapping container through the ultrapure water introducing line. Next, a certain amount of the atmosphere in the clean room is aerated through the atmosphere ventilation line into the ultrapure water supplied to the impurity trapping container to generate sample water. At this time, the pressure in the impurity trapping container is adjusted by the exhaust line, so that the ultrapure water is supplied into the impurity trapping container and the atmosphere in the clean room is ventilated into the ultrapure water without delay. Then, the generated sample water is introduced into the measuring device for measuring the impurity concentration through the sample water introducing line and measured, and the measurement result by the measuring device is output to the output device and further recorded in the recording device. And
The sample water in the impurity trap that was not used for measurement is
Although it is discharged to the outside of the impurity trap container through the discharge line,
It can be secured if necessary. These series of operations are controlled by the control device, and the control contents can be appropriately set depending on the usage environment of the atmospheric impurity monitoring device. Here, the “impurity” means fine particles in the clean room atmosphere or water-soluble impurities other than the fine particles (metal ions, anions, organic substances, etc.).

It suffices that at least one impurity trapping container is used in the airborne impurity monitoring device of the present invention. However, by increasing the number of impurity trapping containers, the impurities in the clean room atmosphere can be measured in a shorter measurement cycle. It is also possible to monitor impurities and further to monitor impurities in a plurality of clean room atmospheres.

As ultrapure water to be supplied to the impurity trapping container, for example, one having a sufficiently high specific resistance of about 18.0 MΩ · cm (converted at 25 ° C.) and a sufficiently low impurity concentration of silica, organic substances and the like. To use. By doing so, the sensitivity of the measurement result by the measuring device can be improved.

The arrangement of the impurity trapping container and each line is not particularly limited as long as the above function is achieved. However, for example, if one end of the atmosphere ventilation line (atmosphere vent) reaches the vicinity of the bottom of the impurity trap and the atmosphere is blown into the ultrapure water from near the bottom of the impurity trap, impurities in the atmosphere This is preferable because the efficiency of capturing The exhaust line may be installed on the side surface of the impurity trapping container, but it is more preferable to install it on the upper surface of the impurity trapping container because it is possible to reliably prevent the inflow of ultrapure water into the impurity trapping container into the exhaust line. .
The exhaust line is normally evacuated by a pump, but if the pressure fluctuation in the impurity trap is sufficiently small or the air flow rate into the impurity trap can be kept constant, use an aspirator or clean room. It is also possible to use a laid concentrated vacuum line or the like.

Normally, an automatic valve driven by an air-operated system or an electromagnetic system is installed in each line as needed, and the opening / closing of each valve is controlled by a signal from a control device. The structure of such a valve is
For example, unlike diaphragm type, less elution of impurities,
And it is desirable that there is no dead space.

The material of the impurity trapping container and the parts (pipes, valves, etc.) used in each line are high-purity quartz, PEEK (polyether ether ketone), PVDF (polyvinylidene fluoride) or tetra- It is preferable to use a fluorinated ethylene resin or the like. here,
In the impurity trap container and each line, it is only necessary to prevent the elution of impurities from the surface and the adhesion of impurities, so only the surface part where ultrapure water, the atmosphere in the clean room or the sample water comes into contact is coated with Teflon resin, etc. The structure may be the same as the above.

Furthermore, the upper surface of the impurity trapping container has a conical shape or a dome shape, and the ultrapure water is sprayed from the outlet of the ultrapure water introducing line uniformly toward the upper surface of the impurity trapping container in the direction of 360 degrees. With the structure, the supplied ultrapure water flows along the inner wall surface of the impurity trap container, and the remainder of the sample water adhering to the inner wall surface can be effectively washed away, which is preferable. As such a structure, a structure in which a reflecting plate is attached near the outlet of the ultrapure water introduction line and the introduced ultrapure water is dispersed can be adopted. Also, in order to wash away even the sample water remaining on the surface of the piping of the atmosphere ventilation line in the impurity trap, if it is used together with the method of filling the entire impurity trap with ultrapure water, the residue in the impurity trap will remain in a short time. It is more preferable because the impurity concentration can be reduced.

As a measuring device for measuring the concentration of impurities in the generated sample water, the sample water is atomized and rapidly dried to suspend the impurities present in the sample water in the form of an aerosol.
Measuring device for optically measuring impurity concentration (Japanese Patent Publication No. 6-16
The apparatus for measuring in-liquid impurities disclosed in 3961) is used. However, as long as it is a measuring device using the principle of optically measuring the impurity concentration by suspending the impurities existing in the sample water in the form of aerosol, it is disclosed in Japanese Patent Publication No. 6396/1994.
It is not limited to the measuring device disclosed in No. 1.

When the impurity trapping container and the measuring device are integrated with each other, the sample water introducing line can be shortened, and therefore the volume of the sample water introducing line becomes small. Therefore, it is necessary to introduce the sample water into the measuring device. It is preferable because the time becomes as short as possible and the measurement cycle is shortened when the measurement is repeated continuously.

The control device is provided with a function of correcting the measurement result of the measuring device and comparing the correction result with a predetermined reference, in addition to the main purpose of simply controlling the operation of the entire airborne impurity measuring and monitoring device. be able to.

The output device can output not only the measurement result of the measurement device and the correction result based on the measurement result, but also the operation status of the atmospheric impurity monitoring device, for example. Examples of such output devices include printers and CRs.
T etc. are mentioned.

The recording device records the operating condition of the entire atmospheric impurity monitoring device and the measurement result and correction result of the measuring device using a plotter, a printer, magnetism, an optical recording medium, or the like.

Further, when a pressure line for pressurizing the inside of the impurity trap of the airborne impurity monitoring device of the present invention is installed, the sample water is introduced from the impurity trap container to the measuring device through the sample water introduction line only by the water head pressure. The introduction speed can be increased as compared with the case of introduction, and at the same time, the speed of discharging the excess sample water can be increased, which is preferable for shortening the measurement cycle. At this time, if a method of pressure-feeding with supply pressure of high-purity nitrogen or the like is used, not only the introduction speed of the sample water can be increased, but also the sensitivity and accuracy of the measurement result can be improved.

Furthermore, in order to keep the amount of ultrapure water supplied into the impurity trapping container of the airborne impurity monitoring device constant, an adjustment line is provided in the impurity trapping container or a mechanism for measuring the amount of ultrapure water is installed. Is possible.

When the adjustment line is installed, it is usually sufficient to install the adjustment line in accordance with the water level position in the impurity trap container corresponding to a predetermined amount of ultrapure water.

As a mechanism for measuring the amount of ultrapure water,
There are a mechanism for detecting the water level in the impurity trapping container by a sensor, a mechanism for measuring the amount of ultrapure water in the impurity trapping container, a mechanism for detecting the pressure at a predetermined position of the impurity trapping container, and the like. For example, as a liquid level measuring method for detecting the water level in an impurity trap container, in addition to an optical sensor, carbon dioxide gas in the atmosphere is trapped in ultrapure water by venting the atmosphere, and the specific resistance of the sample water is reduced. The electrostatic sensor can be used since Furthermore, if the sensor is movable up and down and the position of the sensor is measured using a potentiometer or the like, highly accurate liquid level measurement can be performed. It is also possible to use the adjustment line and a mechanism for measuring the amount of ultrapure water together.

Further, the method for monitoring impurities in the air according to the present invention comprises a water supply step of supplying ultrapure water into the impurity trap container,
An atmosphere capturing step of aerating the atmosphere in a clean room into ultrapure water in the impurity trapping container to obtain sample water, and atomizing and rapidly drying the sample water to suspend impurities in the sample water in the form of fine particles to optically Further, it is characterized by including a measuring step of measuring the impurity concentration and a judging step of comparing the measurement result measured by the measuring step with a preset standard.

That is, in the method for monitoring impurities in the air according to the present invention, ultrapure water is first supplied into the impurity trap container. Next, the atmosphere in the clean room is aerated with the ultrapure water in the impurity trapping container to generate sample water. Next, the sample water is atomized and rapidly dried, and the impurities in the sample water are suspended in the form of fine particles to optically measure the impurity concentration. Then, the measurement result is compared with a preset reference value.

In the present invention, it is possible to automatically and continuously repeat the atmospheric impurity monitoring method, and in this case, a regular monitoring system is provided. It should be noted that when the method for monitoring impurities in the air of the present invention is repeated, the step of cleaning the device such as the impurity trapping container is naturally performed. However, the cleaning process of the impurity trapping container can be performed only when the impurity concentration in the sample water is high, and can be omitted when the impurity concentration is low.

In the method for monitoring impurities in the air according to the present invention,
After comparing the measurement result with a preset reference value, it is possible to carry out a normal chemical analysis process or the like.

For example, when the measurement result is larger than the preset reference value, the air impurity monitoring method of the present invention is repeated again for confirmation, and the measurement result is compared with the preset reference value. Alternatively, a part of the sample water may be collected and subjected to a more sensitive analysis. Further, when the measurement result is larger than a preset reference value, for example, a configuration is possible in which an external alarm is given by an alarm.

[0035]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings.

It should be noted that the same reference numerals are given to the common parts in the respective drawings, and the duplicate description will be omitted.

(First Embodiment) As a first embodiment, an airborne impurity monitoring apparatus using a single impurity trapping container and an airborne impurity monitoring method will be described with reference to FIGS. 1 and 2.

FIG. 1 (a) is a block diagram showing the outline of the apparatus for measuring the concentration of impurities in the air of the present embodiment. Reference numeral 1 denotes ultrapure water and sample water in which impurities in a clean room are trapped in ultrapure water. Impurity trapping container to be stored, 2a is a pressurizing line for pressurizing the inside of the impurity trapping container 1, 3a is an ultrapure water introducing line for introducing ultrapure water into the impurity trapping container 1, and 4a is an atmosphere for trapping impurities in the clean room. 1. An atmosphere ventilation line for aerating ultrapure water in 1; 5a, an exhaust line having a metering pump for adjusting the pressure in the impurity trap 1; 6a, a fixed amount of ultrapure water introduced into the impurity trap 1. It is a control line for adjusting the temperature of the impurity trapping container 1 and for cleaning the impurity trapping container 1 by overflow cleaning. Further, 7a is a sample water introducing line for introducing the sample water from the impurity trapping container 1 into the measuring device 9, and 8a is a discharge line for discharging ultrapure water or sample water from the impurity trapping container 1 to the outside. The pressurizing line 2a, the ultrapure water introducing line 3a, the atmosphere venting line 4a, the exhaust line 5a, the adjusting line 6a, the sample water introducing line 7a, and the discharging line 8a are for controlling the flow of the circulating substance in the line. Valves 2b, 3b, 4b, 5
b, 6b, 7b and 8b. Reference numeral 9 is a measuring device for measuring the concentration of impurities in the sample water. Here, the sample water is introduced and atomized, the impurities are dried and precipitated, and the suspended particles are optically measured, which is shown in Japanese Patent Publication No. 6-63961. You are using a measuring device that Reference numeral 10 denotes a control device that not only manages and controls the operation of the entire device, but also has a function of correcting the measurement result of the measurement device 9 and comparing the correction result with a predetermined reference value, and 11 indicates the measurement result of the measurement device 9. Is output to a printer and a CRT, and 12 is a record for recording the operating condition of the entire airborne impurity monitoring device and each measurement result and correction result in the measuring device 9 in a storage device using a printer and a magnetic recording medium. It is a device. Reference numeral 13 is a support mechanism that supports the impurity trap container 1.

In the impurity trapping container 1, the tip of the atmosphere venting line 4a reaches near the lower portion of the impurity trapping container 1, and the atmosphere in the clean room is the impurity trapping container 1.
It is ejected from the vicinity of the lower part of the above into the ultrapure water inside, and contributes to increasing the trapping rate of impurities in the ultrapure water. The exhaust line 5a is installed on the upper surface of the impurity trap 1 so that the liquid inside the impurity trap 1 does not flow out from the exhaust line 5a. The exhaust line 5a is connected to a pump (not shown) for exhausting. In addition, the bottom surface of the impurity trap 1 is inclined so that the liquid in the impurity trap 1 is completely discharged, and the sample water introduction line 7a and the discharge line 8a are inclined at the bottom of the impurity trap 1. It is installed at the lower end. The adjustment line 6a is installed on the side surface of the impurity trap 1 and the impurity trap 1
When ultrapure water is supplied to the device, an amount of ultrapure water that exceeds the adjustment line 6a is discharged from the adjustment line 6a, and the amount of ultrapure water supplied to the impurity trapping container 1 is constant (here, 100c.
plays the role of being retained in c). Further, since the ultrapure water introducing line 3a is installed on the upper surface of the impurity trapping container 1, the sample water in the impurity trapping container 1 does not flow back to the ultrapure water introducing line 3a.

Further, Teflon resin piping is used for each line, and the elution of impurities from the line is almost prevented. The diaphragm type is adopted as the structure of each valve.

Further, as a part of shortening the time required for supplying the sample water to the measuring device 9 and aerating the clean room atmosphere, the outer diameter of the sample water introducing line 7a is 6 mm,
The length is 10 cm and the volume of the pipe is about 5 cc. By doing so, the amount of sample water can be reduced to the minimum necessary for impurity concentration measurement, waste of sample water is reduced, and the replacement time of sample water in the pipe during repeated measurement is also shortened. Contributes to the shortening of The piping inside the measuring device 9 is also designed to be shortened as much as possible so that the connection port to the measuring device 9 directly becomes the inlet of the measuring cell.

Further, if atmospheric impurities are captured in a place where the humidity is as low as 30 to 40% (atmosphere in a clean room), the sample water stored in the impurity capturing container 1 decreases, so the impurity capturing container A liquid level meter is added to the inside of 1 to monitor the decrease amount of sample water and automatically supply the same amount of ultrapure water as the decrease amount of sample water, or measure and measure the liquid level at the end of capturing impurities in the air By correcting the value measured by the device 9,
It is possible to perform highly accurate analysis.

As a method of measuring the liquid amount, a method of installing an appropriate liquid level measuring device in the impurity trapping container 1, a method of providing a weight measuring mechanism or a pressure measuring mechanism in the supporting mechanism 13 are relatively simple. The pressure measuring mechanism shown in FIG. 1C is used here.

That is, the container support portion 14 of the support mechanism 13
Is made of resin or metal with the surface covered with resin,
It has a ring shape, and the impurity trapping container 1 is placed in the ring. The container support portion 14 has one mounting portion 15 fixed to the housing 18, and is fixed to the housing 18 via a hinge 16 so as to be movable up and down. On the other hand, a sensor fixing portion 19 having a pressure detection sensor 17 is attached to the housing 18 by a hinge 16.
It is installed directly below the mounting portion 15 on the side of the container supporting portion 14. This allows the pressure detection sensor 17 to detect a change in the weight of the impurity trapping container 1.
At this time, all the pipes from the impurity trap 1 are made to have a space in the vertical direction with the surrounding equipment, the supply / drainage mechanism, etc. so as not to support the weight of the impurity trap 1. Highly accurate measurement is possible.
It goes without saying that various mechanisms other than those shown here can be used when using the pressure sensor.

Next, the method for monitoring atmospheric impurities of the present invention using the apparatus shown in FIG. 1 will be described with reference to FIG. 2 and Table 1.

FIG. 2 (a) is a flow chart showing the method for monitoring airborne impurities in this embodiment, and Table 1 shows the open / closed states of the valves of the piping line in this embodiment. In addition, in Table 1, a blank column indicates that the valve is closed.

[0047]

[Table 1] First, before starting monitoring of impurities in the air, the impurity trapping container 1, the sample water introducing line 7a, etc. are thoroughly washed, and the ultrapure water introduced into the impurity trapping container 1 is cleaned from the impurity trapping container 1 and each line. Make sure there is no mixture of. And
The inside of the impurity trap container 1 is filled with nitrogen gas having a sufficiently low impurity concentration.

In the water supply step 101, the valves 3b and 6b are opened, and ultrapure water is introduced into the impurity trap container 1 through the ultrapure water introduction line 4. In this embodiment, the introduction time of ultrapure water is 1 minute, and 100 cc of ultrapure water is introduced into the impurity trap container 1. Here, the time required to supply 100 cc of ultrapure water to the inside of the impurity trapping container 1 depends on the pressure of the ultrapure water introducing line 3a. Further, the amount of ultrapure water is accurately determined by the position of the adjustment line 6a,
Ultrapure water of cc or more overflows. The ultrapure water introduced into the impurity trap 1 has a specific resistance of 18.0 MΩ · cm.
Since it is sufficiently high (calculated at 25 ° C.) and the concentration of impurities such as silica and organic substances is sufficiently low, relative measurement sensitivity can be improved.

In the atmosphere capturing step 102, the valves 4b and 5 are
b is opened and the inside of the impurity trap 1 is depressurized by the pump through the exhaust line 5a, so that the ultrapure water in the trap 1 is ventilated in the atmosphere of the clean room. Usually, the atmosphere in the clean room, which is aerated with ultrapure water contained in the impurity trapping container 1, has a flow rate of about 1 to several liters / minute by using a suction metering pump or the like, and an operating time of 1
It is desirable to ventilate for about 5 to 90 minutes to trap impurities in the air. The conditions for trapping such impurities in the air can be changed at any time depending on the clean level of the clean room and the expected impurity concentration in the measurement atmosphere.

In this embodiment, the pressure in the exhaust line 5a was set to about 0.8 atm, and ventilation was performed at 1000 cc / min for 15 minutes. In this way, the atmosphere in the clean room is aerated with the ultrapure water in the impurity trap container 1, and the impurities in the atmosphere are trapped in the ultrapure water. The ventilation rate and the ventilation time of the atmosphere in the clean room can be set to appropriate values depending on the amount of contamination in the clean room and the desired detection sensitivity.

In the measuring step 103, the valve 4b and the valve 7b are
Is opened and the sample water is introduced into the sample water introduction line 7a by the head pressure.
Is introduced into the measuring device 9 through. The ultrapure water introduced into the measuring device 9 is atomized into a mist and passed through a metal tube heated to about 120 ° C. to remove water. The obtained aerosol (fine particles of evaporation residue) is mixed with high temperature saturated alcohol vapor to expand the particle size by the nuclear condensation action, and the number is measured by the light scattering method using a laser light source. Then, the measured value is sent to the control device 10, is output to the output device 11, and is recorded in the recording device l2.

In the judgment step 107, the result measured in the measurement step 103 is compared with a reference value a preset for judging the cleanness of the atmosphere, and the cleanness is judged.

Here, when the measurement result is larger than the reference value a, the cleanness is recognized to be abnormal, an alarm is issued, and the measurement cycle (the operation of the entire atmospheric impurity monitoring device) is stopped. Then, clarify the cause of pollution and take appropriate measures.
In particular, when it is necessary to identify contaminants, precision chemical analysis of the rest of the sample water to identify impurity species is a great clue in promoting measures to prevent recurrence of contamination.

On the other hand, if the measurement result is equal to or less than the reference value a and equal to or less than the reference value b for determining that the quality of the supplied ultrapure water is sufficient, the cleanliness is determined to be normal. Then, the next measurement cycle starting from the water supply step 101 is started.

However, when the measurement result exceeds the reference value b for judging that the quality of the supplied ultrapure water is sufficient, the ultrapure water with a low impurity concentration is newly stored in the impurity trap container 1. Need to be introduced. Therefore, the sample water in the container is discharged and the ultrapure water is supplied. At this time, if the sample water containing a high concentration of impurities adheres to the inner wall of the impurity trapping container 1, even if only ultrapure water is supplied, the state of low impurity concentration cannot be realized before venting the atmosphere. Since it becomes difficult to perform highly sensitive measurement, it is necessary to clean the inside of the impurity trap container 1.

Therefore, in washing the container, first, the valve 4b and the valve 8b are opened in the drainage step 104, and the sample water in the impurity trapping container 1 is discarded through the discharge line 8a.
At this time, the valve 2b is further opened to pressurize the inside of the impurity trap 1 so that the discharge rate of the ultrapure water inside the impurity trap 1 is increased and the time required for the drainage step 104 is shortened. When adopting such a pressure feeding system, the pressure line 2a on the upper surface of the impurity trapping container 1 is used.
Therefore, high-purity nitrogen having a pressure of about 2 kg / cm ² is supplied through the valve 2b.

Subsequently, in the cleaning water supply step 105, in order to supply ultrapure water for cleaning the inner surface of the impurity trap 1 to the impurity trap 1, the valve 3b, the valve 6b and the valve 7b.
Then, the ultrapure water is introduced into the impurity trap container 1 through the ultrapure water introduction line 3. Then, a predetermined amount (here, 120 cc) of ultrapure water is supplied, and the ultrapure water overflows from the adjustment line 6a. At this time, the valve 6b is opened is
This is for expelling the sample water staying inside the sample water introduction line 7a. In this way, the ultrapure water larger than the water supply amount in the water supply step 101 is supplied into the impurity trapping container 1 by supplying water until the ultrapure water is discharged from the adjustment line 6a, and also cleaning the inner surface of the adjustment line 6a. This is because.

After that, in the cleaning measurement step 106, the valve 4b and the valve 7b are opened, and the impurity concentration in the introduced ultrapure water is measured. Also at this time, the valve 2b is further opened, the inside of the impurity trapping container 1 is pressurized, the discharge rate of the ultrapure water inside the impurity trapping container 1 is increased, and the cleaning measurement step 106 is performed.
It takes less time.

Then, in the cleaning determination step 108, it is confirmed that the inside of the impurity trap container 1 has been cleaned.

That is, the measured impurity concentration is compared with a reference value b which is sufficiently smaller than the measured value of the impurity concentration in the clean room atmosphere, and when the measurement result is smaller than the reference value b, it is consumed by the measurement. In order to supplement the generated ultrapure water, the process proceeds to the water supply step 101, and the following atmosphere capturing step 1
02, and measurement step 103 are sequentially repeated.

When the impurity concentration detected in the cleaning measurement step 106 is equal to or larger than the reference value b, the ultrapure water in the impurity trap 1 moves to the drainage step 104 again to discard the ultrapure water. The valve 5b is opened and the ultrapure water in the impurity trap container 1 is discharged. After that, the cleaning water supply step 105 is performed again, and the impurity trapping container 1 is filled with ultrapure water, and these are repeated until the impurity concentration in the ultrapure water becomes a value smaller than the reference value b.

However, if the number of times of cleaning of the impurity trapping container 1 is empirically known, the cleaning measurement step 106 may not be performed every cleaning water supply step 105, and the cleaning is repeated a predetermined number of times. After that, when the impurity concentration in the ultrapure water is measured for confirmation, or when the difference between the impurity concentration measured in the measurement step 103 and the reference value b is extremely small, the cleaning measurement step 106 may be performed in some cases. It can be omitted. In this way, when it is confirmed that the impurity concentration in the ultrapure water supplied into the impurity trapping container 1 is so low as to be practically negligible (the reference value b or less), the process moves to the next measurement cycle, and the water supply step is performed. 101, atmosphere capturing step 102 and subsequent steps are repeated. Further, as described above, when the measured value measured in the determination step 107 is smaller than the reference value b, the drainage step 104,
The cleaning water supply step 105, the cleaning measurement step 106, and the cleaning determination step 108 jump back to the water supply step 101 and enter the next measurement cycle, thereby shortening the measurement cycle when the measurement of impurities in the air is continuously performed. Therefore, continuous monitoring of atmospheric impurities can be performed.

As described above, for the purpose of preventing the influence of continuous measurement in the impurity trap container 1, before the step of trapping the impurities in the air, the step of cleaning by repeating the introduction and drainage of ultrapure water several times, It goes without saying that introducing high-purity nitrogen and maintaining it in a normal atmosphere is effective when more accurate measurement is required.

Further, in the present embodiment, the impurity trap container 1
And a series of equipment attached to this was arranged on the upper part of the measuring device, and the method of supplying the sample water in which the atmospheric impurities were captured to the measuring device by the head pressure was used. It is also possible to use a method in which high-purity nitrogen is supplied and pressure is fed by the pressure. That is, at the time of switching such as when shifting to the cleaning measurement step 108 after the cleaning water supply step 105, the valve 2b is temporarily opened to pressurize the inside of the impurity trapping container 1, thereby piping after the valve 7b. In addition to shortening the time required for the drainage process 104 for discharging residual water inside, the measurement process 103
In the above, since the time required for discharging the sample water remaining in the sample water introducing line 7a is also shortened, the measurement cycle can be shortened, and the measurement sensitivity and the measurement accuracy can be improved.

In the present invention, the measurement result measured in the final cleaning measurement step 108 is used as an initial value,
By performing the correction subtracted from the measurement result in the measurement step 103, it is possible to correct the influence of the impurity concentration in the ultrapure water introduced into the impurity trap container 1 before trapping the atmosphere, so that the measurement with higher accuracy can be performed. The result can be obtained.

At this time, such correction is arithmetically processed by the control device 10. Further, even when the impurity concentration before the atmosphere is aerated is higher than the water quality judgment reference value b of ultrapure water, the impurity concentration in the atmosphere can be measured by setting this impurity concentration as an initial value and subtracting it from the measurement result after the atmosphere is aerated. It is also possible to do so.

Next, the same sample water as Na, K, and C was obtained by measuring the atmosphere in the class 1000 clean room by changing the aeration time by the above-mentioned airborne impurity monitoring device.
The results of atomic absorption spectrophotometry of a and Fe are shown in FIG. Here, the value measured by the airborne impurity monitoring device is referred to as the HPM value.

Here, in the measuring device 9 used in this example, not only the four kinds of metallic impurities measured by the atomic absorption photometry but also the total number of fine solid components generated when the sample water is vaporized is measured. Therefore, it is not always completely proportional to the total amount measured by the atomic absorption spectrophotometry. Also, basically, if the measured impurity concentration in the clean room atmosphere is temporally constant, the value measured by the atomic absorption spectrophotometry is proportional to the ventilation time (strictly speaking, the impurity concentration in the sample water is However, since the measured value for each impurity element in FIG. 3 is not perfectly linear, It can be seen that the impurity concentration in the clean room atmosphere varies with time.

Here, referring to FIG. 3, a clear strong correlation is recognized between the measurement results obtained by the airborne impurity monitoring device and the measurement values obtained by the atomic absorption spectrophotometry for each ventilation time. The dependence of the HPM value on the ventilation time also shows the same degree of fluctuation as in the case of the atomic absorption spectrophotometry. Therefore, within this fluctuation range, the HPM value is almost proportional to the ventilation time, and the HPM value of the clean room is It is understood that the value is closely related to the amount of air pollution.

Further, as can be seen from FIG. 3, according to the HPM value, the measured value in the ultrapure water used (initial value before aeration)
Is about 10 to 20 ppb, while class 10
In a clean room of 00, the measured value increases to about 90 to 100 ppb by sampling for 30 minutes.

This means that, for example, in a clean room with a very high degree of cleanliness of about class 1, class 1
If 000-equivalent contamination continues for about 10 minutes, an HPM value of about 30 ppb is obtained, indicating that the occurrence of an abnormality can be detected with sufficient accuracy.

Therefore, as one measurement, the sampling time in the clean room atmosphere is 20 minutes and the measurement time is 5 minutes.
Minutes, the cleaning measurement time is 10 minutes, and even if the drainage time and the like are included, it is possible to set about 40 to 60 minutes per measurement.

As described above, the trace amount of contamination in the clean room atmosphere can be detected by the measurement period of 1 hour or more, which is shorter than the conventional one by one digit or more, and the cause of the contamination can be clarified. It is possible to drastically reduce the number of products that are processed in an abnormal environment.

Furthermore, if the volume of the impurity supplement container 1, the atmosphere aeration rate, and the measurement time are set to conditions more suitable for the operating environment, it is possible to further shorten the measurement cycle and detect low-concentration contamination. Needless to say.

(Second Embodiment) In the above-mentioned air impurity monitoring method, when the judgment in the judgment step 107 is larger than the reference value b and smaller than the reference value a, the drainage step 104, the cleaning water supply step 105, the cleaning measurement step 106, Although the cleaning determination step 108 is repeated, it is also possible to collectively carry out these steps by using the configuration of the airborne impurity monitoring device of the first embodiment. This atmospheric impurity monitoring method will be described with reference to FIG.

In carrying out this method, the upper surface of the impurity trapping container 1 has a conical shape or a dome shape, and the outlet of the ultrapure water introducing line 3 is where the ultrapure water is trapped in the impurity trapping container 1. The structure is such that it squirts out toward the upper surface as uniformly as possible at 360 degrees. Such a structure is shown in FIG.
This will be described with reference to FIG. FIG. 1B shows the structure near the ultrapure water injection port of the ultrapure water supply line 3a on the upper surface of the impurity trapping container 1, and 3b shows the connection of the ultrapure water feed line 3a to the impurity trapping container 1. Mouth, 3c is the impurity supplement container 1
It is a conical reflection plate installed in the vicinity of the ejection port of the ultrapure water introduction line 3a. The reflector 3c is installed in a downward convex direction, and a hole 3d is provided at the tip to avoid water retention.
have. The ultrapure water introduced from the ultrapure water supply line 3a is reflected by the reflection plate 3c at one end inside the impurity supplement container 1 and jetted from the gap 3e, sprayed on the upper surface of the impurity supplement container 1, It flows along the inner surface of 1 to the lower part, and is configured to wash away the rest of the sample water containing impurities on the wall surface of the impurity supplement container 1. According to this method, the sample water containing impurities remaining on the surface of the piping of the atmosphere ventilation line 4a inside the impurity supplement container 1 cannot be completely washed away, so that the impurity supplement container 1 is filled with ultrapure water. In this way, the impurity concentration inside the impurity trapping container 1 can be reduced in a short time. FIG. 2B is a flow chart showing the method for monitoring the airborne impurities in the present embodiment. Since the water supply process 101 to the determination process 107 are the same as those in the above embodiment, the description thereof will be omitted.

By the judgment of the judgment step 107, the measuring device 2
When it is determined that the measurement result by the method is larger than the reference value b and smaller than the reference value a, the following steps are performed as the container cleaning step 110.

First, after the ultrapure water in the impurity supplement container 1 is almost completely discharged, in the container cleaning step 110, the valve 3
b, 6b, 7b and 8b are opened, and while introducing ultrapure water, the measuring device 9 measures the impurity concentration in the ultrapure water flowing in the impurity trapping container 1. Then, when the measurement result reaches a predetermined sufficiently small value, here the reference value b or less, the container cleaning step 110 is ended.

Then, returning to the water supply step 101, the measurement of the impurities in the air is continuously performed again, and the impurities in the air are constantly monitored.

In the above-mentioned embodiments, carbon dioxide gas in the sample water does not become evaporation residue, so the carbon dioxide concentration cannot be detected by the measuring device. Regarding such impurities of gas components, for example, sulfur sulfide can be detected, and ammonia gas (ammonium ion) or the like produces ammonium salts that become evaporation residues in the ultrapure water introduced into the impurity trapping container 1. It has also been confirmed that detection can be performed by adding a small amount of an additive (for example, nitric acid) that has been added.

Therefore, in addition to the metal element that causes the reliability of the gate oxide film and the junction leakage current, the concentration of ions in the atmosphere that causes the dimensional controllability of the chemical breeding type photoresist is monitored. It is possible to carry out the above, and it is obvious that it has a great effect on the cleanliness monitoring of the clean room.

(Third Embodiment) As a third embodiment of the present invention, an airborne impurity monitoring device using two impurity traps 1 and an airborne impurity monitoring method using the device will be described with reference to FIGS. This will be described using 5.

FIG. 4 is a diagram showing the structure of the airborne impurity monitoring apparatus according to this embodiment. In the figure, the size and shape of each component are the same as those of the first embodiment, and the basic structure is the same as that of the first embodiment except that two impurity traps 1 are used. It is no different from the device.

Measuring device 9, control device 10, output device 11
The recording device 12 and the recording device 12 each have only one
The two sample water introduction lines 7 a meet at the entrance of the measuring device 9. The sample water introduction line 7a is branched from the side of the discharge line 8a, and the distance between the branched portion of the discharge line 8a and the sample water inlet of the measuring device 9 is made small. The biggest problem in providing the two impurity trapping containers 1 is to reduce the volume of the sample water introducing line 7a. In this embodiment, the volume of the sample water introducing line 7a is easily improved by devising the arrangement of the vessels and adopting the above-mentioned configuration. Moreover, it was possible to obtain the same degree as in the first embodiment.

Next, a method for monitoring atmospheric impurities using the apparatus shown in this embodiment will be described with reference to FIG.

FIG. 5 (a) shows that when the measurement cycle is steadily repeated in the method for monitoring impurities in the air of the present embodiment,
It is a timing diagram which shows the state of each impurity trapping container 1 for every 1 cycle. Here, one of the two impurity trapping containers 1 is tentatively called a container a, and the other one is called a container b.
Further, the horizontal axis represents time, and it is assumed that time elapses from left to right, and the contents of process names in the figure are as shown in the first embodiment. However, the container cleaning step 1 in this embodiment
The process 10 comprises the drainage process 104 and the cleaning and water supply process 105 in the first embodiment, or the container cleaning process 110 does not include the cleaning determination process 108 using the measuring device 9. In addition, first, ultrapure water introduction line 3
It is assumed that the insides of the two impurity trapping containers 1 are sufficiently washed with the ultrapure water introduced from a and the same amount of the ultrapure water as in the first embodiment is filled.

At time t0, the container a is in the container cleaning step 110.
Rush into. During this period, the container b is in the measurement step 103 for measuring the impurity concentration in the sample water in which the impurities in the atmosphere are captured in the previous cycle.

At time t1, the container a shifts to the cleaning measurement step 106 for confirming that the inside of the container a has been cleaned, and the impurity concentration before aeration of the atmosphere is measured as the background. During this time, the container b is the container cleaning step 110.
In, the inside is cleaned. In the case of this embodiment, the initial value as the background is measured,
As an initial value, the container cleaning time (number of times of water replacement) required to sufficiently reduce the impurity concentration is empirically determined.

At time t2, the container a is in the water supply process 1
Immediately after replenishing the amount of ultrapure water spent for measurement in 01, the atmosphere capture step 102 is entered at time t3, and the atmosphere in the clean room is introduced into the ultrapure water in the container. During this time, the container b is in the cleaning measurement step 106, and the background impurity concentration is measured.

From time t4, the container a is measured in the measuring step 103.
Then, the concentration of impurities in the sample water in which the impurities in the atmosphere are captured is measured. During this time, the container b is replenished with the extremely small amount of ultrapure water consumed in the cleaning measurement process 106 in the water supply process 101, and the atmosphere capturing process 102 is performed at time t5.

Here, in order to match the measurement accuracy of the container a and the container b, time (t1-t0), (t2-t1),
(T4-t2) and (t0-t4) are made equal. Therefore, as compared with the first embodiment, the measurement cycle can be shortened to 1/2. Note that here, the measurement cycle of the container b is delayed by ¼ cycle with respect to the container a, but it is needless to say that the same effect can be obtained by delaying by 3/4 cycle.

In the evaluation of the measurement results thus obtained, the measurement values obtained from the sample water are sent to the control device 10 and recorded in the recording device 12, and are corrected by the background measurement results. It is recorded in the recording device 12. Then, the measurement result and the correction value are output to the output device 11 and the correction value is stored in the control device 10 in advance in the control device 10 in the same manner as in the flowcharts of FIGS. 2A and 2B. It is the same as in the first embodiment in that it is compared with the reference value a and the following steps are repeated.

(Fourth Embodiment) Next, another impurity concentration monitoring method in the atmosphere in the clean room using the airborne impurity monitoring device of the third embodiment will be described with reference to FIG. 5 (b). .

FIG. 5 (b) shows the case where the measurement cycle is steadily repeated in the method for monitoring impurities in the air according to the present embodiment.
It is a timing diagram which shows the state of each impurity trapping container 1 for every 1 cycle. Here, one of the two impurity trapping containers 1 is tentatively called a container a, and the other one is called a container b.
Further, the horizontal axis represents time, and it is assumed that time elapses from left to right, and the contents of process names in the figure are as shown in the first embodiment. However, the container cleaning step 1 in this embodiment
10 includes the drainage process 104 and the cleaning water supply process 105 in the first embodiment, or the container cleaning process 110 does not include the cleaning determination process 108 using the measuring device 9. In addition, first, ultrapure water introduction line 3
It is assumed that the inside of the two impurity trapping containers 1 is sufficiently washed with the ultrapure water introduced from a.

At time t0, the containers a and b enter the water supply step 101, and the same amount of ultrapure water as in the first embodiment is supplied to the container a.
And the inside of the container b.

Subsequently, the atmosphere capturing step 102 is performed from time t1 to time t2.

At time t2, the container a is measured in the measuring step 10.
Moving to 3, the measurement of the impurity concentration in the sample water that has absorbed the impurities in the atmosphere is carried out. During this time, the container b is sealed and the sample water inside is preserved. This is because when an abnormality occurs in the measurement result of the container a, the sample water in the container b is analyzed in detail and the cause of the abnormality is clarified. From time t3, the container a and the container b enter the container cleaning step 110. However, the measuring device 9 checks only the cleanliness inside the container a, and does not check the cleanliness inside the container b. That is,
Since the size and shape of the container b are the same as those of the container a, the cleanliness inside the container b can be obtained in the same manner as inside the container a by keeping the cleaning time and the flow rate of ultrapure water equal.

In the first embodiment, when it was judged that the measured value in the measuring step 103 was abnormal, the sample water remaining after the measurement was used for the precision analysis. However, if the remaining amount of sample water is small, it may interfere with precision measurement, but by installing a separate container in this way, it is possible to secure a sufficient amount of sample water for precision measurement. . Further, according to this embodiment, not only the sample water is secured, but also the impurity trapping container 1 can be downsized, so that the time required for venting the atmosphere can be shortened.

In the atmospheric impurity monitoring method of this embodiment, since the impurity concentration in the sample water in the container b is not measured, it is not necessary to connect the container b to the measuring device 9 and the container b is not required. Therefore, it is possible to omit the sample water introduction line 7a.

Further, in this embodiment, two impurity trapping vessels 1 are installed, but for example, two impurity trapping vessels 1 are provided.
In addition to the configuration for alternately measuring the impurity concentration, two or more impurity trapping containers 1 are provided depending on the monitoring environment and monitoring method, such as one or two containers for securing sample water for analysis in the event of an abnormality. Needless to say, can be installed.

[0101]

In the air impurity measuring apparatus of the present invention, the sample water is introduced into the measuring apparatus from at least one sealable impurity trap, and the sample water is atomized and rapidly dried to remove impurities in the sample water. Since a device for optically measuring the impurity concentration by suspending particles in the form of fine particles is applied, the concentration of fine particles and impurities (metal ions, anions, organic substances, etc.) in the atmosphere in a clean room can be adjusted to It is possible to provide an atmospheric impurity measuring device capable of performing a constant measurement of atmospheric impurities in the case of performing continuous measurement automatically and irrespective of the size, in a quick and simple manner. Further, in the method for measuring impurities in the air of the present invention, the ultrapure water in the impurity trapping container is aerated with an atmosphere in a clean room to form sample water, and the sample water is atomized and rapidly dried so that impurities in the sample water are fine particles In order to compare the measurement result with a reference value set in advance by optically measuring the impurity concentration by suspending the particles in the shape of particles, the particles in the atmosphere in the clean room and impurities in the atmosphere (metal ions,
It is possible to provide a method for measuring an atmospheric impurity that allows the concentration of anions, organic substances, etc.) to be measured quickly and simply, regardless of the size of fine particles or impurities.

As a concrete example, at the manufacturing site of a semiconductor device or the like, the measurement is performed until it is determined that an abnormality occurs, as compared with the case where the atmosphere control in the clean room is performed by the conventional impurity concentration measuring method. Time is 1/10
Since it can be shortened to the extent, it is possible to reduce the amount of products processed in an abnormal environment to about 1/10.

Furthermore, since the time from the occurrence of an abnormality until the abnormality is identified is shortened, the cause of the abnormality can be immediately clarified when the abnormality is identified. It becomes extremely easy to take measures to prevent recurrence.

That is, by carrying out the present invention,
By immediately detecting that the atmosphere in the clean room is contaminated by impurities other than fine particles, it is possible to prevent the occurrence of defective products and at the same time take measures to prevent abnormal atmosphere. Thus, it is possible to reduce the chances of stopping the line to take measures against abnormalities.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing an outline of an airborne impurity monitoring device according to first and second embodiments.

FIG. 2 is a flow chart showing an atmospheric impurity monitoring method in the first and second embodiments.

FIG. 3 shows the results of measuring the atmosphere in a class 1000 clean room by changing the aeration time and using the same sample water as N.
The figure which showed the result measured by the atomic absorption photometry about a, K, Ca, and Fe.

FIG. 4 is a configuration diagram showing an outline of an airborne impurity monitoring device according to third and fourth embodiments.

FIG. 5 is a timing chart showing a state of each impurity trapping container 1 for each cycle when the measurement cycle is regularly repeated.

[Explanation of symbols]

l ... Impurity capturing container Container 2a ... Pressurizing line 3a
...... Ultrapure water introduction line 4a …… Atmosphere ventilation line 5a …… Exhaust line 6a
...... Adjustment line 7a …… Sample water introduction line 8a …… Discharge line 9 ...
… Measuring device 10 …… Control device 11 …… Output device 12 …… Recording device 13 …… Supporting mechanism 14 …… Container supporting part 15 …… Mounting part 16 …… Hinge 17 …… Pressure detecting sensor 18 …… Housing 19 ...... Sensor fixed part

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Seiichi Inagaki 2-9-8 Okada, Atsugi-shi, Kanagawa Nomura Micro Science Co., Ltd. (72) Inventor Takashi Mizuta 2-9-8 Okada, Atsugi, Kanagawa No. Nomura Micro Science Co., Ltd. (72) Inventor Motonori Yanagi 2-9-8 Okada, Atsugi City, Kanagawa Nomura Micro Science Co., Ltd.

Claims (7)

[Claims] 1. At least one sealable impurity trapping container, an ultrapure water introduction line for supplying ultrapure water to the impurity trapping container, and ultrapure water supplied to the impurity trapping container in a clean room. Atmosphere venting line for venting the atmosphere to sample water, an exhaust line for adjusting the pressure in the impurity trapping container, a discharge line for discharging the sample water out of the impurity trapping container, and a fog for the sample water Measuring apparatus for suspending impurities in the sample water in a fine particle form by optical drying to measure the impurity concentration optically, and a sample water introducing line for introducing the sample water from the impurity trap container to the measuring apparatus, An output device that outputs the measurement result of the measurement device, a recording device that records the measurement result, and the lines, the measurement device, the output device, and the recording device according to a predetermined procedure. Airborne impurities monitoring apparatus characterized by comprising a control for controlling devices. 2. The airborne impurity monitoring device according to claim 1, further comprising a pressurizing line for pressurizing the inside of the impurity trapping container. 3. The air according to claim 1 or 2, wherein a reflection plate for dispersing the introduced ultrapure water is provided near the ultrapure water introduction port of the ultrapure water introduction line. Impurity monitoring device. 4. The airborne impurity monitoring device according to claim 1, further comprising a control line for controlling a supply amount of ultrapure water supplied into the impurity trapping container. 5. The airborne impurity monitoring device according to claim 1, further comprising a measuring mechanism for measuring the amount of ultrapure water supplied into the impurity trapping container. 6. The airborne impurity monitoring apparatus according to claim 5, wherein the measuring mechanism is a liquid level measuring mechanism, a weight measuring mechanism or a pressure measuring mechanism. 7. A water supply step of supplying ultrapure water into the impurity trapping container, an atmosphere trapping step of aerating the ultrapure water in the impurity trapping container with an atmosphere in a clean room to obtain sample water, and the sample water. Compare the measurement result measured by the measurement step with the measurement step of optically measuring the impurity concentration by atomizing and rapidly drying and floating the impurities in the sample water in the form of fine particles, and a preset reference value. A method for monitoring atmospheric impurities, comprising: a determination step.