JPH0381636A - Method for sampling liquid - Google Patents

Abstract

PURPOSE:To facilitate sampling by interrupting the gas supply into a vessel by a 1st piping switching means, stopping the discharge of liquid from the vessel by a 2nd piping switching means, reducing the pressure in the vessel via the 1st piping switching means, sucking the liquid via the 2nd piping switching means and transferring the liquid into the vessel. CONSTITUTION:The front end of the piping 45 is immersed into the liquid chemical 20 in a tank 5. Three-way valves 31, 32 are controlled to discharge the gas 2 remaining in a bottle 4 by a pump 1 and to store a prescribed volume of the chemical liquid into the bottle 4. The valves 32, 31 are controlled to feed gaseous N2 2 of a specified pressure through a pressure valve 7 and to inject the gas into the bottle 4 after dust is removed therefrom by a filter 8 to prevent the foaming of the liquid chemical. The quantity of the fine particles in the liquid chemical 20 is measured by a measuring instrument 6 and the liquid is discharged as a waste liquid 20a via a flow rate control valve 9 and a flow meter 10. The liquid is easily and rapidly sampled according to this method.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a liquid sampling method for measuring fine particles in a liquid.

<Prior Art> Recently, in order to increase the integration of transistors, efforts have been made to make the environment of semiconductor manufacturing equipment clean and free from pollution. There is a need for a method that can make the wafer processing department, which requires particularly high cleanliness, clean at low cost. For this reason, it is necessary to accurately measure the number of fine particles contained in a liquid such as a chemical used in the wafer processing process, and to manage the number of fine particles so that the number is equal to or less than a predetermined number.

A known method for accurately measuring the number of particles in a liquid is to utilize scattering of laser light by particles. However, when measuring fine particles in a liquid, the laser light is scattered by bubbles in the liquid and the bubbles are also counted as fine particles, making it difficult to accurately measure the number of fine particles. Therefore, a method has been proposed in which the particles are measured while pressurizing the liquid in order to prevent foaming in the liquid.

FIG. 2 is a drawing for explaining an example of this method, in which a chemical tank 5 containing a chemical liquid 20 is installed in a sealed container 11, and a gas 2 such as N2 is directed inside the pipe by an arrow. G
The gas is fed under pressure in the direction of , passes through a pressure valve 7 and a gas filter 8 , and is fed into a container 11 . 12 is an exhaust valve for discharging the gas 2 from the container 11. container 1
1 is pressurized by the gas 2, so that bubbles are prevented from forming within the chemical solution 20. Also, due to this pressurization, the chemical solution 2
0 is pushed into the pipe 13 and moved in the direction shown by the arrow H, and the particulate measuring device 6 uses scattering of laser light.
It passes through the flow rate adjustment valve 9 and the flow meter 10 and is discharged as waste liquid 20a. Then, the particle measuring device 6 measures the number of particles in the chemical solution 20 passing through.

<Problems to be Solved by the Invention> However, when measuring fine particles in a chemical solution as described above, the following problems occur.

First, to sample one chemical solution, open the lid (not shown) of the container 11 and place the chemical solution tank 5 inside the container 11.
After inserting the pipe 13 into the container 11 and immersing the tip of the pipe 13 into the chemical solution 20, it is necessary to close the lid of the container 11 and seal the container 11. Therefore, this work takes time.

Next, after the measurement of particulates in the chemical solution is completed, in order to perform the next measurement of particulates in the chemical solution, remove the piping 13 from the container 11, take out the chemical tank 5, insert a new chemical tank into the container 11, and then After immersing the container 13 into the chemical solution in the new chemical solution tank,
It is necessary to put a lid on the container 11 and seal the container 11 again. And this work also takes time.

In this way, even when sampling a single chemical solution,
It takes effort and time to take the chemical solution tank 5 into and out of the container 11. Therefore, when sampling a large number of chemical solutions in sequence, it takes a lot of effort and time, which is troublesome.

The present invention has been devised in view of the above circumstances, and it does not take much time and effort to sample liquids such as chemical solutions, and it is possible to easily sample liquids in any liquid tank. The purpose is to provide a method for sampling liquids.

<Means for Solving the Problems> In order to solve the above-mentioned problems, the liquid sampling method of the present invention includes a pipe for feeding gas into the container to pressurize the liquid in the container and a pipe for discharging the liquid in the container. ,Each,
First and second piping switching means are provided, and when sampling a liquid into a container, the first piping switching means cuts off the supply of gas into the container, and the second piping switching means discharges the liquid from the container. The liquid is sucked into the pipe connected to the container via the second pipe switching means by stopping the system and reducing the pressure inside the container by the suction means connected to the container via the first pipe switching means. and move it into the container.

<Operation> When sampling a liquid into a container, the first piping switching means cuts off the supply of gas into the container, and the second piping switching means stops discharging the liquid from the container. When the pressure inside the container is reduced by the suction means connected to the container via the first piping switching means, the liquid is sucked into the piping connected to the container via the second piping switching means and into the container. Moving.

<Example> Hereinafter, an example of the present invention will be described with reference to the drawings, taking as an example a case where a chemical liquid is sampled as a liquid. FIG. 1 is a drawing for explaining one embodiment of the present invention, and is a block diagram of a sampling system and a particulate measurement system that can realize the method of this embodiment. Note that the same reference numerals are given to the same parts as those described in the related art section.

First, the configurations of the sampling system and particulate measurement system will be explained.

In FIG. 1, reference numeral 4 denotes a sampling bottle that houses the sampled chemical solution 20 and is a sealed container. One end of the pipe 41 is inserted into the upper part of the sampling bottle 4, and the other end is connected to the third opening 313 of the three-way valve 31 (first pipe switching means). three-way valve 3
A pressure valve 7 and a gas filter 8 are provided in the pipe 42 connected to the first opening 311 of the three-way valve 3.
A suction pump 1 is provided in the piping 43 connected to the second opening 312 of the sample bottle 4 as a suction means for reducing the pressure inside the sampling bottle 4 . Note that an exhaust valve 12 is attached to the pipe 41 to allow the gas 2 in the sampling bottle 4 to be exhausted.

One end of the pipe 44 is inserted into the sampling bottle 4 to near the bottom, and the other end is connected to the first opening 321 of the three-way valve 32 (second pipe switching means). three-way valve 3
A pipe 45 is connected to the second opening 322 of 2,
The tip of this piping 45 is inserted into the chemical liquid 20 placed in the chemical liquid tank 5 up to the vicinity of the bottom of the chemical liquid tank 5 . One end of the piping 46 is connected to the third opening 323 of the three-way valve 32, and the other end is connected to the inlet of the particle measuring device 60. The pipe 47 connected to the outlet of the particle measuring device 6 includes
A flow control valve 9 and a flow meter 10 are provided.

Next, a method of sampling the chemical solution 20 and a method of measuring particles in the sampled chemical solution 20 using such a sampling system and a particle measuring system will be described.

First, the tip of the pipe 45 is immersed in the chemical solution 20 up to the vicinity of the bottom of the chemical solution tank 5 . The three-way valve 31 is controlled so that the second opening 312 and the third opening 313 of the three-way valve 31 are electrically connected. Furthermore, the three-way valve 32 is controlled so that the first opening 321 and the second opening 322 of the three-way valve 32 are electrically connected. Next, operation of the suction pump 1 is started.

Then, the air or remaining gas 2 in the sampling bottle 4 is sucked into the pipe 41, and the three-way valve 32 is moved by the arrow A.
After passing in the direction of arrow B, it moves inside the pipe 43 in the direction of arrow B and is discharged from the suction pump 1. Therefore, as the suction pump 1 continues to operate, the pressure in the sampling bottle 4 decreases, and the drug i20 in the chemical tank 5 is sucked into the pipe 45 and passes through the three-way valve 32 in the direction of arrow C. Thereafter, it moves into the sampling bottle 4 via the piping 44. When a predetermined amount of the chemical solution 20 has accumulated in the sampling bottle 4, the operation of the suction pump 1 is stopped.

Next, the first opening 321 and the third opening 32 of the three-way valve 32
The three-way valve 32 is controlled so that the first opening 311 and the third opening 313 of the three-way valve 31 are brought into electrical continuity. Then, when a gas 2 such as N2 is fed under pressure into the pipe 42, the gas 2 passes through the pressure valve 7 to a constant pressure, and then passes through the gas filter 8, where most of the dust and the like contained in the gas 2 is removed. After passing through the three-way valve 31 in the direction of arrow E in this state, it is fed into the sampling bottle 4. The pressure of the gas 2 sent into the sampling bottle 4 applies pressure to the chemical liquid 20 in the sampling bottle 4, preventing foaming within the chemical liquid 20, and the chemical liquid 20 is sucked into the piping 44, and is drawn from three directions. After passing through the valve 32 in the direction of arrow F, the particles are introduced into the particulate measuring device 6 via a pipe 46. The chemical solution 20, whose number of particles has been measured in the particle measuring device 6, passes through the pipe 47, the flow rate control valve 9, and the flow meter 10, and then is discharged from the pipe 47 as a waste liquid 20a. Note that the amount of the chemical liquid 20 sucked into the pipe 44 is adjusted to a predetermined amount by the flow rate control valve 9, and the flow rate of the chemical liquid 20 is measured by the flow meter 10, so that the chemical liquid 20 has a certain amount per unit volume. The number of particles that are present is known.

After this, in order to sample any other chemical solution into the sampling bottle 4, the first opening 311 and the second opening 312 of the three-way valve 31 are brought into communication with each other, and the first opening 321 and the second opening of the three-way valve 32 are brought into communication with each other. After making the opening 322 conductive, the three-way valve 3
Since it is only necessary to operate the suction pump 1 after immersing the pipe 45 connected to the second opening 322 of No. 2 in the chemical solution, sampling of other chemical solutions can be easily performed in a short time.

<Effects of the Invention> As explained above, the liquid sampling method of the present invention includes first and second pipes for feeding gas into the container to pressurize the liquid in the container and piping for discharging the liquid in the container, respectively. When sampling the liquid into the container, the first piping switching means cuts off the supply of gas into the container, and the second piping switching means stops discharging the liquid from the container, By reducing the pressure inside the container by the suction means connected to the container via the first piping switching means, the liquid is sucked into the piping connected to the container via the second piping switching means and into the container. It is being moved.

Therefore, according to the liquid sampling method of the present invention, it is possible to easily sample a liquid in a short time because it does not take time and effort to take a liquid tank containing a liquid into and out of a closed container, which was conventionally required. can. Also, the second
The piping connected to the container via the piping switching means can be immersed in any chemical solution to sample inside the container.
From this point as well, it is possible to enjoy the advantage of being able to easily sample any liquid.

[Brief explanation of drawings]

FIG. 1 is a drawing for explaining one embodiment of the present invention, and is a block diagram of a sampling system and a particulate measurement system that can realize the method of this embodiment. FIG. 2 is a block diagram of a conventional sampling system and particulate measurement system. l...suction pump, 2...gas, 4...sampling bottle, 20...chemical solution, 31.32...
Three-way valve, 41-47...Piping. Figure 1 Figure 2

Claims (1)

[Claims] (1) A first pipe is installed in the pipe that sends gas to the container to pressurize the liquid in the container, and the pipe that discharges the liquid in the container.
and a second piping switching means, and when sampling the liquid into the container, the first piping switching means cuts off the supply of gas into the container, and the second piping switching means stops discharging the liquid from the container. By reducing the pressure inside the container by the suction means connected to the container via the first piping switching means, the liquid is sucked into the piping connected to the container via the second piping switching means, and the liquid is removed from the container. A method for sampling a liquid, characterized in that the liquid is moved into the interior of the liquid.