JP2002031596A - Liquid concentration measuring device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a liquid concentration measuring device capable of measuring the concentration accurately even in the case of wash liquid mixed with air bubbles. SOLUTION: The sizes of the air bubbles are adjusted beforehand by air bubble adjusting means 16, 21 in a measuring liquid flowing into a measuring cell 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid concentration measuring device for measuring the concentration of a liquid and the amount of a composition contained in the liquid.

[0002]

2. Description of the Related Art In a cleaning process of a semiconductor wafer or a liquid crystal substrate, since the oxidation-reduction potential of a cleaning solution and a rinsing solution is important, a cleaning solution having a negative oxidation-reduction potential obtained by dissolving hydrogen gas in ultrapure water is used. A method of cleaning electronic components or a method of dissolving ozone gas in ultrapure water and cleaning with a cleaning liquid having a positive oxidation-reduction potential may be used.

In the method using a liquid in which a gas such as hydrogen gas or ozone is dissolved as a cleaning liquid, the cleaning effect can be further enhanced by irradiating ultrasonic waves during cleaning.

When cleaning is performed using a cleaning solution in which a cleaning function gas such as hydrogen gas or ozone is dissolved in ultrapure water, ultrasonic irradiation is also used. The dissolved cleaning function gas foams (gasifies to generate air bubbles), and if the amount of the cleaning function gas dissolved in the cleaning liquid is reduced, the cleaning effect is reduced. In addition, even if the ultrasonic irradiation amount is appropriate, a good cleaning effect cannot be obtained unless the amount of the cleaning function gas dissolved in the cleaning liquid is sufficient. In any case, in order to obtain a good cleaning effect, it is necessary to appropriately manage the dissolved amount of the cleaning function gas (the concentration of the cleaning liquid) in the cleaning liquid. These controls are performed by measuring the concentration of the cleaning liquid by a measuring method based on an optical spectrophotometric method.

[0005] One example of the measurement by the spectrophotometric method is to irradiate the light from the light emitting section as monochromatic light to the measuring section via a prism or a diffraction grating, and to measure the light when the cleaning liquid as the measuring liquid in the measuring section passes. The amount of absorption is measured by a light receiving unit such as a photoelectric tube or a photomultiplier tube to measure the concentration of the cleaning liquid.

[0006]

However, when the optical method is used for measuring the concentration of the cleaning liquid, accurate measurement is difficult if bubbles are mixed in the cleaning liquid. For example, when a cleaning liquid in which ozone is dissolved is measured by a spectrophotometric method, a numerical value higher than the actual concentration of the cleaning liquid may be detected because bubbles of ozone gas are mixed in the cleaning liquid. This confirms that bubbles having a large particle size have an effect.

The present invention has been made based on these circumstances, and an object of the present invention is to provide a concentration measuring device capable of accurately measuring the concentration of a cleaning liquid containing air bubbles.

[0008]

According to the first aspect of the present invention, a measuring solution is caused to flow into a measuring cell, and the flowing measuring solution is irradiated with light or ultrasonic waves, and the transmitted light or In a liquid concentration measuring device that detects an ultrasonic wave and measures the concentration of the measurement liquid, a bubble adjustment unit is provided for flowing the measurement liquid into the measurement cell and finely pulverizing bubbles mixed in the measurement liquid. It is a liquid concentration measuring device characterized by the above-mentioned.

According to the second aspect of the present invention,
The bubble concentration adjusting means is a gas-liquid separation tower connected to a pressure regulator.

According to the third aspect of the present invention,
The said bubble adjustment means is the liquid concentration measuring apparatus characterized by being the bubble stirring part provided in the said channel.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a liquid concentration measuring device according to the present invention will be described below with reference to the drawings.

First, a liquid concentration measuring cell used in the present invention will be described. FIG. 1 is a schematic explanatory view of one embodiment of a measuring cell, and FIG. 2 is an enlarged sectional explanatory view taken along line AA ′ of FIG.

The measuring cell 1 has a measuring section 2 at the center of the cell body 1a for continuously passing a measuring liquid (such as a cleaning liquid). In the cell body 1a, a measurement liquid flow path 11 for continuously flowing the measurement liquid is formed such that the cross section is a square, an oval, or an ellipse. In a central portion of the cell main body 1a, a translucent member 3 such as a quartz glass or the like is fitted in a water-tight manner via an O-ring 10 on surfaces facing each other across the measurement liquid flow path 11.

Reference numeral 4 denotes an inflow section of the measurement liquid flow path 11 connected to the measurement section 2. The measurement liquid flows continuously from the inflow section 4 and is discharged from the discharge section 5 on the opposite side. A light emitting unit 6 provided with a light source such as a mercury lamp on one side outside of the measuring unit 2
And an optical filter 7 and a light receiving section 8 on the outside on the opposite side.
Is installed. The monochromatic light from the light emitting unit 6 is received by the light receiving unit 8 via the light transmitting member 3 and the optical filter 7. Reference numeral 9 denotes a quartz glass pressing plate fitted on both sides of the measuring section 2.

When the liquid to be measured is highly corrosive, the measuring cell 1 can form at least a pipe and a measuring part whose surface is formed of a corrosion-resistant resin. For example, generally known fluororesins having corrosion resistance include polyethylene tetrafluoroethylene tetrafluoroethylene-perfluoroalkyl vinyl ether polymer (PFA), polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), and polyfluoride. Vinyl (PVF) or the like can be used.

Although the above-mentioned measuring cell optically detects the concentration of the measuring liquid by a combination of a light source and a light receiving element of a light receiving section, an ultrasonic oscillator (not shown) is used instead of the light source. If the light receiving unit is provided with an ultrasonic sensor (not shown), the liquid concentration of the measurement liquid can be measured by an ultrasonic method.

Next, a liquid concentration measuring apparatus of the present invention using the above-mentioned measuring cell will be described.

In the liquid concentration detection of the present invention, it was confirmed by experiments that large bubbles caused measurement errors when measuring the liquid concentration in the measuring cell, and small bubbles had no effect on the measurement errors. Therefore, large bubbles mixed in the measurement liquid are removed by the bubble adjusting means.

FIG. 3 is a block diagram showing a configuration of a liquid concentration measuring device connected to the cleaning device according to the first embodiment, and FIG. 4 is a schematic diagram of the gas-liquid separation column.

That is, in the concentration measuring device 30a, a gas-liquid separation tower 16 is provided as a bubble adjusting means in the middle of a pipe p for supplying a cleaning liquid (measurement liquid) to the cleaning device 15. As shown in FIG. 4, the gas-liquid separation tower 16 is provided with upper and lower output pipes p, the upper pipe p is connected to the pressure regulator 17, and the lower pipe p is connected to the measurement cell. 1
Connected to the input side of The output side of the measuring cell 1 is a pipe p
Is connected to the cleaning device 15 by means of.

With these configurations, the cleaning liquid mixed with large and small bubbles flowing through the pipe p to be supplied to the cleaning device 15 flows into the gas-liquid separation tower 16. In this case, since the liquid level in the gas-liquid separation tower 16 is provided below the inflow port 18, the cleaning liquid flowing into the gas-liquid separation tower 16 is, as shown by an arrow A, in the gas-liquid separation tower 16. It passes through a path that falls from the air (in the gas).

Since the pressure inside the gas-liquid separation tower 16 is controlled to a predetermined pressure by the pressure regulator 17, the gas in the tower is in a constant high-pressure environment. The large air bubbles that have entered are ruptured by high pressure and decomposed into small air bubbles, and the large air bubbles that have entered the cleaning liquid disappear. The cleaning liquid in that state is input to the measurement cell 1.

The cleaning liquid from which large air bubbles have been removed, which has been input into the measuring cell 1, flows into the measuring section 2 of the cell body 1 from the inflow section 4 and is discharged to the opposite discharge section 5 as shown in FIG.
Discharge more. When passing through the measuring section 2, the light flux of monochromatic light from the light emitting section 6 passes through the cleaning liquid, passes through the optical filter 7, is received by the light receiving section 8, and is input to the detection circuit.
Thereby, the concentration of the cleaning liquid is measured.

Next, a description will be given of a second embodiment of the liquid concentration measuring apparatus according to the present invention.

FIG. 5 is a block diagram showing a configuration of a liquid concentration measuring device connected to a cleaning device according to a second embodiment, and FIGS. 6A and 6B are cross-sectional views of a bubble stirring section. FIG. 6C is a schematic cross-sectional perspective view thereof. That is, the concentration measuring device 30b is provided with the bubble agitating section 21 as a bubble adjusting means in front of the measuring cell 1 in the conduit p for supplying the cleaning liquid to the cleaning device 15.

In addition, the bubble stirring section 21 is provided in FIG.
As shown in (b) and (c), in a static mixer system, a partition plate 22 is provided in a pipe p through which washing water flows.
a and 22b are provided adjacent to each other along the direction of the flow of the cleaning liquid at a phase of 90 degrees. This partition plate 22a,
As shown in FIG. 6A, the sectional shape of the partition plate 22b is a gentle S-shaped twisted curved surface.
As for 2a and 22b, a combination in which the phases are shifted from each other by 90 degrees is a pair. FIG. 6 (b) shows a modification thereof, in which the partition plates 22a and 22c are formed so that the twisted directions of the S-shaped twisted curved surfaces are opposite to each other.

The bubble stirring section 21 is provided with these partition plates 22
Using a plurality of pairs of a and 22b, they are continuously arranged in the flow direction of the cleaning liquid, and are formed in multiple stages of about 2 to 5 stages. Further, polytetrafluoroethylene (PTFE) or the like is used as a material of the partition plates 22a, 22b, and 22c.

The output side of the bubble stirrer 21 is connected to the measuring cell 1
Connected to the input side of The output side of the measuring cell 1 is a pipe p
Is connected to the cleaning device 15 by means of.

With these configurations, the cleaning liquid containing large and small bubbles flowing through the pipe p to be supplied to the cleaning device 15 flows into the bubble stirring section 21. In this case, in the bubble stirring section 21, first, the cleaning liquid is supplied to the partition plate 2 in the pipe p.
2a), the cross-sectional area of the conduit p is reduced, and the partition plates 22a and 22b have a gentle S-shaped cross section. When the cleaning is performed, pressure is applied to the cleaning liquid.
This operation is repeated due to the phase shift of the partition plates 22a, 22b, 22c. Due to these pressures, large air bubbles mixed in the cleaning liquid burst and break down into small air bubbles, and the large air bubbles mixed in the cleaning liquid disappear. The cleaning liquid in that state is input to the measurement cell 1.

The cleaning liquid from which large air bubbles have been removed and which has been input into the measuring cell 1 is, as shown in FIG.
The cleaning liquid flows into the measuring section 2 from the inflow section 4 and is discharged from the discharge section 5 on the opposite side. When passing through the measuring section 2, the light flux of monochromatic light from the light emitting section 6 passes through the cleaning liquid, passes through the optical filter 7, is received by the light receiving section 8, and is input to the detection circuit. Thereby, the concentration of the cleaning liquid is measured.

In the first and second embodiments described above, the liquid concentration measuring device is provided on the input side (inflow side of the cleaning liquid) of the cleaning apparatus, but the output side of the cleaning apparatus (discharge of the cleaning liquid). Side) to control the cleaning device by measuring the concentration of the discharged liquid. In this case, the present invention can also be applied to the management of wastewater treatment from a cleaning device.

Further, it is also possible to measure the liquid concentration by providing a measuring conduit in the cleaning tank of the cleaning device and connecting a liquid concentration measuring device thereto.

Further, in each of the above-described embodiments, the cleaning liquid in the cleaning apparatus is measured. However, the liquid concentration is similarly measured in other apparatuses and in the case of any liquid. be able to.

As the bubble adjusting means, other than those used in the above-described embodiments, other defoaming means can be used as long as large air bubbles can be removed.

[0035]

According to the present invention, large bubbles in the measurement liquid can be removed, and the concentration of the liquid can be accurately measured.

[Brief description of the drawings]

FIG. 1 is a perspective view of a measurement cell.

FIG. 2 is a configuration diagram of a measurement cell.

FIG. 3 is a schematic diagram of a liquid concentration measuring device according to the first embodiment of the present invention.

FIG. 4 is a sectional view of a gas-liquid separation tower.

FIG. 5 is a block diagram of a liquid concentration measurement device according to a second embodiment of the present invention.

FIGS. 6A to 6C are explanatory diagrams of a bubble stirring unit.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Measurement cell, 2 ... Measurement part, 11 ... Measurement flow path, 16 ... Gas-liquid separation tower, 17 ... Pressure regulator, 21 ... Bubble stirring part, 22a, 22b ... Partition plate, 30a ... Concentration measuring device, 30b ... Concentration measuring device

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Naoya Hayami 33, Shinisogo-cho, Isogo-ku, Yokohama-shi, Kanagawa Prefecture Inside the Toshiba Production Technology Center (72) Inventor Mitsuru Goto 934-11, Komiyacho, Hachioji-shi, Tokyo (72) Inventor Makoto Kiyo 934-11 Komiyacho, Hachioji-shi, Tokyo Aplix Inc. (72) Inventor Takashi Noguchi 934-11 Komiyacho, Hachioji-shi, Tokyo Aplix Inc. (72) Inventor Hitoshi Okazaki 934-11 Komiyacho, Hachioji-shi, Tokyo F-Terms in Aplix Corporation 2G047 AA01 AD05 BC15 2G057 AA01 AB06 AC01 AD02 AD17 BA05 BB06 DB05 DC07 2G059 AA01 BB04 DD02 DD05 DD12 EE01 JJ02 KK01 NN01

Claims (3)

[Claims] 1. A liquid for flowing a measuring liquid into a measuring cell, irradiating the flowing measuring liquid with light or ultrasonic waves, detecting the transmitted light or ultrasonic waves, and measuring the concentration of the measuring liquid. In a concentration measuring apparatus, a liquid concentration measuring apparatus is provided, wherein a bubble adjusting means for flowing a measuring liquid into the measuring cell and finely pulverizing bubbles mixed in the measuring liquid is provided. 2. The liquid concentration measuring device according to claim 1, wherein said bubble adjusting means is a gas-liquid separation tower connected to a pressure regulator. 3. The liquid concentration measuring device according to claim 1, wherein said bubble adjusting means is a bubble stirring section provided in said conduit.