JPH09243419A - Sucking apparatus for liquid sample - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable continuous sucking of liquid sample and prevent leakage and contamination by supplying working fluid of a predetermined pressure to an aspirator connected to an exhaust port of a measuring apparatus and adjusting a flow rate of the liquid sample flowing into the measuring apparatus. SOLUTION: A suction port of an aspirator 10 is connected via a pipe 9 to an exhaust port of a particle detector 7 for supplying working fluid of a constant pressure to the aspirator 10 by a working fluid supply source 15, so that, when the working fluid is exhausted through the aspirator 10 from the pipe 9 to an overflow reservoir 3, fluid existing inside is also exhausted together with the working fluid. Therefore, an internal space of the aspirator 10 is reduced in pressure, so that detergent (liquid sample) 2 in a cleaning tank 1 is led through the pipe 9 to the detector 7, and further, sucked into the aspirator 10, thereby enabling continuous suction as long as the working fluid is supplied 15. In addition, since the aspirator 10 is free from mechanical activation or sliding elements, it may not be suffered from deterioration due to wearing or leakage, contamination of the liquid sample by worn powder or gas lock.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a suction device for sucking a liquid sample open to the atmosphere into a measuring device for measuring particle size distribution and the like, and particularly measuring the cleanliness of a liquid used in a semiconductor manufacturing process. The present invention relates to a liquid sample suction device used at that time.

[0002]

2. Description of the Related Art In order to improve the yield in the production of semiconductors, it is important to keep the concentration of particles in the liquid used low and keep the liquid clean. Therefore, a particle measuring device is used to confirm the cleanliness of the liquid. In the semiconductor manufacturing process, a wafer cleaning process is particularly important. In this step, the wafer is immersed in the cleaning liquid filled in the cleaning tank to wash off the contaminant particles adhering to the wafer surface. Normally, the cleaning tank is open to the atmosphere to facilitate the loading and unloading of wafers. Therefore, the pressure of the liquid in the cleaning tank is maintained at atmospheric pressure, and a suction device as a decompression unit is required to introduce this liquid to the particle measuring device.

Although various types of pumps can be used as the suction device, there is a constraint that there must be no pulsation in order to measure particles in a liquid. This is because if there is pulsation, the particles move in the particle measuring device while repeating the reciprocating motion along the flow direction of the liquid, and the particle measuring device detects one particle as a plurality of particles. .

Conventionally, a syringe pump or a gear pump has been used as a suction device without pulsation. The syringe pump is a system that depressurizes the inside of the cylinder by moving a piston inside the cylinder. On the other hand, the gear pump is a system in which two gears, which are usually arranged in the casing, rotate while meshing with each other to reduce the pressure between the casing and the gears.

[0005]

In the conventional suction device, since a syringe pump or a gear pump having a portion that slides by mechanical movement is used, the sliding portion deteriorates due to wear and liquid leakage occurs. I was afraid. Further, since the sample liquid is in contact with the sliding portion, particles generated by sliding wear contaminate the sample liquid. Further, in an environment contaminated with corrosive vapor such as hydrochloric acid or hydrogen fluoride, metal mechanical parts and electric parts may be corroded.

Further, in the case of the syringe pump, the operation is intermittent and it is not suitable for continuous measurement by continuous suction of the sample liquid. On the other hand, in the case of the gear pump, the gas generated in the liquid stays between the gear and the casing, and even if the gear rotates, the gas lock phenomenon occurs in which the liquid is not transported but idle. This gas lock phenomenon is remarkable for a liquid that is easily vaporized, and has been generated when sucking hydrogen peroxide solution or ammonia solution used for manufacturing semiconductors.

Also, in the liquid used in the semiconductor industry, there is a 70-fold change in the viscous resistance from acetone (relatively low viscosity) (about 0.3 cP) to concentrated sulfuric acid (relatively high viscosity) (about 20 cP). Can get up Therefore, it is sometimes required for the liquid sample suction device to cope with this change. However, it is not possible to deal with this change in viscous resistance only with a pressure regulator having an adjustment range of about 10 times. Therefore, in this case, in addition to the pressure regulator, a further flow rate adjusting means is required in the suction device.

The present invention has been made in view of the above problems of the prior art. The object of the present invention is to prevent the sample liquid from leaking or being contaminated due to wear and to allow continuous suction. An object of the present invention is to provide a liquid sample suction device in which the gas lock phenomenon does not occur.

[0009]

In order to solve the above problems, the invention of claim 1 is a suction device for sucking the liquid sample into a measuring device for measuring the particle size distribution of the liquid sample. An aspirator having a suction port, a working fluid supply port, and a working fluid discharge port is provided, the suction port is connected to the discharge port of the measuring device, and the working fluid is supplied from the supply port at a predetermined pressure and discharged from the discharge port. By doing so, the flow rate of the liquid sample flowing into the measuring device is adjusted.

According to a second aspect of the present invention, there is provided a suction device for sucking the liquid sample into a measuring device for measuring the particle size distribution of the liquid sample, wherein the suction port for the liquid sample and the supply and discharge ports for the working fluid are provided. With the aspirator having, a flow rate adjusting means is provided between the discharge port of the measuring device and the suction port of the aspirator, and the working fluid supplied from the supply port by the flow rate adjusting device flows into the measuring device. The flow rate of the liquid sample is adjusted.

Further, the flow rate adjusting means in the invention of claim 2 may be a needle valve or an orifice.

[0012]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Here, FIG. 1 is an explanatory view of a semiconductor wafer cleaning apparatus to which the liquid sample suction device according to the invention of claim 1 is applied, FIG. 2 is a sectional view of an aspirator, and FIG. 3 is a liquid sample according to the invention of claim 2. 7 is an explanatory view of a semiconductor wafer cleaning apparatus to which the suction device of FIG. 4 is applied, FIG. 4 is a sectional view showing a needle valve installation state, FIG. 5 is a perspective view of an orifice, FIG. 6 is a sectional view showing an orifice installation state, and FIG.
FIG. 4 is a cross-sectional view showing a state where an orifice is installed in an aspirator.

As shown in FIG. 1, a semiconductor wafer cleaning apparatus to which the liquid sample suction device according to the first aspect of the invention is applied is a cleaning tank 1 at atmospheric pressure opened for cleaning a wafer by immersing it in a cleaning liquid 2. An overflow tank 3 for storing the cleaning liquid 2 overflowing from the cleaning tank 1, a circulation pump 4 for sending the cleaning liquid 2 accumulated in the overflow tank 3 to the cleaning tank 1 again, and a filter 5 for purifying the cleaning liquid 2 accumulated in the overflow tank 3. When,
The overflow tank 3 and the cleaning tank 1 are composed of a circulation pipe 6 which connects the circulation pump 4 and a filter 5 to each other.

Further, the semiconductor wafer cleaning apparatus supplies a particle detecting device 7 which is a measuring device for inspecting the degree of contamination of the cleaning liquid 2, and the cleaning liquid 2 as a liquid sample at a predetermined flow rate to the particle detecting device 7. The suction device 8 is installed. The cleaning tank 1 is provided at the supply port of the particle detecting device 7.
A pipe 9 is connected to supply the cleaning liquid 2 filled in the particle detector 7 to the particle detector 7.

As the cleaning liquid 2, pure water, hydrofluoric acid,
Hydrochloric acid, sulfuric acid, nitric acid, etc. are used. As the circulation pump 4, for example, a diaphragm pump or the like is used. As the measuring device, in addition to the particle detecting device 7, a fluid analyzing device,
For example, an ion concentration meter (only in the case of pure water) or an organic matter concentration meter can be applied.

The suction device 8 includes an aspirator (water flow pump) 10, a pressure regulator 11 for adjusting the working fluid supplied to the aspirator 10 to a predetermined pressure, a pressure gauge 12 for displaying the pressure of the working fluid, and a working fluid It is composed of a check valve 13 for preventing backflow and a filter 14 for filtering particles existing in the working fluid to prevent contamination of the cleaning liquid 2.
Reference numeral 15 is a working fluid supply source that supplies the working fluid to the aspirator 10 at a predetermined pressure.

As a working fluid, tap water is generally used in a general aspirator. However, since various types of liquid samples are used in the semiconductor industry, when tap water is used as a working fluid, a mixture of tap water and a liquid sample may be discharged, and its treatment may be troublesome. Therefore, a gas such as air or nitrogen gas is used as the working fluid.

The aspirator 10 is, as shown in FIG.
Hollow main body 10a and cleaning liquid 2 protruding from the main body 10a
A suction pipe 10b, a working fluid supply pipe 10c fitted to the center of the inside of the main body 10a, and a discharge pipe 10d for a mixed fluid of the cleaning liquid 2 and the working fluid protruding from the main body 10a.
The suction pipe 10b has a suction port 10e, the supply pipe 10c has a supply port 10f, and the discharge pipe 10d has a discharge port 10g. The aspirator 10 is a PTFE (Polytetrafluor) with good chemical resistance in order to cope with corrosive liquid samples.
It is preferably composed of a fluororesin such as ethylene.

The suction port 10e of the suction pipe 10b is connected to the discharge port of the particle detecting device 7 via a pipe 9, and the supply pipe 10b.
The supply port 10f of c is connected to the outlet side of the filter 14 via the pipe 9, and the discharge port 10g of the discharge pipe 10d is connected to the pipe 9
It faces above the overflow tank 3.

The operation of the semiconductor wafer cleaning apparatus to which the liquid sample suction apparatus according to the first aspect of the present invention having the above-described structure is applied will be described. First, the working fluid adjusted by the working fluid supply source 15 to have a constant pressure above a certain level is supplied to the supply port 10f of the aspirator 10. Then, the working fluid passes through the supply pipe 10c and is discharged toward the discharge pipe 10d in the main body 10a. At this time, the main body 10a
The fluid existing inside the chamber is also drawn by the flow of the working fluid and discharged together with the working fluid.

By discharging the working fluid together with the fluid existing inside the main body 10a, the internal space of the main body 10a is depressurized, and the cleaning liquid 2 as a liquid sample filled in the cleaning tank 1 flows through the pipe 9. It is guided to the particle detecting device 7 through the pipe 9 and further sucked into the main body 10a through the pipe 9.
Since the aspirator 10 has a simple structure in which the tubes 10b, 10c, 10d are combined, continuous suction is possible as long as the working fluid is supplied. Also, the aspirator 10
Does not have elements that mechanically operate or slide, so that deterioration due to wear, leakage, contamination of the liquid sample by wear powder, gas lock, etc. do not occur.

At this time, the flow rate of the cleaning liquid 2 supplied to the particle detecting device 7 is controlled by the pressure adjuster 11.
Can be adjusted to the desired flow rate. However,
When the working fluid supply source 15 supplies the working fluid at a pressure at which the flow rate of the cleaning liquid 2 supplied to the particle detecting device 7 becomes a desired flow rate, the pressure regulator 11 is not required.

Further, due to the action of the check valve 13, the supply port 1
It is possible to prevent the cleaning liquid 2 from flowing back to the working fluid supply source 15 from 0f. The function of the check valve 13 is that the pressure regulator 11 and the working fluid supply source 1 are applied when a corrosive liquid is targeted.
It is effective in protecting 5 etc. from corrosion. Further, since the filter 14 filters the particles in the working fluid and supplies the working fluid to the aspirator 10, the cleaning liquid 2 can be prevented from being contaminated. The function of the filter 14 is effective when the cleaning liquid 2 is recycled and reused.

Next, the cleaning liquid 2 continuously sucked into the main body 10a is discharged together with the working fluid from the discharge port 10g to the pipe 9
Through to the overflow tank 3. The cleaning liquid 2 accumulated in the overflow tank 3 is circulated by the circulation pump 4 to the circulation pipe 6
After being purified by the filter 5, it returns to the cleaning tank 1.
In the cleaning tank 1, the cleaning liquid 2 always overflows.

As shown in FIG. 3, a semiconductor wafer cleaning apparatus to which the liquid sample suction device according to the second aspect of the present invention is applied is a cleaning tank 1 in which a wafer is immersed in a cleaning liquid 2 for cleaning.
An overflow tank 3 for storing the cleaning liquid 2 overflowing from the cleaning tank 1, a circulation pump 4 for sending the cleaning liquid 2 accumulated in the overflow tank 3 to the cleaning tank 1 again, and a filter for purifying the cleaning liquid 2 accumulated in the overflow tank 3. 5, a circulation pipe 6 that connects the overflow tank 3 and the cleaning tank 1 to each other through a circulation pump 4 and a filter 5.

Further, the semiconductor wafer cleaning device supplies a particle detecting device 7 which is a measuring device for inspecting the degree of contamination of the cleaning liquid 2, and the cleaning liquid 2 as a liquid sample at a predetermined flow rate to the particle detecting device 7. A suction device 8 for
Flow rate adjusting means 20 is provided between the particle detecting device 7 and the suction device 8.
Is provided. Therefore, it is the same as the semiconductor wafer cleaning apparatus shown in FIG. 1 except that the flow rate adjusting means 20 is provided.

The flow rate adjusting means 20 plays a role of adding viscous resistance to the fluid and uses a needle valve 21 shown in FIG. 4 or an orifice 22 shown in FIG. As shown in FIG. 4, when the knob 21a of the needle valve 21 is rotated, the tapered valve element 21c moves up and down by the action of the screw 21b. By this vertical movement,
The interval of the gap formed by the valve seat 21d and the valve body 21c changes. By changing the interval, the viscous resistance applied to the cleaning liquid 2 can be changed to adjust the flow rate of the cleaning liquid 2 supplied to the particle detecting device 7. The needle valve 21 is connected to the pipe 9 via a joint 23. Reference numeral 24 is a housing panel of the suction device 8 to which the needle valve 21 is attached.

As shown in FIG. 5, the orifice 22 is made of a disk-shaped solid 22a, and a circular fine hole 22b is formed at the center of the solid 22a. The shape of the orifice 22 is not limited to the disk shape, and may be a rectangular parallelepiped or the like. Further, the shape of the pores 22b is not limited to a circle and may be a quadrangle. The orifice 22 is preferably made of a fluororesin such as PTFE (Polytetraethylene) having good chemical resistance in order to cope with a corrosive liquid sample. Further, the orifice 22
It is also possible to use ceramics or sapphire, which has good chemical resistance and a small coefficient of thermal expansion, as the material.

In FIG. 6, the orifice 22 is used for the particle detecting device 7.
Showing the state of being mounted between the suction device 8 and the suction device 8.
2 is disposed between the FMC joint 25 and the BMC joint 26 mounted on the housing panel 24. The FMC joint 25 and the BMC joint 26 are connected to the pipe 9 via the joint 23, respectively.
It is connected to the. Orifice 22 is FMC joint 25
It can be easily replaced by rotating and removing. By exchanging the orifices 22 with different diameters of the fine holes 22b, the viscous resistance applied to the cleaning liquid 2 can be changed to adjust the flow rate of the cleaning liquid 2 supplied to the particle detecting device 7.

FIG. 7 shows the orifice 22 with the aspirator 1
0 is directly attached to the suction port 10e, the female screw 27 is formed on the inner peripheral surface of the suction port 10e, the orifice 22 is fitted to the inner circumferential surface of the suction port 10e, and then the MC joint 28 is screwed onto the female screw 27. The orifice 22 is fixed by combining them. MC joint 2
8 is connected to the pipe 9 via a joint 23. The orifice 22 can be easily replaced by rotating and removing the MC joint 28. By changing the orifice 22 having a different diameter of the fine hole 22b, the viscous resistance applied to the cleaning liquid 2 is changed to supply the cleaning liquid 2 to the particle detecting device 7.
The flow rate can be adjusted.

The operation of the semiconductor wafer cleaning apparatus to which the liquid sample suction apparatus according to the second aspect of the present invention having the above-described structure is applied will be described. First, the working fluid adjusted by the working fluid supply source 15 to have a constant pressure above a certain level is supplied to the supply port 10f of the aspirator 10. Then, the working fluid passes through the supply pipe 10c and is discharged toward the discharge pipe 10d in the main body 10a. At this time, the main body 10a
The fluid existing inside the chamber is also drawn by the flow of the working fluid and discharged together with the working fluid.

By discharging the working fluid together with the fluid existing inside the main body 10a, the internal space of the main body 10a is depressurized, and the cleaning liquid 2 as a liquid sample filled in the cleaning tank 1 flows through the pipe 9. It is guided to the particle detecting device 7 through the pipe 9 and further sucked into the main body 10a through the pipe 9.
Since the aspirator 10 has a simple structure in which the tubes 10b, 10c, 10d are combined, continuous suction is possible as long as the working fluid is supplied. Also, the aspirator 10
Does not have elements that mechanically operate or slide, so that deterioration due to wear, leakage, contamination of the liquid sample by wear powder, gas lock, etc. do not occur.

At this time, the flow rate of the cleaning liquid 2 supplied to the particle detecting device 7 is set to the needle valve 21 or the orifice 22.
Due to viscous resistance. Even if the viscosity of the cleaning liquid 2 is 70 times different, in the case of the needle valve 21, the knob 21a is rotated to rotate the valve seat 21d and the valve body 2
By adjusting the spacing of the gap formed by 1c, and in the case of the orifice 22, by replacing the orifice 22 with an orifice 22 having a different diameter of the fine hole 22b, the problem of flow rate adjustment that is difficult only with a pressure regulator is addressed. it can.

Further, due to the action of the check valve 13, the supply port 1
It is possible to prevent the cleaning liquid 2 from flowing back to the working fluid supply source 15 from 0f. The function of the check valve 13 is that the pressure regulator 11 and the working fluid supply source 1 are applied when a corrosive liquid is targeted.
It is effective in protecting 5 etc. from corrosion. Further, since the filter 14 filters the particles in the working fluid and supplies the working fluid to the aspirator 10, the cleaning liquid 2 can be prevented from being contaminated. The function of the filter 14 is effective when the cleaning liquid 2 is recycled and reused.

Next, the cleaning liquid 2 continuously sucked into the main body 10a is discharged from the discharge port 10g together with the working fluid through the pipe 9
Through to the overflow tank 3. The cleaning liquid 2 accumulated in the overflow tank 3 is circulated by the circulation pump 4 to the circulation pipe 6
After being purified by the filter 5, it returns to the cleaning tank 1.
In the cleaning tank 1, the cleaning liquid 2 always overflows.

[0036]

As described above, according to the present invention, since the suction device is composed of an aspirator, there is no leakage or contamination due to wear, continuous suction is possible, gas lock does not occur, and liquids of different viscosity are used. Can easily handle samples.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a semiconductor wafer cleaning device to which a liquid sample suction device according to the first aspect of the invention is applied.

FIG. 2 is a sectional view of an aspirator.

FIG. 3 is an explanatory view of a semiconductor wafer cleaning device to which the liquid sample suction device according to the second aspect of the invention is applied.

FIG. 4 is a cross-sectional view showing an installed state of a needle valve.

FIG. 5 is a perspective view of an orifice

FIG. 6 is a cross-sectional view showing an installed state of an orifice.

FIG. 7 is a cross-sectional view showing how the orifice is installed in the aspirator.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Cleaning tank, 2 ... Cleaning liquid (liquid sample), 3 ... Overflow tank, 4 ... Circulation pump, 5, 14 ... Filter, 6 ... Circulation pipe, 7 ... Particle detection device (measurement device), 8 ... Suction device, 10 ... Aspirator, 10a ... Main body, 10b ... Suction pipe, 10c ... Supply pipe, 10d ... Exhaust pipe, 10e ... Suction port, 10f ... Supply port, 10g ... Exhaust port, 11 ... Pressure regulator, 13 ... Check valve, 15 ... Working fluid supply source, 20 ... Flow rate adjusting means, 21 ... Needle valve, 22 ... Orifice,
22b ... Pores.

Claims (4)

[Claims] 1. A suction device for sucking the liquid sample into a measuring device for measuring the particle size distribution of the liquid sample, the aspirator having a suction port for the liquid sample, a supply port and a discharge port for a working fluid, The flow rate of the liquid sample flowing into the measuring device is adjusted by connecting the suction port to the discharge port of the measuring device, supplying the working fluid at a predetermined pressure from the supply port, and discharging the working fluid from the discharge port. A liquid sample suction device, characterized in that: 2. A suction device for sucking the liquid sample into a measuring device for measuring the particle size distribution of the liquid sample, the device including an aspirator having a suction port for the liquid sample and a supply port and a discharge port for a working fluid. A flow rate adjusting means is provided between the discharge port of the measuring device and the suction port of the aspirator, and the flow rate of the liquid sample flowing into the measuring device by the working fluid supplied from the supply port by the flow rate adjusting device. And a liquid sample suction device. 3. The liquid sample suction device according to claim 2, wherein the flow rate adjusting means is a needle valve. 4. The liquid sample suction device according to claim 2, wherein the flow rate adjusting means is an orifice.