JP3349636B2 - High frequency cleaning equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a liquid crystal glass substrate,
The present invention relates to an apparatus for high-frequency cleaning an object to be cleaned such as a semiconductor wafer and a magnetic disk.

[0002]

2. Description of the Related Art Conventionally, liquid crystal glass substrates, semiconductor wafers,
To clean an object to be cleaned such as a magnetic disk, a cleaning liquid is contained in a cleaning tank having a vibration plate vibrated by a high-frequency vibrator, and particles on the surface of the object to be cleaned contained in the cleaning liquid by the action of high-frequency sound waves. And so on.

However, in the high-frequency cleaning apparatus having the above-described structure, since the diaphragm is directly mounted in the cleaning tank in which the object to be cleaned is stored, metal ions are eluted from the diaphragm and the diaphragm is fastened to the fastening portion. There was a problem of secondary contamination due to the generation of particles from the packing (gasket) used.

In view of the above, an outer tub containing propagation water, a cleaning tub containing a bottom in the outer tub at a desired distance from the bottom of the outer tub and containing a cleaning liquid therein, A high-frequency device including a vibrating plate disposed at the bottom of the outer tank and configured to apply a high-frequency sound wave to the cleaning liquid through the propagation water, and a vibrator attached to a lower surface of the vibrating plate and vibrated by a high-frequency oscillator; Cleaning devices are known.

However, in a high-frequency cleaning apparatus having a structure in which the outer tank containing the propagation water is disposed so as to cover the bottom of the cleaning tank, the gas component dissolved in the propagation water is converted to the high-frequency wave when the high-frequency sound wave is oscillated. As a result, the high-frequency sound waves cannot be efficiently transmitted to the cleaning water in the cleaning tank. In addition, the gas component becomes bubbles due to the cavitation effect of the sound waves and adheres to the bottom of the cleaning tank, impedes transmission of the sound waves, and reduces the cleaning power for the object stored in the cleaning liquid.

[0006]

DISCLOSURE OF THE INVENTION The present invention relates to an ultrasonic cleaning device capable of efficiently transmitting high-frequency sound waves to cleaning water in a cleaning tank by increasing the transmission (propagation) of high-frequency sound waves in propagation water. It is intended to provide a device.

[0007]

According to the present invention, there is provided a high frequency cleaning apparatus comprising: an outer tank containing propagation water formed of deaerated water;
Bottom spaced a desired distance from the outer tub bottom in the outer tub, and is housed in contact with the propagation water in the outer tub, a cleaning tank pure water is accommodated as a cleaning liquid therein, pure
Is connected to a source of water, it was supplying pure water to the washing tub
A pure water supply pipe fit, is branched from the middle of the pure water supply pipe
A branch pipe has been connected to the branch pipe, through the branch pipe
And degassed water generation means for generating a deaerated water from the supplied pure water is connected to the deaerated water generation means, de in the outer tub
A deaerated water supply pipe for supplying steam as propagation water, and a washing pipe disposed at the bottom of the outer tub and through the propagation water;
To the vibration plate for applying a high-frequency sound waves to the pure water in the tank, and secured to the oscillator to a lower surface of the diaphragm, and characterized by including a high-frequency oscillator for driving the transducer Things.

[0008] The degassed water generating means may adjust the gas dissolved concentration to 1
It is preferable to have a function of controlling the concentration to 0 ppm or less.
The cleaning tank is arranged such that a bottom surface thereof is parallel to the diaphragm.

According to the above-described ultrasonic cleaning apparatus according to the present invention, degassed water as propagation water from the degassed water generating means, ie, pure water from which dissolved gas has been removed, is provided in the outer tub containing the cleaning tub. The high frequency sound wave generated by vibrating the vibrating plate with the vibrator can be efficiently propagated in the propagation water. Further, since it is possible to prevent bubbles from being generated in the propagation water due to the cavitation action of the high-frequency sound waves, it is possible to avoid attenuation of the high-frequency sound waves due to the air bubbles. Therefore, since the high-frequency sound waves from the diaphragm can be efficiently transmitted to the cleaning liquid in the cleaning tank through the propagation water, impurities, particles, and the like on the surface of the object to be cleaned stored in the cleaning liquid can be removed satisfactorily. Precision cleaning can be performed.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A preferred embodiment of the present invention will be described below in detail with reference to FIG. In the outer tank 1, a diaphragm 2 is arranged near the center, and a propagation water 3 made of deaerated water is accommodated in an upper side with the diaphragm 2 as a bottom. The vibrator 4 is attached to the lower surface of the diaphragm 2. High frequency oscillator 5
Is connected to the vibrator 4. The first overflow section 6 is attached around the outer tub 1. The first drain pipe 7 is connected to the bottom of the overflow section 6.

A cleaning tank 10 having a second overflow section 8 at its upper end and containing a cleaning liquid (eg, pure water) 9 is installed in the outer tank 1 such that the bottom thereof is separated from the diaphragm 2 by a desired distance. Have been. Note that the bottom surface of the cleaning tank 10 is disposed so as to be parallel to the vibration plate 2. The second drain tube 11 is connected to the bottom of the second overflow section 8 and has a lower end connected to the first overflow section 6.
Is inserted inside.

A pure water supply pipe 12 for supplying a cleaning liquid, for example, pure water, is arranged such that one end is connected to a supply source of pure water and the other end is located above the cleaning tank 10. Branch pipe 1 branched from the middle of pure water supply pipe 12
Reference numeral 3 is connected to a lower part of a degassed water generation tower 14 which is a degassed water generation means. The degassed water generation tower 14 is loaded with a large number of hollow fibers arranged in the vertical direction, and each of the hollow fibers is made of polytetrofluoroethylene and has a fine hole of 1 μm or less. Vacuum pump 15
Is connected to the degassed water generation tower 14. That is,
The pure water from the branch pipe 13 flows through a plurality of hollow fibers loaded in the degassed water generation tower 14, and the vacuum pump 15 sucks and exhausts gas outside the hollow fibers to remove the pure water. Various gases dissolved in water are discharged and deaerated through the fine holes of the hollow fiber. A deaerated water supply pipe 16 is connected to an upper portion of the deaerated water generation tower 14,
Further, the tip is disposed so as to be located above the outer tub 1.

Next, the operation of the high frequency cleaning apparatus shown in FIG. 1 will be described. First, a plurality of objects to be cleaned (for example, semiconductor wafers) 17 are vertically arranged in a cassette (not shown), and the cassette is set in the cleaning tank 10.
Pure water is supplied into the cleaning tank 10 through a pure water supply pipe 12,
The overflow from the upper end to the second overflow section 8 is performed. The pure water flowing into the second overflow section 8 is discharged to the first overflow section 6 through the second drain-in pipe 11 and further discharged to the outside through the second drain pipe 7. In the supply of pure water to the pure water supply pipe 12, pure water is supplied from the branch pipe 13 into the degassed water generation tower 14. At this time, the pure water flows through the plurality of hollow fibers loaded in the production tower 14, and is dissolved in the pure water by operating the vacuum pump 15 to suck and exhaust the gas outside the hollow fibers. Various gases, such as oxygen, are degassed. The degassed pure water (propagating water) is supplied to the production tower 14
Is supplied into the outer tank 1 through the deaerated water supply pipe 16 from above. Propagation water 3 in the outer tank 1 overflows from near its upper part to the first overflow section 6,
It is discharged outside through the drain tube 7.

As described above, when the propagation water 3 is filled in the outer tank 1 and the pure water (cleaning liquid) 9 is filled in the cleaning tank 10, the high-frequency oscillator 5 is turned on and the outer tank 1 is turned on. When the vibrator 4 attached to the lower surface of the vibrating plate 2 is vibrated, a high-frequency sound wave of, for example, 0.7 to 5 MHz is transmitted from the vibrating plate 2 to the cleaning liquid 9 in the cleaning bath 10 through the propagation water 3 in the outer bath 1. Radiated. In the radiation of the high-frequency sound wave to the propagation water 3, the propagation water 3 is made of degassed pure water,
Since a gas component which is an attenuation factor of the propagation of the high frequency sound wave is removed, the propagating property of the high frequency sound wave in the propagation water 3 can be enhanced. Further, since the propagation water is made of degassed pure water, it is possible to prevent bubbles from being generated in the propagation water due to the cavitation action of high-frequency sound waves. As a result, it is possible to prevent bubbles from adhering to the bottom of the cleaning tank 10 and hindering transmission of ultrasonic waves. Since the high-frequency sound waves can be efficiently transmitted to the cleaning liquid 9 in the cleaning tank 10 through the propagation water 3 in the outer tank 1, the surfaces of the plurality of wafers 17 in the cleaning tank 10 can be cleaned well. The contaminants such as particles that have been removed from the surface of the wafer 17 are overflowed from the overflow section 8 of the cleaning tank 10 together with the cleaning liquid 9, and the second drain pipe 11, the first overflow section 6, and the first pipe drain pipe 7 to the outside.

In particular, pure water is circulated through a plurality of hollow fibers loaded in the production tower 14, and a vacuum pump 15 is operated to suck and exhaust gas outside the hollow fibers, so that the pure water flows into the pure water. When various gases such as dissolved oxygen are discharged and degassed through the fine holes of the hollow fiber, the dissolved concentration of the various gases becomes 1
By controlling to 0 ppm or less, attenuation of high-frequency sound waves due to the generation of bubbles can be effectively prevented. The relationship between the dissolved concentrations of various gases in such propagation water and the sound pressure transmitted to the cleaning liquid in the cleaning tank was determined by the following experiment.

FIG. 2 shows an experimental apparatus for measuring the sound pressure transmitted from the diaphragm to the cleaning liquid in the cleaning tank through the propagation water. Dimension is 300mmW × 500mmD × 50mm
A diaphragm 22 is disposed near the middle of the outer tank 21 of H, and a propagation water 23 is accommodated on an upper side having the diaphragm 22 as a bottom. The vibrator 24 is attached to the lower surface of the diaphragm 22. The high-frequency oscillator 25 includes the vibrator 24
It is connected to the. A cleaning tank 27 having a size of 230 mmW × 380 mmD × 270 mmH, in which a cleaning liquid (for example, pure water) 26 is stored, is installed in the outer tank 21 so that the bottom thereof is parallel to the diaphragm 22 at a desired distance and is parallel thereto. ing. Air supply pipe 2 connected to air pump 28
The lower end of 9 is immersed in the propagation water 23. The lower end of the sound pressure sensor 30 is immersed in the cleaning liquid 26. A converter 31 that outputs sound pressure as a voltage is connected to the sound pressure sensor 30.

In such an experimental apparatus, the dissolved concentrations of various gases are 1 ppm, 3 ppm, 6 ppm, 9 ppm,
12 ppm and 15 ppm of propagation water 23 were added to the outer tank 2.
1 and 7.5 liters of pure water (cleaning liquid) 26 were stored in the cleaning tank 27. In addition,
The dissolved concentration of various gases is 3 ppm, 6 ppm, 9 ppm,
Preparation of the transmission water of 12 ppm and 15 ppm was performed by bubbling air from the air pump 28 through the air supply pipe 29 to the transmission water having a dissolved concentration of various gases of 1 ppm. Thereafter, the high-frequency oscillator 25 is turned on to vibrate the vibrator 24 attached to the lower surface of the vibration plate 22 of the outer tub 21. The sound pressure is radiated to the cleaning liquid 26 in the cleaning liquid 27, the sound pressure is detected by a sound pressure sensor 30 immersed in the cleaning liquid 26, and the sound pressure is output as a voltage by a sound pressure measuring device 31. , Nitrogen, carbon dioxide) and the sound pressure (voltage) were determined. The results are shown in Table 1 below.

Table 1 Dissolved concentrations of various gases (ppm) 13 5 9 12 15 Output from measuring instrument (mV) 2.5 2.5 2.4 1.75 0.45 0.6 As is clear from Table 1, the dissolved concentrations of various gases in the propagation water It can be seen that when the content is set to 10 ppm or less, high-frequency sound waves from the diaphragm can be favorably transmitted to the cleaning liquid in the cleaning tank through the propagation water.

Therefore, according to the ultrasonic cleaning apparatus of the present invention, the vibrating plate 2 is vibrated so that high-frequency sound waves are radiated to the propagation water 3 made of degassed pure water in the outer tub 1, whereby the propagation is achieved. Since the propagating property of high-frequency sound waves in the water 3 can be enhanced, it is possible to efficiently transmit the cleaning liquid 10 to efficiently remove impurities, particles, and the like on the surface of the wafer 18 accommodated therein and perform precision cleaning. Can be.

Further, the cleaning liquid overflowing from the cleaning tank 10 is supplied to the second overflow section 8, the second drain pipe 11, the first overflow section 6 and the first drain pipe 7.
The cleaning liquid can be prevented from being mixed into the propagation water 3 in the outer tank 1 by discharging through
The high-frequency sound wave from the diaphragm 2 is efficiently transmitted to the cleaning tank 1.
0 can be propagated to the cleaning solution.

Further, the degassed water generated in the degassed water generation tower 14 is always supplied into the outer tank 1 through the degassed water supply pipe 16 and is supplied from the first overflow section 6 and the first drain pipe 7. If the water is discharged, the propagation water 3
Since it is possible to prevent various gases such as oxygen from the atmosphere from dissolving in the propagation water by staying in the inside, it is possible to maintain high propagation of high-frequency sound waves during the cleaning process.

Furthermore, since bubbles can be prevented from being generated when high-frequency sound waves are applied to the propagating water, the bottom of the cleaning tank 10 can be arranged in parallel with the diaphragm 2 without tilting the bottom surface for the purpose of removing bubbles.

In the above-described embodiment, the degassed water generating means is constituted by the degassed water generating tower containing a plurality of hollow fibers and the vacuum pump. However, another form of the degassed water generating means may be used. .

[0024]

As described above in detail, according to the present invention, the high-frequency sound wave is efficiently transmitted to the cleaning water in the cleaning tank by increasing the propagation (transmittance) of the high-frequency sound wave in the transmitting water. It can remove impurities, particles, etc. on the surface of the object to be cleaned in the cleaning tank well and perform precision cleaning, and thus can be effectively applied to cleaning processes such as manufacturing of semiconductor devices, liquid crystal display devices and magnetic disks. A possible high-frequency cleaning device can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a high frequency cleaning device according to the present invention.

FIG. 2 is a schematic sectional view showing an experimental apparatus for measuring a sound pressure transmitted from a diaphragm to a cleaning liquid in a cleaning tank through propagation water.

[Explanation of symbols]

 1, 21 ... outer tank, 2, 22 ... diaphragm 3, 23 ... propagation water, 5, 25 ... high frequency oscillator, 9, 26 ... washing liquid, 10, 27 ... washing tank, 14 ... degassed water generation tower, 17 ... Object to be cleaned (semiconductor wafer).

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Teruyuki Kobayashi 2426-1, Michikamiguchi, Nosu-cho, Yasu-cho, Yasu-gun, Shiga Prefecture Yasu Office, Dainippon Screen Mfg. Co., Ltd. (72) Inventor Takashi Ueno Yasu, Shiga Prefecture 2426-1, Minogami, Minogami, Kuchinogawara, Gunnosu-cho, Japan Yasu office of Dainippon Screen Mfg. Co., Ltd. (56) References JP-A-8-155409 (JP, A) Jpn. (58) Field surveyed (Int. Cl. ⁷ , DB name) B08B 3/12 B01D 19/00 101 B08B 3/10

Claims (2)

(57) [Claims] 1. An outer tank in which propagation water made of degassed water is stored, and a bottom in the outer tank is separated from the bottom of the outer tank by a desired distance, and is in contact with the propagation water in the outer tank. stored, and supplies a cleaning tank pure water is accommodated as the cleaning liquid is connected to a source of pure water, pure water to the washing tub inside
A pure water supply pipe for the branch pipe which is branched from the middle of the pure water supply pipe is connected to the branch pipe, which is fed through the branch pipe
And degassed water generation means for generating a deaerated water from the pure water, coupled to said degassed water generating means, and degassed water to the outer tub Den
A deaerated water supply pipe for supplying as seeding water, and a washing pipe which is disposed at a bottom of the outer tank and which is provided with the propagating water.
And wherein a diaphragm for applying high frequency waves to the pure water in Kiyoshiso, and attached to the vibrator to the lower surface of the vibration plate, by comprising a high frequency oscillator for driving the transducer High frequency cleaning equipment. 2. The high frequency cleaning apparatus according to claim 1, wherein said degassed water generating means has a function of controlling a gas dissolved concentration to 10 ppm or less.