JP2007326088A - Ultrasonic cleaning system and ultrasonic cleaning method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an ultrasonic cleaning system and an ultrasonic cleaning method capable of performing a cleaning high in cleaning effect and cleaning efficiency by controlling the amount of bubbles generated in a cleaning liquid. <P>SOLUTION: The ultrasonic cleaning system which cleans articles to be cleaned by propagating ultrasonic waves to the cleaning liquid, is characterized by being provided with a cleaning vessel for storing the cleaning liquid and housing the articles to be cleaned to clean them; an ultrasonic oscillation means for generating the ultrasonic waves; a measuring means for measuring the amount of bubbles generated in the cleaning vessel; and a control means for controlling the oscillation output of the ultrasonic oscillation means based on the result of measuring the amount of the bubbles. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an ultrasonic cleaning system and an ultrasonic cleaning method, and specifically, an ultrasonic cleaning system and an ultrasonic cleaning method that are suitable for ultrasonic cleaning of a solid that is an object to be cleaned in a liquid. About.

  In the manufacturing process of electronic parts, precision machine parts, optical parts, etc., it may be required to clean the surface extremely. In particular, the surface of a substrate used for a liquid crystal display device, a semiconductor device, or the like is required to remove as much deposit as possible.

  An ultrasonic cleaning method is generally known as a method for cleaning a substrate surface or the like that requires such a high cleanliness. In this cleaning method, a cleaning tank containing an object to be cleaned is filled with a cleaning liquid, ultrasonic waves are radiated from the ultrasonic vibrator attached to the bottom or side surface of the cleaning tank, and ultrasonic vibration is applied to the cleaning liquid. In this way, cleaning is performed. In this method, the cavitation generated inside the cleaning liquid due to the change in the sound pressure of the ultrasonic wave in the cleaning liquid (the movement of the liquid causes the liquid to locally become a low pressure, generating bubbles, and the bubbles are crushed by pressure. The deposits on the surface of the object to be cleaned placed in the cleaning liquid are removed by using (destructive). For this reason, in the cleaning using cavitation, bubbles generated in the cleaning liquid greatly affect the cleaning of the surface of the object to be cleaned.

  Here, a technique is disclosed in which the amount of bubbles generated in the ultrasonic wave propagation liquid during ultrasonic irradiation is measured, and the ultrasonic output is controlled according to the result (see Patent Document 1).

However, this technique measures the amount of bubbles generated in the ultrasonic wave propagation liquid, and does not measure the amount of bubbles generated in the cleaning liquid in which the object to be cleaned is placed. For this reason, there has been a problem in increasing the cleaning effect by controlling the amount of bubbles generated in the cleaning liquid.
JP 2001-9395 A

  The present invention provides an ultrasonic cleaning system and an ultrasonic cleaning method capable of performing cleaning with high cleaning effect and cleaning efficiency by controlling the amount of bubbles generated in the cleaning liquid.

  According to one aspect of the present invention, an ultrasonic cleaning system that propagates ultrasonic waves to a cleaning liquid to clean an object to be cleaned, the cleaning tank storing the cleaning liquid and containing and cleaning the object to be cleaned; Ultrasonic oscillation means for generating the ultrasonic waves, measurement means for measuring the amount of bubbles generated in the cleaning tank, and control for controlling the oscillation output of the ultrasonic oscillation means based on the measurement result of the amount of bubbles Means for providing an ultrasonic cleaning system.

  According to another aspect of the present invention, there is provided an ultrasonic cleaning method for cleaning an object to be cleaned by propagating ultrasonic waves generated by ultrasonic oscillating means to a cleaning liquid, wherein the object to be cleaned is accommodated and cleaned. There is provided an ultrasonic cleaning method characterized by measuring the amount of bubbles generated in the cleaning tank and controlling the oscillation output of the ultrasonic oscillation means based on the result.

  According to the present invention, it is possible to provide an ultrasonic cleaning system and an ultrasonic cleaning method that can perform cleaning with high cleaning effect and cleaning efficiency by controlling the amount of bubbles generated in the cleaning liquid.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram showing an ultrasonic cleaning system according to an embodiment of the present invention.

  The ultrasonic cleaning system 1 has a direct tank 3 that is open at the top and can store a cleaning liquid 2 such as pure water or a chemical liquid. In addition, a holder (not shown) for holding the object to be cleaned W is provided directly inside the tank 3. An indirect tank 4 is provided at the bottom of the direct tank 3 so as to cover the entire bottom, and an ultrasonic oscillating means 5 is fixed to the bottom of the indirect tank 4. The indirect tank 4 is filled with an ultrasonic propagation liquid such as water, and the ultrasonic wave oscillated by the ultrasonic wave oscillating means 5 propagates directly to the cleaning liquid 2 through the bottom of the tank 3. The indirect tank 4 is not always necessary, and the ultrasonic oscillating means 5 may be directly fixed to the bottom of the tank 3. An oscillation power source 6 capable of supplying high frequency power of about 1 megahertz is electrically connected to the ultrasonic oscillating means 5. Control means 15 is electrically connected to the oscillation power source 6 so that the oscillation output of the ultrasonic oscillation means 5 can be controlled.

  A pipe line 8 provided with an on-off valve 7 is connected to the indirect tank 4 so that the ultrasonic wave propagation liquid can be supplied or discharged. A pipe line 10 provided with an on-off valve 9 is connected near the bottom of the tank 3 directly, and a cleaning liquid supply means (not shown) is connected to the other end of the pipe line 10. A tub 11 for receiving the overflowed cleaning liquid 2 is provided directly on the periphery of the opening of the tank 3, and a drain pipe 12 is connected to the bottom of the tub 11. A cleaning liquid recovery means (not shown) is connected to the other end of the drain pipe 12.

  A sampling tube 13 for extracting the cleaning liquid 2 is provided so as to be directly inserted into the inside through the opening of the tank 3. A bubble amount measuring means 14 is connected to the other end of the sampling tube 13. The bubble amount measuring means 14 also has a function of sucking the cleaning liquid 2 directly from the tank 3 through the sampling pipe 13, and the cleaning liquid 2 that has been measured is discharged to the basket 11 through the discharge pipe 21. Control means 15 is electrically connected to the bubble amount measuring means 14 so that measurement data can be transmitted and received. The control unit 15 has a function of controlling the oscillation output of the ultrasonic oscillation unit 5 based on the measurement data sent from the bubble amount measurement unit 14.

Hereinafter, before describing the operation of the ultrasonic cleaning system of the present embodiment, the relationship between bubbles generated by cavitation and the cleaning effect will be described first.
FIG. 2 is an enlarged schematic view of the vicinity of the interface of the object to be cleaned held in the cleaning liquid.

  When cavitation occurs inside the cleaning liquid 2 due to the ultrasonic waves oscillated from the ultrasonic oscillating means, some of the bubbles 20 grow as spherical uniform nuclei while repeating expansion and contraction. On the other hand, some of the other bubbles 22a and 22b are asymmetric and collapse without growing. In the figure, 22a indicates crushing in the vicinity of the interface of the object to be cleaned W, and 22b indicates crushing in a place away from the interface of the object to be cleaned W. When such bubble collapse occurs, a pressure wave is generated when the bubble disappears, and the deposit on the surface of the workpiece W is removed by the pressure wave.

  As a result of the study, the present inventor has found that the cleaning effect can be known by measuring the amount of bubbles 22a and 22b to be crushed. When the bubbles 22a and 22b are crushed, the cleaning liquid 2 is thermally decomposed to generate hydrogen radicals, oxygen radicals, and the like, so that the amount of bubbles 22a and 22b to be crushed can be known by measuring the amount of radicals generated. And gained knowledge.

  Here, since the lifetime of the radical is about several microseconds, it is difficult to measure this as it is. Therefore, a radical trapping agent (for example, 5,5-Dimethyl-1-pyrroline N-oxide: DMPO) was added to stabilize the radical and measure it. If radicals are stabilized by a radical trapping agent, the lifetime will be several hours. Therefore, if the cleaning liquid 2 containing stable radicals is extracted and analyzed by an ESR (Electron Spin Resonance) spectrometer, the amount of radicals can be measured. Can do. In addition, it is desirable to perform the measurement in a state where there is no object to be cleaned because of adding a radical trapping agent.

  By doing so, it is possible to know the amount of bubbles 22a and 22b to be crushed from the amount of radicals generated, and to know the cleaning effect at that time. In addition, since the amount of radicals generated behaves depending on the output of the ultrasonic oscillating means, the amount of radicals generated (the amount of bubbles to be crushed) can be controlled by controlling the output of the ultrasonic oscillating means. The cleaning effect at the time can also be controlled.

  As a result of further studies, the present inventor has obtained the knowledge that the amount of bubbles 22a and 22b that can be more easily crushed can be measured and the cleaning effect at that time can be known.

  The above-described bubbles 20 that grow as uniform nuclei (bubbles that do not collapse) do not generate pressure waves and thus do not directly contribute to the cleaning effect. However, the inventors have found that there is a correlation between the amount of bubbles 20 growing as uniform nuclei and the amount of bubbles 22a and 22b to be crushed. That is, it has been found that as the amount of bubbles 22a and 22b to be crushed increases, the amount of bubbles 20 that grow as uniform nuclei also increases in proportion thereto. Thus, the inventors have found that the amount of bubbles 22a and 22b to be crushed can be determined by measuring the amount of bubbles 20 that grow as uniform nuclei that can be easily measured. Since the amount of bubbles 20 growing as uniform nuclei can be measured by a laser scattering method or an ultrasonic method, which will be described later, when combined with the measurement of the radical amount described above, the amount of bubbles 20 growing as uniform nuclei and the crushing bubbles 22a, The correlation between the amount of 22b will be found. Based on this correlation, the amount of bubbles 22a and 22b to be crushed can be known from the measured amount of bubbles 20 growing as uniform nuclei, and the cleaning effect at that time can also be known.

  Also, if the amount of bubbles 20 that grow as uniform nuclei is controlled as an index, the cleaning effect at that time can be controlled.

  FIG. 3 is a graph for illustrating the relationship between the amount of bubbles 20 generated as uniform nuclei (the number of bubbles) and the output of the ultrasonic oscillation means. The vertical axis represents the number of detected bubbles per 10 milliliters, and the horizontal axis represents the output of the ultrasonic oscillation means. Here, since the bubbles 20 that grow as uniform nuclei are spherical and have a diameter of 0.3 μm to 0.5 μm, the amount of bubbles generated is measured as the number of bubbles. As the cleaning liquid, nitrogen water having a dissolved amount of nitrogen of 14 PPM (Parts Per Million) was used.

  As can be seen from FIG. 3, since the number of detected bubbles shows a behavior depending on the output of the ultrasonic oscillating means, the amount of bubbles 20 generated (number of bubbles) can be controlled by controlling the output of the ultrasonic oscillating means. And the cleaning effect at that time can be controlled. Further, since only the amount of the bubbles 20 that grow as uniform nuclei is measured, it is not necessary to add a radical trapping agent, and the measurement can be performed during the cleaning of the object to be cleaned. Therefore, cleaning under more precise cleaning conditions is possible.

  As described above, the generation amount (number of bubbles) of the bubbles 20 can be controlled, and the cleaning effect at that time can also be controlled. ) And the cleaning effect at that time, it was found that there is an optimum range.

  FIG. 4 is a graph for illustrating the relationship between the generation amount (the number of bubbles) of bubbles 20 growing as uniform nuclei and the removal rate of attached substances. The vertical axis represents the deposit removal rate, and the horizontal axis represents the number of bubbles detected per 10 milliliters. The detection of the number of bubbles and the cleaning liquid were the same as described above. The circular figure shown below the graph is for visually representing the degree of removal of deposits on the wafer used as a sample.

  The circular figure also shows the shape of the sample so that the ultrasonic wave propagates through the cleaning liquid from the lower side to the upper side of the circular figure. The removal rate of adhering matter (particle removal rate) was measured using a wafer forcibly contaminated with SiN particles.

  As can be seen from FIG. 4, if the number of detected bubbles is increased from 30/10 ml, the deposit removal rate also increases, but if it exceeds 65/10 ml, the number starts to decrease. This is considered to be because if the number of bubbles 20 growing as uniform nuclei increases too much, the ultrasonic waves that are propagated are absorbed, reflected, and scattered, so that the removal rate of adhering substances decreases. In the circular diagram shown at the bottom of the graph, the upper adhering material is not removed at 85 / 10ml and 100 / 10ml because the ultrasonic wave propagating from below is not propagated upward and cavitation occurs. It is thought that it is difficult to do. In addition, when it is set to 100 pieces / 10 ml, the removal rate is improved. However, this is because the removal rate of the lower part of the circular figure was high, and the deposits on the upper part were not removed.

  Thus, there exists a suitable range for the generation amount (number of bubbles) of the bubbles 20 with respect to the cleaning effect. This range cannot be determined uniformly because it is affected by the type of cleaning liquid and the amount of dissolved gas. For example, the maximum removal rate is shown in the vicinity of 65/10 ml under the above-mentioned conditions, but the number of bubbles in which this peak value appears changes as the cleaning liquid conditions change. However, if the measurement as shown in FIG. 4 is performed in advance for each condition such as the cleaning liquid, effective and efficient cleaning can be performed based on the measurement value. This will solve this problem.

  Next, returning to FIG. 1, the ultrasonic cleaning system according to the present embodiment will be described. The ultrasonic cleaning system 1 of this specific example has a configuration in which bubbles 20 (bubbles that do not collapse) that grow as uniform nuclei are measured and cleaned. In the ultrasonic cleaning system 1, the ultrasonic oscillating means 5 vibrates by the high frequency power supplied from the oscillation power source 6, and ultrasonic waves oscillate. The ultrasonic wave oscillated from the ultrasonic oscillating means 5 is propagated to the cleaning liquid 2 via the ultrasonic wave propagating liquid inside the indirect tank 4 and the direct tank 3. As a result, cavitation occurs in the cleaning liquid 2 and the object to be cleaned W is cleaned.

  The cleaning liquid 2 supplied from the cleaning liquid supply means (not shown) via the conduit 10 overflows directly from the periphery of the opening of the tank 3 and is discharged to the cleaning liquid recovery means (not shown) via the trough 11 and the drain pipe 12. That is, since the cleaning liquid 2 can flow directly inside the tank 3 from the bottom toward the opening, the deposits removed from the surface of the object to be cleaned W are directly discharged outside the tank 3 so as to ride on this flow. Will be.

  The amount of bubbles contained in the cleaning liquid 2 extracted through the sampling tube 13 is measured by the bubble amount measuring means 14, and this measured value is sent to the control means 15. The oscillation output of the ultrasonic oscillating means 5 is controlled by the control means 15 so that the transmitted measurement value falls within a predetermined range (value) as described above. The oscillation output of the ultrasonic oscillating means 5 is controlled by controlling the high frequency power supplied by the control means 15.

  FIG. 5 is a schematic view for illustrating the bubble amount measuring means 14 by the laser scattering method. A measurement tank 16 communicating with the sampling pipe 13 and the discharge pipe 21 is provided inside the bubble amount measuring means 14, and a laser diode light projecting part 17 and a light receiving part 18 are provided in the measurement tank 16. The cleaning liquid 2 extracted by a pump (not shown) is supplied to the measurement tank 16, but when the bubbles 20 are present in the cleaning liquid, the laser light 19 is scattered and a part of the scattered light 19 a enters the light receiving unit 11. Since the amount of laser light incident on the light receiving unit 11 increases according to the amount of bubbles, the number and size of bubbles can be known by measuring the voltage output from the light receiving unit 11. This method can measure even small bubbles with a diameter of about 0.3 micrometers. After the measurement, the cleaning liquid 2 is discharged to the tub 11 through the discharge pipe 21. Note that other optical means such as a light emitting diode can be used as a light source for measuring the amount of bubbles.

  Further, the light projecting unit 17 and the light receiving unit 18 may be arranged substantially coaxially, and the light amount of the transmitted light attenuated by the bubbles in the laser light 19 may be measured by the light receiving unit 18. With this method, it is possible to measure bubbles having a larger diameter.

Next, the ultrasonic cleaning method according to the embodiment of the present invention will be described.
In this case as well, a case will be described where bubbles 20 (bubbles that do not collapse) that grow as uniform nuclei are measured and washed.

FIG. 6 is a flowchart for illustrating the procedure of the ultrasonic cleaning method according to the embodiment of the invention.
First, the article to be cleaned W is directly placed in the tank 3 by a conveying means (not shown) (step 1). The cleaning liquid 2 is directly supplied into the tank 3 from the cleaning liquid supply means (not shown) via the pipe line 10 (step 2). High frequency power is supplied from the oscillation power source 6 to the ultrasonic oscillation means 5 to oscillate ultrasonic waves (step 3). The cleaning liquid 2 is extracted through the sampling tube 13, and the amount of bubbles contained in the cleaning liquid 2 is measured by the bubble amount measuring means 14 (step 4). In addition, the measurement object of the bubble amount was the number of bubbles as described above. A measured value of the amount of bubbles (the number of bubbles) is sent to the control means 15 to determine whether or not it is within a predetermined range (value) (step 5). This predetermined range (value) can be individually input by an operator or sent from a database (not shown). When the measured value of the amount of bubbles (the number of bubbles) is not within a predetermined range (value), the oscillation output of the ultrasonic oscillation means 5 is controlled by the control means 15 (step 6). After a predetermined time has elapsed, or after confirming the cleaning condition by a particle measuring means (not shown), the article W to be cleaned is directly carried out of the tank 3 by a conveying means (not shown) (step 7).

  Thereafter, if necessary, the cleaning operation can be continued by repeating these steps. In addition, prior to the cleaning of the workpiece W, the tank 3 can be cleaned in advance. In this way, not only can the deposits removed in the previous washing be prevented from adhering again to the workpiece W, but also the amount of bubbles (number of bubbles) can be measured because the deposits are less likely to be measured as bubbles. This also increases the measurement accuracy.

  In addition, although the above-mentioned description is a case where the amount of bubbles (number of bubbles) is measured during the cleaning of the object to be cleaned W, the amount of bubbles (number of bubbles) before the cleaning (the state where there is no object to be processed W). It is also possible to perform measurement, determine an appropriate oscillation output of the ultrasonic oscillating means 5, and perform cleaning with the oscillation output. In this way, since the removed deposits are not measured as bubbles, the measurement accuracy of the amount of bubbles (number of bubbles) is further increased.

Next, an ultrasonic cleaning system for measuring the amount of bubbles 22a and 22b to be crushed and performing cleaning will be described.
FIG. 7 is a schematic diagram for explaining an ultrasonic cleaning system according to another embodiment of the present invention. In this figure, the same elements as those described above with reference to FIG.

  The ultrasonic cleaning system 25 of this specific example is provided with radical trapping agent adding means 23. Further, the sampling tube 13 passes through the tank 3 directly from the outside and communicates with the bubble amount measuring means 14. The sampling tube 13 is supplied with a monitor liquid composed of the same liquid as the cleaning liquid from the outside, and a radical trapping agent is added from the radical trapping agent adding means 23 and directly passes through the tank 3, It is guided to the bubble amount measuring means 14. That is, the monitor liquid to which the radical trapping agent is added passes directly through the tank 3 without being mixed with the cleaning liquid stored in the direct tank 3 in which the cleaning object W such as a wafer is deposited.

  The radical trapping agent adding means 23 is electrically connected to the control means 15. The other end of the sampling tube 13 is connected to an ESR (Electron Spin Resonance) spectrometer 24. The ESR spectroscopic device 24 and the control means 15 are electrically connected. However, the ESR spectroscopic device 24 and the control means 15 do not necessarily need to be connected.

Next, the operation will be described, but the description of the same components as those described above with reference to FIG. 1 will be omitted.
The radical trapping agent adding unit 23 has a function of adding a predetermined amount of radical trapping agent to the monitor liquid supplied to the sampling tube 13 based on a command from the control unit 15. The monitor liquid to which the radical trapping agent is added generates radicals by receiving ultrasonic waves in the direct tank 3 in which the object to be cleaned W is accommodated. The monitor liquid containing radicals stabilized by the added radical trapping agent flows through the sampling tube 13 and is sent to the ESR spectroscopic device 24 to measure the amount of radicals. The measured radical amount is sent to the control means 15, and based on this, the amount of bubbles 22a and 22b to be crushed is determined.

Next, a cleaning method will be described.
FIG. 8 is a flowchart for illustrating the procedure of the ultrasonic cleaning method according to another embodiment of the invention.

  A predetermined amount of radical trapping agent is added from the radical trapping agent adding means 23 to the monitor liquid flowing through the sampling tube 13 (step 11). The monitor liquid is extracted through the sampling tube 13 and sent to the ESR spectroscope 24 to measure the radical amount (step 12). The measured value of the radical amount is sent to the control means 15 to determine whether or not it is within a predetermined range (value) (step 13). This predetermined range (value) can be individually input by an operator or sent from a database (not shown). When the measured value of the radical amount is not within the predetermined range (value), the oscillation output of the ultrasonic oscillation means 5 is controlled by the control means 15 (step 14). When the oscillation output of the ultrasonic oscillating means 5 is confirmed such that the measured value of the radical amount falls within a predetermined range (value), the object to be cleaned W is subsequently cleaned with this output. Further, the placement and unloading of the article W to be cleaned are the same as in the case of FIG.

  7 illustrates a system in which the sampling tube 13 that directly passes through the tank 3 is provided, and the monitor liquid added with the radical trapping agent is flowed to measure radicals by the ESR spectroscopic device 24. However, the present invention is not limited thereto. Is not limited. In addition to this, for example, a measurement cell in which a monitor liquid added with a radical trapping agent is enclosed is prepared, and this is directly put into the tank 3 to form radicals by ultrasonic waves. 3 may be taken out and the amount of radicals may be measured by an ESR spectrometer. In any case, according to the present invention, since bubbles generated by ultrasonic waves can be directly measured in the tank 3, accurate feedback control is possible.

FIG. 9 is a schematic view for illustrating the bubble amount measuring means 29 by the ultrasonic method.
A measurement tank 16 communicating with the sampling tube 13 and the discharge pipe 21 is provided inside the bubble amount measuring means 29, and an ultrasonic oscillator 27 and an ultrasonic receiver 28 are provided in the measurement tank 16. The cleaning liquid 2 extracted by a pump (not shown) is supplied to the measurement tank 16, but when bubbles 20 are present in the cleaning liquid, the ultrasonic waves 30 are scattered and the amount of ultrasonic waves incident on the ultrasonic receiver 28 is reduced. Since the amount of ultrasonic waves incident on the ultrasonic receiver 28 is attenuated according to the amount of bubbles, the number and size of bubbles can be known by measuring the voltage output from the ultrasonic receiver 28. After the measurement, the cleaning liquid 2 is discharged to the tub 11 through the discharge pipe 21.

  The laser scattering type bubble amount measuring means 14 illustrated in FIG. 5 can measure even the small diameter bubbles with high sensitivity, and is suitable for measuring the number, size, and particle size distribution of the small diameter bubbles. However, on the other hand, there is a possibility that the deposit (fine particles) removed by the cleaning is erroneously detected. The bubble amount measuring means 29 by the ultrasonic method illustrated in FIG. 9 has an advantage that the sensitivity to minute bubbles is reduced, but there is little possibility of erroneously detecting the adhered matter (fine particles) removed by the cleaning. Therefore, the laser scattering method and the ultrasonic method can be properly used depending on the amount of deposits (fine particles) removed by cleaning. In addition, bubbles having a small diameter can be selectively used as a laser scattering method, and bubbles having a relatively large size can be used as an ultrasonic method. Alternatively, both types of bubble amount measuring means can be used to determine abnormality.

FIG. 10 is a schematic view illustrating an ultrasonic cleaning system including a bubble amount measuring unit 14 using a laser scattering method and a bubble amount measuring unit 29 using an ultrasonic method.
Thus, if both types of bubble amount measuring means are provided in advance, the above-described proper use can be easily performed. In FIG. 10, the bubble amount measuring means 14 by the laser scattering method and the bubble amount measuring means 29 by the ultrasonic method are connected in parallel, but they may be connected in series.

  As described above, as can be understood from the above description, according to the ultrasonic cleaning system and the ultrasonic cleaning method of the present invention, the amount of bubbles generated in the cleaning liquid can be controlled, so that the cleaning effect and the cleaning efficiency are high. Can be washed.

  Although the present invention has been described with reference to specific examples, the present invention is not limited to these specific examples. Regarding the ultrasonic cleaning system and the bubble amount measuring means according to the above specific examples, those appropriately modified by those skilled in the art are also included in the scope of the present invention as long as they have the characteristics of the present invention. For example, the direct tank, the indirect tank, the ultrasonic oscillation means, and the elements attached to these are not limited to the illustrated shapes and sizes, and the cross-sectional shape, wall thickness, opening shape and size, material, etc. Within the scope of the present invention, the same effects can be obtained with appropriate modifications, and these are also included in the scope of the present invention.

It is a schematic diagram for demonstrating the ultrasonic cleaning system of this embodiment. It is the schematic diagram which expanded the interface vicinity of the to-be-cleaned object hold | maintained in the washing | cleaning liquid. It is a graph for demonstrating the relationship between the generation amount (number of bubbles) of the bubble which grows as a uniform nucleus, and the output of an ultrasonic oscillation means. It is a graph for demonstrating the relationship between the generation amount (number of bubbles) of the bubble which grows as a uniform nucleus, and the removal rate of a deposit. It is a schematic diagram for illustrating the bubble amount measuring means by a laser scattering method. It is a flowchart for illustrating the procedure of the ultrasonic cleaning method. It is a schematic diagram for demonstrating an ultrasonic cleaning system. It is a flowchart for illustrating the procedure of the ultrasonic cleaning method. It is a schematic diagram for illustrating the bubble amount measuring means by the ultrasonic method. It is a schematic diagram for illustrating an ultrasonic cleaning system including a bubble amount measuring unit using a laser scattering method and a bubble amount measuring unit using an ultrasonic method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ultrasonic cleaning system, 2 Cleaning liquid, 3 Direct tank, 4 Indirect tank, 5 Ultrasonic oscillation means, 6 Oscillation power supply, 14 Bubble quantity measuring means, 15 Control means, 20 Bubble, 22a Bubble, 22b Bubble, 23 Radical trap agent Addition means, 29 Bubble amount measurement means, 31 Ultrasonic cleaning system

Claims (9)

An ultrasonic cleaning system for cleaning an object to be cleaned by propagating ultrasonic waves to a cleaning liquid,
A cleaning tank for storing the cleaning liquid and storing and cleaning the object to be cleaned;
Ultrasonic oscillation means for generating the ultrasonic waves;
Measuring means for measuring the amount of bubbles generated in the washing tank;
Control means for controlling the oscillation output of the ultrasonic oscillation means based on the measurement result of the amount of bubbles;
An ultrasonic cleaning system comprising:   The ultrasonic cleaning system according to claim 1, wherein the measuring unit is capable of measuring radicals generated when bubbles are crushed.   The ultrasonic cleaning system according to claim 1, wherein the control unit controls an oscillation output of the ultrasonic oscillation unit so that the measured amount of bubbles becomes a predetermined value.   The ultrasonic cleaning system according to claim 1, wherein the measuring unit is capable of measuring the number of bubbles. An ultrasonic cleaning method for cleaning an object to be cleaned by propagating ultrasonic waves generated by an ultrasonic oscillator to a cleaning liquid,
Measure the amount of bubbles generated in the cleaning tank in which the object to be cleaned is accommodated and cleaned,
An ultrasonic cleaning method, comprising: controlling an oscillation output of the ultrasonic oscillation means based on the result.   The ultrasonic cleaning method according to claim 5, wherein the measurement of the amount of bubbles generated in the cleaning liquid is performed by measuring radicals generated when the bubbles are crushed.   6. The ultrasonic cleaning method according to claim 5, wherein the oscillation output of the ultrasonic oscillation means is controlled so that the measured amount of bubbles becomes a predetermined value.   The ultrasonic cleaning method according to any one of claims 5 to 7, wherein the amount of bubbles generated in the cleaning liquid is measured when there is no object to be cleaned in the cleaning liquid. The ultrasonic cleaning method according to claim 5, wherein the measurement of the amount of bubbles generated in the cleaning liquid is performed when the object to be cleaned is present in the cleaning liquid.