JP2001149873A - Washing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To supply washing water always held to a predetermined dissolved air concentration to washing tanks in a washing apparatus having a plurality of washing tanks arranged thereto and successively feeding an article to be washed to the washing tanks to wash the same while supplying washing water comprising air-dissolved water to the washing tanks. SOLUTION: The discharged water from a washing tank 32 is guided to a front stage washing tank 31 by a liquid feed line 39 and an impurity removing device 42 is provided to the liquid feed line 39 and an air dissolving device 43 for dissolving air in the discharged water from which impurities are removed by the impurity removing device 42 is provided. A liquid feed line 57 for circulating discharged water is provided to a washing tank 31 among a plurality of the washing tanks, and the impurity removing device 42 and the air dissolving device 43 are provided to the liquid feed line 57.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning apparatus capable of stably cleaning a product in a wet cleaning step in the production of electronic parts / members and optical / magnetic storage media.

[0002]

2. Description of the Related Art In the manufacturing process of materials for electronic parts and magnetic storage media, the presence of impurities such as metals, fine particles, organic substances and ionic components deteriorates the performance of products, so that these impurities must be removed as much as possible. Is desirable. For example, in the process of manufacturing a hard disk using aluminum as a material, nickel-phosphorous plating is applied to increase the surface hardness of a flat aluminum substrate, and then a metal such as cobalt is formed on the nickel-phosphorus-plated surface, and information is obtained by magnetic force. A storage layer is provided, and a protective layer for protecting the magnetic layer from contact with the magnetic head is formed thereon. These layers consist of extremely thin layers of several microns to several tens of microns, and if particulate dust is present on the surface before film formation, they appear as protrusions on the surface after film formation, resulting in uniform magnetization. And there is also a risk of damage due to contact with the magnetic head.

[0003] Sources of the fine particles include those originating from the environment such as contamination from the packaging material at the time of receiving the substrate, as well as a polishing step for flattening the substrate and a step of forming a base of nickel phosphorus plating. A process called texturing that damages the substrate is also a major cause. In a polishing step or a texturing step, a rotating polishing cloth or a polishing plate is pressed while slurry is applied to a substrate, and as a result, shavings from the abrasive grains in the polishing slurry or the substrate are generated.

[0004] Before the plating or the magnetic film forming process, cleaning for removing fine particles and the like adhering to the substrate surface is always performed. Examples of the cleaning method include batch processing in which a plurality of substrates are immersed in a cleaning tank containing a cleaning liquid at a time and processing, and single-wafer processing in which substrates are processed by rotating the substrates one by one and contacting the cleaning liquid.

[0005] In the case of batch processing, a cleaning apparatus having a plurality of cleaning tanks is generally used. Pure water or gas-dissolved water is used as the wash water. In recent years, a cleaning method using gas-dissolved water has become widespread. The gas-dissolved water includes reducing water and oxidizing water. The former is water whose oxidation-reduction potential is adjusted to a reducing region, and the latter is water whose potential is adjusted to an oxidizing region. In general, hydrogen water obtained by dissolving hydrogen gas in ultrapure water is used as reducing water, and the hydrogen water has an action of removing fine particles. Generally, ozone water obtained by dissolving ozone in ultrapure water is used as the oxidizing water, and the ozone water has an action of removing metals and organic substances.

A conventional cleaning apparatus will be described below, taking as an example the case where hydrogen water is used as gas-dissolved water.

FIG. 5 shows a conventional cleaning apparatus in which three cleaning tanks are arranged. First, an object to be cleaned 1 such as a semiconductor wafer is cleaned in a first cleaning tank 2 and then a second cleaning tank 3. The cleaning is performed in each cleaning tank while being sequentially transferred to the third cleaning tank 4. The ultrapure water produced by the ultrapure water producing apparatus 5 is sent to a hydrogen dissolving apparatus 6, where hydrogen water is produced and, if necessary, adjusted to weak alkaline by adding ammonia water. Hydrogen water is sent to the third washing tank 4 as washing water. The washing water used for washing in the tank 4 overflows the outside of the tank, flows into the lower receiving tank 7, and is sent to the second washing tank 3 in the preceding stage through the pipe 8. At this time, the washing water is purified by the activated carbon filter device 9 and the particulate matter removing filter device 10 along the way, and contaminants brought about by the washing are removed.

The washing water sent to the second washing tank 3 acts here as washing water for washing the object 1 to be washed in the tank 3, and the washing water provided for washing in the tank 3 is Overflowing outside the tank,
Thereafter, the water is sent to the first cleaning tank 2 by following the same route as described above, where it acts as cleaning water for cleaning the object 1 to be cleaned in the tank 2, and the overflow water after cleaning passes through the pipe 13. Out of the system.

The objects to be cleaned are sequentially sent out from the loader 14, conveyed to the respective cleaning tanks, cleaned, and stored in the unloader 15. Reference numeral 16 denotes a water pump.

FIG. 6 shows another embodiment of the conventional apparatus. In this apparatus, the hydrogen water produced by the hydrogen dissolving device 6 is supplied to the second cleaning tank 3 and the third cleaning tank 4, and the first cleaning tank 2 is supplied with ultrapure water. I have. In the first cleaning tank 2 and the third cleaning tank 4, overflow water flowing down to the receiving tanks 17 and 7 is supplied to pipes 18 and 11, respectively.
After flowing out of the system, the overflow water flowing down to the receiving tank 19 in the second washing tank 3 is subjected to the impurity removal treatment by the activated carbon filter device 9 and the fine particle removal filter device 10 through the pipe 20. It is again guided to the second washing tank 3 and used for circulation. That is, the pipe 21 for introducing the washing water into the washing tank 3 is connected to the pipe 20 for flowing the overflow water and the pipe 23 for introducing the hydrogen water through the three-way valve 22 to mix the overflow water and the hydrogen water. The water is configured to flow into the second cleaning tank 3 through the pipe 21. Reference numeral 24 denotes a pipe for discharging surplus water from the receiving tank 19.

[0011]

In the conventional apparatus shown in FIGS. 5 and 6, since the cleaning water supplied to the cleaning tank is exposed to the atmospheric pressure, the dissolved hydrogen in the cleaning water diffuses into the atmosphere. However, at the same time, a phenomenon occurs in which air dissolves in the washing water, which causes a problem that the concentration of dissolved hydrogen in the washing water decreases. In particular, there is a problem that the defoaming of dissolved hydrogen is promoted when a filter filtration treatment is performed with an activated carbon filter or a filter for removing fine particles. As a result of the decrease in the concentration of dissolved hydrogen in the washing water, the dissolved hydrogen as overflow water is sent to the preceding washing tank (FIG. 5) or when it is repeatedly used in the same tank (FIG. 6). There is a problem in that the use of cleaning water having a reduced concentration causes a reduction in cleaning performance, and contaminants are brought into a subsequent cleaning tank.

The above is not limited to the case of hydrogen water, but also applies to the case of gas-dissolved water in which ozone or another gas is dissolved. In general, since the cleaning process cannot be performed in a closed system, escape of dissolved gas from the cleaning water and a decrease in the cleaning ability due to the escape are problems inevitable. If the method of continuously supplying gas-dissolved water produced by the gas dissolving device to each of the cleaning tanks and continuously discharging the overflow water after cleaning is adopted, new cleaning water is always supplied to the cleaning tank. Therefore, even if dissolved gas escapes from the cleaning water, a predetermined cleaning ability can be maintained. However, when such a method is employed, the amount of washing water used increases, which leads to an increase in processing costs, which is not economically advantageous.

The present invention has been made in view of the above points,
In order to make effective use of the washing water, a method of sequentially sending the discharged water from the washing tank to the preceding washing tank and using the discharged water as the washing water in the preceding washing tank is adopted. It is an object of the present invention to provide a cleaning apparatus capable of always supplying cleaning water having a predetermined dissolved gas concentration to a cleaning tank in any case where a method of circulating and using a single cleaning tank is used.

[0014]

According to the present invention, there are provided (1) a plurality of cleaning tanks arranged, objects to be cleaned are sequentially sent to each of the cleaning tanks, and cleaning water composed of gas-dissolved water is supplied to the cleaning tank to be cleaned. In a cleaning device for cleaning a cleaning object, an impurity removing device is provided in a liquid sending line that guides water discharged from a cleaning tank to a preceding cleaning tank or the same cleaning tank, and an impurity removing process is performed by the impurity removing device. (2) a cleaning device according to (1), wherein the gas is hydrogen gas or ozone gas, and (3) a gas. (1) The cleaning device according to the above (1), wherein the gas supply device connected to the dissolving device is a water electrolysis device or a gas cylinder, and (4) the degassing device provided between the impurity removing device and the gas dissolving device. ) Described washing device, (5) multiple A cleaning device is provided to sequentially wash the objects to be cleaned to each of the cleaning tanks and supply cleaning water composed of gas-dissolved water to the cleaning tank to clean the objects to be cleaned. And a gas dissolving device for dissolving gas in the effluent that has been subjected to the impurity removal treatment by the impurity removal device, and a cleaning tank of the final stage. The gist of the present invention is a washing apparatus characterized in that an ion-adsorbing film apparatus is provided in addition to the impurity removing apparatus and the gas dissolving apparatus in a liquid sending line between the washing tank in the preceding stage.

[0015]

FIG. 1 shows a first embodiment of the present invention, in which three cleaning tanks 30, 31, and 32 are arranged in a horizontal direction, and each cleaning tank 30, 31, and 32 is disposed below the cleaning tanks. Are provided with receiving tanks 33, 34, 35 for storing overflow water from the respective washing tanks. The number of washing tanks is not limited to three, but is optional. Reference numeral 36 denotes a loader for holding and storing the object to be cleaned such as a semiconductor wafer, and reference numeral 37 denotes an unloader for holding and storing the object to be cleaned after cleaning.

A pipe 38 for supplying gas-dissolved water is provided to the third cleaning tank 32, which is the last-stage cleaning tank, and an ultrapure water producing apparatus 77 and a gas dissolving apparatus 78 are connected to the pipe 38. I have. Hereinafter, an example of the present invention will be described for a case where hydrogen water obtained by dissolving hydrogen gas in ultrapure water is used as gas-dissolved water.

A gas supply device 47 is connected to the gas dissolving device 78. A water electrolysis device is used as the gas supply device 47, and the hydrogen gas generated in the cathode chamber of the water electrolysis device is supplied to the gas dissolution device 78. The ultrapure water produced by the ultrapure water producing apparatus 77 is dissolved in the gas dissolving apparatus 7
8, while the hydrogen gas produced by the gas supply device 47 is guided to the device 78, in which the hydrogen gas is dissolved in ultrapure water to produce hydrogen water. As described later, the gas dissolving device 78 may have the same structure as that of the gas dissolving device 43 provided in the middle of the drainage water supply line from the cleaning tank. If necessary, an ammonia water adding means (not shown) is provided, and the pH of the hydrogen-dissolved water is made weakly alkaline by adding the ammonia water. The dissolved hydrogen concentration in the hydrogen water is preferably from 0.3 to 2.0 mg / L. If the concentration is less than 0.3 mg / L, the effect of removing fine particles is inferior. If the concentration exceeds 2.0 mg / L, foaming becomes remarkable in the washing tank, and the washing effect is reduced.

The ultrapure water production apparatus 77 includes a primary treatment system apparatus combining a coagulation settling apparatus, a sand filtration apparatus, an activated carbon filtration apparatus, a reverse osmosis membrane apparatus, a two-bed three-column ion exchange apparatus, a precision filter apparatus, and the like. It is composed of a secondary treatment system device combining an ultraviolet irradiation device, a mixed-bed polisher, an ultrafiltration membrane device and the like. Raw water is treated by a primary treatment system to obtain primary pure water, and the primary pure water is secondarily treated by a secondary treatment system to remain in the primary pure water, fine particles, colloidal substances, organic substances, metals, Ultrapure water is obtained by removing as much as possible anions and dissolved oxygen.

The distance between the receiving tank 35 of the third cleaning tank 32 and the preceding second cleaning tank 31 and the distance between the receiving tank 34 of the second cleaning tank 31 and the first cleaning tank 30 of the preceding stage are each A liquid sending line 39, 40 for guiding the discharged water of the above to the preceding washing tank is provided, and a water sending pump 41,
An impurity removing device 42 and a gas dissolving device 43 are sequentially provided. The impurity removing device 42 includes an activated carbon filter device 44 and a filter device 45 for removing fine particles, but is not limited thereto. In short, any device can be used as long as it can remove contaminants brought about by washing.

The gas dissolving device 43 is for dissolving the hydrogen gas in the effluent water subjected to the impurity removing treatment by the impurity removing device 42, and the device 43 has a gas supply for supplying the hydrogen gas to the device. The device 46 is connected. It is preferable to use a water electrolysis device as the gas supply device 46. The water electrolysis apparatus includes an electrolytic cell 52 having an anode and a cathode disposed through a diaphragm, and a power supply device 53 for the electrolytic cell 52.
The hydrogen gas generated in the cathode chamber is
3 and hydrogen gas is dissolved in the discharged water in the device 43. The gas supply device 46 includes a gas dissolving device 43 provided on the liquid sending line 39 and a gas dissolving device 4 provided on the liquid sending line 40.
3 are connected to both via pipes 48 and 49, respectively.

The gas supply device 47 provided in the hydrogen water supply line may be used without providing the gas supply device 46 in the line for sending the discharged water to the preceding washing tank. That is, in addition to providing a pipe for connecting the gas dissolving device 78 to the gas supply device 47,
In addition, a pipe connecting the gas dissolving devices 43, 43 at 0 is also provided.
May be supplied with hydrogen gas.

As the gas dissolving device 43, it is preferable to use a gas-liquid separation membrane module filled with a hollow fiber membrane.
In this apparatus, hydrogen gas is introduced inside or outside the hollow fiber membrane, and discharged water is introduced outside or inside the hollow fiber membrane. Hydrogen gas permeates the membrane and dissolves in the effluent, and as a result, effluent with an improved hydrogen gas concentration is obtained.

Reference numeral 51 denotes a dissolved gas concentration meter connected to the outlet side of the gas dissolving device 43, which detects the hydrogen gas concentration of the discharge water (wash water) flowing out from the gas dissolving device 43 and controls the hydrogen gas concentration. Work. That is, when the hydrogen gas concentration of the discharged water has not reached the set value, a signal is output from the dissolved gas concentration meter 51 to the power supply device 53 of the gas supply device 46. As a result, the current value of the power supply 53 increases,
The amount of hydrogen gas generated increases and the dissolved concentration of hydrogen gas increases,
The concentration of dissolved hydrogen gas is adjusted to a predetermined value. Conversely, when the hydrogen gas concentration exceeds the set value, the current value of the power supply device 53 is reduced by signal processing, and the amount of generated hydrogen gas is reduced. As a result, the concentration of dissolved hydrogen gas decreases,
The concentration of dissolved hydrogen gas is adjusted to a predetermined value.

The gas dissolving device 43 is not limited to the one having the hollow fiber membrane structure described above. For example, a device for dissolving hydrogen gas by a bubbling method by supplying hydrogen gas to a discharge water storage tank, An apparatus or the like for dissolving hydrogen gas by supplying hydrogen gas to a rotary pump in a multiphase flow state may be used. As described above, the gas dissolving device 43 is a gas dissolving device 78 connected to the pipe 38 for supplying hydrogen water.
A device having the same structure as described above can be used.

An object 50 to be cleaned, such as a semiconductor wafer, is transferred from the loader 36 to the first cleaning tank 30 by a transfer device, immersed in cleaning water in the tank 30, and cleaned. After the cleaning is completed, the object 50 is transferred to the second cleaning tank 3
After completion of the cleaning, the wafer is similarly transferred to the third cleaning tank 32, where the final cleaning is performed. The object to be cleaned after the cleaning is transferred to the unloader 37 and stored and held.

Hydrogen water as cleaning water is sent through a pipe 38 to a cleaning device which is a use point. The washing water is supplied to the third washing tank 32, which is the last washing tank, and the object to be washed is washed. Wash water is continuously supplied to the washing tank 32, and the washing water overflowing from above the tank 32 flows down to the receiving tank 35 as discharge water, and is temporarily stored.

The discharged water in the receiving tank 35 continuously flows out of the tank through the piping 54 of the liquid sending line 39, is pumped by the pump 41, and flows through the liquid sending line 39. The discharged water is activated carbon filter device 44, and fine particle removal filter device 4
5, the contaminants in the discharged water are removed, and then sent to the gas dissolving device 43. On the other hand, hydrogen gas is supplied from the gas supply device 46 to the device 43, and the hydrogen gas is dissolved in the effluent in the device 43, and the hydrogen gas concentration of the effluent is reduced to a predetermined value (0.3 to 2.0 mg). / L is preferred). Here, in the cleaning tank 32, since the cleaning water is placed under an atmospheric pressure atmosphere, the dissolved hydrogen gas escapes into the atmosphere. The discharged water used for washing is defoamed by agitation by the pump 41, and the defoamed air bubbles are removed by the filter devices 44 and 45. In this way, the concentration of the dissolved gas in the discharged water is remarkably reduced, so that the hydrogen gas is sufficiently dissolved in the discharged water in the gas dissolving device 43, and the concentration of the hydrogen gas can be adjusted accurately and easily.

The effluent whose hydrogen gas concentration has been adjusted is supplied to the second cleaning tank 31 through the pipe 55 of the liquid sending line 39. The supplied discharge water acts as cleaning water for cleaning the object 50 in the cleaning tank 31.

The washing water in the washing tank 31 is similarly discharged to the outside of the tank through the receiving tank 34, and the discharged water is sent to the liquid sending line 40, and the filter device 4 is provided in the same manner as described above.
After the contaminants are removed by 4 and 45, the hydrogen gas concentration is adjusted by the gas dissolving device 43.

The discharged water whose hydrogen gas concentration has been adjusted is led to the first cleaning tank 30, where the discharged water acts as cleaning water for cleaning the object 50 in the first cleaning tank 30. The cleaning tank 30 is used for cleaning in the cleaning tank 30 and the receiving tank 3
The washing water overflowing to 3 is discharged out of the system through a pipe 56.

FIG. 2 shows a second embodiment of the present invention, in which the washing water is circulated only in the second washing tank 31. The discharged water discharged from the receiving tank 34 is supplied to the second washing tank 3
1. A liquid feed line 57 is provided for leading to the liquid supply line 1 and the water feed pump 41 and the activated carbon filter device 4 are connected to the liquid feed line 57.
4. Filter device 45 for removing fine particles, gas dissolving device 4
3 are arranged. A three-way valve 58 is provided on the outlet side of the gas dissolving device 43, and the three-way valve 58
7 are connected to a pipe 93 for supplying cleaning water guided from the gas dissolving device 78.

In this embodiment, the gas supply device 46
A hydrogen gas cylinder 94 is used. 61 is a pressure regulating valve. 62 is a pipe for supplying hydrogen water as cleaning water to the third cleaning tank 32, 63 is a first cleaning tank 30
This is a pipe for supplying ultrapure water as washing water.

The object 50 to be cleaned is cleaned with ultrapure water in the first cleaning tank 30, and the overflowing cleaning water is discharged through a pipe 56. Next, the object 50 to be cleaned is placed in the second cleaning tank 31.
Is washed with hydrogen water. The effluent from the tank 31 passes through the filter devices 44 and 45 and the gas dissolving device 4
The hydrogen gas concentration is adjusted by 3 and the discharged water whose hydrogen gas concentration has been adjusted is mixed with the hydrogen water supplied through the pipe 93, and this mixed water is supplied to the second cleaning tank 31 through the pipe 60. Is done.

A part of the washing water overflowing into the receiving tank 34 is
4, and the same amount of fresh water as the amount of discharged waste water is supplied through a pipe 93. With this configuration, it is possible to prevent the impurities that have not been completely removed by the filter devices 44 and 45 from being gradually concentrated.

In the third cleaning tank 32, the object 50 to be cleaned is cleaned with hydrogen water supplied through a pipe 62.
The overflowing wash water is discharged through a pipe 65.

FIG. 3 shows a third embodiment of the present invention, and the cleaning apparatus in this embodiment is suitable for cleaning with extremely high cleanliness. When high-purity finishing is required in the cleaning, it is necessary to perform particularly high-precision cleaning in the final-stage cleaning tank and the preceding-stage cleaning tank.

In this embodiment, as in the first embodiment, a liquid feed line for sending overflow water (discharge water) after washing to the preceding washing tank is provided between the receiving tank of each washing tank and the preceding washing tank. Have been. Reference numeral 66 denotes a liquid sending line provided between the receiving tank 69 and the preceding cleaning tank 70 in the final cleaning tank 68.
Is a liquid sending line provided between the receiving tank 71 of the preceding washing tank 70 and the preceding washing tank.

Each of the liquid sending lines 66 and 67 and the liquid sending line 6
A pump 41 for water supply, a filter 45 for removing fine particles, a degassing membrane device 72, and a gas dissolving device 43 are sequentially provided in a liquid sending line (not shown) located at a stage preceding the line 7, respectively. A vacuum pump 74 is connected to the film membrane device 72. The degassing membrane device 72 includes a gas-liquid separation membrane, and performs an action of separating dissolved gas in wastewater.

In the liquid sending line 66, in addition to the above-described structure, an ion adsorption membrane device 73 is provided at the outlet side of the gas dissolving device 43.
Is provided. The ion-adsorbing membrane provided in the ion-adsorbing membrane device 73 is a hollow fiber-like porous membrane in which a polymer chain having an ion-exchange group is retained inside the membrane, and has a content of 0.2 to 10 meq. A hollow fiber porous membrane having an ion exchange group and having an average pore diameter of 0.01 to 1 μm is preferred. Examples of the ion adsorption membrane include an anion adsorption membrane having an anion exchange ability, a cation adsorption membrane having a cation exchange ability, and a chelate adsorption membrane having a chelation ability.
Two or three of these adsorption films are used in appropriate combination. The ion-adsorbing film has a function of adsorbing ammonium ions, chlorine ions, sulfate ions and the like in the discharged water.

In this embodiment, hydrogen water as cleaning water is supplied from a pipe 62 to a cleaning tank 68 at the final stage to clean an object to be cleaned, and cleaning water overflowing from the tank 68 is sent as discharge water. After being sent to the liquid line 66 and subjected to the impurity removal treatment by the particulate removal filter device 45, the deaeration treatment is performed by the deaeration film device 72. The dissolved gas separated here is exhausted out of the system by the vacuum pump 74. As described above, the dissolved gas in the discharged water is separated by the degassing membrane device 72 and exhausted out of the system by the vacuum pump 74. And a sufficient amount of hydrogen gas can be dissolved in the effluent water.

After adjusting the dissolved hydrogen concentration of the discharged water in the gas dissolving device 43, the discharged water is led to the ion adsorbing device 73, where a small amount of anion component and cation component which cannot be removed by the filter device 45 for removing fine particles. And metal removal. The discharged water thus purified with high purity is supplied to the cleaning tank 70 in the preceding stage as cleaning water. The washing water in the tank 70 has the same water quality as the washing water in the final washing tank 68.
High-precision cleaning of the object to be cleaned 50 is possible. That is, according to the apparatus of the present embodiment, the specific resistance of the cleaning water in the final cleaning tank 68 and the preceding cleaning tank 70 is 17M.
High-precision cleaning that satisfies the cleaning condition of Ω · cm or more can be realized.

The effluent as overflow water in the washing tank 70 flows out to the liquid sending line 67, and in the process of being sent along the liquid sending line 67, the above-described filtering, deaeration, and hydrogen gas concentration adjustment. Are sequentially performed, and the discharged water after each treatment is guided to a cleaning tank in a stage preceding the cleaning tank 70, and is used as cleaning water. Hereinafter, similarly, the discharged water is sequentially guided to the preceding washing tank and reaches the first washing tank 75. The discharged water here is discharged out of the system through a pipe 76.

In the embodiment shown in FIGS. 1 and 2, between the filter devices 44 and 45 and the gas dissolving device 43, the same deaeration membrane device 72 and the same as those described in the embodiment shown in FIG. A vacuum pump 74 may be provided. Further, the present invention is not limited to the structure in which the washing water overflows from the upper part of the washing tank. For example, a drain pipe is provided in the washing tank without providing a receiving tank, and the washing water (discharge water) is sent through the drain pipe. You may make it send to a line.

In the present invention, ozone water can be used as cleaning water other than hydrogen water. In the case of ozone water, the ozone dissolution concentration is preferably 0.05 to 100 mg / L.
Therefore, when the ozone gas is dissolved in the discharged water by the gas dissolving device to adjust the ozone dissolved concentration, it is preferable to adjust the concentration to the above numerical value.

Experimental Example 1 In the apparatus shown in FIG. 4, a cleaning tank 79, a receiving tank 80, a pipe 81, a filter 82 for removing fine particles, a degassing membrane device 83,
The gas-dissolved water was continuously supplied to the cleaning tank 79 until the gas-dissolver 84 and the pipe 85 were all filled with the gas-dissolved water. Gas-dissolved water as cleaning water was produced and supplied by an ultrapure water production device 86 and a gas dissolution device 87. 88 is a water electrolysis device, 89 is a vacuum pump, 90 is a pressure gauge, 91 is a flow meter, 92 is a three-way valve, and 97 is a gas supply device. Hydrogen gas and ozone gas were used as dissolved gases.

The gas dissolving water is circulated without supplying the gas from the gas dissolving device 84 to perform cleaning, and the measurement points A and
In B, C, and D, the dissolved gas concentrations were measured. The amount of circulating water was 3 L / min. Table 1 shows the results. From the table,
It can be seen that the dissolved gas concentration gradually decreases from point A to point D.

Next, the concentration of the dissolved gas when the gas was supplied from the gas dissolving device 84 was measured at the measurement point E. The results are shown in the same table. From the table, it can be seen that by supplying the gas with the gas dissolving device 84, gas dissolved water having the same dissolved gas concentration as the outlet water of the gas dissolving device 87 can be obtained.

[0048]

[Table 1]

Experimental Example 2 Using the apparatus shown in FIG. 4, hydrogen water was supplied as cleaning water.
Further, the glass substrate for the hard disk was washed by circulating in the system. The glass substrate was immersed in a solution in which alumina particles having an average particle size of 0.2 μm were dispersed in advance and contaminated, and was treated as an untreated product. The circulating water amount of the hydrogen water was 3 L / min.
The state of the cleaning effect when hydrogen gas was supplied from the gas dissolving device 84 and when hydrogen gas was not supplied was observed. Table 2 shows the results. From the results in the table, if you adjust the dissolved gas concentration,
It can be seen that even if the discharged water discharged from the cleaning tank is circulated and used repeatedly, high-purity cleaning can be performed without supplying fresh cleaning water from outside the system as needed.

[0050]

[Table 2]

[0051]

According to the present invention, an impurity removing device is provided in the middle of a liquid sending line for guiding the water discharged from the washing tank to the preceding washing tank or the same washing tank, and the impurity removing treatment is performed by the impurity removing apparatus. Since a gas dissolving device for dissolving gas in the discharged water is provided, the cleaning water supplied to the cleaning tank is exposed to the atmospheric pressure, and the dissolved gas in the cleaning water diffuses into the atmosphere, Even in the situation where the dissolved gas concentration is reduced, by adjusting the dissolved gas concentration by the gas dissolving device, it is possible to always supply the washing water maintained at the predetermined dissolved gas concentration to the washing tank, and as a result, always high The cleaning ability can be maintained, and the effect of reliably preventing contaminants from being brought into the subsequent cleaning tank can be obtained.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a first embodiment of the present invention.

FIG. 2 is a schematic view showing a second embodiment of the present invention.

FIG. 3 is a schematic diagram showing a third embodiment of the present invention.

FIG. 4 is a schematic view showing an experimental example of the present invention.

FIG. 5 is a schematic view showing a conventional cleaning apparatus.

FIG. 6 is a schematic view showing another conventional cleaning apparatus.

[Explanation of symbols]

 30, 31, 32 Cleaning tank 39, 40 Liquid sending line 42 Impurity removing device 43 Gas dissolving device 50 Object to be cleaned

Claims (5)

[Claims] 1. A cleaning apparatus for arranging a plurality of cleaning tanks, sequentially sending an object to be cleaned to each of the cleaning tanks, and supplying cleaning water comprising gas-dissolved water to the cleaning tank to wash the objects to be cleaned. , An impurity removing device is provided in a liquid sending line for guiding discharged water from the washing tank to the preceding washing tank or the same washing tank,
A cleaning device comprising a gas dissolving device for dissolving a gas in effluent water subjected to an impurity removing process by the impurity removing device. 2. The cleaning apparatus according to claim 1, wherein the gas is hydrogen gas or ozone gas. 3. The cleaning device according to claim 1, wherein the gas supply device connected to the gas dissolving device is a water electrolysis device or a gas cylinder. 4. The cleaning device according to claim 1, further comprising a degassing device provided between the impurity removing device and the gas dissolving device. 5. A cleaning apparatus for arranging a plurality of cleaning tanks, sequentially sending an object to be cleaned to each of the cleaning tanks, and supplying cleaning water comprising gas-dissolved water to the cleaning tank to wash the objects to be cleaned. An impurity removing device and a gas dissolving device for dissolving gas in the discharged water subjected to the impurity removing process by the impurity removing device are provided in a liquid feed line for guiding the discharged water from the cleaning tank to the preceding cleaning tank. A cleaning device comprising an ion-adsorbing film device, together with the impurity removing device and the gas dissolving device, provided in a liquid sending line between a final cleaning bath and a preceding cleaning bath.