JP2012143708A - Washing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a washing method which gives an enough cleaning effect to an extent in which ultrasonic cleaning need not be combined only by high pressure jet washing using a gas solubility water or binary fluid washing to perform washing by low cost and a resource saving manner.SOLUTION: In the washing method in which a washing liquid or a mixed fluid of a washing liquid and a gas is discharged from a washing fluid discharge nozzle toward an object to be washed, and the object to be washed is washed by high pressure jet washing or binary fluid washing, a dissolved gas is made to be contained in the washing liquid introduced into the fluid delivery nozzle. The dissolved gas is dissolved into the washing liquid by that a prescribed pressure is applied. In the dissolving amount of the dissolved gas to the washing liquid, when the saturation solubility at a liquid temperature of the washing liquid is made a first saturation solubility and the saturation solubility in a state in which a prescribed pressure is applied keeping the liquid temperature of the washing liquid is made a second saturation solubility, 10-70% of the difference between the second saturation solubility and the first saturation solubility is added to the first saturation solubility.

Description

  The present invention effectively covers the surface of various materials to be cleaned, particularly electronic materials (electronic parts, electronic members, etc.) that require a high degree of cleanliness, such as silicon wafers for semiconductors and glass substrates for flat panel displays. It relates to a method of cleaning.

  Conventionally, in order to remove fine particles, organic substances, metals, etc. from the surface of electronic materials such as silicon wafers for semiconductors and glass substrates for flat panel displays, a high concentration based on hydrogen peroxide called RCA cleaning method A wet cleaning method at a high temperature with a chemical solution was performed. The RCA cleaning method is an effective method for removing metal or the like on the surface of the electronic material, but it is necessary to use a large amount of high-concentration acid, alkali, or hydrogen peroxide. Therefore, these large amounts of chemicals are discharged into the waste liquid, and there is a problem that a great burden is imposed on the neutralization treatment and precipitation treatment of the waste liquid and a large amount of sludge is generated. There is also a problem that a large amount of pure water or ultrapure water is required to rinse the object to be cleaned after cleaning.

  Therefore, gas-dissolved water prepared by dissolving a specific gas in pure water and adding a trace amount of chemicals as necessary has been used in place of high-concentration chemical solutions. If the cleaning is performed with gas-dissolved water, the burden of waste liquid treatment is reduced, and the amount of cleaning water used can be reduced because the problem of chemical residue on the object to be cleaned is small and the cleaning effect is high. Specific gases used for the gas-dissolved water as the electronic material cleaning water include nitrogen gas, hydrogen gas, oxygen gas, ozone gas, rare gas, carbon dioxide gas, and the like.

  On the other hand, as a cleaning method for various materials, there are known high-pressure jet cleaning in which a cleaning liquid is jetted from a nozzle at high pressure, and two-fluid cleaning in which a mixed fluid of cleaning liquid and gas (carrier gas) is jetted from a two-fluid nozzle. In high-pressure jet cleaning and two-fluid cleaning, a good cleaning effect is expected due to a physical action caused by a droplet of cleaning liquid ejected from a nozzle colliding with an object to be cleaned at high speed.

  Although cleaning with gas-dissolved water can provide a higher cleaning effect than cleaning with water that does not dissolve the gas, it is possible to obtain fine particles by simply performing high-pressure jet cleaning or two-fluid cleaning using gas-dissolved water. A sufficient cleaning effect for removing water is not obtained, and ultrasonic cleaning must be combined in order to fully develop the cleaning effect of the gas-dissolved water. For example, Patent Document 1 proposes a cleaning method in which hydrogen gas is dissolved in ultrapure water and hydrogen peroxide is added to the cleaning liquid, and the cleaning liquid is sprayed onto an object to be cleaned while irradiating ultrasonic waves. .

JP 2004-296463 A

  However, since the ultrasonic cleaning equipment is an expensive equipment, adopting ultrasonic cleaning is a factor that raises the cleaning cost. In addition, when ultrasonic cleaning with gas-dissolved water is applied to a glass substrate or the like, a large amount of cleaning water is required because it is necessary to apply ultrasonic waves to the substrate using a squall nozzle or the like. Therefore, in order to perform low-cost and resource-saving cleaning, it is necessary to achieve a sufficient cleaning effect that does not require the combination of ultrasonic cleaning only by high-pressure jet cleaning using gas-dissolved water or two-fluid cleaning. It has been.

  The present invention has been made in view of the above problems, and is a high-pressure jet cleaning or two-fluid cleaning method using gas-dissolved water, which has a high cleaning effect and realizes low cost and resource saving. The purpose is to provide.

  In order to achieve the above object, the present invention discharges a cleaning liquid or a mixed fluid of a cleaning liquid and a gas from a cleaning fluid discharge nozzle toward an object to be cleaned, and performs high-pressure jet cleaning or two-fluid cleaning on the object to be cleaned. In the cleaning method, the cleaning liquid introduced into the fluid discharge nozzle contains a dissolved gas, and the dissolved gas is dissolved in the cleaning liquid by applying a predetermined pressure, and the dissolved gas is transferred to the cleaning liquid. When the saturated solubility at the liquid temperature of the cleaning liquid is the first saturated solubility, and the saturated solubility in the state where the predetermined pressure is applied while maintaining the liquid temperature of the cleaning liquid is the second saturated solubility, Provided is a cleaning method, characterized in that 10 to 70% of the difference between the second saturated solubility and the first saturated solubility is added to the first saturated solubility (Invention 1).

  In a state where a predetermined pressure is applied to a cleaning liquid used in high-pressure jet cleaning or two-fluid cleaning, by dissolving a gas having a saturation solubility or higher at the liquid temperature of the cleaning liquid, the cleaning liquid or the cleaning liquid and the gas are discharged from the cleaning fluid discharge nozzle. When the mixed fluid is ejected as cleaning droplets toward the object to be cleaned, this supersaturated gas grows into bubbles under normal pressure. Alternatively, before the cleaning liquid or a mixed fluid of cleaning liquid and gas is discharged as cleaning droplets toward the object to be cleaned from the cleaning fluid discharge nozzle, this supersaturated gas becomes fine bubbles in the cleaning liquid, and many small droplets are present. Generated. When these bubbles and cleaning droplets are ejected from the cleaning fluid discharge nozzle toward the object to be cleaned, in addition to the physical cleaning action that these bubbles and cleaning droplets collide with the surface of the object to be cleaned, the bubble scrub effect, bubble collision Fine particles, organic substances, metals, and the like can be efficiently removed from the surface of the object to be cleaned by the physicochemical cleaning action such as the impact force and the adsorption force at the gas-liquid interface.

  On the other hand, when a gas having a solubility higher than the saturation solubility at the liquid temperature of the cleaning liquid is dissolved in a state where a predetermined pressure is applied, if too much gas is dissolved, the cleaning liquid or the cleaning liquid and the gas are discharged from the cleaning fluid discharge nozzle. When the mixed fluid is ejected as cleaning droplets toward the object to be cleaned, the diameter of bubbles generated from the gas in a supersaturated state becomes too large, which hinders the cleaning effect.

  According to the above invention (Invention 1), the cleaning liquid introduced into the fluid discharge nozzle can contain dissolved gas in a state in which a predetermined pressure is applied, and the amount of dissolved gas dissolved in the cleaning liquid can be reduced. When the saturated solubility at the liquid temperature is defined as the first saturated solubility, and the saturated solubility when the predetermined pressure is applied while maintaining the liquid temperature of the cleaning liquid is defined as the second saturated solubility, the second saturated solubility and the first saturated solubility are obtained. By adding 10 to 70% of the difference to the first saturated solubility, the diameter of bubbles generated from the gas in the supersaturated state does not become too large to impair the cleaning effect, so a high cleaning effect Can be realized.

  In the above invention (Invention 1), the dissolved gas is any one gas or a mixed gas of two or more of nitrogen gas, oxygen gas, carbon dioxide gas, hydrogen gas, ozone gas, clean air and rare gas. Is preferred (Invention 2).

  In the said invention (invention 1 and 2), it is preferable that the said predetermined pressure is a pressure 0.1-1.0 Mpa higher than a normal pressure.

  In the said invention (invention 1-3), it is preferable that the liquid which dissolves the said dissolved gas is a pure water or ultrapure water (invention 4), Moreover, in the said invention (invention 1-4), the said dissolved gas The liquid which dissolves may be deaerated (Invention 5). According to the said invention (invention 5), gas can be dissolved efficiently by carrying out the deaeration process of the liquid which dissolves dissolved gas.

  In the said invention (invention 1-5), the said washing | cleaning liquid may contain any one or two or more chemical | medical agents among an alkali, an acid, a chelating agent, and surfactant (invention 6). According to the said invention (invention 6), when a washing | cleaning liquid contains a chemical | medical agent, a much more favorable cleaning effect can be acquired.

  In the said invention (invention 1-6), it is preferable that the said washing | cleaning liquid exists in the state to which the said predetermined pressure was applied until it reaches | attains the pressure release point in the primary side of the said fluid discharge nozzle.

  According to the above invention (Invention 7), in the process of supplying the cleaning liquid to the fluid discharge nozzle, the cleaning liquid has a saturation solubility equal to or higher than the saturation solubility at the liquid temperature of the cleaning liquid until the pressure release point on the primary side of the fluid discharge nozzle is reached. The gas in the supersaturated state can be prevented from being bubbled. Here, the pressure release point includes a valve for adjusting the supply amount of the cleaning liquid to the fluid discharge nozzle.

  In the said invention (invention 7), it is preferable that the required time until the said washing | cleaning liquid passes the said pressure release point and is introduce | transduced into the said fluid discharge nozzle is less than 7 second (invention 8).

  Since the predetermined pressure is applied until the cleaning liquid reaches the pressure release point, the supersaturated gas is dissolved in the cleaning liquid without being bubbled. However, after the cleaning liquid has passed through the pressure release point, the atmosphere is in an open state, so that the gas dissolved in the cleaning liquid at a saturation solubility or higher begins to bubble. Here, if the time required for the cleaning liquid to pass through the pressure release point and be introduced into the fluid discharge nozzle becomes longer, the association of bubbles proceeds, and fine bubbles effective for cleaning may be lost.

  According to the above invention (Invention 8), the time required for the cleaning liquid to pass through the pressure release point and be introduced into the fluid discharge nozzle is suppressed to less than 7 seconds. Before the bubbles disappear, the cleaning liquid can be supplied to the fluid discharge nozzle.

  According to the cleaning method of the present invention, a high cleaning effect can be obtained by high-pressure jet cleaning or two-fluid cleaning using gas-dissolved water, and low-cost and resource-saving cleaning can be realized.

It is the schematic which shows the washing | cleaning system which concerns on one Embodiment of this invention.

  Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic view showing a cleaning system according to an embodiment of the present invention. The cleaning method of the present invention is for cleaning an object to be cleaned by high-pressure jet cleaning or two-fluid cleaning, but in this embodiment, two-fluid cleaning is adopted to clean the object to be cleaned. To do.

  A cleaning system 1 according to this embodiment includes a degassing membrane module 2, a gas dissolving membrane module 3, a drug supply device 5, a cleaning device 6, and a carrier gas supply device 7.

  The cleaning device 6 includes a chamber 61. In the chamber 61, a discharge nozzle 62 that discharges a cleaning fluid to the object to be cleaned 9 and a turntable 63 for setting the object to be cleaned 9 are provided. The chamber 61 is preferably capable of exhausting downward. This is to prevent the cleaning fluid discharged from the discharge nozzle 62 from flying up and contaminating the object 9 to be cleaned. By exhausting downward, the rising of the cleaning fluid is suppressed and contamination of the object 9 to be cleaned is prevented. Is prevented. The method for fixing the object 9 to be cleaned to the turntable 63 is not particularly limited, but in the present embodiment, the inside of the turntable 63 is evacuated to bring the object 9 to be cleaned into close contact with the turntable 63 (vacuum). Chuck) is used. As a specific method using a vacuum chuck, a space is formed between a rotating table 63 and a contact surface of the object 9 to be cleaned through a spacer made of rubber, for example, polytetrafluoroethylene, and the space is evacuated. Then, a method of bringing the turntable 63 and the object 9 to be cleaned into close contact with each other can be mentioned.

  The inside of the deaeration membrane module 2 is divided into a liquid phase chamber 21 and a gas phase chamber 22 by a gas permeable membrane 20. A raw water supply pipe 23 and a deaerated water supply pipe 24 are connected to the liquid phase chamber 21, and raw water W produced by a pure water production apparatus (not shown) is deaerated through the raw water supply pipe 23. The deaerated water supplied to the membrane module 1 and deaerated in the deaeration membrane module 1 is supplied to the gas dissolution module 2 via the deaerated water supply pipe 24. A vacuum pump 25 is connected to the gas phase chamber 22 through an exhaust pipe 26.

  The gas permeable membrane 20 is not particularly limited as long as it does not transmit water and allows gas to pass. For example, polypropylene, polydimethylsiloxane, polycarbonate-polydimethylsiloxane block copolymer, polyvinylphenol-polydimethylsiloxane. -Polysulfone block copolymers, polymer films such as poly (4-methylpentene-1), poly (2,6-dimethylphenylene oxide), polytetrafluoroethylene and the like. Also, the vacuum pump 25 is not particularly limited, but for example, a pump capable of sucking water vapor such as a water-sealed vacuum pump or a scroll pump having a water vapor removing function is preferable.

  As the raw water W, in general, pure water or ultrapure water purified to such an extent that an object to be cleaned can be cleaned to a required cleanliness is used. Further, in order to prepare a cleaning liquid by dissolving a specific gas, it is preferable to subject the raw water W to degassing treatment. If the degassing water is used, an amount of gas exceeding the saturation solubility is efficiently removed. It is also preferable in that it can be dissolved. The degree of deaeration is preferably 80% or more, and more preferably 90% or more. In addition, according to the objective which wash | cleans to-be-cleaned object, if the deaeration process of the raw | natural water W is not required, it is not necessary to perform a deaeration process.

  The gas dissolving membrane module 3 is partitioned into a liquid phase chamber 31 and a gas phase chamber 32 by a gas permeable membrane 30. A degassed water supply pipe 24 and a nozzle water supply pipe 36 are connected to the liquid phase chamber 31, and the degassed water degassed in the degassing membrane module 1 passes through the degassed water supply pipe 24. Gas dissolved water that is supplied to the dissolved membrane module 2 and in which a predetermined gas is dissolved in the gas dissolved membrane module 2 is supplied to the cleaning device 6 through the nozzle water supply pipe 36. A gas supply device 33 is connected to the gas phase chamber 32 via a gas supply pipe 34. A gas supply control valve 35 for adjusting the flow rate of the gas supplied from the gas supply device 33 to the gas phase chamber 32 is provided in the middle of the gas supply pipe 34. The gas can be pressurized and supplied to the gas dissolution membrane module 3 by adjusting the gas supply control valve 35 and increasing the flow rate of the gas supplied to the gas phase chamber 32. Further, the gas phase chamber 32 is provided with a pressure gauge 8A.

  The gas permeable membrane 30 is not particularly limited as long as it does not transmit water and allows gas to pass. For example, polypropylene, polydimethylsiloxane, polycarbonate-polydimethylsiloxane block copolymer, polyvinylphenol-polydimethylsiloxane. -Polysulfone block copolymers, polymer films such as poly (4-methylpentene-1), poly (2,6-dimethylphenylene oxide), polytetrafluoroethylene and the like.

  Examples of the gas supplied from the gas supply device 33 to the gas phase chamber 32 of the gas dissolution membrane module 3 include noble gases such as nitrogen gas, oxygen gas, carbon dioxide gas, hydrogen gas, ozone gas, clean air, and argon gas. The gas may be any one of these, or may be a mixed gas of two or more of these. When two or more kinds of gases are dissolved in the cleaning liquid, it is only necessary that any one of the gases exceeds the saturation solubility.

  In the present embodiment, in order to dissolve the gas in the liquid beyond the saturation solubility, the gas-dissolved membrane module 3 is used to pressurize and supply the gas to the gas phase chamber 32 of the gas-dissolved membrane module 3. Although the method of dissolving in the liquid in the chamber 31 is adopted, the method is not limited to this as long as the gas can be dissolved in the liquid exceeding the saturation solubility.

  A nozzle water supply pipe 36 extending from the liquid phase chamber 31 of the gas dissolution membrane module 3 is connected to a discharge nozzle 62 provided in the chamber 61 of the cleaning device 6. In the middle of the nozzle water supply pipe 36, a chemical supply device 5 for adding a chemical such as ammonia to the gas-dissolved water is connected via a chemical supply pipe 51, and in the middle of the chemical supply pipe 51, the nozzle water supply pipe A medicine supply control valve 52 for adjusting the amount of medicine supplied to 36 is provided.

  Examples of the chemical added to the gas-dissolved water by the chemical supply device 5 include alkali agents such as ammonia, sodium hydroxide, potassium hydroxide, and tetramethylammonium hydroxide, acids such as hydrogen fluoride, hydrogen chloride, and sulfuric acid, and chelates. Agents, surfactants, and the like, and any one of them may be used, or two or more of them may be added. In particular, by adding an alkaline agent such as ammonia and adjusting the pH of the cleaning liquid to 7 or more, preferably 9 to 14, the cleaning effect of fine particles and the like can be enhanced. In addition to using an alkaline agent for this pH adjustment, an alkaline gas may be used, but it is preferable to use ammonia from the viewpoint of easy handling and easy concentration control. In particular, it is possible to obtain a good cleaning effect by using a cleaning liquid prepared by adding ammonia at 1 mg / L or more, for example, about 1 to 200 mg / L, and adjusting the pH to 7 to 11. In addition, when the pH of this cleaning liquid is excessively high or the amount of ammonia added is excessively large, there is a possibility that damage to the object to be cleaned may occur, which is not preferable. Moreover, the addition of a chemical such as ammonia may be performed after the gas is dissolved in the raw water W or the deaerated water as shown in the present embodiment, or may be performed before the gas is dissolved.

  Further, a nozzle water supply control valve 37 for adjusting the flow rate of the cleaning liquid supplied to the discharge nozzle 62 and a pressure gauge 8B are provided in the middle of the nozzle water supply pipe 36. In the present embodiment, the chemical supply pipe 51, the pressure gauge 8B, and the nozzle water supply control valve 37 are provided in this order from the upstream side of the nozzle water supply pipe 36 to the nozzle water supply pipe 36.

  A nozzle water supply pipe 36 is connected to the discharge nozzle 62, and a carrier gas supply device 7 is connected via a carrier gas supply pipe 71. In the middle of the carrier gas supply pipe 71, a carrier gas supply control valve 72 for adjusting the supply amount of the carrier gas to the discharge nozzle 62 and a pressure gauge 8C are provided. As described above, the gas-dissolved water is supplied to the discharge nozzle 62 through the nozzle water supply pipe 36 and the carrier gas is supplied to the discharge nozzle 62 through the carrier gas supply pipe 71, whereby the gas-dissolved water and the carrier gas are cleaned. 9 is configured to be discharged from the discharge nozzle 62 toward the nozzle 9.

  Although not particularly shown in the present embodiment, a filter may be installed at an arbitrary location upstream of the discharge nozzle 62 in order to increase the cleanliness of the cleaning liquid.

  In order to prepare gas-dissolved water using the cleaning system 1 configured as described above and clean an object to be cleaned, first, raw water W (pure water or ultrapure water) is passed through the raw water supply pipe 23. While supplying to the liquid phase chamber 21 of the deaeration membrane module 2, the vacuum pump 25 is operated and the gas phase chamber 22 is pressure-reduced. As a result, the dissolved gas dissolved in the raw water W in the liquid phase chamber 21 passes through the gas permeable membrane 20 and is discharged out of the system via the gas phase chamber 22 and the exhaust pipe 26. Is degassed. Here, the gas phase chamber 22 is preferably decompressed to 10 kPa or less, particularly 5 kPa or less.

  Degassed water (degassed raw water W) degassed in the liquid phase chamber 21 of the degassing membrane module 2 is supplied to the liquid phase chamber 31 of the gas dissolving membrane module 3 via the degassed water supply pipe 24. Flows in. On the other hand, the dissolved gas is supplied from the gas supply device 33 to the gas phase chamber 32 of the gas dissolution membrane module 3 via the gas supply pipe 34. The amount of gas supplied to the gas phase chamber 32 is adjusted by the gas supply control valve 35, and the gas is pressurized and supplied to the gas dissolution membrane module 3 by increasing the gas supply amount to the gas phase chamber 32. The gas supplied to the gas phase chamber 32 passes through the gas permeable membrane 30, is supplied to the liquid phase chamber 31, and is dissolved in deaerated water. When the raw water W is deaerated water, the amount of dissolution may be calculated from the gas supply amount and the amount of water, or the concentration may be measured using a densitometer on the secondary side of the gas dissolution membrane module 3. Although it is good, it is easy to control by the value of the pressure gauge 8A for measuring the pressure in the gas phase chamber 32 of the gas-dissolving membrane module 3, and it is preferably used.

  Here, the multiple of the gas solubility with respect to the saturation solubility is referred to as saturation, for example, “saturation degree 1” if it is equal to the saturation solubility, “saturation degree 2” if it is twice the saturation solubility, saturation solubility. If it is three times the amount, it is referred to as “saturation degree 3”. When measuring the pressure in the gas phase chamber 32, the saturation of the gas dissolved water obtained when the value of the pressure gauge 8A is 0 MPa (≈1 atm) on the basis of the normal pressure state, the value of the pressure gauge 8A When the pressure is 0.1 MPa, the degree of saturation of the gas dissolved water is 2, and when the value of the pressure gauge 8A is 0.2 MPa, the degree of saturation of the gas dissolved water is 3, so the gas dissolved water is dissolved based on the value of the pressure gauge 8A. Water saturation can be adjusted.

  In the present embodiment, the dissolved amount of the dissolved gas in the gas-dissolved water is a state in which the saturated solubility under normal pressure at the liquid temperature of the gas-dissolved water is the first saturated solubility, and a predetermined pressure is applied while maintaining the liquid temperature. When the saturation solubility in the second saturation solubility is the second saturation solubility, 10 to 70% of the difference between the second saturation solubility and the first saturation solubility must be added to the first saturation solubility. More preferably, 20 to 60% of the difference from the first saturation solubility is added to the first saturation solubility. By controlling the amount of dissolved gas dissolved in the cleaning liquid in this way, a gas having a solubility higher than the saturation solubility at the liquid temperature of the cleaning liquid is dissolved in a state where a predetermined pressure is applied to the cleaning liquid used in high-pressure jet cleaning or two-fluid cleaning. When a cleaning liquid or a mixed fluid of cleaning liquid and gas is discharged from the cleaning fluid discharge nozzle as cleaning droplets toward the object to be cleaned, this supersaturated gas grows into bubbles under normal pressure. Or, before discharging the cleaning liquid or the mixed fluid of the cleaning liquid and gas from the cleaning fluid discharge nozzle as cleaning droplets toward the object to be cleaned, this supersaturated gas becomes fine bubbles in the cleaning liquid, and small droplets are formed. Many are generated. When these bubbles and cleaning droplets are ejected from the cleaning fluid discharge nozzle toward the object to be cleaned, in addition to the physical cleaning action that these bubbles and cleaning droplets collide with the surface of the object to be cleaned, the bubble scrub effect, bubble collision Because of the physicochemical cleaning action such as the impact force of the gas and the adsorption force at the gas-liquid interface, fine particles, organic substances, metals, etc. can be efficiently removed from the surface of the object to be cleaned, resulting in a high cleaning effect. be able to.

  On the other hand, when the dissolved amount of the dissolved gas in the gas-dissolved water is an amount obtained by adding an amount exceeding 70% of the difference between the second saturated solubility and the first saturated solubility to the first saturated solubility, In the process in which the added gas-dissolved water passes through the nozzle water supply control valve 37 and is depressurized, the diameter of bubbles generated becomes too large, and the cleaning effect is hindered. Further, when the dissolved amount of the dissolved gas in the gas-dissolved water is an amount obtained by adding less than 10% of the difference between the second saturated solubility and the first saturated solubility to the first saturated solubility, the gas-dissolved water or the chemical is added. Since the gas dissolved water passes through the nozzle water supply control valve 37 and is depressurized, bubbles are not sufficiently generated, so that a desired cleaning effect cannot be obtained.

  In addition, the ratio of the dissolved amount of the dissolved gas in the gas dissolved water with respect to the second saturation solubility based on the first saturation solubility is referred to as a supersaturation ratio. That is, the supersaturation ratio of the gas-dissolved water in which the dissolved gas of the first saturation solubility is dissolved is 0%, and the supersaturation ratio of the gas-dissolved water in which the dissolved gas of the second saturation solubility is dissolved is 100%. For example, the supersaturation ratio of the gas-dissolved water in which dissolved gas is dissolved by adding 60% of the difference between the second saturation solubility and the first saturation solubility to the first saturation solubility is 60%.

  The value of the pressure gauge 8A needs to be lower than the value of the pressure gauge 8B provided in the middle of the nozzle supply pipe 36. That is, the pressure P1 in the gas phase chamber 32 of the gas dissolution membrane module 3 measured by the pressure gauge 8A and the nozzle water supply pressure P2 of the gas dissolution water measured by the pressure gauge 8B have a relationship of P1 <P2. Is required. This is to prevent bubbles from being generated from the gas-dissolved water in the process in which the gas-dissolved water is supplied to the discharge nozzle 62 through the nozzle supply pipe 36. Therefore, in order to increase the degree of saturation of the gas-dissolved water. It is necessary to increase this water pressure. The value of the nozzle water supply pressure P2 is not particularly limited, but it is usually preferable to set the value of the pressure gauge 8B to about 0.1 to 1.0 MPa, based on the normal pressure state, and 0.2 to 0.00. More preferably, the pressure is about 6 MPa.

  The gas dissolved water obtained by dissolving the desired gas in the raw water W by the gas dissolving membrane module 3 is adjusted in flow rate by the nozzle water supply amount adjusting valve 37 and supplied to the discharge nozzle 62 through the nozzle water supply pipe 36.

  When a drug is added to the gas-dissolved water, a drug whose supply amount is adjusted by the drug supply control valve 52 is injected into the gas-dissolved water through the drug supply pipe 51. In the present embodiment, as shown in FIG. 1, the drug injection point is the secondary side of the gas dissolution membrane module 3, but the present invention is not limited to this. For example, the drug injection point is the gas dissolution membrane module 3 may be the primary side.

  The cleaning liquid (gas-dissolved water or gas-dissolved water to which a chemical is added) is in a state where a predetermined pressure is applied until it reaches the pressure release point on the primary side of the discharge nozzle, that is, the nozzle water supply amount adjustment valve 37. However, the secondary side of the nozzle water supply amount adjustment valve 37 is opened to the atmosphere, and the gas dissolved in the cleaning solution at a saturation solubility or higher starts to bubble. Here, if the time required for the cleaning liquid to pass through the nozzle water supply amount adjustment valve 37 and be introduced into the discharge nozzle 62 becomes longer, the association of bubbles proceeds and the fine bubbles effective for cleaning may disappear. . Therefore, the time required for the cleaning liquid to pass through the nozzle water supply amount adjustment valve 37 and be introduced into the discharge nozzle 62 is preferably less than 7 seconds, and more preferably about 0.5 to 3 seconds.

  In the discharge nozzle 62, the cleaning liquid (gas-dissolved water or gas-dissolved water to which a chemical is added) and the carrier gas are mixed. The carrier gas is supplied to the discharge nozzle 62 through the carrier gas supply pipe 71 after the flow rate is controlled by the carrier gas supply control valve 72 and the supply pressure is controlled based on the value of the pressure gauge 8C. The value of the carrier gas supply pressure V3 is not particularly limited, but normally, the value of the pressure gauge 8C is preferably about 0.1 to 1.0 MPa based on the normal pressure state, and is preferably 0.2 to 0. More preferably, about 6 MPa.

  Examples of the carrier gas include nitrogen gas, oxygen gas, carbon dioxide gas, hydrogen gas, ozone gas, clean air, and rare gas such as argon gas, and any one of these may be used. Two or more mixed gases may be used.

  The cleaning fluid that has become the mixed fluid of the carrier gas and the cleaning liquid at the discharge nozzle 62 is discharged toward the object 9 to be cleaned, and fine bubbles and cleaning droplets generated from the gas that has been dissolved in the cleaning liquid at a saturation solubility or higher are generated. Efficiently removes fine particles, organic matter, metals, etc. from the surface of the object to be cleaned by colliding with the surface of the object to be cleaned and by physicochemical cleaning such as bubble scrubbing effect, bubble collision impact force, gas-liquid interface adsorption force, etc. By removing, the surface of the article 9 to be cleaned is cleaned. At this time, the surface of the article 9 to be cleaned can be more effectively cleaned by rotating the turntable 63 preferably at about 10 to 500 rpm, more preferably about 100 to 300 rpm.

  Normally, the temperature of the cleaning liquid in the high-pressure jet cleaning or the two-fluid cleaning is set in a range of 10 to 90 ° C. However, according to the cleaning method according to the present embodiment, excellent cleaning is achieved even with a normal temperature cleaning liquid. Since the effect can be obtained, the cleaning liquid temperature may be normal temperature. The cleaning time is usually about 3 to 60 seconds, although it varies depending on the degree of saturation of the used cleaning liquid, the presence or absence of addition of chemicals, and other cleaning conditions.

In the present embodiment, as the discharge conditions for the cleaning liquid and the carrier gas discharged from the discharge nozzle 62, for example, the following conditions can be employed.
Cleaning liquid supply amount: 0.05 to 0.5 L / min
Nozzle hydraulic pressure: 0.05 to 0.5 MPa
Carrier gas pressure: 0.1-0.6 MPa

In this embodiment, two-fluid cleaning is adopted, but high-pressure jet cleaning can be adopted instead of two-fluid cleaning. When performing high-pressure jet cleaning, for example, the following conditions can be adopted as discharge conditions for the cleaning liquid discharged from the discharge nozzle 62.
Cleaning liquid supply amount: 0.05 to 0.5 L / min
Nozzle hydraulic pressure: 5-10MPa

  There is no particular limitation on the object 9 to be cleaned in the cleaning method according to the present embodiment, but in view of the high cleaning effect of the cleaning method according to the present embodiment, a silicon wafer for semiconductors, glass for flat panel displays. It is suitable for cleaning electronic materials (electronic components and electronic members) that require high cleanliness, such as substrates and quartz substrates for photomasks.

  EXAMPLES Hereinafter, although an Example and a comparative example demonstrate this invention in detail, this invention is not limited at all by these Examples. In the following Examples and Comparative Examples, a 6-inch wafer contaminated with an alumina slurry was treated as an object to be cleaned after being treated with ozone water to make the surface hydrophilic. The number of fine particles of 1.0 μm or more on the wafer surface after contamination was about 200 / wafer.

[Example 1]
In the cleaning system 1 shown in FIG. 1, the object 9 to be cleaned was set on the turntable 63 and installed in the chamber 61 and cleaned using gas-dissolved water. As the gas-dissolved water, nitrogen gas-dissolved water in which nitrogen gas was dissolved in the ultrapure water by the gas-dissolving membrane module 3 so that the supersaturation ratio was 60% (saturation degree 4) was used. Other cleaning conditions were as follows.
Discharge nozzle: Asahi Sunac Co., Ltd. two-fluid nozzle Gas dissolved water supply to the nozzle: 0.1 L / min
Gas solution water temperature: 24 ° C
Nozzle feed water pressure (V2): 0.5 MPa
Carrier gas supply pressure (V3): 0.4 MPa
Time required from the pressure release point to the nozzle: 2 seconds Number of turntable rotation during cleaning: 100 rpm
Cleaning time: 10 seconds Drying method: Nitrogen gas blow Rotary table rotation speed during drying: 1500 rpm
Drying time: 30 seconds

  When the number of fine particles of 1.0 μm or more on the surface of the object to be cleaned after washing was measured, the removal rate of fine particles was 88%.

[Example 2]
In the cleaning system 1 shown in FIG. 1, the object 9 to be cleaned was set on the turntable 63 and installed in the chamber 61 and cleaned using gas-dissolved water. When the same conditions as in Example 1 were used except that the time required from the pressure release point to the nozzle was 3 seconds, the removal rate of fine particles after washing was 85%.

Example 3
In the cleaning system 1 shown in FIG. 1, the object 9 to be cleaned was set on the turntable 63 and installed in the chamber 61 and cleaned using gas-dissolved water. When the same conditions as in Example 1 were used except that the amount of dissolved gas was 20%, the removal rate of fine particles after washing was 82%.

Example 4
In the cleaning system 1 shown in FIG. 1, the object 9 to be cleaned was set on the turntable 63 and installed in the chamber 61 and cleaned using gas-dissolved water. When the conditions were the same as in Example 1 except that the amount of dissolved gas was 40%, the removal rate of fine particles after cleaning was 84%.

[Comparative Example 1]
In the cleaning system 1 shown in FIG. 1, the object 9 to be cleaned was set on the turntable 63 and installed in the chamber 61 and cleaned using gas-dissolved water. When the conditions were the same as in Example 1 except that the amount of dissolved gas was 0% (saturation level 1), the removal rate of fine particles after cleaning was 74%.

[Comparative Example 2]
In the cleaning system 1 shown in FIG. 1, the object 9 to be cleaned was set on the turntable 63 and installed in the chamber 61 and cleaned using gas-dissolved water. When the conditions were the same as in Example 1 except that the amount of dissolved gas was 100% (saturation level 6), the removal rate of fine particles after washing was 80%.

[Comparative Example 3]
In the cleaning system 1 shown in FIG. 1, the object 9 to be cleaned was set on the turntable 63 and installed in the chamber 61 and cleaned using gas-dissolved water. When the conditions were the same as in Example 1 except that the amount of dissolved gas was 5%, the removal rate of fine particles after cleaning was 78%.

[Comparative Example 4]
In the cleaning system 1 shown in FIG. 1, the object 9 to be cleaned was set on the turntable 63 and installed in the chamber 61 and cleaned using gas-dissolved water. When the same conditions as in Example 1 were used except that the dissolved gas amount was 80%, the removal rate of fine particles after washing was 80%.

Table 1 shows the results of Examples 1, 3 and 4 and Comparative Examples 1 to 4 described above.

  According to the above, it was confirmed that the removal rate of fine particles after cleaning is higher when the dissolved gas amount is a predetermined amount (when the supersaturation ratio is in the range of 10 to 70%). In addition, it is confirmed that the removal rate of fine particles after cleaning increases as the time required for gas dissolved water to pass through the nozzle water supply amount adjustment valve 37 (pressure release point) and be introduced into the discharge nozzle 62 is shorter. It was done.

  The present invention is useful as a cleaning method for removing fine particles, organic substances, metals, and the like from the surface of electronic materials such as silicon wafers for semiconductors and glass substrates for flat panel displays.

DESCRIPTION OF SYMBOLS 1 ... Cleaning system 2 ... Deaeration membrane module 20 ... Gas permeable membrane 21 ... Liquid phase chamber 22 ... Gas phase chamber 23 ... Raw water supply pipe 24 ... Deaerated water supply pipe 25 ... Vacuum pump 26 ... Exhaust pipe 3 ... Gas dissolution membrane Module 30 ... Gas permeable membrane 31 ... Liquid phase chamber 32 ... Gas phase chamber 33 ... Gas supply device 34 ... Gas supply pipe 35 ... Gas supply control valve 36 ... Nozzle water supply pipe 37 ... Nozzle water supply amount control valve 5 ... Drug supply device 51 ... Drug supply pipe 52 ... Drug supply control valve 6 ... Cleaning device 61 ... Chamber 62 ... Discharge nozzle 63 ... Rotary table 7 ... Carrier gas supply apparatus 71 ... Carrier gas supply pipe 72 ... Carrier gas supply control valve 8A ... Pressure gauge 8B ... Pressure gauge 8C ... Pressure gauge 9 ... Object to be cleaned

Claims (8)

A cleaning method for discharging a cleaning liquid or a mixed fluid of a cleaning liquid and a gas toward an object to be cleaned from a cleaning fluid discharge nozzle, and performing high-pressure jet cleaning or two-fluid cleaning on the object to be cleaned,
The cleaning liquid introduced into the fluid discharge nozzle contains dissolved gas,
The dissolved gas is dissolved in the cleaning liquid by applying a predetermined pressure,
The amount of the dissolved gas dissolved in the cleaning liquid is defined as the first solubility of the saturation solubility at the liquid temperature of the cleaning liquid, and the saturation solubility in a state where the predetermined pressure is applied while the liquid temperature of the cleaning liquid is maintained. A cleaning method, wherein the saturation solubility is obtained by adding 10 to 70% of the difference between the second saturation solubility and the first saturation solubility to the first saturation solubility.   The dissolved gas may be any one gas or a mixed gas of two or more of nitrogen gas, oxygen gas, carbon dioxide gas, hydrogen gas, ozone gas, clean air, and rare gas. The cleaning method according to 1.   The cleaning method according to claim 1 or 2, wherein the predetermined pressure is a pressure higher by 0.1 to 1.0 MPa than a normal pressure.   The cleaning method according to claim 1, wherein the liquid that dissolves the dissolved gas is pure water or ultrapure water.   The cleaning method according to claim 1, wherein the liquid that dissolves the dissolved gas is degassed.   The cleaning method according to claim 1, wherein the cleaning liquid contains any one or two or more chemicals selected from alkalis, acids, chelating agents, and surfactants. .   The said washing | cleaning liquid exists in the state to which the said predetermined pressure was applied until it reached | attained the pressure release point in the primary side of the said fluid discharge nozzle, It is any one of Claims 1-6 characterized by the above-mentioned. Cleaning method.   The cleaning method according to claim 7, wherein a time required for the cleaning liquid to pass through the pressure release point and be introduced into the fluid discharge nozzle is less than 7 seconds.

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