JP2002172366A - Method and apparatus for wet cleaning of substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformize and stabilize cleaning treatment and reduce the consumption of chemicals for preparing a cleaning solution in the wet cleaning of a substrate by etching using the cleaning solution in which hydrofluoric acid as an effective component is dissolved in water. SOLUTION: In a substrate cleaning apparatus 10, a cleaning tank 12 is installed in a cleaning draft 11, and a thermometer 13 is set in the vicinity of the upper end part of the cleaning tank. A humidifier 14 and an air conditioner 15 are installed right above the cleaning tank, a dust removing filter 16 is connected to the air inflow side of the air conditioner, the thermometer 13 is connected to the humidifier 14, and the air inflow side of the filter is connected to a blower. An automatic damper 18 is fitted to an exhaust duct 17 connected to the cleaning draft, an anemometer 19 is set downstream from the damper 18, and the anemometer is connected to a driving mechanism for adjusting the opening of the damper. In a substrate cleaning process, clean air the relative humidity and temperature of which are controlled is supplied vertically downward toward the surface of the cleaning solution in the cleaning tank, and air in the draft is discharged in a displacement within a prescribed range.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for wet cleaning a substrate, and more particularly to a method and an apparatus for immersing a silicon substrate having a silicon oxide film on its surface or a glass substrate in a cleaning liquid for cleaning. It is.

[0002]

2. Description of the Related Art Conventionally, semiconductors and LCDs (liquid crystal display devices)
In the manufacturing process of the above, for cleaning the semiconductor substrate and the glass substrate, a mixed aqueous solution of ammonium fluoride and hydrofluoric acid,
An aqueous solution of ammonium fluoride or an aqueous solution of hydrofluoric acid is used as a cleaning liquid. The cleaning of the semiconductor substrate is mainly performed to remove the oxide film (thermal oxide film or natural oxide film) formed on the surface by etching, and the cleaning of the glass substrate is also performed by removing the surface layer of the substrate by etching. It is done to do. In addition,
The ammonium fluoride aqueous solution is an arbitrary mixture of hydrofluoric acid and ammonia, is dissolved in water in the form of NH4F, and may contain a surfactant.

In the field of the above-mentioned semiconductor and LCD manufacturing technologies,
In order to achieve lighter, smaller, and lower power consumption products
In order to further increase the degree of integration, a technology capable of finer processing is required. Under such circumstances, a higher-precision cleaning process is also desired in the above-described substrate cleaning technology using a cleaning liquid.

Conventionally, in the wet cleaning technique for semiconductor substrates, generally, a cleaning liquid is stored in a cleaning tank provided in a cleaning draft, and a large number of semiconductor substrates are stored in a container called a wafer cassette, and this container is immersed in the cleaning liquid. Then, cleaning is performed while simply flowing clean air into the cleaning draft without performing special control.

For this reason, as shown in FIG. 3, the concentration of hydrofluoric acid (HF) in the cleaning liquid increases as the cleaning time elapses. FIG. 3 is a graph showing the relationship between the elapsed time (cleaning time) from the time when the cleaning liquid was used for cleaning and the concentration of hydrofluoric acid in the cleaning liquid. As a result, as shown in FIG. 4, the etching rate of the silicon oxide film or the surface layer of the glass substrate increases with time, and the change in the concentration has a large unevenness, so that uniform and stable cleaning cannot be performed. There has been a problem that it is difficult to improve the yield of semiconductor substrates and substrates for liquid crystal display devices.

The causes of the increase in the concentration of hydrofluoric acid in each of the cleaning liquids with the elapse of the cleaning time are as follows: (1) Moisture evaporated from the cleaning liquid is discharged out of the cleaning draft along with clean air; 2) In the above-mentioned aqueous solution of ammonium fluoride, ammonium fluoride (NH4F) is dissociated into ammonium hydroxide and hydrofluoric acid, and this ammonium hydroxide becomes ammonia gas, which is also removed from the cleaning draft together with clean air. To be discharged to

Conventionally, therefore, a method has been employed in which the cleaning solution is frequently replaced to suppress an increase in the active ingredient concentration (including the concentration unevenness) in the cleaning solution. However, in such a method, a very large amount of cleaning liquid is used.
In particular, the cleaning solution containing ammonium fluoride is 40 wt.
% Because it is used in a high concentration state of around%
There is a problem that the amount of chemical consumed per liquid exchange is increased as compared with other cleaning liquids used at a concentration of about one level.

When the hydrofluoric acid-based cleaning liquid (hydrofluoric acid-based cleaning liquid) has been used, a waste liquid treatment (drainage treatment) by a process as shown in FIG. 5 is required. In this case, not only a large amount of resources, that is, a wastewater treatment agent, is consumed, but also a large amount of waste (drainage and sludge) is generated as is apparent from the material balance diagram of FIG. FIG. 5 is a flow sheet (processing flow of ammonium fluoride waste liquid from a semiconductor manufacturing process) showing a waste liquid processing step of a used cleaning liquid. FIG. 6 is an explanatory diagram showing a material balance relating to the waste liquid treatment step of FIG.

In recent years, global environmental problems have become a global concern, and the influence of the manufacturing process of substrates such as semiconductors and LCDs on the environment has become a problem in recent years. It is not enough to reduce washing costs of resources, and it is necessary to save resources, reduce the amount of waste generated, and purify the environment.
There is a strong social demand for environmental protection.

For this reason, the temperature, humidity, clean air volume and the like are controlled as a cleaning apparatus which can maintain the chemical composition of the cleaning liquid in the cleaning tank within a predetermined range without frequently changing the cleaning liquid. (Japanese Patent Application Laid-Open No. Hei 9-22891) has been proposed in which a cleaning tank is installed in an atmosphere that has been heated. However, in this cleaning apparatus, although the humidified air curtain is used, since the flow of the clean air is horizontal, not only is it difficult to maintain the cleanness of the substrate to be cleaned, but also it is necessary to insert and remove the substrate to be cleaned. At that time, the flow of air must be interrupted, which causes a problem that the operation is troublesome.

[0011]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and it is an object of the present invention to provide a wet cleaning technique for a substrate using a cleaning solution in which hydrofluoric acid is dissolved in water as an active ingredient. An object of the present invention is to make the treatment uniform and stable, and to reduce the environmental burden associated with the use of the cleaning liquid, that is, to reduce the consumption of cleaning chemicals, reduce the amount of waste generated, and suppress environmental pollution.

[0012]

In a wet cleaning method for a substrate according to the present invention, a cleaning liquid obtained by dissolving an active ingredient in water is stored in a cleaning tank provided in a cleaning draft, and the substrate to be cleaned is added to the cleaning liquid. In the method of immersing and cleaning while flowing clean air in the cleaning draft, the clean air whose relative humidity is controlled within a predetermined range by humidification is supplied vertically downward toward the cleaning liquid level of the cleaning tank, The substrate to be cleaned is cleaned while exhausting the air in the cleaning draft with a displacement within a predetermined range.

In the above-mentioned cleaning method, the relative humidity is set at 40% to 5%.
It is desirable to supply clean air whose temperature is controlled to room temperature in the range of 0%, whereby the effect of the present invention becomes more remarkable. Also, by controlling the pressure inside the cleaning draft higher than the outside atmospheric pressure,
It is preferable to prevent the atmosphere outside the cleaning draft from entering the cleaning draft. By doing so, the cleanness of the clean air in the cleaning draft is maintained, and the flowing state of the clean air and the temperature and humidity are stabilized, so that more stable wet cleaning can be continued.

Further, in the above-mentioned cleaning method, by using at least one of ammonium fluoride and hydrofluoric acid dissolved in water as a cleaning liquid, a silicon oxide film formed on the surface of the silicon substrate or a glass substrate is removed. The surface layer can be efficiently removed by etching.

Further, in the wet cleaning apparatus for a substrate according to the present invention, a cleaning liquid obtained by dissolving an active ingredient in water is stored in a cleaning tank provided in a cleaning draft, and the substrate to be cleaned is immersed in the cleaning liquid. In a device that cleans while flowing clean air into the cleaning draft, clean air supply means that supplies clean air vertically into the cleaning draft toward the cleaning liquid level in the cleaning tank, and steam or mist A humidifier that supplies water droplets and maintains the relative humidity of the clean air in the cleaning draft within a predetermined range, a hygrometer disposed near the cleaning liquid level of the cleaning tank and connected to the humidifier, and a cleaning draft. An exhaust pipe for exhausting the air inside, and an exhaust amount control means provided in the exhaust pipe, and a humidity measurement value by a hygrometer is fed back to the humidifier, and The supply amount of vapor or mist water droplets is controlled within a predetermined range, characterized in that so as to exhaust the exhaust amount within a predetermined range of air in the cleaning draft by the exhaust amount control means.

In the above wet cleaning apparatus, the clean air supply means comprises a blower and a dust filter connected to the air discharge side of the blower, and the humidifier applies water vapor or mist water droplets to the cleaning liquid level of the cleaning tank. The exhaust volume control means consists of a damper that can automatically adjust the opening and an air flow meter or barometer provided in the exhaust pipe, and these instruments are connected to the damper. It is preferable that a communication is made, and the measured value of the meter is fed back to the damper to control the opening thereof.

Furthermore, in the above wet cleaning apparatus, a humidifier for supplying steam or mist-like water drops whose temperature is controlled within a predetermined range is provided, and a clean humidifier supplied vertically downward to the cleaning liquid level is provided. It is preferable to provide an air conditioner for controlling the temperature of air within a predetermined range.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic explanatory view showing a substrate cleaning apparatus (wet cleaning apparatus) and a substrate cleaning method using the apparatus. FIG. 2 is a graph showing a comparison between the etching rate of the silicon oxide film on the surface of the semiconductor substrate in the cleaning method of the present invention and the conventional cleaning method.

The substrate cleaning apparatus 10 is configured as follows. A cleaning tank 12 is provided below a cleaning draft (draft chamber) 11 having an opening / closing door (not shown), and a hygrometer 13 is installed near the upper end of the cleaning tank 12 (near the liquid level of the cleaning liquid 31). A humidifier 14 and an air conditioner 15 are provided directly above the washing tank 12, a dust filter 16 is connected to the air inflow side of the air conditioner 15, and the hygrometer 13 is connected to the humidifier 14.
Contact The air inlet side of the dust filter 16 is connected to the air discharge side of the blower via an air supply duct (not shown). In the cleaning tank 12, it is desirable to provide a temperature control means (not shown) for suppressing the temperature rise of the cleaning liquid with the elapse of the cleaning time and maintaining the temperature at a normal temperature.

The cleaning tank 1 on the peripheral wall 11a of the cleaning draft 11
2. An exhaust duct 17 is connected to the vicinity of the upper end, and an automatic damper 18 is provided in the exhaust duct 17, and an anemometer 19 (or a manometer) is provided on the downstream side. The anemometer 19 is communicated to the drive mechanism of the automatic damper 18. The anemometer 19 may be provided on the upstream side of the automatic damper 18,
It can also be provided in the cleaning draft 11.

In FIG. 1, a cleaning tank 1 is provided in a cleaning draft 11.
Although only 2 (etching tank) is shown, a rinsing tank and a drying tank (not shown) can be arranged in the cleaning draft 11 adjacent thereto. In this case, as the rinsing tank, one in which the substrate is immersed in, for example, ion-exchanged water,
As the drying tank, for example, a drying tank that sprays IPA (isopropyl alcohol) onto the substrate surface, and then blows the air with clean air to dry the substrate is used. The cleaning draft 11, the rinsing tank, and the drying tank may be arranged in this order and individually in each of the compartments partitioned by the partition walls, and the adjacent compartments may communicate with each other by opening an opening / closing door provided on the partition wall. Good.

Next, an example of a method for cleaning a silicon substrate by the substrate cleaning apparatus 10 will be described. A predetermined amount of a room temperature cleaning solution 31 prepared by dissolving ammonium fluoride and hydrofluoric acid at a predetermined concentration in water is charged into the cleaning tank 12. Open the auto damper 18 at an appropriate opening,
Power on the blower, humidifier 14 and air conditioner 15
To In order to suppress the evaporation of water from the cleaning liquid 31, the atmosphere in the cleaning draft 11 needs to be at a relative humidity at which the water is difficult to dry. For this reason, the humidifier 14 is used to set the relative humidity to a target value (preferably, a saturated humidity). Near humidity)
Set. Further, in order to control the atmosphere in the cleaning draft 11 to a predetermined temperature, a target value of the temperature is set by the air conditioner 15 and the amount of air exhausted in the cleaning draft 11 (the amount of exhaust air per unit time) is controlled. The target value of the displacement is set for the drive mechanism of the automatic damper 18.

Many silicon substrates (silicon wafers)
Are stored in a wafer cassette in a vertical direction, parallel to each other, and with an appropriate gap therebetween, and the entire container is immersed in a cleaning liquid 31 to start cleaning. In this cleaning step, the silicon substrate is cleaned by removing a natural oxide film formed on the surface by etching.

In this cleaning step, the air from the blower (the temperature is almost normal temperature and the pressure is higher than the atmospheric pressure) is passed through the dust removing filter 16, the air conditioner 15 and the humidifier 14, and the cleaning solution 31 The liquid is supplied vertically downward toward substantially the entire liquid surface. In this case, the air from the blower is highly purified by the dust filter 16 and the air conditioner 1
5, the temperature is controlled to a predetermined range (usually, approximately normal temperature), and the relative humidity is controlled to a predetermined range by mist-like pure water droplets sprayed from the humidifier 14. The clean air that has come into contact with the cleaning liquid level is exhausted to the outside at a predetermined flow rate through the auto damper 18.

As described above, in the above-described cleaning step, the clean air in a humidified state in which the pressure is higher than the atmospheric pressure and is controlled to a predetermined temperature and a predetermined relative humidity is applied to substantially the entire surface of the cleaning liquid 31 in the cleaning tank 12. It is supplied vertically downward. Therefore, as compared with the case where clean air flows in parallel to the cleaning liquid surface, the function of suppressing evaporation of water from the cleaning liquid is greatly improved, and the function of replacing the cleaning liquid surface with air is enhanced. In addition, when handling the wafer cassette containing the silicon wafer, there is an advantage that the air in the gap between the wafers is more efficiently replaced by clean air.

In the above-mentioned cleaning step, the atmospheric pressure outside the cleaning draft 11 can be prevented from entering the cleaning draft by controlling the pressure inside the cleaning draft 11 to be higher than the atmospheric pressure outside. By doing so, there is no problem that the clean air in the cleaning draft is contaminated by the invading outside air, and the clean air flowing state and the temperature and humidity in the cleaning draft fluctuate, and more stable wet cleaning is continued. be able to.

Examples and Comparative Examples In Examples of the present invention, a silicon wafer was cleaned by the above-described cleaning method using the cleaning apparatus of FIG. In the comparative example, FIG.
The silicon wafer was cleaned in the same manner as in the example except that the air conditioner 15 and the humidifier 14 were not used in the cleaning device and the opening degree of the auto damper 18 was fixed. Figure 2 shows the results.
Shown in

As apparent from FIG. 2, in the embodiment, the rate of increase of the etch rate with respect to the elapsed time from the start of cleaning is low, and increases at a substantially constant rate. For this reason,
Even when the same cleaning solution was used for a long time, there was no need to change the solution.

On the other hand, in the comparative example, the rate of increase in the etch rate with respect to the elapsed time from the start of cleaning was higher than that in the example, and the change in the increase was uneven. However, after the liquid exchange, the etch rate was increased by short-time washing, and eventually, the etch rate became higher than that in the example in which the liquid exchange was not performed.

In the cleaning apparatus shown in FIG. 1, a humidifier using ultrasonic waves may be provided, or steam from boiling water may be supplied into the cleaning draft to humidify. In addition, the operation of supplying the clean air with the controlled temperature and humidity at a predetermined flow rate as described above includes ammonium fluoride, hydrofluoric acid,
It can also be effectively employed when replenishing various components such as aqueous ammonia, water, and surfactant to the cleaning solution.

The methods for measuring the concentration of the active ingredient and water in the cleaning solution include (1) a method for measuring the absorbance of light having a predetermined wavelength, (2) a method for measuring an infrared / ultraviolet absorption spectrum, and ( 3) a device for measuring the refractive index, specific gravity, light transmittance, conductivity, etc., (4) a device using a Karl Fischer moisture concentration meter, (5) a device using liquid (ion) chromatography, and the like can be used.

By using the above-described cleaning method, as shown in FIG. 2, the etching rate of the cleaning solution in which at least hydrofluoric acid is dissolved in water as an active ingredient with the lapse of cleaning time, that is, the change and unevenness of the cleaning effect. Can be greatly reduced. In addition, since the uniformity and stabilization of the cleaning with the cleaning liquid are realized, the chemicals required for reducing the frequency of liquid replacement (extending the cleaning liquid life) and for treating the waste liquid of the cleaning liquid (drainage treatment) are provided. A significant reduction in volume is possible. Further, there is an effect that the amount of generated waste, that is, sludge and wastewater (sewage) is reduced by the reduction in the amount of the chemical.

In the cleaning method according to the present invention, FIG.
As shown in FIG. 2, a constant linear relationship is observed between the elapsed time from the start of cleaning and the etch rate, and the etch rate at the start of cleaning (the value on the vertical axis when the elapsed time is zero in FIG. 2) is shown in FIG. The etch rate is determined by the concentration of hydrofluoric acid in the cleaning solution at the start of the cleaning, and the etch rate after the start of the cleaning is automatically determined by the elapsed time from the start of the cleaning.

Therefore, the etch rate can be easily estimated by knowing the hydrofluoric acid concentration of the cleaning solution at the start of cleaning and the elapsed time. In addition, cleaning with high reproducibility is possible, and there is an effect that cleaning can be performed with a uniform and constant etching amount. Conversely, by setting the required etching amount, the required etching time (the elapsed time) can be easily obtained. Further, by formulating the above linear relationship into a mathematical expression, the required etching time or the concentration of hydrofluoric acid in the cleaning liquid to be prepared can be more easily obtained.

Japanese Patent Application Laid-Open No. 9-22891 (title of invention: wet cleaning process apparatus and method) discloses an apparatus for "etching and cleaning" an oxide film on a silicon wafer surface. In this system, a cleaning tank storing a chemical solution is installed in an atmosphere where the temperature, humidity, and clean air flow rate are controlled, and clean air whose relative humidity is controlled to 70% or more is supplied above the cleaning liquid level of the cleaning tank. The wafer is cleaned while flowing horizontally.

However, in the above-described apparatus, if the wafer cassette is pulled out of the cleaning tank after the cleaning and the clean air is continuously passed through, for example, while being conveyed to the next water cleaning tank, the wafer cassette is discharged onto the wafer surface. Since the air is blown vertically and turbulence of clean air is generated on the wafer surface, there is a problem that so-called particles (foreign matter) adhere to the cleaned wafer surface. Eliminating this inconvenience involves the necessity of stopping the supply of clean air during the transfer of the wafer cassette.

On the other hand, in the cleaning method / apparatus of the present invention,
The substrate is cleaned while supplying clean air from above the cleaning tank to the cleaning liquid surface in the vertical direction. Therefore, when the wafer cassette is transported, the clean air flows in parallel to the wafer surface, so that there is almost no possibility of the generation of the particles. Therefore, it is possible to carry the wafer cassette while keeping the clean air flowing.

[0038]

According to the wet cleaning method of the first aspect,
The cleaning process can be made uniform, a high-quality cleaning product can be stably obtained, and the frequency of replacement of the cleaning solution is reduced. As a result, the consumption of the cleaning liquid preparation chemicals is reduced, and the waste liquid discharge amount of the used cleaning liquid is reduced, so that the burden of the waste liquid treatment is reduced, and the consumption of the chemicals for the waste liquid treatment is reduced, thereby conserving resources. Is achieved, and the amount of sludge and wastewater generated during waste liquid treatment is significantly reduced.

According to the wet cleaning method of the second aspect, in the cleaning step, the effect of reducing the amount of evaporation and loss of water from the cleaning liquid is enhanced, and the amount of evaporation is controlled within a predetermined range. 2. The relationship between the used time and the concentration of the active ingredient in the washing solution becomes stable and linear.
The effect of the invention of (1) becomes more remarkable.

In the wet cleaning method according to the third aspect, a cleaning solution obtained by dissolving at least one of ammonium fluoride and hydrofluoric acid in water is used, and the silicon oxide film formed on the surface of the silicon substrate is etched. Since the cleaning process is performed, the cleaning process is uniform, and the relationship between the cleaning time and the etching amount becomes linear. Therefore, the cleaning process with high reproducibility is performed, and the etching amount can be accurately controlled. Becomes

According to the wet cleaning apparatus of the fourth aspect, the cleaning method of the first aspect can be accurately performed.
Further, according to the wet cleaning apparatus of the sixth aspect, the first aspect of the present invention is the first aspect.
The cleaning method according to the above can be performed more accurately and efficiently. Further, according to the wet cleaning apparatus of the seventh aspect, the cleaning method of the first aspect can be performed more accurately and stably.

[Brief description of the drawings]

FIG. 1 is a schematic explanatory view showing a structure of a wet cleaning apparatus according to an embodiment of the present invention and a method for cleaning a substrate using the wet cleaning apparatus.

FIG. 2 is a graph showing a comparison between an etching rate of a silicon oxide film on the surface of a semiconductor substrate in a cleaning method of the present invention and a conventional cleaning method.

FIG. 3 relates to a problem of a conventional cleaning method, and an elapsed time (cleaning time) from a time when a cleaning liquid is used for cleaning.
4 is a graph showing a relationship between the cleaning solution and the concentration of hydrofluoric acid in the cleaning solution.

FIG. 4 is a graph showing the relationship between the elapse of the cleaning time and the etch rate of the semiconductor substrate when the cleaning liquid described with reference to FIG. 3 is used.

FIG. 5 relates to the problem of the conventional cleaning method, and is a flow sheet showing a waste liquid processing step of a used cleaning liquid, that is, a processing flow of ammonium fluoride waste liquid from a semiconductor manufacturing process.

FIG. 6 is an explanatory diagram showing a material balance relating to the waste liquid treatment step of FIG. 5;

[Explanation of symbols]

Reference Signs List 10: substrate cleaning device, 11: cleaning draft (draft chamber), 11a: peripheral wall, 12: cleaning tank, 13: hygrometer, 14: humidifier, 15: air conditioner, 16: dust filter, 17: exhaust duct, 18 ... auto damper, 19 ... anemometer, 31 ... cleaning liquid.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 21/306 H01L 21/306 J

Claims (6)

[Claims] 1. A washing solution comprising an active ingredient dissolved in water,
In a method of storing in a cleaning tank provided in a cleaning draft, immersing a substrate to be cleaned in the cleaning liquid, and cleaning while flowing clean air in the cleaning draft, clean air whose relative humidity is controlled within a predetermined range by humidification is used. Wet cleaning of a substrate, wherein the substrate to be cleaned is cleaned while supplying air downward in a vertical direction toward a cleaning liquid level of a cleaning tank and exhausting air in a cleaning draft within a predetermined range. Method. 2. The method according to claim 1, wherein clean air is supplied at a relative humidity in the range of 40% to 50% and at a normal temperature. 3. The method for wet cleaning a substrate according to claim 1, wherein the cleaning liquid is a solution obtained by dissolving at least one of ammonium fluoride and hydrofluoric acid in water. 4. A washing solution obtained by dissolving an active ingredient in water,
In an apparatus that stores the cleaning target in a cleaning tank provided in the cleaning draft, immerses the substrate to be cleaned in the cleaning liquid, and flows clean air into the cleaning draft, the clean air flows into the cleaning tank to the cleaning liquid level of the cleaning tank. A clean air supply means for supplying water downward or vertically into the cleaning draft, and a humidifier for maintaining the relative humidity of the clean air in the cleaning draft within a predetermined range; A hygrometer disposed near the liquid level of the cleaning liquid in the tank and connected to a humidifier, an exhaust pipe for exhausting air in the cleaning draft, and a displacement control means provided on the exhaust pipe. The measured humidity value is fed back to the humidifier to control the supply amount of water vapor or water droplets from the humidifier within a predetermined range. Wet cleaning device for the substrate, characterized in that so as to exhaust the air in the exhaust amount in the predetermined range. 5. The clean air supply means comprises a blower and a dust filter connected to the air discharge side of the blower, and the humidifier directs water vapor or atomized water droplets toward the cleaning liquid level of the cleaning tank in a vertical direction. The displacement control means includes a damper that can automatically adjust the opening,
It consists of an air flow meter or a barometer provided on the exhaust pipe, and these instruments are connected to a damper, and the measured values by the instrument are fed back to the damper,
The wet cleaning apparatus for a substrate according to claim 5, wherein the opening degree is controlled. 6. A humidifier which supplies steam or mist-like water droplets whose temperature is controlled within a predetermined range, and controls the temperature of clean air supplied vertically downward toward the cleaning liquid level within a predetermined range. The wet cleaning apparatus for a substrate according to claim 5, wherein an air conditioner for controlling the inside is provided.