JP2003117508A - Cleaning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a compression and decompression load and to shorten cleaning time. SOLUTION: This cleaning device is provided with a cleaning tank 1 which cleans an article W to be cleaned housed in the tank by introducing a supercritical fluid (or subcritical fluid) and in or from which the article W can be taken in or out in the state where the environment in the tank is maintained almost uniformly, circulating channels L1 and L2 which introduce the supercritical fluid (or subcritical fluid) lead-out from this cleaning tank 1 to the cleaning tank 1 again, and a porous membrane-type separator which is interposed in the middle of the circulating channel and separates and removes a soluble pollutant in the supercritical fluid (or subcritical fluid) lead-out from the cleaning tank under the same pressure condition as the cleaning tank.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cleaning device for cleaning microfabricated parts such as semiconductor devices and liquid crystal displays using a supercritical fluid or a subcritical fluid.

[0002]

2. Description of the Related Art In recent years, a cleaning device using a supercritical fluid has been attracting attention as a device for cleaning microfabricated parts such as semiconductor elements and liquid crystal displays. What is a supercritical fluid?
It refers to a fluid in the region above the critical temperature and critical pressure peculiar to a substance. This supercritical fluid has a viscosity, a diffusion coefficient, a density, and a dissolving power intermediate between those of gas and liquid. Also, originally
Since the gas is used after being compressed, it behaves as a gas when the pressure is returned to the normal pressure.

Materials mainly used as a cleaning medium (cleaning fluid) for a supercritical fluid are carbon dioxide, sulfurous acid gas, nitrous oxide, ethane, propane, CFC gas and the like. For example, carbon dioxide often used becomes a supercritical fluid under the conditions of a temperature of 31.06 ° C. or higher and a pressure of 74.8 atm or higher.

An example of a cleaning device using this type of supercritical fluid is disclosed in JP-A-5-47732 and JP-A-7-2847.
39, Japanese Patent Laid-Open No. 8-206485, and the like.

Cleaning using a supercritical fluid means that a cleaning medium (eg CO ₂ ) is brought into a high pressure supercritical state and is introduced into a cleaning tank containing an object to be cleaned, and the supercritical fluid is removed from the cleaning tank. By contacting the object to be cleaned, the organic contaminants adhering to the object to be cleaned are dissolved and removed. In this case, in the conventional apparatus, cleaning is performed by batch processing, and one cleaning is generally performed in the following process order.

(1) Put an object to be cleaned in a cleaning tank and close the lid. (2) A supercritical fluid is generated and introduced into a cleaning tank to perform cleaning with the supercritical fluid. (3) The supercritical fluid is discharged from the cleaning tank. (4) Open the lid of the cleaning tank and take out the object to be cleaned.

Here, generally, Japanese Patent Laid-Open No. 7-28473
As in the apparatus described in Japanese Patent Publication No. 9, the supercritical fluid discharged from the cleaning tank is decompressed into a gas gas, whereby organic contaminants dissolved in the supercritical fluid are separated and regenerated cleaning. The medium is recycled by returning it to the line that supplies the supercritical fluid to the cleaning tank.

Further, as in the apparatus described in Japanese Patent Application Laid-Open No. 8-206485, during cleaning with a supercritical fluid, the supercritical fluid is circulated in a circulation path connected to the cleaning tank, so that it flows into the cleaning tank. It is known that the cleaning effect is enhanced by causing the above phenomenon, and at that time, a filter is interposed in the course of the continuous circulation path to filter the contaminants.

[0009]

By the way, all of the conventional cleaning devices of this type perform cleaning in a batch process, and it is necessary to increase or decrease the pressure of the cleaning medium for each cleaning. . Therefore, when a large number of treatments are performed, it is necessary to frequently repeat the pressurization and depressurization, which results in a heavy burden of pressurization and depressurization. As a result, there is a problem that the operation cost is high, the cleaning efficiency is low, and the pressure fluctuation due to the pressurization and depressurization is large, so that the device life is shortened. Further, there is also a problem that cleaning time becomes long because it takes time to pressurize and depressurize.

In view of the above circumstances, it is an object of the present invention to provide a cleaning device using a supercritical fluid or a subcritical fluid, which can reduce the load of pressurization and decompression and can shorten the cleaning time.

[0011]

According to a first aspect of the present invention, in a device for cleaning an object to be cleaned with a supercritical fluid or a subcritical fluid, the inside of the tank is introduced by introducing the supercritical fluid or the subcritical fluid. A cleaning tank in which the object to be cleaned contained in the container can be washed and the object to be cleaned can be taken in and out while the environment inside the tank is kept substantially constant, and the supercritical fluid or subcritical fluid derived from the cleaning tank is washed again. And a separation means for separating and removing soluble contaminants in the supercritical fluid or the subcritical fluid that has been introduced from the cleaning tank under the same pressure condition as the cleaning tank and that is interposed in the circulation path. It is characterized by having.

In the cleaning apparatus of the present invention, first, as the cleaning tank, a cleaning tank is used in which the object to be cleaned can be put in and taken out while the environment inside the tank is kept substantially constant. As a specific example, a load lock type chamber is provided at the inlet and the outlet of the cleaning tank so that an object to be cleaned can be taken in and out without opening the inside of the cleaning tank to the atmosphere. By doing so, it is possible to reduce at least the burden of increasing and decreasing the pressure of the cleaning medium introduced into the cleaning tank. But,
Without pressurization / depressurization, it becomes impossible to separate soluble pollutants by vacuum evaporation.

Therefore, in the present invention, the supercritical fluid or the subcritical fluid led out from the cleaning tank is circulated using the circulation path, and the soluble pollutant is separated and removed by the separating means in the middle thereof. By separating and removing soluble pollutants while circulating the supercritical fluid or subcritical fluid in this way, the contaminants can be extracted and the cleaning power of the supercritical fluid or subcritical fluid can be always maintained. . Here, the circulation of the supercritical fluid or the subcritical fluid may be performed after cleaning the object to be cleaned or during the cleaning. When the supercritical fluid or the subcritical fluid is circulated during the cleaning, a flow can be generated in the cleaning tank, so that the cleaning effect is enhanced.

When the cleaning tank is provided with an inlet and an outlet separately and the inlet and the outlet are provided with chambers, respectively, the object to be cleaned can be continuously taken in and out of the cleaning tank. Processing becomes possible. Therefore,
The merit of circulating the supercritical fluid or subcritical fluid without depressurizing can be fully utilized.

According to a second aspect of the present invention, in the first aspect, as the separating means, a porous membrane type that permeates a supercritical fluid or a subcritical fluid and traps contaminants dissolved in the supercritical fluid is used. It is characterized by using the separator of.

In the present invention, since the porous membrane type separator is used as the separation means, the contaminants are separated and removed even when the concentration of the contaminants dissolved in the supercritical fluid or the subcritical fluid is low. be able to. Further, since the contaminants can be separated and removed under the same temperature condition as that of the cleaning tank, heat exchange is not required, and energy can be saved accordingly.

According to a third aspect of the present invention, in the second aspect, a plurality of separation paths including the separator are installed in parallel in the circulation path, and any separation path can be selectively used by operating a valve. Further, it is characterized in that a means for backwashing the porous membrane is provided by causing a washing fluid to flow to an unused separation path, which is the reverse of that in normal use.

When a pollutant dissolved in a supercritical fluid or a subcritical fluid is separated by using a porous membrane type separator, there is a possibility that the separation ability will decrease with the passage of time of use. However, in the present invention, a plurality of separation paths are provided in parallel, and the paths are appropriately switched so that the separator can be selectively used. Moreover, the porous membrane of the separator in the unused route can be backwashed. Therefore, the porous membrane can be constantly maintained at a constant performance, and the cleaning ability of the supercritical fluid or the subcritical fluid can be always recovered.

According to a fourth aspect of the present invention, in the first aspect, a rectification column for separating and removing soluble pollutants in the supercritical fluid or the subcritical fluid by distillation by heating is used as the separating means. It has a feature.

In the present invention, since the rectification column is used as the separating means, the contaminants can be efficiently separated and removed even when the concentration of the contaminants dissolved in the supercritical fluid or the subcritical fluid is high. You can

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a system diagram showing a main configuration of the cleaning apparatus according to the first embodiment. In the figure, 1 is a supercritical fluid (supercritical C
This is a cleaning tank for cleaning the object W to be cleaned contained in the tank by introducing O ₂ ). The cleaning tank 1 is capable of loading and unloading the object to be cleaned W while keeping the environment inside the tank substantially constant. Specifically, load-lock chambers (not shown) are provided at the inlet and outlet (not shown) of the cleaning tank 1, and the object W to be cleaned can be taken in and out without opening the inside of the cleaning tank 1 to the atmosphere. It has become.

FIG. 4 shows an example thereof. In this cleaning tank 1, an inlet 101 and an outlet 102 for the object W to be cleaned are separately provided on one side and the other side of the peripheral wall. And the entrance 101
A chamber 103 dedicated to the inlet is provided outside the chamber 102, a chamber 104 dedicated to the outlet is provided outside the outlet 102, and the chambers 103, 1 having a smaller volume than the cleaning tank 1 are provided.
Gate valves 105, 106, 107, and 1 are provided at both the communication port with the cleaning tank 1 of 04 and the communication port with the outside, respectively.
08 is provided. In addition, each chamber 103, 10
A supercritical fluid supply / discharge line 110 is connected to each of the parts 4. Then, by controlling the opening / closing of the supply / discharge line 110 and each of the gate valves 105, 106, 107, 108, the environment inside the cleaning tank 1 is kept substantially constant, and the cleaning device for the cleaning device is cleaned via the chambers 103, 104. Items W can be put in and taken out.

By using such a cleaning tank 1,
At least the burden of pressurization / depressurization of the cleaning medium introduced into the cleaning tank 1 can be reduced. However, if you do not reduce the pressure,
It becomes impossible to separate soluble pollutants by decompression as in the conventional case.

Therefore, in this cleaning apparatus, the supercritical fluid derived from the outlet 3 of the cleaning tank 1 is circulated to the inlet 2 of the cleaning tank 1 by using the circulation paths L1 and L2 equipped with the air supply fan 12, and in the middle thereof. Thus, the separation unit 10 separates and removes soluble contaminants. Further, as a central means of the separating part 10, a porous membrane type separator (separating means) 11 capable of permeating the supercritical fluid and capturing contaminants dissolved in the supercritical fluid is provided and separated. The pollutant is accumulated in the storage tank 15 through the valve 14 and, if necessary, the valve 16
By opening the box, it can be discharged to the outside through the discharge line L3.

The separator 11 in this case includes a circulation path L1,
Cleaning tank 1 is inserted in the middle of L2 under the same pressure condition as cleaning tank 1.
It is capable of separating and removing soluble contaminants in the supercritical fluid derived from
It uses a porous membrane of 0 to 100Å. As an example of the porous film, a glass film, a ceramics film, a metal film, a carbon film, a polymer film, a zeolite film, or the like having excellent heat resistance, pressure resistance, oil resistance, and particularly supercritical CO2 resistance is adopted. can do.

Next, the cleaning operation will be described. When starting the cleaning process, first, in a state where the object W to be cleaned is contained in the cleaning tank 1 in advance, the supercritical C in the cleaning tank 1 is stored.
Introduce O ₂ . The introduction of CO ₂ into the cleaning tank 1 is performed by using a separately provided supply line (not shown). The supply line, the CO ₂ that is supplied from the CO ₂ tank is raised to a predetermined high pressure by the compressor, the boosted CO ₂ is heated in the heat exchanger to a supercritical state is introduced from the inlet 2 to the cleaning vessel 1 .

Then, the supercritical fluid is brought into contact with the object W to be cleaned in the cleaning tank 1 to extract and remove the contaminants adhering to the object W to be cleaned. When the first cleaning is completed, the cleaned object W that has been cleaned is moved to the outlet chamber 104, and the next object W to be cleaned previously stored in the inlet chamber 103 is moved to the cleaning tank 1 (FIG. 4). reference). When moving, the gate valves 106 to 108 and the supply / discharge line 1
By controlling 10, the object W to be cleaned can be taken in and out while maintaining the environment in the cleaning tank 1 in a substantially constant state. After that, by repeating this operation,
The object to be cleaned W can be continuously and successively cleaned.

As described above, by loading and unloading the object W to be cleaned into and out of the cleaning tank 1 through the chambers 103 and 104, the cleaning tank 1 does not need to be opened to the atmosphere, so that the cleaning tank 1 having a large capacity can be used. It is not necessary to supply or discharge the supercritical fluid, and therefore, it is possible to reduce the load of the fluid required for cleaning and the load of pressurization and depressurization.

Further, the supercritical fluid used for the cleaning is circulated after the cleaning once or continuously during the cleaning.
Circulate through L2. By doing so, the contaminants dissolved in the supercritical fluid are not decompressed and the separator 1
It can be separated and removed by 1, and a constant detergency can be always maintained. In addition, when the supercritical fluid is circulated during the cleaning, a flow can be generated in the cleaning tank 1, so that the cleaning effect can be enhanced.

As described above, since the contaminants can be removed by the separator 11 under the same pressure as that of the cleaning tank 1 during the circulation of the supercritical fluid, a large number of objects to be cleaned can be cleaned. However, it eliminates the need for repeated frequent boosting and depressurizing. Therefore, the boosting energy can be saved, the life of the high-voltage device can be extended, and the operating cost and equipment cost can be reduced. Moreover, since the time required for pressurization and depressurization can be omitted, the total cleaning time can be shortened. Also,
Since this cleaning apparatus uses the porous membrane type separator 11, the contaminants can be separated and removed even when the concentration of the contaminants dissolved in the supercritical fluid is low. The contaminants can be separated and removed under the same temperature conditions as the cleaning tank 1. Therefore, there is no need for heat exchange, energy can be saved correspondingly, and the apparatus can be simplified.

The separating section 11 may be constituted by a plurality of routes, as shown in FIG.

That is, in the cleaning apparatus according to the second embodiment of the present invention, the main part of which is shown in FIG. 2, the separation paths L11 and L12 equipped with a porous membrane type separator are arranged in parallel in the middle of the circulation paths L1 and L2. 2 systems are incorporated into. First and second separation path L1
1, L12, inlet valves V11 and V21, separators M1 and M2 having a porous membrane 20, and outlet three-way valve V1.
3, V23 are provided. Also, each separator M1, M
The pollutant discharge port 2 has a discharge line L3 with discharge three-way valves V12 and V22 connected to the pollutant storage tank 22.
1, L32 are connected.

Further, the outlet three-way valves V13, V23
A backwash line L34 for connecting the washing liquid from the washing liquid storage tank 24 to the separators M1 and M2 by the pump 25 in the opposite direction to the normal use is connected to the three-way valve V12 for discharging.
The post-washing liquid discharge line L33 for introducing the post-washing post-washing liquid that has passed through the separators M1 and M2 in the reverse direction from the normal use to the post-washing liquid storage tank 23 is connected to V22.

In the apparatus constructed as described above, the inlet valves V11, V21, the outlet three-way valves V13, V23, and the discharge three-way valves V12, V22 are operated.
Either the first separation path L11 or the second separation path L12 can be selected (both can be selected in some cases), and the supercritical fluid derived from the cleaning tank 1 can be circulated. For example, when the supercritical fluid derived from the cleaning tank 1 is caused to flow through the separation path L1 or L2 by the suction force of the air supply fan (see FIG. 1), the separation membrane 2 of the separators M1 and M2 is separated.
0 separates the supercritical fluid and the organic pollutants dissolved in it from each other. That is, C having a small molecular weight and high condensability
O ₂ has a high permeability to the porous membrane 20 and thus selectively permeates, and is sent to the cleaning tank 1 via the outlet three-way valves V13 and V23 to be recycled. On the other hand, other organic contaminants cannot pass through the porous membrane 20 and are collected in the contaminant storage tank 22 via the three-way valves V12 and V22 for discharge.

Here, when the contaminants dissolved in the supercritical fluid are separated by using the porous membrane type separators M1 and M2, the separation ability may decrease as the use time elapses. However, in this apparatus, two systems of separation paths L1 and L2 are provided, and the paths are appropriately switched to separate the separators M1 and M2.
By selectively using, the separation ability can be maintained. Moreover, the backwash can be applied to the porous membranes 20 of the separators M1 and M2 which are not used.

This will be described. For example, after operating for a long time using the first separation path L11, the separation efficiency of the porous membrane 20 of the first separator M1 becomes poor, or the pressure difference before and after the porous membrane 20 becomes large. If the first separator M1 is closed, the inlet valve V11 of the first separation path L11 is closed and the second inlet valve 21 is opened.
Instead of the second separator M2 is used.

At this time, the porous membrane 20 of the unused first separator M1 is backwashed. As the procedure, the directions of the outlet three-way valve V13 and the discharge three-way valve V12 are changed, and the cleaning liquid in the tank 24 is pumped by the pump 25 to the three-way valve V13.
Backflow into separator M1 via V12. Then, the cleaning liquid sent out from the backwash line L34 is passed through the porous membrane 20 of the separator M1 in reverse, and the liquid after cleaning is collected in the storage tank 23 via the after-cleaning liquid discharge line L33.

After backwashing, the direction of the outlet three-way valve V13 is changed so that CO ₂ emitted from the outlet three-way valve V23 on the second separation path L12 side is removed from the three-way valve V13 and the separator M1. Flow through the three-way valve V12. As a result, the three-way valve V13, the separator M1, the three-way valve V1
The residual cleaning liquid of No. 2 is collected in the liquid storage tank 23 after cleaning. In this way, by performing backwashing, the separation performance of the porous membrane 20 of the separators M1 and M2 is restored. Therefore, a high separation capacity can be maintained at all times, and the supercritical fluid cleaning capacity can always be enhanced.

The temperature and pressure conditions for washing with a supercritical fluid and separation of contaminants are as follows: temperature 30 to 200 ° C., pressure 7 to 20 MPa, preferably temperature 30 to 100 ° C., pressure 7 to 10 MPa. Set. Further, as a cleaning liquid for backwashing the separation membrane, a detergent such as alcohol, benzene, toluene, acetone or THF can be used.

Next, a cleaning apparatus according to the third embodiment of the present invention will be described. FIG. 3 is an overall configuration diagram of the cleaning device. In the figure, 1 is a cleaning tank, 2 is a cleaning fluid inlet of the cleaning tank, and 3 is an outlet. The structure of the cleaning tank 1 is the same as that of the first embodiment. Circulation paths L41, L42 with a rectification tower 50 as a soluble contaminant separating means interposed therebetween are connected to the inlet 2 and the outlet 3 of the cleaning tank 1, and via the rectification tower 50,
The cleaning fluid derived from the outlet 3 of the cleaning tank 1 is returned to the inlet 2 of the cleaning tank 1 and circulated.

On the circulation path L41 between the rectification tower 50 and the washing tank 1, a cooler 41 and a gas-liquid separator 4 are arranged in this order from the rectification tower 50 side.
2. A heater 43 is provided. The gas-liquid separator 42 is
It plays the role of separating the non-condensed gas out of the system out of the fluid that has come out of the rectification column 50 and cooled by the cooler 41. The outlet 52 of the rectification tower 50 is at the top, and the circulation path L41 on the secondary side is connected thereto. Also, the rectification tower 50
The inlet 53 is located at the bottom, where the primary circulation path L4
2 is connected.

The heat exchanger 51 for heating is located in the lower part of the rectification column 50. By heating and distilling the supercritical fluid here, CO ₂ rises in the rectification column 50 and is dissolved on the way. Any pollutants that have separated are dropped down. At the lower end of the rectification column 50, an outlet 54 for a fluid containing a high concentration of pollutants is provided, and the fluid taken out from this is the filter 5
Enter the oil separator 59 via 8. And filter 5
8 and the CO ₂ regenerated by the oil separator 59 are cooled by the cooler 5
After being cooled in 7, the pressure is increased by the high-pressure pump 56 and is again introduced into the lower part of the rectification column 50. Note that the filter 58
The pollutants captured by the oil separator 59 and the oil separator 59 are collected by the valve 6
It is taken out of the system by opening 1, 63. Further, a CO ₂ introduction line L40 for introducing fresh CO ₂ fed from a tank (not shown) into the rectification column 50 while being pressurized by the high-pressure pump 40 is connected to the lower part of the rectification column 50. ing.

In this cleaning device, the supercritical fluid introduced into the cleaning tank 1 can be circulated by passing through the circulation paths L41 and L42 equipped with the rectification column 50.
Then, by the action of the rectification column 50 during circulation, the contaminants dissolved in the supercritical fluid can be separated and removed, and a constant detergency can always be maintained. When the supercritical fluid is circulated during the cleaning, a flow can be generated in the cleaning tank 1, so that the cleaning effect can be enhanced.

The removal of soluble pollutants by the rectification column 50 is continuously performed under the same pressure as that of the washing tank 1.
Therefore, even when cleaning a large number of objects to be cleaned, it is possible to eliminate the need for repeated frequent pressurization and depressurization, save pressurizing energy, and extend the life of the high-voltage device. The cost and equipment cost can be reduced. Moreover, since the time required for pressurization and depressurization can be saved, there is an advantage that the total cleaning time can be shortened.

Here, for example, the conditions of the cleaning tank 1 are set to a temperature> 30 ° C. and a pressure> 7 MPa (supercritical state).
The conditions of the gas-liquid separator 42 are temperature <30 ° C. and pressure 7
The condition of the heater 43 is set to MPa (liquid state) according to the linear temperature and pressure of the cleaning tank 1.

Although a supercritical fluid is used as the cleaning fluid in the above embodiment, a subcritical fluid may be used instead of the supercritical fluid.

[0047]

As described above, according to the inventions of claims 1 to 4, while the supercritical fluid (or subcritical fluid) in the cleaning tank is externally circulated, it is supercritical under the same pressure condition as the cleaning tank. Since contaminants are separated from the fluid (or subcritical fluid), it is possible to eliminate the need for repeated frequent pressurization / depressurization even when a large number of objects to be cleaned are continuously cleaned.
Therefore, the boosting energy can be saved, the life of the high-voltage device can be extended, and the operating cost and equipment cost can be reduced. Moreover, since the time required for pressurization and depressurization can be omitted, the total cleaning time can be shortened.

In particular, according to the invention of claim 2, since a porous membrane type separator is used as the separating means, when the concentration of contaminants dissolved in the supercritical fluid (or subcritical fluid) is low. Even in this case, the contaminants can be efficiently separated and removed. In addition, since contaminants can be separated and removed under the same pressure and temperature conditions as the cleaning tank, there is no need for extra heat exchange, and energy can be saved. Further, according to the invention of claim 3, since the porous membrane can be backwashed, the performance of the separator can be always maintained in a constant state.

Further, according to the invention of claim 4, since the rectification column is used, even when the concentration of the contaminant dissolved in the supercritical fluid (or subcritical fluid) is high, the contaminant is efficiently polluted. The substance can be separated and removed.

[Brief description of drawings]

FIG. 1 is a main part configuration diagram of a first embodiment of the present invention.

FIG. 2 is a configuration diagram of main parts of a second embodiment of the present invention.

FIG. 3 is a configuration diagram of a cleaning device according to a third embodiment of the present invention.

FIG. 4 is a configuration diagram of a cleaning tank used in each embodiment.

[Explanation of symbols]

1 cleaning tank 2 entrance 3 exit 11 Separator (separation means) 20 Porous membrane 50 rectification tower W to be cleaned L1, L2, L41, L42 Circulation path L11, L12 separation path L34 backwash line M1, M2 separator V11, V21 inlet valve (selection means) V12, V22 exhaust three-way valve V13, V23 outlet three-way valve

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Deng Jian             1002-14 Mukoyama, Naka-machi, Naka-gun, Ibaraki Prefecture             Terari Co., Ltd.             Inside (72) Inventor Kenji Nishimura             1002-14 Mukoyama, Naka-machi, Naka-gun, Ibaraki Prefecture             Terari Co., Ltd.             Inside F-term (reference) 2H088 FA21 FA30 MA20                 3B116 AA48 AB01 BB02 BB21 BB82                       BB90 CD22 CD31

Claims (4)

[Claims] 1. An apparatus for cleaning an object to be cleaned using a supercritical fluid or a subcritical fluid, wherein the object to be cleaned contained in the tank is cleaned by introducing the supercritical fluid or the subcritical fluid, and the tank is also cleaned. A cleaning tank in which the object to be cleaned can be taken in and out with the internal environment kept substantially constant, a circulation path for introducing the supercritical fluid or subcritical fluid derived from the cleaning tank into the cleaning tank again, and a circulation path for the circulation path. A cleaning device comprising: a separation means interposed in the middle of the cleaning tank and separating and removing soluble contaminants contained in the supercritical fluid or the subcritical fluid derived from the cleaning tank under the same pressure condition as the cleaning tank. 2. A porous membrane-type separator that permeates a supercritical fluid or a subcritical fluid and captures contaminants dissolved in the supercritical fluid or the subcritical fluid is used as the separating means. The cleaning device according to claim 1, wherein: 3. A plurality of separation paths provided with the separator are installed in parallel in the circulation path, and any separation path can be selectively used by operating a valve. 3. The cleaning apparatus according to claim 2, further comprising means for backwashing the porous membrane by flowing a washing fluid to the separation path, which is the reverse of that in normal use. 4. A rectification column for separating and removing soluble pollutants in a supercritical fluid or a subcritical fluid by distillation by heating is used as the separating means.
The cleaning device described.