JP3932334B1 - How to operate the clean unit - Google Patents

Abstract

Provided is a clean unit capable of easily obtaining a clean environment having an extremely high cleanliness of class 1 or higher with an extremely simple configuration without using a huge clean room.
In a clean unit having a circulation type filter that is maintained in a clean environment and capable of being maintained in a clean environment, the circulation type filter has a plurality of filter media different from each other or a plurality of pore sizes of the filter media different from each other. An active dust filter provided in series and / or in parallel is included at least in part.
[Selection] Figure 1

Description

  The present invention relates to a clean unit, a connected clean unit, a method for operating a clean unit, and a clean work room, and is particularly suitable for application to the realization of a clean air (air) environment free from dust particles such as dust and bacteria. It is.

  In order to improve the quality and improve the yield of precision products for applications such as the electronics industry, precision machine industry, and precision printing, a clean room for removing dust is required. According to the International Technology Roadmap for Semiconductor (ITRS), the required cleanliness of clean rooms will be relaxed to the normal atmospheric level in 2018 due to the progress of local cleanliness. Still far from that.

  A technique for providing a clean work space without using a clean room has been proposed. For example, as a workbench that enables work in a clean environment, it is a workbench that takes outside air from the opening of the work space, filters this air through a filter, and blows it out from the top of the work space into the work space, A communication path that connects the work space and the outside is provided on the side or back of the work space, an object storage space is formed in the communication path, and opening / closing means for partitioning the outside and the work space are provided on both sides of the object space. It has been proposed (see Patent Document 1).

  In addition, a clean bench that works in a dust-free state has been proposed in which an opening having a chucking mechanism is provided on the side surface to enable connection of a plurality of clean benches (see Patent Document 2). In addition, the box can be moved in a clean environment, and the box includes a plurality of filters and a blower. The upper part is provided with a coarse filter and a high collection filter, and the lower part is a saw board. And a lower filter, an open / close lid for taking in and out the workpiece on one side, a glove on the other side, and a blower between the coarse filter and the high collection filter A box has been proposed (see Patent Document 3).

Also, in a clean box for treating and handling infectious pathogens, a clean box with a heat sterilizer having a plurality of sterilization heating tubes and means for forcibly sending air in the work box into the heating tubes has been proposed. (See Patent Document 4)
Further, a blower outlet is formed on one surface of the box-shaped casing, and a special suction port is formed on at least two of the other surfaces, and the gas taken from the suction port is discharged from the blower port, and the blower port. A gas purification unit has been proposed in which a filter for purifying gas to be discharged from the casing is provided in the casing, and a fixture for a lid for selectively closing each of the suction ports is provided (see Patent Document 5).

Also, a manufacturing apparatus for a clean space technology manufacturing line in which a plurality of compartments are connected has been proposed (see Patent Document 6).
In addition, a clean tunnel has been proposed in which a large number of clean modules are connected to form a clean space (see Patent Document 7). This is a contrivance to minimize the destruction of the clean environment by inserting a dividing plate between the clean modules to minimize the external opening.
In addition, a clean bench module system in which a plurality of clean bench units are connected in an airtight manner by connecting means, and the work spaces in each clean bench unit are connected so that an airtight passage having a clean room environment can be adjusted in the length direction. Has been proposed (see Patent Document 8).
Moreover, the multi-chamber apparatus comprised by a module is proposed (refer patent document 9).

Some clean units such as work benches, clean benches, clean boxes, glove boxes and the like proposed in Patent Documents 1 to 8 above can obtain a class 10 clean environment. However, it was necessary to be placed in a clean environment of a certain degree (about 1000), and these single clean units could only be completed and closed inside.
Further, in the above Patent Documents 1, 2, 6, 7, and 8, it is proposed to connect a plurality of clean units in order to perform a plurality of processes while maintaining a clean environment. Only a single linear arrangement connecting the clean units in the left-right direction could be taken. For this reason, when trying to connect as many clean units as necessary for the total series of processes, a long installation space is required in that direction, and the length of the building that houses this clean unit system must be increased accordingly. I didn't get it.

In addition, the multi-chamber apparatus described in the above-mentioned Patent Document 9 can only connect in one direction for each module, and has poor expandability and flexibility of inter-module connection.
In addition, during the total series of processes from the most upstream process to the most downstream process, for example, processes such as resist coating, mask alignment, exposure, development, and etching are repeated with other processes in between. Often appears. In such a case, connecting a number of clean units that perform these processes in the above-mentioned single linear arrangement results in an enormous number of clean units that make up the clean unit system. However, it is advantageous because the same manufacturing equipment can be reused, and it cannot escape from the spell of enormous capital investment.

  Furthermore, if the same clean unit is used repeatedly for the same type of process while maintaining the single linear clean unit arrangement, the above-mentioned single linear clean unit arrangement It is necessary to move back and forth between the upstream clean unit and the downstream clean unit many times. In addition, an unexpected accident such as dropping may occur when a workpiece such as a substrate is transported through the connecting portion between the clean units, which may reduce the yield.

  Recently, a clean unit that can solve the problems of Patent Documents 1 to 9 has been proposed (see Patent Document 10). According to this, at least one of the rear part, the upper part and the lower part of the work room that can be maintained in a clean environment, and the upper part of the work room of the clean unit provided with the connecting part on at least one side part is active. A single dustproof filter (HEPA (high efficiency particulate air) filter) is provided, and an airtight tube is directly connected to the side of the working room and connected to the entrance of the dustproof filter so that the gas circulates. Configure. The average value and the maximum value of the cleanliness of this clean unit are equivalent to class 10. In addition, this clean unit can easily configure a desired clean unit system by connecting a plurality of units in a polygonal line arrangement, a loop arrangement, etc., according to the process to be executed by using the connecting portion. it can. As described above, a mechanism for achieving high cleanliness by configuring the clean unit in a circulation type has been reported (see Non-Patent Documents 1 and 2).

Japanese Patent Laid-Open No. 2-15984 JP-A-1-171646 Japanese Patent Laid-Open No. 2-107348 Japanese Utility Model Publication No. 51-156692 Japanese Utility Model Publication No. 61-145240 Japanese Patent Laid-Open No. 3-7838 Japanese Patent No. 2517112 JP-A-5-157302 JP-A-6-267806 International Publication No. 04/114378 Pamphlet A. Ishibashi, H. Kaiju, Y. Yamagata and N. Kawaguchi: Electron. Lett. 41, 735 (2005) H. Kaiju, N. Kawaguchi and A. Ishibashi: Rev. Sci. Instrum. 76, 085111 (2005)

However, the clean unit proposed in the above-mentioned Patent Document 10 is not necessarily sufficient in reachable cleanliness, and further improvement in cleanliness has been demanded.
In addition, HEPA filters and ULPA (ultra low penetration air) filters used as dustproof filters existed only in the type in which the filter part directly contacts the outside air, but were obtained by experiments conducted independently by the present inventors. According to the knowledge, it has been found that the direct contact of the filter part with the outside air is one of the factors that hinder further improvement in cleanliness.
Therefore, in view of the situation as described above, the problem to be solved by the present invention is that a large-scale and small turn does not work as before, without using a huge clean room that requires huge capital investment and fixed asset burden, With a very simple configuration, it is possible to easily obtain a clean environment with an extremely high cleanliness of Class 1 or higher, and solve the poor space utilization efficiency of conventional clean units that can only be connected in a straight line. The total performance can be maximized in terms of investment, work efficiency, and effective use of the room area, and the process is highly flexible in response to a total series of process flows according to the purpose. It is to provide a connected clean unit that can be easily executed at low cost and a clean unit suitable for use in this unit. .

Another problem to be solved by the present invention is that dust particles such as dust and bacteria in the work space can be suppressed to 1 or less, or 0.1 or less over any size, that is, to any size. It is to provide a dust-free and sterile environment.
The final problem to be solved by the present invention is that the technologies in various fields such as nanotechnology, biotechnology, and plant factory, which have been conventionally performed in completely different buildings and rooms, are integrated and integrated on one integrated platform. It is to provide an environment that can be processed.
The above and other problems will become apparent from the following description of the present specification with reference to the accompanying drawings.

In order to solve the above problem, the first invention is:
A clean unit that has a circulating filter and can be maintained in a clean environment.
The circulation type filter includes at least a part of a plurality of active dust filters having different filter media or different pore diameters of the filter media provided in series and / or in parallel.
Thus, as far as the present inventors know, no proposal has been made so far to provide a plurality of active dust filters having different filter media or different pore sizes of the filter media in series and / or in parallel.

The second invention is
In a connected clean unit in which multiple clean units that can be maintained in a clean environment are connected,
At least one clean unit
A clean unit having a circulation filter and capable of maintaining a clean environment, wherein the circulation filter includes a plurality of active dust filters having different filter media or different filter media pore diameters in series and / or Or what is provided in parallel is included in at least one part.

  In the first and second inventions, for example, glass fiber or polytetrafluoroethylene (PTFE) can be used as the filter medium. In this case, these active dust filters preferably have a smaller minimum diameter of dust particles that can be removed as the downstream active dust filter. Preferably, at least one of the plurality of active dust filters uses a self-generated dust filter (for example, a ULPA filter using polytetrafluoroethylene as a filter medium). In one suitable example, an active dust filter (HEPA filter) using glass fiber as a filter medium and an active dust filter (ULPA filter) using polytetrafluoroethylene as a filter medium are provided in series, with the former on the upstream side, Install the clean unit so that the latter is on the downstream side.

The third invention is
A clean unit that has a circulating filter and can be maintained in a clean environment.
At least part of the circulating filter is a first active dust filter in which the minimum diameter of the removable dust particles is the first particle size and the minimum diameter of the removable dust particles is the first particle size. A second active dust filter having a smaller second particle size,
The first active dust filter and the second active dust filter are provided in parallel to the clean unit;
The first active dust filter and the second active dust filter are configured to be switchable.
Here, the first active dust filter is, for example, a HEPA filter using glass fiber as a filter medium, and the second active dust filter is, for example, a ULPA filter using polytetrafluoroethylene as a filter medium. It is not limited to these. For example, the same filter medium is used for the first active dust filter and the second active dust filter, and the hole diameter (mesh hole diameter) of the filter medium of the second active dust filter is set to the hole diameter of the filter medium of the second active dust filter. It may be smaller.

The fourth invention is:
A method for operating a clean unit having a circulation type filter and capable of maintaining a clean environment,
At least part of the circulating filter is a first active dust filter in which the minimum diameter of the removable dust particles is the first particle size and the minimum diameter of the removable dust particles is the first particle size. A second active dust filter having a smaller second particle size,
The first active dust filter and the second active dust filter are provided in parallel to the clean unit;
The first active dust filter and the second active dust filter are configured to be switchable,
After dust fine particles having the first particle diameter or larger are removed by the first active dust filter, the first active dust filter is switched to the second active dust filter and dust having the second particle diameter or larger is switched. It is characterized by removing fine particles.
Preferably, dust particles are removed by the first active dust filter and the second active dust filter, and then an inert gas such as a rare gas or nitrogen gas is introduced into the working chamber to replace the air. By doing so, the environment in the working chamber can be made into a non-oxygen atmosphere with high cleanliness.

The fifth invention is:
In a connected clean unit in which multiple clean units that can be maintained in a clean environment are connected,
At least one clean unit
A clean unit having a circulation type filter and capable of being maintained in a clean environment, wherein the circulation type filter has at least a part thereof, and the minimum diameter of dust particles that can be removed is the first particle diameter. A first active dust filter and a second active dust filter in which a minimum diameter of removable dust particles is a second particle size smaller than the first particle size;
The first active dust filter and the second active dust filter are provided in parallel to the clean unit;
The first active dust filter and the second active dust filter are configured to be switchable.

The sixth invention is:
A clean unit that has a circulating filter and can be maintained in a clean environment.
A gate valve is provided above and below the active dust filter of the circulation filter.

The seventh invention
A method for operating a clean unit having a circulation type filter and capable of maintaining a clean environment,
Gate valves are provided above and below the active dust filter of the circulation filter,
The dust valve is removed by the active dust filter, and then the gate valve is closed.
As far as the present inventors know, no proposal has been made so far to provide gate valves above and below the active dust filter (or at the inlet and outlet).
Preferably, dust particles are removed by an active dust filter, and then an inert gas is introduced into the working chamber to replace the air.

The eighth invention
In a connected clean unit in which multiple clean units that can be maintained in a clean environment are connected,
At least one clean unit
The clean unit has a circulation type filter and can be maintained in a clean environment, and is characterized in that gate valves are provided above and below the active dust filter of the circulation type filter.
In the sixth to eighth inventions, it is preferable that these gate valves are closed after dust fine particles are removed by the active dust filter. In this case, after removing dust particles with the active dustproof filter, an inert gas may be introduced into the working chamber to replace the air.

The ninth invention
A non-vacuum clean working chamber having an air circulation mechanism that can be maintained in a clean environment, wherein the total number of dust particles having a particle diameter of 0.01 μm or more is less than one. Is.
Preferably, the total number of dust particles having a particle diameter of 0.01 μm or more is less than 0.1.
Here, it has not been reported so far that the total number of dust fine particles having a particle diameter of 0.01 μm or more in the clean work chamber can be less than one, and the present inventors have achieved for the first time. .
In the first to ninth inventions, the circulation type filter or the air circulation mechanism is typically constituted by an active dustproof filter and a circulation duct.

で記述される。このとき、

および

と定義すると、ダスト微粒子密度は

となり、時間が十分たてば、第２項は急速にゼロに近づくため、第１項、すなわちα_n ／β_n ＝（Ｓσ／Ｖ₀ ）／（γＶ／Ｖ₀ ）＝Ｓσ／γＶのみが残る。この項は外気のダスト密度を含まないため、このクリーンユニットの設置環境によらず、究極の清浄度が得られることがわかる。ここで特徴的なことは、ターボシステムを用いないクリーンユニットでは、作業室の清浄度は１−γあるいはそのべき乗（１−γ）ⁿ で支配されるのに対し、ターボシステムを用いるクリーンユニットでは、作業室の清浄度は１／γで支配されることである。また、Ｓσ／γＶを最小化することが重要である。 Here, the cleaning process according to the first to ninth inventions will be described. Consider a case where an active dustproof filter and a circulation duct are provided in a clean unit work room or a clean work room (turbo system). At this time, the dust density n (t) in the working chamber is expressed as follows: the air volume of the dustproof filter is V, the volume of the working chamber is V ₀ , the inner area is S, the desorption rate of dust particles per unit area / unit time is σ The dust density of the installation environment is N ₀ and the dust collection rate of the dustproof filter is γ.

It is described by. At this time,

and

The dust particle density is defined as

When the time is sufficient, the second term rapidly approaches zero, so only the first term, that is, α _n / β _n = (Sσ / V ₀ ) / (γV / V ₀ ) = Sσ / γV Remain. Since this term does not include the dust density of the outside air, it can be seen that the ultimate cleanliness can be obtained regardless of the installation environment of the clean unit. What is characteristic here is that in a clean unit that does not use a turbo system, the cleanliness of the working room is governed by 1-γ or its power (1-γ) ⁿ , whereas in a clean unit that uses a turbo system, The cleanliness of the working room is governed by 1 / γ. It is also important to minimize Sσ / γV.

In the first to ninth inventions, the shape of the clean unit or the clean working chamber may be various shapes and is selected as necessary. Specific examples include a rectangular parallelepiped shape or a cubic shape, a rectangular solid shape or a cubic shape. The shape may be a deformed shape, spherical shape, hemispherical shape, ellipsoidal shape, cylindrical shape, or the like. The size of the inside of the work room is basically determined as appropriate according to the design according to the purpose of use. For example, the operator can use a glove or the like to perform various operations (processes) inside the work room. In order to be able to perform maintenance, such as cleaning, cleaning, etc.), it is desirable that the size of the work chamber reaches the entire work space from the outside, generally, Is selected within 1 m in width, height and depth, but is not limited thereto. On the other hand, if the size of the working chamber is too small, there is a possibility that the work may be hindered. Therefore, it is generally selected to be about 30 cm or more, but is not limited thereto. If you do not need to put your hands into the work chamber from the outside, for example when automating the work, or when carrying the clean unit with a sample etc., the size of the work chamber will be smaller. Is possible. This clean unit can be used for material processing, for example. This material treatment includes treatment of various materials such as inorganic materials, organic materials, and biomaterials. When multiple clean units are connected, for example, the same type of process that appears multiple times in a total series of process flows is provided in the multiple clean units with a portion where the clean units are connected in a loop arrangement. Thus, it can be executed in the same clean unit.
Since the clean unit or the clean working chamber may be non-vacuum, the clean unit or the clean working chamber may be composed of a plate-like hard member, or may be composed of a balloon or a balloon-like soft material.
In order to suppress dust generation from the inner wall of the clean unit or the clean working chamber, for example, all or a part of the inner wall may be coated with polytetrafluoroethylene.

When a plurality of clean units or clean work rooms are connected, the connected clean unit includes, for example, a nanotechnology process unit and / or a biotechnology process unit.
In the case of performing the connection, a connection part is provided on at least one of the rear part, the upper part and the lower part of the working chamber and at least one side part. Depending on how the clean unit is arranged two-dimensionally (planarly) or three-dimensionally (three-dimensionally), where the connecting part of the working room is provided in the rear, upper part, lower part and two sides It is decided appropriately. For example, when arranging the connected clean unit in a horizontal plane, in order to increase the degree of freedom of connection and increase the flexibility of the connected clean unit, preferably, the connected parts are provided at the rear and both sides of the working chamber. Each is provided. In this case, a total of three clean units can be connected to the rear and both sides of one clean unit. In addition, when the clean unit is arranged in a vertical plane, in order to increase the degree of freedom of connection and increase the flexibility of the connection clean unit, preferably, the connection part is provided at the upper or lower part of the working chamber and on both sides. Provided in each part. In this case, it is possible to connect a total of three clean units to the upper or lower part and both sides of one clean unit. The connecting portion includes, for example, an opening provided on the wall of the working chamber and a blocking plate provided so as to be able to open and close the opening. The blocking plate may be basically any one as long as it can be opened and closed, but is typically a sliding door or a door. The shut-off plate can be opened and closed manually, or a sensor such as an optical sensor is installed inside the work chamber, and an open-close mechanism for the shut-off plate is provided so that when the operator's hand or sample approaches the shut-off plate You may make it open and close. In addition, when a transport mechanism such as a belt conveyor is provided in the work chamber and a sample is transported between the entrance and the exit by this transport mechanism, when the sample is transported to the vicinity of the exit by the transport mechanism, this is detected by a sensor. The blocking plate may be opened and closed by an opening / closing mechanism upon detection. A sealing member such as packing may be provided on the barrier plate or the wall surface of the working chamber to improve the airtightness at the time of blocking.

A compact device can be accommodated in the clean unit (inside the work chamber) according to the purpose of use. Specifically, this apparatus includes, for example, various process apparatuses, wrapping apparatuses, analysis apparatuses (for example, scanning probe microscopes (SPM) such as an optical microscope, a scanning electron microscope (SEM), an atomic force microscope (AFM), etc.) Etc.), reaction equipment, micro chemical system, micro chemical reactor, exposure equipment, etching equipment, growth equipment, processing equipment, sterilization equipment, particle size filter, artificial light source, bio equipment, food processing equipment, inspection equipment, medical devices These include endoscope parts, contact lens manufacturing equipment, dialysis equipment, medical disposal manufacturing equipment, and pharmaceutical equipment. The artificial light source is used, for example, when performing cell line growth, plant growth, genetic experiments, and the like. In the case of growing a cell line or a plant body, as the artificial light source, a light-emitting diode or a semiconductor laser having a spectral half width of 30 nm or less, particularly a pulse-driven semiconductor laser is preferably used.
Moreover, the internal environment of the working room of the clean unit can be controlled in various ways. The internal environment control means includes, for example, a temperature control device, a humidity control device, a gas component control device, an adsorption device, an abatement device, a specific wavelength illuminator, a sealed / open environment selection mechanism, and the like. The internal environment can be controlled by a computer, for example.

  According to the above-mentioned connected clean unit, various material processing processes with high flexibility and low cost corresponding to a total series of process flow in fields such as nanotechnology, biotechnology, plant factory technology, etc. Material processing method that can be executed easily and with high flexibility for manufacturing various elements (LSI, light emitting diode, semiconductor laser, etc.) using inorganic materials or organic materials corresponding to the total series of process flow A device manufacturing method that can be easily executed at low cost with a tee, and can be easily executed at low cost with high flexibility in response to a total series of process flows. Realization of a plant growing method and the like becomes possible.

  According to the present invention, the circulation filter includes a plurality of active dust filters having different filter media or different filter media pore diameters, so that large dust particles can be first removed from the air in the clean unit. After cleaning with an active dust filter, cleaning with an active dust filter that can remove smaller dust particles makes the latter active dust filter extremely clean without imposing a burden on the latter An air environment can be obtained. In particular, it is possible to realize an extremely clean environment in which the total number of dust particles having a particle size of 0.01 μm or more in the clean unit or clean work chamber is less than 1 or less than 0.1.

And according to this invention, the various subject which was difficult to solve until now can be solved. In other words, conventional clean rooms for manufacturing electronic elements and electronic devices such as semiconductor LSIs and liquid crystal displays, clean rooms for bio and food, and plant factories using artificial light sources used large box-like spaces as a whole. There were problems such as high cost, expensive equipment required, small turning effect, plant growth was not optimized, etc. These problems were solved at once.
For example, in the manufacture of highly functional elements such as semiconductor elements typified by VLSI, starting from material input, film formation, lithography using UV (ultraviolet rays) or EUV (extreme ultraviolet rays), lithography such as electron beam lithography, etc. An integrated process that leads to product output through various processes such as etching and heat treatment is required. This manufacturing process has conventionally transferred a substrate between large, expensive and highly precise manufacturing apparatuses such as a film forming apparatus, a lithography apparatus, an etching apparatus, and a heat treatment apparatus which are arranged in a large and highly controlled clean room. Has been realized. Therefore, the manufacture of conventional high-performance elements is based not only on the construction of a huge building on a vast site, but also on the equipment industry that produces various kinds of manufacturing equipment. Similar problems also occur in bioclean reames and food processing clean rooms if the manufacturing apparatus is replaced with an apparatus related to biotechnology or food processing. For these reasons, in general, manufacturing ventures such as nanotech ventures and bio-ventures are subject to heavy capital investment, such as fixed assets, and the break-even point rises, and the probability of successful commercialization is not high. It was. This has generally been deeply concerned as the “death valley” that lies between basic research and industrialization. In other words, in the industry that manufactures conventional high-performance devices, the burden of capital investment and fixed asset maintenance is greater than that of the IT industry, especially the software industry, and it is difficult to start a manufacturing venture with nanotechnology as its main business. It can be said that there is. In order for nanotechnology to blossom its original potential, it is necessary to move away from the paradigm that, as represented by the Moore's Law of LSI, the advancement of device miniaturization requires huge precision infrastructure and equipment. It is necessary to plan.
The problem of such existing technology is to use a clean unit, a connected clean unit, or a clean work room according to the present invention to develop a hardware venture that has a low burden of maintaining fixed assets as well as a software venture. This can be solved by making it possible to easily construct a small-scale manufacturing apparatus or mini-fab system that does not require a clean room.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a front view of a clean unit according to the first embodiment of the present invention, and FIGS. 2A and 2B are a top view and a side view of the clean unit (illustration of active dustproof filters 45a and 45b is omitted).
As shown in FIGS. 1 and 2, this clean unit has a hexahedral box-shaped work chamber 41. Both side surfaces of the work chamber 41 are parallel to each other, the top surface and the bottom surface are also parallel to each other, the side surfaces and the top surface, the bottom surface, the front surface and the back surface are perpendicular to each other. Although it inclines by predetermined angle, for example, 70-80 degrees, in the direction which approaches, it is not limited to this. The front surface of the work chamber 41 is removable, and necessary devices such as a process device and an observation device can be put in the front surface with the front surface removed.

  Transfer boxes 42 and 43 that also serve as connectors and transport paths between the clean units are detachably provided on the left side and the back of the work chamber 41, respectively. Although not shown in FIGS. 1 and 2, an opening is provided in the wall of the work chamber 41 where the transfer boxes 42 and 43 are attached. Using these transfer boxes 42 and 43, it is possible to connect other clean units from the left side and the back side, and to carry samples and the like through these transfer boxes 42 and 43. Can be done. The transfer boxes 42 and 43 typically have an opening provided on the wall of the work chamber 41 and a blocking plate provided so that the opening can be opened and closed. The blocking plate may be basically any one as long as it can be opened and closed, but is typically a sliding door or a door. The shut-off plate may be opened and closed manually, or a sensor such as a light sensor is attached to the inside of the work chamber 41, and a shut-off plate opening / closing mechanism is provided so that the operator's hand or sample approaches the shut-off plate. You may make it open and close automatically. In addition, when a transport mechanism such as a belt conveyor is provided in the work chamber and a sample is transported between the entrance and the exit by this transport mechanism, when the sample is transported to the vicinity of the exit by the transport mechanism, this is detected by a sensor. The blocking plate may be opened and closed by an opening / closing mechanism upon detection. A sealing member such as packing may be provided on the barrier plate or the wall surface of the working chamber to improve the airtightness at the time of blocking. Although the dimension of the transfer boxes 42 and 43 is 15-20 cm, for example, it is not limited to this.

  In order to minimize the release of dust or dust from the inner wall of the work chamber 41, an adhesive sheet is preferably attached to at least a part of the inner wall of the work chamber 41, and is replaced after being used for a certain period of time, for example. When a multilayered adhesive sheet is used, a clean sheet surface can be obtained by peeling the adhesive sheets one by one. Further, by smoothing the inner wall surface of the working chamber 41 so that it does not have a Fourier component of surface irregularities in the same order as the diameter of the dust particles to be removed from the working chamber 41 at the spatial frequency, this particle size is reduced. Adsorption of the dust particles on the inner wall surface of the working chamber 41 can be minimized. In order to suppress the release of dust or dust from the inner wall of the work chamber 41, for example, all or a part of the inner wall surface may be coated with polytetrafluoroethylene.

Two circular openings are provided in the front wall of the work chamber 41, and a pair of manual gloves 44 are attached to these openings. An operator puts both hands into these manual work gloves 44 so that necessary work can be performed in the work chamber 41.
The size of the work chamber 41 is large enough to accommodate the necessary process equipment and the like, and the operator can put both hands into the manual work glove 44 and perform necessary work in the work chamber 41. Chosen by you. Specific examples of the dimensions of the working chamber 41 include depth a = 50 to 70 cm, width b = 70 to 90 cm, and height h = 50 to 100 cm, but are not limited thereto. Further, as a material constituting the work chamber 41, a transparent material such as an acrylic resin plate is preferably used so that the inside can be seen from the outside, but the material is not limited thereto. You may make it attach this acrylic resin board to a metal frame for mechanical reinforcement.

  Two active dustproof filters 45a and 45b having blowing power are connected in series to the upper surface of the working chamber 41, and a circulation duct 47 is attached to connect the upstream active dustproof filter 45a and the working chamber 41. Thus, the inside of the work chamber 41 can be maintained in a highly clean environment of class 0.00001 to class 0.1, for example. The active dustproof filters 45a and 45b have different minimum diameters of dust particles that can be removed, and the active dustproof filter 45b has a smaller minimum diameter of dust particles that can be removed than the active dustproof filter 45a. As the active dustproof filter 45a, for example, a HEPA filter using glass fiber as a filter medium is used, and as the active dustproof filter 45b, for example, a ULPA filter using polytetrafluoroethylene as a filter medium is used.

Next, an example of the operation method of this clean unit will be described. Here, first, it is assumed that the inside of the work chamber 41 has a low cleanliness like a normal indoor environment.
When both active dustproof filters 45a and 45b are operated, the air in the working chamber 41 passes through the circulation duct 47 and enters the active dustproof filter 45a, and dust particles having a large particle diameter are removed. Next, the air from which dust particles having a large particle diameter have been removed comes out of the active dust filter 45a and enters the active dust filter 45b, where the removal of dust particles having a smaller particle diameter is removed and cleaning is performed.

  As described above, according to the first embodiment, the active dust filter 45b that can remove dust particles having a larger particle diameter after removing dust particles having a larger particle diameter by the active dust filter 45a is used. Therefore, the active dustproof filter 45b is not clogged with the active dustproof filter 45b and the active dustproof filter 45b is not clogged as compared with the case where the active dustproof filter 45b is used for cleaning from the beginning. It can be cleaned to a cleanliness reachable by 45b. In addition, the life of the active dustproof filter 45b can be improved. Since this clean unit has a sealed structure, it does not depend on the installation environment, and it can maintain the internal high cleanliness environment even if it is installed in a normal office environment with low cleanliness. It is not necessary to install in a huge clean room, and the equipment cost can be greatly reduced.

FIG. 3 shows the dependence of the cleanliness of this clean unit on the particle size of dust particles. Inside the clean unit, the inner wall is treated as described above in order to suppress dust generation. In FIG. 3, Δ, □, and ○ are values when a HEPA filter is used, ◎ is a HEPA filter that uses glass fiber as a filter medium as an active dust filter 45a, and polytetrafluoroethylene is used as a filter medium as an active dust filter 45b. It is a value when a ULPA filter (self-dust-free filter) is used. The desorption rate σ (particle size: 0.1 μm) of the dust particles per unit area and unit time is 10.3 m ⁻² s ⁻¹ for the value Δ in FIG. 3 and 4.17 m ⁻² for the value □. The value of s ⁻¹ and ◯ is 0.83 m ⁻² s ⁻¹ . The volume of the work chamber 41 is 0.3 m ³ . As indicated by ◎ in FIG. 3, an extremely high cleanliness of class 0.0001 (ISO class-1) to class 0.00001 (ISO class-2) is obtained. The cleanliness of Class 0.0001 (ISO class-1) is the technology level of 2018 in the ITRS roadmap, and it is about 12 years ahead. As the dust counter, Lasair 110 of Tokyo Nuclear Service Co., Ltd., and Kanomax equipment (WPS 100XP) were used.

  As shown in FIG. 4, it is known that the dust particles having a particle size of 0.1 μm or less have a sharp Brownian motion, so that the increase in the count of the dust particles reaches a peak (in the vicinity of the particle size of 0.1 μm). It is said to be the maximum). However, in FIG. 4, Δ is a value when using a natural rubber polyisopropylene (PI) as the manual work glove 44, an aluminum (Al) bellows as the circulation duct 47, and □ is a manual work. Values when polyethylene glove 44 is made of polyethylene (PE), a bellows made of Al is used as circulation duct 47, ○ is made of polyethylene as glove 44 for manual work, and polyvinyl chloride (PVC) is used as circulation duct 47 It is a value when using the product made from. Considering FIG. 4 together, the cleanliness obtained by the above clean unit using the HEPA filter using glass fiber as the filter medium as the active dust filter 45a and the ULPA filter using polytetrafluoroethylene as the filter medium as the active dust filter 45b. Is concluded to exceed the ISO class-1 cleanliness level over the entire size of the dust particles. Therefore, the total number of all dust particles (dust, fungi, etc.) having a particle size of 0.01 μm or less is present within 0.03 or less in the work chamber 41 of this clean unit. It can be seen that almost no dust particles are present. Microbes are several μm to several tens of μm in protozoa, several μm in mold, about 1 μm in bacteria, about 0.3 μm in rickettsias, and virus ( viruses) is 0.01-0.2 μm, so that the presence of bacteria in the working chamber 41 can be completely suppressed without depending on a method such as sterilization. This completely sterile environment has been achieved for the first time by this clean unit.

Next explained is a clean unit according to the second embodiment of the invention.
FIG. 5 shows this clean unit. As shown in FIG. 5, in this clean unit, two active dustproof filters 45 a and 45 b having blowing power are attached in parallel to the upper surface of the work chamber 41, and these active dustproof filters 45 a and 45 b and the work chamber 41 are further mounted. Are connected so that the inside of the work chamber 41 can be maintained in a highly clean environment of class 0.0001 to class 0.1, for example. The active dustproof filters 45a and 45b have different minimum diameters of dust particles that can be removed, and the active dustproof filter 45b has a smaller minimum diameter of dust particles that can be removed than the active dustproof filter 45a. As the active dustproof filter 45a, for example, a HEPA filter using glass fiber as a filter medium is used, and as the active dustproof filter 45b, for example, a ULPA filter using polytetrafluoroethylene as a filter medium is used. The circulation duct 47 is branched into two branch portions 47a and 47b via a switching valve 49. The branch portion 47a is connected to the active dustproof filter 45a, and the branch portion 47b is connected to the active dustproof filter 45b. Connected with this ku.
Other configurations of the clean unit are the same as those of the clean unit according to the first embodiment.

Next, an example of the operation method of this clean unit will be described. Here, first, it is assumed that the inside of the work chamber 41 has a low cleanliness like a normal indoor environment.
First, the switching duct 49 is operated to connect the circulation duct 47 and the branching portion 47a, and the active dustproof filter 45a is operated for cleaning in a state where the circulation duct 47 and the branching portion 47b are blocked from each other. In this way, when the cleaning is performed and the cleanliness reaches a certain level, the switching valve 49 is switched to connect the circulation duct 47 and the branching portion 47b, and the circulation duct 47 and the branching portion 47a are blocked from each other, and the active dustproof filter. 45b is actuated for cleaning.

  As described above, according to the second embodiment, dust particles having a large particle diameter are removed by the active dust filter 45a, and after cleaning is performed to a cleanliness level, removal of dust particles having a smaller particle diameter is performed. Since the active dustproof filter 45b is used for cleaning, the active dustproof filter 45b is not clogged and the operation is performed as compared with the case where the active dustproof filter 45b is used for cleaning. The chamber 41 can be cleaned to a degree of cleanliness that can be reached by the active dust filter 45b. In addition, the life of the active dustproof filter 45b can be improved.

Next explained is a clean unit according to the third embodiment of the invention.
FIG. 6 shows this clean unit. As shown in FIG. 6, in this clean unit, an active dustproof filter 45 having a blast power and a circulation duct 47 are attached to a work chamber 41, and the inside of the work chamber 41 is, for example, about class 0.01 to class 1 Can be maintained in a highly clean environment. In this case, gate valves 50 a and 50 b that can be opened and closed independently of each other are attached above and below the active dust filter 45. An active dustproof filter 45 is attached to the upper surface of the work chamber 41 via a gate valve 50a, and a circulation duct 47 is connected to the active dustproof filter 45 via a gate valve 50b. The gate valves 50a and 50b may or may not be provided integrally with the active dustproof filter 45 in advance.
Other configurations of the clean unit are the same as, for example, the clean unit of the first embodiment.

Next, an example of the operation method of this clean unit will be described. Here, first, it is assumed that the inside of the work chamber 41 has a low cleanliness like a normal indoor environment.
First, cleaning is performed by operating the active dustproof filter 45 with both the gate valves 50a and 50b opened. When the cleanliness of the work chamber 41 reaches the desired level, the gate valves 50a and 50b are closed to shut off the active dust filter 45 and the work chamber 41, and then the operation of the active dust filter 45 is stopped. . By doing so, it is possible to prevent contamination due to dust particles being detached from the active dustproof filter 45 at the time of stopping and flowing back into the work chamber 41.

FIG. 7 shows a case where the active dustproof filter 45 is operated to clean the work chamber 41, and then the gate valve 50a, 50b is closed and then the operation of the active dustproof filter 45 is stopped. The result of having measured the time-dependent change of the cleanliness of the working chamber 41 with respect to the case where the operation of the active dustproof filter 45 is stopped without closing any 50b is shown. From FIG. 7, when the operation of the active dustproof filter 45 is stopped without closing the gate valves 50a and 50b, the count of dust particles increases rapidly with time, whereas the gate valve 50a When the operation of the active dustproof filter 45 is stopped after closing both of 50b and 50b, it can be seen that the increase in the count of dust particles is extremely effectively suppressed. This is because the backflow of dust particles from the active dust filter 45 to the working chamber 41 can be prevented by stopping the operation of the active dust filter 45 after closing both the gate valves 50a and 50b.
As described above, according to the third embodiment, it is possible to effectively prevent back-contamination of the work chamber 41 after the operation of the active dustproof filter 45 is stopped, and the work chamber 41 can be completely consumed without energy. High cleanliness can be maintained.

Next explained is a clean unit according to the third embodiment of the invention.
FIG. 8 shows this clean unit. As shown in FIG. 8, in this clean unit, a gas cylinder B is connected to the working chamber 41 via a gas supply pipe P in addition to the same configuration as the clean unit according to the fourth embodiment. The gas cylinder B is filled with an inert gas such as a rare gas or a nitrogen gas. Although not shown, a valve that can be controlled from the outside is provided in the middle of the gas supply pipe P. When this valve is opened, an inert gas can be introduced into the working chamber 41 from the gas cylinder B. It can be done. However, the supply of the inert gas to the working chamber 41 may be performed by another method without using the gas cylinder B. The work chamber 41 is provided with a leak valve V. By opening the leak valve V, the work chamber 41 can be opened to the atmosphere.

Next, an example of the operation method of this clean unit will be described. Here, first, it is assumed that the inside of the work chamber 41 has a low cleanliness like a normal indoor environment.
First, cleaning is performed by operating the active dustproof filter 45 with both the gate valves 50a and 50b opened. When the cleanliness of the work chamber 41 reaches the desired level, the gate valves 50a and 50b are closed to shut off the active dust filter 45 and the work chamber 41, and then the operation of the active dust filter 45 is stopped. . Next, the valve provided in the middle of the gas supply pipe P is opened, and at the same time, the leak valve V is opened, an inert gas is introduced from the gas cylinder B into the work chamber 41, and the internal air is pushed out from the leak valve V to the outside. Thus, the air inside the working chamber 41 is replaced with the inert gas.
According to the fourth embodiment, not only can the back-contamination of the working chamber 41 after the operation of the active dustproof filter 45 is stopped effectively prevented, but the air inside the working chamber 41 is replaced with an inert gas. Thus, the non-oxygen atmosphere can be obtained, so that the work chamber 41 can be maintained in a non-oxygen atmosphere with high cleanliness. Therefore, growth of a semiconductor thin film or the like by various methods such as coating or other various processes can be performed while preventing contamination by dust particles and oxidation by oxygen.

Next explained is a connected clean unit according to the fifth embodiment of the invention.
FIG. 9 shows a connected clean unit in which one or more of the clean units according to the first to fourth embodiments are connected. As shown in FIG. 9, in this coupled clean unit, clean units 121 to 128 that can be connected in three directions are coupled via a transfer box 129. In this case, the clean units 122 to 127 are connected in a loop arrangement.

  The work performed in each of the clean units 121 to 128 is, for example, as follows. First, the clean unit 121 is a storage unit, in which a sample storage (for example, a wafer cassette 130 containing a substrate) is installed, and the transfer box 129 on the right side surface that is not used for connection is used as a sample insertion port. The rear transfer box 129 is an emergency sample outlet. The clean unit 122 is a chemical unit, and a chemical pretreatment system 131 is installed to perform chemical pretreatment. The clean unit 123 is a resist process unit, and a spin coater 132 and a developing device 133 are installed to perform resist coating and development. The clean unit 124 is a lithography unit, and an exposure apparatus 134 is installed, and a transfer box 128 on the right side surface not used for connection is an emergency sample outlet. The clean unit 125 is a growth / metallization unit. The electrochemical device 135 and the microreactor system 136 are installed, and the transfer box 128 on the right side surface not used for connection is an emergency sample outlet. The clean unit 126 is an etching unit, and an etching apparatus 137 is installed. The transfer box 129 on the back surface of the clean unit 126 is connected to the transfer box 129 on the back surface of the clean unit 123 via a relay box 138. The clean unit 127 is an assembly unit in which a microscope 139 and a prober 140 are installed. The clean unit 128 is a scanning probe microscope (SPM) observation unit. A desktop STM 141 and a desktop AFM 142 are installed, and a transfer box 129 on the right side surface that is not used for connection is a sample outlet, and a transfer on the back surface that is also not used for connection. Box 129 is an emergency sample outlet. The spin coater 132 of the clean unit 123, the exposure device 134 of the clean unit 124, the electrochemical device 135 and microreactor system 136 of the clean unit 125, the etching device 137 of the clean unit 126, the prober 140 of the clean unit 127 are connected to the power supply 143. Power is supplied. The electrochemical device 135 of the clean unit 125 is connected to the electrochemical device controller 145 by a signal cable 144 and is controlled by the electrochemical device controller 145. Further, the observation images obtained by the microscope 139 of the clean unit 127, the desktop STM 141 of the clean unit 128, and the desktop AFM 142 can be displayed on the liquid crystal monitor 146.

  In the connected clean unit shown in FIG. 9, for example, a sample (for example, a semiconductor wafer) is stored in the working room of the portable clean unit 200 which is made portable by miniaturizing any one of the clean units according to the first to fourth embodiments. The transfer box of the portable clean unit 200 is attached to and connected to the sample outlet of the clean unit 128. In this state, the sample is transported from the clean unit 200 to the clean unit 128 via the transfer box 92 and observed by the desktop STM 141 or the desktop AFM 142.

  According to the fifth embodiment, the following many advantages can be obtained. In other words, almost all processes that are normally performed using a group of equipment installed in a huge clean room, such as chemical pretreatment, resist coating, exposure, development, growth / metallization, etching, probing, surface observation, etc. By adopting a loop arrangement or the like in a connected clean unit in which clean units that enclose a local space are connected, it can be realized in a simple and compact room in a normal laboratory scale without using a clean room.

Next, a sixth embodiment of the present invention will be described. In the sixth embodiment, a case where a solar cell as shown in FIG. 10 is manufactured will be described.
First, the configuration of this solar cell will be described.
10A, B and C show this solar cell. Here, FIG. 10A is a front view, FIG. 10B is a back view, and FIG. 10C is a side view. As shown in FIGS. 10A, 10B, and 10C, in this solar cell, an anode electrode 1151 and a cathode electrode 1152 are spirally sandwiched by a pn junction 1153 composed of a p-type semiconductor layer and an n-type semiconductor layer. It is formed and has a thin disk shape as a whole. These p-type semiconductor layer and n-type semiconductor layer may be inorganic semiconductors or organic semiconductors. Reference numeral 1155 denotes an extraction electrode for the cathode electrode 1152.

FIG. 11 schematically shows the detailed structure of this solar cell. In FIG. 11, reference numeral 1191 denotes a p-type semiconductor layer, and 1192 denotes an n-type semiconductor layer. As shown in FIG. 11, an insulating film 1193 made of various insulators such as a resin is provided at a portion where the anode electrode 1151 and the cathode electrode 1152 are back to back. The electrodes 1152 are electrically insulated from each other. In this case, the cathode electrode 1152 is a full-surface electrode and is in ohmic contact with the n-type semiconductor layer 1192, whereas the anode electrode 1151 has n elongated microscopic pieces separated from each other in the thickness (W) direction of the disk. It consists of anode electrodes 1511-1 to 1511-n. These fine anode electrodes 1151-1 to 1151-n have widths W ₁ , W ₂ ,..., W _n , respectively, which may be the same or different.

The band gap E _g of the p-type semiconductor layer 1191 and the n-type semiconductor layer 1192 gradually decreases in n steps (n ≧ 2) in the thickness direction of the disk from the light incident surface, and from the light incident surface side. In this order, E _g1 , E _g2 ,..., E _gn (E _g1 > E _g2 >...> E _gn ). A region of the p-type semiconductor layer 1191 and the n-type semiconductor layer 1192 in which the band gap E _g is E _gk (1 ≦ k ≦ n) is referred to as an E _gk region. The p-type semiconductor layer 1191 in the E _gk region and the minute anode electrode 1151-k are in ohmic contact. These E _gk regions may be integrated or separated from each other. A structure in which an E _gk region is sandwiched between the minute anode electrode 1151-k and the cathode electrode 1152 constitutes a minute solar cell, and the n number of minute solar cells using the cathode electrode 1152 as a common electrode constitutes this solar cell. Is configured.

E _gk can be set as follows. For example, the wavelength is divided into n sections in the entire wavelength range of the AM1.5 sunlight spectrum or its main wavelength range (including a portion with a high incident energy). These sections are numbered in order from the short wavelength side (high energy side) 1, 2,..., N, and E _gk is selected to be equal to the minimum photon energy of the kth section. In this way, when a photon having photon energy in the kth section is incident on the E _gk region, an electron-hole pair is generated and photoelectric conversion is performed. In this case, the depth from the light incident surface to the E _gk region is selected so that photons having the photon energy in the k-th section reach each E _gk region and are sufficiently absorbed. As a result, the sunlight incident on the light incident surface of the solar cell is first incident on the E _g1 region, the photon energy of E _g1 or higher in the spectrum is absorbed and photoelectrically converted, and then the E _g2 region. And the photon energy of which is greater than E _{g2 and} smaller than E _g1 is absorbed and photoelectrically converted, and finally enters the E _gn region and the photon energy of the spectrum is greater than E _gn and E Things smaller than _gn-1 are absorbed and photoelectrically converted. As a result, light in almost the entire solar spectrum or in the main wavelength range can be used for photoelectric conversion.

Each E _gk can be set by changing the composition of the semiconductor constituting each E _gk region. Specifically, each E _gk region is composed of another kind of semiconductor. Some specific examples of using an inorganic semiconductor are as follows. In the simplest case where n = 2, for example, the E _g1 region is composed of GaAs (E _g = 1.43 eV) and the E _g2 region is composed of Si (E _g = 1.11 eV). When n = 3, for example, the E _g1 region is GaP (E _g = 2.25 eV), the E _g2 region is GaAs (E _g = 1.43 eV), and the E _g3 region is Si (E _g = 1). .11 eV). When n = 4, for example, the E _g1 region is GaP (E _g = 2.25 eV), the E _g2 region is GaAs (E _g = 1.43 eV), and the E _g3 region is Si (E _g = 1). .11 eV), the E _g4 region is composed of Ge (E _g = 0.76 eV). Furthermore, it is also possible to configure the E _gk region in the case of n to 10 using only GaInN _x As _1-x or GaInN _x P _1-x and controlling x. In addition, the E _gk region may be formed using II-VI group compound semiconductors that are known to exhibit large bowing when Te is included.

This solar cell can be manufactured, for example, as follows.
First, a thin flat tape-shaped resin base film having a predetermined width, for example, is wound around a roller, and a plurality of band gaps differing from each other by coating or vapor deposition as needed on one surface of the resin base film. A plurality of types of p-type semiconductor layers are formed in the same manner, and then a plurality of types of p-type semiconductor layers are formed in the same manner. Next, a metal for an anode electrode is formed in the same manner to form anode electrodes 1151-1 to 1151-n. After forming the insulating material in the same manner to form the insulating film 1193, the metal for the cathode electrode is formed in the same manner to form the cathode electrode 1152, and then the resin-made base film with the laminated film is formed. Is taken up by a roller-shaped extraction electrode 1155.
In order to prevent the resin base film from being entrained when each of the layers formed by coating or vapor deposition is formed in a spiral shape, the back surface of the resin base film was heated to a high temperature immediately before entrainment. The resin base film is peeled off by pressing a roller or irradiating the back surface with light.

In the sixth embodiment, the above-described processes such as coating and vapor deposition are performed in any one of the clean units according to the first to fourth embodiments. At this time, the inner product dS · V of the area vector dS of the coating surface or the vapor deposition surface and the macro wind flow vector V is set to be zero. By doing so, processes such as coating and vapor deposition can be performed in an extremely high cleanliness environment, and a solar cell can be manufactured with a high yield.
According to the sixth embodiment, for example, a conventional amorphous Si solar cell cannot use light having a photon energy smaller than 1.12 eV in the sunlight spectrum, but by designing the E _gk region. In addition, the light of the entire solar spectrum or the main part can be used for photoelectric conversion, and a solar cell with extremely high photoelectric conversion efficiency can be manufactured with a high yield.

As mentioned above, although embodiment of this invention was described concretely, this invention is not limited to the above-mentioned embodiment, The various deformation | transformation based on the technical idea of this invention is possible.
For example, the numerical values, materials, shapes, arrangements, and the like given in the above-described embodiments are merely examples, and different numerical values, materials, shapes, arrangements, and the like may be used as necessary.

It is a front view which shows the clean unit by 1st Embodiment of this invention. It is the upper side figure and side view of the clean unit by 1st Embodiment of this invention. It is a basic diagram which shows the example of the measurement result of the cleanliness obtained by the clean unit by 1st Embodiment. It is a basic diagram which shows the example of the measurement result of the cleanliness obtained by the clean unit by 1st Embodiment. It is a front view which shows the clean unit by 2nd Embodiment of this invention. It is a front view which shows the clean unit by 3rd Embodiment of this invention. It is a basic diagram for demonstrating the maintenance effect of the high cleanliness by the clean unit by 3rd Embodiment of this invention. It is a front view which shows the clean unit by 4th Embodiment of this invention. It is a basic diagram for demonstrating the usage example of the clean unit by 1st-4th embodiment of this invention. It is the front view, back view, and side view which show the solar cell manufactured by 6th Embodiment of this invention. It is a basic diagram which shows the solar cell manufactured by 6th Embodiment of this invention.

Explanation of symbols

41 ... work chamber, 42, 43 ... transfer box, 45, 45a, 45b ... active dust filter, 47 ... circulation duct, 50a, 50b ... gate valve, P ... gas supply pipe, B ... gas cylinder, V ... leak valve

Claims (3)

A method for operating a clean unit having a circulation type filter and capable of maintaining a clean environment,
In the circulation type filter, at least a part of the first dust filter having blowing power and the minimum diameter of the removable dust fine particles are the first diameter. A second dust filter having a second particle size smaller than the particle size of 1 and having blowing power,
The first dust filter and the second dust filter are provided in parallel to the clean unit;
The first dust filter and the second dust filter are configured to be switchable,
After removing dust particles larger than the first particle size by the first dust filter, the dust particles larger than the second particle size are removed by switching from the first dust filter to the second dust filter. A method for operating a clean unit, characterized in that 2. The clean unit according to claim 1, wherein dust particles are removed by the first dust filter and the second dust filter and then air is replaced by introducing an inert gas into the working chamber. Driving method. 2. The clean according to claim 1, wherein the first dust filter is a HEPA filter using glass fiber as a filter medium, and the second dust filter is a ULPA filter using polytetrafluoroethylene as a filter medium. Unit operation method.

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