JP2005329406A - Sterilization and cleaning method for enclosed space including germs and enclosed space with sterilization and cleaning function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a device for cleaning an enclosed space capable of effectively capturing and removing a gaseous contaminant with particulate matters including germs in the air and microorganisms by extending a freely workable effective area. <P>SOLUTION: In a cleaning device having the cleaning function of using an ultraviolet ray source 2, a photoelectron emitting material 3 and/or a photocatalyst 15 for the enclosed space 1 including the germs in the air and the microorganisms, a sterilization and cleaning device provided with the ultraviolet ray source 2 in the center, the photoelectron emitting material 3 and/or the photocatalyst 15 is installed on the floor 14 of the enclosed space or on the under part of the floor 14 via a parting plate. The sterilization and cleaning device can be used in combination with the cleaning by an ion exchange fiber, and a sterilizer lamp can be used as the ultraviolet ray source. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to cleaning of a sealed space containing fungi and microorganisms, and in particular, a safety cabinet, a clean box, a valuable storage, a wafer storage, a pass box, a transport box, a valuable transport sealed space, an interface, and an apparatus. The present invention relates to a method for cleaning a sealed space such as a delivery device and a pass box and a device therefor.

The prior art will be described below with reference to an example of clean air in a semiconductor manufacturing factory.
The space in a clean room has been conventionally cleaned by a method using a HEPA or ULPA filter. This method is effective for cleaning a conventional clean room, clean goose, clean bench, etc., and has been widely put into practical use. However, the removal of fine particles by this method has the following problems because it is necessary in principle to feed a gas containing fine particles to the filter.
(1) Since forced ventilation is performed, fine particles may be generated. In this case, there is a limit to the degree of cleanliness (creation of an ultra-clean space).
(2) Since the pressure loss is high, the operation cost is high.
(3) Recently, gaseous substances such as boron are generated depending on how the filter is used, and it is said that the filter becomes a secondary contamination source and that there is a limit to the performance of collecting ultrafine particles.

Against such a background, the present inventors have already proposed a method and apparatus for generating photoelectrons by irradiating the photoelectron emitting material with ultraviolet rays to clean the space (for example, Japanese Patent Publication No. 3). No. -5859, Japanese Patent Publication No. 6-34941, Japanese Patent Publication No. 7-110342, Japanese Patent Publication No. 6-74909, Japanese Patent Publication No. 6-74910, Japanese Patent Publication No. 8-211, and Japanese Patent Publication No. Hei 6-277558.
Although these methods and apparatuses can be implemented with sufficient effects depending on the field of use, apparatus type, structure, shape, and required performance, there is still room for improvement.
Next, improvements will be described by taking the prior art as an example.
A conventional technique will be described by taking an example of air cleaning in a wafer storage (stocker) by removing fine particles using photoelectrons in a semiconductor factory (Japanese Patent Laid-Open No. Hei 6-277558).

Air cleaning in a wafer storage (wafer storage stocker) of a semiconductor factory will be described with reference to the configuration diagram shown in FIG. Air cleaning of the wafer storage 1 is performed by an ultraviolet lamp 2 installed on one side of the wafer storage 1, an ultraviolet reflection surface 12, a photoelectron emission material 3, an electric field for photoelectron emission, and an electrode 4 for collecting charged fine particles. The charged fine particle comprising the electrode 13 for surely collecting the charged fine particle that has been leaked (passed through) without being collected by the fine charge / collector (A) and the charged / collector (A). Implemented from the collection unit (B).
That is, the fine particles (particulate matter) 6 in the wafer storage 1 are charged by the photoelectrons 5 emitted from the photoelectron emitting material 3 irradiated with ultraviolet rays from the ultraviolet lamp 2 to become charged fine particles 7, and the charged fine particles 7. Is collected 8 by the charged particulate collection material (electrode) 4 (charge / collection portion of particulates, A), and the treated space portion (cleaning space portion, C) where the wafer exists is highly purified. On the other hand, the charged fine particles that have passed without being collected by the charge / collection part (A) of the fine particles during long-time operation or in an unsteady state are not connected to the electrode behind the charge / collection part (A). 13 is surely collected.

Reference numerals 9a, 9b, and 9c denote air flows in the storage. That is, since the air that has moved to the charging / collecting part (A) of the fine particles is heated by the irradiation of the ultraviolet lamp, an ascending air current is generated and moves in the storage 1 or as indicated by arrows 9a, 9b, 9c. Due to the movement of the air, the fine particles 6 in the storage are effectively moved to the charging / collecting part A of the fine particles, so that the inside of the storage 1 is effectively cleaned.
In this way, fine particles (particulate matter) 6 in the wafer storage 1 are collected and removed, the wafer storage becomes ultra-clean air, and contamination of the wafer 11 is prevented. In the case where such a particle charging / collecting part (A, B) is installed on one side of the wafer, the cleaning space part (C), that is, the storage area (working effective area C) is reduced. was there.

On the other hand, with the recent development of advanced industries, control of gaseous substances shared by fine particles has become important.
This is because in the semiconductor industry, the quality and precision of products will continue to increase, and along with this, gaseous substances will be involved as contaminants. In other words, the removal of fine particles has been sufficient in the past, but in the future, control of gaseous substances (gaseous harmful components) will become important. In the conventional clean room filter, only fine particles are removed, and gaseous harmful components from the outside air are introduced into the clean room without being removed.
In other words, in the clean room, as particulates (particulate matter), exhaust gas of automobiles and consumer products that are not collected and removed by conventional dust filters (eg, HEPA, ULPA filters) and are introduced into the clean room. Hydrocarbons (HC), acidic gases such as NOx, SOx, KCl, and HF due to degassing from widely used polymer resin products, basic (alkaline) such as NH ₃ and amine Gaseous substances such as gases are problematic as gaseous harmful components.

Among these, H.H. C is a gaseous harmful component, and extremely low concentrations in normal air (indoor air and outside air) cause contamination. Therefore, it is necessary to remove C.
Also, recently, degassing from polymer resins of clean room components and equipment used (eg, wafer pass box) has been It is a problem as a source of C (Japan Machinery Federation, 1994 report, March 1995, p. 41-49, 1995).
These gaseous substances are also problematic when they are generated during work in a clean room. That is, in a normal clean room as a cause of the gaseous substance, the gaseous substance introduced from the outside air (the gaseous substance in the outside air is introduced because the gaseous substance cannot be removed by the filter in the clean room). Since the gaseous substance generated in the clean room is added, the gaseous substance in the clean room has a higher concentration than the outside air and contaminates the wafer base material and the substrate.

That is, if the above-mentioned contaminants (fine particles, gaseous harmful components) adhere to the wafer, semi-finished product, or product substrate surface, the fine particles cause a circuit (pattern) disconnection or short circuit on the substrate surface and cause a defect. Moreover, as a gaseous substance, (a) H.H. When C adheres to the wafer (substrate) surface, it causes an increase in contact angle. C affects the affinity (familiarity) between the substrate and the resist. If the affinity is deteriorated, the film thickness of the resist is adversely affected, or the adhesiveness between the substrate and the resist is adversely affected (Air Cleaning, Vol. 33, No. 1, p. 16-21, 1995). (B) SOx causes an oxide film insulation failure. (C) NH ₃ brings about production of ammonium salt and causes clouding (unresolved resolution) on the wafer (Rearice, latest technology course, data collection, semiconductor process seminar, October 29, 1996, p. 15) -25, 1996).
For these reasons, these gaseous pollutants reduce the productivity (yield) of semiconductor products.

In particular, the above-mentioned gaseous substance as a gaseous harmful component is used due to the above-mentioned generation, and recently, since the circulation of clean room air is increased from the viewpoint of energy saving, the concentration of the gaseous substance in the clean room is concentrated, The concentration is considerably higher than that of the outside air, and it adheres to the base material and the substrate and contaminates the surface. The degree of contamination can be expressed by the contact angle of the base material or the substrate. If the contamination is severe, the contact angle is large. Even if a base material or a substrate having a large contact angle is formed on the surface thereof, the adhesion strength of the film is weak (unfamiliar), resulting in a decrease in yield.
Here, the contact angle is a contact angle of wetting with water and indicates the degree of contamination of the substrate surface. That is, when hydrophobic (oil-based) contaminants adhere to the substrate surface, the surface repels water and becomes difficult to wet. This increases the contact angle between the substrate surface and the water droplets. Therefore, if the contact angle is large, the degree of contamination is high. Conversely, if the contact angle is small, the degree of contamination is low.

In particular, since clean room air is circulated and used recently in terms of energy saving, gaseous harmful components in the clean room gradually increase and contaminate the base material and the substrate.
As described above, the future cleaning technology requires not only fine particles but also simultaneous control of fine particles and gas depending on the application destination (14th Aerosol Science and Technology Research Conference, p.157-159, 1997).
Against such a background, the present inventors have proposed a cleaning method using the above-mentioned photoelectrons for fine particle (particulate matter) contamination, while photocatalysts and ion exchange are used for contamination by gaseous contaminants. A cleaning method using fibers is proposed as exemplified below.

1) Cleaning method using a photocatalyst; JP-A-9-168722 and JP-A-9-205046.
2) Cleaning method using ion exchange fiber; Japanese Patent Publication No. 5-67325 and Japanese Patent Publication No. 6-24626.
3) Cleaning method by simultaneous control of fine particles and gas by the combination of the above methods; Japanese Patent Publication No. 1-166864, Japanese Patent Publication No. 6-87997, Japanese Patent Application Laid-Open No. 7-57981, Japanese Patent Application No. 7-352183.
These methods and devices are effective depending on the type of application destination, the shape and structure of the device, the method of storing the base material and the substrate in the space, etc. There was room for improvement depending on the method.
Although these methods and apparatuses can be implemented with sufficient effects depending on the field of use, apparatus type, structure, shape, and required performance, there is still room for improvement.
JP-A-6-277558 JP 7-57981 A JP-A-9-168722

  In view of the above-mentioned known facts, the present invention can widen the effective area in which work can be performed freely, and depending on the application destination (required performance), fine particles containing airborne bacteria and microorganisms and gaseous pollutants shared therewith It is an object of the present invention to provide a method and apparatus for cleaning an enclosed space that can be quickly and effectively collected and removed, and sterilized and cleaned.

In order to solve the above problems, in the present invention, in a method of sterilizing and cleaning a sealed space containing airborne bacteria and microorganisms by irradiating a photoelectron emitting material and / or a photocatalyst with light from an ultraviolet light source, The photoelectron emitting material and / or photocatalyst is irradiated with light from an ultraviolet light source on the floor surface or at a lower portion of the floor surface via a partition plate, and sterilized and cleaned. The air is sent upward from the entire floor surface.
Further, in the present invention, in a sealed space containing airborne bacteria and microorganisms having a cleaning function using an ultraviolet light source and a photoelectron emitting material and / or a photocatalyst, the floor surface of the sealed space or a partition plate is used. In the lower part, a sterilizing and cleaning device provided with a photoelectron emitting material and / or a photocatalyst centered on an ultraviolet ray source is installed, and the cleaning device is provided with an opening on the entire floor surface. It is set as the structure which has.
In the cleaning, cleaning with ion exchange fibers may be combined, and the cleaning device may have a configuration in which the outer periphery is covered with a heat insulating material and is insulated from the outside and the outer peripheral path.

In this invention, it can be set as the pass box with a cleaning function which uses the said enclosed space with a cleaning function for a pass box, has an accommodating part in the upper part, and has a sterilization cleaning apparatus in the lower part.
Further, in the present invention, in the pass box with a cleaning function having a storage part in the upper part and having a sterilization cleaning apparatus using an ultraviolet light source and a photoelectron emitting material in the lower part, the sterilization cleaning apparatus has a lower ultraviolet light source. And a photoelectron emitting material, a charged portion having an electrode material for setting an electric field, and a collecting portion that collects charged fine particles above the charged portion, and the collected gas is moved upward from below. In addition to having an opening that can be moved over the entire surface, an outer circumferential path for circulating gas from the top of the storage part to the gas cleaning device is provided.
In the pass box, the cleaning device can be a unit that can be removed by integrating the charging unit and the collecting unit, and the outer circumferential path has a side wall surface of the pass box as a double wall structure. Can be provided on the entire surface.
Further, the pass box can have two power sources for supplying the cleaning device, a battery and a commercial power source provided in the box.

According to the present invention, the following effects can be achieved.
1) In the cleaning of a sealed space using an ultraviolet ray source and a photoelectron emitting material and / or a photocatalyst, the ultraviolet ray source and the photoelectron emitting material and / or the photocatalyst are placed on the floor surface of the cleaning space in the sealed space or via a partition plate. By installing in the lower part of the floor,
(1) The work surface on the floor can be used over the entire surface (the effective work area is widened).
(2) Since the upward diversion generated from the ultraviolet lamp could be used rationally, the sealed space could be effectively cleaned.
(3) By simultaneously using the photoelectron emitting material and the photocatalyst, a simultaneous removal space for gas and particles was effectively obtained.

The present invention has been invented based on the following five findings.
1) The space has been cleaned by a method using a filter. This method has the following problems in principle because forced air is supplied to the filter by a fan.
(A) Generation of particulate matter or gaseous matter by forced ventilation.
(B) Since the clean air is spatially and forcibly ventilated (circulated), the articles (eg, wafers) stored in the space are sequentially exposed to the air flow, thereby accelerating contamination.
(C) Since forced ventilation is performed, the pressure loss increases and the operating cost increases as the cleanliness increases.
(D) In normal air (outside air), gaseous harmful components such as acidic gases such as NOx, SOx and HCl, alkaline gases such as ammonia and amines, and organics called hydrocarbons (HC) Gases are present and the present filters cannot collect these gaseous harmful components, so these harmful gases are introduced into the space and become a new pollution source (contamination cause) in the space.

2) In contrast to the above, the cleaning method using ultraviolet rays (the above-described method using photoelectrons, the method using a photocatalyst) proposed by the present inventors is based on a slight temperature difference caused by ultraviolet irradiation, and the gas in the sealed space Fluidized, so that the pollutants in the space are sequentially sent to the processing space of the pollutants for effective treatment ((1) Aerosol Research, Vol. 8, No. 4, p315 324, 1993, (2) Proceedings of 12th ISCC in Yokohama, p. 117-122, 1994, (3) JP-A-9-168722, (4) JP-A-9-205046).
3) In advanced industrial fields such as semiconductors and liquid crystals, removal of particulate matter has been sufficient in the past, but due to high quality and refinement of products (more expensive products are denser, that is, finer In the future, it will be strongly influenced by gaseous substances.

Therefore, a clean room air concentration (very low concentration such as a ppb level) level that has not been a problem in the past has been found. It has become necessary to control and remove gaseous pollutants such as C, SO ₂ , HCl, HF, and NH ₃ (“The 39th Annual Meeting of the Japan Society of Applied Physics”, p86, 1992 Spring, “Air Cleaner” 33, No. 1, p16-21, 1995, “Ultra Clean Technology” Vol.6, p29-35, 1994).
This is because the presence of these gaseous pollutants has been shown to significantly reduce yield (productivity).
(A) Future clean rooms in advanced industries will require simultaneous removal of particulate matter (fine particles) and gaseous harmful components.
(B) The above-mentioned gaseous harmful components are generated from work in clean rooms and from clean room components and equipment, and even if these generated gases are extremely low in concentration, the clean room is closed and confined. (Recently, clean rooms have a high rate of air circulation in terms of energy saving), and the concentration gradually increases and adheres to the wafer, glass substrate, and base material in the clean room, and has an adverse effect.

The generation of harmful gas in the clean room Next, C will be described as an example.
In a clean room environment where at least a part is composed of an organic substance (polymer resin), an extremely small amount of organic gas (HC) is generated from the organic substance, and the contents in the clean room space (such as wafers and glass substrates) Contaminating raw materials and semi-finished products).
That is, in a clean room space, organic substances (eg, plastic containers, packing materials, sealing materials, adhesives, wall materials, etc.) are used at least in part, and a very small amount of organic gas is generated from the organic substances. To do.
For example, siloxane is generated from the sealing material, and phthalate is generated from the plastic material that is the material of the storage container.

H. The degree of contamination of the substrate surface when C adheres (adsorbs) to a substrate such as a wafer can be represented by a contact angle (below). H. The problem of the substrate contaminated with C will be described with a specific example. Contamination of the wafer substrate (valuable) by C affects the affinity (familiarity) between the substrate and the resist. When the affinity is deteriorated, the resist and the film thickness are affected, or the adhesion between the substrate and the resist is affected, resulting in a decrease in quality and a yield.
The contact angle is a contact angle of wetting with water and indicates the degree of contamination of the substrate surface. That is, when a hydrophobic (oil-based) substance is attached to the substrate surface, the surface repels water and becomes difficult to wet. This increases the contact angle between the substrate surface and the water droplets. Therefore, if the contact angle is large, the degree of contamination is high. Conversely, if the contact angle is small, the degree of contamination is low.
(C) Also in the consumer field, as seen in the thick building syndroad, it is necessary to remove these organic gases (for example, aldehyde, chlorine-containing HC), acid gas, and basic gas at the same time. ing.

4) In fields where various fungi and microorganisms in hospitals, food industry, medicine, etc. are problematic, in the case of a cleaning method using a filter, on the filter or in the circulation system (filter and fan, its route, and its surroundings) There are problems such as secondary contamination due to the growth of various fungi and microorganisms.
5) Cleaning the sealed space using an ultraviolet ray source and a photoelectron emitting material and / or a photocatalyst is performed by removing the ultraviolet ray source, the photoelectron emitting material and / or the photocatalyst on the floor surface of the cleaning space in the sealed space and / or a partition plate. By installing in the lower part of the floor surface through the space, the space is effectively super-cleaned.
This is because the rising airflow generated by the ultraviolet irradiation acts effectively. That is, to use the ascending air well (reasonably) is an important point for effectively performing the cleaning method using ultraviolet rays.

Further, in the field where ionic substances such as NH ₃ , SOx, NOx, HCl, and HF are problematic, when ion exchange fibers are added to the method using photoelectrons and / or photocatalysts, the ionic substances are simultaneously used. It is removed and an ultra-clean space is effectively obtained.
In particular, when using a photocatalyst, if there is a large amount of the ionic substance coexisting, problems may occur due to adhesion of the ionic substance or its product to the surface of the photocatalyst. Preferably it is done. For example, a product of an ionic substance (sulfate) adheres to the surface of the photocatalyst, resulting in performance degradation after a long operation.

Next, each structure in the cleaning of this invention is demonstrated.
First, the ultraviolet ray source essential for the configuration of the present invention will be described.
The ultraviolet ray source irradiates the photoelectron emitting material by the photoelectron method and / or the photocatalyst method by the photocatalyst in the cleaning of the present invention, and the operation of each is as described later.
As the ultraviolet ray source, a mercury lamp, a hydrogen discharge tube, a xenon discharge tube, a Lyman discharge tube, or the like can be used as appropriate. Examples of the light source include a sterilizing lamp, a black light, a fluorescent chemical lamp, a UV-B ultraviolet lamp, and a xenon lamp.
Among these, a sterilizing lamp (wavelength: 254 nm) is preferable because airborne fungi and microorganisms coexisting with the particulate matter have a sterilizing (sterilizing) action. That is, by using a sterilizing lamp as an ultraviolet ray source, a sterilizing action can be added simultaneously with the collection and removal of particulate matter and / or gaseous pollutants, which is preferable depending on the use destination (device type).

Next, the configuration of the cleaning means will be described.
1) Photoelectron method The photoelectron method is effective in removing particulate matter (fine particles) ((1) Aerosol Research, Vol. 8, No. 4, p.315-324, 1993, (2) Proceedings of the 12th ISCC in Yokohama p. 117-122, 1994). As the photoelectron method, those already proposed by the present inventors can be used as appropriate (for example, Japanese Patent Publication No. 6-74909, Japanese Patent Publication No. 8-211, Japanese Patent Publication No. 7-121369, Japanese Patent Publication No. 8-22393). No. publications).
The photoelectron emitting material may be any material as long as it emits photoelectrons upon irradiation with ultraviolet rays, and a material having a small photoelectric work function is preferable. From the aspect of effect and economy, Ba, Sr, Ca, Y, Gd, La, Ce, Nd, Th, Pr, Be, Zr, Fe, Ni, Zn, Cu, Ag, Pt, Cd, Pb, Al, Any of C, Mg, Au, In, Bi, Nb, Si, Ti, Ta, U, B, Eu, Sn, P, and W, or a compound, alloy, or mixture thereof is preferable. The above is used in combination. As the composite material, a physical composite material such as amalgam can also be used.

For example, the compounds include oxides, borides, and carbides. The oxides include BaO, SrO, CaO, Y ₂ O ₅ , Gd ₂ O ₃ , Nd ₂ O ₃ , ThO ₂ , ZrO ₂ , and Fe ₂ O _3. , ZnO, CuO, Ag ₂ O, La ₂ O ₃ , PtO, PbO, Al ₂ O ₃ , MgO, In ₂ O ₃ , BiO, NbO, BeO, etc., and borides include YB ₆ , GdB _6. , LaB ₅ , NdB ₆ , CeB ₆ , EuB ₆ , PrB ₆ , ZrB _{2, and the} like, and the carbides include UC, ZrC, TaC, TiC, NbC, WC, and the like.
Further, as the alloy, brass, bronze, phosphor bronze, an alloy of Ag and Mg (Mg is 2 to 20 wt%), an alloy of Cu and Be (Be is 1 to 10 wt%), and an alloy of Ba and Al are used. The alloy of Ag and Mg, the alloy of Cu and Be, and the alloy of Ba and Al are preferable. The oxide can also be obtained by heating only the metal surface in the air or oxidizing it with a chemical.

As yet another method, heating can be performed before use to form an oxide layer on the surface to obtain a stable oxide layer over a long period of time. As an example, an oxide film can be formed on the surface of an alloy of Mg and Ag in water vapor at a temperature of 300 to 400 ° C. The oxide thin film is stable over a long period of time.
These substances can be used in bulk (solid, plate-like) or added to an appropriate base material (support) (Japanese Patent Laid-Open No. 3-108698). For example, it can be added to the surface of an ultraviolet light transmissive substance or in the vicinity of the surface (Japanese Patent Publication No. 7-93098).
Any method may be used as long as photoelectrons are emitted by irradiation with ultraviolet rays.
For example, a method of coating on a glass plate, another method of embedding in the vicinity of the surface of a plate-like substance, or a method of adding another material on the plate-like substance. And a method using a mixture of an ultraviolet light transmissive substance and a substance that emits photoelectrons. Moreover, the addition can be suitably used such as a method of adding to a thin film, a method of adding to a net, line, granule, island, or band.

A method for adding a material that emits photoelectrons can be formed by coating or adhering to the surface of an appropriate material by a known method. For example, an ion plating method, a sputtering method, a vapor deposition method, a CVD method, a plating method, a coating method, a stamp printing method, and a screen printing method can be used as appropriate.
The thickness of the thin film may be any thickness as long as photoelectrons are emitted by irradiation with ultraviolet rays or radiation, and is generally 5 to 5,000 mm, and usually 20 to 500 mm. The base material can be used in a plate shape, a pleat shape, a cylindrical shape, a rod shape, a wire shape, a net shape, a fiber shape, a honeycomb shape, and the like, and the surface shape can be appropriately set to be uneven. Also, the tip of the convex portion can be sharp or spherical (Japanese Patent Publication No. 6-74908).

For the addition of the thin film to the base material, as already proposed by the present inventor, one type or two or more types of materials can be used in a single layer or in multiple layers. That is, a plurality of thin films can be used as appropriate (composite) to form a double structure or a multiple structure (JP-A-4-152296).
These optimum shapes and types of materials that emit photoelectrons when irradiated with ultraviolet rays, addition method, thin film thickness, device type, scale, shape, type of photoemission material, type of base material, electric field strength, Preliminary tests can be made and determined as appropriate in terms of how to apply, effects, and economy.
In the case of using the photoelectron emitting material added to the base material, the base material includes ceramic, clay, and a well-known metal material in addition to the above-described ultraviolet light transmissive material. Alternatively, the surface of the light source described later may be coated with the photoelectron emitting material (the light source and the photoelectron emitting material are integrated) (JP-A-4-243540).

It can also be integrated with a photocatalyst described later (Japanese Patent Application No. 8-132563). In this form, the photocatalyst can stabilize the photoelectron emitting material for a long period of time (can be removed even if there is an influencing substance on the photoelectron emitting material) and can remove coexisting gaseous pollutants. (Required performance) is preferable.
Generation of photoelectrons by irradiating the photoelectron emitting material with ultraviolet rays is effective when photoelectrons from the photoelectron emitting material are generated by forming an electric field (electric field) between the photoelectron emitting material (negative electrode) and an electrode (positive electrode) described later. To happen.
The method (structure) for forming an electric field can be appropriately selected depending on the shape, structure, application field, type of apparatus or expected effect (accuracy) of the charged portion. The strength of the electric field can be appropriately determined depending on the kind of addition to the photoelectron emitting material and the base material, and there is another invention of the present inventor about this. The strength of the electric field is generally 0.1 V / cm to 2 kV / cm.

Next, the electrode will be described.
In order to effectively generate photoelectrons from the photoelectron emitting material, the electrode is installed on the opposite side of the photoelectron emitting material (negative electrode), and an electric field is formed between the electrode and the electrode (positive electrode).
The electrode material and its shape may be any as long as the electric field can be formed. Any material can be used as long as it is a conductive material that does not generate impurities, and examples thereof include SUS, Cu—Zn, and W. The shape includes a plate shape, a pleat shape, a cylindrical shape, a rod shape, a line shape, a fiber shape, a net shape, and a honeycomb shape, and can be determined by appropriately conducting a preliminary test depending on the type, shape, and scale of the device and the photoelectron emitting material.

Next, a collection material (dust collection material) for collecting charged particulate matter will be described.
The collection material is used for the purpose of collecting / removing the charged particulate matter charged by the charged portion of the particulate matter in front of it.
The collecting material may be any material that reliably collects charged particulate matter, and any known charged particle collecting material can be used. Dust collecting plate, dust collecting electrode various electrode materials and electrostatic filter system in ordinary charging device are common, but the collection part itself such as steel wool electrode and tungsten wool electrode has a wool-like structure constituting the electrode. Things are also effective. Electric trek material can also be used suitably. Moreover, the method of collecting using the ion exchange filter (or fiber) which the inventor has already proposed is also effective (Japanese Patent Publication Nos. 5-9123 and 6-87997).

2) Photocatalyst method Photocatalyst removes ammonia, alkaline gas such as amine, acidic gas such as NOx, organic gas called hydrocarbon (HC) as a gaseous pollutant, especially organic gas among them. (15th Air Cleaning and Contamination Control Research Conference Preliminary Proceedings, p. 309-314, 1997).
As a method using a photocatalyst, those already proposed by the present inventor can be used as appropriate (for example, JP-A-9-168722 and JP-A-9-205046). The photocatalyst exhibits the photocatalytic action when the following photocatalyst material is irradiated with ultraviolet rays.
A photocatalyst is usually preferable because a semiconductor material is effective, easily available, and has good processability. From the aspect of effect and economy, Se, Ge, Si, Ti, Zn, Cu, Al, Sn, Ga, In, P, As, Sb, C, Cd, S, Te, Ni, Fe, Co, Ag, Any of Mo, Sr, W, Cr, Ba, and Pb, or a compound, alloy, or oxide thereof is preferable. These are used alone or in combination of two or more.

For example, the elements Si, Ge, Se, AlP as compounds, AlAs, GaP, AlSb, GaAs , InP, GaSb, InAs, InSb, CdS, CdSe, ZnS, MoS 2, WTe 2, Cr 2 Te 3, MoTe , Cu ₂ S, WS ₂ , oxides include TiO ₂ , Bi ₂ O ₃ , CuO, Cu ₂ O, ZnO, MoO ₃ , InO ₃ , Ag ₂ O, PbO, SrTiO ₃ , BaTiO ₃ , Co ₃ O _4. , Fe ₂ O ₃ , NiO, and the like.
For immobilization of the photocatalyst, a known addition method such as a vapor deposition method, a sputtering method, a sintering method, a sol-gel method, a coating method, a baking method, or the like can be appropriately used for an appropriate material (base material). . As the additional shape, a thin film shape, a linear shape, a net shape, a strip shape, a comb shape, a granular shape, an island shape, or the like can be appropriately selected and used depending on a base material to be described later.

Since Ti and Zn can be used as a photocatalyst, for example, by oxidizing plate-like Ti, it can be suitably used depending on the type of apparatus.
As an example of immobilization of a photocatalyst, a photocatalyst is used as a base material, and a known conductive material such as SUS, Cu-Zn, Al, or ceramic, fluororesin, glass or glassy material is coated, or the photocatalyst is coated on a plate. , Granular, island-shaped, linear, net-like, membrane, or fibrous material may be coated, wrapped, or sandwiched and fixed. As an example, there is a coating of titanium dioxide on a glass plate by a sol-gel method. The photocatalyst can be used as it is in powder form, but can be used in an appropriate shape by a known method such as sintering, vapor deposition, sputtering or the like.

Further, in order to improve the photocatalytic action, a substance such as Pt, Ag, Pd, RuO ₂ , or Co ₃ O ₄ can be added to the photocatalyst. The addition of the substance is preferable because the photocatalytic action is promoted. These can be used alone or in combination. Usually, the addition amount is 0.01 to 10% by weight with respect to the photocatalyst, and an appropriate concentration can be selected by conducting a preliminary test depending on the kind of the added substance and the required performance.
As the addition method, known means such as an impregnation method, a photoreduction method, a sputter deposition method, and a kneading method can be appropriately used.
The photocatalyst may be installed on the cleaning device as long as it is a position and installation method where ultraviolet rays from an ultraviolet ray source are effectively irradiated. For example, there is (1) integration with the photoelectron emitting material (Japanese Patent Application No. Hei 8-132563). For example, a method of adding a photocatalyst and a substance that emits photoelectrons onto the base material, photoelectron There are a method for adding a photocatalyst onto a substance that emits light and a method for adding a substance that emits photoelectrons onto the photocatalyst.

As another example, there is (2) integration with the above-mentioned electrode material for electric field (Japanese Patent Application No. 8-231290). For example, a photocatalyst is added to a SUS material in a net or island shape (SUS is a positive electrode) A method in which a photocatalyst is added to a ceramic film and sandwiched between open mesh SUS materials (SUS is a positive electrode), (3) a photocatalyst is placed in a space in which air flows, and (4) on an ultraviolet lamp. There is a method of coating on the surface (Japanese Patent Application No. 8-31231), etc., and a preliminary test can be appropriately performed and determined according to the use destination, type of apparatus, condition (concentration) of processing air, required performance, and the like.
As already proposed by the present inventors, when the photoelectron method and the photocatalyst method are integrated, the particulate matter and the gaseous pollutant can be removed at the same time with a simple configuration. ((1) Proceedings of the 14th Air Cleaning and Contamination Control Research Conference, p. 201-204, 1996, (2) Proceedings of the 15th Air Cleaning and Contamination Control Research Conference, p. 314, 1997, (3) JP-A-1-266864, Japanese Patent Application No. 8-352382).

3) Method by ion exchange fiber The ion exchange fiber is effective for removing acidic gases such as SO ₂ and NOx, and alkaline gases such as NH ₃ and amines as gaseous pollutants. Therefore, depending on the application destination (required performance), it is effective to use in addition to the photoelectron method and / or the photocatalyst method.
Such an ion exchange fiber will be described. This is a natural fiber or synthetic fiber, or a cation exchanger or anion exchanger, or a cation exchange group and an anion exchange group on a support surface such as a mixture thereof. The ion exchanger is also supported, and as a method thereof, it may be directly supported by a fibrous support, or after being formed into a woven, knitted or flocked form, it may be supported by this. it can. In any case, it is sufficient that the fiber finally supports the ion exchanger.

As a method for producing an ion exchange fiber used in the present invention, an ion exchange fiber produced by using graft polymerization, particularly radiation graft polymerization, is suitable. This is because various materials and shapes can be used. As the natural fiber, wool, silk, and the like can be suitably used. As the synthetic fiber, a material made of a hydrocarbon polymer, a material made of a fluorine-containing polymer, or polyvinyl alcohol, polyamide, polyester, poly Acrylonitrile, cellulose, cellulose acetate and the like can be applied.
Examples of the hydrocarbon polymer include aliphatic polymers such as polyethylene, polypropylene, polybutylene, and polybutene, aromatic polymers such as polystyrene and poly α-methylstyrene, alicyclic polymers such as polyvinylcyclohexane, or the like. These copolymers are used. Examples of the fluorine-containing polymer include polytetrafluoroethylene, polyvinylidene fluoride, ethylene-tetrafluoroethylene copolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and vinylidene fluoride-6-fluoride. Propylene copolymer or the like is used.

In any case, the support has a large contact area with the gas stream, a shape with low resistance, can be easily grafted, has high mechanical strength, and is free from fiber scrapping, generation and heat. A small amount of material may be used, and the material can be appropriately selected in consideration of the intended use, economy, and effects. Usually, polyethylene is generally used, and polyethylene or a composite of polyethylene and polypropylene is particularly preferable.
Next, the cation exchanger is not particularly limited, and various cation exchangers or anion exchangers can be used. For example, taking the case of cation exchange as an example, a cation exchange group containing body such as carboxyl group, sulfonic acid group, phosphoric acid group, phenolic hydroxyl group, primary to tertiary amino group, quaternary ammonium group, etc. Or an ion exchanger having both the positive and negative ion exchange groups.

Specifically, for example, acrylic acid, methacrylic acid, vinyl benzene sulfonic acid, styrene, halomethyl styrene, acyloxy styrene, hydroxy styrene, amino styrene and other styrene compounds, vinyl pyridine, 2-methyl-5-vinyl on the fiber. A fibrous anion exchanger having a cation or anion exchange group by grafting pyridine, 2-methyl-5-vinylimidazole, acrylonitrile and then reacting with sulfuric acid, chlorosulfonic acid, sulfonic acid or the like as necessary. Is obtained.
These monomers may be graft-polymerized onto fibers in the presence of monomers having two or more double bonds such as divinylbenzene, trivinylbenzene, butadiene, ethylene glycol, divinyl ether, ethylene glycol dimethacrylate, and the like. Good. In this way, ion exchange fibers are produced. The diameter of the ion exchange fiber is 1-1000 μm, preferably 5-200 μm, and can be appropriately determined depending on the type of fiber, application, and the like.

Among these ion exchange fibers, the way to use the cation exchange group and the anion exchange group can be determined by the kind and concentration of the component to be removed in the target treatment gas. For example, the component to be removed may be measured and evaluated in advance, and the type and amount of ion exchange fiber corresponding to it may be used. When it is desired to remove the alkaline gas, it has a cation exchange group (cation exchanger). When it is desired to remove the acidic gas, it has an anion exchange group (anion exchanger). Fibers with both negative and negative exchange groups can be used.
As the ion exchange fiber, as proposed previously by the present inventors, it is preferable to use one produced by radiation graft polymerization because it is particularly effective, and can be used as appropriate (Japanese Patent Publication No. 5-9123, Japanese Patent Publication No. 5). -67325, Japanese Patent Publication No. 5-43422, Japanese Patent Publication No. 6-24626).

Ion exchange fibers are effective for collecting ionic substances (components), and the acidic gas and alkaline gas targeted by the present invention are considered to be ionic substances. Can be removed.
In particular, in the ion exchange filter (fiber) produced by radiation graft polymerization, the support is irradiated uniformly to the back, so that the ion exchanger (anion and / or cation exchanger) has a large area (high Since it is firmly (strongly) added to the density, the exchange capacity is increased, and the low-concentration ionic substance can be efficiently removed at high speed, which is practically effective. In addition, the production by radiation graft polymerization has advantages such as being able to have a shape close to that of a product, being able to be done at room temperature, being able to be done in the gas phase, being able to increase the graft rate, and being able to produce an adsorption filter with few impurities. For this reason, it has the following characteristics.

(a) Since ion exchange fibers (parts having an adsorption function) are uniformly added (high addition density) to the ion exchange fibers produced by graft polymerization by radiation irradiation, the adsorption speed is high and the adsorption amount is large.
(B) Less pressure loss.
The above-described photoelectron method, photocatalyst method, and ion exchange fiber method can be used alone or in combination of two or more, and cleaning can be performed at one place or at a plurality of places.
That is, a preliminary test can be appropriately performed and determined according to the application destination, the type of device, the shape, and the required performance.
For example, simultaneous removal of fine particles and gaseous pollutants (especially organic gas) is a photoelectron method and photocatalytic method, and simultaneous removal of fine particles and gaseous pollutants (especially NH ₃ , NOx) is a photoelectron method. The method using ion exchange fibers and the simultaneous removal of fine particles and gaseous pollutants (organic gas, NH ₃ , NOx) include a combination of a photoelectron method, a photocatalyst method, and an ion exchange fiber method.

Next, the heat insulating material that covers the cleaning device will be described.
As the heat insulating material that can be used in the present invention, any of well-known heat insulating materials and heat insulating materials can be used.
For example, as a heat insulating material, a mahobin principle using a double tube can be used, and as a heat insulating material, an organic heat insulating material such as foamed polystyrene and an inorganic heat insulating material such as glass wool can be used.
These heat insulating materials and heat insulating materials can be appropriately selected and used depending on the use mode of the apparatus, and in order to prevent generation of fine particles and harmful gases from the heat insulating materials and the heat insulating materials themselves, the heat insulating materials and the heat insulating materials are used. The material can be used by covering it with a material that does not generate these harmful substances.

Next, a description will be given of a wafer carrier storage portion when used in a carrier box with a cleaning function.
The storage portion for the wafer carrier only needs to have a space large enough to store a commonly used wafer carrier. By using a stay guide suitable for various wafer carriers, the structure can be accommodated in a carrier box with a cleaning function.
The wafer carrier is preferably installed on top of the cleaning function, and the wafer is preferably arranged in parallel with the flow of clean air, ie, from below to above.
Any material may be used for the stay guide for making the structure in which clean air can flow from the entire bottom surface of the wafer carrier, but it is preferable to use a material that does not generate dust or gas from the material.

Next, the outer peripheral part of the cleaning device of the carrier box with a cleaning function will be described. The outer peripheral portion is a flow path that guides the contaminants on the surface of the substrate, such as a wafer, to the bottom of the cleaning unit by the gas cleaned by the cleaning device or the contaminated gas mixed from the outside. The outer peripheral portion can be used in four directions (one round), but can have a structure appropriately selected according to the structure of the device, one surface, two surfaces, or three surfaces.
Next, an electric system that supplies electricity to the cleaning device will be described.
Depending on the operation (use conditions) of the carrier box with a cleaning function, it may be preferable that the power supply for supplying electricity to the cleaning device is configured so that the gas cleaning unit can always operate even during transportation. In such a case, the power supply system can have a structure that can be operated by two systems of a general commercial power supply and a battery power supply. A well-known battery can be used as appropriate. For example, an electricity storage location such as alkali, manganese, lithium, and the like can be appropriately selected depending on the purpose of use.

EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is not limited to the following Example at all.
Example 1
The air cleaning in the liquid crystal glass (substrate) storage (stocker) 1 in a liquid crystal factory of a class 1000 clean room will be described with reference to FIG.
In FIG. 1, the air in the substrate storage 1 that is a sealed space is cleaned by an ultraviolet lamp 2, a photoelectron emission material 3, a photoelectron emission electrode 4, and an electrode for collecting charged fine particles, which are installed below the floor 14. 13 is carried out by an air cleaning unit (A + B) which is a cleaning device of the present invention consisting of 13 (particulate charged part: A, collector part of charged particulate: B).
Particulate matter (fine particles) 6 enters the liquid crystal glass storage 1 from the clean room by opening and closing the storage 1 such as the substrate storage carrier 10 storing the liquid crystal glass substrate 11 in and out of the storage 1. The particulate matter 6 is charged and collected by the air cleaning unit (A + B) of the present invention, and the space C to be cleaned in which the substrate 11 is stored becomes an ultra-clean space that is cleaner than Class 1.

That is, when the photoelectron emitting material 3 is irradiated with ultraviolet rays from the ultraviolet lamp 2 in a state where an electric field is formed between the photoelectron emitting material 3 and the electrode 4, photoelectrons are emitted from the photoelectron emitting material 3. Here, the fine particles 6 in the liquid crystal glass storage 1 are charged by the aforementioned photoelectrons in the fine particle charging / collecting portion (A + B) composed of the ultraviolet lamp 2, the photoelectron emitting material 3, and the electrodes 4 and 13, and become charged fine particles. The charged fine particles are collected by the electrode 13 and are supercleaned more cleanly than the class 1 in the storage 1.
Reference numerals 9a to 9c denote air flows generated by the ultraviolet lamps, which are generated as the temperature rises due to ultraviolet irradiation inside the air cleaning unit (A + B). 9a is the purified air cleaned by the air cleaning unit (A + B). By this flow (9a to 9c), the fine particles 6 in the storage 1 are sequentially moved to the charging / collecting section (A + B) and charged / collected. Reference numeral 14 denotes a floor surface on which the substrate storage carrier 10 in which a glass substrate is stored is stored.

The installation of the air purifying unit (A + B) is not horizontal and has a slight inclination in order to make the air flows 9a to 9c due to the rising air flow from the unit effective.
When the liquid crystal glass substrate 11 is stored in the storage 1, contamination by the particulate matter 6 is prevented, so that the circuit (pattern) on the substrate is not disconnected or short-circuited, and the yield in product manufacturing is improved. To do.
The ultraviolet lamp 2 of this example is a sterilization lamp, the photoelectron emission material 3 is Cu-Zn plated with Au, and the photoelectron emission electrode material 4 and the charged particle collecting material 13 are SUS materials.
The air purifying unit (A + B) can be removed as appropriate during maintenance and inspection, and is one of the features of the present invention.

Example 2
The air cleaning in the wafer storage (stocker) 1 in the semiconductor factory of a class 1000 clean room will be described with reference to FIG.
In FIG. 2, the air cleaning in the wafer storage 1 which is a sealed space is performed by the ultraviolet lamp 2 ₋₁ , the photocatalyst 15, the ultraviolet lamp 2 ₋₂ , the photoelectron emitting material 3, and the photoelectron emitting apparatus installed below the floor 14. This is carried out by the air cleaning unit (A + B) of the present invention comprising the electrode 4 and the charged particulate collection material 13. As a gaseous harmful component in a clean room, organic gas is present as non-methane hydrocarbon, 1.3 ppm, and NH ₃ is present at 50 ppb.

In the wafer storage 1, the particulate matter (fine particles) 6 and the gaseous harmful components 16 (here) are opened from the clean room by opening and closing the storage 1 such as the wafer carrier 10 storing the wafer 11 in and out of the storage 1. Then, when adhering to the wafer, hydrocarbons (for example, phthalate ester) that increase the contact angle of the wafer surface or NH ₃ ) that causes poor resolution (cloudiness) intrude, but the particulate matter 6 is present in the present invention. is charged, trapped in the air cleaning unit (a + B), also gaseous harmful components 16 is in contact with the photocatalyst 15 which exhibits a photocatalytic activity by irradiation with ultraviolet light from the ultraviolet lamp 2 _-1, degradation, detoxification Then, the space to be cleaned in which the wafer 11 is housed is an ultra-clean space that is cleaner than Class 1 in which gaseous harmful components are rendered harmless (inert gas is formed with respect to the wafer 11).

That is, photoelectrons are emitted from the photoelectron emission material 3 when the photoelectron emission material 3 is irradiated with ultraviolet rays from the ultraviolet lamp _2-2 in a state where an electric field is formed between the photoelectron emission material 3 and the electrode 4. Here, the fine particles 6 in the wafer storage 1 are charged by the above-mentioned photoelectrons in the fine particle charging / collecting portion composed of the ultraviolet lamp _2-2 , the photoelectron emitting material 3, and the electrodes 4 and 13, and become charged fine particles. The charged fine particles are collected by the electrode 13 and are super-cleaned in the wafer storage 1.
On the other hand, the gaseous harmful component 16 comes into contact with the photocatalyst 15 and is rendered harmless by the air flows 9a to 9c.
Reference numerals 9a to 9c show the flow of air in the storage 1 caused by the temperature rise inside the air cleaning unit of the present invention by the ultraviolet lamps 2 _-1 and 2 _-2 , and this flow causes the particulates 6 and 6 in the storage 1 to Gaseous harmful components 16 are effectively moved sequentially to the unit (A + B) and processed. 9a is the purified air cleaned by the air cleaning unit (A + B).

By such treatment, an ultra-clean space that is 0.1 ppm or less as non-methane hydrocarbon and NH ₃ 1 ppb or less and cleaner than Class 1 is obtained.
The details of the treatment of the gaseous harmful component with the photocatalyst are not clear because the concentration of the gaseous harmful component is extremely low.
Hydrocarbons (non-methane hydrocarbons, HC) may cause contamination even at normal air concentrations (eg, general outside air) depending on the substrate.
Various H.P. Of C, the component that increases the contact angle is considered to differ depending on the type of substrate (wafer, glass, etc.) and the type and properties of the thin film on the substrate. As a result of intensive studies, the present inventors have found that it is effective to remove nonmethane hydrocarbon as an index by removing it to 0.2 ppm or less, preferably 0.1 ppm or less by a decomposition treatment with a photocatalyst.

That is, what can be said in common with the organic gas (HC) that increases the contact angle of the substrate surface in a normal clean room is the high molecular weight H.C. C is the main, and has a structure of —CO and —COO (having hydrophilicity) as its structure. This H. C can be considered as a hydrophobic substance having a hydrophilic part (—CO, —COO bond part) (the part of —C—C— of the basic structure of HC).
To explain in concrete example, the organic gases increase the contact angle of the surface of the substrate such as a wafer substrate in a normal clean room, high molecular weight of C ₁₆ -C ₂₀ H. C, for example, phthalic acid ester and higher fatty acid phenol derivative, and what is common to these components has -CO and -COO bonds (having hydrophilicity) as chemical structures. These polluted organic gases are caused by plasticizers, mold release agents, antioxidants, and the like of polymer products, where the polymer products are present (“Air Cleaner”, Vol. 33, Vol. 1, p16-21, 1995).

The details of the processing mechanism of these organic gases by the photocatalyst are unknown, but can be estimated as follows. That is, in these organic gases, -CO and -COO bonds are hydrogen bonded to OH groups on the wafer or glass surface, and the upper part becomes a hydrophobic surface. As a result, the wafer or glass surface becomes hydrophobic, and the contact angle When the film is formed on the surface, the adhesion of the film is weak.
When the photocatalyst is installed in an atmosphere in which an organic gas exists, first, the organic gas is adsorbed on the photocatalyst like the wafer or glass surface, and then the -CO and -COO bonding portions which are active portions thereof are Under the action of the photocatalyst (irradiation of light to the photocatalyst), it is converted into another stable form. As a result, the organic gas is in a stable form and does not adhere to the wafer or glass substrate, or does not exhibit hydrophobicity even when attached.

If the wafer 11 is stored in the storage 1, contamination by the particulate matter 6 and the gaseous harmful substance 16 is prevented, so that the circuit (pattern) on the wafer is not disconnected or short-circuited. Since the contact angle of the surface does not increase (the adhesion of the film formed on the wafer is strong) and no resolution failure occurs, the yield in product manufacturing is improved.
In this example, the ultraviolet lamps 2 _-1 and 2 _-2 are sterilizing lamps, the photoelectron emitting material 3 is Cu-Zn plated with Au, the electrode material 4 and the charged particle collecting material 13 are SUS materials, and the photocatalyst is TiO _2. It is.
The air purifying unit (A + B) can be removed as appropriate during maintenance and inspection, and is one of the features of the present invention.
2, the same reference numerals as those in FIG. 1 denote the same meaning.

Example 3
In FIG. 2 of Example 2, the air cleaning in the wafer storage 1 performed by combining the ion exchange fibers 17 is shown in FIG.
Class 1,000 clean rooms have 1.3 ppm organic gas as non-methane hydrocarbon, NH ₃ 580 ppb, and SOx 80 ppb as gaseous harmful components.
In FIG. 3, it works as shown in FIG. Here, ionic substances are first removed up to NH ₃ 10 ppb and SO x ₅ ppb or less by ion exchange fibers (anion type and cation type). Next, as shown in FIG. 2, the non-methane hydrocarbon is removed to 0.1 ppm or less and NH ₃ to 0.1 ppb or less by the action of the photocatalyst 15, and then the fine particles are removed by the photoelectrons generated from the photoelectron emitting material 3. A clean ultra-clean space is created.
3, the same reference numerals as those in FIGS. 1 and 2 indicate the same meaning.

Example 4
FIG. 4 shows another embodiment of the air cleaning unit (A + B) of the present invention using the photoelectrons and the photocatalyst shown in FIG. 2 of the wafer storage in Example 2.
This unit (A + B) is installed in the lower part of the floor 14 of the wafer storage 1 and has an ultraviolet lamp 2 in the center, Au3 as a photoelectron emitting material coated on the lamp, and photoelectron emission on its opposite surface. It comprises a wire mesh electric field electrode material 4, a charged particulate collection material 13, and a photocatalyst 15.
Reference numeral 18 denotes a guide plate that guides the updraft 9a, which is purified air, to the space C to be cleaned.
The basic action here is as shown in FIG. 2, but the features of this embodiment are as follows.
Since the ultraviolet lamp 2 is installed at the center, the updraft 9a can be effectively used by the lamp, which is a feature of this embodiment.
That is, since the air flow 9a to 9c in the storage 1 is effectively generated by installing the lamp 2 at the center of the lower part of the storage 1, the fine particles 6 and the gaseous harmful components 16 in the storage 1 are effective. Are sequentially sent to the air cleaning unit (A + B) by the airflows 9a to 9c and efficiently removed.

As a result of the above action, the clean space C is 0.1 ppm or less as non-methane hydrocarbon and NH ₃ 1 ppb or less, and an ultra-clean space that is cleaner than Class 1 is obtained.
If the wafer 11 is stored in the storage 1, contamination by the particulate matter 6 and the gaseous harmful substance 16 is prevented, so that the circuit (pattern) on the wafer is not disconnected or short-circuited. Since the contact angle of the surface does not increase (the adhesion of the film formed on the wafer is strong) and no resolution failure occurs, the yield in product manufacturing is improved. Here, the ultraviolet lamp 2 is a sterilizing lamp, the electrode material 4, the charged particulate collection material 13 is a SUS material, and the photocatalyst is TiO ₂ . The air cleaning unit (A + B) can be removed as appropriate for maintenance and inspection and is a feature of the present invention.
4, the same reference numerals as those in FIG. 2 indicate the same meaning.
In FIG. 4, a plurality of wafer carriers 10 are installed in the wafer storage 1, but the above-described air cleaning unit (A + B) can be installed in a wafer box in which one wafer carrier 10 is stored. It was.

Example 5
FIG. 5 shows another embodiment of the air purification unit (A + B) of the present invention in FIG.
This unit (A + B) is installed at the lower part of the floor 14 of the wafer storage 1, the ultraviolet lamp 2 at the center, and the wire mesh electrode material 4 for the photoelectron emission arranged circumferentially around it. The wire mesh photoelectron emitting material 3, the charged fine particle collecting material 13, and the photocatalyst 15 installed on the opposite side.
The feature of this embodiment is that the strength of the electric field (for photoelectron emission) may be weak by using the wire mesh photoelectron emission material 3, which is 10 V / cm here.
5, the same reference numerals as those in FIG. 4 indicate the same meanings, and the operations and effects thereof are the same as those in the fourth embodiment.

Example 6
The air cleaning in the pass box (delivery device such as instruments installed between the outside and the clean room) 1 in the class 10,000 biological clean room will be described with reference to FIG.
In FIG. 6, the air in the pass box 1, which is a sealed space, is cleaned by an ultraviolet lamp (sterilization lamp) 2 ₋₁ , a photoelectron emitting material 3, a photoelectron emitting electrode material 4, a charged particle trapping device installed at the lower part of the floor 14. It is carried out by the air cleaning unit (A + B) of the present invention comprising the collecting member 13.
Each time the utensil 19 carried into the clean room is introduced into the pass box 1, the particulate matter 6 containing fungi and microorganisms enters from outside, but the particulate matter containing the fungi and microorganisms enters. The substance 6 is charged and collected by the air cleaning unit (A + B) of the present invention. Here, since the fungi and microorganisms are collected in the charged particle collecting material 13 of the present invention, they are irradiated with an ultraviolet lamp (sterilization lamp) 2 _{-1 in} the immediate vicinity and completely sterilized (sterilized). This is a feature of this embodiment.

That is, airborne fungi and microorganisms 6 is first partially in the space C of the pass box is sterilized by sterilizing lamp 2 _-2, surviving fungi and microorganisms, UV resistance of fungi such as, the Since it is collected by the charged particle collection material 13 of the invention and irradiated with a sterilization line (254 nm ultraviolet light from a sterilization lamp), it is completely sterilized (sterilized). Thus, the to-be-cleaned space C in which the instruments 19 are placed becomes an ultra-clean space from which airborne fungi, microorganisms, and fine particles 6 are removed.
That is, when the photoelectron emitting material 3 is irradiated with ultraviolet rays from the ultraviolet lamp 2 in a state where an electric field is formed between the photoelectron emitting material 3 and the electrode 4, photoelectrons are emitted from the photoelectron emitting material 3. Here, the particulate matter 6 containing fungi and microorganisms in the pass box 1 is in the particulate matter charge collecting section A + B including the ultraviolet lamp 2, the photoelectron emitting material 3, the electrode 4, and the charged particle collecting material 13. Charged by the above-described photoelectrons to form a charged particulate matter, which is collected by the electrode 13 and sterilized and dust-removed in the pass box 1 to be ultra-cleaned.

Reference numerals 9a to 9c denote air flows in the pass box 1 that occur as the temperature inside the air purifying unit (A + B) of the present invention is increased by the ultraviolet lamp 2, and this flow includes fungi and microorganisms in the pass box 1. The particulate matter 6 effectively moves to the charge / collection part A + B and is charged / collected.
When the instrument (eg, surgical instrument) 19 is introduced into a clean room using the pass box 1, contamination of the instrument 19 from fungi and microorganisms is prevented.
The air cleaning unit (A + B) can be removed as appropriate for maintenance and inspection, and is one of the features of the present invention.

Example 7
The following sample air is put into the storage having the structure shown in FIG. 2, and the concentration in the space to be cleaned and the particles on the wafer are measured using the particle measuring device and the gas measuring device with or without the operation of the air cleaning unit of the present invention. The number and contact angle were examined.
1) Storage; 80 liters 2) Air purification unit; UV lamp, photoelectron emission material, electrode material, photocatalyst
2 is configured as shown in FIG. 2 and below the storage floor as shown in FIG.
Installation.
(1) UV lamp: sterilization lamp 10W,
(2) Photoelectron emitting material: Cu-Zn with Au plating,
(3) Electron emission electrode: 50 V / cm, electrode material SUS,
(4) Charged particulate collection material: 800 V / cm, electrode material SUS,
(5) Photocatalyst: Quartz glass coated with TiO ₂ by sol-gel method

3) Sample air; clean room air of a semiconductor factory (class 1,000).
H. C: 1.3 ppm,
NH ₃ : 65 ppb,
SOx: 10 ppb,
4) Wafer; 8 inches,
5) Measuring instrument; (1) Fine particle concentration in space: Light scattering particle counter
(> 0.1 μm),
(2) H. C concentration: GC method,
(3) Same NH ₃ concentration: Chemilmi method,
(4) Number of fine particles on wafer: Wafer / dust inspection device,
(5) Contact angle on wafer: Water drop type contact angle meter The class indicates the number of particles of 0.1 μm or more contained in 1 ft ³ .

Results (1) Table 1 shows the fine particle concentration in the space and the number of particles on the wafer.
Table 1 shows a comparison (blank) without UV irradiation, no photocatalyst (with photoelectron emitting material), and photocatalyst (without photoelectron emitting material).

(2) H. Table 2 shows the C concentration and NH ₃ concentration.
Table 2 shows the same comparison as Table 1.

(3) Table 3 shows the contact angle on the wafer.
Table 3 shows the same comparison as Table 1.

Example 8
In Example 7, ion exchange fibers were added as shown in FIG. 3, the sample was placed in a storage room in the following sample air environment, operated for a long period of time, and the performance was examined by measuring the contact angle of the wafer. The storage was opened and closed 10 times / day.
1) Ion exchange fiber (anion type, cation type)
The production method is shown below.
(A) Anion exchange fiber: Fibrous polypropylene was irradiated with an electron beam of 20 Mrad in nitrogen, then immersed in a solution containing 60% and 40% of a hydroxystyrene monomer and isoprene, respectively, and heated to a temperature of 35 ° C. for grafting. A polymerization reaction was performed. After the reaction, quaternary amination was performed to obtain an anion exchange fiber.
(B) Cation exchange fiber: Fibrous polypropylene was irradiated with an electron beam of 20 Mrad in nitrogen, then immersed in an aqueous solution containing 45% acrylic acid, and heated to a temperature of 35 ° C. to conduct a graft polymerization reaction. After the reaction, it was treated with a sodium hydroxide solution to obtain a cation exchange fiber.

2) Sample air; clean room air of a semiconductor factory (class 1000),
H. C: 1.4 ppm,
NH ₃ : 480 ppb,
SOx: 250 ppb,
NOx: 320ppb
Results The results are shown in FIG. In FIG. 7, -O- for the present invention,-●-for non-ultraviolet irradiation (blank) for comparison, and-△-for those not added with ion exchange fibers (only the operation of the photoelectron emitting material and the photocatalyst) Show.
In order to investigate the effect of removing the ionic substance by the ion exchange fiber, the sample air was passed through the ion exchange fiber at 100 ml / min, and the outlet concentration was examined as follows.
NH ₃ : 10 ppb or less (measurement: Chemilmi method)
SOx: 5 ppb or less (measurement: solution conductivity method)
NOx: 5 ppb or less (Measurement: Chemilmi method)

Example 9
Next, an example in which the sealed space with a cleaning function of the present invention is used in a carrier box with a cleaning function is shown, and FIG. 9 is an overall configuration diagram thereof.
In FIG. 9, 20 is a wafer carrier box body, 21 is a stay guide, 22 is a return flow path, 23 is a return contaminated air flow, 24 is clean air flow, 25 is contaminated air, and 27 is a power supply unit. The same symbols as in the previous figure have the same meaning. The photoelectron emitting material 3 is coated on the surface of the ultraviolet lamp 2.
Contaminants enter the carrier box 20 from the outside when the wafer carrier 10 is taken in and out. The invading contaminant enters the charging portion A through the outer peripheral path 22, and is charged by photoelectrons generated by the ultraviolet irradiation from the ultraviolet lamp 2 to the photoelectron emitting material 3 under an electric field.

Then, the gas containing charged fine particles heated by the ultraviolet lamp 2 rises to reach the collecting part B, and the charged fine particles are collected and removed by the electrode plates 13a and 13b of the collecting part and cleaned. The gas 24 rises over the entire surface from the gap between the electrode plates 13a and 13b, and cleans the wafer storage portion c where the wafer 11 is present.
The gas which cleaned the storage part c is circulated through the outer peripheral path 22 from the top part of the storage part.
In the storage section c, the wafer 11 is preferably held in the vertical direction along the gas flow. Thereby, it can flow without obstructing the flow of gas, and the cleaning of the storage section can be achieved quickly.
FIG. 10 shows an example in which the carrier box 20 is provided with an opening / closing door 26 for taking in and out the wafer carrier 10 on the ceiling (a) or the side (b).

Example 10
The following sample air was put into the carrier box having the configuration shown in FIG.
1) Storage unit; 30 liters 2) Air purification unit (1) Ultraviolet lamp: sterilization lamp 8W,
(2) Photoelectron emitting material: Au (Au is coated on a germicidal lamp)
(3) Electron emission electrode: 10 V / cm, electrode material: SUS,
(4) Charged particle collection unit: 5000 V / cm, electrode material: SUS,
3) Sample air; clean room (class 1000),
4) Wafer; 8 inches,
5) Measuring instrument; (1) Fine particle concentration in space: Light scattering type pertcle counter
(> 0.1 μm),
(2) Contact angle on wafer: Water drop type contact angle meter,
In the test of the contamination state of the wafer surface in the carrier box, all test wafers were cleaned in advance, and wafers having an initial contact angle value of 7 degrees or less were used.
The class indicates the number of particles of 0.1 μm or more contained in 1 ft ³ .

FIG. 11 shows the measurement results of the dust removal characteristics of the fine particles in the carrier box.
The vertical axis represents the abundance ratio of the fine particles with respect to the initial fine particle concentration, and the horizontal axis represents the operating time of the air cleaning device. In the figure, “a” shows the result when the present apparatus is operated, and “b” shows the measurement result when the air cleaning unit is stopped (power supply Off) as a comparison.
From the results shown in FIG. 11, it can be seen that when the cleaning device is not operated, the concentration of the fine particles is not attenuated and remains in the box. On the other hand, the fine particle concentration in the box was reduced from class 1000 to class 1 or less by operating the air purifier.
FIG. 12 shows the result of the contact angle of the wafer surface in the carrier box.
When exposed to clean room air (b in the figure), the contact angle increases with time and is contaminated. On the other hand, when the air purifier is activated (a in the figure), it is stable at 10 degrees or less. The contact angle does not increase.

2) By using ion exchange fibers in combination with 1) above,
(1) In addition to the above 1), ionic substances such as NH ₃ , amine, SOx and NOx can be removed simultaneously.
(2) That is, since multiple types (multi-components) can be removed simultaneously, the application destination (apparatus) of this cleaning method has been expanded, and practicality has been improved.
3) By using the carrier box with a cleaning function, the housed wafer and glass substrate can be held in an atmosphere of clean air so that they are not contaminated. Therefore, improvement in the yield of wafers and glass substrates can be expected.

The cross-sectional block diagram of the storage which installed the cleaning apparatus of this invention. The cross-sectional block diagram of the storage in which the other cleaning apparatus of this invention was installed. The cross-sectional block diagram of the storage in which the other cleaning apparatus of this invention was installed. The cross-sectional block diagram of the storage in which the other cleaning apparatus of this invention was installed. The cross-sectional block diagram of the storage in which the other cleaning apparatus of this invention was installed. The cross-sectional block diagram of the pass box which installed the cleaning apparatus of this invention. The graph which shows the change of the contact angle (degree) by driving | operation time (h). The cross-sectional block diagram of the wafer storage provided with the conventional cleaning apparatus. The whole block diagram which used the present invention for the carrier box with a cleaning function. It is the schematic which shows the attachment position of the opening / closing door of a carrier box, and shows a) a ceiling part and b) a side part. The graph which shows the particle | grain residual ratio (n / no) by elapsed time. The graph which shows the change of the contact angle (degree) by elapsed time.

Explanation of symbols

1: storage, 2: ultraviolet lamp, 3: photoelectron emitting material, 4: electrode, 5: photoelectron, 6: particulate matter, 9a to 9c: air flow, 10: carrier, 11: substrate, 13: electrode, 14: Floor, 15: Photocatalyst, 16: Gaseous harmful component, 17: Ion exchange fiber, 18: Guide plate, 19: Instruments, 20: Wafer carrier box body, 21: Stay guide, 22: Peripheral path, 23: Return polluted air flow 24: Clean air flow 25: Contaminated air 26: Opening / closing door 27: Power supply unit
A: Charging part, B: Collection part, C: Cleaning space part

Claims (10)

  In a method for sterilizing and cleaning a sealed space containing airborne bacteria and microorganisms by irradiating a photoelectron emitting material and / or photocatalyst with light from an ultraviolet light source, the floor surface of the sealed space or through a partition plate is used. A method for cleaning an enclosed space, characterized in that a photoelectron emitting material and / or a photocatalyst is sterilized and cleaned by irradiating light from an ultraviolet light source at a lower portion.   In a method for sterilizing and cleaning a sealed space containing airborne bacteria and microorganisms by irradiating a photoelectron emitting material and / or photocatalyst with light from an ultraviolet light source, the floor surface of the sealed space or through a partition plate is used. A method for cleaning an enclosed space, characterized in that a photoelectron emitting material and / or a photocatalyst is irradiated with light from an ultraviolet light source to be sterilized and cleaned, and the cleaned air is sent upward from the entire floor surface. The method for cleaning an enclosed space according to claim 1 or 2, wherein the cleaning is performed by further combining ion exchange fibers. 4. The method for cleaning an enclosed space according to claim 1, wherein the ultraviolet ray source is a sterilizing lamp.   In a sealed space containing airborne bacteria and microorganisms having a cleaning function using an ultraviolet light source and a photoelectron emitting material and / or a photocatalyst, the ultraviolet light source is placed on the floor surface of the sealed space or below the floor surface via a partition plate. A sealed space with a sterilizing and cleaning function, characterized in that a sterilizing and cleaning device in which a photoelectron emitting material and / or a photocatalyst is arranged is installed.   In a sealed space containing airborne bacteria and microorganisms having a cleaning function using an ultraviolet light source and a photoelectron emitting material and / or a photocatalyst, the ultraviolet light source is placed on the floor surface of the sealed space or below the floor surface via a partition plate. A sealed space with a sterilizing and cleaning function, in which a photoelectron emitting material and / or a photocatalyst are arranged around the center, and a sterilizing and cleaning device having an upward opening on the entire floor surface is installed.   The sealed space with a sterilizing and cleaning function according to claim 5 or 6, wherein the cleaning device further combines cleaning with ion exchange fibers.   8. The sealed space with a sterilizing and purifying function according to claim 5, wherein the cleaning device has an outer periphery covered with a heat insulating material and is insulated from the outside and the outer peripheral path.   The sealed space with a sterilizing and purifying function according to any one of claims 5 to 8, wherein the ultraviolet ray source is a sterilizing lamp.   The sealed space with a sterilizing and purifying function according to any one of claims 5 to 9, wherein the sealed space with a sterilizing and purifying function is a pass box, having a storage portion at an upper portion and a sterilizing and cleaning device at a lower portion. box.

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