KR20040024738A - Air filter for clean-room - Google Patents

Abstract

PURPOSE: An air filter for clean room is provided which prevents generation of contaminants due to corrosion by using a material with high acid resistance as a material for components of the air filter and reduces process cost by reducing replacement cost of the air filter. CONSTITUTION: The air filter for clean room comprising a frame(200); mediums(220) laid up perpendicularly to the air flowing direction so that one surface of the medium is oppositely directed to air flowing direction(250) inside the frame; and separators(230) which support the mediums, and which are positioned between the mediums and formed of a polymer based material having acid resistance for forming an air passageway, wherein the separators are formed of any one material selected from the group consisting of polystyrene, polyethylene, polypropylene, polyvinyl chloride, ethylene vinylacetate, polyethylene terephthalate, polycarbonate, polybutylene terephthalate, polyacetal and polyamide, wherein an oxide film is formed on an outer part of the frame to prevent corrosion of the frame, and wherein the mediums are fixed to the inner wall of the frame by sealant(210) such as polyurethane.

Description

Clean Air Filter {AIR FILTER FOR CLEAN-ROOM}

The present invention relates to an air filter for a clean room, and more particularly, to an air filter for a clean room having strong acid resistance.

In the manufacturing process of the semiconductor device, the yield of the semiconductor device is sensitive to the environmental conditions of the working space. Microparticles present in air also act as environmental conditions, and when the microparticles are present on a semiconductor substrate, short defects occur or unexpected problems occur during material application.

Therefore, semiconductor devices are manufactured in clean areas in which a specific environment called a clean room is created. The clean room controls pressure, temperature, and humidity, and maintains a class according to the number of particles present therein.

In order to maintain this rating, a thorough management of the particles is required, from the air coming in from the outside to the air circulating in the clean room. In order to maintain a high clean clean room, the external tank is used to first remove contaminants from the outside and to control basic humidity. In addition, a clean filter is installed inside the clean room to remove contaminants contained in the circulated air.

In general, ultra low penetration air (ULPA) filters and high efficiency particulate air (HEPA) filters are used in clean rooms to collect fine particles. The filter is composed of a filter for filtering contaminants and a separator for maintaining a gap between the filters. Glass fiber (glass-fiber) is mainly used as the material for the media, and the material of the separator is a paper material for the ULPA filter, and a metal material such as aluminum for the HEPA filter.

However, since the semiconductor manufacturing process uses strong acid chemicals, the aluminum film, which is weak in acid resistance, is corroded by chemical fumes existing in the air when used for a long time. Therefore, the filter generates contaminated particles due to corrosion of the separator even though the original installation purpose is to remove contaminated particles, and the filter does not remove the contaminated particles from the outside and is introduced into the clean room.

FIG. 1A is a scanning electron microscope (SEM) photograph of particles generated in a eroded filter, and FIG. 1B is a graph of the components of the particles of FIG. 1A.

Referring to FIGS. 1A to 1B, as a result of analyzing the components of the particles remaining in the clean room, it was found that aluminum 120 was the main component. Therefore, it can be seen that the fine particles are generated from the separator.

1C is a plan view of a semiconductor device in which a bridge is formed due to particles generated by a corrosion filter on a substrate on which a conductive pattern is formed.

Referring to FIG. 1C, while transferring the substrate on which the conductive pattern is formed, the metallic particles are adsorbed onto the semiconductor substrate to generate the bridge 130, thereby causing a shortness defect. Therefore, the contaminated particles reduce the production yield of the semiconductor device manufacturing process.

In order to prevent such a problem, the surface of the aluminum material used as the separator is coated with an epoxy to delay the corrosion. However, as time passes, the same problem occurs.

Since the life of the filter required to corrode the filter is short, the replacement cycle of the filter is shortened, thereby increasing the management cost, thereby increasing the process cost.

It is therefore an object of the present invention to provide an air filter for a clean room that can be used for a long time.

1A is a scanning electron microscope (SEM) photograph of particles generated in a eroded filter.

FIG. 1B is a graph of the components of the particles of FIG. 1A.

1C is a plan view of a semiconductor device in which a bridge is formed due to particles generated by a corrosion filter on a substrate on which a conductive pattern is formed.

2 is a perspective view of an air filter in a clean room according to an embodiment of the present invention.

3 is an electron micrograph of the surface before and after evaluation of three separators evaluated for resistance under the same conditions.

In order to achieve the above object, the present invention provides a frame, a media stacked vertically with respect to the air flow direction so as to face one surface and an air flow direction in the frame, and the media, and which are present between the media to provide an air passage. It is made of a separator having acid resistance to form a.

In this way, by using an acid resistant material for the material of the component of the air filter, it can be used for a long time to prevent the generation of pollutants due to corrosion.

Hereinafter, the present invention will be described in detail.

An air filter for a clean room supports a frame, a filter material stacked vertically with respect to the air flow direction so that one surface and an air flow direction thereof face in the frame, and the filter medium, and are acid resistant to exist between the filter materials to form an air passage. It is composed of a separator having a poly and series material.

In this case, the separator is made of any one material selected from the group consisting of polystyrene, polyethylene, polypropylene, polyvinyl chloride, ethylene vinyl acetate, polyethylene terephthalate, polycarbonate, polybutylene terephthalate, polyacetal and polyamide. .

In addition, the frame is formed with an oxide film on the outside to prevent corrosion.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

2 is a perspective view of an air filter in a clean room according to an embodiment of the present invention.

Referring to FIG. 2, the air filter includes a frame 200 forming an outline, a mediator 220 stacked in the exterior, and a separator 230 supporting the mediator 220 between the mediator 220.

An oxide film is formed on a surface of the filter frame 200 forming the outer portion of the air filter. Since the oxide film is highly acid resistant, it is not corroded by chemicals remaining in the air. The filter media 220 is vertically stacked with respect to the air flow direction 250 and is fixed to an inner wall of the frame 200 by a sealant 210 such as polyurethane. The filter material 220 is formed of a glass fiber or a polymer-based material and is laminated so that one surface thereof faces the air flow direction to adsorb fine particles.

Between the stacked media 220, a separator 230 may be positioned to support corrosion of the media 220. The separator 230 is formed of a polymer-based acid resistant material. The separator is formed between the media in a pleated form to act as a passage for air to pass between the pleats.

The polymer is polystyrene (PS), polyethylene (Polyehylene; PE), polypropylene (PP), polyvinyl chloride (PVC), ethylene vinyl acetate (Ethylene Vinylacetate (EVA), polyethylene terephthalate (Polyethylene) Terephthalate (PET), Polycarbonate (PC), Polybutylene Terephthalate (PBT), Polyacetal (PA), Polyamide (PC) and the like.

The polymers are readily available materials because they are inexpensive, easy to process, and mechanically superior.

The air filter composed of the frame 200, the filter medium 220, and the separator 230 is installed at the ceiling and the wall of the clean room and connected to the air duct for introducing fresh air into the clean room. Therefore, the air is purified by adsorbing the fine particles present in the air flowing into the clean room. At this time, the air passes through the duct through the duct, passes through the separator, or after passing through the separator, passes through the media.

In general, semiconductor processes use nitric acid (NO _x ) and sulfuric acid (SO _x ) -based acidic chemicals as etching solutions. The nitric acid gas and the chlorine gas hardly affect the corrosion in the pure gas state, but at low temperature, when the moisture in the air is condensed and becomes a liquid state, the nitric acid gas and the chlorine gas are locally strong to promote corrosion.

Therefore, when corrosion occurs in the separator of the air filter exposed to the inside of the clean room, fine particles formed as a corrosion is scattered inside the clean room. That is, in some areas of the stacked media, the air has already passed through the media in the duct rather than the separator, so that the air has passed through the media, so that the fine particles cannot be adsorbed and air is introduced into the clean room.

3 is an electron micrograph of the surface before and after evaluation of three separators evaluated for resistance under the same conditions.

Referring to FIG. 3, three separators each consisting of polyethylene terephthalate (PET), which is one of aluminum, epoxy coated aluminum, and an acid resistant polymer, were treated with the same concentration of hydrochloric acid under the same conditions.

After a certain period of time, the separators made of aluminum and epoxy-coated aluminum had only a slight difference, but the surfaces were all corroded, whereas the separators made of polyethylene terephthalate (PET) remained intact and remained in an initial state.

The results show strong acid resistance to the polymer. Therefore, the same applies not only to the hydrochloric acid solution containing chlorine, but also to acidic substances such as nitric acid and sulfuric acid.

As described above, according to the present invention, the separator of the air filter used in the semiconductor processing equipment is manufactured using a polymer material which is strong in acid resistance and chemically stable so as not to be corroded by the vapor of the chemical.

In this way, by using an acid resistant material as the material of the components of the air filter, it is possible to prevent the generation of pollutants due to corrosion.

In addition, since it does not corrode, it can be used semi-permanently. Therefore, it is possible to reduce the process cost due to the replacement of the air filter to obtain a process cost reduction effect.

As described above, although described with reference to a preferred embodiment of the present invention, those skilled in the art will be variously modified without departing from the spirit and scope of the invention described in the claims below. And can be changed.

Claims (3)

frame; A filter medium stacked vertically with respect to the air flow direction such that one surface thereof faces the air flow direction in the frame; And And a separator made of a polymer-based material having acid resistance to support the filter medium and to form an air passage between the filter medium. The method of claim 1, wherein the separator is any one selected from the group consisting of polystyrene, polyethylene, polypropylene, polyvinyl chloride, ethylene vinyl acetate, polyethylene terephthalate, polycarbonate, polybutylene terephthalate, polyacetal, polyamide, and the like. Clean room air filter, characterized in that made of the material. According to claim 1, wherein the frame is an air filter for a clean room, characterized in that the oxide film is formed on the outside to prevent corrosion.