JPH1170313A - Air cleaning filter, its production and advanced cleaning device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an air cleaning filter by which the surface of a substrate or the like is prevented from being contaminated by gaseous impurities by simultaneously removing not only trace gaseous inorganic impurities contained in air subject to treatment but also gaseous organic impurities. SOLUTION: The air cleaning filter 1 is produced by using powder of inorganic matter as a binder and sticking powder of fraipontite mineral on the surfaces of supporting bodies 12 and forming an inorganic matter layer. In the filter 1, outside frames 15a, 15b, 15c, 15d made of aluminum are assembled so as to be opened in the flowing direction of air to be treated (in the direction shown by open arrows 13 in a figure). Both corrugated sheets 10 in which powdery fraipontite is stuck on the surfaces by using the inorganic binder and thin plate sheets 11 are alternately laminated nearly parallel to the flowing direction 13 of air in the internal space of the outside frames 15a, 15b, 15c, 15d. In the inside of the inorganic matter layer, gaps becoming vent holes are formed in the parts in which fine particles of both powder of fraipontite mineral and powder of the binder consisting of inorganic matter adjoin. Gas subject to treatment enters the inside of the layer of inorganic matter so as to slip through the vent holes and reversely goes out from the inside of the layer of inorganic matter to the outside.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air purification filter for removing gaseous inorganic impurities and gaseous organic impurities in an atmosphere, which is used in advanced cleaning equipment such as a clean room, a clean bench or a storage. Further, the present invention relates to a method for manufacturing such an air purification filter and an advanced cleaning device using the air purification filter.

[0002]

2. Description of the Related Art Today, advanced cleaning equipment is widely used for manufacturing semiconductors and LCD panels. For example, a semiconductor manufacturing line from a bare wafer to the manufacture of 1MDRAM chips includes about 200 steps, and an LCD panel manufacturing line from elementary glass to a 9.4-type TFT includes about 80 steps. I have. In these production lines, it is difficult to always continuously flow a wafer or a glass substrate through each process. For example, TFT-LCD
In a production line, a semi-finished substrate on which a single circuit has been formed in a previous process takes several hours to several tens of hours in a transport container (carrier) or a storage (stocker) before being transferred to a subsequent process.
Inside, it stands by while exposing to the atmosphere of the advanced cleaning equipment.

As described above, when a semiconductor substrate or an LCD substrate is left for a long time in a normal high-purity cleaning device atmosphere, gaseous impurities derived from the high-purity cleaning device atmosphere adhere to their surfaces. In recent years, silicon wafers and LCDs that exist in gaseous form in such advanced cleaning equipment and are used in semiconductor manufacturing
An acidic substance, a basic substance, an organic substance, a dopant, and the like, which adhere to the surface of a glass substrate used for panel production and affect the characteristics of a semiconductor or an LCD panel, are included.

An example of actual measurement of the concentration of chemical contamination contained in an ordinary clean room atmosphere in which no countermeasures against chemical contamination for gaseous impurities has been taken is as follows.
000 ppt, basic substance is 1,000 ppt-10,
000 ppt, organic matter is 1,000 ppt to 10,000
0 ppt and the dopant is about 10 to 100 ppt. US SEMATECH May 31, 1995
Technology Transfer announced today
# 95052812A-TR "Forecast o
f Airborne Molecular Cont
amination Limits for the
0.25 Micron High Performa
According to the permissible concentration of chemical contamination (ppt) required for the 0.25 μm process ('98 or later) described in “Nice Logic Process”, the following control is required. That is, for an acidic substance, 180
Strict control of 5 ppt is required in the ppt and wiring process. For a basic substance, strict control of 1 ppb is required in a photolithography process. For the dopant, 0.1 pp in the gate oxide film pre-process was used.
An extremely strict control of t is required. Especially boron B
Is a cause of contaminating the channel region of the TFT transistor and deteriorating the transistor characteristics. For organic substances, 1 ppb in the gate oxide film pre-process and 2 ppb in the wiring process
Strict control of ppb is required.

[0005] Various advanced cleaning apparatuses for manufacturing semiconductor substrates and glass substrates, for example, various scale advanced cleaning apparatuses such as clean rooms, clean benches, clean chambers, various stockers for storing clean products, and mini-environments. In a local advanced cleaning apparatus called “Technology T” of SEMATECH,
According to transfer # 95050512A-TR, various gaseous impurities such as acidic substances, basic substances, organic substances, and dopants are problematic in controlling gaseous pollutants in these advanced cleaning apparatuses. this house,
The dopant exhibits a chemical behavior similar to an acidic substance as a water-soluble boric acid compound or phosphoric acid compound, and a filter capable of adsorbing and removing a gaseous acidic substance can also adsorb and remove the dopant. Batch removal of organic substances and dopants is required in the gate oxide film pre-process, and batch removal of acids and organic substances is required in the wiring step.

Of these four types of chemical contaminants, three of the acidic, basic, and dopant are water-soluble, and are prone to ion exchange reactions and neutralization reactions. Therefore, as means for removing these three types of chemical contaminants from the air in a clean space, there are means for dissolving and removing them in an aqueous solution by wet cleaning (scrubber) and chemical filters using so-called chemical filters such as ion-exchange fibers and chemically impregnated activated carbon. There was an adsorption means. On the other hand, among the four types of chemical pollutants, many organic substances are hardly soluble in water.
As means for removing air from the clean space, there has been physical adsorption means using activated carbon.

Here, gaseous inorganic impurities such as acidic substances, basic substances, and dopants have been conventionally removed by three methods: wet cleaning, ion exchange fiber, and chemically impregnated activated carbon.

[0008] In the wet cleaning, an acidic substance,
Dissolve and remove basic substances and dopants. The simplest form of a chemical filter using chemical-impregnated activated carbon is
2. Description of the Related Art A filling cylinder having a configuration in which a predetermined case or the like is packed with granular carbon impregnated with a chemical is known. Other types of chemical filters include a fibrous activated carbon impregnated with a chemical compound and an organic binder made of low-melting polyester or polyester non-woven fabric. Also known are block-shaped and sheet-shaped chemical filters which are firmly adhered to an adhesive. Chemical filters that use ion-exchange fibers can convert various ions that are acidic and basic impurities contained in the air into non-woven fabrics, papermaking, felt, etc. based on acidic cation-exchange fibers and basic anion-exchange fibers. The ion exchange and removal are performed by a filter consisting of

[0009]

In the wet cleaning, the initial cost of the spraying device is large, and the running cost due to the high pressure loss of the spray cannot be ignored. Furthermore, the advanced cleaning equipment used in the manufacture of semiconductor devices (LSI) and liquid crystal displays (LCD) is maintained at a temperature of 23 to 25 ° C. and a relative humidity of 40 to 55%. When circulating while performing wet cleaning, it is necessary to perform temperature and humidity control again on the air after droplet spraying in order to cope with a temperature drop and humidity rise after droplet spraying. In addition, it is necessary to remove the liquid droplets remaining in the air after the liquid droplets are sprayed later in the spraying device (so-called carryover problem). further,
There is a problem specific to water treatment, such as treatment of a washing liquid circulated in a spray device, for example, prevention of generation of bacteria and concentration and separation of dissolved contaminants.

[0010] The so-called chemical filter using chemical-impregnated activated carbon or ion exchange fiber has the following problems. First, as a problem common to both, for example, in the case of a clean room in which the ceiling surface is a clean air blowing surface, a chemical filter is arranged upstream of the particle removal filter mounted on the ceiling. This is an extremely effective means for removing gaseous impurities in the air atmosphere of a clean room. However,
Activated carbon is a flammable substance specified by the Fire Service Law, and ion-exchange fiber is also a material that is very easy to ignite. Therefore, from the viewpoint of disaster prevention, it is difficult to dispose a chemical filter using activated carbon or ion-exchange fiber on the ceiling.

A chemical filter using activated carbon impregnated with a chemical has the following problems. That is, the conventional chemical filter of the filling cylinder type has a drawback that although the adsorption efficiency of impurities is high, the pressure loss (ventilation resistance) is high. In addition, conventional chemical filters in the form of felt or sheet have excellent air permeability, and the adsorption efficiency is not so inferior to that of the filled cylinder. Adhesives (eg, neoprene resin, urethane resin, epoxy resin, silicone resin, etc.) and sealing materials (eg, neoprene rubber, silicone rubber, etc.) used to fix the filter medium to the surrounding frame The gaseous organic impurities generated from the gas are contained in the air after passing through the chemical filter, which may adversely affect the manufacture of semiconductors. In other words, the chemical filter using the felt-shaped or sheet-shaped chemical-impregnated activated carbon is capable of removing chemical or acidic impurities such as ppb-order trace impurities and / or ppt-order dopants contained in a clean room atmosphere. The gaseous organic impurities generated from the filter itself are mixed into the passing air.

Japanese Patent Application Laid-Open No. 61-10 / 1986 discloses this type of filter.
No. 3518. A filter made by impregnating a base material made of urethane foam with an aqueous solution containing powdered activated carbon, an emulsion adhesive, and a solid acid, and then drying the filter. Gaseous organic substances are released from the organic adhesive and from the urethane foam itself.

A so-called chemical filter using ion exchange fibers has the following problems. That is, binders and adhesives used for processing nonwoven fabrics, papermaking, felt, etc., based on ion-exchange fibers into filter media having excellent air permeability, and used for fixing the filter media to the surrounding frame. Gaseous organic impurities generated from a sealing material or the like are included in the air after passing through the chemical filter, which may adversely affect semiconductor manufacturing. There is also dust from the filter media.

Japanese Patent Application Laid-Open No. 6-633 describes this type of filter.
33 and JP-A-6-142439. In the former chemical filter using ion exchange fiber used in the air purification system, gaseous organic substances are desorbed from various additives contained in the polymer fiber of the constituent material, and some of the ion exchange groups are removed. May be eliminated as a carboxylic acid or ammonia. In the latter case, the so-called chemical filter using ion exchange fibers used in the method for purifying trace amounts of contaminated air in a clean room, the desorption of gaseous organic substances from various additives contained in the nonwoven fabric of the polymer fiber as a constituent material. And some of the ion-exchange groups may be eliminated as sulfonic acid, carboxylic acid, phosphoric acid, ammonia or amine.

[0015] A filter for removing particulate impurities must be provided on the downstream side for dust generation from the chemical filter medium. When a filter for removing particulate impurities (particle removal filter) is provided downstream of the chemical filter, the filter for removing particulate impurities is a component that contains a material that generates gaseous organic impurities. There is also a problem that the gas itself generates gaseous organic impurities.

Further, as a problem common to conventional chemical filters using chemical-impregnated activated carbon or ion-exchange fiber as an adsorption layer for removing inorganic impurities, when air containing both acidic and basic inorganic impurities is treated, Separately prepare an adsorbent material for removing acidic impurities and an adsorbent material for removing basic impurities, and use a mixture of these two adsorbent materials in a single adsorbent layer, or use them separately. There has been the complication that the adsorption layer for removing acidic impurities and the adsorption layer for removing basic impurities are manufactured and used in an overlapping manner.

In addition, when the clean room atmospheres of a plurality of processes are mixed without being separated, for example, when a plurality of processes are present in one large room clean room, the following inconvenience has occurred. By removing gaseous impurities such as acids, bases, and dopants in a process sensitive to inorganic impurities using a conventional chemical filter, the quality of the substrate was improved. In the process, gaseous organic impurities generated by the chemical filter itself did not affect the quality of the substrate. However, the same gaseous organic impurities caused surface contamination of the substrate in another process sensitive to the organic impurities in the same room, resulting in a deterioration in quality. Therefore, in a large clean room where multiple processes coexist, a chemical filter that removes gaseous inorganic impurities such as acids, bases and dopants not only has excellent performance in removing these gaseous inorganic impurities, The filter itself must not generate gaseous organic impurities. There has been a strong demand for the development of a chemical filter which can remove not only gaseous inorganic impurities such as acids, bases and dopants but also gaseous organic impurities which cause substrate surface contamination in a clean room atmosphere.

If one kind of adsorbing material capable of removing both acidic and basic inorganic impurities at once can be used for the adsorbing layer for removing the inorganic impurities, the adsorbing layer volume can be reduced, the pressure loss can be reduced, and the adsorbing layer manufacturing cost can be reduced. Advantages such as reduction of the amount can be expected. In the case of treating air containing both inorganic impurities and organic impurities, conventionally, a chemical filter for removing organic impurities using activated carbon has been required separately from a chemical filter for removing inorganic impurities. If we could invent a chemical filter that can remove both inorganic and organic impurities,
Advantages such as reduced filter volume, reduced pressure loss, and reduced filter manufacturing costs can be expected.

The following points should be noted when applying the chemical filter to an advanced cleaning device such as a clean room or a clean bench capable of preventing acid / basic contamination and organic contamination. (1) The chemical filter itself should not be a source of contamination of gaseous impurities or particulate impurities (so-called secondary contamination source). (2) The pressure loss of the chemical filter is low. (3) High removal performance of gaseous impurities and long life. As described above, the conventional chemical filter cannot be said to satisfy these points.

Therefore, an object of the present invention is to provide a filter which is excellent in disaster prevention, does not desorb gaseous organic impurities and gaseous inorganic impurities from the filter itself, and has only a small amount of gaseous inorganic impurities contained in the air to be treated. It is another object of the present invention to provide an air purification filter capable of simultaneously removing gaseous organic impurities and preventing surface contamination of a substrate or the like due to the gaseous impurities, and an advanced cleaning device using the air purification filter.

[0021]

Means for Solving the Problems In order to solve the above-mentioned problems, the invention of claim 1 relates to a method of fixing a powder of a frypontite mineral to a surface of a support using a powder of an inorganic substance as a binder. An air purification filter having a layer formed thereon. In the inorganic material layer, a gap serving as an air hole is formed at a position where the fine particles of the fly pontitite mineral powder or the inorganic binder powder are adjacent, and the gas to be treated passes through the air hole from the surface of the inorganic material layer. As described above, the material enters the inside of the inorganic material layer or conversely goes out from the inside of the inorganic material layer. Then, when passing through the inorganic material layer, acidic and basic gaseous impurities in the air are adsorbed and removed by the frypontite mineral.

According to a second aspect of the present invention, a powder of the frypontite mineral is prepared by adding talc, kaolin mineral, bentonite, diatomaceous earth, silica, alumina, a mixture of silica and alumina, aluminum silicate, activated alumina, porous glass,
An air purification method characterized in that an inorganic material layer is formed by fixing a powder of an inorganic substance comprising at least one of a hydrated magnesium silicate clay mineral having a ribbon-like structure, activated clay and activated bentonite to a surface of a support as a binder. Filter. For example, silica gel is used as silica. As the alumina, for example, alumina gel is used. As a mixture of silica and alumina, for example, a mixed gel of silica gel and alumina gel is used. Similarly, in the air purification filter according to the second aspect, when passing through the inorganic material layer, acidic or basic gaseous impurities in the air are adsorbed and removed by the flypontite mineral.

According to a third aspect of the present invention, there is provided the first aspect in which the powder of the frypontite mineral is fixed using the inorganic powder as a binder.
Inorganic material layer and at least one of diatomaceous earth, silica, alumina, mixture of silica and alumina, aluminum silicate, activated alumina, porous glass, hydrous magnesium silicate clay mineral with ribbon-like structure, activated clay, activated bentonite An air purification filter characterized in that a second inorganic material layer comprising: is there. For example, silica gel is used as silica. As the alumina, for example, alumina gel is used. As a mixture of silica and alumina, for example, a mixed gel of silica gel and alumina gel is used. In the air purifying filter according to the third aspect, even if the inorganic powder used as a binder in one of the first inorganic material layer and the second inorganic material layer is the same as the inorganic powder used in the other, it is different. You may. For example, the inorganic powder as a binder used in the first inorganic material layer may be a clay mineral such as talc, kaolin mineral, and bentonite. In addition, there is a gap serving as a vent hole at a position where the fine particles of the powder of the inorganic binder constituting the second inorganic material layer are adjacent to each other.
Similarly, in the air purification filter described above, acidic and basic gaseous impurities in the air are adsorbed and removed by the flypontite mineral. In addition, according to the air purifying filter of the third aspect, it has an affinity (adsorption rate) with the gaseous boron compound.
Since the inorganic material such as silica having a high content exists in both the first inorganic material layer and the second inorganic material layer, the total amount of the inorganic material such as silica increases as compared with the air purifying filter according to claim 1 or 2. It is characterized in that the removal efficiency of the gaseous boron compound is small with time and the gaseous boron compound can be removed for a relatively long time.

According to a fourth aspect of the present invention, the powder of the frypontite mineral is prepared by adding talc, kaolin mineral, bentonite, diatomaceous earth, silica, alumina, a mixture of silica and alumina, aluminum silicate, activated alumina, porous glass,
Air purification characterized in that pellets obtained by granulating a powder of an inorganic substance comprising at least one of a hydrated magnesium silicate clay mineral having a ribbon-like structure, activated clay and activated bentonite as a binder are fixed to the surface of a support. Filter. For example, silica gel is used as silica. As the alumina, for example, alumina gel is used. As a mixture of silica and alumina, for example, a mixed gel of silica gel and alumina gel is used. Similarly, in the air purifying filter according to the fourth aspect, a gap serving as a vent hole is formed at a position where the fine particles of the powder of the frypontite mineral or the powder of the inorganic binder are adjacent to each other, and the gas to be treated is discharged from the surface of the pellet. , So as to enter the inside of the pellet so as to pass through the vent hole, or to go outside from the inside of the pellet. Then, acidic or basic gaseous impurities in the air are adsorbed and removed by the frypontite mineral.

A fifth aspect of the present invention is to provide a diatomaceous earth, silica, alumina, a mixture of silica and alumina, around a first pellet obtained by granulating a powder of flypontite mineral using an inorganic powder as a binder. A second pellet coated with an inorganic powder comprising at least one of aluminum silicate, activated alumina, porous glass, hydrated magnesium silicate clay mineral having a ribbon-like structure, activated clay and activated bentonite is fixed to the surface of the support. It is an air purification filter characterized by having made it. For example, silica gel is used as silica. As the alumina, for example, alumina gel is used. As a mixture of silica and alumina, for example, a mixed gel of silica gel and alumina gel is used. In the air purifying filter according to the fifth aspect, there is a gap serving as a vent at a position where the inorganic powder coated around the first pellet is adjacent to each other. Then, from the surface of the pellet, the processing air enters the inside of the pellet so as to pass through the vent hole,
Conversely, they may go from inside the pellet to outside. Similarly, acidic and basic gaseous impurities in the air are adsorbed and removed by the frypontite mineral.

In the air purifying filter according to the second and fourth aspects, acidic or basic gaseous impurities in the air can be adsorbed and removed by the frypontite mineral. Since gaseous organic substances such as DOP, DBP, BHT, and siloxane can be adsorbed and removed by appropriately selecting the type having pores in the mesopore region, an atmosphere containing various types of chemical contaminants related to substrate surface contamination can be used. Can capture most of these chemical contaminants.

In addition to the above-mentioned effects of the air purifying filters of the second and fourth aspects, in the case where the first inorganic material layer is provided inside the air purifying filter of the third aspect and the air purifying filter of the fifth aspect, In addition, the outer inorganic material layer has an effect of preventing dust generation from the inorganic material layer composed of the binder of the powder of the frypontite mineral and the inorganic powder located below them. Further, in the air purifying filters according to the third and fifth aspects, the inorganic powder constituting the second inorganic material layer or the outer inorganic material layer is formed of a material such as DOP, DBP, BHT, siloxane or the like which contributes to the surface contamination of the substrate. If there are pores suitable for physical adsorption of gaseous organic substances, there is also an effect that these gaseous organic substances are adsorbed and removed by the pores. In the air purifying filter according to the third aspect, when the first inorganic material layer is provided on the outside, the above-mentioned dust-preventing effect is lost, but the effect of adsorbing gaseous impurities does not change so much, and the outer side of the air-purifying filter directly contacts air. The first inorganic material layer adsorbs and removes acidic and basic gaseous impurities in air, and the second inorganic material layer inside adsorbs and removes gaseous organic impurities in air.

Here, the frypontite mineral is a 1: 1 type whose composition formula is represented by the following formula (1) or (2).
(Double structure) A metal salt of aluminosilicate belonging to the serpentine subgroup clay mineral. As shown in FIG. 1, it has a double structure crystal in which one surface is solid basic and the other surface is solid acidic.

[0029]

Embedded image

Each surface of solid basic and solid acidic forms an adsorption site for each of acid and base. Noriyuki Takahashi, Masanori Tanaka, Teiji Sato, "Structure of Synthetic Flypontite", Journal of the Chemical Society of Japan, 1991, No. 7, p. 962
According to No. 967, the thickness of the unit layer of frypontite is 7.1 angstroms.

When the frypontite mineral is used to remove gaseous acidic impurities and gaseous basic impurities in the atmosphere as in the present invention, a fly having a two-layer structure as shown in FIG. The unit layer or at most several layers of pontite are dispersed in the space one by one without overlapping each other via, for example, inorganic fine particles, and the air to be treated is dispersed in the unit layer of each frypontite or It is essential to contact the adsorption sites present on the surface of the laminate of several layers. Therefore, the unit layer or several layers of fly pontites are uniformly distributed inside the porous structure (for example, the inorganic material layer of the present invention) through which air can easily flow, and the air to be treated is uniformly distributed. By entering and exiting through the pores of the porous structure, it is effectively contacted with adsorption sites existing on the surface of microcrystallites of frypontite (for example, a disk having a thickness of several tens angstroms and a diameter of 100 angstroms to 1 μm). Thereby, gaseous acidic impurities and gaseous basic impurities can be removed.

Since the microcrystallites of frypontite do not have micropores or mesopores which are involved in the physical adsorption of gaseous organic impurities, they do not adsorb gaseous organic impurities.
No ability to remove. In addition, since the frypontite mineral powder has no self-bonding property, a binder must be added in order to form the frypontite mineral powder into pellets or to fix it to the surface of the support in a layered manner. . In the present invention, the powder of the frypontite mineral is talc, kaolin mineral, bentonite, diatomaceous earth, silica, alumina, a mixture of silica and alumina, aluminum silicate, activated alumina, porous glass, and hydrous magnesium silicate having a ribbon-like structure. Using a powder of at least one inorganic substance such as clayey clay mineral, activated clay, and activated bentonite as a binder, the powder is fixed to the surface of a support to form an inorganic material layer or granulate to form pellets. As silica, for example, silica gel is used. As the alumina, for example, alumina gel is used. As a mixture of silica and alumina, for example, a mixed gel of silica gel and alumina gel is used.

In the air purifying filters according to the first to fifth aspects, as described in the sixth aspect, it is preferable that the support is a honeycomb structure. Further, as described in claim 7, it is preferable that the honeycomb structure is a structure containing inorganic fibers as an essential component. The adsorption layer having the honeycomb structure has a ceramic-like hard surface, and generates a very small amount of dust as compared with a conventional chemical filter using activated carbon impregnated with chemicals or ion exchange fibers. The air purification filter of the present invention is constituted by using not only the support but also the powder of the frypontite mineral as the adsorbent and the binder used for fixing the powder on the surface of the support as inorganic powder. There is no desorption of gaseous organic matter from the material. In this specification, the honeycomb structure is defined as
In addition to the so-called honeycomb structure, it includes all structures in which the cross section has a lattice shape, a wavy shape, or the like, and in which air can pass through cells which are elements of the structure. In the present invention, the support is not limited to the honeycomb structure. A three-dimensional network structure such as rock wool can also be suitably used as a support. In this case, as described later, it is preferable that the powder of the frypontite mineral, which is the adsorbent of the present invention, be fixed not only in the plane direction but also in the depth direction of the network structure. The method of adhering the adsorbent to the surface of the support may be a method of adhering with an inorganic powder binder, or a method of pelletizing the adsorbent powder of frypontite mineral using the inorganic powder as a binder to form pellets. ,
There is a method of bonding the pellet to the surface of the support.

Further, the invention of claim 8 relates to talc, kaolin mineral, bentonite, diatomaceous earth, silica, alumina, a mixture of silica and alumina, aluminum silicate, activated alumina, porous glass, and hydrous magnesium silicate having a ribbon-like structure. Pellets obtained by granulating the powder of fly ponite mineral using the powder of at least one of clayey clay mineral, activated clay, and activated bentonite as the binder, or powder of the mineral of fly pontite as the binder Diatomaceous earth, silica, alumina, a mixture of silica and alumina, aluminum silicate, activated alumina, porous glass,
An air purification filter characterized in that a casing is filled with second pellets coated with an inorganic powder comprising at least one of a hydrated magnesium silicate clay mineral having a ribbon-like structure, activated clay and activated bentonite. For example, silica gel is used as silica.
As the alumina, for example, alumina gel is used. As a mixture of silica and alumina, for example, a mixed gel of silica gel and alumina gel is used. In the air purifying filter according to the eighth aspect, the shape and size of the casing and the filling amount of pellets can be appropriately selected according to the shape and area of the air flow path and the installation conditions of the filter. Property is obtained.

According to a ninth aspect of the present invention, in the inorganic substance, the total volume of the pores distributed in the range of 15 to 300 Å is 0.2 cc / g or more per weight or the ratio of the pores. The surface area is preferably 100 m ² / g or more. In any case, the inorganic powder contained in the inorganic material layer and pellets used as the binder of the flypontite mineral powder has the ability to mechanically adhere the flypontite mineral powder to the surface of the support or the flypontite mineral powder. It has the ability as a binder when granulating tight mineral powder into pellets, and the target gas easily reaches the acidic and basic points present on the surface of the crystal layer of frypontite mineral. It has a porous structure that can be used.

Here, with respect to the inorganic powder used as the binder, the total volume of the pores distributed in the range of 15 to 300 Å and the specific surface area of the pores of the inorganic substance are expressed as follows:
Table 1 shows the results measured by the gas adsorption method.

[0037]

[Table 1]

As silica, silica gel was used as a powder sample. A powder of alumina gel was used as alumina. As a mixture of silica and alumina, a mixed gel of silica gel and alumina gel was used as a powder sample. 15 ~
The reason for focusing on pores distributed in the range of 300 Å is that pores having a size in this range excel at physical adsorption of gaseous organic impurities. The air to be treated can easily reach the adsorption sites existing on the surface of the microcrystallites of the frypontite through the air holes in the gaps formed adjacent to the frypontite mineral or the inorganic powder used as the binder. Acidic impurities and gaseous basic impurities are removed. At this time, gaseous organic impurities are removed by physical adsorption on the surface of the pores having the size in the above range existing on the surface of the inorganic powder used as the binder. In addition to the removal of gaseous acidic impurities and gaseous basic impurities, which is the main object of the present invention, it is possible to realize the simultaneous removal of gaseous organic impurities as a secondary effect of the pores of the inorganic powder used as the binder.

The specific surface area and pore volume of the binder of the group (I) are considerably larger than those of the binder of the group (II). Therefore, the physical adsorption ability of the gaseous organic impurities is much better for the binder (I) than for the binder (II). Binders such as talc, kaolin mineral and bentonite of the group (II) place importance on air permeability and are formed in the gap between adjacent binder fine particles or between the adjacent binder fine particles and the adsorbent fine particles carried on the support. The main size of the vent is 500
Angstrom or more. In other words, the air holes are macro holes that have very good air permeability but are unlikely to cause physical adsorption. In addition, there are not many pores that easily cause physical adsorption on the surface of the binder fine particles such as talc, kaolin mineral, and bentonite. The binder of the group (II) is used merely for mechanically supporting the powder of the frypontite mineral to be supported on the surface of the support. In this case, the binder is used to increase the ability to adsorb gaseous inorganic impurities. It is preferable that the loading amount of the pontitite mineral powder be as large as possible and the content ratio of the binder to the fly ponite mineral powder be as small as possible. However, if the content ratio of the binder is too small, fixation of the frypontite mineral powder to the surface of the support becomes incomplete, which causes peeling and dust generation. For example, in the case where a binder of bentonite and an inorganic fixing agent of silica are mixed with the frypontite mineral powder and fixed to the support, the content of the frypontite mineral powder in the inorganic material layer on the support surface (weight basis) )
If it exceeds 75%, the mechanical strength of the inorganic material layer on the surface of the support becomes weak, and the inorganic material layer cannot be put to practical use. That is,
The binder of the group (II) is required to have a capability of supporting the frying-pontite mineral powder and an excellent ventilation capacity so that the gas to be treated can easily reach the surface of the supported frying-pontite mineral powder. The ability to adsorb organic impurities is not required. On the other hand, when the binder of the group (I) is used, the air holes formed in the gaps between the adjacent binder fine particles or between the adjacent binder fine particles and the fly ponite mineral fine particles are (I).
It is the same as the binder of the group I). Therefore,
Since the gas to be treated has excellent gas permeability so that the gas to be treated can easily reach the powder surface of the frypontite mineral, gaseous acidic impurities and gaseous basic impurities can be found at the adsorption sites on the surface of the microcrystallite of the frypontite mineral. Is exhibited as in the case of the binder of the group (II).

The ease of physical adsorption of gaseous molecules is in the order of micropores, mesopores, and macropores, and macropores are said to hardly participate in physical adsorption. In the binders of the group (I), the pores which are liable to cause physical adsorption on the surface of the binder fine particles themselves, that is, micropores having a pore size of 20 Å or less,
Since there are mesopores, which are pores having a size of 0 Å to 500 Å, gaseous organic impurities that can contaminate the substrate surface, such as DOP, DBP, BHT, and siloxane, which cannot be adsorbed by the frypontite mineral, The binder particles are adsorbed and removed on the surface of the binder particles themselves by physical adsorption.

Also in the case of using the binder of the group (I), there is an upper limit on the content (by weight) of the frying ponite mineral powder in the inorganic material layer on the surface of the support. For example, when the frypontite mineral powder is fixed to the support using silica gel as a binder, the content of the frypontite mineral powder in the inorganic material layer on the support surface
If (by weight) exceeds 72%, the mechanical strength of the inorganic material layer becomes weak and cannot be put to practical use. However, an air purification filter using the inorganic powder of the group of (I) in Table 1 as a binder in claims 2 and 4,
In the air purifying filter of the third and fifth aspects, the support is covered with an inorganic material layer or a pellet for adsorbing and removing gaseous organic impurities. Therefore, even if the support contains an organic material capable of desorbing gaseous organic impurities, the gaseous organic impurities generated by the support itself are adsorbed and removed by the inorganic material layer or pellet covering the support. It does not go out into the air to be treated.

According to a tenth aspect of the present invention, at least one of the inorganic material layer, the first inorganic material layer, the second inorganic material layer, the pellet, the first pellet, and the second pellet is an inorganic material layer. A system fixing aid may be mixed. In this case, it is preferable that the inorganic fixing aid contains at least one of sodium silicate, silica and alumina. As silica, for example, silica sol is used. For example, alumina sol is used as alumina. In addition, in the invention according to the tenth aspect in which an inorganic fixing aid is added, the inorganic substance is not required to have much fixing and bonding ability. Further, when an inorganic substance capable of adsorbing an acid or a base is employed as a component of the adsorbing layer on the outside (on the side in contact with the airflow) according to the third and fifth aspects, the binder (inorganic substance) exerts an action of fixing and bonding exclusively. .

It is preferable that the air purifying filter of the present invention is composed of only a material that does not generate gaseous organic impurities, and is composed of only a material that does not contain combustible substances.

A twelfth aspect of the present invention is a powder of frypontite mineral, talc, kaolin mineral, bentonite, diatomaceous earth, silica, alumina, a mixture of silica and alumina, aluminum silicate, activated alumina, porous glass,
The support is impregnated with a suspension in which at least one inorganic powder of a hydrated magnesium silicate clay mineral having a ribbon-like structure, activated clay, and activated bentonite is dispersed, and the support is dried to form a support. A method for manufacturing an air purification filter, comprising fixing an inorganic material layer on a surface.

According to a thirteenth aspect of the present invention, the support is impregnated with a suspension in which the powder of the frypontite mineral and the inorganic powder as the binder are dispersed, and the support is dried to form a support. A first inorganic material layer is formed on the surface, and the support on which the first inorganic material layer is formed is further treated with diatomaceous earth, silica, alumina, a mixture of silica and alumina, aluminum silicate, activated alumina, porous After impregnating a suspension in which at least one inorganic powder of glass, hydrated magnesium silicate clay mineral having a ribbon-like structure, activated clay, and activated bentonite is dispersed, the suspension is dried and the surface of the first inorganic material layer is dried. After the second inorganic material layer is formed on the surface of the support, or after the second inorganic material layer is formed on the surface of the support, the first inorganic material layer is further formed on the surface of the second inorganic material layer. Features to form It is a manufacturing method of an air purifying filter.

According to the method for manufacturing an air purifying filter according to the twelfth or thirteenth aspect, the air purifying filter can be formed only of a material that does not generate gaseous organic impurities. Further, the air purification filter is substantially composed of only a material that does not contain combustibles. In the manufacturing method according to the twelfth or thirteenth aspect, for example, silica gel is used as silica. As the alumina, for example, alumina gel is used. As a mixture of silica and alumina, for example, a mixed gel of silica gel and alumina gel is used. When an inorganic material layer is formed on the surface of the support, or when one of the first inorganic material layer and the second inorganic material layer is formed on the other, the inorganic suspension in a sol state is added to the suspension. In the case of adhering fixing aid,
The inorganic material layer and the first and second inorganic material layers each contain an inorganic fixing aid.

According to a fourteenth aspect of the present invention, there is provided an advanced cleaning apparatus provided with a circulation path for circulating air in a space where a clean atmosphere is required.
The air purification filter according to any one of 4, 5, 6, 7, 8, 9, 10, and 11, and the removal of particulate impurities upstream of the space and downstream of the air purification filter. The filter is arranged. According to the advanced cleaning device of the present invention, the gaseous acidic impurities and gaseous basic impurities in the air circulating in the advanced cleaning device and, in some cases, the gaseous organic impurities are also removed. It is possible to prevent surface contamination due to the atmosphere of the substrate surface handled in the processing space in the advanced cleaning apparatus.

The high-purity cleaning apparatus according to the fourteenth aspect is excellent in disaster prevention because it does not use activated carbon or ion-exchange fiber, which is a combustible material.
The air purification filter and the filter for removing particulate impurities can be arranged on the ceiling of the space.

[0049]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, preferred embodiments of an air purification filter and a method for manufacturing the same according to the present invention will be described in detail with reference to the accompanying drawings. In the following description, the term “filter” refers to a filter for removing gaseous impurities, and the term “filter for removing particles” refers to a filter for removing particles.

FIG. 3 is a schematic exploded view of the filter 1 according to the embodiment of the present invention. As shown in the figure, a thin sheet 1 having no unevenness is provided between adjacent corrugated sheets 10.
Powdery frypontite mineral is talc, kaolin mineral, bentonite, diatomaceous earth, silica, alumina, a mixture of silica and alumina, aluminum silicate, activated alumina, porous glass A honeycomb structure 12 using at least one inorganic powder of a hydrated magnesium silicate clay mineral having a ribbon-like structure, activated clay, and activated bentonite as a binder.
It is configured to be fixed to the surface. For example, silica gel is used as silica. As the alumina, for example, alumina gel is used. As a mixture of silica and alumina, for example, a mixed gel of silica gel and alumina gel is used. Hereinafter, these inorganic powders used as binders are simply referred to as inorganic binders. That is, as shown in the figure, the filter 1 is constructed by assembling outer frames 15a, 15b, 15c, and 15d made of aluminum so as to open in the flow direction of the processing air (the direction indicated by the white arrow 13 in the drawing). Sheet 10 and thin sheet 1 in which powdery frypontite is fixed to the surface using an inorganic binder
1 are alternately stacked substantially parallel to the air flow direction 13. The outer shape and dimensions of the filter 1 can be arbitrarily designed according to the installation space.

Here, an example of a method for manufacturing the filter 1 will be described. First, three materials of inorganic fiber (ceramic fiber, glass fiber, silica fiber, alumina fiber, etc.), organic material (mixture of pulp and molten vinylon) and calcium silicate are blended in an equal weight of 1: 1: 1 and wet-processed. The paper is formed to a thickness of about 0.3 mm by a paper making method. Instead of calcium silicate, a fibrous crystal clay mineral such as sepiolite or palygorskite containing magnesium silicate as a main component may be used. This paper sheet is corrugated by a corrugator, and the resulting corrugated sheet 10 is bonded to a thin sheet 11 made of the same material into a thin sheet shape with an adhesive to obtain a honeycomb structure 12 as shown in FIG. This honeycomb structure 12 was placed in an electric furnace at about 400 ° C. for 1 hour.
A heat treatment is performed for about an hour to remove all organic components. After the organic components are removed, countless micron-sized depressions remain on the surface of the honeycomb structure, and the porous honeycomb structure 12 having the depressions as holes can be manufactured. Later, the fine particles of the adsorbent and the inorganic binder will fit into the depression. Next, the powder of the frypontite mineral and the suspension in which the inorganic binder is dispersed,
The honeycomb structure 12 was immersed for several minutes, lifted up, and dried by heat treatment at about 300 ° C. for about 1 hour, and as shown in FIG. The filter 1 can be obtained by forming the inorganic material layer 20 by being fixed by using. The suspension may contain an inorganic fixing aid, for example, sodium silicate or at least one of silica and alumina. For example, silica sol is used as silica. For example, alumina sol is used as alumina. The role of the inorganic fixing aid is that the powder of the frypontite mineral and the inorganic binder form the honeycomb structure 1
2 functions as an auxiliary agent for firmly adhering to the surface (including the inner surface of the cell serving as an element of the honeycomb structure 12 (the same applies hereinafter)). The filter 1 thus obtained does not contain flammable substances in the constituent material, and all the gaseous organic impurity components causing surface contamination contained in the constituent material when the filter is heat-treated are desorbed and removed. Therefore, no gaseous organic impurities are generated from the filter 1 itself.

Next, another method of manufacturing the filter 1 will be described. Until the honeycomb structure 12 is manufactured, the manufacturing method is the same as the above-described manufacturing method, and a description thereof will be omitted. This manufacturing method is characterized in that pellets produced by granulating frypontite mineral powder are adhered to the surface of the honeycomb structure 12 with an adhesive. When granulating frypontite mineral powder, clay-like viscosity and plasticity are exhibited when the frypontite mineral powder and an inorganic binder are mixed with an appropriate amount of water and an inorganic fixing aid mixed. And granulation becomes possible. The types of the inorganic binder and the inorganic fixing aid are the same as those in the production method described above.

Next, another method of manufacturing the filter 1 will be described. The completely different point from the above-mentioned manufacturing method is the structure of the surface of the pellet. The surface of the pellet is coated with an inorganic adsorption powder, and the surface of the pellet is formed with an inorganic material layer that adsorbs and removes gaseous organic impurities.

FIG. 5 is a partially enlarged cross-sectional view of a filter 1 having a structure in which pellets 21 obtained by granulating powder of frypontite mineral using an inorganic binder are fixed to the surface of a honeycomb structure 12. Pellets 21 obtained by granulating powder of frypontite mineral using an inorganic binder are fixed to the entire surfaces of the corrugated sheet 10 and the thin sheet 11 with a nonflammable adhesive. In this embodiment, the processing air passes through a thin cylindrical portion 17 having a pseudo-half moon-shaped cross section. Then, the honeycomb structure 12 to which the pellets 21 are fixed is placed in an electric furnace and subjected to a heat treatment at about 100 ° C., which is lower than the heat resistant temperature of the adhesive, for about 2 hours. The filter 1 can be manufactured by desorbing and removing all the gaseous organic impurity components.

The filter 1 thus manufactured is
Because the constituent materials do not contain flammable materials, the filter 1 installed on the ceiling surface has better disaster prevention than the conventional chemical filter based on flammable activated carbon or ion-exchange fiber installed on the ceiling surface. The above security is significantly increased. Note that the cross-sectional shape of the space through which the processing air passes is not limited to the half-moon shape as described above, and may be any shape.

FIG. 6 is a partially enlarged view of the section of the inorganic material layer showing the inorganic material layer in which the powder of frypontite mineral according to the present invention is supported on the surface of the support with an inorganic binder. The gas to be treated flows from the surface of the inorganic material layer (the contact surface with the gas to be treated) to the inside of the inorganic material layer so as to pass through the pores formed between the fine particles of the frypontite mineral and the fine particles of the inorganic binder. It enters into the material or conversely goes out from the inside of the inorganic material layer. At that time, gaseous acidic impurities and gaseous basic impurities are removed from the frypontite mineral particles, and molecules of the gaseous organic impurities enter the pores suitable for physical adsorption existing on the surface of the binder particles and are removed by adsorption. Is done.

In order to achieve the first object of the present invention, ie, the removal of gaseous acidic impurities and gaseous basic impurities, and to achieve the second object, simultaneous removal of gaseous organic impurities, the mesopore region is mainly used. Alternatively, the filter 1 may be formed by fixing the powder of the frypontite mineral to the honeycomb structure 12 as an inorganic material layer 20 using an inorganic binder having pores in a micropore region, The mineral powder is formed into pellets 21 and the pellets 21 are fixed to the surface of the honeycomb structure 12 to constitute the filter 1.

Further, as shown in the AA section and the BB section in FIG. , A pellet 2 having a double cylindrical casing 2 having a number of vents 23 on its side.
The object of the present invention can also be achieved by forming the filter 1 'by filling the inside of the filter 2'. The processing air flows in from the inner cylinder of the casing 22, passes through the packed layer of the pellets 21 in the casing 22, and then exits through the space between the outer cylinder of the casing 22 and the outer cylinder 24. The flow direction of the processing air is indicated by arrow 13.

Here, the method of synthesizing microcrystallites of frypontite in which several to several tens of unit layers of frypontite having a two-layer structure shown in FIG. And Noriyuki Takahashi, Masanori Tanaka, Teiji Sato, "Synthesis of Flypontite", The Chemical Society of Japan, 199
0, No. 4, p. Details are described in 370-375.

The thus-obtained, for example, disk-shaped synthetic frypontite microcrystal powder having a thickness of several tens angstroms and a spread diameter of 100 angstroms to 1 μm is treated with a powdery acid having a particle diameter of several tens nm. It is mixed with an inorganic binder of montmorillonite (activated clay) and fixed to the surface of the honeycomb structure 12 or this mixture is pelletized.
The filter 1 or 1 ′ according to the present invention can be manufactured by fixing to the surface of the honeycomb structure 12 or filling in the casing. Montmorinite is Al ₄ Si ₈ (OH) 4 · produced in Montmorion, France.
nH ₂ O is a name given to a clay mineral having a chemical composition of:
00 Å pore volume of about 0.37 cc /
g, specific surface area is about 300 m ² / g. The ratio of the pore volume in the range of 40 Å to 600 Å of the pore volume in the entire pore volume is as high as 22%, and by using acid-treated montmorillonite (activated clay) as a binder for the powder of frypontite mineral, Gaseous organic impurities that cannot be adsorbed by the frypontite mineral alone can be physically adsorbed in the pores of the binder.

Of the binders of the group (II) in Table 1, talc and kaolin minerals have a large crystallite size and a large volume in the macropore region, but have a small internal surface area and volume in the micropore region and the mesopore region. ， Physical adsorption capacity is also small. Among the binders of the group (II), bentonite also has a large volume in the macropore region, but has a small internal surface area and volume in the micropore region and the mesopore region, and has a small physical adsorption capacity. On the other hand, among the binders of the group of (I) in Table 1,
For example, the pores of sepiolite, a hydrated magnesium silicate clay mineral with a ribbon-like structure, consist of 10 Å micropores and 200 Å mesopores.
The internal surface area and volume of the micropore region and the mesopore region are large, and the physical adsorption capacity is large. Binders of the group (I), namely diatomaceous earth, silica (silica gel), alumina (alumina gel), a mixture of silica and alumina (a mixed gel of silica gel and alumina gel), aluminum silicate, activated alumina, porous glass, ribbon Hydrated magnesium silicate clay mineral with a flake-like structure, acid-treated montmorillonite (activated clay),
Activated bentonite inorganic powder has a large physical adsorption capacity. As shown in Table 1, each of these minerals
0.2 cc / g of pore volume per unit weight distributed in the range of 15 Å to 300 Å
Or the specific surface area is 100 m ² / g or more. Needless to say, these inorganic powders can be suitably used as a second inorganic material layer which is formed so as to overlap with the first inorganic material layer containing the powder of frypontite mineral.

A pellet prepared by granulating the frypontite mineral powder using a frypontite mineral powder and an inorganic binder having an effective pore diameter in a mesopore region or a micropore region is provided for fixing to a support. In an embodiment, the powder of the frypontite mineral and the powder of the inorganic substance are mixed with, for example, city water to form a clay,
Granulate to about 0.8 mm pellets with a granulator. This is sprayed on a support to which an inorganic and nonflammable adhesive has been applied in advance using high-speed air, whereby the filter of the present invention as shown in FIG. 5 can be manufactured. The support is not necessarily limited to the honeycomb structure, but may be a three-dimensional network structure such as rock wool. In the latter, the air to be treated passes across the network structure, so that the air resistance is large, but the chance of contact with the pellets of the fly pontitite mineral is larger than that of the honeycomb structure.

FIG. 8 is a schematic exploded view of a filter 31 according to another embodiment of the present invention. In this filter 31, the configuration of the honeycomb structure 12 itself is the same as the configuration of the filter 1 described above with reference to FIG.
The detailed description is omitted by attaching the same reference numerals as in FIG.

In this filter 31, as shown in FIG. 9, the powder of frypontite mineral is fixed to the surface of the honeycomb structure 12 in which the corrugated sheet 10 and the thin sheet 11 are laminated by using an inorganic binder. Inorganic material layer 25
Is formed, and an inorganic powder having an effective pore diameter in a mesopore region or a micropore region is fixed on the surface thereof to form a second powder.
The inorganic material layer 26 is formed. Less than,
The inorganic powder having an effective pore diameter in the mesopore region or the micropore region is referred to as “inorganic adsorption powder”. Filter 31
The external shape and dimensions can be arbitrarily designed according to the installation space. The pore size of the inorganic binder used when forming the first inorganic material layer 25 is different from that of the inorganic adsorption powder used when forming the second inorganic material layer 26, and is different from the macroscopic powder which does not participate in physical adsorption. It may be a hole area. For example, clay minerals such as talc, kaolin mineral and bentonite in the group of (II) in Table 1 hardly have pores involved in physical adsorption, but can be used as a binder for the first inorganic material layer 25. Also, sodium silicate,
An inorganic fixing aid such as silica or alumina may be used. As silica, for example, silica sol is used. For example, alumina sol is used as alumina. However, silica sol and alumina sol are suspensions containing monodispersed nanometers to tens of nanometers of primary particles, but when fixed to the surface of the support and dried, they are three-dimensional aggregates in which the primary particles are aggregated It changes to silica gel or alumina gel and has the ability to adsorb gaseous organic impurities. Therefore, the inorganic fixing aids of silica sol and alumina sol are used alone,
It can be used in exactly the same manner as silica gel or alumina gel used as a binder for adsorbing gaseous organic impurities of the first inorganic material layer 25, and as an inorganic substance for adsorbing gaseous organic impurities of the second inorganic material layer 26. It can be used in exactly the same way as the silica gel or alumina gel used. That is,
The first inorganic material layer 25 functions to remove gaseous acidic impurities and gaseous basic impurities in the atmosphere, and the second inorganic material layer 26 only needs to function to adsorb and remove gaseous organic impurities. . Further, the powder of the fly pontitite mineral contained in the first inorganic material layer 25 has a layer structure of the fly pontite, so that dust is easily generated due to peeling of the layer. If the first inorganic material layer 25 is covered (coated) with the second inorganic material layer 26, such a problem does not occur. FIG. 10 is a partially enlarged view of a cross section of a composite layer including a first inorganic material layer and a second inorganic material layer according to the present invention.

In FIG. 10, even when gaseous organic impurities are desorbed from the support itself by including the organic material in the support, the second inorganic material layer 26 covering the support supports the support. Since the gaseous organic impurities desorbed from the substrate are adsorbed and removed, the gaseous organic impurities generated from the support do not penetrate through the second inorganic material layer 26 and enter the air to be treated.

Here, an example of a method for manufacturing the filter 31 will be described. First, the porous honeycomb structure 12 is manufactured. Until the inorganic material layer is formed, the method is the same as that described above, and a description thereof will be omitted. Next, the honeycomb structure 12 is added to a suspension in which a powder of the frypontite mineral and an inorganic binder such as talc, kaolin mineral and bentonite are dispersed.
Is immersed for several minutes, and dried by a heat treatment at about 300 ° C. for about 1 hour to form a first inorganic material layer 25. Next, an inorganic powder having an effective pore size in the mesopore region or micropore region, for example, diatomaceous earth, silica, alumina, a mixture of silica and alumina, aluminum silicate, activated alumina, porous glass, and hydrated silica having a ribbon-like structure The honeycomb structure 12 after forming the first inorganic material layer is immersed in a suspension in which a magnesium clay mineral, activated clay, activated bentonite, and the like are dispersed for several minutes, and is then heated at about 300 ° C. for about one hour. After drying by heat treatment, the second inorganic material layer 26 is formed. As silica, for example, silica gel is used. As the alumina, for example, alumina gel is used. As a mixture of silica and alumina, for example, a mixed gel of silica gel and alumina gel is used. Examples of the hydrated magnesium silicate clay mineral having a ribbon-like structure used for forming the second inorganic material layer 26 include sepiolite and palygorskite. Thus, the first inorganic material layer 2
The honeycomb structure 12 in which the second inorganic material layer 26 is coated on the honeycomb structure 5 can be obtained. The inorganic powder used for forming the first inorganic material layer 25 and the second inorganic material layer 26 may contain at least one inorganic fixing aid such as sodium silicate, silica or alumina. . As silica, for example, silica gel is used. As the alumina, for example, alumina gel is used. The role of the inorganic fixing aid is as follows.
The frypontite mineral powder and the inorganic binder forming No. 5 function as an auxiliary agent for firmly fixing the pores of the honeycomb structure 12 and the like, and further form the second inorganic material layer 26. The inorganic adsorbed powder functions as an auxiliary agent for firmly fixing the first inorganic material layer 25 to the first inorganic material layer 25. The honeycomb structure 12 thus obtained does not contain combustible materials in the constituent materials, and removes all the gaseous organic impurity components which cause surface contamination and are contained in the constituent materials when the honeycomb structure 12 is subjected to the heat treatment. Since the honeycomb structure 12 is separated and removed, no gaseous organic impurities are generated from the honeycomb structure 12 itself. Further, as the material of the outer frame 15 shown in FIG. 8, it is preferable to use a material such as aluminum which does not generate gaseous organic substances and does not contain combustible substances. Also,
Adhesives and sealants used for fixing the honeycomb structure 12 to the outer frame 15 and for closing the gap between the honeycomb structure 12 and the outer frame 15 also do not generate gaseous organic substances and contain combustible substances. Preferably, it has no properties. In this case, for example, the outer frame 15 is attached to the honeycomb structure 12 and heat treatment is performed on the entire filter 31 that has been assembled, and the non-combustible adhesive or sealant, which is a constituent material of the filter 31, causes surface contamination. All gaseous organic impurity components may be desorbed and removed. In this way, the entire filter 31 can be made of only a material that does not contain combustibles, or can be made of only a material that does not generate gaseous organic impurities.

Next, another method of manufacturing the filter 31 will be described. A three-dimensional network structure such as a honeycomb structure or rock wool manufactured by the above-described manufacturing method is used as a support. Then, in this example of the production method, granular flypontite mineral is adhered to the surface of the support with an adhesive. As for the granular frypontite mineral, an inorganic binder is mixed with the frypontite mineral powder, and the mixture is molded into a pellet shape. A frypontite mineral pellet with a coating layer in which a coating layer is formed by coating an inorganic powder having an effective pore diameter in a mesopore region or a micropore region around the pellet is prepared in advance. In order to form a coating layer of inorganic powder, the pellets are immersed in a suspension of the inorganic powder for coating dispersed in a pellet-shaped frypontite mineral, then pulled up and dried. Done. In order to increase the mechanical strength of the coating layer, a sol-like inorganic fixing aid is dispersed in the suspension together with the inorganic powder for coating, and the inorganic fixing aid is added to the inorganic powder coated on the pellets. An agent may be included. The types of the inorganic powder and the inorganic fixing aid for coating are as described above.

FIG. 21 is an explanatory view schematically showing a configuration of an advanced cleaning apparatus 100 according to an embodiment of the present invention.
The advanced cleaning device 100 is, for example, a clean room or a clean bench. Advanced cleaning equipment 1
Reference numeral 00 denotes a processing space 102 for manufacturing, for example, an LSI or LCD, a ceiling (supply plenum) 103 and a lower floor (return plenum) 104 located above and below the processing space 102, and a side of the processing space 102. Is formed from the urethane passage 105 located on the side.

The ceiling unit 103 has a fan unit 110
111 for removing gaseous impurities having air permeability
And a clean fan unit 113 having a filter 112 for removing particles. In the processing space 102, for example, a semiconductor manufacturing apparatus 114 serving as a heat generation source is installed. The lower floor 104 is partitioned by a grating 115 having a large number of holes. The lower floor 1
In 04, a dry coil 116 for processing a thermal load of the semiconductor manufacturing apparatus 114 is provided. The dry coil 116 is an air cooler that cools air under conditions that do not cause condensation on the heat exchange surface. Retan passage 105
Is provided with a temperature sensor 117, so that the temperature detected by the temperature sensor 117 becomes a predetermined set value.
The cold water flow control valve 118 of the dry coil 116 is controlled.

By operating the fan unit 110 of the clean fan unit 113, the air inside the advanced cleaning apparatus 100 is adjusted to the ceiling 103 → the processing space 102 → the lower floor 104 →
It is configured to flow and circulate in the order of the urethane passage 105 → the ceiling 103. Further, during this circulation, the cooling is performed by the dry coil 116 and the clean fan unit 1 is cooled.
The gaseous impurities and particulate impurities in the air are removed by the filter 111 for removing gaseous impurities and the filter 112 for removing particles in the inside 13 so that clean air at an appropriate temperature is supplied into the processing space 102. Has become.

The filter 111 for removing gaseous impurities is
An air purification filter containing the above-described frypontite mineral powder according to the present invention, which removes gaseous acidic and basic impurities and possibly gaseous organic impurities from circulating air. The air purification filter 111 is
It is composed only of a material that does not contain combustibles and is composed only of a material that does not generate gaseous organic impurities.

The filter 112 for removing particles is arranged on the downstream side of the air purification filter 111.
2 has a function capable of removing particulate impurities. Further, the particle removing filter 112 is made of only a material that does not generate gaseous organic impurities.

The lower part 104 of the advanced cleaning device 100
Inside, the intake outside air is appropriately supplied through the air passage 120. The air flow path 120 is also provided with an air purification filter 121 according to the present invention for removing gaseous impurities from the taken-in outside air. A unit type air conditioner 122 for controlling humidity is provided. Further, a humidity sensor 127 is disposed in the air flow path 120, and a water supply pressure adjusting valve of a humidity control unit of the unit type air conditioner 122 so that the humidity detected by the humidity sensor 127 becomes a predetermined set value. 129 is controlled. On the other hand, in the processing space 102, a humidity sensor 128 is installed.
At 28, the humidity of the atmosphere in the processing space 102 is detected.

The intake outside air supplied from the air passage 120 to the lower floor 104 of the advanced cleaning device 100 is introduced into the processing space 102 via the retentate passage 105 and the ceiling 103. Then, an amount of air corresponding to the intake outside air is exhausted from the exhaust port 125 to the outside of the room through the exhaust gallery 126.

The air purification filter 111 according to the present invention
When the air purification filter 111 is mounted on the ceiling surface as shown in FIG. 21 because a constituent material does not contain combustible materials, a conventional chemical filter based on activated carbon or ion exchange fiber as a combustible material is mounted on the ceiling surface. Compared to the case,
Disaster prevention safety is greatly improved. In the advanced cleaning apparatus 100 shown in FIG. 21, if the air purification filter 121 for treating the intake outside air has the same configuration as the air purification filter 111 for treating the circulating air, the activated carbon and the ion-exchange fiber, which are combustibles, can be used. Compared to the case where a conventional chemical filter as a base was attached to the outside air intake,
Safety in disaster prevention is further enhanced.

Medium-performance filter for removing ordinary particles, HE
The PA filter or ULPA filter uses a filter material binder containing volatile organic material as the fiber filter material, or uses a sealing material containing volatile organic material to bond the fiber filter material and the filter frame material. There is degassing from the agent. Therefore, the filter 112 for removing particles constituting the present invention uses a filter medium that does not use a filter medium binder containing a volatile organic substance, or performs baking even if a filter medium binder containing a volatile organic substance is used. Use a filter medium from which volatile organic substances have been removed, and select a type that does not generate degassing for the sealing material that is a means for fixing the filter medium to the frame. It is desirable to fix it to the frame.

Next, an advanced cleaning apparatus 100 ′ according to another embodiment of the present invention is shown in FIG. In the advanced cleaning apparatus 100 ′ shown in FIG. 22, the air purification filter 111 of the honeycomb structure containing the powder of the frypontite mineral according to the present invention is not attached to the entire surface of the ceiling 103 of the advanced cleaning apparatus 100 ′, but is thinned out in places. Is installed.
In this example, the number of installed air purification filters 111 is reduced by half as compared with FIG. The other points are the same as those of the advanced cleaning apparatus 100 described above with reference to FIG.
Therefore, in the advanced cleaning device 100 'shown in FIG.
The same components as those of the advanced cleaning device 100 described above with reference to FIG. 21 are denoted by the same reference numerals, and detailed description thereof will be omitted.

Chemical contaminants to be removed by the air purification filter of the present invention are acidic substances, basic substances, dopants, and organic substances. To explain a typical failure case, acid gas, especially hydrofluoric acid (HF), promotes the volatilization of boron (B) from glass fiber, which is a filter medium for removing particles, and basic gas impedes the resolution of resist. Become. Boron (B)
And phosphorus (P) cause a malfunction of the semiconductor device. In particular, boron (B) contaminates the channel region of the TFT transistor and causes deterioration of transistor characteristics.
When a gaseous organic substance adheres to the substrate surface, a defective insulating oxide film, poor adhesion of a resist film and a high surface resistance value tend to cause electrostatic adsorption of fine particles. Further, gaseous organic substances cause clouding of lenses and mirrors of the exposure apparatus. Sources of these gaseous impurities include a source existing inside the advanced cleaning device such as a cleaning device, a worker, and a member of a clean room, and contaminants derived from outside air entering the advanced cleaning device from the outside. Therefore, the role of the air purification filter 111 is to mainly remove gaseous contaminants generated inside the advanced cleaning device from the circulating air and reduce the concentration of these gaseous contaminants inside the advanced cleaning device. On the other hand, the role of the air purification filter 121 disposed in the air passage 120 is to remove contaminants derived from the outside air entering the advanced cleaning device from the outside and reduce the concentration of these gaseous contaminants inside the advanced cleaning device. That is. When the advanced cleaning apparatus equipped with the air purification filters 111 and 121 is operated, the concentration of the chemical contaminants inside the advanced cleaning apparatus is highest in the initial operation, and these chemical contaminants are removed one by one from the circulating air as the operation time elapses. As a result, the concentration decreases, and finally stabilizes at a concentration equilibrium with the amount generated inside the advanced cleaning device. The amount of the chemical contaminants removed when the air circulates once is determined by the advanced cleaning apparatus 100 shown in FIG. 21 attached to the entire ceiling and the advanced cleaning apparatus 10 shown in FIG.
When 0 'is compared, there is a 2: 1 relationship. That is, the time required to reach the concentration equilibrium with the amount generated inside the advanced cleaning device from the highest concentration at the beginning of operation is equal to that of the thinned advanced cleaning device 100 'in FIG.
It is considerably longer than in the case of the first advanced cleaning device 100.
In addition, the ultimately reached equilibrium concentration is slightly higher when thinned out than when mounted on the entire ceiling. That is,
Although it takes time to reduce the concentration when thinning is performed, and the equilibrium concentration after the reduction is slightly higher than the case where it is not thinned, it is desired to reduce the initial cost of the air purification filter 111 and the running cost associated with periodic replacement. Due to economic demands, the number of installed air purification filters 111 is often reduced as in the example shown in FIG.

[0079]

Next, the operation and effect of the filter according to the embodiment of the present invention described above will be described with reference to examples.

First, in a clean room, two types of commercially available chemical filters using granular activated carbon and fibrous activated carbon to which chemicals are attached to remove gaseous inorganic impurities, and a chemical filter using ion exchange fibers are used. Clean room air treated and Fig. 8
In a total of four atmospheres of clean room air treated by the filter according to the present invention shown in FIG. 4, the change over time of the contact angle of the surface of the silicon wafer with the oxide film was measured. The results are shown in FIG.

The contact angle shown in FIG. 11 was measured by dropping ultrapure water on the surface of the substrate. This contact angle is an index for easily evaluating the degree of organic substance contamination on the substrate surface. Immediately after cleaning, the surface of a silicon wafer or glass with an oxide film free from organic contamination is easily water-compatible, that is, hydrophilic, and has a small contact angle. However, those surfaces contaminated with organic matter are water-repellent, that is, water-repellent, and have a large contact angle. For example, for a glass substrate surface left in a clean room atmosphere, a measured value of a contact angle by dropping of ultrapure water and an X-ray photoelectron spectroscopy (XPS: X-ray)
Photoelectron Spectroscope
It is known that the organic substance surface contamination measured in y) has a correlation as shown in FIG. For the surface of the silicon wafer with an oxide film, there is almost the same correlation between the contact angle and the organic surface contamination. Thus, there is an extremely strong correlation between the magnitude of the contact angle of water on the substrate surface and the contamination of the organic substance surface.

The following can be understood from the results shown in FIG. Since the ion-exchange fiber is originally intended to adsorb and remove water-soluble inorganic impurities, it cannot adsorb organic substances in the air to be treated. On the contrary, the ion exchange fibers themselves generate new gaseous organic substances. An increase in the contact angle of about 10 ° after one day of standing is observed. Even two types of activated carbon filters for the purpose of preventing gaseous inorganic impurity contamination cannot adsorb organic substances in the air to be treated. On the contrary, since the activated carbon filter itself generates new gaseous organic substances, the contact angle increases by about 10 ° in one day. In the filter according to the present invention shown in FIG. 8, even if the wafer surface is left for one day, the contact angle hardly increases, the organic substances in the air to be treated are absorbed and removed, and the filter itself generates new gaseous organic substances. It was clear that not.

In the case of the activated carbon filter, it is included in an adhesive for adhering the constituent material or the activated carbon to the sheet or a sealing material used to fix the filter medium to the surrounding frame. In the case of the ion exchange fiber filter, it is included in the polymer fiber of the constituent material. Gaseous organic impurities generated from various additives are contained in the air after passing through the chemical filter. Further, in the ion-exchange fiber filter, a part of the ion-exchange groups may be eliminated as sulfonic acid, carboxylic acid, phosphoric acid, ammonia or amine. In other words, these conventional chemical filters remove gaseous organic impurities generated from the chemical filter itself while removing very small amounts of acidic or basic impurities in the order of ppb or dopants in the order of ppt contained in the clean room atmosphere. It will be mixed into the passing air. On the contrary, the use of a conventional chemical filter sometimes increases the concentration of gaseous organic substances that cause substrate surface contamination in a clean room atmosphere.

Clean room air containing several hundred ppt to several ppb of HCl, NH ₃ , DOP, and pentamer siloxane (D5) was passed through the two types of filters a and b of the honeycomb structure according to the present invention. The concentrations of HCl and NH ₃ in the respective atmospheres on the upstream and downstream sides of the honeycomb structure were measured by ion chromatography (IC) to measure the respective removal efficiencies. Furthermore, the amount of organic substance surface contamination due to DOP and D5 on the surface of the silicon wafer placed in the respective atmospheres on the upstream and downstream sides of the honeycomb structure was measured and compared to evaluate the effect of preventing organic substance surface contamination. Further, the concentration of suspended fine particles (the number of particles having a particle diameter of 0.1 μm or more contained in a space of 1 ft ^{3) in} each atmosphere on the downstream side of the honeycomb structure was measured. The concentration of suspended particulates on the upstream side was 10 particles / ft ³ . Table 2 shows the results.

[0085]

[Table 2]

A 4-inch p-type silicon wafer was used to evaluate the amount of organic surface contamination. The cleaned wafer was exposed on the upstream and downstream sides of the filter, respectively, and the surface contamination was measured. For analysis and measurement of organic substances attached to the wafer surface,
A temperature rising gas desorption device and a gas chromatograph mass spectrometer were used in combination. In addition, the surface contamination prevention rate was determined as follows based on gas chromatography. Surface contamination prevention rate = (1− (B / A)) × 100
(%) A: Area of the peak of the contaminated organic substance detected from the wafer surface on the upstream side B: Area of the peak of the contaminated organic substance detected from the wafer surface on the downstream side

As shown in FIGS. 3 and 8, each of the two types of filters a and b according to the present embodiment has a structure in which a thin sheet having no irregularities is sandwiched between adjacent corrugated sheets.
The thickness of the filter in the ventilation direction is 10 cm, and the ventilation air velocity is 0.
6 m / s, the total surface area of the sheet per unit volume of the filter in contact with the processing air passing through the filter is 3000 m ² /
It was m ^3.

The filter a of the present invention is composed of artificially synthesized frypontite microcrystallites (thickness of several tens angstroms and spread diameter of 100 angstroms to 1 μm).
Is mixed with a 3 μm powder of kaolinite as an inorganic binder, and the porous honeycomb structure is immersed in a slurry dispersed with silica sol as an inorganic fixing aid, and then dried. A first inorganic material layer was formed. Next, the first inorganic material layer was formed in a slurry in which activated clay 3 μm powder having an effective pore diameter of mainly 20 Å to 1000 Å was dispersed together with silica sol as an inorganic fixing aid. And then dried to form a second inorganic material layer. The thickness of the first inorganic material layer is 100 μm, and its weight composition ratio is frypontite mineral: kaolinite: silica = 70%: 25%: 5
%, And the thickness of the second inorganic material layer is 10 μm.
Its weight composition ratio is acid-treated montmorillonite: silica = 8
7%: 13%. 230g filter density
/ Liter, of which the density occupied by the inorganic material layer is 90 g
Per liter (39% of the total filter).

The filter b of the present invention is obtained by mixing the above-mentioned powder of the frypontite mineral with an inorganic binder of 3 μm kaolinite, and dispersing silica sol together as an inorganic fixing agent. After dipping the structure, it was dried and manufactured. The kaolinite used for the filter b has no major pores other than vents having a size of 1000 angstroms or more, and thus has little ability of physical adsorption. On the other hand, the activated clay used for the filter a has an effective pore diameter of mainly 20 angstrom or more.
It is distributed at 1000 angstroms, and its physical adsorption capacity is comparable to activated carbon.

The difference between the filters a and b of the present invention is that the filter b does not have a material corresponding to the second inorganic material layer (active clay layer) like the filter a. It is clear from Table 2 that the removal of gaseous inorganic impurities such as HCl and NH ₃ is effective only with the first inorganic material layer containing the powder of frypontite mineral. Does not affect their removal efficiency. However, among the organic contaminants detected from the substrate surface in the advanced cleaning apparatus, DOP and pentamer siloxane (D5), which are the most abundant, are used as the second inorganic material layer having excellent physical adsorption ability. The removal efficiency differs greatly depending on the presence or absence.
That is, the filter a provided with the second inorganic material layer can collectively remove not only gaseous inorganic impurities but also gaseous organic impurities.

Next, various types of filters manufactured according to the present invention were compared. Table 3 shows the results.

[0092]

[Table 3]

In Table 3, according to the present invention A, powder of frypontite mineral was fixed to the surface of the honeycomb structure by mixing kaolinite as a binder and alumina sol as an inorganic fixing aid, and An air purification filter having a layer formed thereon.

In the present invention B, an alumina sol as an inorganic fixing aid is mixed and fixed on the surface of the honeycomb structure with a powder of frypontite mineral and a binder of acid-treated montmorillonite (activated clay), and the inorganic material layer is fixed. This is a filter formed with. The present invention C is a filter in which a second inorganic material layer is further formed on the surface of the filter of the present invention A with an acid-treated montmorillonite powder. The present invention D is a filter in which a second inorganic material layer is further formed on the filter surface of the present invention B by acid-treated montmorillonite powder. In the present invention E, first, an inorganic material layer made of an acid-treated montmorillonite powder is formed on the surface of the honeycomb structure, and further, the fly ponite mineral powder is applied on the kaolinite as a binder and the inorganic-based fixing auxiliary on the inorganic material layer. This is a filter having an inorganic material layer formed by mixing alumina sol as an agent. That is, the order of fixing the first inorganic material layer and the second inorganic material layer of the present invention C to the surface of the honeycomb structure is changed. In the present invention F, first, an inorganic material layer made of an acid-treated montmorillonite powder is formed on the surface of the honeycomb structure, and further overlaid thereon, a fly of an acid-treated montmorillonite binder and alumina sol, which is an inorganic fixing aid, are added. This is a filter in which another inorganic material layer is formed by mixing pontite mineral powder. That is, the order of fixing the first inorganic material layer and the second inorganic material layer of the present invention D to the surface of the honeycomb structure is changed.

The structure of the inorganic material layer of each of these filters is shown as an enlarged sectional view in FIGS. In order to make it easier to understand the structure of the inorganic material layer, a schematic perspective view is also shown using FIG. 15 as an example. In these figures, the inorganic material layer shown in FIG. 6 or FIG. 10 is cut into a cylindrical shape having a thickness of the inorganic material layer, and pores existing in the cylinder are used for physical adsorption of gaseous organic impurities. The distribution of micropores and mesopores, which are involved pores, is represented by thin pores, and the distribution of macropores, which hardly contributes to physical adsorption of gaseous organic impurities, is represented by thick pores. It is shown.

According to the present invention A, as shown in FIG. 13, the inorganic material layer 51 containing the powder of frypontite mineral has no major pores other than vents having a size of 1000 Å or more. There is little ability to physically adsorb gaseous organic impurities. The present invention B, as shown in FIG.
The inorganic material layer 52 containing the powder of frypontite mineral has about 15 to 300
It has pores of about angstrom and has the ability of physical adsorption. Invention C, as shown in FIG.
First inorganic material layer 5 containing frypontite mineral powder
No. 3 has no major pores other than vents having a size of 1000 angstroms or more. Therefore, the second inorganic material layer 54 has little ability of the physical adsorption, but does not contain the powder of frypontite mineral. The surface of fine particles of acid-treated montmorillonite has pores of about 15 to 300 angstroms, and has the ability of physical adsorption. In the present invention D, as shown in FIG. 16, the acid-treated montmorillonite powder is applied to both the first inorganic material layer 55 containing the frypontite mineral and the second inorganic material layer 56 not containing the frypontite mineral powder. Therefore, both of the inorganic material layers have the physical adsorption ability. The present invention E is shown in FIG.
As shown in (1), the first inorganic material layer 57 that does not contain the powder of the frypontite mineral has the ability of the physical adsorption because it contains the acid-treated montmorillonite. Since the inorganic material layer 58 has no major pores other than vents having a size of 1000 Å or more, it has little physical adsorption capability. In the present invention F, as shown in FIG. 18, the acid-treated montmorillonite is applied to both the first inorganic material layer 59 not containing the powder of the fly ponite mineral and the second inorganic material layer 60 containing the powder of the fly ponite mineral. The pores of about 15 to 300 angstroms are formed, and both of the inorganic material layers have the physical adsorption ability.

As a result of examining the surface contamination prevention rate of each of these filters in the same manner as described above, the filters of the present invention were all excellent in adsorbing gaseous inorganic impurities of HCl and NH ₃ . However, for the gaseous organic impurities of DOP and pentameric siloxane (D5), the adsorption performance of the filter of the present invention A is particularly poor, and for the other filters BF of the present invention, the adsorption performance is excellent. Was. The reason that the present invention A is inferior in the performance of adsorbing gaseous organic impurities is that the inorganic material layer 51 has no major pores other than vents having a size of 1000 Å or more. There is little ability. Other filters have a physical adsorption of gaseous organic impurities of about 15-30.
Because pores of about 0 Å are formed,
Excellent adsorption performance was obtained.

The object to be treated by the filter of the present invention is not limited to air only. Even if an inert gas such as nitrogen or argon is treated, an inert gas suitable for the production of semiconductors and LCDs is also used. Needless to say, can be produced.

Next, 50 vol ppb of hydrogen chloride gas was applied to the two types of filters X and Y of the honeycomb structure according to the present invention.
And 80 ng / m ^{3 of} gaseous boron compound (weight concentration as boron atom B) were simultaneously passed through a clean room air, and the removal rate of each gas was examined. The filter X includes only a first inorganic material layer (adsorption first layer) in which powder of frypontite mineral is fixed on the surface of the honeycomb structure using inorganic powder as a binder. The filter Y is composed of a first inorganic material layer (adsorption first layer) in which frypontite mineral powder is fixed on the surface of the honeycomb structure using an inorganic powder as a binder, and silica gel on the first adsorption layer. The second inorganic material layer (adsorption second layer) is laminated. In each of these filters X and Y, the honeycomb structure is a ceramic fiber made of alumina and silicic acid. The filter X is prepared by impregnating the honeycomb structure with a suspension in which the powder of the flypontite mineral and the powder of the inorganic substance are dispersed, and then drying and impregnating the surface of the honeycomb structure with the first powder.
The layers were fixed. The filter Y impregnates the honeycomb structure with a suspension in which the powder of the fly pontitite mineral and the powder of the binder (inorganic substance) are dispersed, and then dries to form an adsorption first layer on the surface of the honeycomb structure. Further, the honeycomb structure support on which the first adsorption layer has been formed is impregnated with a suspension of silica gel powder, and then dried to dry the first adsorption layer.
A second adsorption layer was formed on the surface of the layer. These filters X,
Table 4 shows the structure of Y.

[0100]

[Table 4]

As shown in FIG. 19, hydrogen chloride gas 50 V
ol ppb and 80 ng / m ^{3 of} gaseous boron compound (weight concentration as boron atom B) at the same time, clean room (CR) air was led to a circuit 70 with a filter and a circuit 71 without a filter, respectively. The air passing through 70 and 71 was bubbled into ultrapure water in containers 72 and 73 to collect hydrogen chloride gas and gaseous boron compounds in the air. A filter 74 for removing particles made of polytetrafluoroethylene (trade name: Teflon), which does not cause generation of gaseous boron compounds, was installed in each of the circuits 70 and 71. The boron concentration in the ultrapure water after bubbling was determined by ICP-MS (Indu
Ctively Coupled Radio Fre
quency Plasma-Mass Spectr
measurement). Then, the removal efficiency of the hydrogen chloride gas and the gaseous boron compound removed in the circuit 70 is compared with the contents of the hydrogen chloride gas and the gaseous boron compound in the air flowing through the circuit 71 to determine the removal efficiency. Was.

Using the filters X and Y described above as the filters in the circuit 70 shown in FIG. 19, the removal efficiencies of the hydrogen chloride gas and the gaseous boron compound were compared. In addition,
The honeycomb size, ventilation conditions, etc. are as follows. Honeycomb size: 7.5 mm × 7.5 mm × 50 mmt Air flow rate: 4.1 liter / min Surface wind speed: 1.2 m / s Bubbling time: 5 days

FIG. 20 shows the change over time in the removal efficiency of the hydrogen chloride gas and the gaseous boron compound for the filters X and Y. No significant difference is seen in the hydrogen chloride removal rates of the filters X and Y until all the metals (zinc or magnesium) contained in the frypontite mineral have completely reacted with hydrogen chloride and lost the ability to adsorb hydrogen chloride gas. . However, the filter Y is clearly superior to the filter X with respect to the change over time in the removal efficiency of the gaseous boron compound. This is because silica gel, which has a high affinity (adsorption rate) with the gaseous boron compound, is present in both the first and second adsorption layers in the filter Y. This is due to the large number. As described above, the filter Y in which silica having a high affinity (adsorption rate) for the gaseous boron compound exists in both the first adsorption layer and the second adsorption layer removes the gaseous boron compound for a relatively long time. I knew I could do it.

Next, the operation and effect of the advanced cleaning apparatus according to the embodiment of the present invention will be described with reference to examples.

[0105] destination of the air purifying filter 31 of the present invention of the honeycomb structure was fixed powder fly Pont tight minerals may collectively remove gaseous inorganic impurities not only gaseous organic impurities described in FIG. 8 5000 m ³ 21 is provided with an HCl concentration meter and an NH3 concentration meter in the advanced cleaning apparatus of FIG. 21 according to the embodiment of the present invention provided for processing circulating air at a rate of / min.
To measure the concentration of H ₃ per month. In addition, the silicon wafer substrate with the oxide film without organic contamination immediately after the cleaning was left in the advanced cleaning apparatus of FIG. 21, and the contact angles were measured immediately after the cleaning and after 12 hours, respectively. Called for an increase. The measurement of the increase in the contact angle due to standing for 12 hours (washing → measuring the contact angle → standing for 12 hours → measuring the contact angle) was similarly repeated every month. The contact angle on the surface of the silicon wafer with the oxide film immediately after the cleaning was 3 °. The amount of the powder of the frypontite mineral used as an adsorbent in the present invention, which was used for treating the circulating air at 5000 m ³ / min, was 500 kg. That is,
The amount of adsorbent used per 1 m ³ / min of air flow is 0.1
kg.

Next, the air purification filter 11 according to the present invention will be described.
1 is a conventional chemical filter in which fibrous activated carbon is combined with a binder made of low-melting polyester or polyester non-woven fabric to form a felt, or a sheet-shaped conventional filter in which granular activated carbon is bonded to a breathable urethane foam with an adhesive. Was replaced with a conventional chemical filter in which the ion-exchange fiber was combined with a binder made of low-melting polyester or non-woven polyester to form a felt shape. Air purification filter 1 according to the present invention
11 was replaced with three types of conventional chemical filters.
And the concentration of NH ₃ was measured every month. In addition, in each of the conventional advanced cleaning apparatuses, the silicon wafer substrate with an oxide film without organic contamination immediately after cleaning was left alone, and the contact angles were measured immediately after cleaning and after 12 hours, respectively.
The increase in the contact angle after leaving for 2 hours was determined. The measurement of the increase in the contact angle due to standing for 12 hours (washing → measuring the contact angle → standing for 12 hours → measuring the contact angle) was similarly repeated every month. The adsorption material in the conventional chemical filter used in each conventional example, ie, activated carbon fiber, granular activated carbon,
The amount of ion exchange fiber used is the same as in the above-described embodiment of the present invention.
It was 0.1 kg per 1 m ³ / min of air flow.

Furthermore, the air purification filter 1 according to the present invention
In the case where neither the chemical filter 11 nor the conventional chemical filter is provided, similarly, HCl and NH ₃ in the advanced cleaning device are used.
And the contact angle were measured.

As a result of the measurement of the concentration of HCl, the concentration of HCl in the advanced cleaning apparatus without the air purification filter 111 according to the present invention or the chemical filter according to the conventional configuration was in the range of 0.5 ppb to 0.9 ppb. . On the other hand, the HCl concentration in the advanced cleaning device provided with either the air purification filter 111 according to the present invention or the chemical filter according to the conventional configuration is 0.03 p.
It was in the range of pb to 0.05 ppb, and after one year, exceeded 0.05 ppb due to a decrease in adsorption performance.

[0109] As a result of the concentration measured in the NH _3, NH ₃ concentration in the advanced cleaning apparatus is not provided any of the chemical filter by the air purifying filter 111 and a conventional arrangement according to the invention was in the range of 10ppb from 5 ppb. On the other hand, the NH ₃ concentration in the advanced cleaning device provided with either the air purification filter 111 according to the present invention or the chemical filter having the conventional configuration is in the range of 0.5 ppb to 1.0 ppb for about one year after operation. After one year, it exceeded 1.0 ppb due to a decrease in adsorption performance.

The air purification filter 111 of the honeycomb structure to which the powder of the frypontite mineral according to the present invention is fixed.
, An advanced cleaning device atmosphere provided with a chemical filter having a conventional configuration, and an advanced cleaning device atmosphere provided with neither the air purification filter 111 according to the present invention nor the chemical filter having a conventional configuration. The change over time in the contact angle of the surface of the silicon wafer with the exposed oxide film was compared.

The contact angle of the surface of the silicon wafer with the oxide film exposed to the atmosphere of the high-purity cleaning apparatus provided with the air purification filter 111 according to the present invention changed to 4 ° after being left for 12 hours. Since the contact angle on the surface of the silicon wafer with the oxide film immediately after the cleaning was 3 °, it was increased by 1 °.

On the other hand, the contact angle of the surface of the silicon wafer with the oxide film exposed to the atmosphere of the advanced cleaning device provided with the chemical filter of the conventional configuration was 10
° increased. In other words, the conventional chemical filter that removes gaseous inorganic impurities has not only the ability to remove gaseous organic impurities, but also the filter media (eg, nonwoven fabric, binder, etc.) contained in the chemical filter and the activated carbon attached to the sheet. Adhesives (for example, neoprene resin, urethane resin, epoxy resin, silicon resin, etc.) and sealing materials (for example, neoprene rubber, silicon rubber, etc.) used to fix the filter medium to the surrounding frame The gaseous organic impurities generated from the wafer were included in the air after passing through the chemical filter, resulting in an increase in the contact angle corresponding to 10 ° on the wafer surface left for 12 hours. In the air purification filter 111 of the present invention, not only gaseous inorganic impurities but also gaseous organic impurities can be removed at a time, and as described briefly above, an example of the production method does not contain organic matter in the constituent material. The constituent materials themselves do not generate gaseous organic impurities. Therefore, the increase was only 1 ° on the wafer surface left for 12 hours.

Further, the contact angle of the surface of the silicon wafer with the oxide film exposed to the atmosphere of the high-purity cleaning apparatus without any of the air purification filter according to the present invention and the chemical filter according to the conventional configuration is 7 when left for 12 hours. °. That is, it increased by 4 °. The magnitude of this increase in contact angle is due to the fact that gaseous organic matter is not removed.

To summarize the above, the air purification filter according to the present invention and the chemical filter according to the conventional configuration have H
Although there is not much difference in the adsorption life and adsorption performance for Cl and NH _{3, the} air purification filter according to the present invention can collectively remove not only gaseous inorganic impurities but also gaseous organic impurities, and does not itself become a new organic substance contamination source. . Especially,
A filter in which silica or the like having a high affinity (adsorption rate) for the gaseous boron compound exists in both the first adsorption layer and the second adsorption layer can remove the gaseous boron compound for a relatively long time. On the other hand, the conventional chemical filter has the drawback that it can remove gaseous inorganic impurities but cannot remove gaseous organic impurities, and it itself becomes a new organic substance contamination source. In addition, the air purification filter according to the present invention is incombustible, whereas the conventional chemical filter is inflammable.

Next, a filter for removing particulate impurities composed only of a material that does not generate gaseous organic impurities is provided downstream of the air purification filter 111 of the advanced cleaning apparatus shown in FIG. 21 according to the embodiment of the present invention. A comparison was made between the case where the filter was attached and the case where a filter for removing a conventional particulate impurity that generates gaseous organic matter from the filter constituent material was attached. A silicon wafer substrate with an oxide film free from organic contamination immediately after cleaning was left in an advanced cleaning apparatus. Then, the contact angles immediately after the washing and after the standing for 12 hours were measured, and the increase in the contact angle after the standing for 12 hours was determined. When a filter for removing particulate impurities composed only of a material that does not generate gaseous organic impurities was attached, the contact angle on the wafer surface after standing for 12 hours increased by 1 °. The increase in the contact angle is extremely small for the following reasons. As described above, in the air purification filter of the present invention, gaseous organic impurities causing surface contamination are removed, and the filter itself does not become a new organic substance contamination source. In addition, the filter disposed downstream of the filter for removing particulate impurities does not generate gaseous organic impurities. On the other hand, when a conventional filter that removes particulate impurities that generate gaseous organic matter from the filter component is installed, the contact angle of the wafer surface after standing for 12 hours due to the degassing from the filter component is reduced. It has increased by 3 °. Of the increase of 3 °, the increase of 1 ° is due to gaseous organic matter that could not be completely removed by the air purification filter 111, but the remaining 2 ° is due to degassing from components of the filter for removing particles.

Although the preferred embodiment of the present invention has been described above with reference to an advanced cleaning apparatus (so-called clean room) for the whole semiconductor or LCD manufacturing process, the present invention is not limited to this embodiment. High-level cleaning equipment of various scales, such as a local high-level cleaning device called a mini-environment, a clean bench, a clean chamber, and various stockers for storing clean products, a processable air volume of the air purification filter, a circulating air volume and outside air intake Various embodiments can be considered according to the processing environment such as the ratio of the amount of air and the presence or absence of gaseous impurities from inside the advanced cleaning device.

For example, using a 300 mm diameter silicon wafer, a 256 Mbit DRAM or a 1 Gbit DRAM
Semiconductor production is about to start around 1999.
In such a semiconductor manufacturing apparatus, an inert gas such as nitrogen or argon is supplied from an inert gas supply device until the reaction process is started after a wafer is introduced into the chamber in the apparatus and the wafer is introduced into the chamber. To fill. This inert gas has an extremely high purity specification, and the inert gas itself does not cause surface contamination of the wafer. However, in order to turn on and off the supply of the inert gas, a valve is provided between the inert gas supply device and the chamber, and various chemical contaminants causing wafer surface contamination are generated from the constituent material of the valve. . By providing the air purifying filter according to the present invention in the gas flow path between the valve and the chamber, the air purifying filter removes various chemical contaminants generated from the valve without generating gaseous contaminants from itself. This has helped to prevent wafer surface contamination and improve quality.

[0118]

According to the present invention, the following effects can be obtained. Manufacturing of semiconductors and LCDs by adsorbing and removing both gaseous inorganic impurities and gaseous organic impurities, which cause substrate surface contamination in the atmosphere, to prevent contamination of substrate surfaces handled by advanced cleaning equipment. Thus, clean air from which gaseous impurities that cause contamination of the substrate surface are removed can be produced. Further, in the manufacture of semiconductors and LCDs, contamination of the substrate surface could be prevented by using the clean air thus produced as an atmosphere of an advanced cleaning device to which the substrate surface was exposed.

Further, powder of frypontite mineral is used as an adsorbent for adsorbing and removing gaseous inorganic impurities, and various inorganic powders are appropriately selected as an adsorbent for adsorbing and removing gaseous organic impurities. By combining them, it is possible to provide an air purification filter that does not contain flammable substances in the constituent materials, and the advanced cleaning device constructed using this air purification filter can be used for conventional activated carbon adsorbents and ion exchange fibers. It was superior in disaster prevention compared to advanced cleaning equipment built using an air purification filter. It is possible to provide an air purification filter composed only of a material that does not generate gaseous organic substances that cause substrate surface contamination,
The advanced cleaning equipment constructed using this air purification filter completely eliminates organic contamination on the substrate surface compared to the advanced cleaning equipment constructed using conventional activated carbon adsorbents and air purification filters made of ion exchange fibers. Could be prevented.

The main impurities to be removed by the air purification filter of the present invention are gaseous inorganic impurities such as acidic substances, basic substances, and dopants. There is also an effect on the removal of water. Conventionally, four types of dedicated chemical filters had to be prepared according to the respective impurities of acidic, basic, dopant, and organic substances. However, in the air purification filter of the present invention, both acidic and basic inorganic impurities were used. Not only collectively, but also organic impurities can be collectively removed, so that the advantages such as a reduction in the volume of the adsorption layer, a reduction in pressure loss, and a reduction in the production cost of the adsorption layer are further enhanced. In particular, an air purification filter in which an inorganic substance such as silica having a high affinity (adsorption rate) with a gaseous boron compound is present in both the first inorganic material layer and the second inorganic material layer, is a sum of inorganic substances such as silica. The amount of the gaseous boron compound is small, the removal efficiency of the gaseous boron compound is small with time, and the gaseous boron compound can be removed for a relatively long time.

[Brief description of the drawings]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory view of a frypontite mineral having a double-structured crystal in which one side is solid basic and the other side is solid acidic.

FIG. 2 is an enlarged view of an inorganic material layer showing a state in which unit layers or at most several layers of frypontite having a two-layer structure are dispersed in space one by one without overlapping each other. FIG.

FIG. 3 is a schematic exploded view of the filter according to the embodiment of the present invention.

FIG. 4 is a partially enlarged cross-sectional view of a filter in which an inorganic material layer is formed by fixing powder of frypontite mineral to the surface of a honeycomb structure using an inorganic binder.

FIG. 5 is a partially enlarged cross-sectional view of a filter having a configuration in which pellets obtained by granulating powder of frypontite mineral using an inorganic binder are fixed to the surface of a honeycomb structure.

FIG. 6 is a partially enlarged view of an inorganic material layer cross section showing an inorganic material layer in which a powder of frypontite mineral according to the present invention is supported on the surface of a support with an inorganic binder.

FIGS. 7A and 7B are a cross-sectional view and a vertical cross-sectional view of an air purification filter in which pellets of frypontite mineral powder are filled in a double cylindrical casing.

FIG. 8 is a schematic exploded view of a filter according to another embodiment of the present invention.

FIG. 9 shows a first inorganic material layer formed by adhering flypontite mineral powder using an inorganic binder to the surface of a honeycomb structure in which a corrugated sheet and a thin sheet are laminated, and furthermore, inorganic adsorption on the surface. FIG. 4 is a partially enlarged cross-sectional view of a filter having a configuration in which a powder is fixed to form a second inorganic material layer.

FIG. 10 is a partially enlarged view of a cross section of a composite layer including a first inorganic material layer and a second inorganic material layer in the present invention.

FIG. 11 shows a silicon wafer with an oxide film in a total of four atmospheres of clean room air treated by two types of commercially available chemical filters and a chemical filter using ion exchange fibers, and clean room air treated by the filter according to the present invention. 4 is a graph showing the results of measuring the change over time in the contact angle of the surface.

FIG. 12 shows a measured value of a contact angle obtained by dropping ultrapure water and an X-ray photoelectron spectroscopy (XPS: X-ray Photo) on a glass substrate surface left in a clean room atmosphere.
5 is a graph showing a correlation between organic substance surface contaminations measured by electron spectroscopy (Oletron Spectroscopy).

FIG. 13 is a structural sectional view of an inorganic material layer of the present invention A.

FIG. 14 is a structural sectional view of an inorganic material layer of the present invention B.

FIG. 15 is a schematic perspective view and a structural cross-sectional view of the first and second inorganic material layers of the present invention C.

FIG. 16 is a structural sectional view of the first and second inorganic material layers according to Invention D.

FIG. 17 is a structural sectional view of the first and second inorganic material layers of the present invention E.

FIG. 18 is a structural sectional view of the first and second inorganic material layers of the present invention F.

FIG. 19 is an explanatory diagram of a circuit for examining the removal efficiency of a hydrogen chloride gas and a gaseous boron compound.

FIG. 20 is a graph comparing the removal efficiencies of hydrogen chloride gas and gaseous boron compounds of filters X and Y.

FIG. 21 is an explanatory diagram schematically showing a configuration of an advanced cleaning device according to an embodiment of the present invention.

FIG. 22 is an explanatory view schematically showing a configuration of an advanced cleaning apparatus according to another embodiment of the present invention.

[Explanation of symbols]

 Reference Signs List 1 filter 12 support 25 first inorganic material layer 26 second inorganic material layer 100 advanced cleaning device

Claims (15)

[Claims] 1. An air purification filter wherein an inorganic material layer is formed by fixing a powder of frypontite mineral to a surface of a support using an inorganic powder as a binder. 2. The method of claim 1, wherein the powder of the frypontite mineral is talc, kaolin mineral, bentonite, diatomaceous earth, silica, alumina, a mixture of silica and alumina, aluminum silicate, activated alumina, porous glass, and hydrated silica having a ribbon-like structure. An air purifying filter, wherein an inorganic material layer is formed by fixing an inorganic powder comprising at least one of magnesium clay mineral, activated clay and activated bentonite to a surface of a support as a binder. 3. A first inorganic material layer in which frypontite mineral powder is fixed using inorganic powder as a binder,
Diatomaceous earth, silica, alumina, mixture of silica and alumina, aluminum silicate, activated alumina, porous glass, hydrated magnesium silicate clay mineral with ribbon-like structure,
A second inorganic material layer made of at least one of activated clay and activated bentonite is laminated so that one of the first inorganic material layer and the second inorganic material layer is in contact with the surface of the support. An air purification filter, characterized in that: 4. A powder of a frypontite mineral, talc, kaolin mineral, bentonite, diatomaceous earth, silica, alumina, a mixture of silica and alumina, aluminum silicate, activated alumina, porous glass, and hydrated silica having a ribbon-like structure. An air purification filter characterized in that pellets obtained by granulating a powder of an inorganic substance comprising at least one of a magnesium clay mineral, activated clay and activated bentonite as a binder are fixed to the surface of a support. 5. A method in which frypontite mineral powder is granulated around a first pellet formed by using an inorganic powder as a binder, diatomaceous earth, silica, alumina, a mixture of silica and alumina, aluminum silicate, activated alumina. A second pellet coated with an inorganic powder comprising at least one of porous glass, hydrated magnesium silicate clay mineral having a ribbon-like structure, activated clay, and activated bentonite is fixed to the surface of the support. And an air purification filter. 6. The air purification filter according to claim 1, wherein the support is a honeycomb structure. 7. The air purification filter according to claim 6, wherein the honeycomb structure is a structure containing inorganic fibers as an essential component. 8. Talc, kaolin mineral, bentonite,
Diatomaceous earth, silica, alumina, mixture of silica and alumina, aluminum silicate, activated alumina, porous glass, hydrated magnesium silicate clay mineral with ribbon-like structure,
Pellet obtained by granulating the powder of the flypontite mineral using an inorganic powder composed of at least one of activated clay and activated bentonite, or granulating the powder of the flypontite mineral using the inorganic powder as a binder. Diatomaceous earth, silica, alumina, a mixture of silica and alumina, aluminum silicate,
A second pellet coated with an inorganic powder comprising at least one of activated alumina, porous glass, hydrated magnesium silicate clay mineral having a ribbon-like structure, activated clay, and activated bentonite is filled in a casing. Air purification filter. 9. The inorganic substance, wherein the total volume of pores distributed in a range of 15 to 300 Å is 0.2 cc / g or more per weight, or the specific surface area of the pores is 100 m ² / g or more. The air purification filter according to any one of claims 1, 2, 3, 4, 5, 6, 7, and 8. 10. The inorganic material layer, the first inorganic material layer,
The second inorganic material layer, the pellet, the first pellet and the second
The inorganic fixing aid is mixed in at least one of the pellets of the above (1), (2), (3), (4) and (4).
The air purification filter according to any one of 5, 6, 7, 8 and 9. 11. The method according to claim 1, wherein the inorganic fixing aid is sodium silicate,
The air purification filter according to claim 10, comprising at least one of silica and alumina. 12. A powder of frypontite mineral, talc, kaolin mineral, bentonite, diatomaceous earth, silica, alumina, a mixture of silica and alumina, aluminum silicate, activated alumina, porous glass, and hydrated silica having a ribbon-like structure. After the support is impregnated with a suspension in which at least one inorganic powder of a magnesium clay mineral, activated clay, and activated bentonite is dispersed, the support is dried to form an inorganic material layer on the surface of the support. A method for manufacturing an air purification filter, characterized by fixing. 13. A support in which a suspension of a powder of frypontite mineral and a powder of an inorganic substance as a binder is impregnated with a support, and the support is dried to form a first surface on the surface of the support. A support on which an inorganic material layer is formed, and on which the first inorganic material layer is formed, is composed of diatomaceous earth, silica, alumina,
Impregnated in a suspension of at least one inorganic powder of a mixture of silica and alumina, aluminum silicate, activated alumina, porous glass, hydrated magnesium silicate clay mineral with a ribbon-like structure, activated clay, and activated bentonite. After drying, the second inorganic material layer is formed on the surface of the first inorganic material layer, or the second inorganic material layer is formed on the surface of the support, and then the second inorganic material layer is further formed. A method for manufacturing an air purification filter, comprising forming the first inorganic material layer on a surface of the inorganic material layer. 14. An advanced cleaning apparatus having a circulation path for circulating air in a space where a clean atmosphere is required,
Claims 1, 2, 3, 4, 5, 6, 7,
The air purifying filter according to any one of 8, 9, 10 and 11, and a filter for removing particulate impurities is disposed upstream of the space and downstream of the air purifying filter. Advanced cleaning equipment. 15. The advanced cleaning apparatus according to claim 14, wherein the air purification filter and the filter for removing particulate impurities are arranged on a ceiling of the space.