JP3415730B2 - Gaseous impurity treatment system and particle removal filter - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor device (LS)
The present invention relates to a technique for removing gaseous impurities contained in an atmosphere of a clean room for manufacturing I) and a liquid crystal display (LCD).

[0002]

2. Description of the Related Art A so-called HEPA filter (High Efficiency) is one of manufacturing techniques for improving the yield and reliability in LSI and LCD manufacturing processes.
Particulate Air Filter) or U
LPA filter (UltraLow Penetrat)
There is a filter for removing fine particles called an ion air filter. These filter technologies have greatly contributed to clean manufacturing processes. The nominal trapped particle size guaranteed by the HEPA filter is currently 0.0
Although it is 5 μm, practically, almost all fine particles of nanometer (thousandths of μm) size can be removed. That is, the filter for removing fine particles may be said to be an already completed technology.

A highly integrated semiconductor device which has recently entered mass production has a fine structure with a wiring size of 0.5 μm and a gate oxide film thickness of 10 nm, as typified by a 16M-DRAM. In the manufacturing process of such a highly integrated semiconductor device, the fine particles are of course a problem as a contamination source that causes a product defect. However, the HEPA filter and U
There are almost no particulates that can be a source of contamination in the air that passes through the LPA filter and is supplied to the clean room. Therefore, it is considered that the fine particles existing in the clean room are generated by dust generation from a robot, an operator, or a manufacturing device inside the clean room.

In the process of manufacturing a highly integrated semiconductor device having a wiring size of submicron or less, gaseous impurities smaller than fine particles adhere to a clean surface of a product.
Needs of electrical characteristics of device, selectivity of dry etching and C
It is beginning to affect the adhesiveness of the multilayer film of VD. The gaseous impurities are atomic / molecular or ionic substances having a size of about Å to nm (1 nm = 10 Å) which cannot be removed by the HEPA filter.
It is known that the properties of gaseous impurity contamination are more active in physical phenomena such as adsorption / desorption, interface phenomena, and chemical reaction phenomena, as compared with particle contamination. The following is a list of gaseous impurities known to be present in the atmosphere of the clean room and their causes.

(1) Gaseous impurities F ⁻ , Cl ^−, SO ₄ ²⁻ , NO ₂ ⁻ , NO ₃ ⁻ , PO ₄ ³⁻ , and organic solvents leaked from manufacturing equipment, exhaust systems, etc. gaseous impurities NOx derived from ambient air ^-, SOx ^2-, Cl ^-, organic, etc. (3) gaseous impurities NH ₄ derived from such an operator ^{+, Cl -, Na +,} K +, organic matter, etc. (4) cassette Osamu volatile impurities F from such ingredients and wafer receiving member ^-, organics, etc. (5) structures and devices volatile impurities boron compounds from the material of the organic phosphorus compound such as

A so-called chemical filter is known as an apparatus for removing such gaseous impurities. Most chemical filters are based on activated carbon, and organic gases can be removed by physical adsorption as it is. On the other hand, an acid-based gas, an alkali-based gas, and a sulfur-based gas can be removed by chemical adsorption by a neutralization reaction by adding various impregnating substances to the activated carbon surface.

[0007] These chemical filters are used in a form attached to the upstream (upstream side) of a high-performance filter usually called a medium-performance air filter, HEPA or ULPA. The reason for this is that activated carbon is used as the adsorbing filter medium of the chemical filter, and the activated carbon itself generates crushed particulate contaminants. However, when gaseous impurities having a low concentration on the order of ppb are considered, a filter material (for example, a nonwoven fabric or a binder) of a medium-performance air filter or a high-performance filter itself, or a sealing material used for fixing the filter material (for example, Gaseous impurities that desorb from neoprene rubber, silicone rubber, etc. or adhesives (eg, neoprene resin, urethane resin, epoxy resin, silicon resin, etc.) float in the clean room and adversely affect devices. there is a possibility. In this specification, the medium performance air filter is simply referred to as a medium performance filter, and the HEPA or ULPA filter is referred to as a high performance filter.

There is also known an apparatus for removing gaseous impurities using a catalytic catalytic combustion method. This gaseous impurity removal device uses a so-called contact catalytic method that brings heated process air into contact with a noble metal catalyst such as platinum or palladium or an oxide catalyst such as copper, manganese, chromium, nickel, or iron. It decomposes gaseous organic impurities contained into carbon dioxide and water that are harmless to products. However, even in such an apparatus, there is a possibility that fine particles may be generated from the catalyst inside the catalytic combustion cylinder, and it is essential to attach a high-performance filter on the downstream side. Also, in this case, as in the case of the chemical filter, if a material that generates gaseous impurities is used for the components of the high-performance filter on the downstream side of the gaseous impurity removal device, the desorbed gaseous impurities may be used. Can float in the clean room and adversely affect the device.

[0009] Further, an apparatus for removing gaseous impurities using a fluidized bed adsorption tower is also known. This fluidized bed adsorption tower,
A fluidized bed made of an adsorption filter medium such as granular activated carbon is formed on a multi-layered perforated plate, and the fluidized bed is configured to be successively dropped to a lower stage while flowing and moving in each stage. During this time, the treated air is made to flow upward, and is brought into uniform contact with the fluidized bed of the adsorption filter medium at each stage to adsorb gaseous impurities in the treated air. The purified air is discharged from the upper part of the adsorption tower. In addition, the adsorption filter medium that has reached the bottom of the adsorption tower is returned to the uppermost stage of the adsorption tower by the airflow carrier, and falls again. In such a fluidized adsorption tower, the adsorbed filter media in a fluidized state generate numerous micron-sized fine particles by rubbing each other. Such fine particles are HEP
Attempts to remove with a high performance filter called A or ULPA will cause clogging in a short period of time. Therefore, first, micron-sized filter medium wear particles are removed by a medium-performance filter, and a small amount of submicron-sized particles that cannot be removed by the medium-performance filter are removed by a high-performance filter provided further downstream. Therefore, also in this case,
If the material that generates gaseous impurities as described above is used for the components of the medium-performance filter or high-performance filter downstream of the gaseous impurity removal device, the desorbed gas floats in the clean room, Devices can be adversely affected.

[0010]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the conventional apparatus for removing gaseous impurities, and the filter itself causes gaseous impurity contamination. It is an object of the present invention to provide a new and improved apparatus for removing gaseous impurities in a clean room atmosphere, which can prevent the occurrence of air pollution and extend the life of the filter.

[0011]

According to a first aspect of the present invention, a gaseous impurity treatment for removing gaseous impurities contained in a gas phase to generate clean air is provided. A system is provided. Then, the gaseous impurity treatment system removes gaseous impurities contained in the untreated air, but itself generates gaseous impurities in the treated air, and the gaseous impurity removal means. High-performance filter consisting only of materials that do not generate gaseous impurities, located downstream of the removal means , or medium-performance
It comprises a filter and a filter means comprising a high-performance filter .

As the gaseous impurity removing means, gaseous organic impurities such as an adsorption filter medium, a fluidized bed adsorption tower, or a catalytic catalytic combustion tube capable of removing gaseous impurities contained in a gas phase with high performance can be used. Products that decompose into carbon dioxide and water that are harmless to products can be used. Any of the gaseous impurity removing means generates particulate impurities from the adsorbent or the catalyst. Therefore, a filter means for removing particulate impurities composed only of a material that does not generate gaseous impurities must be provided downstream of them.

[0013] In addition, on the downstream side of the gaseous impurity removing means,
Backup filter means for removing particulate impurities composed only of a material which does not generate gaseous impurities may be connected to the filter means in parallel and selectively switchable. According to such a configuration, when replacing the clogged filter means, the operation of the system does not need to be interrupted by switching the air path to the backup filter means.

As a filter means which is disposed downstream of the gaseous impurity removing means and which does not generate gaseous impurities, for example, fine particles having a particle diameter of 0.3 μm called a HEPA filter or an ULPA filter are 99.97. % High performance filter can be used.
In addition, a medium-performance filter, which is also called a medium-performance air filter and can collect fine particles having a particle diameter of 0.3 μm or 0.3 μm or more at less than 99.97%, is disposed upstream of the high-performance filter. You may. The medium-performance filter may be provided with a filter regenerating means for removing and regenerating the captured fine particles, for example, a filter for removing the captured fine particles by mechanical vibration or a backwash gas stream.
The filter means composed only of a material that does not generate gaseous impurities (for example, metal, ceramics, glass fiber, etc.) is, for example, composed of only a metal frame element and a glass fiber filter element, or a metal frame element and a metal fiber element. It can be constituted only by the filter element made of the material. When the filter means is attached, it is preferable to use an inorganic material packing or a fluororesin packing which does not generate gaseous impurities. Also, even if it is an organic resin,
Any substance can be used as long as it has been subjected to a heat treatment to remove volatile components and to be treated so as to prevent degassing relating to surface contamination.

[0015]

[0016]

BRIEF DESCRIPTION OF THE DRAWINGS FIG.
A preferred embodiment of a gaseous impurity treatment system and a particle removal filter mounted on the system according to the present invention will be described in detail.

FIG. 1 shows a first embodiment of a gaseous impurity treatment system according to the present invention. As shown, the system 100 includes a casing 102,
On the upstream side, as a gaseous impurity adsorption filter medium 110,
Three types of chemical filters based on activated carbon fiber, namely, a filter 112 for treating an acidic gas, a filter 114 for treating an alkaline gas, and a filter 11 for treating an organic gas.
6 are stacked in three layers, and a high-performance filter 120 is attached on the downstream side. In the drawing, reference numeral 104 denotes a fan module having a built-in blower, which is mounted on the upstream side of the casing 102, and which has an adsorbing filter medium 110 and a high-performance filter
It plays the role of blowing untreated air to zero. As described later, the high-performance filter 120 is composed of only a frame element and a filter element made of one or both of metal and ceramics, and is made of a material that does not generate gaseous impurities from itself. Or a material containing a volatile component such as an organic resin, which has been subjected to heat treatment or the like to prevent degassing. Although only the high-performance filter 120 is installed in the illustrated example, a medium-performance filter may be installed on the upstream side. Also, as described below,
A regeneration device may be provided in the medium performance filter to extend the replacement life of the filter. When attaching the high-performance filter 120 to the casing 102, it is preferable to use a seal member that does not generate an organic substance gas, for example, an inorganic material packing or a fluororesin packing such as Teflon. In addition, even if an organic resin is obtained by removing volatile components by heat treatment, it can be used because it does not generate gaseous impurities related to surface contamination.

As described above, the adsorbing filter material 110 of the chemical filter installed on the upstream side of the system is used.
Is based on activated carbon, which itself can be a source of pollutants that generate crushed particulate contaminants. That is,
The adsorption filter medium 110 removes gaseous impurities contained in the untreated air, but can itself be a source of particulate impurities. Therefore, a filter means for removing particulate impurities is required on the downstream side. Conventional HEPA filter or U
In a high-performance LPA filter, gaseous impurities are generated from a filter medium, a sealing material, an adhesive, and the like that constitute the filter itself. The treated air from which the gaseous impurities have been removed is contaminated again by the gaseous impurities, even if the particulate impurities can be completely removed when passing through these filters. However, according to an embodiment of the present invention,
Since the high-performance filter 120 that does not generate gaseous impurities is provided downstream of the adsorption filter medium 110, clean air containing no gaseous impurities can be supplied.

FIG. 2 shows a second embodiment of the gaseous impurity treatment system according to the present invention. This gaseous impurity treatment system 100 ′ uses a catalytic catalytic combustion cylinder 130 as a gaseous impurity treatment device installed upstream of the system, and generates gaseous impurities configured according to the present invention downstream thereof. High performance filter 12
0 'is set. This contact catalytic combustion cylinder 130
Is mainly composed of a compressor 132 for compressing the introduced air, a reaction tower 134 for heating the air to react with the catalyst, and a heat exchanger 136 for cooling the processed air. Further, the catalytic catalytic combustion cylinder 130 is provided between the compressor 132 and the reaction tower 134 in the air supply path.
38, a pressure gauge 140 and a flow meter 142 are interposed,
It is possible to adjust the cleanliness, pressure, and flow rate of the generated clean air, respectively. In the reaction tower 134,
For example, an oxidation catalyst such as platinum or palladium is placed, and the hydrocarbons contained in the air can be burned and decomposed by the heater 144 as shown by the following formula. In the figure, reference numeral 146 denotes a temperature instruction adjusting alarm for preventing the reaction tower 134 from overheating. 2CnHm + (m / 2 + 2n) O ₂ → 2nCO ₂ + m
H ₂ O

In this manner, the clean air or the outside air in the clean room is, for example, 420
The gas is sent to the reaction tower 134 heated to
Reacts with the oxidation catalyst inside, and hydrocarbons are decomposed into water and carbon dioxide gas and removed. Even in such a device, there is a possibility that fine particles are generated from the catalyst inside the catalytic catalytic combustion tube 130. However, according to the present embodiment, since the high-performance filter 120 'that does not generate gaseous impurities is installed downstream of the catalytic catalytic combustion tube 130, clean air that does not contain gaseous impurities can be supplied. . The details of the high-performance filter 120 'will be described later. Although only the high-performance filter 120 'is installed in the illustrated example, a medium-performance filter may be installed upstream of the high-performance filter 120'. Further, as described later, a regeneration device may be provided in the medium-performance filter to extend the replacement life of the filter. When attaching the high performance filter 120 'to the system,
It is preferable to use a seal member that does not generate an organic substance gas, for example, an inorganic material packing or a fluororesin packing such as Teflon. Also, in the case of the present embodiment, FIG.
As will be described later with reference to FIG. 5 and FIG. 5, a backup filter for the high performance filter 120 ′ may be connected in parallel so that the air path is switched when the high performance filter 120 ′ is replaced.

FIG. 3 shows a third embodiment of the gaseous impurity treatment system according to the present invention. This gaseous impurity treatment system 100 ″ uses a fluidized bed adsorption tower 150 as a gaseous impurity treatment device installed on the upstream side of the system, and generates gaseous impurities configured according to the present invention on the downstream side thereof. A medium-performance filter 122 and a high-performance filter 124 are sequentially provided in series from the upstream side, and a regeneration device may be provided in the medium-performance filter 122 to extend the replacement life of the filter, as described later. When attaching the medium-performance filter 122 or the high-performance filter 124 to the system, it is preferable to use a seal member that does not generate an organic substance gas, for example, a fluorine resin packing such as an inorganic packing or Teflon. Even for resin, heat treatment removes volatile substances and eliminates the generation of gaseous impurities related to surface contamination. It can be used as long as the material.

The fluidized bed adsorption tower 150 is roughly divided into a fluidized bed adsorption section 152, a seal section 154, and an adsorption filter medium transport section 156. The fluidized bed adsorption section 152 includes an adsorption tower 158.
A multi-layered perforated plate 160 is provided therein. The adsorption filter medium (for example, granular activated carbon) is supplied to the fluidized bed adsorption section 15.
2, the fluidized bed 16 having, for example, a stationary bed height of 10 to 20 mm and a fluidized bed height of 20 to 40 mm on the multi-stage perforated plate 160
2 and flow down in each stage while moving and moving in each stage.
From 60a, it sequentially falls down. During this time, the adsorbed filter medium is supplied from the air inlet 163 through the damper 163b and the vortex blower 163a, and the processing air 1 flowing upward.
64 and uniformly adsorbs impurity gas components in the processing air. On the other hand, the purified air 166 is discharged from the upper portion 158a of the adsorption tower 158. In addition, the adsorption filter medium that has reached the adsorption tower bottom 158b forming the seal section 154 is returned to the uppermost stage of the adsorption tower by the adsorption filter medium transport section 156, and moves to the adsorption step again.

The apparatus for removing gaseous impurities using such a fluidized bed adsorption tower 150 has an advantage that the air to be treated passes through the bed of the adsorbing filter medium in a fluidized state, so that the ventilation resistance is extremely low. For example, when the air to be treated at 1 m / s passes through a fluidized bed having a height of 1.5 cm, which is a stationary bed made of granular activated carbon having a diameter of 0.7 mm, the airflow resistance is only 10 mmH _2.
O. In order to reduce the concentration of gaseous organic impurities on the order of ppm contained in the air to be treated to 1 ppb or less, it is sufficient to allow at least seven stages of fluidized beds, that is, a ventilation resistance of 70 mmH ₂ O. During long-term continuous operation, the adsorption filter medium in the adsorption tower adsorbs impurities and approaches breakthrough (a state in which the adsorption performance is lost due to saturation). Therefore, it is necessary to replace the adsorption filter medium as soon as possible in anticipation of safety before the breakthrough. For example, if the life until the breakthrough is two years, it can be replaced every six months.

A description will now be given of the adsorbing filter medium conveying section 156 shown in FIG. The adsorption filter medium transport unit 156 is provided with the turbo blower 16.
The compressed air 178 is sent to the uppermost stage of the adsorption tower by the turbo blower 168 via the damper 174, the three-way pipe 172, and the airflow transport pipe 176. Three-way pipe 17
In 2, the compressed air 178 and the adsorbing filter medium coming out of the outlet 170 are mixed. There are two systems for taking out the adsorbing filter medium from the outlet 170, a first path 170a and a second path 170b. The adsorbing filter medium taken out of the first path 170a is transported by compressed air 178 to the uppermost stage of the adsorption tower. Is done. At this time, the second path 170b is closed by closing the damper 174a and the valve 180.

On the other hand, when replacing the adsorption filter medium, the spiral blower 163a is stopped, the damper 174 is closed, and the first path 170a is closed. Conversely, the second path 170b opens,
In the three-way pipe 172a, the compressed air 178a that has passed through the damper 174a and the adsorption filter medium that has come out of the outlet 170 are mixed. This adsorbed filter medium is transported by air to the used filter medium storage tank 182 via the valve 180. The compressed air 178a used for the airflow is discharged to the outside from an exhaust port 182a attached to the storage tank 182.

All used filter media of the adsorption tower 158 are stored in the storage tank 1
After the air stream is conveyed to the storage tank 82, the valve 1
Open 82b and take out the used filter medium to the outside. on the other hand,
The unused adsorption filter medium is put into the unused filter medium storage tank 184 from the supply port 184a. After that, the unused adsorption filter medium is
The gas enters the adsorption tower 158 from the intake port 188 via 86.

In the fluidized bed adsorption tower 150, the adsorbing filter medium in a fluidized state itself is a source of fine particles. However, according to the present embodiment, the fluidized bed adsorption tower 15
0, a medium-performance filter 122 and a high-performance filter 124 that do not generate gaseous impurities are installed.
It is possible to supply clean air containing neither gaseous impurities nor particulate impurities. The details of the medium performance filter 122 and the high performance filter 124 will be described later. In the illustrated example, the medium-performance filter 122 and the high-performance filter 124 are arranged in series, but a configuration in which only the high-performance filter 124 is provided may be adopted. However, in such a fluidized bed adsorption tower 150, the adsorbing filter media in a fluidized state generate numerous micron-sized fine particles by rubbing against each other.
Or a high-performance filter called ULPA, for example, a dust concentration of 1 mg / m ³ and a ventilation air velocity of 0.3
In the case of m / sec, clogging occurs completely in about two months. Therefore, as shown in the present embodiment, first, micron-sized filter medium wear particles are removed by the medium-performance filter 122, and slight submicron-size particles that cannot be removed by the medium-performance filter 122 are further provided on the downstream side. It is preferable to adopt a configuration in which the filter is removed by the high-performance filter 124. Furthermore, as described later, a regeneration device may be provided in the medium-performance filter 122 to extend the replacement life of the filter. When attaching the medium-performance filter 122 or the high-performance filter 124 to the system, it is preferable to use a seal member that does not generate an organic substance gas, for example, a fluorine resin packing such as an inorganic packing or Teflon. When an organic resin is used, it is necessary to remove volatile components by heat treatment to eliminate gaseous impurities involved in surface contamination.

When the medium-performance filter 122 and the high-performance filter 124 that do not generate gaseous impurities are installed on the downstream side of the fluidized bed adsorption tower 150, the medium-performance filter 122 is clogged with fine particles generated from the adsorption filter medium. What has happened has already been mentioned. Such a clogged filter must be replaced with a new filter. During the replacement operation, the operation of the gaseous impurity removing system according to the embodiment of the present invention shown in FIG. 3 must be stopped. . The gaseous impurity removal system according to the embodiment of the present invention relates to a technology for removing gaseous impurities contained in an atmosphere of a clean room for manufacturing an LSI or an LCD, and for example, fills a storage atmosphere of an LSI or an LCD substrate. It is used to supply clean air containing neither gaseous impurities nor particulate impurities.
Usually, LSI and LCD substrates are manufactured in a clean room 24 hours a day, seven days a week, so it is desirable that the operation of this system should not be stopped even during the filter replacement work. Therefore, it is desirable to provide a separate filter serving as a backup as shown in FIGS. 4 and 5 on the downstream side of the fluidized bed adsorption tower 150 from the beginning.

As a backup filter of another system, a filter having the same performance as the main filter is used, but is not used during normal operation. However, when replacing a clogged filter, the air path can be switched to a backup filter to replace the filter without interrupting the system. After the filter is replaced, the air path is switched to the updated system, and the use of the backup filter is stopped again. In this way, the backup filter can be used temporarily during the replacement operation.

In addition, if another filter serving as a backup is used even after the clogged filter is replaced, and the other filter is clogged and cannot be used, the original filter is not used. It is also possible to alternately operate two systems of filters, such as switching to a system of filters.

FIG. 4 shows a configuration in which a backup medium performance filter 122 ′ is replaced with a medium performance filter 122 by a damper 122.
a to 122d are connected in parallel so as to be selectively switchable. During operation of the medium performance filter 122,
The dampers 122a and 122b are opened, and the dampers 122a and 122b are opened.
c and 122d are closed. On the other hand, when replacing the medium performance filter 122, the dampers 122a and 122b are closed and the dampers 122c and 122d are opened. in this way,
According to the present embodiment, since the medium-performance filter 122 'which is not clogged is used during the replacement work, the operation of the system does not stop. Note that the open / close state of the damper in FIG. 4 corresponds to the operation of the medium-performance filter 122.

FIG. 5 assumes replacement of either the medium performance filter 122 or the high performance filter 124, or both the medium performance filter 122 and the high performance filter 124. During operation of the medium performance filter 122 and the high performance filter 124, the dampers 122a, 122b, 1
24a is opened and the dampers 122c, 122d, 124
b is closed. On the other hand, when only the medium-performance filter 122 is replaced, the dampers 122a, 122b, and 124b are closed, and the dampers 122c, 122d, and 124a are opened.
Medium-performance filter 1 that is not clogged in this way
According to the present embodiment, the drive of the system does not stop even during the filter replacement work because the 22 'can be used during the replacement work. Furthermore, high performance filter 1
When replacing only 24, the dampers 122c, 122d, 1
24a is closed and the dampers 122a, 122b, 124b are opened. Since the high-performance filter 124 'that is not clogged can be used during the replacement work, according to the present embodiment, the operation of the system does not stop even during the replacement work. Furthermore, the medium performance filter 1
When replacing both the filter 22 and the high-performance filter 124, the dampers 122a, 122b and 124a are closed, and 122c and 1 are replaced.
Open 22d and 124b. The medium-performance filter 122 'and the high-performance filter 1 which are not clogged as described above.
Since 24 ′ is used during the replacement work, according to the present embodiment, the operation of the system does not stop during the replacement work. The open / close state of the damper in FIG. 5 corresponds to the time when the high-performance filter 124 is replaced.

Next, with reference to FIGS. 6 to 16, some preferred embodiments of a particle removing filter constructed according to the present invention which does not generate gaseous impurities will be described.

FIGS. 6A and 6B and FIGS. 7A and 7B
The filter 414 includes a frame 412, 418 made of a metal such as stainless steel or aluminum or a ceramic such as glass, and a spacer 416.
And only the filter paper 414 made of glass fiber material. The frames 412, 418 and the spacer 416 are frame elements, and the filter paper 414 is a filter element. FIG.
As shown in (a) and (b), at the time of manufacturing, first, glass fiber filter paper is woven in a pleated shape using a concave spacer 416. Further, as shown in FIGS. 7A and 7B, the both sides of the glass fiber filter paper 414 sandwiching the spacer 416 are sandwiched between the fluororesin packings 42 without generation of organic gas.
The frames 412 on both sides are compressed mechanically (for example, by screwing) on both sides of the frame 418 via the frame 0. Before use, the particle removal filter 410 is baked at, for example, 200 ° C.
All impurities adhering as dirt to the particle removal filter 410 during the production (mainly gaseous organic matter derived from the atmosphere) are desorbed. 7 (a) and 7 (b) show BB and AA cross sections of the particle removal filter 410, respectively, and a portion corresponding to a cut is hatched. In the AA cross-sectional view (FIG. 7B), the flow direction of the air to be processed in the filter 410 is indicated by a broken arrow 422. This particle removal filter 410 is provided in FIG.
In the same manner as in the embodiment described in (1), it can be attached to a metal duct, but it is preferable to use a fluororesin packing that does not generate an organic gas for the seal of the attachment portion.
Also, as described above, the materials of the spacer 416, the frames 412, 418, and the like are made of a material that does not generate impurity gas, such as a metal or a ceramic.

The particle removal filter 420 shown in FIGS. 8 and 10 also includes only metal frames 412a and 412b made of, for example, stainless steel or aluminum and a filter 414 made of a glass fiber material. As shown in FIG. 8, in the present embodiment, a filter element is formed by bending a filter paper-type flat filter medium 414 made of only glass fibers without a binder into irregularities. The upper and lower end portions 414a of the filter having the uneven shape are formed with metal mold frames 412 formed in an uneven shape corresponding to the uneven shape of the filter.
a and 412b (the upper and lower surfaces of the metal mold frames 412a and 412b shown in FIGS. 10A and 10B). Also, the left and right end portions 414b of the filter having the uneven shape are formed between the flat surfaces of the metal mold frames 412a and 142b (FIG. 10A).
(The left and right side surfaces of the metal mold frames 412a and 412b shown in FIG. In this way, a particle removal filter as shown in FIG. 10A can be configured without using a sealing material that generates gaseous impurities and the like.
FIG. 10A is a perspective view showing a state where the particle removing filter is assembled, and FIG. 10B is a perspective view showing a state where one metal frame 412a is removed. Also for the particle removal filter 420 assembled in this manner, the filter medium 414 together with the metal molds 412a and 412b is, for example, 200 ° C.
Baking to remove all organic matter. In addition,
8 and 10, the frame element is a metal form 4
12a and 412b, and the filter element is the filter 4
14 equivalents.

The particle removing filter 42 shown in FIG.
8 is different from the particle removal filter 420 of FIG. 8 in that a filter element 414 ′ made of only a glass fiber containing no binder is bent in a zigzag manner to form a filter element, and the zigzag filter 414 ′ is formed. It is sandwiched between metal mold frames 412a 'and 412b' formed in a zigzag shape corresponding to the zigzag shape. Except for such a difference in shape, the particle removal filter 420 ′ shown in FIG.
Since it has substantially the same configuration as 20, the detailed description is omitted. In FIG. 9, the frame element corresponds to the metal molds 412a 'and 412b', and the filter element corresponds to the filter 414 '.

FIG. 11 shows how the particle removing filter 420 shown in FIGS. 8 and 10 is attached to the air passages 430a and 430b. All screw bolts 434 are attached to holes formed in the flanges 432a and 432b of the air paths 430a and 430b with nuts 436, and the gap between the air paths 430a and 430b can be adjusted by the nut 436. Then, the particle removal filter 420 according to the present embodiment can be hermetically attached between the air passages 430a and 430b via an inorganic material packing or a fluorine resin packing 438 that does not generate gaseous impurities.

FIGS. 12A to 12D show still another embodiment of the particle removal filter according to the present invention. The particle removal filter 440 is composed of only a metal frame such as stainless steel or aluminum and a metal filter. As shown in FIGS. 12A and 12B, the filter unit 442 of the particle removal filter 440
Are stainless steel meshes 442a, 442b, 442c.
.. are laminated. Further, as shown in FIG. 12C, the filter portion 442 is processed into a pleated shape in order to reduce airflow resistance, and the periphery thereof is fixed with a metal frame 444 as shown in FIG. 12D. Assembled by Although details of the shape of the metal frame 444 are not particularly shown, the metal mold 41 shown in FIG.
Pleated (corrugated) 2a, 412b irregularities
It is changed to. FIG. 12 (c) is the same as FIG.
(D) shows a CC cross section. Of course, also in this case, it is preferable to bake the filter 442 together with the metal frame 444 to remove all organic substances. Of course, also in this case, the filter 442 is connected to the metal frame 44.
It is preferable to bake with 4 to remove all organic substances. In mounting, it is preferable to use a seal member that does not generate gaseous impurities, such as an inorganic material packing or a fluororesin packing. In the above example, an example in which a metal mesh is used as a metal filter is shown, but a metal perforated plate may be used instead. In FIGS. 12A to 12D, the frame element corresponds to the metal frame 444, and the filter element corresponds to the filter 442.

FIGS. 13A to 13D show still another embodiment of the particle removal filter according to the present invention. The particle removal filter 450 is configured by combining a metal frame and a metal mesh for holding a filter medium or a metal perforated plate and a glass fiber filter.
As shown in FIGS. 13A and 13B, the filter unit 452
Is a frame 45 made of a metal mesh or a metal perforated plate.
It is configured by sandwiching a glass fiber filter 454 containing no material that generates gaseous impurities such as a binder between 2a and 452b. A metal fiber filter may be used instead of a glass fiber filter. further,
As shown in FIG. 13C, the filter portion 452 is processed into a pleated shape in order to reduce airflow resistance.
As shown in FIG.
Assembled by fixing at 6. Of course, in this case as well, it is preferable to bake the filter 452 together with the metal frame 456 to remove all organic substances. In mounting, it is preferable to use a seal member that does not generate gaseous impurities, such as an inorganic material packing or a fluororesin packing. FIG.
In (a) to (d), the frame element corresponds to the metal frames 452a, 452b, and 456, and the filter element corresponds to 454.

FIGS. 14 to 16 show still another embodiment of the particle removing filter constructed according to the present invention. The particle removal filter 460 includes only a metal frame 462 (FIG. 16) and a filter portion 464 that does not generate gaseous impurities. Filter section 46
Reference numeral 4 is configured such that a glass fiber filter 466 is sandwiched between an outer frame 464a and an inner frame 464b formed of a cylindrical metal mesh or a perforated plate having one end closed. A metal fiber filter may be used instead of a glass fiber filter. Then, a plurality of the filter portions 464 configured as described above are attached to the metal frame 462 as shown in FIG. In the example shown in FIG. 16, a flat metal frame 462 having an opening corresponding to the size of the open end inner frame 464b is attached to the open end side of the filter portion 464. When assembling, the open end outer frame 464 of the filter portion 464 is used.
a is concentrically attached to the opening of the metal frame 462. That is, the annular open end portion sandwiched between the outer frame 464a and the inner frame 464b is closed by the metal frame 462. In this manner, the particle removal filter 460 can be formed only of the material that does not generate gaseous impurities. Of course, also in this case, the filter 464 is connected to the metal frame 4.
It is preferable to bake together with 62 to remove all organic substances. In mounting, it is preferable to use a seal member that does not generate gaseous impurities, such as an inorganic material packing or a fluororesin packing.

The flow direction of the air to be treated is shown by arrows 468 in FIGS. FIG. 15A shows a case where, for example, in mounting the particle removal filter 460 in the air passage, the open end side of the filter portion 464 is arranged in the upstream direction of the air flow in the air passage, and the closed end side is arranged in the downstream direction. . On the other hand, FIG. 15B is the opposite of FIG.
For example, when the particle removal filter 460 is mounted in the air passage, the filter unit 464 is arranged so that the open end is located downstream of the air flow in the air passage and the closed end is located upstream. 15A and 15B, the air to be processed passes through the glass fiber filter 466 almost radially with respect to the center line of the filter section 464. In addition,
14 to 16, the frame element corresponds to the metal frame 462, the outer frame 464a, and the inner frame 464b, and the filter element corresponds to the glass fiber filter 466.

Next, with reference to FIGS. 17 to 19, several embodiments of a particle removing filter (medium-performance filter) equipped with a filter regenerating apparatus constructed according to the present invention will be described.

In the apparatus 200 shown in FIG. 17, a chamber 202 having an air inlet 204 and an air outlet 206
Expansion chamber 202b on the side of air inlet 204
And a processing chamber 202a on the air outlet side. Inside the processing chamber 202a, a particle removal filter 208 configured according to the present invention that does not generate gaseous impurities,
For example, a metal mesh is a tube-type filter cloth (envelope)
The plurality of filter portions 208a processed into a metal frame 2
08b (for example, equivalent to the metal frame 462 shown in FIG. 16) is stored. The closed ends of the plurality of filter units 208a are attached to a plurality of hooks 202d provided on a rod 202c on the ceiling of the processing chamber 202a.

The apparatus 200 further includes a mechanical vibration type filter regeneration apparatus 210. The filter regeneration device 210 transmits vibration to the tubular particle removal filter 208 suspended by each hook 202d by vibrating the rod 202c. That is, if air treatment is performed for a long period of time, the dust layer of the filter part 208a of the tubular particle removal filter 208 becomes thicker, the pressure loss increases, and the filtration efficiency decreases. Therefore, according to the present embodiment, for example, the pressure loss is measured by a pressure sensor (not shown), and when the pressure loss becomes, for example, about 30 mmH ₂ O, the air is shut off, Is transmitted to the filter unit 208a via the rod 202c and the hook 202d, and the vibration can remove dust adhering to the filter unit 208a. As described above, by appropriately regenerating the filter, the life of the medium-performance filter configured according to the present invention that does not generate gaseous impurities can be extended. The dust that has been blown off is discharged from a hopper 202e at the bottom of the chamber.

FIG. 17 shows an intermittent device 20 for stopping the fan and removing the dust when a certain amount of dust accumulates.
0, but when continuous operation is required for a long time,
It is preferable to use a continuous apparatus 200 'as shown in FIG. FIG. 18A is a side view of the device 200 ′, and FIG. 18B is a front view of the device 200 ′. As shown in the drawing, the device 200 'is a plurality of (three in the example shown) devices 200 shown in FIG. 17 arranged side by side, and includes processing chambers 200A to 200C. Each of the processing chambers 200A to 200C is provided with a corresponding air inlet 204A to 204C, and the purified air is sent from the air outlets 206A to 206C to the clean air duct 212. Thus, according to the present embodiment, the plurality of processing chambers 200A to 200A-2
Since 00C is provided, when a processing chamber requiring a regeneration process appears, the air supply to the chamber is shut off by switching a damper (not shown) to perform a cleaning (filter regeneration process). . As described above, according to the present embodiment, since the sequential reproduction process is performed,
The supply of clean air is not interrupted by the regeneration process.
The cycle of the regeneration process is determined by, for example, the dust concentration or the pressure loss.

FIGS. 17 and 18 show an apparatus having a mechanical vibration type filter regeneration mechanism, but the present invention is not limited to such an example. For example, as shown in FIG. 19, an apparatus 250 having a backwash gas flow type filter regeneration mechanism can be used. The apparatus 250 includes a processing chamber 252 in which a particle removal filter 260 configured according to the present invention is housed. Particle removal filter 26
Numeral 0 has, for example, the same configuration as that shown in FIG. 16 and is made of a plurality of metal meshes (or a glass mesh or a metal fiber sandwiched between a metal mesh for holding a filter medium or a metal porous plate). The filter unit 262 is attached to a metal frame 264. Accordingly, as indicated by the arrow in the figure, the opening 2 of the metal frame 264 is
Air purified by the filter unit 262 can be obtained from the filter 64a.

A plurality of nozzles 261 are provided above the processing chamber 252 at positions corresponding to the openings 264a of the metal panels 264. The nozzle 261 is capable of injecting high-purity nitrogen gas at a higher pressure than a nitrogen source (not shown). The nozzle 261 is connected to the solenoid valve 2
63 is provided to control the injection time and timing of high-pressure nitrogen. Further, a venturi portion 262a is formed above the filter portion 262. Therefore, the nitrogen gas injected at a high speed from the nozzle 261 sucks the surrounding air in the venturi portion 262a and enters the tubular filter portion 262.
The inside of the filter 62 has a high pressure instantaneously, the air flowing into the inside from the outer periphery of the filter 262 flows backward, and the dust adhering to the outer surface of the filter 262 is cleaned. The injection cycle can be adjusted according to the type of dust and the dust concentration. The removed dust is appropriately discharged from a hopper 258 provided at the bottom of the processing chamber 252. In addition,
In FIG. 19, 254 indicates an air inlet, and 256 indicates an air outlet.

[0048]

Next, several embodiments of the gaseous impurity treatment system according to the present invention will be described.

Embodiment 1 First, the gaseous impurity treatment system shown in FIG. 1 (that is, the particle removal filter 420 which does not generate gaseous impurities shown in FIGS. 8, 10 and 11 was used as the downstream filter 120). 1) and three types of chemical filters based on activated carbon fibers as adsorption filter media for gaseous impurities, that is, an acid gas treatment filter, an alkaline gas treatment filter, and an organic gas as in the system shown in FIG. In the case where a treatment filter is stacked in three layers and a conventional ULPA filter (that is, one that itself generates gaseous impurities) is attached downstream of the treatment filter, how the organic substance on the surface of the glass substrate placed downstream of the filter is contaminated is reduced. Were compared. Glass substrate is C
ORNING # 7059, 100mm x 100mm x
1.1 mm ^t . Organic substances adhering to the surface of the glass substrate were all removed by ultraviolet ozone washing, and then subjected to a test, and evaluated by a contact angle evaluation method.

FIG. 21 shows the result. The graph shown in FIG. 21 shows the contact angle on the vertical axis and the exposure time on the horizontal axis. In this example, a contact angle evaluation method was used to evaluate the contamination state of the glass substrate surface.
The contact angle measured by the contact angle evaluation method is the contact angle of a droplet of ultrapure water dropped on the surface of a glass substrate, and the state of contamination of the glass surface with organic substances (carbon / carbon) measured by XPS (X-ray photoelectron spectroscopy). 20) between the silicon angle) and the contact angle.
There is a relationship as shown in The carbon / silicon ratio is an index proportional to the amount of organic substances attached to the surface, and the contact angle is an index indicating the degree of contamination of the surface with hydrophobic organic substances. Therefore, by observing the contact angle, the state of organic substance contamination on the surface of the glass substrate can be measured simply and in a short time. Note that the XPS and the contact angle measuring method are not directly related to the present invention, and thus detailed description thereof is omitted. For details, refer to Japanese Patent Application No. 7-171373 filed by the same applicant as the present applicant.

The change with time in the contact angle of the glass surface was determined by comparing the case where the glass substrate immediately after the cleaning was placed downstream of the high-performance filter according to the present embodiment where no impurity gas was generated, with the conventional glass substrate. A comparison was made for the case where the filter was placed downstream of the ULPA filter. As shown in FIG. 21, in the case of the present invention, the contact angle increased by only 3 degrees even after 3 days, but when the conventional ULPA filter was used, the increase in the contact material from the constituent materials of the ULPA filter was observed. Due to the effect of degassing, the contact angle increased by 20 degrees. In FIG. 21,
Data when exposed to a clean room atmosphere without a chemical filter is also shown for reference.

Embodiment 2 Similarly, in the gaseous impurity treatment system shown in FIG. 2, a high performance filter 120 'is constituted by a metal frame and a glass fiber material according to the present invention shown in FIGS. 8, 10 and 11. High performance filter 4
No. 20 was attached, and a glass substrate immediately after washing was placed on the downstream side of the filter in the same manner as in Example 1. When the change over time in the contact angle was examined, no increase in the contact angle was observed even after 3 days.

Embodiment 3 Further, in the gaseous impurity treatment system shown in FIG. 3, as the medium performance filter 122, a medium performance filter made of a metal mesh filter provided with a lateral vibration type removing mechanism shown in FIG. And a high-performance filter 124 comprising a metal frame and a glass fiber material according to the present invention shown in FIG. 8, FIG. 10 and FIG.
20 was attached and the glass substrate immediately after washing was placed downstream of the high-performance filter in the final stage in the same manner as in Example 1, and the time-dependent change in the contact angle was examined. Not observed.

The preferred embodiments of the gaseous impurity treatment system and the particle removal filter according to the present invention have been described with reference to the accompanying drawings.
It goes without saying that the present invention is not limited to such an example. It is clear that, within the scope of the technical idea described in the claims, those skilled in the art can arrive at various modifications and alterations, and those modifications are also described.
It is understood that they belong to the technical scope of the present invention.

For example, in the above-described embodiment, an example is shown in which an inorganic material such as metal, ceramics and glass fiber, a fluororesin packing or the like is used as a material that does not generate gaseous impurities. It is not limited to the example. In a material that does not generate so-called gaseous impurities in the present invention, volatile components are removed by heat treatment, and gaseous impurities (phthalate esters (D
Materials that eliminate generation of OPs, DBPs and other resin plasticizers, siloxanes (such as sealing materials), phosphate esters (such as TBP and other resin plasticizers), and BHT (resin participation inhibitors).

For example, among the constituent materials of ordinary filters, various organic resins are used for gaskets, adhesives, filter media, etc., and these materials are baked at 90 ° C., for example. Thus, it is possible to eliminate the generation of gaseous organic substances involved in surface contamination.

The effect of eliminating the generation of gaseous impurities by heat treatment using a urethane resin used as a sealing material for a filter or the like as an evaluation material will be described below. Inside, seal the clean silicon wafer and the evaluation material together,
Left for 3 days. As an evaluation material, an untreated urethane resin and a heat-treated urethane resin were used, and the value of a pure drop contact angle on the silicon wafer surface after being left was compared.

As a result, the contact angle of the clean silicon wafer from which organic substances adhering to the surface were completely removed by ultraviolet / ozone cleaning was about 3 degrees. Then, the surface of the silicon wafer sealed together with the untreated urethane resin was contaminated by degassing from the urethane resin, and the contact angle increased to 20 degrees or more.
On the other hand, the contact angle of the heat-treated silicon wafer was almost the same as that of a clean silicon wafer.
From the above, it has been found that even when a material containing an organic resin is used, the removal of volatile components by heat treatment can reduce the generation of gaseous organic substances involved in surface contamination.

[0059]

As described above, according to the present invention,
A material that does not generate gaseous impurities is removed downstream of the gaseous impurity removing means that removes gaseous impurities contained in the untreated air but generates particulate impurities in the treated air. Since the filter means for removing the particulate impurities composed only of the gaseous impurity is provided, it is also possible to remove the particulate impurities generated by the gaseous impurity removing means, and the apparatus itself does not become a pollution source.

[Brief description of the drawings]

FIG. 1 is a schematic configuration diagram showing one embodiment of a gaseous impurity removal system according to the present invention.

FIG. 2 is a schematic configuration diagram showing another embodiment of the gaseous impurity removal system according to the present invention.

FIG. 3 is a schematic configuration diagram showing still another embodiment of the gaseous impurity removal system according to the present invention.

FIG. 4 is a schematic configuration diagram showing an embodiment in which a backup filter is provided in the gaseous impurity removal system according to the present invention.

FIG. 5 is a schematic configuration diagram showing another embodiment in which a backup filter is provided in the gaseous impurity removal system according to the present invention.

FIG. 6 is a schematic exploded view showing one embodiment of a particle removal filter according to the present invention.

FIG. 7 is a cross-sectional view of the particle removal filter shown in FIG.

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

FIG. 9 is a schematic exploded view showing still another embodiment of the implementation of the particle removing filter according to the present invention.

10 (a) is a schematic perspective view after assembling the particle removal filter shown in FIG. 8, and FIG. 10 (b)
It is a perspective view which shows the outline of the metal frame used for the particle removal filter shown in FIG.

FIG. 11 is a schematic explanatory view showing a state in which the particle removal filter shown in FIG. 8 is attached to an airway.

FIG. 12 is an explanatory view showing still another embodiment of the implementation of the particle removal filter according to the present invention.

FIG. 13 is an explanatory view showing still another embodiment of the implementation of the particle removal filter according to the present invention.

FIG. 14 is an explanatory diagram showing still another embodiment of the particle removal filter according to the present invention.

FIGS. 15A and 15B are explanatory diagrams showing the state of air flow of the particle removal filter shown in FIG. 14, wherein FIG. 15A shows a case where the air flow is downward, and FIG. 15B shows a case where the air flow is upward.

FIG. 16 is a schematic perspective view showing a state after assembling the particle removal filter shown in FIG. 14;

FIG. 17 is a configuration diagram showing one embodiment of a particle removal filter with a filter regeneration mechanism according to the present invention.

FIG. 18 is a configuration diagram showing another embodiment of a particle removal filter with a filter regeneration mechanism according to the present invention.

FIG. 19 is a configuration diagram showing still another embodiment of a particle removal filter with a filter regeneration mechanism according to the present invention.

FIG. 20 is a graph showing the relationship between the contact angle and the state of organic substance contamination of the glass substrate in the contact angle determination method.

FIG. 21 is a graph showing a relationship between a contact angle of a droplet of ultrapure water dropped on a glass substrate and an exposure time, and has a particle removal filter according to the present invention composed only of a material that does not generate gaseous impurities. When a gaseous impurity removal system is used, when a conventional gaseous impurity removal system equipped with a conventional ULPA filter having a material that generates gaseous impurities downstream of the chemical filter is used, the gaseous impurities are removed. No clean room atmosphere is used, respectively.

[Explanation of symbols]

100 Gaseous impurity treatment system 102 Casing 110 chemical filter 120 Particle removal filter that does not generate gaseous impurities 410 Particle Removal Filter 412 frames 414 Filter 416 spacer

Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI B01D 46/42 B01D 46/42 C 46/52 46/52 CZ (56) References JP-A-7-136450 (JP, A) JP JP-A-6-302487 (JP, A) JP-A-3-183780 (JP, A) JP-A-2-26605 (JP, A) JP-A-5-64712 (JP, A) JP-A-5-23522 (JP , A) JP-A-61-149218 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B01D 46/00-46/54

Claims (3)

(57) [Claims] 1. A gaseous impurity removal means for removing gaseous impurities contained in untreated air, which itself generates particulate impurities in the treated air, and a downstream side of the gaseous impurity removal means. A filter means comprising a high-performance filter for removing particulate impurities composed only of a material that does not generate gaseous impurities, wherein the gaseous impurity treatment system for supplying the generated clean air, The impurity removal means is the clean room
A compressor for compressing air in the system, and heating and contacting the air.
A reaction tower for reacting with the medium, and cooling the treated air.
Including a catalytic catalytic combustion cylinder comprising a heat exchanger
A gaseous impurity treatment system, characterized in that: 2. A gaseous impurity removal means for removing gaseous impurities contained in untreated air, which itself generates particulate impurities in the treated air, and a downstream side of the gaseous impurity removal means. In the gaseous impurity processing system, which comprises medium-performance and high-performance filters for removing particulate impurities composed only of a material that does not generate gaseous impurities, and which supplies the generated clean air , The gaseous impurity removing means includes a fluidized bed adsorbing section, a seal
Fluidized bed adsorption tower consisting of
A gaseous impurity treatment system characterized by including: 3. The gaseous impurities contained in the untreated air are:
Removes particulate impurities in the treated air
A means for removing gaseous impurities generated, and a gaseous impurity disposed downstream of the means for removing gaseous impurities.
Particulate impurities composed only of materials that do not generate pure substances
Filter means for removing the
In the gaseous impurity treatment system for supplying a filter , the filter means includes a medium-performance filter and a high-performance filter.
Or the high-performance filter
Only the filter means and the filter means
Backup filter means of the filter means, wherein the backup filter means exchanges the filter means .
Before in Symbol performance replace clean air flow path is cut in-over Fi
A gaseous impurity treatment system, wherein the gaseous impurity treatment system is connected to at least one of a filter and the high-performance filter .