JP3759062B2 - Clean gas adjustment device - Google Patents

Description

【００４７】
実施例３
硝酸と硫酸を使用して酸洗浄したクリーンルーム内の空気（ＮＯ_xとＳＯ_xを１０〜５０ｐｐｍ含有）から、図１に示した装置によって水分と微粒子とＨＣを除去した。これによって得られた清浄化空気にウエハを暴露し、接触角を測定した。また本発明に係る気体調製装置の出口で微粒子濃度と非メタンＨＣの濃度を測定した。さらに除湿器出口での水分濃度も測定した。さらに比較の装置およびクリーンルーム内の処理前の空気にウエハを暴露した場合についても接触角の測定を行った。
【００４８】
試験条件
処理前のクリーンルーム内での水分の濃度：４０〜６０％
処理前のクリーンルーム内での微粒子濃度：クラス１００００
処理前のクリーンルーム内での非メタンＨＣの濃度：０.８２ｐｐｍ
除湿器：電子除湿器（Ｐeltier effect方式）（伸栄産業(株)製）
除塵フィルタ：ＵＬＰＡ（日本ポール(株)製、ガスクリーンフィルタＳＧＬＦ６１０１）
吸着材：(１)シリカゲル（ＨＣ吸着用）(中粒、ＳＶ：１０００ｈ^-1）（和光純薬(株)製）
(２)アルカリを添着した活性炭（ＮＯ_xとＳＯ_x吸着用、ＳＶ：１０００ｈ^-1）（ツルミコール(株)製）を上記シリカゲルの下流側に装着したもの
接触角測定器：協和界面科学（株）製、ＣＡ−Ｄ型接触角計
水分測定器：電子式湿度センサ
空気へのウエハの暴露時間と測定された接触角θとの関係を図３に示す。図３において、本発明のもの（Ｆ）(除湿器、除塵フィルタ、吸着材（２）を使用）は白丸−○−で示し、比較として、本発明のもの（Ｆ）から除湿器を外したもの（Ｇ）は黒白丸で示し、また本発明のもの（Ｈ）(除湿器、除塵フィルタ、吸着材（１）を使用）は白四角−□−で示す。さらに比較として、クリーンルーム内の処理前の空気に暴露したもの（Ｉ）を黒丸−●−で示す。
【００４９】
本発明の装置（Ｆ）および（Ｈ）の出口での微粒子濃度はクラス１０以下で、非メタンＨＣの濃度は０.１ｐｐｍ以下であった。また除湿器出口での水分の濃度は３０〜３５％であった。
【００５０】
実施例４
図１に示した装置（ただし除塵フィルタと吸着材は下記のものを使用）によって、クリーンルーム内の空気から水分と微粒子とＨＣを除去した。これによって得られた清浄化空気にガラス基板を暴露し、接触角を測定した。また本発明に係る気体調製装置の出口で微粒子濃度と非メタンＨＣの濃度を測定した。さらに除湿器出口での水分濃度も測定した。また図１に示した装置から除湿器を外したもの、さらにクリーンルーム内の処理前の空気にガラス基板を暴露した場合についても接触角の測定を行った。
【００５１】
試験条件
処理前のクリーンルーム内での水分の濃度：４０〜６０％
処理前のクリーンルーム内での微粒子濃度：クラス１００００
処理前のクリーンルーム内での非メタンＨＣの濃度：０.６４ｐｐｍ
除湿器：電子除湿器（Ｐeltier effect方式）（伸栄産業（株）製）
ＨＣ吸着材：シリカゲル（中粒、ＳＶ：１０００ｈ^-1）（和光純薬（株）製）と、このシリカゲルの下流側に繊維状ホウケイ酸ガラスを四フッ化樹脂をバインダとしてフィルタ状に成形したもの（ＳＶ：１００００ｈ^-1）を装着したもの
除塵フィルタ：上記の繊維状ホウケイ酸ガラスをフィルタ状に成形したもので兼用
接触角測定器：協和界面科学(株)製、ＣＡ−Ｄ型接触角計
水分測定器：電子式湿度センサ
ガラス基板の前処理：洗剤とアルコールで洗浄後、Ｏ₃発生下で紫外線照射
空気へのガラス基板の暴露時間と測定された接触角θとの関係を図４に示す。図４において、本発明のもの（Ｊ）(除湿器、除塵フィルタ、ＨＣ吸着材を使用）は白丸−○−で示し、比較として、本発明のもの（Ｊ）から除湿器を外したもの（Ｋ）は黒白丸で示す。また比較として、クリーンルーム内の処理前の空気に暴露したもの（Ｌ）を黒丸−●−で示す。
【００５２】
本発明の装置（Ｊ）の出口での微粒子濃度はクラス１０以下で、非メタンＨＣの濃度は０.１ｐｐｍ以下であった。また除湿器出口での水分の濃度は２５〜３０％であった。
【００５３】
【発明の効果】
本発明によれば以下のような効果を奏する。
本発明の方法により気体中の微粒子を除去するとともに炭化水素を吸着および／または吸収することによって、清浄な気体が得られる。この清浄化気体を半導体や液晶などの基材や基板上に暴露しておくと基材や基板の表面の汚染が防止される。
【００５４】
また被処理気体中での炭化水素以外のＮＯ_x、ＳＯ_xなどのガス状有害成分の濃度が高い場合、これら有害成分の除去法（例えば本発明者がすでに提案した方法）を適宜選択し、それを本発明に係る炭化水素の吸着材および／または吸収材と組み合わせることによって、汚染がよりいっそう効果的に防止される。
【００５５】
さらに、炭化水素を除去するにあたって、被処理空気を除湿し、水分を一定濃度以下にすることによって、吸着材による炭化水素除去性能が長期間にわたって安定して維持される。これにより、吸着材の交換頻度が減少し、実用性が向上する。
【図面の簡単な説明】
【図１】 図１は本発明の装置を示し、半導体製造工場におけるエアーナイフ用の供給空気の浄化に適用した例である。
【図２】 図２は、空気へのガラス基板またはウエハの暴露時間と測定された接触角θとの関係を示すグラフである。
【図３】 図３は、空気へのガラス基板またはウエハの暴露時間と測定された接触角θとの関係を示すグラフである。
【図４】 図４は、空気へのガラス基板またはウエハの暴露時間と測定された接触角θとの関係を示すグラフである。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method and apparatus for preparing a clean gas to be brought into contact with a substrate or a substrate surface, and in particular, prevents contamination of raw materials, semi-finished products, product substrates and substrate surfaces in advanced industries such as semiconductor manufacturing and liquid crystal manufacturing. The preparation of a clean gas for the purpose.
[0002]
The fields of application of the present invention are, for example, (1) prevention of wafer contamination in the semiconductor manufacturing process, (2) prevention of glass substrate contamination in the liquid crystal manufacturing process, and (3) prevention of substrate contamination in the precision machine manufacturing process. Examples of the application location of the method and apparatus for preparing a clean gas according to the present invention include spaces in clean rooms in semiconductor manufacturing factories, liquid crystal manufacturing factories, precision machine factories, etc., such as safety cabinets, clean boxes, and valuables storages. , Including wafer storage, sealed transport space for valuables, clean sealed space in the presence of various gases or under reduced pressure or vacuum, transport space, space containing gas supplied to cleaning equipment, air knife supply air There is space.
[0003]
[Prior art]
The prior art will be described below with reference to an example of clean air in a semiconductor manufacturing factory.
[0004]
In a clean room, particulate matter (particulate matter) and gaseous matter such as extremely low concentration hydrocarbon (HC) other than methane in the air caused by automobile exhaust gas, etc., become a problem as pollutants. In particular, HC needs to be removed because the extremely low concentration in normal air (room air and outside air) as a gaseous harmful component causes contamination. In addition, various solvents (alcohols, ketones, etc.) generated during work in a clean room also become a problem as contaminants.
[0005]
That is, if the above-mentioned contaminants (fine particles and gaseous contaminants) are deposited on the substrate surface of a wafer, semi-finished product, or product, the substrate surface is likely to be damaged, causing a reduction in the productivity (yield) of the semiconductor product. Therefore, it is necessary to remove contaminants. Both fine particles and gaseous substances increase the contact angle of the substrate surface, but it has been found that HC tends to increase the contact angle particularly in a normal clean room. Here, the contact angle is a contact angle of wetting with water and indicates the degree of contamination of the substrate surface. That is, when a hydrophobic (oil-based) substance adheres to the substrate surface, the surface repels water and becomes difficult to wet. This increases the contact angle between the substrate surface and the water droplets. Therefore, if the contact angle is large, the degree of contamination is high. Conversely, if the contact angle is small, the degree of contamination is low.
[0006]
Conventional clean room air purification methods or devices therefor can be broadly classified into (1) mechanical filtration methods (HEPA filters, etc.), (2) electrostatically collecting fine particles, charging or conducting by high voltage. There is a filtration method (such as a HESA filter) using a neutral filter. All of these methods are intended to remove fine particles and are ineffective for removing gaseous pollutants that increase the contact angle, such as hydrocarbons (HC) other than methane.
[0007]
On the other hand, combustion decomposition methods, O ₃ decomposition methods, and the like are known as methods for removing HC, which is a gaseous pollutant. However, these methods are ineffective in removing extremely low concentrations of HC contained in the air introduced into the clean room.
[0008]
Further, gaseous harmful components other than HC include SO _x , NO _x , HCl, and NH ₃ , and these removal methods include neutralization reactions and oxidation reactions using appropriate alkaline substances and acidic substances. The method to use is known. However, these methods are less effective when the concentration of the component is extremely low as contained in the air introduced into the clean room.
[0009]
The present inventors have already proposed a method and an apparatus using an adsorbent or an absorbent to prevent the increase in the contact angle as a method and apparatus for preventing contamination of the substrate or the substrate surface (Japanese Patent Application No. No. 3-341802 and Japanese Patent Application No. 4-180538). Although these methods and apparatuses are effective depending on the application field, further improvement is required to further increase the practicality.
[0010]
[Problems to be solved by the invention]
That is, in order to improve the productivity of semiconductor products, it is necessary to remove particulate substances and gaseous harmful components that increase the contact angle. Therefore, an object of the present invention is to provide a method and an apparatus for preparing a clean gas having a sufficiently low concentration of particulate harmful substances that increase the concentration of fine particles and the contact angle between the substrate and the substrate surface.
[0011]
[Means for Solving the Problems]
In order to solve the above problems, according to the present invention, an apparatus for adjusting a clean gas having a non-methane hydrocarbon concentration of 0.2 ppm or less from a gas in a clean room, comprising a dehumidifying means, an adsorbing means and / or an absorbing means, And an apparatus for adjusting the clean gas.
[0012]
Further, according to the present invention, the gas in contact with the base material or the substrate is purified by the dust removing means and the adsorption and / or absorption means, and the non-methane hydrocarbon concentration in the gas becomes 0.2 ppm or less. Thereafter, a method is provided that exposes the gas to a substrate or substrate surface.
[0013]
Furthermore, according to the present invention, there is provided a method for preparing a clean gas to be brought into contact with the surface in order to prevent contamination of the surface of a substrate or a substrate, wherein the moisture concentration in the gas to be treated is 50% (RH) by a dehumidifying means. ) After the following, it is characterized in that the fine particle concentration in the gas is class 10 or less and the non-methane hydrocarbon concentration is 0.2 ppm or less by purifying by dust removing means and adsorption means and / or absorption means. A method is provided.
[0014]
Furthermore, according to the present invention, there is provided an apparatus for preparing a clean gas to be brought into contact with the surface in order to prevent contamination of the surface of the base material or the substrate, wherein the moisture concentration in the gas to be treated is 50 at the inlet of the apparatus. % (RH) or less dehumidifying means, and downstream of the dehumidifying means, dust removing means for reducing the concentration of fine particles in a gas whose water concentration is reduced to 50% or less to class 10 or less, and non-methane hydrocarbon concentration There is provided an apparatus provided with an adsorbing means and / or an absorbing means of 0.2 ppm or less.
[0015]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail by taking as an example the case where the gas in contact with the substrate or the substrate surface is air.
[0016]
The dust removing means in the present invention may be any as long as it can remove fine particles in the air to a low concentration. Usually, a known dust filter that efficiently collects fine particles to a low concentration is used. In general, HEPA filters, ULPA filters, and electrostatic filters are preferable because they are simple and effective. Usually, one or more of these filters are used in appropriate combination. By removing the fine particles, the fine particle concentration is set to class 10 (10 particles / ft ³ ) or less. Here, the class is a unit of fine particle concentration and represents the number of fine particles in 1 ft ³ .
[0017]
In order to remove non-methane hydrocarbons, that is, gaseous harmful components, materials that adsorb and / or absorb these components that increase the contact angle are used. Non-methane hydrocarbons cause contamination at concentrations in normal air (room air and outside air). Among various non-methane hydrocarbons, the component that increases the contact angle is considered to vary depending on the type of substrate (wafer, glass material, etc.) and the type and properties of the thin film on the substrate. As a result of intensive studies, the present inventor has found that it is effective to remove non-methane hydrocarbons as an index to 0.2 ppm or less, preferably 0.1 ppm or less.
[0018]
As the adsorbent, activated carbon, silica gel, synthetic zeolite, molecular sieve, polymer compound (for example, styrene polymer, styrene-divinylbenzene copolymer), glass, fluorine compound, metal, or the like is used.
[0019]
As the glass material, an oxide glass system such as silicate glass and phosphate glass is generally used. As the silicate glass, borosilicate glass (main component: N ₂ O—B ₂ O ₃ —SiO ₂ ) is particularly preferable because it is easy to mold, has a high adsorption effect, and is inexpensive. Further, when the glass surface is coated with a metal thin film such as Ti, Au, Al, or Cr, the adsorption effect is enhanced.
[0020]
Fluorine compounds include tetrafluoride resin, 4-hexafluoride resin, PFA resin, ethylene trifluoride resin, ethylene tetrafluoride-ethylene copolymer, vinylidene fluoride resin, vinyl fluoride resin, fluorinated graphite, Examples include Teflon (registered trademark).
[0021]
Glasses and fluorine compounds can be used in filter shapes, fiber shapes, net shapes, spherical shapes, pellet shapes, lattice shapes, rod shapes, pleated shapes, and the like. In general, a filter shape is preferable because it has a large adsorption effect. As an example of a molding method in the case of using in a filter shape, there is a method in which a fluorine compound resin is used as a binder and a fibrous glass material is used in a filter shape. When used in such a filter shape, the dust removal performance is added to the HC removal performance, so the filter configuration is simplified. Therefore, it is preferable to incorporate such an adsorbent into the pollution control device depending on the field of use, the device scale, and the device shape.
[0022]
Examples of the metal include Fe, Ag, Ni, Cr, Ti, Au, and Pt. Powder, plate, sponge, linear, fiber, or those added to an appropriate carrier, for example, silica-alumina gel Further, a shape in which Ag is supported on the surface and a shape in which Ag is supported on zirconium phosphate can be suitably used.
[0023]
Among the adsorbents, activated carbon, silica gel, synthetic zeolite, polymer compound, glass, fluorine compound, and metal are more preferable because of their high adsorption effect. These adsorbents can be used alone or in combination of two or more (see Japanese Patent Application No. 3-341802 and Japanese Patent Application No. 4-180538). As will be described later, since it is considered that there are a plurality of types of HC involved in increasing the contact angle, the use of two or more types of adsorbents in combination increases the life. That is, there is a limit in collecting all HCs involved in increasing the contact angle depending on the collection by one kind of adsorbent, so if adsorbents with different adsorption characteristics are used in combination as appropriate through experiments. It is effective.
[0024]
In addition, since the degree of HC influence varies depending on the type of glass substrate or the surface condition of the substrate, a preliminary test is appropriately performed depending on the application field, device scale, shape, device usage conditions, shared gas, required performance, economy, etc. A suitable material can be selected from the adsorbents.
[0025]
In the present invention, the air to be treated is dehydrated, dehumidified, or dehumidified before air is passed through the adsorbent, which improves the adsorbent adsorption performance and extends the life. For this purpose, a well-known system such as a cooling system, an adsorption system, an absorption system, a compression system, or a system using membrane separation can be used, and the application field, scale, shape, and usage conditions (for example, large size) of the apparatus of the present invention can be used. Preliminary tests are performed as appropriate under atmospheric pressure or pressure), and one type or two or more types are used in appropriate combination. As the dehumidifying method, it is preferable to use a method in which the dehumidifying performance is stably maintained over a long period of usually several months to half a year or more. In particular, the cooling type and / or the adsorption type are simple and effective. As the cooling type, the electronic dehumidification method and the cooling coil method are preferable. As the adsorption type, the dehumidification and regeneration of the dehumidifier itself are continuously performed for a long period of time (fixed type, rotary type, etc.). It is effective. Silica gel, zeolite, activated carbon, activated alumina, magnesium perchlorate, calcium chloride, etc. can be used as the dehumidifying material by the adsorption method. Of these, silica gel and zeolite are preferable because they have an HC removal effect, can be recycled, and can be used for a long time.
[0026]
If dehumidification is performed so that the moisture concentration in the gas to be treated is 50% (RH: relative humidity) or less, preferably 30% (RH) or less, the HC adsorption performance of the adsorbent is improved and the performance is stable for a long time. Maintained. The dehumidification method and the limit moisture concentration can be determined by conducting a preliminary test as appropriate according to the type and scale of the applied device, the type of HC removal material, the required performance, the economy, and the like.
[0027]
By performing dehumidification, the HC removal performance of the adsorbent is stably maintained for a long period of time. In particular, the performance is remarkably stabilized when a hydrophobic material such as silica gel or a fluorine compound is used as the adsorbent.
[0028]
When the adsorbent is used, the adsorbent can be simultaneously regenerated by PSA (pressure swing adsorption) or TSA (thermal swing adsorption) in addition to the above-described usage method (with dehumidification).
[0029]
Any HC absorbent can be used as long as it can react with and immobilize HC at a low concentration. In general, a reaction with Cr ⁶⁺ in the presence of H ₂ SO ₄ or a reaction with I ₂ O ₅ in the presence of H ₂ S ₂ O ₇ can be used. The former is effective for low molecular weight HC, and the latter is effective for high molecular weight HC. For example, it is used by impregnating an aqueous salt solution containing H ₂ SO ₄ acidic hexavalent chromium on the surface of a carrier such as glass beads or an appropriate shape (for example, pellets) of zeolite or alumina. Absorption means reaction absorption by a chemical reaction.
[0030]
The use conditions of the adsorbent and / or absorbent material can be determined by appropriately conducting preliminary tests depending on the field of application of the apparatus of the present invention, apparatus scale, shape, required performance, and the like. The space velocity (SV) of the air to be treated in the apparatus is usually 100 to 20000 (h ⁻¹ ), preferably 100 to 5000 (h ⁻¹ ).
[0031]
The above is a description of the embodiment of the present invention in the case of removing extremely low concentration HC in normal air. In general, substances that contaminate the substrate or the substrate surface and increase the contact angle are (1) harmful gases such as SO _x , NO _x , HCl, NH ₃ , (2) fine particles, (3) HC, As a result of study by the present inventor, the contact angle is determined in N ₂ used in normal air (environmental atmosphere in a normal clean room) or in a clean room such as a semiconductor manufacturing factory or a liquid crystal manufacturing factory. On the other hand, the influence of fine particles and HC is large. That is, generally, SO _x , NO _x , HCl, and NH ₃ have little influence on the increase in the contact angle at a normal concentration level in air. Therefore, the effect is obtained by dust removal and removal of HC. But to SO _x and the like harmful gas when these concentration is high occurred in or around the cleanroom affected by these gas components, even if lower to the extent that these concentrations are not affected by normal, group When the material or the substrate is sensitive or the surface is in a special state (for example, when a special thin film is coated on the surface of the base material), it may be affected. In such a case, a method (apparatus) (Japanese Patent Application No. 3-22686) proposed by the present inventor for irradiating a harmful gas with ultraviolet rays and / or radiation to make the gas fine particles and collecting the fine particles. It is preferable to use them in appropriate combinations. In such a case, another known harmful gas removing material such as activated carbon or ion exchange resin may be used in appropriate combination. As the activated carbon, an acid, alkali, or the like can be added or appropriately modified by a known method.
[0032]
Furthermore, for the purpose of removing HC, the method (Japanese Patent Application No. 3-105092) that has been proposed by the present inventor and finely collects HC by ultraviolet and / or radiation irradiation can also be used. .
[0033]
FIG. 1 shows an example in which the method of the present invention is applied to purification of supply air for an air knife in a semiconductor manufacturing factory. In FIG. 1, 1 is a clean room of class 10000, and air 2 includes a dehumidifier 3, an adsorbent 4 that adsorbs gaseous harmful components (mainly HC in this example) that increase the contact angle, and a dust filter 5. It is processed in the clean room 1 by the gas preparation device 6. After passing through the device 6, the air 7 is clean air from which dust is removed and gaseous harmful components are removed, and is supplied to an air knife device 8 for cleaning the wafer (substrate).
[0034]
Hereinafter, this example will be described in detail. The outside air 9 before entering the clean room 1 is first processed by the coarse filter 10 and the air conditioner 11. Next, when the air enters the clean room 1, the dust is removed by the HEPA filter 12, and the air becomes a class 10000 concentration air 13 in which extremely low concentration HC coexists. That is, the extremely low concentration HC mainly generated from the automobile is not removed by the coarse filter 10, the air conditioner 11, and the HEPA filter 12, and thus is introduced into the clean room 1. The concentration of HC in the air 13 is 0.5 to 0.8 ppm for non-methane HC.
[0035]
The air 2 in the clean room 1 containing moisture (RH 40-60%), fine particles (class 10000), and extremely low concentration of HC is first dehumidified by a dehumidifier (dehumidifier) 3 so that the moisture becomes a certain concentration or less. The The dehumidifier of this example is based on an electronic dehumidification method, and is operated so that the humidity (RH 40 to 60%) in the clean room 1 is 30% or less.
[0036]
The dehumidified air is then processed by the HC adsorbent, that is, the gas adsorption / removal device 4, thereby removing extremely low concentration of HC. The HC adsorbent 4 may be any material as long as it removes extremely low concentrations of HC in the normal atmosphere. In this example, silica gel is used as the adsorbent 4. Thereby, non-methane HC in the air is removed to a concentration of 0.1 ppm. Silica gel adsorbs moisture when the moisture in the introduced air 2 is high, and the performance deteriorates. Therefore, the moisture is previously removed by the dehumidifier 3 as described above.
[0037]
Next, fine particles in the air are removed by a dust removing filter (dust removing device) 5. The position of the dust removal filter 5 can be upstream of the HC adsorbent 4, or downstream of the HC adsorbent as in this example, or both upstream and downstream. However, it is usually preferable that at least one is installed on the downstream side as in this example for the sake of safety in the case where fine particles flow out from the adsorbent 4. The dust filter 5 may be any filter as long as it can efficiently collect fine particles having a concentration of class 10,000 in a clean room and fine particles flowing out from the adsorbent. In this example, a ULPA filter is used. The ULPA filter removes fine particles to class 10 or lower.
[0038]
In this example, HC removal is performed by an adsorbent, but an adsorbent (reactant with extremely low concentration of HC) may be used instead of the adsorbent. Moreover, you may use an adsorbent and an absorber simultaneously.
[0039]
The combination of the method (apparatus) already proposed by the present inventor and the method of the present invention, and the use and combination of materials for removing harmful gases other than HC can be appropriately selected and used. Moreover, the use conditions of a dust removal filter, an adsorbent, and / or an absorber can be determined as appropriate. That is, these are preliminarily tested depending on the concentration and type of pollutants (fine particles, HC, other harmful gases) in the clean room to be used, the type of equipment, structure, scale, required performance, efficiency, economy, etc. Can be decided.
[0040]
In the present embodiment, the case where the medium is air has been described, but it goes without saying that the present invention can be similarly implemented even when fine particles and gaseous harmful substances are contained as impurities in other gases such as nitrogen and argon.
[0041]
The space to which the present invention can be applied refers to under pressure, under reduced pressure, and under vacuum in addition to the above-described atmospheric pressure, and can be similarly implemented.
It is said that the HC component in the air is a mixture of several hundreds or thousands of components, and it is unclear how much of these many types of HC components are involved in increasing the contact angle. . For this reason, there are many unclear points about the mechanism for preventing the increase in the contact angle due to the adsorbent and / or the absorbent, but it is considered as follows. That is, it is presumed that the influence of a particularly high molecular weight substance or a highly active substance among the HC components is large for increasing the contact angle, and these are effectively adsorbed and collected by the adsorbent or absorbent.
[0042]
Example 1
With the apparatus shown in FIG. 1, moisture, fine particles and HC were removed from the air in the clean room. The glass substrate was exposed to the purified air thus obtained, and the contact angle was measured. Further, the fine particle concentration and the non-methane HC concentration were measured at the outlet of the gas preparation device according to the present invention. Furthermore, the water concentration at the outlet of the dehumidifier was also measured. Also, the device shown in FIG. 1 with the dehumidifier removed, the dehumidifier and the HC adsorbent removed (ie, only the dust filter is used), and the dehumidifier and the dust filter removed (ie, only the HC adsorbent used) In addition, the contact angle was measured, and the contact angle was also measured when the glass substrate was exposed to air before treatment in a clean room.
[0043]
Moisture concentration in clean room before processing test conditions: 40-60%
Fine particle concentration in clean room before treatment: class 10,000
Non-methane HC concentration in clean room before treatment: 0.51 ppm
Dehumidifier: Electronic dehumidifier (Peltier effect method) (manufactured by Shinei Sangyo Co., Ltd.)
Dust removal filter: ULPA (manufactured by Nippon Pole Co., Ltd., Gas Clean Filter SGLF6101)
HC adsorbent: silica gel (medium grain, SV: 1000 h ⁻¹ ) (manufactured by Wako Pure Chemical Industries, Ltd.)
Contact angle measuring device: manufactured by Kyowa Interface Science Co., Ltd., CA-D type contact angle meter Moisture measuring device: Electronic humidity sensor Pretreatment of glass substrate: After cleaning with detergent and alcohol, to UV irradiation air under generation of O ₃ FIG. 2 shows the relationship between the exposure time of the glass substrate and the measured contact angle θ. In FIG. 2, the present invention (A) (dehumidifier, dust filter, silica gel is used) is indicated by a white circle-○-, and the dehumidifier is removed from the present invention (A) for comparison (B). Is indicated by a black and white circle. For comparison, those exposed to air before treatment in a clean room (C) (black circle-●-), those exposed to air passed through a dust filter only (D) (white square-□-), and HC adsorption Also shown is the one (E) (black square) exposed to air passed through the material alone.
[0044]
The frequency (contact angle detection lower limit) that can detect the contact angle of the contact angle meter used is 3 to 4 degrees. In the case of the present invention using a dehumidifier, a dust filter, and silica gel at the same time, the detection limit (↓ )showed that. The concentration of fine particles at the outlet of the apparatus (A) of the present invention was class 10 or less (measuring instrument: light scattering particle counter), and the concentration of non-methane HC was 0.1 ppm or less (measuring instrument: gas chromatograph). Moreover, the density | concentration of the water | moisture content in the dehumidifier exit was 25-30%.
[0045]
Example 2
As the adsorbent, synthetic zeolite, polymer compound (styrene polymer), fluorine powder, and fluorinated graphite were used, respectively. Other conditions were the same as in the present invention (A) in Example 1, 15, 40, and 100. The contact angle after time was measured. The results are shown in Table 1.
[0046]
[Table 1]

[0047]
Example 3
(The NO _x and SO _x 10 to 50 ppm containing) air in the clean room was acid cleaned using nitric acid and sulfuric acid from to remove moisture and particulate and HC by the apparatus shown in FIG. The wafer was exposed to the clean air thus obtained, and the contact angle was measured. Further, the fine particle concentration and the non-methane HC concentration were measured at the outlet of the gas preparation device according to the present invention. Furthermore, the water concentration at the outlet of the dehumidifier was also measured. Furthermore, the contact angle was also measured when the wafer was exposed to air before processing in a comparative apparatus and a clean room.
[0048]
Moisture concentration in clean room before processing test conditions: 40-60%
Fine particle concentration in clean room before treatment: class 10,000
Non-methane HC concentration in clean room before treatment: 0.82 ppm
Dehumidifier: Electronic dehumidifier (Peltier effect method) (manufactured by Shinei Sangyo Co., Ltd.)
Dust removal filter: ULPA (manufactured by Nippon Pole Co., Ltd., Gas Clean Filter SGLF6101)
Adsorbent: (1) Silica gel (for HC adsorption) (medium grain, SV: 1000 h ⁻¹ ) (Wako Pure Chemical Industries, Ltd.)
(2) Activated carbon impregnated with alkali (for NO _x and SO _x adsorption, SV: 1000 h ⁻¹ ) (manufactured by Tsurumi Coal) mounted on the downstream side of the silica gel Contact angle measuring device: Kyowa Interface Science Co., Ltd. 3) CA-D contact angle meter moisture measuring device: Electronic humidity sensor The relationship between the exposure time of the wafer to the air and the measured contact angle θ is shown in FIG. In FIG. 3, the present invention (F) (using a dehumidifier, a dust filter, and an adsorbent (2)) is indicated by a white circle -O-, and the dehumidifier is removed from the present invention (F) for comparison. The thing (G) is indicated by a black and white circle, and the thing (H) of the present invention (using a dehumidifier, a dust filter, and an adsorbent (1)) is indicated by a white square-□-. Further, as a comparison, those exposed to air before treatment in a clean room (I) are indicated by black circles-●-.
[0049]
The fine particle concentration at the outlet of the apparatuses (F) and (H) of the present invention was class 10 or less, and the concentration of non-methane HC was 0.1 ppm or less. The concentration of water at the outlet of the dehumidifier was 30 to 35%.
[0050]
Example 4
Water, fine particles, and HC were removed from the air in the clean room by the apparatus shown in FIG. 1 (however, the dust filter and adsorbent used below were used). The glass substrate was exposed to the purified air thus obtained, and the contact angle was measured. Further, the fine particle concentration and the non-methane HC concentration were measured at the outlet of the gas preparation device according to the present invention. Furthermore, the water concentration at the outlet of the dehumidifier was also measured. The contact angle was also measured when the dehumidifier was removed from the apparatus shown in FIG. 1 and when the glass substrate was exposed to air before treatment in a clean room.
[0051]
Moisture concentration in clean room before processing test conditions: 40-60%
Fine particle concentration in clean room before treatment: class 10,000
Non-methane HC concentration in clean room before treatment: 0.64 ppm
Dehumidifier: Electronic dehumidifier (Peltier effect method) (manufactured by Shinei Sangyo Co., Ltd.)
HC adsorbent: Silica gel (medium grain, SV: 1000 h ⁻¹ ) (manufactured by Wako Pure Chemical Industries, Ltd.) and fibrous borosilicate glass on the downstream side of this silica gel were formed into a filter shape using tetrafluoride resin as a binder. Dust filter equipped with a thing (SV: 10000h ^-1 ): A filter formed from the above fibrous borosilicate glass. Combined contact angle measuring device: CA-D type contact angle, manufactured by Kyowa Interface Science Co., Ltd. Moisture analyzer: Electronic humidity sensor Pretreatment of glass substrate: After cleaning with detergent and alcohol, the relationship between exposure time of glass substrate to ultraviolet irradiation air and measured contact angle θ under O ₃ generation is shown in FIG. Shown in In FIG. 4, the present invention (J) (dehumidifier, dust filter, HC adsorbent used) is indicated by white circles, and for comparison, the dehumidifier is removed from the present invention (J) ( K) is indicated by black and white circles. Further, as a comparison, those exposed to air before treatment in a clean room (L) are indicated by black circles-●-.
[0052]
The fine particle concentration at the outlet of the apparatus (J) of the present invention was class 10 or less, and the concentration of non-methane HC was 0.1 ppm or less. Moreover, the density | concentration of the water | moisture content in the dehumidifier exit was 25-30%.
[0053]
【The invention's effect】
The present invention has the following effects.
A clean gas is obtained by removing particulates in the gas and adsorbing and / or absorbing hydrocarbons by the method of the present invention. When this cleaning gas is exposed on a substrate or substrate such as a semiconductor or liquid crystal, contamination of the surface of the substrate or substrate is prevented.
[0054]
When the concentration of gaseous harmful components such as NO _x and SO _x other than hydrocarbons in the gas to be treated is high, a method for removing these harmful components (for example, the method already proposed by the present inventor) is appropriately selected, By combining it with the hydrocarbon adsorbent and / or absorbent according to the present invention, contamination is more effectively prevented.
[0055]
Furthermore, when removing hydrocarbons, the air to be treated is dehumidified and the water content is kept below a certain concentration, so that the hydrocarbon removal performance by the adsorbent is stably maintained over a long period of time. Thereby, the replacement frequency of the adsorbent is reduced, and the practicality is improved.
[Brief description of the drawings]
FIG. 1 shows an apparatus of the present invention, which is an example applied to purification of supply air for an air knife in a semiconductor manufacturing factory.
FIG. 2 is a graph showing the relationship between the exposure time of a glass substrate or wafer to air and the measured contact angle θ.
FIG. 3 is a graph showing the relationship between the exposure time of a glass substrate or wafer to air and the measured contact angle θ.
FIG. 4 is a graph showing the relationship between the exposure time of a glass substrate or wafer to air and the measured contact angle θ.

Claims (33)

  A method for adjusting a clean gas from a gas in a clean room, wherein the gas in the clean room is passed through a dehumidifying means so that the relative humidity is 50% (RH) or less, followed by an adsorbing means and / or absorbing means, and a dust removing means To adjust a clean gas having a non-methane hydrocarbon concentration of 0.2 ppm or less. The method according to claim 1 , wherein the dehumidifying means is a cooling type, an adsorption type, an absorption type, a compression type, a membrane separation type, or a combination thereof. The method according to claim 2 , wherein the dehumidifying means comprises silica gel or zeolite. The method according to any one of claims 1 to 3 , wherein the gas to be treated is passed through a preliminary dust removing means disposed upstream of the dehumidifying means before passing the gas to be treated through the dehumidifying means. The method according to claim 1 , wherein a gas to be treated is passed through the adsorption means and / or absorption means at a space velocity of 20000 h ⁻¹ or less. The method according to any one of claims 1 to 5 , wherein the gas to be treated is passed through the dehumidifying means, then passed through the adsorption means and / or the absorbing means, and then passed through the dust removing means. The method according to any one of claims 1 to 6 , wherein the fine particle concentration in the clean gas is set to class 10 or less. The method according to any one of claims 1 to 7 , wherein the dust removing means comprises at least one of a HEPA filter, a ULPA filter, and an electrostatic filter. The method according to any one of claims 1 to 8 , wherein the adsorption means and / or the absorption means are composed of at least one of activated carbon, silica gel, synthetic zeolite, molecular sieve, polymer compound, glass, fluorine compound and metal. The method according to claim 1 , wherein the relative humidity of the gas is 30% (RH) or less by the dehumidifying means.   A device for adjusting a clean gas having a non-methane hydrocarbon concentration of 0.2 ppm or less from the gas in the clean room, passing through the gas in the clean room, the dehumidifying means for making the relative humidity 50% (RH) or less, and the dehumidifying means An apparatus comprising an adsorbing means and / or an absorbing means for treating the generated gas, and a dust removing means. The apparatus according to claim 11 , wherein the dehumidifying means is a cooling type, an adsorption type, an absorption type, a compression type, a membrane separation type, or a combination thereof. The apparatus according to claim 12 , wherein the dehumidifying means is composed of silica gel or zeolite. The apparatus in any one of Claims 11-13 further equipped with the preliminary | backup dust removal means arrange | positioned upstream of a dehumidification means. The apparatus according to any one of claims 11 to 14 , wherein a space velocity of a gas passing through the adsorption unit and / or the absorption unit is 20000 h ^-1 or less. The apparatus according to any one of claims 11 to 15 , wherein at least one of the dehumidifying means is arranged downstream of the adsorption means and / or the absorption means. The apparatus according to any one of claims 11 to 16 , wherein a concentration of fine particles in the clean gas is class 10 or less. The apparatus according to any one of claims 11 to 17 , wherein the dust removing means includes at least one of a HEPA filter, a ULPA filter, and an electrostatic filter. The apparatus according to any one of claims 11 to 18 , wherein the adsorption means and / or the absorption means are composed of at least one of activated carbon, silica gel, synthetic zeolite, molecular sieve, polymer compound, glass, fluorine compound, and metal. The apparatus according to claim 11, wherein the relative humidity of the gas is set to 30% (RH) or less by the dehumidifying means.   A method of adjusting a clean gas from a gas having a relative humidity of 50% (RH) or less used in a clean room, wherein the gas having a relative humidity of 50% (RH) or less used in the clean room is adsorbed and / or absorbed. And a non-methane hydrocarbon concentration in the gas of 0.2 ppm or less through the dust removing means. The method according to claim 21 , wherein a gas to be treated is passed through the adsorption means and / or absorption means at a space velocity of 20000 h ^-1 or less. The method according to claim 21 or 22 , wherein the gas to be treated is passed through an adsorbing means and / or an absorbing means and then passed through a dust removing means. The method according to any one of claims 21 to 23 , wherein the fine particle concentration in the clean gas is set to class 10 or less. The method according to any one of claims 21 to 24 , wherein the dust removing means comprises at least one of a HEPA filter, a ULPA filter, and an electrostatic filter. The method according to any one of claims 21 to 25 , wherein the adsorption means and / or absorption means is composed of at least one of activated carbon, silica gel, synthetic zeolite, molecular sieve, polymer compound, glass, fluorine compound and metal. 27. The method according to any one of claims 21 to 26 , wherein a relative humidity of the gas to be treated is 30% (RH) or less.   An apparatus for adjusting a clean gas having a non-methane hydrocarbon concentration of 0.2 ppm or less from a gas having a relative humidity of 50% (RH) or less used in a clean room, and having a relative humidity of 50% (RH) or less used in a clean room An apparatus comprising an adsorbing means and / or an absorbing means for passing a gas, and a dust removing means. The apparatus according to claim 28 , wherein the space velocity of the gas passing through the adsorption means and / or the absorption means is 20000 h ^-1 or less. 30. The apparatus according to claim 28 or 29 , wherein the fine particle concentration in the clean gas is class 10 or less. The apparatus according to any one of claims 28 to 30 , wherein the dust removing means is composed of at least one of a HEPA filter, a ULPA filter, and an electrostatic filter. The apparatus according to any one of claims 28 to 31 , wherein the adsorption means and / or the absorption means are composed of at least one of activated carbon, silica gel, synthetic zeolite, molecular sieve, polymer compound, glass, fluorine compound, and metal. The apparatus according to any one of claims 28 to 32 , wherein the relative humidity of the gas to be treated is 30% (RH) or less.

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