JP3981386B2 - Method and apparatus for preventing contamination of substrate or substrate surface - Google Patents

Description

Detailed Description 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.

  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.

The prior art will be described below with reference to an example of clean air in a semiconductor manufacturing factory.
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.

  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 on 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.

  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.

On the other hand, as a method for removing HC, which is a gaseous pollutant, a combustion decomposition method, an O ₃ decomposition method, and the like are known. However, these methods are ineffective in removing extremely low concentrations of HC contained in the air introduced into the clean room.

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.

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 base material or the substrate surface (Patent Document). 1 and Patent Document 2). Although these methods and apparatuses are effective depending on the application field, further improvement is required to further increase the practicality.
Japanese Patent Application No. 3-341802 (Japanese Patent Application Laid-Open No. 05-157284) Japanese Patent Application No. 4-180538 (Japanese Patent Laid-Open No. 06-0003224)

  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.

  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.

  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.

  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.

  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.

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.
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 / 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 .

  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.

  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.

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.

  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).

  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.

  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.

  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.

  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.

  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.

  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.

  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 substance such as silica gel or a fluorine compound is used as the adsorbent.

  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).

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.

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 ).

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 substrate surface and increase the contact angle are (1) noxious gases such as SO _x , NO _x , HCl, NH ₃ , (2) fine particles, (3) HC, As a result of the study by the present inventors, the contact angle is determined in normal air (in the normal atmosphere in a clean room) or in N ₂ used 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 contact angle at a normal concentration level in air. Therefore, the effect is obtained by dust removal and removal of HC. However, _if harmful gases such as SOx are generated in or around the clean room and their concentrations are high, they are affected by these gas components, and even if these concentrations are low enough not to normally affect 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: Japanese Patent Application Laid-Open No. 3-226686) that has been proposed by the present inventor to irradiate a harmful gas with ultraviolet rays and / or radiation to form fine particles of the gas. Kaihei 4-243517) is preferably used in appropriate combination. 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.

  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. .

  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).

  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.

  The air 2 in the clean room 1 containing moisture (RH 40 to 60%), fine particles (class 10000), and extremely low concentration 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.

  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.

  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.

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.
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.

  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.

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.

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 (that is, only the dust filter is used), and the dehumidifier and the dust filter removed (that is, only the HC adsorbent is 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.

Test conditions Water concentration in clean room before treatment: 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 instrument: Kyowa Interface Science Co., Ltd., CA-D type contact angle meter Moisture measuring instrument: Electronic humidity sensor Pretreatment of glass substrate: Washed with detergent and alcohol, then irradiated with ultraviolet rays under generation of O ₃ to air 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.

  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%.

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.

Example 3
Moisture, fine particles, and HC were removed from the air in a clean room (containing 10 to 50 ppm of NO _x and SO _x ) that was acid-washed using nitric acid and sulfuric acid, using 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.

Test conditions Water concentration in clean room before treatment: 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) attached to 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-●-.

  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%.

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.

Test conditions Water concentration in clean room before treatment: 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. Wearing thing (SV: 10000h ^-1 ) Dust removal filter: The above-mentioned fibrous borosilicate glass is formed into a filter shape. Also used as a contact angle measuring instrument: Kyowa Interface Science Co., Ltd., CA-D contact angle Meter Moisture meter: Electronic humidity sensor Pretreatment of glass substrate: Washed with detergent and alcohol, then irradiated with UV light in the presence of O ₃ Figure 4 shows the relationship between exposure time of glass substrate to air and measured contact angle θ 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-●-.

  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%.

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.

Further, 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.

  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.

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 the 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 the 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 the glass substrate or wafer to air and the measured contact angle θ.

Claims (24)

housing;
A gas supply channel connected to the housing;
Adsorption means and / or absorption means selected from silica gel or fluorine compounds for removing non-methane hydrocarbons disposed in the gas supply flow path; and
A dust filter comprising a fibrous glass disposed on the downstream side of the adsorbing means and / or absorbing means in the form of a filter using a fluorine compound resin as a binder ;
A substrate or substrate cleaning apparatus comprising: The said dust removal filter is a washing | cleaning apparatus of Claim 1 which is a dust removal filter which makes a filter shape by using fibrous borosilicate glass as a binder with tetrafluoride resin. Furthermore, the washing | cleaning apparatus of Claim 1 or 2 containing the base material which should be wash | cleaned arrange | positioned in the housing. Furthermore, the dehumidification means for reducing the water density | concentration in the to-be-processed gas arrange | positioned upstream of the said adsorption means and / or absorption means to 50% (RH) or less is any one of Claims 1-3 . cleaning apparatus according to. The cleaning apparatus according to claim 4 , wherein the dehumidifying means is a cooling type, an adsorption type, an absorption type, a compression type, a membrane separation, or a combination thereof. The cleaning device according to claim 5 , wherein the dehumidifying means is made of silica gel or zeolite. The cleaning apparatus according to any one of claims 1 to 6, wherein the non-methane hydrocarbon concentration in the gas is reduced to 0.2 ppm or less by the adsorption means and / or the absorption means. The cleaning apparatus according to any one of claims 1 to 7, wherein a space velocity of a gas passing through the adsorption unit and / or the absorption unit is 20000 h ^-1 or less. The cleaning apparatus according to any one of claims 1 to 8, wherein the gas to be supplied is air, nitrogen gas, argon gas, or a mixture thereof. The cleaning device according to any one of claims 1 to 9 , wherein the space in the housing is a space under atmospheric pressure, a space under reduced pressure, or a vacuum space. The cleaning according to any one of claims 1 to 10, wherein a dust removing means comprising at least one of a HEPA filter, a ULPA filter and an electrostatic filter is further provided upstream of the adsorption means and / or the absorption means. apparatus. Furthermore, less than cleaning apparatus according to claim 1 or 2, cleaning apparatus according to claim 1 or 2 having other apparatus for cleaning the placed substrates or substrate within the housing. Further, the cleaning device according to any one of claims 1 to 12 comprising means for protecting exposed to clean gas which has been treated substrate or the surface of the substrate the substrate or the surface of the substrate from contamination. A method for cleaning a substrate or substrate disposed in a housing, comprising:
Passing the gas supplied to the housing through adsorption means and / or absorption means selected from silica gel or fluorine compounds to reduce the concentration of non-methane hydrocarbons therein;
The treated gas is passed through a dust removal filter made of fiber glass and a fluorine compound resin as a binder to form a filter, and fine particles contained in the gas are removed;
Introducing gas into the housing in which the substrate or substrate is located;
A method comprising the steps. The cleaning method according to claim 14, wherein the dust removal filter is a dust removal filter in which fibrous borosilicate glass is formed into a filter shape using tetrafluororesin as a binder. The method according to claim 14 or 15 , wherein the concentration of fine particles in the gas is set to class 10 or less by the adsorption means and / or the absorption means and the dust filter . The method according to any one of claims 14 to 16, wherein the concentration of non-methane hydrocarbon in the gas is 0.2 ppm or less by the adsorption means and / or absorption means. The method according to any one of claims 14 to 17, wherein the gas to be supplied is air, nitrogen gas, argon gas or a mixture thereof. The method according to any one of claims 14 to 18 , wherein the space in the housing is a space under atmospheric pressure, a space under reduced pressure, or a vacuum space. In addition,
The supplied gas is passed through a dehumidifying means before passing through the adsorbing means and / or absorbing means to reduce the moisture concentration in the gas to 50% (RH) or less;
The method according to any one of claims 14 to 19 , comprising a step.   The method according to claim 20, wherein the dehumidifying means is a cooling type, an adsorption type, an absorption type, a compression type, a membrane separation, or a combination thereof.   The method according to claim 21, wherein the dehumidifying means comprises silica gel or zeolite. The method according to any one of claims 14 to 22, wherein the space velocity of the gas passing through the adsorption means and / or absorption means is 20000 h ^-1 or less. 24. A method according to any of claims 14 to 23, further comprising the step of exposing the surface of the substrate or substrate to a treated clean gas to protect the surface of the substrate or substrate from contamination.