JPWO2013137300A1 - Silanol compound removing agent, silanol compound removing method, chemical filter and exposure apparatus - Google Patents

Abstract

A silanol compound removing agent characterized by being an activated carbon having an oxygen-containing functional group, wherein the amount of the oxygen-containing functional group per 1 g of the activated carbon is 0.5 mmol / g or more. ADVANTAGE OF THE INVENTION According to this invention, the silanol compound removal agent with a high removal effect of a silanol compound can be provided.

Description

  The present invention relates to a silanol compound removing agent for removing a silanol compound such as removal of a silanol compound in air to be treated containing the silanol compound.

  In industries such as semiconductors and liquid crystals, control of air in clean rooms and product surfaces is important to ensure product yield, quality, and reliability. In particular, in the semiconductor industry field, circuit patterns are miniaturized as products are highly integrated, so that the exposure wavelength has become shorter in the exposure process used for semiconductor manufacturing. At present, a KrF excimer laser having a wavelength of 248 nm and an ArF excimer laser having a wavelength of 193 nm are used as a light source.

  In semiconductor manufacturing, when a hydroxyl group is present on the wafer surface, the resist is repelled. Therefore, as a wafer processing process, hexamethyldisilazane (HMDS) is used to remove the hydroxyl group of the wafer before applying the photoresist and increase the hydrophobicity. ) Is used. When this HMDS is hydrolyzed, trimethylsilanol is produced. And in the said exposure process, trimethylsilanol raise | generates photochemical reaction with light with a short wavelength with high energy, adheres to the exposure lens of an exposure apparatus, causes a haze (cloudiness), and causes exposure trouble.

  From such a background, Patent Document 1 (Japanese Patent Laid-Open No. 2009-295765) discloses that silanols are brought into contact with a fibrous inorganic compound having a hydroxyl group, and the silanols are chemically bonded to the fibrous inorganic compound. A method for purifying a substrate to be collected and removed is disclosed.

  Patent Document 2 (Japanese Patent Application Laid-Open No. 2011-166085) includes a large number of adsorbents composed of a porous body, and at least a part of the large number of adsorbents includes a metal catalyst (platinum or palladium). A supported chemical filter is disclosed. The chemical filter employs a method in which a silanol compound is dimerized in a filter portion on which a metal catalyst is supported, and the dimer is adsorbed on a filter portion on which the metal catalyst is not supported.

  Patent Document 3 (Japanese Patent Application Laid-Open No. 2012-30164) describes a dehumidifying means that dehumidifies air containing a silanol compound to a relative humidity of 33% or less, and air dehumidified by the dehumidifying means. An air purification system comprising a chemical filter for filtering and removing the silanol compound is disclosed.

JP 2009-295765 A (Claims) JP 2011-166085 A (Claims) JP 2012-30164 A (Claims)

  However, in Cited Document 1, a mechanism for maintaining the surface temperature of the inorganic fiber compound at 70 to 300 ° C. is necessary, and it is practical to mount it on an exposure apparatus or the like in which the temperature and humidity are extremely precisely controlled. It will also be expensive.

  Further, in Cited Document 2, an expensive metal catalyst is used, a part on which the metal catalyst is supported, and a part for adsorbing the dimer of the silanol compound are required, so that the filter layer becomes thick. It is not economical.

  Moreover, since Cited Document 3 requires a dehumidifying device for performing dehumidification, the cost increases.

  Therefore, the subject of this invention is providing the silanol compound removal agent with a high removal effect of the silanol compound, especially the removal effect of the silanol compound in to-be-processed air. Moreover, the subject of this invention is providing the removal method of the silanol compound with the high removal effect of the silanol compound in to-be-processed air.

  As a result of intensive studies to solve the above-described problems in the prior art, the present inventors have made contact with a silanol compound, particularly trimethylsilanol, by contacting activated carbon into which an oxygen-containing functional group has been introduced. The silanol compound can be dimerized by the action of the functional group, and by dimerizing the silanol compound, it can be easily adsorbed on the activated carbon, and the amount of oxygen-containing functional group in the activated carbon is in a specific range. As a result, it has been found that the removal effect of silanol compounds, particularly trimethylsilanol compounds, is increased, and the present invention has been completed.

  That is, the present invention (1) is activated carbon having an oxygen-containing functional group, and the amount of the oxygen-containing functional group per 1 g of the activated carbon having the oxygen-containing functional group is 0.5 mmol / g or more. A silanol compound removing agent is provided.

  Moreover, this invention (2) produced | generated by making the to-be-processed air containing a silanol compound contact the activated carbon which has an oxygen-containing functional group of 0.5 mmol / g or more per gram, and dimerizing the silanol compound. Provided is a method for removing a silanol compound, characterized in that the silanol compound in the air to be treated is removed by adsorbing the dimer of the silanol compound to activated carbon having the oxygen-containing functional group. is there.

  In addition, the present invention (3) carries out the silanol compound removal method of the present invention (2), characterized in that activated carbon having an oxygen-containing functional group of 0.5 mmol / g or more per gram is used. A chemical filter is provided.

  Moreover, this invention (4) provides the exposure apparatus characterized by having the chemical filter of this invention (3).

  ADVANTAGE OF THE INVENTION According to this invention, the removal effect of a silanol compound, especially the silanol compound removal agent with a high removal effect of the silanol compound in to-be-processed air can be provided. Moreover, according to this invention, the removal method of the silanol compound with the high removal effect of the silanol compound in to-be-processed air can be provided. Moreover, according to this invention, the chemical filter with the high removal effect of the silanol compound in to-be-processed air can be provided. Further, according to the present invention, it is possible to provide an exposure apparatus with few exposure obstacles due to adhesion of trimethylsilanol to the exposure lens.

It is a figure which shows the trimethylsilanol removal test apparatus used in the Example. It is a graph which shows the time-dependent change of the trimethylsilanol removal rate of an Example and a comparative example.

  The silanol compound removing agent of the present invention is activated carbon having an oxygen-containing functional group, and the amount of the oxygen-containing functional group per 1 g of the activated carbon having the oxygen-containing functional group is 0.5 mmol / g or more. Silanol compound remover.

  The silanol compound removing agent of the present invention is activated carbon having an oxygen-containing functional group, that is, activated carbon into which an oxygen-containing functional group has been introduced. That is, the activated carbon having an oxygen-containing functional group is activated carbon in which an oxygen-containing functional group is bonded to a carbon atom of the activated carbon. In other words, the silanol compound removing agent of the present invention is activated carbon that has been subjected to oxidation treatment, and activated carbon into which an oxygen-containing functional group has been introduced by oxidation treatment.

  Examples of the oxygen-containing functional group include a carbonyl group, a hydroxyl group, a lactone group, a carboxyl group, a quinone group, and a carboxylic anhydride group. The activated carbon having an oxygen-containing functional group preferably has at least one or more of a carbonyl group, a hydroxyl group, a lactone group and a carboxyl group as the oxygen-containing functional group, and at least a carbonyl group, a hydroxyl group It is particularly preferable to have a lactone group and a carboxyl group.

  The amount of the oxygen-containing functional group per 1 g of the activated carbon having an oxygen-containing functional group is 0.5 mmol / g or more, preferably 0.8 to 3.0 mmol / g, particularly preferably 1.0 to 2.5 mmol / g. It is. When the amount of the oxygen-containing functional group per 1 g of the activated carbon having the oxygen-containing functional group is within the above range, the effect of removing the silanol compound is enhanced.

In addition, the amount of oxygen-containing functional groups per 1 g of activated carbon having oxygen-containing functional groups and the amount of each functional group are measured as follows. First, activated carbon having an oxygen-containing functional group is vacuum-dried for 8 to 10 hours in a constant temperature dryer adjusted to 115 ° C., and then allowed to cool in a desiccator containing silica gel as a desiccant. Next, four 50 ml stoppered Erlenmeyer flasks (A, B, C, D) are prepared, and 1 g of cooled activated carbon is accurately weighed to 0.1 mg in each Erlenmeyer flask. Next, an N / 10 sodium hydrogen carbonate aqueous solution was added to the Erlenmeyer flask (D), an N / 10 sodium carbonate aqueous solution was added to the Erlenmeyer flask (C), an N / 10 sodium hydroxide aqueous solution was added to the Erlenmeyer flask (B), and an Erlenmeyer flask (A ) 25 ml of N / 10 sodium ethoxide ethanol solution is added to the solution and shaken at 160 rpm at 25 ° C. for 24 hours. After shaking, the supernatant and precipitate are separated by centrifugation, and 10 ml of the supernatant is accurately weighed into a 20 ml beaker and titrated with N / 10 hydrochloric acid until the pH is 4 using a pH meter. Next, the consumption of each base per gram of activated carbon is calculated from the hydrochloric acid titration amount according to the following formula.
Base consumption (mmol / g) = (0.1 × (10-HCl titration) × 25) / 10
As a result of titration, the consumption of sodium bicarbonate was D (mmol / g), the consumption of sodium carbonate was C (mmol / g), the consumption of aqueous sodium hydroxide was B (mmol / g), and the sodium ethoxide When the consumption was A (mmol / g), the amount of oxygen-containing functional groups per gram of activated carbon was “A (mmol / g)”, and the amount of carbonyl groups was “A-B (mmol / g). g) ", the amount of hydroxyl groups is" BC (mmol / g) ", the amount of lactone groups is" CD (mmol / g) ", and the amount of carboxyl groups is" D (mmol / g) ". .

  The substance removed by the silanol compound removing agent of the present invention is a silanol compound contained in the air to be treated. A silanol compound is a compound having a silanol group (—Si—OH). As the silanol compound, a silanol compound having a molecular weight of 300 or less is preferable, and a silanol compound having a molecular weight of 200 or less is particularly preferable. More preferably, examples of the silanol compound include trimethylsilanol and triethylsilanol. And the silanol compound removing agent of this invention has a remarkable effect especially when to-be-processed air contains a trimethylsilanol.

BET specific surface area of the activated carbon with oxygen-containing functional groups is preferably 500~2000m ² / g, particularly preferably 800~1700m ² / g. When the BET specific surface area of the activated carbon having an oxygen-containing functional group is in the above range, the silanol compound removal effect is enhanced.

The average pore diameter of the activated carbon having an oxygen-containing functional group is preferably 0.4 to 3.0 nm, particularly preferably 0.6 to 2.5 nm. The total pore volume of the activated carbon having an oxygen-containing functional group is preferably 0.30 to 2.00 cm ³ / g, particularly preferably 0.40 to 1.50 cm ³ / g. When the average pore diameter or total pore volume of the activated carbon having an oxygen-containing functional group is in the above range, the removal effect of the silanol compound is enhanced.

  Examples of a method for producing activated carbon having an oxygen-containing functional group include a method of oxidizing activated carbon in a gas phase or a liquid phase.

Although it does not restrict | limit especially as activated carbon used as the raw material of manufacture of the activated carbon which has an oxygen-containing functional group, A coconut shell type | system | group activated carbon, a wood charcoal type activated carbon, a pitch type activated carbon, a phenol resin type activated carbon etc. are mentioned. The BET specific surface area of the raw material activated carbon is preferably 600 to 2000 m ² / g, particularly preferably 900 to 1800 m ² / g. The average pore diameter of the raw material activated carbon is preferably 0.4 to 3.0 nm, particularly preferably 0.6 to 2.5 nm. The total pore volume of the raw material activated carbon is preferably 0.30 to 2.00 cm ³ / g, particularly preferably 0.40 to 1.50 cm ³ / g.

  As a method of oxidizing activated carbon in the gas phase, a method of oxidizing activated carbon with ozone gas, a method of oxidizing with chlorine gas, a method of air oxidation by heating in air, a combination of oxygen treatment and nitrogen oxide treatment, oxygen Examples thereof include low-temperature plasma treatment with gas or air.

  In addition, as a method of oxidizing activated carbon in the liquid phase, activated carbon is converted into ozone aqueous solution, nitric acid aqueous solution, hydrogen peroxide aqueous solution, sulfuric acid solution, chloric acid solution, iodic acid solution, hypochlorous acid solution, bromine aqueous solution, permanganic acid. The method of immersing in a potassium solution etc. is mentioned. After the activated carbon is oxidized in the liquid phase, the oxidized activated carbon is sufficiently washed with pure water and dried at about 80 to 120 ° C.

  The oxidation conditions of the activated carbon are selected as appropriate, but the condition that the amount of oxygen-containing functional groups per 1 g of activated carbon is 0.5 mmol / g or more, preferably 0.8 to 3.0 mmol / g, particularly Preferably, a condition of 1.0 to 2.5 mmol / g is selected.

  Then, by oxidizing the activated carbon, a part of the carbon of the activated carbon is oxidized and converted to an oxygen-containing functional group, and activated carbon having an oxygen-containing functional group is obtained.

  The silanol compound removing agent of the present invention is used for removing a silanol compound such as removal of a silanol compound in air to be treated containing the silanol compound.

Since the silanol compound removing agent of the present invention is activated carbon having an oxygen-containing functional group, the silanol compound and the oxygen-containing functional group come into contact with the oxygen-containing functional group, for example, by contact with the air to be treated containing the silanol compound. Then, as shown in the following formula (1), the unshared electron pair of the oxygen atom of the oxygen-containing functional group in the activated carbon having an oxygen-containing functional group is bonded to the hydrogen atom of the silanol group in the silanol compound, It is considered that two silanol compounds in which a hydrogen atom of a silanol group is bonded to an unshared electron pair of an oxygen atom of an oxygen-containing functional group present in the vicinity undergoes dehydration condensation to dimerize. The dimerization reaction is “2R ₃ SiOH → R ₃ SiOSiR ₃ + H ₂ O”.
Formula (1):

  The present inventors have found that dimerization of the silanol compound occurs even at a low temperature of 5 to 40 ° C., preferably 10 to 30 ° C., due to the action of the oxygen-containing functional group introduced into the activated carbon, and the silanol compound is dimerized. As a result, the molecular weight of the object to be removed can be increased, so that it can be easily adsorbed on the activated carbon. And the amount of the oxygen-containing functional group per 1 g of the activated carbon having an oxygen-containing functional group is 0.5 mmol / g or more, preferably 0.8 to 3.0 mmol / g, particularly preferably 1.0 to 2.5 mmol. It was found that the effect of removing the silanol compound is enhanced by setting the amount to / g. Therefore, according to the silanol compound removing agent of the present invention, even low molecular weight silanol compounds such as trimethylsilanol, which have been conventionally considered difficult to adsorb and remove with activated carbon due to the low molecular weight, are adsorbed on activated carbon. Can be removed. Further, according to the silanol compound removing agent of the present invention, it is possible to remove the silanol compound such as removal of the silanol compound in the air to be treated at a low temperature of 5 to 40 ° C., preferably 10 to 30 ° C.

  In particular, the silanol compound removing agent of the present invention exhibits an excellent silanol compound removing effect in removing silanol compounds in the air to be treated containing a silanol compound having a relative humidity of 45% or less. The lower limit of the relative humidity is not particularly limited, but the relative humidity is preferably 15% or more, particularly preferably 20% or more, and further preferably 25% or more.

  Examples of the method for removing the silanol compound in the air to be treated using the silanol compound removing agent of the present invention include a method of bringing the silanol compound removing agent of the present invention into contact with the air to be treated containing the silanol compound.

  The air to be treated that is treated with the silanol compound removing agent of the present invention is not particularly limited. For example, silanol such as air in an optical system installation space of an exposure apparatus for semiconductor production, air in a clean room for semiconductor production, etc. Air containing a compound. The silanol compound contained in the air to be treated is a compound having a silanol group (—Si—OH), and examples thereof include trimethylsilanol and triethylsilanol. And the silanol compound removing agent of this invention has a remarkable effect especially when to-be-processed air contains a trimethylsilanol. The content of the silanol compound in the air to be treated is not particularly limited. For example, in the case of air in an optical system installation space of an exposure apparatus for manufacturing a semiconductor, it is usually 0.3 to 8.0 ppb.

  The silanol compound removing agent of the present invention is preferably used as a silanol compound removing agent for carrying out the silanol compound removing method of the present invention described below. That is, the silanol compound removal method of the present invention is such that the silanol compound remover of the present invention is brought into contact with the treated air containing the silanol compound to dimerize the silanol compound, and the dimer of the generated silanol compound is dimerized. A silanol compound removing method comprising removing a silanol compound in the air to be treated by adsorbing a body to activated carbon having the oxygen-containing functional group.

  In the method for removing a silanol compound of the present invention, activated carbon having an oxygen-containing functional group of 0.5 mmol / g or more per 1 g is brought into contact with the air to be treated containing the silanol compound to dimerize the silanol compound. The silanol compound removal method is characterized in that the silanol compound in the air to be treated is removed by adsorbing the dimer of the silanol compound to the activated carbon having the oxygen-containing functional group.

  The activated carbon having an oxygen-containing functional group according to the method for removing a silanol compound of the present invention is the same as the activated carbon having an oxygen-containing functional group according to the silanol compound removing agent of the present invention.

  In the silanol compound removal method of the present invention, the activated carbon having an oxygen-containing functional group is brought into contact with the air to be treated containing the silanol compound.

  The air to be treated is not particularly limited, but is air containing a silanol compound such as air in an optical system installation space of an exposure apparatus for semiconductor manufacture, air in a clean room for semiconductor manufacture, and the like.

  The silanol compound contained in the air to be treated is a compound having a silanol group (—Si—OH). As the silanol compound, a silanol compound having a molecular weight of 300 or less is preferable, and a silanol compound having a molecular weight of 200 or less is particularly preferable. More preferably, examples of the silanol compound include trimethylsilanol and triethylsilanol. And in the removal method of the silanol compound of this invention, when a to-be-processed air contains a trimethylsilanol, there exists a remarkable effect.

  The content of the silanol compound in the air to be treated is not particularly limited. For example, in the case of air in an optical system installation space of an exposure apparatus for manufacturing a semiconductor, it is usually 0.3 to 8.0 ppb.

  The method of bringing the air to be treated into contact with the activated carbon having an oxygen-containing functional group is not particularly limited. For example, the activated carbon having an oxygen-containing functional group is formed by filling activated carbon having an oxygen-containing functional group into a filling container. Examples thereof include a method of allowing the air to be treated to pass through the activated carbon layer, a method of supporting the activated carbon having an oxygen-containing functional group on a carrier, and allowing the air to be treated to pass through the carrier.

  The temperature at which the air to be treated is brought into contact with the activated carbon having an oxygen-containing functional group is 5 to 40 ° C, preferably 10 to 30 ° C.

  The supply amount of the air to be treated when the air to be treated is brought into contact with the activated carbon having the oxygen-containing functional group is appropriately selected depending on the content of the silanol compound in the air to be treated, the amount of the activated carbon having the oxygen-containing functional group, etc. Is done.

In the method for removing a silanol compound of the present invention, the activated carbon having an oxygen-containing functional group is brought into contact with the treated air containing the silanol compound to bring the activated carbon having an oxygen-containing functional group into contact with the activated carbon having the oxygen-containing functional group. The unshared electron pair of the oxygen atom of the oxygen-containing functional group and the hydrogen atom of the silanol group in the silanol compound are bonded to each other, and then to the unshared electron pair of the oxygen atom of the oxygen-containing functional group present in the vicinity Two silanol compounds to which the hydrogen atom of the silanol group is bonded are considered to undergo dehydration condensation and dimerization. The dimerization reaction is “2R ₃ SiOH → R ₃ SiOSiR ₃ + H ₂ O”.

  The present inventors have found that dimerization of the silanol compound occurs even at a low temperature of 5 to 40 ° C., preferably 10 to 30 ° C., due to the action of the oxygen-containing functional group introduced into the activated carbon, and the silanol compound is dimerized. Since the molecular weight of the object to be removed can be increased, it can be easily adsorbed on the activated carbon, and the amount of oxygen-containing functional groups in the activated carbon is within a specific range, thereby removing the silanol compound. Found to be higher. And the amount of the oxygen-containing functional group per 1 g of the activated carbon having an oxygen-containing functional group is 0.5 mmol / g or more, preferably 0.8 to 3.0 mmol / g, particularly preferably 1.0 to 2.5 mmol. It was found that the effect of removing the silanol compound is enhanced by setting the amount to / g. Therefore, according to the silanol compound removal method of the present invention, even low-molecular weight silanol compounds such as trimethylsilanol, which have been conventionally considered difficult to adsorb and remove with activated carbon due to its low molecular weight, are adsorbed on activated carbon. Can be removed. Moreover, according to the removal method of the silanol compound of this invention, the removal of the silanol compound in to-be-processed air can be performed at 5-40 degreeC, Preferably it is 10-30 degreeC low temperature.

  Activated carbon having an oxygen-containing functional group of 0.5 mmol / g or more per gram is an excellent silanol compound particularly in removing silanol compounds in air to be treated containing a silanol compound having a relative humidity of 45% or less. Demonstrate the removal effect. Therefore, in the method for removing a silanol compound of the present invention, the relative humidity of the air to be treated containing the silanol compound is preferably 45% or less. The lower limit of the relative humidity is not particularly limited, but the relative humidity is preferably 15% or more, particularly preferably 20% or more, and further preferably 25% or more. That is, in the method for removing a silanol compound of the present invention, the relative humidity of the air to be treated containing the silanol compound is preferably 15 to 45%, particularly preferably 20 to 45%, and further preferably 25 to 45%.

  The chemical filter of the present invention is a chemical filter for carrying out the method for removing a silanol compound of the present invention, and is activated carbon having an oxygen-containing functional group of 0.5 mmol / g or more per gram (silanol compound removing agent of the present invention). Activated carbon having an oxygen-containing functional group according to the method for removing a silanol compound of the present invention) is used.

  The activated carbon having an oxygen-containing functional group according to the chemical filter of the present invention is the same as the activated carbon having an oxygen-containing functional group according to the silanol compound removing agent of the present invention.

  Examples of the chemical filter of the present invention include a chemical filter in which activated carbon having an oxygen-containing functional group of 0.5 mmol / g or more per gram is filled in a gas-permeable filling container to form an activated carbon layer.

  The chemical filter of the present invention includes a chemical filter in which activated carbon having an oxygen-containing functional group of 0.5 mmol / g or more per 1 g is supported on a carrier.

  In the chemical filter of the present invention in which activated carbon having an oxygen-containing functional group is supported on the carrier, the carrier on which the activated carbon having an oxygen-containing functional group is supported is not particularly limited and is used as a carrier for a chemical filter. For example, an inorganic fibrous base material (paper) composed of inorganic fibers is formed into a honeycomb structure or a pleated structure, and an organic fibrous base material (paper) composed of organic fibers is honeycomb. Examples thereof include an organic fibrous carrier molded into a structure or a pleated structure. Among these, as the carrier, a pleated structure is preferable because it can increase the amount of activated carbon per unit volume and has a low pressure loss.

  In the chemical filter of the present invention in which activated carbon having oxygen-containing functional groups is supported on the carrier, the method for supporting activated carbon having oxygen-containing functional groups is not particularly limited. For example, in the chemical filter of the present invention in which activated carbon having an oxygen-containing functional group is supported on a carrier, the activated carbon having an oxygen-containing functional group may be supported on a carrier by using a binder, or an inorganic fiber Activated carbon having oxygen-containing functional groups may be supported by a sheet of quality or organic fiber so as to be supported.

  And, into the chemical filter of the present invention, air to be treated containing a silanol compound, for example, air in an optical system installation space of an exposure apparatus for manufacturing a semiconductor, air in a clean room for manufacturing a semiconductor, etc. Removal of the silanol compound of the present invention using the chemical filter of the present invention by passing the air to be treated into contact with the activated carbon having an oxygen-containing functional group supported on the carrier. The method can be carried out.

  As described above, the activated carbon having an oxygen-containing functional group of 0.5 mmol / g or more per gram, particularly in the removal of the silanol compound in the air to be treated containing a silanol compound having a relative humidity of 45% or less, Since the chemical filter of the present invention in which such activated carbon is used exhibits an excellent silanol compound removal effect, the removal of the silanol compound in the treated air containing the silanol compound having a relative humidity of 45% or less In, it has excellent silanol compound removal performance.

  The exposure apparatus of the present invention is an exposure apparatus having the chemical filter of the present invention.

  The chemical filter according to the exposure apparatus of the present invention is the same as the chemical filter of the present invention.

  The structure of the exposure apparatus of the present invention is not particularly limited, and may be any exposure apparatus that is usually used for semiconductor manufacturing.

  The exposure apparatus of the present invention is provided with an optical system installation space in which an optical system member and an exposure object are installed and can be shielded from external air. Further, the exposure apparatus of the present invention extracts the air in the optical system installation space and returns the air in the optical system installation space back to the optical system installation space and the air in the clean room in the optical system installation space. And an external air intake path for intake. In the exposure apparatus of the present invention, the chemical filter of the present invention is installed in each of the circulation path and the external air intake path.

  The exposure apparatus of the present invention includes a relay lens system, a condenser lens system, a projection optical system lens (hereinafter also referred to as an optical system member), and an exposure object installation portion. In the exposure apparatus of the present invention, the optical system member and the exposure object are installed in a small chamber that can be cut off from the outside air, so that the space of the installation part in which the optical system member and the exposure object are installed ( Hereinafter, it is also referred to as an optical system installation space.) Is cut off from outside air.

  In the exposure apparatus of the present invention, air in the optical system installation space is extracted and returned to the optical system installation space, and the air circulation path in the optical system installation space and the air in the clean room are taken into the optical system installation space. An external air intake path, and the chemical filter of the present invention is installed in each of the circulation path and the external air intake path. In the exposure apparatus of the present invention, the air in the optical system installation space extracted from the optical system installation space in the circulation path is extracted by passing through the chemical filter installed in the circulation path. In addition, silanol compounds in the air in the optical system installation space, particularly trimethylsilanol, are removed. The air from which silanol compounds such as trimethylsilanol have been removed is returned to the optical system installation space again. In the exposure apparatus of the present invention, in the external air intake path, the air taken in from the clean room passes through the chemical filter installed in the external air intake path, so that the air in the clean room taken in The silanol compound, especially trimethylsilanol, is removed. The air from which silanol compounds such as trimethylsilanol have been removed is supplied to the optical system installation space.

(Analysis method and evaluation method)
<Measurement method of oxygen-containing functional group amount>
The activated carbon to be measured was vacuum-dried for 8 to 10 hours in a constant temperature dryer adjusted to 115 ° C., and then allowed to cool in a desiccator containing silica gel as a desiccant. Next, four 50 ml stoppered Erlenmeyer flasks (A, B, C, D) were prepared, and 1 g of cooled activated carbon was accurately weighed to 0.1 mg in each Erlenmeyer flask. Next, an N / 10 sodium hydrogen carbonate aqueous solution was added to the Erlenmeyer flask (D), an N / 10 sodium carbonate aqueous solution was added to the Erlenmeyer flask (C), an N / 10 sodium hydroxide aqueous solution was added to the Erlenmeyer flask (B), and an Erlenmeyer flask (A ) 25 ml of N / 10 sodium ethoxide ethanol solution was added to the solution and shaken at 160 rpm at 25 ° C. for 24 hours. After shaking, the mixture was separated into a supernatant and a precipitate by centrifugation, and 10 ml of the supernatant was accurately weighed in a 20 ml beaker and titrated with N / 10 hydrochloric acid until the pH reached 4 using a pH meter. Next, the consumption of each base per gram of activated carbon was calculated from the hydrochloric acid titration amount by the following formula.
Base consumption (mmol / g) = (0.1 × (10-HCl titration) × 25) / 10
The consumption of sodium bicarbonate is D (mmol / g), the consumption of sodium carbonate is C (mmol / g), the consumption of aqueous sodium hydroxide is B (mmol / g), and the consumption of sodium ethoxide is A (Mmol / g), the oxygen-containing functional group amount per 1 g of activated carbon is “A (mmol / g)”, and the carbonyl group amount is “A-B (mmol / g)”. Is “BC (mmol / g)”, the amount of lactone group is “CD (mmol / g)”, and the amount of carboxyl group is “D (mmol / g)”.

<Trimethylsilanol removal test>
As shown in FIG. 1, a test sample having a thickness of 5 mm (length in the aeration direction of the air to be treated) is inserted in a hollow glass tube 2 having an inner diameter of 20 mm and a length of 300 mm by a support member 4. A layer (activated carbon layer) 3 was formed to produce a trimethylsilanol removal test apparatus 1.
Next, 150 ppb trimethylsilanol-containing air (temperature: 23 ° C., relative humidity: 45% (Example 1 and Comparative Example 1), 35% (Example 2 and Comparative Example 2), or 25% (Example 3 and Comparative Example) Example 3)) was supplied from the gas inlet 21 and discharged from the gas outlet 22, and the air to be treated was vented to the test sample layer 3 at a wind speed of 0.3 m / sec. Every time a predetermined time elapses, the trimethylsilanol-containing air on the gas inlet 21 side during ventilation and the trimethylsilanol-containing air on the gas outlet 22 side are collected by a dedicated analytical carbon-based adsorption tube, and the mass of the gas chromatograph Analysis was performed using an analyzer, and the concentration of trimethylsilanol in each collected air was analyzed. The trimethylsilanol removal rate for each elapsed time was determined by the following formula.
Trimethylsilanol removal rate (%) = ((trimethylsilanol concentration at the inlet side−trimethylsilanol concentration at the outlet side) / trimethylsilanol concentration at the inlet side) × 100

Example 1
Oxidation was performed by exposing 50 g of activated carbon a having an average particle size of crushed shape of 32/60 mesh (0.25 to 0.50 mm) and a specific surface area of 1500 m ² / g in a 1% ozone atmosphere for 8 hours. When the amount of oxygen-containing functional groups of the obtained activated carbon A having oxygen-containing functional groups was measured, the amount of oxygen-containing functional groups was 1.57 mmol / g, the amount of carbonyl groups was 0.35 mmol / g, and the amount of hydroxyl groups was 0.59 mmol. / G, the amount of lactone groups was 0.33 mmol / g, and the amount of carboxyl groups was 0.30 mmol / g. Moreover, the specific surface area of the obtained activated carbon A having an oxygen-containing functional group was 1500 m ² / g, the average pore diameter was 0.7 nm, and the total pore volume was 0.78 cm ³ / g.
Next, the trimethylsilanol removal test apparatus 1 shown in FIG. 1 is filled with activated carbon A having an oxygen-containing functional group and 150 ppb of trimethylsilanol containing 150 ppb of trimethylsilanol containing air at a temperature of 23 ° C. and a relative humidity of 45%. Trimethylsilanol removal test was performed using air. The results are shown in Table 1 and FIG.

(Comparative Example 1)
When the oxygen-containing functional group amount of the activated carbon a having a crushed shape average particle size of 32/60 mesh (0.25 to 0.50 mm) and a specific surface area of 1500 m ² / g was measured, the oxygen-containing functional group amount was 0. .39 mmol / g, the amount of carbonyl groups was 0.14 mmol / g, the amount of hydroxyl groups was 0.20 mmol / g, the amount of lactone groups was 0.02 mmol / g, and the amount of carboxyl groups was 0.03 mmol / g.
Next, activated carbon a is filled in the trimethylsilanol removal test apparatus 1 shown in FIG. 1, and trimethylsilanol-containing air having a temperature of 23 ° C. and a relative humidity of 45% is used as 150 ppb of trimethylsilanol-containing air. A silanol removal test was conducted. The results are shown in Table 2 and FIG.

(Analysis of adsorption amount of dimer of silanol compound)
In Example 1 and Comparative Example 1, activated carbon after the trimethylsilanol removal test (in Example 1, after 234.1 hours test, in Comparative Example 1 after 99.3 hours test), respectively, 0.1 g was collected in a vial. Next, 2 mL of dichloromethane was added to the vial and shaken for extraction. Subsequently, the extract was quantitatively analyzed by GC-MS, and the ratio of the trimer of trimethylsilanol and trimethylsilanol in the substance adsorbed on the activated carbon was determined. As a result, in Example 1, trimethylsilanol was 12 mass%, and the dimer of trimethylsilanol was 88 mass%. In Comparative Example 1, trimethylsilanol was 76% by mass, and trimethylsilanol dimer was 24% by mass.

(Example 2)
In the same manner as in Example 1, activated carbon A having an oxygen-containing functional group was obtained.
Next, the trimethylsilanol removal test apparatus 1 shown in FIG. 1 is filled with activated carbon A having an oxygen-containing functional group and 150 ppb of trimethylsilanol containing 150 ppb of trimethylsilanol containing air at a temperature of 23 ° C. and a relative humidity of 35%. Trimethylsilanol removal test was performed using air. The results are shown in Table 3 and FIG.

(Comparative Example 2)
Activated carbon a used in Comparative Example 1 was prepared.
Next, activated carbon a is filled in the trimethylsilanol removal test apparatus 1 shown in FIG. 1, and trimethylsilanol-containing air having a temperature of 23 ° C. and a relative humidity of 35% is used as 150 ppb of trimethylsilanol-containing air. A silanol removal test was conducted. The results are shown in Table 4 and FIG.

(Example 3)
In the same manner as in Example 1, activated carbon A having an oxygen-containing functional group was obtained.
Next, the trimethylsilanol removal test apparatus 1 shown in FIG. 1 is filled with activated carbon A having an oxygen-containing functional group, and 150 ppb of trimethylsilanol containing 150 ppb of trimethylsilanol containing air at a temperature of 23 ° C. and a relative humidity of 25%. Trimethylsilanol removal test was performed using air. The results are shown in Table 5 and FIG.

(Comparative Example 3)
Activated carbon a used in Comparative Example 1 was prepared.
Next, activated carbon a is filled in the trimethylsilanol removal test apparatus 1 shown in FIG. 1 and trimethylsilanol-containing air having a temperature of 23 ° C. and a relative humidity of 25% is used as 150 ppb of trimethylsilanol-containing air. A silanol removal test was conducted. The results are shown in Table 6 and FIG.

  From the time-dependent change of the trimethylsilanol removal rate determined in the trimethylsilanol removal test, the time at which the trimethylsilanol removal rate reached 90% was determined as the 90% removal life (hours). The results are shown in Table 7.

1) Relative humidity: Relative humidity of air containing trimethylsilanol used in the test

Claims (9)

  A silanol compound removing agent, which is activated carbon having an oxygen-containing functional group, wherein the amount of the oxygen-containing functional group per 1 g of the activated carbon having the oxygen-containing functional group is 0.5 mmol / g or more.   The activated carbon having the oxygen-containing functional group has at least one or more of a carbonyl group, a hydroxyl group, a lactone group, and a carboxyl group as the oxygen-containing functional group. Silanol compound remover.   The silanol compound removing agent according to claim 1, wherein the silanol compound is trimethylsilanol.   The activated carbon having an oxygen-containing functional group of 0.5 mmol / g or more per 1 g is brought into contact with the treated air containing the silanol compound to dimerize the silanol compound, and the produced dimer of the silanol compound is A method for removing a silanol compound, wherein the silanol compound in the air to be treated is removed by adsorbing the activated carbon having an oxygen-containing functional group.   The activated carbon having the oxygen-containing functional group has at least one or more of a carbonyl group, a hydroxyl group, a lactone group, and a carboxyl group as the oxygen-containing functional group. A method for removing a silanol compound.   The method for removing a silanol compound according to claim 4 or 5, wherein the silanol compound is trimethylsilanol.   The method for removing a silanol compound according to any one of claims 4 to 6, wherein a relative humidity of the air to be treated containing the silanol compound is 45% or less.   8. The chemical filter for carrying out the silanol compound removal method according to claim 4, wherein activated carbon having an oxygen-containing functional group of 0.5 mmol / g or more per gram is used. .   An exposure apparatus comprising the chemical filter according to claim 8.