JPH08306599A - Air purifying apparatus and aligner - Google Patents

Abstract

PURPOSE: To make it possible to judge a life of a chemical filter easily and accurately, by forming a filter with a part, in which a removing capacity of contamination is smaller than the other part, and providing a contamination detecting sensor downward in a flow at the part. CONSTITUTION: A part 21 in chemical filters 13 and 14 has a thickness D1 smaller than the thickness D2 in the other parts. An ammonia sensor 22 is provided downward in an air flowing direction indicated by an arrow. As an example, when the thickness D1 of the part 21 is 90% of the thickness D2 of the other parts 13 and 14, the removing capacity of contamination in the part 21 becomes almost 90% of the other parts 13 and 14, and the average life span of the part 21 is also 90% of the other parts 13 and 14. In this way, ammonium passed through the filter is detected by the sensor 22 provided downward in the air flow at the part 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an air purifying apparatus and an exposure apparatus, and more particularly to an air purifying apparatus for removing chemical pollutants contained in an air flow by an exchange type high performance filter, and a cleaning by the air purifying apparatus. The present invention relates to an exposure apparatus used in a chamber to be processed.

[0002]

2. Description of the Related Art In recent years, semiconductor integrated circuits have been required to have a higher degree of integration and a minimum line width of the circuit to be formed in a submicron unit. As one of the miniaturization techniques corresponding to the submicron era, it has been proposed to shorten the wavelength of the light source of the projection exposure apparatus for producing a semiconductor integrated circuit. As a short wavelength light source for the projection exposure apparatus, a KrF excimer laser with a wavelength of 248 nm and a wavelength of 193n are currently used.
Attention has been focused on the ArF excimer laser of m, the harmonic of Ti-sapphire, the fourth harmonic of the YAG laser having a wavelength of 266 nm, or the fifth harmonic of the YAG laser having a wavelength of 213 nm.

By the way, conventionally, in an exposure apparatus using a light source having a relatively long wavelength such as g-line and i-line, a resist (photosensitive resin) called a novolac resin and a photosensitive agent has been used. . However, as described above, when the light source wavelength is shortened as in the case of an excimer laser, for example, the light absorption of the resin is increased, so that a conventional novolac-based resist cannot form a pattern with a good shape (cross-sectional shape, etc.) There was found. Therefore, a chemically amplified resist has been developed for an exposure apparatus that uses a short wavelength excimer laser or the like as a light source. This chemically amplified resist is
It is widely used because of its excellent characteristics such as pattern shape, resolution and sensitivity. The chemically amplified resist is generally composed of a resin, a photosensitive acid generator, a dissolution accelerator or a crosslinking agent. Then, an acid is generated from the acid generator upon exposure, and the acid serves as a catalyst at the time of baking (PEB) after exposure to promote the reaction of the dissolution accelerator or the crosslinking agent, thereby forming a pattern by development. It should be noted that the one using the dissolution accelerator forms a positive type pattern, and the one using the crosslinking agent forms a negative type pattern.

Although such a chemically amplified resist is excellent in terms of resolution and sensitivity, it has a problem that it is difficult to control the acid generation by exposure and the catalytic action of acid by PEB, and lacks stability. Particularly in the case of a positive type resist, when a basic gas such as an amine exists in the atmosphere between the exposure and PEB, the acid generated near the resist surface by the exposure reacts with the basic gas and is neutralized. However, a so-called surface insolubilization phenomenon occurs in which the exposed portion that should originally be dissolved in the developing solution becomes insoluble. When the insoluble layer is formed in this way, the formed pattern becomes a T-shape having an eaves on the upper part, which causes a big obstacle such as a reduction in resolution and an influence on a subsequent process such as etching.

Therefore, as disclosed in, for example, Japanese Unexamined Patent Publication No. 6-77114, an attempt has been made to install a chemical filter for removing impurities that cause a chemical reaction on the resist surface in the air conditioning system of the exposure apparatus. FIG. 10 shows an air conditioning system 1 including such a chemical filter 106b.
A schematic structure of a laser exposure apparatus having a No. 03 is shown. Light emitted from a light source (not shown) housed in the light source box 101 illuminates a mask R such as a reticle on which a predetermined circuit pattern is formed through an illumination system, and the circuit pattern is formed on a photosensitive substrate (wafer). Transfer to. These masks and wafers are placed on two stages provided in the main body chamber 102, respectively. The air in the main body chamber 102 is kept clean by the air conditioning system 103. The air conditioning system 103 typically includes a temperature controller 104,
It is composed of an air fan 105 and a filter unit 106. The filter unit 106 is composed of a high performance filter (HEPA filter) 106a and a chemical filter 106b. The air conditioning system 103 circulates the air whose temperature is controlled by the temperature controller 104 by the air fan 105 at a constant wind speed. At that time, the air sent into the main body chamber 102 is the high-performance filter 106.
Contamination such as particles is removed by a, and chemical impurities such as ammonia are removed by the chemical filter 106b, so that a certain degree of cleanliness is maintained. It is also possible to use a replaceable filter as the filter 106 used in the air conditioning system 103. In that case, the filter is replaced at regular intervals or when the predetermined cleanliness cannot be maintained. .

FIG. 11 is a sectional view of a conventional chemical filter 106b used in the air conditioning system 103 shown in FIG. The member 106b indicates a chemical filter using activated carbon or the like as an adsorbent, and the arrow 107 indicates the flow of air.
That is, the air containing chemical impurities enters the chemical filter 106B from the right side of the figure, and physically adsorbs by activated carbon or the like inside the filter, or chemically adsorbed when the activated carbon chemically treated to improve efficiency is used ( The neutralization reaction mechanism is also used to filter out impurities and chemically inactivate them.

[0007]

By the way, the chemical filter 106b of an air conditioning system for an ultraviolet exposure apparatus using a chemically amplified positive resist is required to have a performance of maintaining the ammonia concentration at 1 ppb or less, for example. On the other hand, in general, the average ammonia concentration in a clean room in which a semiconductor manufacturing apparatus is placed is several ppb to several tens p.
Since it is pb, and the chemical filter currently developed and marketed is saturated in several months to several years, it needs to be replaced regularly.

In order to know the replacement timing of the filter,
It is possible to install an ammonia detector on the downstream side of the air flow of the chemical filter and to recognize the time when the ammonia concentration exceeds a predetermined value as the replacement time. However, even the most sensitive sensor for ammonia that is currently being developed has a sensitivity of only about 10 ppb, and when this sensor detects the saturation or breakthrough of the chemical filter, almost the entire surface of the filter is detected. Has reached the end of its service life, and there is a risk that the optimal replacement time may be missed, which was a practical problem.
On the other hand, there is a problem that the maintenance cost of the apparatus increases when the chemical filter is replaced early and early due to fear of saturation and breakthrough.

As a method for measuring the concentration in a low efficiency region of about 1 ppb, for example, air passing through a chemical filter is bubbled in pure water to concentrate the chemical substance,
Although there is a method of analyzing with an ion chromatograph, the method of knowing the life of a chemical filter in a state of being incorporated in an apparatus lacks mobility and cannot be practically used.

The present invention has been made in view of the above-mentioned conventional problems, and can easily and accurately determine the life of a high-performance chemical filter applied to an air conditioning system of a semiconductor manufacturing apparatus. It is an object of the present invention to provide a new and improved air purifying apparatus and exposure apparatus capable of performing the above.

[0011]

In order to solve the above problems, according to the first aspect of the present invention, exchangeable filter means (13, 14) remove contaminants contained in an air flow. A part (21) of the filter means of the air purification device is provided with a portion having a lower decontamination capacity than the remaining part, and a pollutant detection means (22) is provided on the downstream side of the part.

A second aspect of the present invention is an apparatus including an illumination optical system (2) for irradiating a mask with illumination light from a light source, and at least a photosensitive substrate (R) to which a pattern formed on the mask is transferred. A chamber (5) for accommodating a part and an air purifying device (10) for purifying the air in the chamber
And a replaceable filter means (13, 14) for removing contaminants contained in the air flow, provided in at least one of an air circulation path in the chamber or an outside air intake port into the chamber. A part of the filter means (21) having a contamination removal capacity lower than that of the remaining part is provided, and a contaminant detection means (22) is provided downstream of the part.

Further, a load means (30) is provided at a portion of the filter means having a low decontamination capacity to offset a reduction in pressure loss caused by making the decontamination capacity of that portion lower than the remaining portion. It is also possible to provide. The filter means may be, for example, a chemical filter that removes or deactivates the basic substance in the air to be treated.

[0014]

If the air purifying device constructed as described above is continuously used in, for example, a clean room in which a semiconductor manufacturing apparatus is installed, first, a portion of the filter means having a low decontamination capacity is saturated and breakthrough occurs. Therefore, by detecting the breakthrough of the filter means by the pollutant detection means provided on the downstream side of the part, the life of the entire filter can be accurately and easily made before the filter means is totally saturated and breakthrough occurs. It becomes possible to predict and prepare for filter replacement, and the filter replacement time is not missed.

When the air purifying apparatus as described above is applied to an exposure apparatus, particularly an ultraviolet projection exposure apparatus using a chemically amplified positive resist, for example, basic substances in the air are removed or inactivated. If a basic substance such as ammonia breaks through the filter and flows into the chamber of the body, it reacts with the resist and makes its surface difficult to dissolve. It is possible to avoid it.

In the portion where the decontamination capacity of the filter is reduced, the aerodynamic load resistance (pressure loss) becomes relatively small, and more air flows into that portion. As a result, that part of the filter saturates faster,
It may reach the end of its life. In such a case, it is difficult to accurately predict the service life of the entire filter, but according to the present invention, the pressure loss is compensated by the load means (for example, a chemically inert filter), so that replacement is required. Accurate prediction of the time is possible.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the accompanying drawings. 1 is a schematic side view of an exposure apparatus using a laser light source to which the present invention can be applied, and FIG. 2 is a schematic plan view of the exposure apparatus shown in FIG. In FIG. 2, details of the light source and the illumination optical system are omitted in order to simplify the configuration and facilitate understanding of the invention.

Excimer light (hereinafter referred to as DUV light) emitted from a light source 1 such as a KrF-based or ArF-based excimer laser is shaped into a required beam shape and size by a beam shaping system (not shown). After passing through an illumination system section 2 including various integrators such as relay lenses, various mirrors and fly-eye lenses, and illuminance equalizing means such as condenser lenses, the light enters a mask R having a predetermined pattern, and the mask pattern is formed. Is imaged on the wafer W mounted on the XY stage 3 via the projection optical system (refractive system, reflective system, catadioptric system) PL. In this embodiment, it is assumed that the wafer W is coated with a chemically amplified photosensitizer. In the illustrated example, the light source 1 part is housed in the light source chamber 4, and the apparatus main body part including the mask R, the projection optical system PL, and the stage 3 is housed in the main body chamber 5.

An air conditioning system 10 regulates the temperature and humidity and cleans the interior of the main body chamber 5. The air conditioning system 10
The temperature controller 11 and the blower fan 12 arranged in the air path around the main body chamber 5, and the first air conditioner arranged over the entire intake port of the main body chamber 5 to clean the air supplied into the main body chamber 5. It is mainly composed of one filter unit 13. In the illustrated example, the outside air intake OA
And a second filter unit 14 for cleaning the outside air taken in. Further, the first and second filter units 13 and 14 respectively remove high-performance filters such as HEPA filters and ULPA filters for removing physical contaminants such as particles, and chemical contaminants such as ammonia components. And a chemical filter for.

During air conditioning, the outside air taken in from the outside air inlet OA is combined with the air flow circulating in the main chamber 5 by the blower fan 12 after the particles and chemical components are removed by the second filter unit 13. Then, the temperature is adjusted to the optimum temperature by the temperature controller 11. Although not shown, a humidity adjuster may be installed upstream or downstream of the temperature adjuster 11 to adjust the temperature of the circulating air flow and the humidity. Further, in the illustrated example, the outside air is naturally taken in from the outside air intake OA according to the pressure difference between the inside and outside of the chamber, but another fan is provided at the outside air intake OA to forcibly enter the room. It can also be configured to take in outside air.

The air whose temperature is controlled by the temperature controller 11 as described above is blown by the blower fan 12 into the first filter unit 13
And the particles and chemical components are removed by the first filter unit 13, and then the particles are supplied into the main body chamber 5 in which an apparatus such as a projection exposure apparatus and a stage is housed. At this time, the first filter unit 13 is arranged on the entire one side surface (upstream side) of the main body chamber 5, and the exhaust surface made of, for example, punching metal is formed on the entire other side surface (downstream side) of the main body chamber 13. Is formed, clean air can be supplied as a laminar flow into the main body chamber 5. Of course, the present invention is not limited to the configuration of this embodiment, and if necessary, the first filter unit 13 may be provided on the upper surface of the main body chamber 5 so as to blow out the upper surface, or the first filter unit and the main body may be blown. It is also possible to configure the air outlet to the chamber as a separate body and connect the both by an air path such as a duct.

In the illustrated example, the filter unit is installed only at the air inlet of the main body chamber and the outside air inlet of the air conditioning system, but in addition to this, for example, the blower fan 12
It is also possible to provide a filter unit at the outlet of the air conditioner, the outlet of the temperature controller 11, and the like to prevent contaminants generated by the blower fan 12 and the temperature controller 11 from being mixed into the circulating air. Is. In short, any configuration and arrangement can be adopted as long as the pollutants (particles and chemical substances) can be filtered from the air supplied to the main chamber by disposing the filter unit in the outside air intake port or the air circulation path. It is also possible.

Each filter unit chemically removes high-performance filters such as HEPA filters and ULPA filters that physically collect particles existing in the circulating air and chemical substances such as ammonia existing in the circulating air. Or a chemical filter for neutralization. Of course, the filter unit may be configured with only one of the high-performance filter and the chemical filter depending on the installation location. As the high-performance filter, it is possible to use an IES-compliant commercially available filter that uses glass fiber or glass asbestos fiber as a filtering agent. As the chemical filter, an activated carbon filter, a zeolite filter, an ion exchange resin filter or the like can be used.

The activated carbon filter is basically effective against most chemical pollutants (ions, gases, organic substances), but generally, the organic compound has a large molecular size and a large intermolecular force. Those with low solubility in water,
The lower the polarity, the higher the adsorptivity. When selecting an activated carbon filter, it is necessary to consider the surface area and average pore diameter of activated carbon, as well as the shape and dust generation of activated carbon, and the surface area is large and the pore diameter matches the molecular weight of the collection target. Is good. Examples of these include a filter obtained by subjecting a phenol resin to an active carbonization treatment, for example, Kuraray Chemical Co., Ltd., or a filter in which powdered activated carbon is added to polyester fiber, for example, Extraction System Ink Vapor Soap 1076. Etc. can be used. Further, it is also possible to use activated carbon which is impregnated with an acidic substance or a weak alkaline substance to enhance the adsorption efficiency of acid or alkali. These include Kuraray Chemical's Kurasheet TB or T-F obtained by impregnating polyether urethane foam or polyester urethane foam with coconut shell powder activated carbon (for example, when removing basic gas, When using a TB type filter impregnated with an acidic substance and removing acetaldehyde, formaldehyde, etc., a TF type filter impregnated with a weak alkaline substance can be used), or an extraction system ink. There is Vapor Soap 1073K manufactured by the company (which can be used, for example, when removing acid and NH ₃ ). Zeolite, like activated carbon, is effective against most chemical pollutants (ions, gases, organic substances), and it is necessary to select the pore size according to the size of the pollutant to be removed.

Further, ionic chemical impurities (NH ₄ ⁺ ,
For removal of amine, SO ₄ ²⁻ , NO _x ) etc., for example, ion exchange fibers produced from polypropylene fibers by radiation graft polymerization or ion exchange fiber filters using ion exchange resins can be used. There are two types of ion exchange fibers, acidic cation exchange fibers and basic anion exchange fibers, and they can be used properly according to the polarity of the intended ion. Then, + ions such as NH ₄ ⁺ and amine and basic gas can be adsorbed by the acidic cation exchange fiber, and − ions such as SO ₄ ²⁻ and NO _x and acidic gas can be adsorbed by the basic anion exchange fiber. For example, NH ₄ ⁺ can adsorb about 90% or more even at a low concentration by an ion exchange reaction with a strongly acidic cation exchange fiber. Further, the − ion is adsorbed by the ion exchange reaction with the basic anion exchange fiber.

By configuring the air conditioning system 10 as described above, contaminants such as particles and chemical substances are removed from the air flowing into the main body chamber 5, and the exposure operation is performed in a cleaner environment. Is possible. However, for chemically amplified positive resists that require ammonia to be maintained at 1 ppb or less by removing ammonia from a normal clean room air having an average ammonia concentration of several ppb to several tens of ppb by a chemical filter. When a processing environment of 1) is constructed, the chemical filter currently developed and marketed will be saturated in several months to several years. Therefore, in order to maintain the yield above a certain level, it is necessary to regularly replace the chemical filter.

In this respect, in the conventional system, in order to know the replacement timing of the filter, an ammonia detector is installed downstream of the air flow of the chemical filter, and the time when the ammonia concentration exceeds a predetermined value is the replacement time. Was certified. However, even the most sensitive sensor for ammonia that is currently being developed has a sensitivity of only about 10 ppb, and when this sensor detects saturation or breakthrough of the chemical filter, almost the entire surface of the filter As mentioned above, the product has reached the end of its service life, and there is a risk that it will miss the optimal replacement time, causing practical problems.

In order to avoid such a situation, in this embodiment, the filter replacement timing detection parts 21a and 21b and the ammonia sensors 22a and 22b are provided in a part of the filters 13 and 14.
Is provided. An enlarged view of this portion is shown in FIG. As shown in the figure, according to the first embodiment of the present invention, the thickness (D1) of the part 21 of the chemical filters 13, 14 is made thinner than the thickness (D2) of the other part. Then, the ammonia sensor 22 is provided on the downstream side with respect to the direction of the air flow indicated by the arrow.
Is provided. Now, in the chemical filters 13 and 14 configured in this way, for example, the thickness (D
If 1) is set to about 90% of the thickness (D2) of the other portions 13 and 14, the decontamination capacity of that portion 21 becomes about 90% of the decontamination capacity of the other portions 13 and 14, and on average The life is reached in about 90% of the time of the other parts 13 and 14. That is, in an environment in which the life of the entire filter is about 10 months, the portion 21 reaches the end of its life before the other portions in about 9 months from the start of use, and the filter breaks through this portion 21. Ammonia sensor 22 installed on the downstream side detects ammonia that has passed through the filter. As a result, it is possible to schedule a chemical filter replacement with a margin approximately one month before the life of the entire filter is reached, so that the replacement time may be missed or a filter that can withstand sufficient use may be replaced. You can avoid such a situation.

FIG. 4 is an indirect graph indirectly showing the time-dependent change in the decontamination ratio of the chemical filter. The horizontal axis represents time and the vertical time represents the concentration of the impure chemical substance after passing through the filter. Curve 2 shows the characteristics of the concentration directly below the member 21.
At 3 ′, the change in concentration of the entire filtration system is shown by the curve 23. Concentration level Th of chemical substances allowed in this filtration system
(Threshold value), the life of the thin filter member 21 is L1, and the life of the whole (filter members 13, 14) is L3.
It is represented by. As shown in the figure, once the chemical filter is saturated, the contamination removal rate deteriorates sharply. Therefore, if the filter was replaced when L3 was reached, it would be too late and an exposure apparatus including a chemically amplified resist would be used. May cause damage. In this respect, according to the present invention, it is possible to predict the time point of L3 when the life of the entire filter is reached at the time point of L1 with a margin, so that the replacement time is not missed.

The cross-sectional area of the entire chemical filter 13 of the air conditioning system 10 of the main body chamber 5 accommodating the exposure apparatus shown in FIGS. 1 and 2 is 3 to 4 square meters, and the contamination removal for detecting the replacement time of the filter is performed. Since the cross-sectional area of the low-capacity portion 21 is several square centimeters at most, the breakthrough of the portion has a negligible effect on the entire device. Furthermore, by setting the place where the portion 21 having a low decontamination capacity is installed as far as possible from the wafer (and hence resist) processing area of the exposure apparatus, the influence on the apparatus is further reduced, and the filter can be replaced more safely. The time can be detected.

5 to 6 show some examples of providing the chemical filter with a portion having a low contamination removal capacity for detecting the filter replacement time. In general, the chemical filters 13 and 14 are hermetically housed in the casing 24, and therefore, as shown in FIG.
5 as a separate body, in which Δd is provided more than the filters 13 and 14 of the main body part in order to reduce the decontamination capacity.
Filter for detecting when to replace the filter 2 that is thin
1 can be configured to be housed. Alternatively,
As shown in FIG. 6, a through hole 26 is provided in the filters 13 and 14 of the main body portion, and a filter replacement timing detection filter 21 that is thinner than the filters 13 and 14 of the main body portion by Δd is provided in the through hole 26. Cylindrical casing 2 to accommodate
5'can be configured to fit. Alternatively, as shown in FIG. 7, the filters 13, 14 of the main body
A filter replacement timing detection filter 21, which is configured to be thinner than the filters 13 and 14 of the main body by Δd without using the casings 25 and 25 ′, is airtightly provided on a part of Can be configured to fit in.

In the above embodiment, the filter replacement time detection filter 21 is replaced by the filters 13 and 14 of the main body.
However, the present invention is not limited to such an embodiment. For example, when the filters 13 and 14 of the main body portion are formed by laminating thin filters, it is possible to reduce the decontamination capacity of that portion by reducing the number of laminated filter replacement time detection portions 21. is there. Further, in each of the above-described embodiments, the filter of the filter replacement timing detection portion is configured to be thinner than the other portions, thereby reducing the contamination removal capacity of that portion.However, the present invention is not limited to this embodiment. Not limited. For example, when an activated carbon filter is used, it is possible to use an activated carbon filter with a small decontamination capacity for the filter replacement time detection part even if it has the same thickness as the filter of the main body part, depending on the cross-sectional area and average fine efficiency. is there. Alternatively, when using an activated carbon filter impregnated with an adsorbent, even if it has the same thickness as the filter of the main body,
An activated carbon filter having a small decontamination capacity depending on the amount of the adsorbed substance can be used for the filter replacement timing detection part.

FIG. 8 shows a filter replacement time detection portion 21.
Another example of a pollutant detection means installed downstream of is shown. In this embodiment, instead of installing the chemical sensor 22 directly under the filter portion 21, a sampling tube 28 is installed, and after sampling the air flow downstream of the filter portion 21, a sensor module 29 installed at a remote place. To detect pollutants. With such a configuration, it is not necessary to configure the sensor 22 itself in a small size as in the previous embodiment, so that the degree of freedom in sensor selection can be increased. When the configuration shown in FIG. 8 is adopted, a small suction pump is built in, and the air that has passed through the chemical filter portion 21 is collected in the sampling tube 2
It is preferable that it is configured so that it can be efficiently collected.

FIG. 9 shows still another embodiment of the filter replacement timing detecting portion 21 constructed according to the present invention. In this embodiment, in addition to the configuration shown in FIG.
An aerodynamic load resistance member 30 is added in series to the thin filter portion 21 '. As in the embodiment shown in FIG. 3, when the decontamination capacity is reduced by making the thickness of the filter replacement time detection portion 21 thin, the aerodynamic load resistance (pressure loss) of that portion 21 is different. Part 1
Since it is smaller than those of Nos. 3 and 14, the airflow indicated by the arrow flows into the portion 21 more. Therefore, the member 21 will be saturated more rapidly and will reach the end of its life, and there is a possibility that the saturation time (life) of the entire filters 13, 14 cannot be accurately predicted due to the saturation of the member 21. In order to avoid such inconvenience, in the embodiment shown in FIG.
A particle filter 30 (HEPA filter or the like) which is chemically inactive is attached to the above-mentioned portion 21 by the chemical filter 2.
It is arranged in series with 1 to offset the reduced pressure loss. As a result, the flow rate of the air passing through the filter replacement timing detection portion 21 is adjusted to the other filter body portion
Since it is possible to make the flow rate of the air passing through 3 and 14 substantially equal, it is possible to more accurately predict the replacement time of the filter.

Now, as described above, the pollutant detection means 2 provided downstream of the filter replacement timing detection portion 21.
The detection signal of 2 is sent to the controller 31. And
When the pollutant detection means 22 detects a pollutant composed of a basic substance such as ammonia, or when the detected value reaches a predetermined threshold value, the filter portion 21 causes the filter main body portions 13 and 14 to pass. Since it is possible to determine that saturation has occurred and a breakthrough has occurred (that is, the life has been reached) prior to, the controller 31 displays the information on the display 32 and notifies the operator of the time to replace the filter. To do. As a result, the operator can replace the filter without delaying the replacement time and with a sufficient time margin. Of course, the exposure operation may be automatically stopped at the time when the pollutant detection means 22 detects a pollutant of an allowable amount or more, or after a lapse of a certain period from that time.

In the above embodiments, the case where the present invention is applied to the main chamber in which the exposure apparatus using the chemically amplified positive resist is housed has been described as an example, but the present invention is applicable. It is not limited to the embodiment. In addition to this, it can be suitably applied to an air conditioning system of a chamber that accommodates an optical system in which fogging is caused by irradiation with light in the ultraviolet region (UV light or DUV light). Further, the present invention is not limited to the exposure apparatus, but can be applied to all kinds of semiconductor manufacturing apparatuses such as an etching apparatus and an ashing apparatus that require processing in a clean environment in which physical contaminants and chemical contaminants are removed. It can also be applied. Further, it can be particularly suitably applied to a device which is sensitive to the contamination of an extremely small amount of chemical contaminants. Furthermore, the present invention is not limited to semiconductor manufacturing equipment, and can be used to determine the replacement time of any air conditioning system filter that requires a clean environment in which contaminants are removed by the filter unit means. .

[0037]

As described above, according to the present invention,
Since the filter part having the decontamination capacity set lower than that of the other filter parts is provided, the filter part is saturated earlier than the other parts and the contaminants pass through. Therefore, by installing pollutant detection means downstream of the filter part,
By detecting contaminants, the life of the entire filter can be accurately predicted before the entire filter is saturated and has reached the end of its life, so that the filter replacement time is not missed. In particular, when applied to an exposure apparatus that uses a chemically amplified resist, it is possible to know the leakage of the basic gas due to the saturation of the filter, so that the surface insolubilization phenomenon of the resist can be prevented and higher resolution can be achieved. Exposure becomes feasible.

[Brief description of drawings]

FIG. 1 is a schematic view showing the arrangement of an exposure apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic view of the exposure apparatus shown in FIG. 1 viewed from above.

FIG. 3 is a schematic enlarged view of a filter replacement timing detection portion according to an embodiment of the present invention.

FIG. 4 is a graph showing changes over time in the contamination removal rate of a filter.

FIG. 5 is an explanatory diagram showing an outline of an embodiment of a filter replacement timing detection portion according to the present invention.

FIG. 6 is an explanatory view showing the outline of another embodiment of the filter replacement timing detection portion according to the present invention.

FIG. 7 is an explanatory view showing the outline of still another embodiment of the filter replacement timing detection portion according to the present invention.

FIG. 8 is an explanatory view showing the outline of another embodiment of the contaminant detection means according to the present invention.

FIG. 9 is an explanatory view showing the outline of still another embodiment of the filter replacement timing detection portion according to the present invention.

FIG. 10 is a schematic view of a conventional exposure apparatus having an air conditioning system as viewed from above.

11 is a schematic view of a filter portion applicable to the exposure apparatus shown in FIG.

[Explanation of symbols]

 1 Light Source 2 Illumination System 3 Stage 5 Main Chamber 10 Air Conditioning System 11 Temperature Controller 12 Blower Fan 13 Filter Unit 14 Filter Unit 21 Filter Replacement Timing Detection Part 22 Contaminant Detection Means 31 Controller 32 Display R Reticle W Wafer PL Projection Optical System

Claims (4)

[Claims] 1. An air purifying device for removing pollutants contained in an air flow by exchangeable filter means, wherein a part of the filter means is provided with a part having a decontamination capacity lower than that of the remaining part. An air purification apparatus, characterized in that a pollutant detection means is provided on the downstream side of the site. 2. An illumination optical system for irradiating a mask with illumination light from a light source, a chamber for accommodating at least an apparatus portion including a photosensitive substrate on which a pattern formed on the mask is transferred, and air in the chamber. In an exposure apparatus having an air purifying device for cleaning, at least one of an air circulation path in the chamber or an outside air intake port into the chamber is provided with exchangeable filter means for removing contaminants contained in an air flow. An exposure apparatus, characterized in that a part of the filter means having a contamination removal capacity lower than that of the remaining part is provided, and a contaminant detection means is provided downstream of the part. 3. A load means is provided at the portion of the filter means for offsetting a reduction in pressure loss caused by making the contamination removal capacity of the portion lower than that of the remaining portion. The exposure apparatus according to claim 2. 4. The exposure apparatus according to claim 2, wherein the filter means is a chemical filter that removes or inactivates a basic substance such as amine in the air.