JP2003257823A - Optical device and aligner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical device which is capable of eliminating water contained in a space on an optical path and surely reducing light absorbing materials including water in the space. <P>SOLUTION: The optical device PL is equipped with empty spaces 250 to 254 which are formed on the optical path of an energy beam IL and supplied with a prescribed gas. Furthermore, the optical device PL is equipped with a temperature control device 204 that controls temperature of the prescribed gas so as to increase the amount of saturated moisture inside the empty spaces 250 to 254. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an optical device formed on the optical path of an energy beam and having a space to which a predetermined gas is supplied, and more particularly to a semiconductor device, a liquid crystal display device, an image pickup device (CCD, etc.). , An optical device used in an exposure apparatus for manufacturing an electronic device such as a thin film magnetic head.

[0002]

2. Description of the Related Art When manufacturing a device (electronic device) such as a semiconductor element (integrated circuit) or a liquid crystal display panel in a photolithography process, a mask or a reticle (hereinafter referred to as "mask" or "reticle") is exposed by an illumination light for exposure (exposure beam) , Reticle), and transfers a reticle pattern (circuit pattern) onto a substrate (a wafer coated with a photosensitive agent, a glass plate, etc.) via a projection optical system. The circuit of the electronic device is transferred by exposing the circuit pattern on the substrate with the projection exposure apparatus, and is formed by post-processing. An integrated circuit is formed by repeatedly layering the circuit wiring thus formed, for example, for about 20 layers.

In recent years, high-density integration of integrated circuits, that is, miniaturization of circuit patterns has been promoted.
The exposure beam in the exposure apparatus tends to have a shorter wavelength. That is, as the exposure beam, the KrF excimer laser (wavelength: 248 nm) will be used instead of the emission line of the mercury lamp that has been the mainstream until now, and the practical application of the shorter wavelength ArF excimer laser (193 nm) will be the final stage. I am entering. In addition, research on F ₂ lasers (157 nm) and Ar ₂ lasers (126 nm) is underway with the aim of achieving higher density integration.

Light (energy beam) having a wavelength of about 120 nm to 200 nm belongs to the vacuum ultraviolet region, and these lights (hereinafter referred to as vacuum ultraviolet light) do not pass through air. This is because light energy is absorbed by molecules of oxygen, water, carbon dioxide gas, organic substances, halides and the like (hereinafter, referred to as “light absorbing substance”) contained in the air.

[0005]

Therefore, in an optical device that constitutes an exposure apparatus using vacuum ultraviolet light, in order to make the exposure beam reach the substrate with sufficient illuminance and sufficient illuminance uniformity, the exposure beam It is necessary to eliminate as much as possible a gas containing a light-absorbing substance such as oxygen from the space on the optical path. As a method of eliminating the light absorbing substance, there is known a method of filling the space on the optical path with a gas having a low energy absorption of vacuum ultraviolet light (low absorptive gas).

However, even if the space on the optical path is filled with the low absorption gas, water adhering to the surface of the member in the space is likely to remain, and the water is removed from the space.
It takes a lot of time.

The present invention has been made in view of the above-mentioned circumstances, and it is possible to eliminate water contained in a space on an optical path in a short time and surely reduce a light-absorbing substance in the space including water. It is an object of the present invention to provide an optical device capable of
Another object of the present invention is to provide an exposure apparatus capable of improving throughput and exposure accuracy.

[0008]

The optical device (P
In the optical device (PL), L is a space (250 to 254) formed in the optical path of the energy beam (IL) and having a space (250 to 254) to which a predetermined gas is supplied.
254) is provided with a temperature control device (204) for controlling the temperature of the predetermined gas so as to increase the saturated water content. In this optical device, since the temperature of the predetermined gas supplied to the space is controlled by the temperature control device so that the amount of saturated water in the space on the optical path increases, the water in the space easily evaporates. . Therefore, by discharging the gas containing the evaporated water, the water in the space can be removed in a short time.

In this case, the temperature control device (2
In 04), it is preferable to control the temperature of the predetermined gas to a temperature higher than room temperature. Thereby, evaporation of water in the space (250 to 254) on the optical path can be promoted.

The exposure apparatus (10) of the present invention comprises an illumination optical system (21) for illuminating a mask (R) having a pattern formed thereon with an energy beam (IL), and the mask (R).
Of the projection optical system (P
At least one of L) and the optical device is provided. In this exposure apparatus, water is removed from the space on the optical path in a short time, and the light-absorbing substance in the space including water is surely reduced, so that exposure accuracy and throughput can be improved.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below. FIG. 1 shows an overall configuration of a reduction projection exposure apparatus 10 for manufacturing a semiconductor device according to an embodiment, which includes the optical apparatus according to the present invention as a projection optical system. Further, in FIG. 1, an XYZ rectangular coordinate system is adopted. XYZ
In the orthogonal coordinate system, the X axis and the Y axis are set so as to be parallel to the wafer stage WS that holds the wafer W as a substrate (photosensitive substrate), and the Z axis is a direction orthogonal to the wafer stage WS. Is set to. Actually, X in the figure
In the YZ orthogonal coordinate system, the XY plane is set to a plane parallel to the horizontal plane, and the Z axis is set to the vertical direction.

The exposure apparatus according to this embodiment uses an F ₂ laser light source as an exposure light source. Further, one shot area on the wafer W is obtained by synchronously scanning the reticle R and the wafer W in a predetermined direction relative to an illumination area having a predetermined shape on the reticle R as a mask (projection original plate). In addition, a step-and-scan method for sequentially transferring the pattern image of the reticle R is adopted. In such a step-and-scan type exposure apparatus, the pattern of the reticle R can be exposed in an area on the substrate (wafer W) wider than the exposure field of the projection optical system.

In FIG. 1, an exposure apparatus 10 includes a laser light source 20, an illumination optical system 21 for illuminating a reticle R with an exposure beam IL as an energy beam from the laser light source 20, and an exposure beam IL emitted from the reticle R.
A projection optical system PL for projecting the image onto the wafer W, a main controller (not shown) for controlling the entire apparatus, and the like are provided. Further, the exposure apparatus 10 is housed inside a large chamber (not shown) as a whole.

The laser light source 20 has, for example, an oscillation wavelength 157.
It has an F ₂ laser which outputs a pulsed ultraviolet light of nm. Further, the laser light source 20 is provided with a light source control device (not shown), and the light source control device has an oscillation center wavelength and a spectrum half width of the pulsed ultraviolet light emitted in response to an instruction from the main control device. Control, pulse oscillation trigger control, gas control in the laser chamber, etc. are performed.

The pulsed laser light (illumination light) from the laser light source 20 is deflected by the deflection mirror 30 and is incident on the variable light attenuator 31 as an optical attenuator. Variable dimmer 3
In No. 1, the extinction ratio can be adjusted stepwise or continuously in order to control the exposure amount for the photoresist on the wafer. The illumination light emitted from the variable light attenuator 31 is deflected by the optical path deflecting mirror 32, and then passes through the first fly-eye lens 33, the zoom lens 34, the vibrating mirror 35, and so on to the second fly-eye lens 36 in order. Reach On the exit side of the second fly-eye lens 36, a switching revolver 37 for the aperture stop of the illumination optical system for setting the size and shape of the effective light source as desired is arranged. In the present embodiment, in order to reduce the light amount loss at the aperture stop of the illumination optical system, the size of the light flux to the second fly-eye lens 36 by the zoom lens 34 is variable.

A light beam emitted from the aperture of the illumination optical system aperture stop illuminates an illumination field stop (reticle blind) 41 through a condenser lens group 40. The illumination field stop 41 is disclosed in JP-A-4-196513 and the corresponding US Pat. No. 5,473,410.

The light from the illumination field stop 41 is guided onto the reticle R via an illumination field stop image forming optical system (reticle blind image forming system) including deflection mirrors 42 and 45 and lens groups 43, 44 and 46. On the reticle R, an illumination area which is an image of the opening of the illumination field stop 41 is formed. Light from the illumination area on the reticle R is guided onto the wafer W via the projection optical system PL, and on the wafer W, the reticle R is lit.
A reduced image of the pattern in the illuminated area of is formed. The reticle stage RS holding the reticle R is two-dimensionally movable in the XY plane, and its position coordinates are measured and controlled by the interferometer 50. The wafer stage WS that holds the wafer W is also two-dimensionally movable in the XY plane, and its position coordinates are measured and controlled by the interferometer 51. With these, reticle R
Also, the wafer W can be synchronously scanned with high accuracy. An illumination optical system 21 is configured by the laser light source 20 to the illumination field stop imaging optical system described above.

When the exposure beam is light in the vacuum ultraviolet region, such as the F ₂ laser light (wavelength: 157 nm) used in this embodiment, an optical glass material (optical element) having good transmittance is used. Limited to fluorite (crystal of CaF ₂ ), quartz glass doped with fluorine or hydrogen, magnesium fluoride (MgF ₂ ), and the like. In this case, the projection optical system PL
In the above, it is difficult to obtain a desired image forming characteristic (chromatic aberration characteristic or the like) by using only the refractive optical member, and therefore, a catadioptric system combining a refractive optical member and a reflecting mirror may be adopted.

When light in the vacuum ultraviolet region is used as the exposure beam, oxygen, water (water vapor), hydrocarbon-based substances (carbon monoxide, carbon dioxide, etc.), organic substances, halides, etc. are emitted from the optical path. It is necessary to exclude a substance having a strong absorption characteristic for light in the wavelength band (hereinafter, referred to as “absorption substance” as appropriate). Therefore, in the present embodiment, the illumination optical path (the laser light source 20 to the optical path to the reticle R) and the projection optical path (the optical path to the reticle R to the wafer W) are blocked from the external atmosphere, and these optical paths are converted into light in the vacuum ultraviolet region. On the other hand, a gas such as nitrogen, helium, argon, neon, krypton, xenon, radon, etc., which is a low-absorbent gas having a property of little absorption, or a mixed gas thereof (hereinafter referred to as "low-absorbent gas" or "purge gas" as appropriate). Call).

Specifically, the optical path from the laser light source 20 to the variable dimmer 31 is blocked from the external atmosphere by the casing 60, and the optical path from the variable dimmer 31 to the illumination field stop 41 is blocked from the external atmosphere by the casing 61. The illumination field stop imaging optical system is shielded from the external atmosphere by the casing 62, and the optical path thereof is filled with the low absorptive gas. The casing 61 and the casing 62 are connected by the casing 63. The lens barrel 69 of the projection optical system PL itself is also a casing, and the internal optical path thereof is filled with the low-absorption gas.

Further, the casing 64 shields the space between the casing 62 accommodating the illumination field diaphragm imaging optical system and the projection optical system PL from the external atmosphere, and the reticle stage holding the reticle R therein. RS is stored. The casing 64 is provided with a door 70 for loading and unloading the reticle R, and the outside of the door 70 prevents the atmosphere in the casing 64 from being polluted when the reticle R is loaded and unloaded. A gas replacement chamber 65 is provided for this purpose. The gas replacement chamber 65 is also provided with a door 71, and the reticle is transferred to and from the reticle stocker 66 that stores a plurality of types of reticles.

The casing 67 is a projection optical system PL.
The space between the wafer W and the wafer W is shielded from the external atmosphere, and the wafer stage WS for holding the wafer W via the wafer holder 80, the position (focus position) in the Z direction of the surface of the wafer W, and the inclination thereof are provided inside the space. Oblique incidence type autofocus sensor 81 for detecting an angle, off-axis type alignment sensor 82, wafer stage WS
A surface plate 83 and the like on which the is mounted are stored. A door 7 for loading / unloading the wafer W is provided in the casing 67.
2 is provided, and a gas replacement chamber 68 for preventing the atmosphere inside the casing 67 from being contaminated is provided outside the door 72. The gas replacement chamber 68 has a door 7
3 is provided, and the loading of the wafer W into the apparatus and the unloading of the wafer W to the outside of the apparatus are performed via the door 73.

Nitrogen or helium is preferably used as the low absorptive gas (purge gas) filled in the space on each optical path. Nitrogen acts as a light-absorbing substance for light with a wavelength of about 150 nm or less, and helium has a wavelength of 100 n.
It can be used as a low-absorbing gas for light of about m or less. Helium has a thermal conductivity about 6 times that of nitrogen, and the amount of fluctuation in the refractive index with respect to changes in atmospheric pressure is about 1/8 that of nitrogen.
Therefore, it is particularly excellent in high transmittance, stability of image forming characteristics of the optical system, and cooling property. Note that helium may be used as the low-absorbing gas for the barrel of the projection optical system PL, and nitrogen may be used as the low-absorbing gas for other optical paths (for example, the illumination optical path from the laser light source 20 to the reticle R).

Here, the casings 61, 62, 64, 6
7, each of the air supply valves 100, 101, 102, 1
03 are provided, and these air supply valves 100 to 103 are provided.
Is connected to an air supply line in a gas supply system described later. Further, the exhaust valves 110, 111, 112, 113 are provided in the casings 61, 62, 64, 67, respectively.
Are provided, and the exhaust valves 110 to 113 are
Each is connected to an exhaust pipe line in the gas supply system.

Similarly, gas replacement chambers 65 and 68 are provided with air supply valves 104 and 105 and exhaust valves 114 and 115, respectively.
The lens barrel 69 of the projection optical system PL is also provided with an air supply valve 106 and an exhaust valve 116, which are connected to an air supply pipe line or an exhaust pipe line in the gas supply system.

In the gas replacement chambers 65 and 68,
It is necessary to perform gas replacement at the time of reticle exchange or wafer exchange. For example, when replacing the reticle, the door 71 is opened and the reticle is moved from the reticle stocker 66 to the gas replacement chamber 6
5, the door 71 is closed and the gas replacement chamber 65 is filled with the low absorptive gas, then the door 70 is opened and the reticle is placed on the reticle stage RS. Further, when the wafer is replaced, the door 73 is opened to carry the wafer into the gas replacement chamber 68, and the door 73 is closed to fill the gas replacement chamber 68 with the low absorption gas. Thereafter, the door 72 is opened and the wafer is placed on the wafer holder 80. The reverse procedure is used for reticle carry-out and wafer carry-out. When replacing the gas in the gas replacement chambers 65 and 68, the atmosphere in the gas replacement chamber may be decompressed, and then the low absorption gas may be supplied from the air supply valve.

Further, in the casings 64 and 67,
There is a possibility that the gas that has undergone the gas replacement by the gas replacement chambers 65 and 68 may be mixed, and a considerable amount of light-absorbing substances such as oxygen may be mixed into the gas of the gas replacement chambers 65 and 68. high. Therefore, it is desirable to perform gas replacement at the same timing as gas replacement in the gas replacement chambers 65 and 68. Further, it is preferable that the casing and the gas replacement chamber are filled with a low-absorbent gas having a pressure higher than the pressure of the external atmosphere.

FIG. 2 shows an example of the configuration of a gas supply system 200 for supplying the above-mentioned low-absorptive gas as a purge gas to each space on the optical path of the above-mentioned exposure beam. The gas supply system 200 includes a gas supply source 201 such as a gas cylinder that stores a predetermined low-absorption gas, a gas supply device 202 that supplies the low-absorption gas to each space on the optical path,
An exhaust device 203 for discharging a gas containing a low-absorbent gas from each space on the optical path, a temperature controller 204 for controlling the temperature of the low-absorbent gas, and a concentration of a light-absorbing substance in each space on the optical path are measured. It has densitometers 205a to 205e and a control device 206 for controlling the above devices in a centralized manner.

In FIG. 2, as the supply destination of the low absorption gas,
Of the spaces on the optical path of the exposure beam described above, a plurality of spaces 250 to 254 inside the lens barrel 69 in the projection optical system PL.
(Hereinafter, referred to as a purge space) is representatively shown.
The plurality of purge spaces 250 to 254 are arranged adjacent to each other with the optical members (lens elements) 300 to 303 interposed therebetween. In this example, helium gas is used as the purge gas to be supplied to the space on the optical path from the viewpoint of the stability of the imaging characteristics. However, since the helium gas is expensive, the wavelength of the exposure beam is F
_{When the} wavelength is 150 nm or more like _two lasers, nitrogen gas may be used as a purge gas in order to reduce the operating cost.

The gas supply device 202 is a gas supply source 201.
By pressurizing the helium gas sent from, for example, the helium gas is supplied to each of the purge spaces 250 to 254 via the air supply line 210. In this example, the air supply valve 106 whose flow rate can be adjusted for each of the purge spaces 250 to 254.
a to 106e are provided, and the air supply conduit 210 has a branched structure corresponding to this. Gas supply device 202
Helium gas sent from the air supply valves 106a-10
It is supplied to each purge space 250-254 via 6e, and the flow rate is individually controlled for each purge space 250-254.

Further, the gas supply device 202 and the air supply valve 106
A filter 211 for removing impurities contained in the helium gas is provided on the air supply line 210 between a to 106e.
Are arranged. In addition, instruments such as a pressure gauge for measuring the pressure in the passage and a concentration meter for measuring the concentration of the light-absorbing substance contained in the helium gas may be further provided on the air supply conduit 210. In addition, the gas supply source 201
It is also possible to omit the gas supply device 202 if the gas exhausted from has a sufficient pressure.

The pipe used for the air supply line 210 is a washed metal such as stainless steel, or a washed tetrafluoroethylene, tetrafluoroethylene-terefluoro (alkyl vinyl ether), or tetrafluoroethylene-hexafluoropropene. Chemically clean materials such as various polymers such as copolymers are used, and pipe joints are made of, for example, oil-free metal such as stainless steel or various polymers.

As the filter 211, a filter capable of removing the above-mentioned light absorbing substance by an action such as adsorption, absorption, or filtration is used. Specifically, it is mainly a dust (particles) such as a chemical filter that removes absorbing gas such as oxygen, or a HEPA filter or ULPA filter.
A filter or the like for removing is used. In addition, for example, ammonia, amine compounds, ionic compounds, siloxane, silazanes, silanol, and other silicon organic substances, plasticizers (phthalsan ester, etc.), flame retardants (phosphoric acid,
An activated carbon filter or a zeolite filter can be used as a filter for removing impurities such as chlorine-based substances.

A plurality of filters 211 may be arranged side by side on the air supply line 125. For example, by arranging a plurality of filters having different characteristics in series and arranging a filter having a higher purity specification on the downstream side, it becomes possible to use the filters efficiently. Also, by arranging the filters in parallel, it is possible to suppress the flow resistance due to the filters. Alternatively, it is possible to improve the workability of filter replacement by selectively passing gas through the filters arranged in parallel.

The exhaust device 203 generates, for example, a vacuum pressure, and through the exhaust pipe line 212, each of the purge spaces 250 to 25.
The gas in 4 is discharged. Each purging space 250
The gas discharged from ˜254 is discharged to the space outside the apparatus, for example. The gas discharged from each of the purge spaces 250 to 254 may be purified and reused as a purge gas. By reusing the gas, the consumption of the purge gas (helium gas in this example) can be reduced.

The temperature controller 204 controls the temperature of the helium gas supplied to the purge spaces 250 to 254 on the optical path to a predetermined value. In this example, each purge space 250-254
The temperature of the gas is higher than room temperature (20 to 25 ° C.), for example, 40 to 150, so that the saturated moisture content in the inside increases.
Control to ℃. The gas temperature may be constantly controlled or may be changed. When helium is used as the purge gas as in this example, it is preferable that the temperature control device is arranged near each casing.

The densitometers 205a-205e are, in this example,
It is installed in each of the purge spaces 250 to 254. As the densitometer, for example, an oxygen densitometer, a dew point meter as a water vapor densitometer, a densitometer such as a carbon dioxide sensor, or a composite sensor combining these sensors is adopted. As the densitometer, a device such as a mass spectrometer or a sensor that indirectly measures the concentration of the light-absorbing substance contained in the gas by passing an electric current and measuring the current value may be used.

In the gas supply system 200, high-purity helium gas is supplied to the purge spaces 250 to 254 on the optical path via the filter 211. As a result, the purging spaces 250 to 254 are filled with helium gas. At this time, based on the measurement results of the densitometers 205a to 205e, the concentration of the light-absorbing substance in each of the purge spaces 250 to 254 is a predetermined allowable concentration (for example, 10 p in volume ratio).
pm) or less, the amount of gas supplied to each purge space 250-254 is controlled via the air supply valves 106a-106e. Thereby, each purge space 250-2
Light absorbing material within 54 is reduced.

In this example, the temperature of helium gas is
The temperature controller 204 controls the temperature higher than room temperature (20 to 25 ° C.), for example, 40 to 150 ° C. As a result, the amount of saturated water in each of the purge spaces 250 to 254 increases, and the water contained in the spaces easily evaporates. Therefore, by discharging the gas containing the evaporated water from each of the purge spaces 250 to 254 by the exhaust device 203,
Water in the spaces 250 to 254 can be removed in a short time. Further, since the evaporation of water in the purge spaces 250 to 254 is promoted by supplying the gas having a temperature higher than room temperature, it is possible to reliably remove the water, which is the light absorbing substance, from the purge spaces 250 to 254.

The helium gas is purged in the space 250-
When supplying into 254, purge space 250-2
When 54 contains a large amount of absorbing gas such as air, the gas in the spaces 250 to 254 may be temporarily discharged by the exhaust device 203 before supplying the helium gas. As a result, the purge space 250 can be shortened in a shorter time.
The inside of ~ 254 can be replaced with helium gas which is a low absorption gas.

Therefore, in the exposure apparatus 10 of the present embodiment shown in FIG. 1, the space on the optical path of the exposure beam is filled with the low absorption gas and the light absorbing substance is water by providing the gas supply system 200. It is possible to reduce it reliably and in a short time. Therefore, the exposure beam which is vacuum ultraviolet light stably reaches the wafer with sufficient illuminance, the exposure process is performed with high accuracy, and the throughput is improved.

The timing of supplying the high temperature gas into the space on the optical path by the gas supply system may be only when the exposure apparatus is started up, or after the apparatus is started up and when the exposure processing is performed. Further, a difference may be provided in the temperature of the gas supplied when the apparatus is started up and when the exposure process is performed. For example,
When the apparatus is started up, a gas with a higher temperature is supplied to the space on the optical path to eliminate water in a short time, while at the time of exposure processing, a gas with a temperature lower than that is supplied to the space on the optical path. Examples of methods include stabilization.

The preferred embodiment of the present invention has been described above with reference to the accompanying drawings, but it goes without saying that the present invention is not limited to this example. It is obvious to those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea described in the claims, and of course, the technical scope of the present invention is also applicable to them. Be understood to belong to.

For example, in the above embodiment, an example in which a projection optical system is applied as an optical device has been described as a representative,
The optical device of the present invention is not limited to the projection optical system, but can be applied to other optical devices such as an illumination optical system.

Further, the high temperature gas may be supplied to all of the plurality of spaces on the optical path provided in the optical device, or the high temperature gas may be supplied only to the space where water is likely to remain.

Although the purge space is airtight, it does not necessarily have to be airtight. For example, the gas in the space may be kept in a desired state by keeping the atmospheric pressure in the space higher than the external atmospheric pressure. The members sandwiched between the plurality of purge spaces include the above-mentioned lens element and parallel flat plates such as mirrors. In particular, for short wavelength light such as vacuum ultraviolet light, a reflection optical system may be adopted, and the present invention is preferably used in such cases as well.

Further, in order to remove the light absorbing substance from the optical path, it is preferable to perform a treatment for reducing the amount of degassing from the surface of the structural material in advance. For example, (1) reduce the surface area of the structural material, (2) mechanically polish the surface of the structural material,
Electrolytic polishing, ball polishing, chemical polishing, or GBB (Glass Be
The surface roughness of the structural material is reduced by polishing with a method such as ads Blasting), and (3) ultrasonic cleaning, spraying fluid such as clean dry air, and vacuum heating degassing (baking). There are methods such as cleaning the surface, and (4) not installing an electric wire coating material containing a hydrocarbon or a halide, a sealing member (O-ring, etc.), an adhesive, etc. in the optical path space as much as possible.

A vacuum pump, a cryopump or the like is used as an exhaust device for generating a vacuum pressure. A cryopump is a type of vacuum pump that cools sorbent such as activated carbon or synthetic fluoride with a refrigerant such as nitrogen, and is a surface cooled to a cryogenic temperature (10-15K) in a vacuum (cryopanel). And place a gas (H ₂ ,
A gas other than He and Ne, such as N ₂ and Ar, is adsorbed to create a high vacuum.

Further, the casing (a cylindrical body or the like) forming the cover of the wafer operation unit from the illumination system chamber and the pipe for supplying the transparent gas are made of a material with a small amount of impurity gas (degas), such as stainless steel. It is desirable to use various polymers such as steel, tetrafluoroethylene, tetrafluoroethylene-terfluoro (alkyl vinyl ether), or tetrafluoroethylene-hexafluoropropene copolymer.

Further, it is desirable that the cable for supplying electric power to the driving mechanism (reticle blind, stage, etc.) in each housing is also covered with the above-mentioned material with less impurity gas (degassing).

Degas from the photosensitive material (photoresist) applied on the wafer contains a light-absorbing substance, which varies in amount and type depending on the type and temperature of the photosensitive material. Therefore, the amount and type of degassing from the photosensitive material may be investigated in advance, and the supply amount of the low absorptive gas may be adjusted depending on the photosensitive material. As a result, it is possible to surely remove the light-absorbing substance from the working distance portion, while suppressing the consumption amount of the generally expensive low-absorbing gas to the necessary minimum.

Further, it is obvious that the present invention can be applied not only to the scanning exposure type projection exposure apparatus but also to a collective exposure type (stepper type) projection exposure apparatus and the like. The projection optical system provided in these may be not only a catadioptric system but also a refraction system or a reflection system. Further, the magnification of the projection optical system is not limited to the reduction magnification, but may be equal magnification or enlargement.

In the present invention, the energy beam A
When rF excimer laser light (wavelength 193 nm) is used, or when Kr ₂ laser light (wavelength 146 nm), Ar ₂ laser light (wavelength 126 nm), YAG laser harmonics, or semiconductor laser harmonics has a wavelength of 200 nm ~ 100n
It can also be applied to vacuum ultraviolet light of about m.

Further, DFB (Distributed feedback) is used instead of the excimer laser, the F ₂ laser, or the like.
A single wavelength laser in the infrared or visible range emitted from a semiconductor laser or a fiber laser is amplified by a fiber amplifier doped with, for example, erbium (Er) (or both erbium and ytterbium (Yb)), You may use the harmonic wave which carried out wavelength conversion to the ultraviolet light using the optical crystal.

The application of the exposure apparatus is not limited to the exposure apparatus for semiconductor manufacturing, and for example, a liquid crystal exposure apparatus for exposing a liquid crystal display element pattern on a rectangular glass plate or a thin film magnetic head. It is also widely applicable to an exposure apparatus for manufacturing.

When a linear motor is used for the wafer stage or reticle stage, either an air levitation type using an air bearing or a magnetic levitation type using Lorentz force or reactance force may be used. Also, the stage may be a type that moves along a guide,
A guideless type without a guide may be used.

Further, as a stage driving device, a plane mode is used.
When using a magnet, one of the magnet unit (permanent magnet) and the armature unit may be connected to the stage, and the other of the magnet unit and the armature unit may be provided on the moving surface side (base) of the stage.

Further, the reaction force generated by the movement of the wafer stage is mechanically floored (ground) by using a frame member, as described in Japanese Patent Laid-Open No. 8-166475.
You may let me escape. The present invention can also be applied to an exposure apparatus having such a structure.

The reaction force generated by the movement of the reticle stage may be mechanically released to the floor (ground) by using a frame member, as described in JP-A-8-330224. The present invention can also be applied to an exposure apparatus having such a structure.

As described above, the exposure apparatus according to the present embodiment has various subsystems including the constituent elements recited in the claims of the present application, with a predetermined mechanical accuracy, electrical accuracy, and
It is manufactured by assembling so as to maintain optical accuracy. Before and after this assembly, adjustments to achieve optical precision for various optical systems, adjustments to achieve mechanical precision for various mechanical systems, and various electrical systems to ensure these various types of precision are made. Are adjusted to achieve electrical accuracy. The process of assembling the exposure apparatus from the various subsystems includes mechanical connection, electrical circuit wiring connection, air pressure circuit pipe connection, and the like between the various subsystems. It goes without saying that there is an individual assembly process for each subsystem before the assembly process from these various subsystems to the exposure apparatus. When the process of assembling the various subsystems into the exposure apparatus is completed, comprehensive adjustment is performed to ensure various accuracies of the exposure apparatus as a whole. It is desirable that the exposure apparatus be manufactured in a clean room where the temperature and cleanliness are controlled.

Then, the wafer thus exposed is subjected to a developing process, a pattern forming process, a bonding process, a packaging process and the like to manufacture an electronic device such as a semiconductor element.

[0062]

According to the optical device of the present invention, the temperature of the predetermined gas supplied to the space on the optical path is controlled so that the saturated water content in the space increases, and the evaporation of water in the space is prevented. By promoting it, the water contained in the space on the optical path is eliminated in a short time. Therefore, it is possible to surely reduce the light absorbing substance in the space including water.

Further, according to the exposure apparatus of the present invention, the water contained in the space on the optical path is eliminated in a short time, and the light-absorbing substance in the space is reliably reduced including the water. The exposure accuracy can be improved.

[Brief description of drawings]

FIG. 1 is a diagram showing an overall configuration of a reduction projection exposure apparatus for manufacturing a semiconductor device according to an embodiment including an optical device according to the present invention.

FIG. 2 is a diagram showing an example of a configuration of a gas supply system that supplies a purge gas to each space on an optical path of an exposure beam.

[Explanation of symbols]

IL exposure light (energy beam) R reticle (mask) W wafer (substrate) PL projection optical system (optical device) 21 Illumination optical system (optical device) 200 gas supply system 204 Temperature control device 250-254 Purge space

Claims (3)

[Claims] 1. In an optical device having a space formed on the optical path of an energy beam and supplied with a predetermined gas, the temperature of the predetermined gas is controlled so that the amount of saturated moisture in the space increases. An optical device comprising a temperature control device. 2. The optical device according to claim 1, wherein the temperature control device controls the temperature of the predetermined gas to a temperature higher than room temperature. 3. The illumination optical system for illuminating a mask having a pattern formed thereon with an energy beam, and at least one of a projection optical system for transferring the pattern of the mask onto a substrate, according to claim 1 or 2. An exposure apparatus comprising the optical device of.