JPH11195583A - Aligner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an aligner for performing exposure to a short wavelength light, while preventing deterioration of the intensity of an exposing light and generation of ozone. SOLUTION: This aligner 100 is provided with a light source 2 which emits an illumination light for exposure, an illumination optical system 110 by which the illumination light is projected onto an a reticle R, a reticle stage 18 which retains the reticle R, a projection optical system PL by which the illumination light emitted from the reticle R is projected onto a wafer W, and a wafer stage 22 which retains the wafer W. The device main body, containing at least a part of the illumination optical system 110, the projection optical system PL, the reticle stage 18 and the surface plate 23 of the wafer stage 22, is covered by a housing 102, and the inside of the housing 102 is formed into a device structure having an atmosphere, from which ozon is hardly generated by the passage of illumination light.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an exposure apparatus used for manufacturing, for example, a semiconductor device, an image pickup device, a liquid crystal display device, a thin film magnetic head, and other micro devices. The present invention relates to an exposure apparatus that performs exposure using light of the type described above and that can suppress a decrease in intensity of exposure light and generation of ozone.

[0002]

2. Description of the Related Art In a photolithography process for manufacturing a semiconductor device or the like, an exposure apparatus that exposes a pattern image of a photomask (including a reticle) onto a photosensitive substrate via a projection optical system is used. In recent years, semiconductor integrated circuits have been developed in the direction of miniaturization, and in photolithography processes, the wavelength of photolithography light sources has been reduced.

However, vacuum ultraviolet rays, especially 250 n
m, for example, a KrF excimer laser (wavelength: 248 nm), an ArF excimer laser (wavelength: 19 nm).
3 nm), F ₂ laser (wavelength 157 nm), or YA
When using light such as a harmonic such as a G laser as exposure light, there have been problems such as a reduction in light intensity and generation of harmful ozone gas due to absorption by oxygen and the like.

Therefore, conventionally, in an exposure apparatus having a light source such as an ArF excimer laser, only the optical path portion is sealed, and the gas inside is replaced with a gas containing no oxygen, such as nitrogen, so that the light transmittance is reduced. (See Japanese Patent Laid-Open No. 6-260385).

[0005]

However, the sealing of only the optical path portion is performed by moving parts such as a wafer stage and a mask stage as in a so-called step-and-repeat (repeated batch exposure for each step) type exposure apparatus. However, it is difficult for an apparatus existing in the optical path, and it is inevitable that exposure light is partially exposed to air.

Further, the structure for sealing the projection lens, the illumination lens, and the like also complicates the mechanism, and is a factor that lowers the reliability and the degree of freedom in design.

SUMMARY OF THE INVENTION The present invention has been made in view of such circumstances, and in particular, in an exposure apparatus for performing exposure using light having a short wavelength, an exposure apparatus capable of suppressing a decrease in intensity of exposure light and generation of ozone. The purpose is to provide.

[0008]

In the following description, the present invention will be described with reference to the member codes shown in the drawings showing the embodiments. However, the present invention is not limited to the members shown in the drawings attached with.

[0009] exposure apparatus according to a first aspect of claim 1 the present invention (corresponding to claim 1)
A light source (2) that emits illumination light for exposure, an illumination optical system (110) that irradiates the mask (R) with the illumination light, and a first holding member (18) that holds the mask (R). A projection optical system (PL) for projecting illumination light emitted from the mask (R) onto a photosensitive substrate (W), and a second holding member (22) for holding the photosensitive substrate (W). An exposure apparatus comprising: an apparatus main body including at least a part of the illumination optical system (110), the projection optical system (PL), and the first and second holding members (18, 22). The case (102) is covered with a body (102), and the housing (102) is characterized in that it has a closed structure in which the inside of the case (102) serves as an atmosphere for reducing the rate of ozone generation due to the passage of the illumination light.

In this exposure apparatus, the illumination optical system (110)
, The projection optical system (PL), and the first and second holding members (18, 22) are covered with a housing (102), and the housing has the interior of the illumination light. Since the airtight structure has an atmosphere in which the rate of ozone generation due to passage is reduced, it has the following effects.

That is, in this exposure apparatus (100),
Compared to a conventional exposure apparatus in which only the optical path portion has a closed structure, the entire apparatus body is covered with a housing (102) and has a specific internal atmosphere, so that the first and second holding members (movable parts) are provided. 18 and 22), exposure of the illumination light for exposure to air can be prevented, and generation of ozone due to passage of the illumination light for exposure can be greatly reduced.

In addition, the first and second holding members (18, 22), which are movable parts, can prevent the illumination light from being exposed to the air, so that the light intensity may be reduced due to the influence of absorption by the air. Can be prevented. In particular, vacuum ultraviolet light, particularly light having a wavelength shorter than 250 nm, for example, a KrF excimer laser (wavelength 248 nm), an ArF excimer laser (wavelength 193 nm), and an F ₂ laser (wavelength 15
7 nm) or a short-wavelength light such as a higher harmonic wave such as a YAG laser is used as exposure light. However, problems such as a decrease in light intensity and generation of harmful ozone gas due to absorption by oxygen. Can be effectively eliminated.

Further, in the exposure apparatus according to the first aspect of the present invention, since the projection optical system and the illumination optical system are not hermetically sealed, confidentiality is taken into consideration when designing the projection optical system and the illumination optical system. This eliminates the need for designing and manufacturing, and makes these manufacturing easier.

Further, the exposure apparatus according to the first aspect of the present invention is different from the technique disclosed in Japanese Patent Application Laid-Open No. 6-260385 in that a gas other than air, such as nitrogen gas, is not blown to the vicinity of the photosensitive substrate. At the same time, since these gases do not leak, a decrease in the oxygen partial pressure in the working environment can be prevented.

[0015] In an exposure apparatus according to a first aspect of claim 2 the present invention, the illumination light has an oscillation spectrum in 150 to 250 nm, to the housing interior below the vacuum 1 × 10 ^-4 Torr It is preferable to further include a vacuum device (125) (corresponding to claim 2).

In particular, when the illuminating light has an oscillation spectrum of 150 to 250 nm, there are problems such as a decrease in light intensity and generation of harmful ozone gas due to absorption by oxygen and the like. In one aspect, these problems can be effectively solved by setting the inside of the housing (102) to a vacuum state of 1 × 10 ⁻⁴ Torr or less.

[0017] In an exposure apparatus according to a first aspect of claim 3 the present invention, a sensor for detecting the oxygen concentration of the casing (102) (118)
And a gas supply device (120) for supplying an inert gas into the housing according to the output of the sensor (corresponding to claim 3).

In the exposure apparatus having such a configuration, when the oxygen concentration inside the housing rises above a predetermined value, it can be detected by the sensor (118). Therefore,
If the oxygen concentration inside the housing rises to a predetermined value or more for some reason, an inert gas is supplied into the housing according to the output of the sensor (118), so that the influence of oxygen absorption and the like is obtained. Thus, problems such as a decrease in light intensity and generation of harmful ozone gas can be effectively solved.

In the present specification, the term "inert gas" is used to include nitrogen gas.

(4) In the exposure apparatus according to the first aspect of the present invention, the illumination light has an oscillation spectrum at 150 to 200 nm, and the inert gas is, for example, helium (corresponding to claim 4). ).

In particular, when the illuminating light has an oscillation spectrum of 150 to 250 nm, there are problems such as a decrease in light intensity and generation of harmful ozone gas due to absorption by oxygen and the like. In one aspect of the invention, these problems can be effectively solved by using, for example, helium gas as the inert gas and enclosing it in the housing.

[0022] In an exposure apparatus according to a first aspect of claims 5-7 present invention, further comprising a temperature adjustment device for cooling (136, 138) at least one optical element of the illumination optical system and the projection optical system Preferably (corresponding to claim 5).

In the exposure apparatus according to the first aspect of the present invention, the temperature adjusting device includes a fluid (1) whose temperature is adjusted inside a holding device that holds the at least one optical element.
34) is preferably provided (corresponding to claim 6).

In particular, when the inside of the housing is evacuated, heat generated by light absorption of a portion of the optical element such as a lens to which the illumination light for exposure is irradiated is not transmitted by an environmental gas such as air as in the prior art. Requires a temperature control device for cooling. Therefore, in one embodiment of the present invention, a change in optical conditions due to heat of the optical element can be suppressed by cooling the optical element using the temperature adjustment device (136). Further, as another embodiment of the temperature adjusting device, an injection device (138) for blowing a gas such as a dilute inert gas whose temperature has been adjusted for cooling toward the optical element at the time of non-exposure can be used. However, spraying from the injection device is preferably performed during non-exposure,
At the time of exposure, it is preferable to adjust the degree of vacuum so that a vacuum state of 1 × 10 ⁻⁴ Torr or less is obtained.

Incidentally, even if the inside of the housing is not evacuated,
It is important to keep the optical element at a constant temperature, and by using a temperature adjusting device to cool the optical element, a change in optical conditions due to heat of the optical element can be suppressed.

For example, in the exposure apparatus according to the first aspect of the present invention, the casing is filled with an inert gas.
The temperature control device may include an injection device (138) for blowing the same temperature-controlled gas as the inert gas to the at least one optical element (corresponding to claim 7).

In the exposure apparatus according to the first aspect of the present invention, from the viewpoint of preventing heat generation of the optical element, a glass material having a high transmittance, such as fluorite, may be used, or the energy of the illumination light for exposure may be reduced. May be lowered. Alternatively, it is also preferable to use an optical element such as fluorine-doped quartz which has little optical influence on heat generation.

The exposure apparatus according to the second aspect of claim 8 the invention (corresponding to claim 8)
Is a light source (2) for emitting illumination light for exposure, an illumination optical system (110) for irradiating the illumination light to a mask, and projecting illumination light emitted from the mask onto a photosensitive substrate (W). In an exposure apparatus having a projection optical system (PL), a casing (160, 1) in which the illumination optical system (110) and the projection optical system (PL) are respectively filled with a first gas.
62) a gas supply mechanism (150) for flowing a second gas into the space between the projection optical system (PL) and the photosensitive substrate (W) during the exposure of the photosensitive substrate (W). It is characterized by having.

In the exposure apparatus according to the second aspect of the present invention,
A casing (160, 162) in which the illumination optical system (110) and the projection optical system (PL) are respectively filled with a first gas.
And a gas supply mechanism (15) for flowing a second gas into a space between the projection optical system and the photosensitive substrate during exposure of the photosensitive substrate.
0), the following operations are provided.

That is, in the exposure apparatus (100a), a necessary minimum portion is formed by the casings (160, 162).
In the casing, the exposure of the illumination light for exposure to air can be prevented, and the generation of ozone due to the passage of the illumination light for exposure can be greatly reduced. In addition, a decrease in light intensity can be suppressed.

Further, in the holding portion of the photosensitive substrate (W), which is a movable portion, during the exposure of the photosensitive substrate (W), a first space is formed between the projection optical system (PL) and the photosensitive substrate (W). By flowing the two gases, the exposure of the illumination light to air can be reduced as much as possible, and the reduction of light intensity and the generation of ozone due to the influence of air absorption can be suppressed as much as possible. Especially,
Vacuum ultraviolet light, particularly light having a wavelength shorter than 250 nm, for example, KrF excimer laser (wavelength 248 nm), ArF
Even when short-wavelength light such as an excimer laser (wavelength 193 nm), F ₂ laser (wavelength 157 nm), or a higher harmonic wave such as a YAG laser is used as exposure light, the light intensity is reduced due to absorption by oxygen and the like. And the problem of generating harmful ozone gas can be effectively solved.

Further, in the exposure apparatus according to the second aspect of the present invention, a necessary minimum portion is formed in a casing (16
0,162), there is an advantage that the entire exposure apparatus does not have a large structure. Further, it is not necessary to adjust the atmosphere inside the housing every time the photosensitive substrate (W) is replaced, so that the throughput of the exposure operation is improved.

[0033] In an exposure apparatus according to the second aspect of claim 9 present invention, the first
An inert gas other than nitrogen may be used as the gas, and a nitrogen gas may be used as the second gas (corresponding to claim 9). As the first gas, a relatively expensive inert gas such as helium gas is used, which is excellent in the action of not reducing the light intensity and generating harmful ozone gas because it is sealed in the casing. This is because it is economical and safe to use relatively inexpensive nitrogen contained in air as the second gas also discharged.

[0034] In an exposure apparatus according to the second aspect of claim 10 present invention, the illumination light has an oscillation spectrum in 150 to 200 nm, the first gas is helium, the second gas is a nitrogen Preferably (corresponding to claim 10).

In particular, when the illumination light has an oscillation spectrum of 150 to 250 nm, there are problems such as a decrease in light intensity and generation of harmful ozone gas due to the influence of absorption by oxygen and the like. In one aspect, the first
These problems can be effectively solved by using helium as a gas and using nitrogen as a second gas.

[0036] In an exposure apparatus according to the second aspect of claim 11 present invention, the mask (R) the illumination optical system disposed mask stage (18) for holding (110) and said projection optical system (PL )
It is preferable to flow the second gas into a space between the second gas and the second gas.

The projection optical system (PL) is also a movable part between the illumination optical system (110) on which the mask stage (18) for holding the mask (R) is arranged and the projection optical system (PL). PL) and the photosensitive substrate (W) for the same reason as when the second gas is caused to flow in the space, by flowing the second gas, it is possible to reduce exposure of the illumination light to air as much as possible. Generation can be suppressed and a decrease in light intensity can be suppressed.

12. An exposure apparatus according to a second aspect of the present invention, wherein the mask stage (18) for holding the mask (R) is provided in the first stage.
It can be arranged in the casing (160, 162) filled with gas (corresponding to claim 12).

The photosensitive substrate (W) is a movable part between the illumination optical system (110) and the projection optical system (PL) where the mask stage (18) for holding the mask (R) is arranged. Therefore, even if the mask stage is arranged in the casing filled with the first gas, the size of the entire apparatus is not so large.

The magnification of the exposure apparatus according to the first and second aspects of the claim 13 the present invention, in order to transfer the pattern of the mask (R) on the photosensitive substrate, the projection optical system (PL) A drive device (12, 13) for synchronously moving the mask (R) and the photosensitive substrate (W) at a speed ratio according to the following (corresponding to claim 13).

An exposure apparatus provided with such a driving device (12, 13) is a so-called step-and-scan type exposure apparatus. An exposure apparatus of this type uses a mask (R) in a state where a part of a pattern on a mask such as a reticle is reduced and exposed on a photosensitive substrate through a projection optical system.
And the photosensitive substrate (W) are synchronously moved with respect to the projection optical system (PL), so that a reduced image of the pattern on the mask (R) is sequentially transferred to each shot area of the photosensitive substrate. Device. The exposure apparatus of this type has an advantage that the area of the pattern to be transferred can be enlarged without increasing the load on the projection optical system as compared with the exposure apparatus of the so-called step-and-repeat type.

In a so-called step-and-scan exposure apparatus, the movable portion is large because the photosensitive substrate (W) and the mask (R) move synchronously during exposure, but the first aspect of the present invention is as follows. In the exposure apparatus according to (1), since the entire apparatus body is covered, exposure of the illumination light for exposure to air can be prevented, and generation of ozone due to passage of the illumination light for exposure can be greatly reduced. In addition, the first and second holding members (18, 22), which are movable portions, can also prevent the illumination light from being exposed to the air, so that the light intensity can be prevented from being reduced due to the influence of absorption by the air. Can be.

In the exposure apparatus according to the second aspect of the present invention,
Since the relatively large movable portion is not covered with the housing, it is possible to prevent the entire apparatus from becoming large. Nevertheless, by flowing the second gas into the space between the projection optical system and the photosensitive substrate, the generation of ozone due to the passage of the illumination light for exposure can be greatly reduced, and the light intensity decreases. Can also be prevented.

[0044] In an exposure apparatus according to the first and second aspects of Claim 14 present invention, the illumination light may be a F ₂ laser (claim 1
4). In particular, since the wavelength of the F ₂ laser is as short as 157 nm, in an ordinary air atmosphere, there are problems such as a decrease in light intensity and generation of harmful ozone gas due to absorption by oxygen and the like. However, the exposure apparatus according to the first and second aspects of the present invention can effectively solve these problems.

[0045]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below based on embodiments shown in the drawings.

FIG. 1 is an overall configuration diagram of an exposure apparatus according to an embodiment of the present invention, FIG. 2 is a schematic view of the exposure apparatus main body shown in FIG. 1, FIG. 3 is a schematic sectional view of a projection optical system shown in FIG. FIG.
FIGS. 5A to 5D are explanatory diagrams showing a relationship between an illumination region and an exposure region of a projection optical system and a modification of the exposure region; FIGS.
FIG. 6 is a schematic sectional view showing a lens holding mechanism used in an exposure apparatus according to another embodiment of the present invention, and FIG. 7 is a main part configuration diagram of an exposure apparatus according to still another embodiment of the present invention.

First Embodiment As shown in FIGS. 1 and 2, a projection exposure apparatus 100 according to an embodiment of the present invention is an exposure apparatus of a so-called step-and-scan system, and is provided on a reticle R as a mask. The reticle R and the wafer W are synchronously moved with respect to the projection optical system PL in a state where a part of the pattern is reduced and projected through the projection optical system PL onto the wafer W coated with a resist as a photosensitive substrate. By doing so, a reduced image of the pattern on the reticle R is sequentially transferred to each shot area of the wafer W.

In this embodiment, as shown in FIG. 1, in a projection exposure apparatus of such a step-and-scan method, a main part of the apparatus main body except for a light source 2 of the apparatus main body is covered with a casing 102. The inside of the housing 102 has a sealed structure that provides an atmosphere that reduces the rate of generation of ozone due to the passage of illumination light. In this embodiment, 10
Reference numeral 2 denotes an airtight chamber made of, for example, an electromagnetic shielding material. The housing 102 is also provided with a door for exchanging the wafer W and the reticle R. Further, the illumination light for exposure from the light source 2 is
A light guide path 114 for guiding to zero is also formed. Light guide path 1
14 is not particularly limited, but transparent glass or the like is used. When the light source 2 is installed away from the apparatus main body, for example, when the light source 2 is arranged under the floor of a clean room where the apparatus main body is installed, the light emitted from the illumination optical system 110 and the light source 2 is emitted. A light transmitting system including a beam matching unit such as a mirror for adjusting the positional relationship with the exposure illumination system is housed in a housing, and the inside thereof is made to have the same atmosphere as the housing 102.

As shown in FIG. 1, in this embodiment, the main part of the exposure apparatus main body accommodated in the housing 102 is
An illumination optical system 110 for irradiating the reticle R with illumination light for exposure from the light source 2, a reticle stage 18 (see FIG. 2) as a first holding member for holding the reticle R, a projection optical system PL, and a wafer And a surface plate 23 of a wafer stage 22 (see FIG. 2) as a second holding member for holding W.

First, the illumination optical system 110 will be described with reference to FIG. As shown in FIG. 2, the illumination optical system 110 of the present embodiment includes a deflecting mirror 3, a first illumination system 4, a switching revolver 5, a switching device 6, a beam splitter 8,
It has an integrator sensor 9, a second illumination system 10, an illumination field stop system 11, a third illumination system 14, and the like. In the present embodiment, as shown in FIG. 1, the light source 2 is disposed outside the housing 102. The light source 2 is not particularly limited, but in the present embodiment, a KrF excimer laser (wavelength 24
8 nm), ArF excimer laser (wavelength 193 nm),
F ₂ laser (wavelength 157 nm) is a short-wavelength laser light source than 250nm, such as.

The operation of the illumination optical system 110 will be described. As shown in FIG. 2, the illumination light IL composed of the pulse laser light emitted from the laser light source 2 whose light emission state has been controlled by the exposure control device 1 is deflected by a deflecting mirror. The light is deflected by 3 and reaches the first illumination system 4.

The first illumination system 4 includes a beam expander,
It includes a light quantity variable mechanism, an illumination switching mechanism for switching the quantity of illumination light when the coherence factor (so-called σ value) of the illumination optical system is changed, and a fly-eye lens. A secondary light source distributed in a plane shape of the illumination light IL is formed on the exit surface of the first illumination system 4, and switching for an illumination system aperture stop for variously switching illumination conditions is performed on the secondary light source formation surface. A revolver 5 is arranged.
On the side surface of the switching revolver 5, a normal circular aperture stop, an aperture stop for so-called deformed illumination composed of a plurality of apertures eccentric from the optical axis, a ring-shaped aperture stop, and a small σ value composed of a small circular aperture are provided. An aperture stop or the like is formed, and a desired illumination system aperture stop (σ stop) can be arranged on the exit surface of the first illumination system 4 by rotating the switching revolver 5 via the switching device 6. I have. When the illumination system aperture stop is switched in such a manner,
In synchronization with the switching device 6, the illumination switching mechanism in the first illumination system 4 is switched so that the light amount becomes maximum.

The operation of the switching device 6 is similar to that of the exposure control device 1.
The operation of the exposure control apparatus 1 is controlled by a main controller 7 that controls the overall operation of the apparatus.

The illumination light IL transmitted through the illumination system aperture stop set by the switching revolver 5 enters the beam splitter 8 having a large transmittance and a small reflectance, and the illumination light reflected by the beam splitter 8 is converted into a photo The light is received by an integrator sensor 9 including a photoelectric detector such as a diode. A detection signal obtained by photoelectrically converting the illumination light by the integrator sensor 9 is supplied to the exposure control device 1. The relationship between the detection signal and the exposure amount on the wafer is measured and stored in advance, and the exposure control device 1 monitors the integrated exposure amount on the wafer from the detection signal. The detection signal is also used to normalize output signals of various sensor systems using the illumination light IL for exposure.

Illumination light IL transmitted through beam splitter 8
Illuminates an illumination field stop system (reticle blind system) 11 via a second illumination system 10. This illumination field stop system 1
The arrangement surface 1 is conjugate with the entrance surface of the fly-eye lens in the first illumination system 4, and the illumination field stop system 11 is illuminated in an illumination area substantially similar to the cross-sectional shape of each lens element of the fly-eye lens. You. The illumination field stop system 11 is divided into a movable blind and a fixed blind. The fixed blind is a field stop having a fixed rectangular opening. The movable blind is movable in the reticle scanning direction and the non-scanning direction and can be opened and closed. Are two pairs of movable blades. The fixed blind determines the shape of the illumination area on the reticle, and the movable blind gradually opens and closes the cover of the opening of the fixed blind at the start and end of scanning exposure. by this,
Irradiation light is prevented from irradiating an area other than the original shot area on the wafer.

The operation of the movable blind in the illumination field stop system 11 is controlled by a drive unit 12. When the stage control unit 13 performs synchronous scanning of a reticle and a wafer as described later, the stage control unit 13
Drives the movable blind in the scanning direction in synchronization with the driving device 12. The illumination light IL that has passed through the illumination field stop system 11 illuminates a rectangular illumination area 15 on the pattern surface (lower surface) of the reticle R with a uniform illumination distribution via a third illumination system 14. The arrangement surface of the fixed blind of the illumination field stop system 11 is conjugate with the pattern surface of the reticle R, and the shape of the illumination area 15 is defined by the opening of the fixed blind.

In the following, the X axis is taken perpendicular to the plane of FIG. 2 in the plane parallel to the pattern plane of the reticle R, the Y axis is taken parallel to the plane of FIG. 2, and the Z axis is taken perpendicular to the pattern plane of the reticle R. Take and explain. At this time, the illumination area 1 on the reticle R
5 is a rectangular area long in the X direction.
The reticle R is in the + Y direction with respect to the illumination area 15 or-
Scanning is performed in the Y direction. That is, the scanning direction is set in the Y direction.

The pattern in the illumination area 15 on the reticle R is projected through a telecentric projection optical system PL on both sides (or one side on the wafer side) to a projection magnification β (β is, for example, 1 /.
(4, 1/5, etc.), and is image-formed and projected on the exposure region 16 on the surface of the wafer W coated with the photoresist.

The reticle R shown in FIG. 1 is held on a reticle stage 17 as shown in FIG. 2, and the reticle stage 17 is mounted on a guide extending in the Y direction on a reticle support 18 via an air bearing. Is placed. The reticle stage 17 can scan the reticle support 18 in the Y direction at a constant speed by a linear motor, and has an adjustment mechanism that can adjust the position of the reticle R in the X direction, the Y direction, and the rotation direction (θ direction). . A moving mirror 19m fixed to the end of the reticle stage 17 and a laser interferometer (not shown except for the Y axis) 19 fixed to a column (not shown) are used to move the reticle stage 17 (reticle R) in the X and Y directions. The position in the direction is always measured with a resolution of about 0.001 μm, the rotation angle of the reticle stage 17 is also measured, and the measured value is supplied to the stage control device 13. The stage control device 13 responds to the supplied measured value. Thus, the operation of a linear motor or the like on the reticle support 18 is controlled.

On the other hand, as shown in FIG. 2, the wafer W shown in FIG. 1 is held on a sample stage 21 via a wafer holder 20, and the sample stage 21 is mounted on a wafer stage 22.
The wafer stage 22 is mounted on a guide on the surface plate 23 via an air bearing. The wafer stage 22 is configured to be capable of scanning at a constant speed in the Y direction and stepping movement on the surface plate 23 by a linear motor, and also capable of stepping movement in the X direction. Further, a Z stage mechanism for moving the sample table 21 in a predetermined range in the Z direction in the wafer stage 22,
In addition, a tilt mechanism (leveling mechanism) for adjusting the inclination angle of the sample table 21 is incorporated.

Moving mirror 2 fixed to the side of sample stage 21
4 m, and the position of the sample table 21 (wafer W) in the X and Y directions is always 0.001 μm by a laser interferometer (not shown except for the Y axis) 24 fixed to a column (not shown).
At the same time, the rotation angle of the sample table 21 is measured. The measured value is supplied to the stage control device 13, and the stage control device 13 controls the operation of the linear motor for driving the wafer stage 22 and the like according to the supplied measured value.

At the time of scanning exposure, an exposure start command is sent from the main controller 7 to the stage controller 13, and the stage controller 13 moves the reticle R via the reticle stage 17 in the Y direction at a speed V _2. in synchronization with the scanning, it scans the wafer W via the wafer stage 22 at a velocity V _W in the Y direction. Reticle R to wafer W
The scanning speed V _W of the wafer _W is β
It is set to · V _2.

The projection lens system PL shown in FIG. 1 is actually held in the upper plate of a U-shaped column 25 planted on the surface plate 23 as shown in FIG. . And
A slit image or the like is projected obliquely onto a plurality of measurement points on the surface of the wafer W on the side surface in the X direction of the projection optical system PL, and corresponds to positions (focus positions) in the Z direction at the plurality of measurement points. An oblique incidence multipoint autofocus sensor (hereinafter, referred to as an “AF sensor”) that outputs a plurality of focus signals.
26) are disposed. Multi-point AF sensor 26
Are supplied to the focus / tilt control device 27 and the focus / tilt control device 2
In step 7, the focus position and the inclination angle of the surface of the wafer W are obtained from the plurality of focus signals, and the obtained results are supplied to the stage control device 13.

The stage controller 13 adjusts the supplied focus position and tilt angle in the wafer stage 22 such that the supplied focus position and tilt angle match the focus position and tilt angle of the imaging plane of the projection optical system PL which are determined in advance. The Z stage mechanism and the tilt mechanism are driven by a servo system.
As a result, even during the scanning exposure, the surface in the exposure region 16 of the wafer W is controlled so as to match the imaging plane of the projection optical system PL by the autofocus method and the autoleveling method.

Further, an off-axis type alignment sensor 28 is fixed to a side surface of the projection optical system PL in the + Y direction.
The position detection of the alignment wafer mark attached to each shot area of the wafer W is performed by 8, and a detection signal is supplied to the alignment signal processing device 29.
The measured value of the laser interferometer 24 is also supplied to the alignment signal processing device 29, and the alignment signal processing device 29 calculates the stage coordinate system (X, Y) of the wafer mark to be detected from the detection signal and the measured value of the laser interferometer 24. ) Is calculated and supplied to the main controller 7. The stage coordinate system (X, Y) refers to a coordinate system determined based on the X and Y coordinates of the sample table 21 measured by the laser interferometer 24. The main controller 7 obtains array coordinates in the stage coordinate system (X, Y) of each shot area on the wafer W from the coordinates of the supplied wafer mark, and supplies the coordinates to the stage controller 13. Controls the position of the wafer stage 22 when performing scanning exposure on each shot area based on the supplied array coordinates.

The reference mark member F is placed on the sample table 21.
M is fixed, and on the surface of the reference mark member FM, various reference marks serving as a position reference of the alignment sensor, a reference reflection surface serving as a reference of the reflectance of the wafer W, and the like are formed. Then, the wafer W is placed on the upper end of the projection optical system PL.
A reflected light detection system 30 for detecting a light beam and the like reflected from the side via the projection optical system PL is attached, and the reflected light detection system 3
The detection signal of “0” is supplied to the self-measurement device 31. Under the control of the main controller 7, the self-measuring device 31 monitors the amount of reflection (reflectance) of the wafer W, measures uneven illuminance, measures an aerial image, and the like, as described later.

Next, the configuration of the projection optical system PL shown in FIGS. 1 and 2 will be described in detail with reference to FIG.

As shown in FIG. 3, the projection optical system PL is mechanically composed of four parts: a first objective section 41, an optical axis turning section 43, an optical axis deflecting section 46, and a second objective section 52. Have been. Then, the concave mirror 4 is placed in the optical axis turning portion 43.
5 are arranged.

When a broadened laser beam is used as the illumination light IL, the amount of light can be increased even with the same power supply power, the throughput can be increased, and the coherence is reduced to reduce the adverse effect of interference. The advantage is that
However, when ultraviolet light such as KrF excimer laser light or ArF excimer laser light is used, the glass material that can be used as a refractive lens in the projection optical system PL is limited to quartz, fluorite, or the like. It is difficult to design the system alone. Therefore, in the embodiment, broadband achromatism is performed by using a reflective optical system and a refractive optical system that do not generate chromatic aberration like a concave mirror. Note that the reflection optical system is generally a one-to-one (actual magnification) optical system, and when performing a reduced projection such as 1/4 or 1/5 as in this embodiment, the following is required. As described above, the configuration requires a special device.

That is, the first objective section 41 is disposed immediately below the reticle R, and the first objective section 41 is placed in the lens barrel 42 from the reticle R side through the lenses L1, L2, L through the lens frame.
3, L4 is fixed. And the lens barrel 42
The lens barrel 44 of the optical axis turning part 43 is disposed below the lens barrel 47 of the optical axis deflecting part 46, and the lenses L11 and L1 are sequentially placed in the lens barrel 44 from the reticle R side via the lens frame.
, L20, L21 and the concave mirror 45 are fixed. The first objective section 41 and the optical axis turning section 43 are coaxial, and the optical axis is the optical axis AX1. The optical axis AX1 is perpendicular to the pattern surface of the reticle R.

At this time, in the lens barrel 47 of the optical axis deflecting section 46 between the lens barrel 42 and the lens barrel 44, a position decentered in the + Y direction from the optical axis AX1 in the + Y direction with respect to the optical axis AX1. A small mirror 48 having a reflective surface inclined at approximately 45 ° is arranged. In addition, the small mirror 48
The lenses L31 and L32 and the correction optical system 4 are sequentially arranged in the Y direction.
9 and a beam splitter 50. The optical axis AX2 of the optical axis deflecting unit 46 is orthogonal to the optical axis AX1, and the reflecting surface of the beam splitter 50 is inclined at approximately 45 ° to the optical axis AX2 so as to be orthogonal to the reflecting surface of the small mirror 48. The beam splitter 50 is a high-reflectance beam splitter having a transmittance of about 5% and a reflectivity of about 95%, and a method of using a light beam transmitted through the beam splitter 50 will be described later. Then, the correction optical system 49 has the optical axis A
It is composed of a lens group or the like that can finely move in the direction along X2 and that can finely adjust the tilt angle with respect to a plane perpendicular to the optical axis AX2. The position and tilt angle of the correction optical system 49 are controlled by the imaging characteristic correction device 51. ing. The operation of the imaging characteristic correction device 51 is controlled by the main control device 7 in FIG. The position where the correction optical system 49 is arranged is a position almost conjugate with the pattern surface of the reticle R, and can mainly correct distortion such as a magnification error.

The optical axis AX2 is set to the beam splitter 50.
The lens barrel 53 of the second objective section 52 is arranged so as to be in contact with the lens barrel 47 in the direction in which the beam splitter 50 is bent.
The lens L4 is inserted into the lens barrel 53 in order from the side via the lens frame.
, L52, L42, L43,...
The bottom surface of 2 faces the surface of wafer W. The optical axis AX3 of the second objective section 52 is parallel to the optical axis AX1 of the first objective section 41 and the optical axis turning section 43, and the optical axis deflecting section 4
6 is orthogonal to the optical axis AX2.

In this case, the rectangular illumination area 15 on the reticle R by the illumination light IL is set at a position decentered from the optical axis AX1 in the −Y direction, and the illumination light passing through the illumination area 15 (hereinafter referred to as “image forming light flux”). ) Passes through the lenses L1, L2,..., L4 in the first objective section 41, passes through the inside of the lens barrel 47 of the optical axis deflecting section 46, and enters the optical axis turning section 43. An image forming light beam incident on the optical axis turning section 43 passes through lenses L11, L12,.
, And reflected by the concave mirror 45 and condensed by the concave mirror 45, passes through the lenses L21, L20,..., L12, and L11 again and is deflected in the + Y direction by the small mirror 48 in the lens barrel 47 of the optical axis deflecting unit 46. You.

In the optical axis deflecting unit 46, the image forming light beam reflected by the small mirror 48 is incident on the beam splitter 50 via the lenses L31 and L32 and the correction optical system 49. At this time, an image (intermediate image) of substantially the same size as the pattern in the illumination area 15 on the reticle R is formed near the beam splitter 50 inside the lens barrel 47. Therefore, a combining system including the first objective section 41 and the optical axis turning section 43 is referred to as an “actual magnification optical system”. -Z with beam splitter 50
The image-forming light beam deflected in the direction is directed to the second objective unit 52, where the image-forming light beam is transmitted to the wafer W via lenses L41, L42, ..., L51, L50.
A reduced image of the pattern in the illumination area 15 on the reticle R is formed in the upper exposure area 16. Therefore, the second objective unit 52
Is also called a “reduction projection system”.

As described above, the illumination area 1 on the reticle R
The imaging light flux that has passed through the lens 5 substantially in the −Z direction passes through the first objective unit 41 and the optical axis turning unit 4 in the projection optical system PL of this example.
3 folds back almost in the + Z direction. The image forming light flux forms an intermediate image of substantially the same size as the pattern in the illumination area 15 in the process of being successively turned back in the substantially + Y direction and the −Z direction by the optical axis deflecting unit 46, and then the second objective unit A reduced image of the illumination area 15 is formed in the exposure area 16 on the wafer W via 52. With this configuration, in the projection optical system PL of this example, all the lenses L2 to L4, L11
L21, L31, L32, L41 to L52 can be made axially symmetric, and almost all of the lenses are formed of quartz, and only three or four of the lenses are formed of fluorite. Achromatization can be performed with high accuracy within a range of about 100 pm, which is the bandwidth of the broadened illumination light IL.

The projection optical system PL of this embodiment is optically composed of the same-magnification optical system including the first objective section 41 and the optical axis turning section 43, the optical axis deflecting section 46, and the second optical section. It can be divided into three types: a reduced projection system composed of the objective unit 52,
As the mechanical structure, the small mirror 48 is
And the lens L11 of the optical axis turning portion 43. Therefore, if the lens L4, the small mirror 48, and the lens L11 are incorporated in the same lens barrel,
It is necessary to incorporate the small mirror 48 and the beam splitter 50 in the optical axis deflecting unit 46 into separate lens barrels for adjustment. However, if the small mirror 48 and the beam splitter 50 are incorporated in different lens barrels, there is a possibility that the orthogonality of the reflection surfaces of the two members may fluctuate. If the orthogonality between the two reflecting surfaces fluctuates, the imaging performance is degraded. In this embodiment, the same-magnification imaging system is connected to the first objective unit 41 via the lens barrel 47 of the optical axis deflecting unit 46. The small mirror 48 and the beam splitter 50 are fixed to the inside of the lens barrel 47.

When assembling the projection optical system PL, the first objective section 41, the optical axis turning section 43, the optical axis deflecting section 46, and the second objective section 52 are separately assembled and adjusted in advance. Thereafter, the lens barrel 44 of the optical axis turning part 43 and the lower part of the lens barrel 53 of the second objective part 52 are inserted into the through-holes of the upper plate of the column 25, and the flange 44a of the lens barrel 44 and the lens barrel 5
A washer is sandwiched between the third flange 53a and the upper plate of the column 25, and the flanges 44a and 53a are temporarily fixed to the upper plate with screws. Next, the lens barrel 47 of the optical axis deflecting unit 46 is placed on the upper ends of the lens barrels 44 and 53, and a washer is sandwiched between the flange 47a of the lens barrel 47 and the flange 53b of the upper end of the lens barrel 53. Temporarily fix it on the flange 53b with a screw.

Then, a laser beam for adjustment is applied to the inside of the lens barrel 44 from above the lens L 11 in the lens barrel 44, and the laser beam is applied to the lens L 5 at the lowermost end of the lens barrel 53.
A position (a position on the surface corresponding to the surface of the wafer W) that is ejected from the wafer 2 and is monitored, and the flanges 44a, 53a, and 4 are set so that the monitored position becomes a target position.
Adjusting the thickness of the washer at the bottom of 7a, the lens barrels 42, 53, 4
7 and so on. Then, with the position of the laser beam reaching the target position, the flanges 44a, 53a,
47a by screwing, the optical axis turning portion 4
3. The second objective section 52 and the optical axis deflecting section 46 are fixed. Finally, the lens barrel 42 of the first objective unit 41 is moved above the end of the lens barrel 47 in the −Y direction, and between the flange (not shown) of the lens barrel 42 and the corresponding flange (not shown) of the lens barrel 47. The lens barrel 42 is placed on the lens barrel 47 with a washer therebetween. And
The laser beam for adjustment is again irradiated from above the lens L1 of the lens barrel 42 to adjust the optical axis.
By screwing the lens barrel 42 upward, the incorporation of the projection optical system PL into the projection exposure apparatus ends.

Further, in the present embodiment, taking into account the stability of the imaging characteristics against vibration and the balance of the projection optical system PL, the entire projection optical system PL is located outside the optical path of the imaging light beam within the projection optical system PL. The position of the center of gravity 54 is set. That is, in FIG. 3, the center of gravity 54 of the projection optical system PL is located near the middle between the optical axis turning part 43 and the second objective part 52, and the flange 44 a of the lens barrel 44 and the flange 5 of the lens barrel 53.
It is set at a position slightly lower than 3a (inside the upper plate of the column 25). Thus, the center of gravity 5 of the projection optical system PL is
By further setting 4 near the flanges 44a and 53a, the projection optical system PL has a structure that is more resistant to vibration and has high rigidity.

As described above, an intermediate image plane conjugate with the pattern surface of the reticle R exists inside the optical axis deflecting unit 46 of the projection optical system PL of this embodiment and near the beam splitter 50. A correction optical system 49 is arranged near the intermediate image plane. The reticle R projected on the wafer W by, for example, finely moving a lens group as the correction optical system 49 in the direction of the optical axis AX2 or adjusting the inclination angle of the lens group with respect to a plane perpendicular to the optical axis AX2. The imaging magnification of the reduced image and the imaging characteristics such as distortion can be corrected. On the other hand, conventionally, such an imaging characteristic correcting mechanism is provided almost immediately below the reticle R. According to this example, there is no imaging characteristic correction mechanism immediately below the reticle R, and there is no restriction on the mechanism. Therefore, there is an advantage that the rigidity of the reticle support 18 in FIG. 2 can be increased in design. Further, if an optical system capable of fine movement similar to the correction optical system 49 is provided in the optical axis turning section 43 or the second objective section 52, correction of aberration (astigmatism, coma, etc.) of the projected image and image plane The curvature can be corrected. Further, it is also possible to correct a higher-order magnification error by using these combinations.

Next, referring to FIG. 4, reticle R of FIG.
The positional relationship between the upper illumination area 15 and the exposure area 16 on the wafer W will be described.

FIG. 4A shows the illumination area 15 on the reticle R in FIG. 3. In FIG. 4A, the circular effective illumination field of the first objective section 41 of the projection optical system PL in FIG. 41
A rectangular illumination region 15 long in the X direction is set at a position slightly deviated from the optical axis AX1 in the −Y direction within “a”. The short side direction (Y direction) of the illumination area 15 is the scanning direction of the reticle R. In FIG. 3, the first objective unit 41
In the same-magnification optical system including the optical axis turning section 43, the image forming light flux passing through the illumination area 15 on the reticle R is turned by the concave mirror 45 and guided to the small mirror 48, so that the illumination area 15 is in the optical axis AX1. It is necessary to be eccentric with respect to.

On the other hand, FIG. 4B shows an exposure area 16 (an area conjugate with the illumination area 15) on the wafer W in FIG. 3, and in FIG. 4B, the projection optical system PL in FIG. 2 circular effective exposure field 52 of the objective section 52 (reduction projection system)
A rectangular exposure area 16 long in the X direction is set at a position slightly deviated in the + Y direction with respect to the optical axis AX3 within a.

On the other hand, FIG. 4C shows the state shown in FIG.
Similarly, the rectangular illumination area 15 is set at a position slightly deviated in the −Y direction with respect to the optical axis AX1 in the circular effective illumination visual field 41a. Also, FIG.
The effective exposure field 52aA of the second objective section obtained by deforming the second objective section 52 of FIG.
A rectangular exposure region 16A (a region conjugate with the illumination region 15 in FIG. 4C) that is long in the X direction is set around the optical axis AX3A of aA. That is, as shown in FIG. 4D, the second objective section 52, which is the final stage of the projection optical system PL,
By changing the configuration of the (reduction projection system), the exposure area 16A on the wafer W can be set to an area centered on the optical axis of the effective exposure field 52aA. FIG. 4 (b) and FIG.
4D is selected depending on the easiness of design for removing the aberration of the projection optical system PL. FIG. 4B is easy to design, and FIG. 4D is the second objective unit. (Reduced projection system)
There is an advantage that the lens diameter can be slightly reduced.

In this embodiment, as shown in FIG. 1, the illumination optical system 110 configured as described above, the reticle stage 18 (see FIG. 2), the projection optical system PL, and the wafer W are held. The base plate 23 of the wafer stage 22 (see FIG. 2) is housed inside the housing 102, and the inside has a sealed structure.

An oxygen concentration sensor 118 for detecting the oxygen concentration in the housing 102 is mounted inside the housing 102 so that the oxygen concentration in the housing 102 can be detected. The oxygen concentration signal inside the housing 102 detected by the sensor 118 is input to the main controller 7.

In the present embodiment, the housing 102 includes the housing 1
An inert gas supply line 121 for supplying helium, nitrogen gas, or the like as an inert gas is connected so that the inside of 02 has an atmosphere that reduces the rate of ozone generation due to the passage of illumination light. This supply line 121
Is connected to a nitrogen gas tank 120 as a gas supply device for supplying an inert gas. Also, supply line 1
In the middle of 21, a control valve 12 constituted by an electromagnetic valve or the like is provided.
2 is mounted, and the supply amount of an inert gas such as a nitrogen gas supplied from the tank 120 to the inside of the housing 102 can be controlled. The control of the control valve 122 is performed by the sensor 1
Based on 18, the control is performed by a control signal from the main control device 7 so that the concentration of oxygen gas inside the housing 102 does not increase beyond a certain level.

In exposure apparatus 100 according to this embodiment, illumination optical system 110, projection optical system PL, reticle stage 18 for reticle R (see FIG. 2), and wafer stage 22 for wafer W (see FIG. 2). Since the main body of the apparatus including the surface plate 23 is covered with the housing 102, and the inside of the housing 102 has a sealed structure in which an inert gas atmosphere such as nitrogen gas reduces the rate of generation of ozone due to the passage of illumination light, It has the following effects.

That is, in the exposure apparatus 100, the entire apparatus main body is covered with the housing 102 and has an inert gas atmosphere, as compared with the conventional exposure apparatus in which only the optical path portion has a closed structure. A certain reticle stage 1
Also at the portion 8 and the wafer stage 22, exposure of the exposure illumination light to air can be prevented, and generation of ozone due to passage of the exposure illumination light can be greatly reduced.

The reticle stage 1 which is a movable part
Since the exposure of the illumination light to the air can be prevented also at the portion 8 and the wafer stage 22, it is possible to prevent the light intensity from being reduced due to the influence of absorption by the air. In particular, vacuum ultraviolet light, especially light with a wavelength shorter than 250 nm,
For example, KrF excimer laser (wavelength 248 nm), A
Even when short-wavelength light such as rF excimer laser (wavelength 193 nm), F ₂ laser (wavelength 157 nm), or higher harmonics such as YAG laser is used as exposure light, the light intensity is affected by absorption by oxygen and the like. Problems such as lowering and generating harmful ozone gas can be effectively solved.

In the exposure apparatus 100 of the present embodiment,
Since the projection optical system PL and the illumination optical system 110 are not hermetically sealed, the projection optical system PL and the illumination optical system 11 are not closed.
In the design of 0, it is not necessary to design and manufacture in consideration of confidentiality, and these can be easily manufactured.

Further, unlike the technique disclosed in Japanese Patent Application Laid-Open No. Hei 6-260385, the exposure apparatus 100 of the present embodiment does not have a configuration in which a gas other than air, such as nitrogen gas, is blown to the vicinity of the wafer W. Does not leak, so that a decrease in the oxygen partial pressure in the working environment can be effectively prevented. Further, in the exposure apparatus 100 of the present embodiment, a sensor 118 for detecting the oxygen concentration in the housing 102 is mounted, and a nitrogen gas is supplied from the inert gas tank 120 into the housing 102 according to the output of the sensor 118. And the like. Therefore, in the exposure apparatus 100, when the oxygen concentration inside the housing 102 is increased to a predetermined value or more for some reason, an inert gas is supplied into the housing according to the output of the sensor 118. Problems such as a decrease in light intensity and generation of harmful ozone gas due to the influence of absorption by oxygen and the like can be effectively solved. In addition,
The inert gas supplied from the tank 120 is not limited to nitrogen gas, but may be helium gas or the like. Especially 150 ~
In the case of using exposure illumination light having an oscillation spectrum in a wavelength region of 200 nm, it is preferable to use helium, whose characteristics are less likely to change as compared with nitrogen or the like with respect to a change in atmospheric pressure or the like.

Second Embodiment In this embodiment, instead of not using the inert gas tank 120 shown in FIG.
And connected by a vacuum pump 125 as a vacuum device.
The inside of the housing 102 can be made into a vacuum state of 1 × 10 ⁻⁴ Torr or less. A control valve 124 composed of an electromagnetic valve or the like is mounted in the middle of the evacuation line 123 so that opening and closing of the vacuum line 123 can be controlled. The control valve 124 and the vacuum pump 125 are controlled by the main controller 7, so that the inside of the housing 102 can be brought into a vacuum state of 1 × 10 ⁻⁴ Torr or less at least during exposure.

In the exposure apparatus 100 according to the present embodiment, by setting the inside of the housing 102 to a vacuum state of 1 × 10 ⁻⁴ Torr or less, the intensity of the illumination light for exposure decreases due to the influence of absorption by oxygen and the like. And the problem of generating harmful ozone gas can be effectively solved.

In the present embodiment, the inside of the housing 102 is evacuated. However, heat generated by light absorption of a portion of the optical element such as a lens to which the illumination light for exposure is irradiated is generated by air or the like as in the related art. Since it is not transmitted by the ambient gas, a temperature controller for cooling the optical element is required. Therefore, in the present embodiment, the illumination optical system 1 shown in FIG.
10 and / or cool at least a part of the optical elements of the projection optical system PL. FIG. 5 shows an example of a temperature control device for cooling.

In the example shown in FIG. 5, a cooling passage 136 for circulating a lens cooling liquid 134 is formed in a part of a lens holding mechanism 132 for holding a lens L as an optical element. The lens L can be cooled by flowing the lens cooling liquid 134 to the lens L. The lens cooling liquid 134 is not particularly limited, but pure water whose temperature is adjusted is used.

In the example shown in FIG. 6, a part of a lens holding mechanism 132 for holding a lens L as an optical element includes
Injection nozzle 13 that blows a rare gas 140 (for example, an inert gas such as nitrogen gas) toward the surface of lens L
8 is attached. By blowing the rare gas 140 onto the surface of the lens L, the lens L can be cooled. However, spraying from the injection nozzle 138 is preferably performed at the time of non-exposure.
It is necessary to adjust the degree of vacuum so that a vacuum state of × 10 ⁻⁴ Torr or less is obtained.

In this embodiment, the coolant passage 1 shown in FIG.
The lens L as an optical element is cooled by using a temperature adjusting device constituted by the nozzle 36 and / or the injection nozzle 138 shown in FIG. Changes can be suppressed.

The other configuration of the exposure apparatus 100 of the present embodiment is the same as that of the exposure apparatus 100 of the first embodiment, and has the same operation.

It is important to keep the optical element at a constant temperature even if the inside of the housing 102 is not evacuated as in the present embodiment, and the optical element such as a lens is cooled using a temperature adjusting device. By doing so, it is possible to suppress a change in optical conditions due to heat of an optical element such as a lens.

For example, in the exposure apparatus 100 according to the above-described first embodiment, the inside of the housing 102 is filled with an inert gas. In such a case, the injection nozzle 138 shown in FIG. Preferably, the same temperature-controlled gas as the inert gas in the atmosphere is blown onto the lens L. Cooling of the lens L becomes possible by spraying from the injection nozzle 137.

Third Embodiment As shown in FIG. 7, the projection exposure apparatus 10 according to the third embodiment
In 0a, the illumination optical system 110 and the projection optical system PL are arranged in casings 160 and 162, respectively. Each of the casings 160 and 162 has a closed structure, similarly to the housing 102 shown in FIG.

First casings 160 and 162 are connected to first gas supply lines 153 and 163, respectively. A first gas tank 120a is connected to each of the supply lines 153 and 163, and the control valves 154, 16
The opening and closing of 4 allows the first gas to be supplied from the first gas tank 120a into each of the casings 160 and 162. Opening / closing control of the control valves 154 and 164 is performed by the main controller 7 shown in FIG.

In this embodiment, a plurality of second gas injection nozzles 150 as a gas supply mechanism are mounted on the wafer stage 22a for holding the wafer W. The second gas injection nozzle 150 is connected to a second gas supply line 151, and this supply line 151 is connected to a second gas tank 120b via a control valve 152. The opening and closing control of the control valve 152 is performed by the main controller 7 shown in FIG. By controlling the control valve 152, the second gas injection nozzle 150 blows out the second gas from the second gas tank 120b between the projection optical system PL and the wafer W during exposure of the wafer W. ing.

A second gas supply line 155 is also connected to the second gas tank 120b, and the second gas injection nozzle 15 mounted on a reticle stage not shown in FIG.
From 7, the second gas is blown into the space between the illumination optical system 110 and the projection optical system PL. The control of blowing the second gas from the second gas injection nozzle 157 is performed by a control valve 156 mounted on the supply line 155. Control valve 156 is controlled by main controller 7 shown in FIG.

The amount of the second gas blown from the nozzles 150 and 157 is not particularly limited, but is an amount that can sufficiently replace the air present in the blown space with the second gas. During the exposure, the illumination light for exposure also passes through the space from which the second gas has been blown out, thereby preventing ozone generation and light intensity reduction at that portion.

In the present embodiment, the first gas supplied into the casings 160 and 162 through the supply lines 153 and 163 is helium gas, and is blown out from the nozzles 150 and 157 through the supply lines 151 and 155. The second gas is nitrogen gas. As the first gas, a relatively expensive inert gas such as helium gas which does not reduce the light intensity and has an excellent effect of not generating harmful ozone gas is used because it is sealed in the casings 160 and 162. This is because it is economical and safe to use relatively inexpensive nitrogen contained in air as the second gas released to the environment. In particular, the use of helium is premised on 150 to 20
In an exposure apparatus that uses illumination light for exposure having an oscillation spectrum in a wavelength range of 0 nm, a housing purged with helium has a light transmitting system and an illumination optical system 110 arranged between the light source 2 and the illumination optical system 110. , And the projection optical system PL, and an increase in running cost and the like can be minimized.

In the exposure apparatus 100a according to the present embodiment,
The illumination optical system 110 and the projection optical system PL are respectively disposed in casings 162 and 160 filled with the first gas,
During the exposure of the wafer W, the second gas flows in the space between the projection optical system PL and the wafer W and in the space between the illumination optical system 110 and the projection optical system PL. For this reason, in the present embodiment, the minimum necessary portion is covered with the casings 160 and 162, and the first
Since the gas has a specific internal atmosphere, exposure of the illumination light for exposure to air can be prevented inside the casings 160 and 162, and generation of ozone due to passage of the illumination light for exposure can be greatly reduced.

The wafer stage 22 which is a movable part
a and the reticle stage (not shown in FIG. 7), during the exposure of the wafer W, by flowing the second gas to these portions, the exposure of the illumination light to air can be reduced as much as possible, and the generation of ozone can be reduced. In addition to suppressing the light intensity, it is possible to prevent the light intensity from decreasing. In particular, vacuum ultraviolet light, particularly short wavelength light than 250 nm, for example a KrF excimer laser (wavelength 248 nm), ArF excimer laser (wavelength 193 nm), F ₂ laser (wavelength 157 nm),
Alternatively, even when short-wavelength light such as a harmonic wave of a YAG laser or the like is used as exposure light, problems such as reduction in light intensity and generation of harmful ozone gas due to the absorption of oxygen can be effectively achieved. Can be eliminated.

Further, the exposure apparatus 100a according to this embodiment
In comparison with an exposure apparatus in which the entire body of the apparatus is covered by a housing and has a hermetically sealed structure, the minimum necessary parts are
Since the exposure apparatus is covered with 162, there is an advantage that the entire exposure apparatus does not have a large structure. Further, it is not necessary to adjust the atmosphere inside the housing every time the wafer W or the reticle R is exchanged, so that the throughput of the exposure operation is improved.

The present invention is not limited to the above-described embodiment, but can be variously modified within the scope of the present invention.

For example, in the embodiment shown in FIG. 7, the illumination optical system 110 and the projection optical system PL are provided in separate casings 1.
60 and 162, and the nozzle 157 is disposed between them. In the present invention, the nozzle 157 is not provided.
The casing 160 and the casing 162 may be connected. In that case, the illumination optical system 11 on which a reticle stage (not shown in FIG. 7) for holding the reticle R is arranged.
The space between 0 and the projection optical system PL is also accommodated in the casing. The reticle stage is also a movable part,
Since it is smaller than the surface plate 23 of the wafer stage (see FIGS. 1 and 2), even if the reticle stage is arranged in a casing filled with the first gas, the whole apparatus does not become so large.

In the above-described embodiment, an exposure apparatus of a so-called step-and-scan method has been described as an example of an exposure apparatus. However, the present invention is not limited to this type of exposure apparatus. The present invention can also be applied to a repeat type exposure apparatus and another type of exposure apparatus.

Further, in the above-described embodiment, the wafer on which the resist is formed is illustrated as an example of the photosensitive substrate to be exposed, but another substrate may be used.

[0115]

As described above, according to the present invention, it is possible to effectively suppress the decrease in the intensity of exposure light and the generation of ozone, particularly in an exposure apparatus that performs exposure using light having a short wavelength. it can.

[Brief description of the drawings]

FIG. 1 is an overall configuration diagram of an exposure apparatus according to an embodiment of the present invention.

FIG. 2 is a schematic view of the exposure apparatus main body shown in FIG.

FIG. 3 is a schematic sectional view of the projection optical system shown in FIG.

FIGS. 4A to 4D are explanatory diagrams showing a relationship between an illumination area and an exposure area of a projection optical system and a modification of the exposure area.

FIG. 5 is a schematic sectional view showing a lens holding mechanism used in an exposure apparatus according to another embodiment of the present invention.

FIG. 6 is a schematic sectional view showing a lens holding mechanism used in an exposure apparatus according to another embodiment of the present invention.

FIG. 7 is a main part configuration diagram of an exposure apparatus according to still another embodiment of the present invention.

[Explanation of symbols]

 R: Reticle (mask) W: Wafer (photosensitive substrate) PL: Projection lens system 2: Light source 18: Reticle stage (first holding member) 22: Wafer stage (second holding member) 23: Surface plate 100, 100a Exposure apparatus 102 Housing 110 Illumination optical system 120 Inert gas tank 120a First gas tank 120b Second gas tank 121 Inert gas supply line 123 Evacuation line 125 Vacuum pump 134 Lens cooling liquid 136 Cooling passage 138 Injection nozzle 150, 157 Second gas injection nozzle 151, 155 Second gas supply line 153, 163 First gas supply line 160, 162 Casing

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁶ Identification code FI H01L 21/30 516E

Claims (14)

[Claims] A light source that emits illumination light for exposure; an illumination optical system that irradiates the illumination light onto a mask; a first holding member that holds the mask; An exposure apparatus comprising: a projection optical system that projects onto a substrate; and a second holding member that holds the photosensitive substrate, wherein at least a part of the illumination optical system, the projection optical system, and the first An exposure apparatus, wherein the exposure apparatus has a sealed structure in which an apparatus main body including a first holding member and a second holding member is covered with a housing, and the inside of the housing has an atmosphere that reduces the rate of generation of ozone due to the passage of the illumination light. . 2. The illumination device according to claim 1, wherein the illumination light has an oscillation spectrum in a range of 150 to 250 nm, and further includes a vacuum device for evacuating the inside of the housing to 1 × 10 ⁻⁴ Torr or less. Exposure equipment. 3. The apparatus according to claim 1, further comprising: a sensor for detecting an oxygen concentration in the housing, and a gas supply device for supplying an inert gas into the housing in accordance with an output of the sensor. 2. The exposure apparatus according to 1. 4. The exposure apparatus according to claim 3, wherein the illumination light has an oscillation spectrum at 150 to 200 nm, and the inert gas is helium. 5. The exposure apparatus according to claim 1, further comprising a temperature adjusting device for cooling at least one optical element of the illumination optical system and the projection optical system. 6. The temperature control device according to claim 1, wherein
6. The exposure apparatus according to claim 5, wherein a temperature-controlled fluid is supplied into a holding device that holds the two optical elements. 7. The housing is filled with an inert gas, and the temperature control device has an injection device that blows the same temperature-controlled gas as the inert gas onto the at least one optical element. The exposure apparatus according to claim 5, wherein: 8. A light source for emitting illumination light for exposure, an illumination optical system for irradiating the mask with the illumination light, and a projection optical system for projecting illumination light emitted from the mask onto a photosensitive substrate. In the exposure apparatus, the illumination optical system and the projection optical system are respectively disposed in a casing filled with a first gas, and during the exposure of the photosensitive substrate, between the projection optical system and the photosensitive substrate. An exposure apparatus, further comprising a gas supply mechanism for flowing a second gas into a space. 9. The exposure apparatus according to claim 8, wherein the first gas is an inert gas other than nitrogen, and the second gas is a nitrogen gas. 10. The exposure apparatus according to claim 8, wherein the illumination light has an oscillation spectrum at 150 to 200 nm, the first gas is helium, and the second gas is nitrogen. . 11. The method according to claim 8, wherein the second gas is caused to flow in a space between the illumination optical system on which a mask stage holding the mask is arranged and the projection optical system.
The exposure apparatus according to any one of claims 10 to 13. 12. The exposure apparatus according to claim 8, wherein a mask stage for holding the mask is disposed in the casing filled with the first gas. 13. A drive device for synchronously moving the mask and the photosensitive substrate at a speed ratio according to a magnification of the projection optical system in order to transfer the pattern of the mask onto the photosensitive substrate. 2. The method according to claim 1, wherein
3. The exposure apparatus according to any one of 2. 14. The exposure apparatus according to claim 1, wherein the illumination light is an F ₂ laser.