JP2002033258A - Aligner, mask apparatus, pattern protective apparatus, and method of manufacturing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To well and properly maintain the transmissivity of exposing light. SOLUTION: An aligner is provided with a gas-supplying system, which supplies a prescribed low-absorptivity gas, such as the nitrogen, rare gas, etc., to a protective space PS, surrounded by the patterned surface of a reticle R carrying a pellicle 75 fitted to the patterned surface via a frame 76 and the pellicle 75 while the reticle R is held by a reticle holder 14. When the low- absorptivity gas is supplied, the gas existing in the protective space PS is replaced by the supplies gas. Consequently, the gas replacement in the space PS, which has not been considered conventionally can be performed. Therefore, the transmittance of the exposed light EL can be maintained well and stably, well and stable, because the gas replacement in the spaces on all optical paths of the exposing light EL including the protective space SP can be realized easily.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to an exposure apparatus, a mask apparatus, a pattern protection apparatus, and a device manufacturing method, and more particularly, to an electronic device such as a semiconductor element (integrated circuit) and a liquid crystal display element (liquid crystal display). The present invention relates to an exposure apparatus used in a lithography step, a mask apparatus and a pattern protection apparatus suitable for being applied to the exposure apparatus, and a device manufacturing method using the exposure apparatus.

[0002]

2. Description of the Related Art Conventionally, various exposure apparatuses have been used in a lithography process in the manufacture of semiconductor devices, liquid crystal display devices, and the like. In recent years, the pattern to be formed
A step-and-repeat type reduction projection exposure apparatus (which reduces and transfers a pattern of a mask (also called a reticle) formed in proportion to about 5 times onto a substrate to be exposed such as a wafer via a projection optical system ( So-called stepper)
Further, a projection exposure apparatus such as a step-and-scan type scanning projection exposure apparatus (a so-called scanning stepper) obtained by improving the stepper is mainly used.

In these projection exposure apparatuses, the exposure wavelength has been shifted to shorter wavelengths in order to realize high resolution in response to miniaturization of integrated circuits. Currently, its wavelength is K
The mainstream is 248 nm of rF excimer laser, but 193 nm of shorter wavelength ArF excimer laser is also entering the stage of practical use. In an exposure apparatus having such an exposure wavelength, phenomena such as the exposure light being absorbed by substances (mainly organic substances) in the air and the organic substances activated by the exposure light adhering to a lens or the like and causing deterioration in transmittance are caused. Occur. Therefore, it is said that it is effective to fill the space in the optical path with air or other gas from which the organic substances have been removed in order to remove organic substances from the optical path.

Further, when contaminants such as dust and chemical contaminants adhere to a pattern on a mask or a reticle (hereinafter collectively referred to as a “reticle”), the transmittance of the portion is reduced and the contaminants are removed. When transferred onto a wafer, pattern transfer is erroneous. Therefore, it is common practice to cover the pattern forming surface (pattern surface) of the reticle with a thin film called a pellicle to prevent the pattern surface from being contaminated by dust or the like. The pellicle is placed at a position about 6.3 mm away from the reticle pattern surface by a metal frame called a pellicle frame.

[0005]

By the way, it is certain that the exposure wavelength will be further shortened in the future.
A projection exposure apparatus using a light source that emits light belonging to the vacuum ultraviolet region having a shorter wavelength than the F excimer laser, for example, an F ₂ laser with an output wavelength of 157 nm, or an Ar ₂ laser with an output wavelength of 126 nm has been developed or proposed.

However, these luminous fluxes in a wavelength range called vacuum ultraviolet have poor transmittance of optical glass, and usable lenses and reticle materials are fluoride crystals such as fluorite, magnesium fluoride, and lithium fluoride. Is limited to
Further, these luminous fluxes are extremely greatly absorbed by, for example, most of oxygen, water vapor, and general organic substances (hereinafter, referred to as “absorptive gas”). Therefore, in an exposure apparatus that uses a light beam in the vacuum ultraviolet region as exposure light, in order to reduce the concentration of the absorbing gas in the space on the optical path through which the exposure light passes to a concentration of several ppm or less, the gas in the space on the optical path is reduced. It is necessary to replace with a rare gas such as nitrogen or helium (hereinafter referred to as a “low-absorbing gas”) that absorbs less exposure light.

[0007] Replacing the air in the space on the optical path of the exposure light with air from which ozone has been removed or dry air,
If a similar technique is used, it is possible to easily replace almost all the gas in the space on the optical path with the low-absorbing gas.

On the other hand, the pellicle is mounted on the reticle in order to prevent dust from adhering to the pattern surface of the reticle. Therefore, a space surrounded by the reticle pattern surface, the pellicle and the pellicle frame (hereinafter referred to as "the pellicle" as appropriate) The protection space is sealed with high airtightness to prevent dust from entering from outside, so even if the air on the optical path of the exposure light is replaced, the protection space has low absorption. Not replaced by neutral gas. For this reason, for example, when a pellicle made of an organic substance is used, sublimation of the organic gas from the pellicle material and desorption of the organic gas due to a chemical reaction caused by exposure to exposure light form an organic gas in the protection space,
It is accumulated and reduces the transmittance of the exposure light.

In order to further increase the transmittance of the exposure light,
Since the pellicle is formed of an extremely thin thin film, the permeability of ordinary gas molecules is high, and the above-mentioned absorbent gas such as oxygen or water vapor easily penetrates the pellicle and enters and accumulates in the protection space. When vacuum ultraviolet light is used as the exposure light, its transmittance may be reduced.

As described above, when the transmittance of the exposure light decreases, not only the exposure power and the throughput associated therewith decrease, but also the line width of the transfer pattern changes due to the fluctuation of the exposure power. This may cause a semiconductor device failure.

The present invention has been made under such circumstances, and a first object of the present invention is to provide an exposure apparatus capable of maintaining a good and stable exposure light transmittance.

A second object of the present invention is to provide a mask device capable of improving the gas replacement efficiency and a pattern protection device suitably applicable to the mask device.

Still another object of the present invention is to provide a device manufacturing method capable of improving the productivity of a highly integrated device.

[0014]

According to the first aspect of the present invention, a mask (R) is irradiated with an energy beam (EL),
An exposure apparatus for transferring a pattern formed on the mask onto a substrate (W), holding the mask having a pattern protection material (75) mounted on a pattern surface (54a) thereof via a frame (76). Mask holding member (14)
A predetermined gas is injected into a space (PS) surrounded by the pattern surface, the frame, and the pattern protection material while the mask having the pattern protection material mounted on the mask holding member is held. Gas supply system (20,
51A, 55, 66).

Here, the predetermined gas is a gas having little influence on exposure accuracy, exposure power, and the like, such as a gas having low absorption of an energy beam (a low-absorbing gas) and a gas which does not cause fogging on a pattern surface. Means That is, as the predetermined gas, for example, when light belonging to the vacuum ultraviolet region is used for the energy beam, a rare gas such as nitrogen or helium can be used as the gas having low absorption of the energy beam. When light belonging to the near-ultraviolet region is used for the beam, air or the like in which the concentration of organic substances is low can be used. Also,
As a gas that does not cause clouding or the like on the pattern surface, air from which oxygen, water vapor, and the like have been removed can be used.

According to this, the mask holding member is surrounded by the pattern surface of the mask, the frame and the pattern protection material while the mask having the pattern protection material mounted on the pattern surface via the frame is held by the mask holding member. A predetermined gas is supplied by a gas supply system into the space (hereinafter, appropriately referred to as “protected space”). By the supply of the gas, the gas in the protection space is replaced with a predetermined gas, thereby making it possible to perform the gas replacement in the protection space which has not been considered in the related art. Therefore, it is possible to easily realize gas replacement in the space on the entire optical path of the energy beam including the inside of the protection space, and it is possible to maintain the exposure light transmittance satisfactorily and stably. And the throughput can be improved, and the line width of the pattern transferred onto the substrate can be maintained uniform.

In this case, the supply of the gas may be performed through a hole provided in any place as long as it is a ventilation hole for communicating the inside and the outside of the protection space. It may be performed through a formed hole, a concave groove or a notch formed in any member at a contact portion between the mask and the frame, or as in the invention according to claim 2, The supply of the gas is performed by a supply vent (7) formed in the frame.
7A).

In the exposure apparatus according to each of the first and second aspects of the present invention, as in the third aspect of the present invention, the gas exhaust system (51B, 51B,
6, 78). In such a case, since the gas in the protection space is positively exhausted to the outside by the gas exhaust system, the gas in the protection space is replaced with a predetermined gas, and the gas replacement efficiency can be improved. Further, for example, by exhausting the gas exhausted from the protection space by the gas exhaust system to the outside of the optical path of the energy beam, the other optical paths are not contaminated by the gas flowing out of the protection space, and the exposure power is reduced. Higher stability can be maintained.

In this case, the exhaust of the gas may be performed through a hole provided in any place as long as it is a ventilation hole for communicating the inside and the outside of the protection space, and may be provided in the pattern protection material. The gas exhaust may be performed through a hole provided or a groove or notch formed in any member at a contact portion between the mask and the frame, as in the invention according to claim 4. May be performed through an exhaust vent (77B) formed in the frame.

In the exposure apparatus according to each of the second and fourth aspects of the present invention, as in the fifth aspect of the present invention, the frame has a polygonal shape in a mounting surface to the pattern surface. The ventilation holes (77A to 77D) may be provided at corners of the polygon. In such a case, since the ventilation holes are provided at the corners of the polygonal frame, the gas flow is actively formed at the corners where gas convection is small and gas accumulation is likely to occur. The pool is eliminated, and efficient gas replacement can be realized.

According to a sixth aspect of the present invention, there is provided an exposure apparatus for irradiating a mask (R) with an energy beam (EL) and transferring a pattern formed on the mask onto a substrate (W). A transport system (120) for transporting the mask with the pattern protection material (75) mounted on the surface thereof via a frame (76) toward a mask holding member (14);
In a transport path of the mask by the transport system, a predetermined space is provided in a space (PS) surrounded by the pattern surface, the frame, and the pattern protective material via a supply hole provided at a corner portion of the frame. A first gas supply system (20 ′, 51A′83, 152A) for supplying gas.

According to this, the mask having the pattern protection material attached to the pattern surface via the frame is transported toward the mask holding member by the transport system, and the frame is transported along the transport path of the mask by the transport system. A predetermined gas is supplied into the protection space by the first gas supply system through a supply hole provided in the corner portion. For this reason, it is possible to eliminate a gas that causes a decrease in the transmittance of the energy beam from the protection space (suppress the invasion of the absorbing gas into the protection space) during the transfer of the mask. Further, in this case, the gas is supplied through a supply hole provided at a corner portion of the frame where gas accumulation is likely to occur, so that the inside of the protection space can be efficiently replaced with a predetermined gas. As a result, it is possible to easily realize gas replacement of the space on the entire optical path of the energy beam including the protection space, and to maintain the transmittance of the energy beam satisfactorily and stably.

In this case, after the mask is loaded onto the mask holding member by the transport system, the predetermined gas enters the space via the supply hole. May be further provided with a second gas supply system (20, 51A, 55, 66) which constantly supplies the gas. In such a case, after the mask is loaded on the mask holding member, a predetermined gas is constantly supplied into the protection space through the supply hole by the second gas supply system, so that the transmittance of the energy beam is increased. Can be maintained favorably and stably for a long period of time.

The mask device according to the present invention is characterized in that a mask substrate (54) having a circuit pattern formed on one surface; and a pattern surface (54a) of the mask substrate having the circuit pattern formed thereon. A frame having a polygonal shape attached thereto and having a shape of a polygonal attachment surface; and a pattern protection material mounted on a surface of the frame opposite to the pattern surface. Vent holes (77A to 77D) are provided.

According to this, the mask device is mounted on the mask substrate having the circuit pattern formed on one surface and the pattern surface of the mask substrate having the circuit pattern formed thereon, and the mounting surface has a polygonal shape. And a pattern protection material mounted on a surface opposite to the pattern surface of the frame, and a vent is provided in a corner portion of the frame. Therefore, since the inside of the protection space and the outside of the protection space communicate with each other through the ventilation holes provided at the corners of the frame, when performing gas replacement in the protection space, gas generation is suppressed or prevented by suppressing or preventing gas accumulation. The replacement efficiency can be improved.

In this case, the vent may be provided in at least two or more corners of the frame. In such a case, the gas replacement efficiency can be further improved.

In the mask device according to each of the eighth and ninth aspects of the present invention, as in the tenth aspect of the present invention,
The ventilation hole may be provided with a dustproof filter (98). In such a case, the dust filter can prevent dust (particles) or the like from entering the protection space via the ventilation hole.

According to an eleventh aspect of the present invention, there is provided a pattern protection device for protecting a circuit pattern by attaching to a mask substrate having a circuit pattern formed thereon, the pattern protection material having a predetermined thickness; A material is provided on one surface thereof, the other surface is a mounting surface for the mask substrate, the mounting surface has a polygonal shape, and a frame having a vent hole formed at a corner thereof.

According to this, the pattern protection device comprises a pattern protection material having a predetermined thickness, the pattern protection material being mounted on one surface thereof, and the other surface being a mounting surface for the mask substrate. Has a polygonal shape, and has a frame in which a vent hole is formed in a corner portion.
Therefore, by attaching this pattern protection device to the mask substrate, dust (particles) is prevented from adhering to the surface (pattern surface) of the mask substrate by the frame and the pattern protection material, and the through holes formed at the corners of the frame are prevented. The gas in the protection space can be efficiently replaced with the predetermined gas through the pores.

According to a twelfth aspect of the present invention, there is provided a device manufacturing method including a lithography step, wherein exposure is performed in the lithography step using the exposure apparatus according to any one of the first to seventh aspects.

According to this, since the exposure is performed in the lithography process using each of the exposure apparatuses according to claims 1 to 7, the productivity of a highly integrated device can be improved by improving the throughput and the exposure accuracy. Can be.

[0032]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to FIG.
This will be described with reference to FIG. FIG. 1 schematically shows the configuration of an exposure apparatus 100 according to one embodiment. The exposure apparatus 100 includes exposure illumination light (hereinafter, abbreviated as “exposure light”) EL belonging to a vacuum ultraviolet region as an energy beam.
Is irradiated on a reticle R as a mask, and the reticle R
Is a step-and-repeat reduction projection exposure apparatus that transfers a pattern formed on a wafer W as a substrate via a projection optical system PL, that is, a so-called stepper.

The exposure apparatus 100 includes a light source 1 and an illumination optical unit IOP.
, A reticle holder 14 as a mask holding member for holding the reticle R, and a projection optical system P for projecting the exposure light EL emitted from the reticle R onto the wafer W
L, a wafer stage WST for holding the wafer W, and the like.

The light source 1 here has a wavelength of about 1
A light source that emits light belonging to the vacuum ultraviolet region from 20 nm to about 190 nm, for example, a fluorine laser (F
₂ ), a krypton dimer laser (Kr ₂ laser) with an output wavelength of 146 nm, an argon dimer laser (Ar ₂ laser) with an output wavelength of 126 nm, and the like. Note that an ArF excimer laser having an output wavelength of 193 nm may be used as a light source.

The light source 1 includes a light transmitting optical system 13 partially including an optical system for adjusting an optical axis called a beam matching unit.
Is connected to one end of the illumination optical unit IOP.

The illumination optical unit includes an illumination system housing 2 and an optical integrator (homogenizer) such as a bending mirror 3, a fly-eye lens, or a rod-type integrator (internal reflection type integrator) arranged in a predetermined positional relationship inside the housing. 4) a beam splitter 5 having a large reflectance and a small transmittance, relay lenses 7 and 8,
An illumination optical system including a reticle blind BL as a field stop, a bending mirror 9, and the like is provided. Reticle blind BL is arranged on a plane conjugate with the pattern plane of reticle R. A light amount monitor 6 composed of a photoelectric conversion element is arranged on the transmitted light path of the beam splitter 5.

Here, the operation of the illumination optical system will be briefly described. The light beam (laser beam) LB in the vacuum ultraviolet region that has entered the illumination system housing 2 almost horizontally from the light source 1 via the light transmission optical system 13 is The optical path is bent 90 degrees by the bending mirror 3 and enters the optical integrator 4. The laser beam LB is converted by the optical integrator 4 into exposure light EL having a substantially uniform intensity distribution, and most (for example, about 97%) of the laser beam LB is reflected by the beam splitter 5 and passed through the relay lens 7 to the reticle. The blind BL is illuminated with uniform illuminance. Exposure light E transmitted through rectangular opening of reticle blind BL
L illuminates the rectangular illumination area defined by the opening of the reticle blind BL on the reticle R with substantially uniform illuminance via the relay lens 8, the bending mirror 9, and the light transmission window 12 described later.

On the other hand, the exposure light EL of the remaining portion (for example, about 3%) transmitted through the beam splitter 5
Is received and photoelectrically converted, and the photoelectric conversion signal is supplied to a control device (not shown). In the control device, the light source 1
With the start of light emission, the illuminance on the image plane (wafer W plane) is estimated by a predetermined calculation based on the output of the light amount monitor 6,
The integrated exposure amount to be given to each point on the wafer W is controlled based on the estimation result.

When light having a wavelength in the vacuum ultraviolet region is used as the exposure light, a gas (eg, oxygen, water vapor, hydrocarbon gas, etc.) having a strong absorption characteristic for light in this wavelength band from the optical path. Hereinafter, it is necessary to exclude the “absorbent gas” as appropriate. For this reason, in the present embodiment, a specific gas having a characteristic of little absorption of light in the vacuum ultraviolet region, for example, nitrogen and a rare gas such as helium, argon, neon, krypton, or the like, is provided inside the illumination system housing 2. (Hereinafter, appropriately referred to as “low-absorbent gas”), and the pressure thereof is set slightly higher than the atmospheric pressure, specifically, for example, about 1 to 10% higher than the atmospheric pressure. As a result, the concentration of the absorptive gas in the illumination system housing 2 is less than several ppm.

More specifically, as shown in FIG. 1, the illumination system housing 2 is provided with an air supply valve 10 at the end on the light source 1 side, and the other end farthest from the air supply valve 10. Is provided with an exhaust valve 11. As shown in FIG. 2, the air supply valve 10 includes an illumination system housing 2 and a gas supply device 50.
Is provided in the vicinity of an end on the illumination system housing 2 side of an air supply pipe connecting to one end of the first chamber. Also, the exhaust valve 11
Is provided near an end of the exhaust pipe connecting the illumination system housing 2 and the other end of the first chamber of the gas supply device 50 on the illumination system housing 2 side. The inside of the gas supply device 50 is divided into five rooms of a first room to a fifth room, and inside each room, a storage tank for low-absorbent gas, a pump, a gas purification device and the like (all not shown). ) Is built-in. A control device (not shown) controls the opening and closing of the air supply valve 10 and the exhaust valve 11 and the operation and stop of the pump incorporated in the first chamber of the gas supply device 50 as appropriate, so that the interior of the illumination system housing 2 can be controlled. Is filled with a low-absorbent gas, and the concentration of the absorptive gas in the illumination system housing 2 is several ppm or less. It should be noted that the low-absorbent gas may always flow in the illumination system housing 2. In addition, the gas supply device 5
The gas purifying device incorporated in the first chamber of the gas recirculation apparatus 0 regenerates the low-absorbing gas having a reduced purity after passing through the interior of the illumination system housing 2 to a predetermined purity again, such as a HEPA filter or an ULPA filter. Dust (particles)
Filter type including an air filter that removes air and a chemical filter that removes absorptive gas such as oxygen, water vapor, and hydrocarbon-based gas, or a cryopump using a gas liquefied by the cryopump. A type that separates the low-absorbent gas and impurities by utilizing the difference in the vaporization temperature of the substance contained in can be used. The storage tank inside each room of the gas supply device 50 is connected to an external low-absorbing gas supply source via a valve having a flow rate control function so that the insufficient low-absorbing gas is appropriately supplemented. Has become. In this case, the first gas supply device 50
Even if the low-absorbent gas is circulated for a long time by the circulation path including the interior of the illumination system housing 2 from the room, the action of the absorbent gas in the illumination system housing 2 is performed by the action of the gas purification device in the first room. The concentration can be kept below a few ppm.

In the present embodiment, the light paths inside the light source 1 and the light transmission optical system 13 are also replaced with a low-absorbing gas in the same manner as in the illumination system housing 2.

Returning to FIG. 1, the reticle holder 14
The reticle R is arranged in the reticle chamber 15 by suction and holding. The reticle chamber 15 is provided with a partition wall 18 that is joined without gaps to the illumination system housing 2 and the lens barrel of the projection optical system PL.
And the gas inside is isolated from the outside. The partition 18 of the reticle chamber 15 is made of stainless steel (SU
It is made of a material with low degassing such as S).

On the ceiling of the partition wall 18 of the reticle chamber 15,
A rectangular opening slightly smaller than the reticle R is formed.
The transmission window 12 is arranged so as to be separated from the internal space of the reticle chamber 15 in which the reticle R to be exposed is arranged. Since the transmission window 12 is disposed on the optical path of the exposure light EL applied to the reticle R from the illumination optical unit IOP, the transmission window 12 is made of a crystalline material such as fluorite having high transparency to vacuum ultraviolet light as exposure light. Is formed.

If the gas replacement in the illumination system housing 2 is performed once through a decompression operation, a pressure corresponding to the decompression is applied to the transmission window 12 during the decompression operation, and the fluorite may be damaged. is there. In such a case, a movable metal pressure-resistant lid is provided above the transmission window 12 in FIG. 1 to protect the transmission window 12 from a pressure difference.

The partition 18 of the reticle chamber 15 is provided with an air supply valve 16 and an exhaust valve 17 as shown in FIG. As shown in FIG. 2, the air supply valve 16 is provided near an end of the air supply pipe connecting the reticle chamber 15 and one end of the second chamber of the gas supply device 50 on the reticle chamber 15 side. The exhaust valve 17 is provided near an end of the exhaust pipe connecting the reticle chamber 15 and the other end of the second chamber of the gas supply device 50 on the reticle chamber 15 side. The control device (not shown) controls the opening and closing of the air supply valve 16 and the exhaust valve 17 and the operation and stop of the pump incorporated in the second chamber of the gas supply device 50 as appropriate, so that the reticle chamber 15 The low-absorbent gas is filled, and the concentration of the absorptive gas in the reticle chamber 15 is several ppm or less. It should be noted that the low-absorbent gas may always flow through the reticle chamber 15. Further, in the second chamber of the gas supply device 50, a gas purification device having the same function as the gas purification device built in the first chamber is built. Due to the operation of the gas purification device, even if the low-absorbent gas is circulated and used for a long time by the circulation path including the second chamber of the gas supply device 50 and the inside of the reticle chamber 15, the absorption in the reticle chamber 15 is prevented. The concentration of the gas can be maintained at a concentration of several ppm or less.

Returning to FIG. 1, outside the reticle chamber 15,
A reticle transfer chamber RI for storing a reticle loader as a transfer system described later is provided. The reticle transfer chamber RI is a partition 1 that forms the partition 125 and the reticle chamber 15.
8 on one side in the X direction (+ X side). The reticle transfer chamber RI and the structure of the transfer system and the like inside the reticle transfer chamber RI will be described later in detail.

The projection optical system PL is a system in which a lens made of a fluoride crystal such as fluorite or lithium fluoride or an optical system made of a reflecting mirror is sealed with a lens barrel. For the projection optical system PL, the projection magnification β is, for example, 1/4 or 1 /
Five reduction optical systems are used. For this reason, as described above, when the reticle R is illuminated by the exposure light EL from the illumination optical unit IOP, the pattern formed on the reticle R is reduced and projected onto the shot area on the wafer W by the projection optical system PL. Is formed.

The projection optical system PL includes a refraction system,
Both a catadioptric system and a reflective system can be used.

In the exposure apparatus using the exposure wavelength in the vacuum ultraviolet region as in the present embodiment, the gas inside the lens barrel of the projection optical system PL is also required to prevent the exposure light from being absorbed by the absorbing gas such as oxygen. It must be replaced with a low-absorbing gas. For this reason, in the present embodiment, the inside of the lens barrel of the projection optical system PL is
Filled with the low-absorbent gas, the pressure of which is 1 to atmospheric pressure
It is set about 10% higher.

More specifically, as shown in FIG. 1, an air supply valve 30 and an exhaust valve 31 are provided in the lens barrel of the projection optical system PL. As shown in FIG. 2, the air supply valve 30 is provided near an end of the air supply pipe connecting the lens barrel of the projection optical system PL and one end of the third chamber of the gas supply device 50 on the projection optical system PL side. Is provided. The exhaust valve 31 is provided near an end of the exhaust pipe connecting the lens barrel of the projection optical system PL and the other end of the third chamber of the gas supply device 50 on the projection optical system PL side. The control device (not shown) controls the air supply valve 3
0, by appropriately controlling the opening and closing of the exhaust valve 31 and the operation and stop of the pump incorporated in the third chamber of the gas supply device 50, the low absorption gas is filled in the lens barrel of the projection optical system PL, The concentration of the absorptive gas inside the lens barrel is less than several ppm. It should be noted that the low-absorbing gas may always flow in the lens barrel of the projection optical system PL. Also,
In the third chamber of the gas supply device 50, a gas purification device having the same function as the gas purification device built in the first chamber is built. Due to the operation of the gas purifying device, even if the low-absorbent gas is circulated for a long time through the circulation path including the third chamber of the gas supply device 50 and the inside of the lens barrel of the projection optical system PL, the inside of the lens barrel is not affected. Can be maintained at a concentration of several ppm or less.

The wafer stage WST includes a wafer chamber 4
0. The wafer chamber 40 is covered by a partition wall 41 joined to the lens barrel of the projection optical system PL without any gap, and the gas inside the wafer chamber 40 is isolated from the outside. The partition wall 41 of the wafer chamber 40 is formed of a material with little outgas such as stainless steel (SUS).

In the wafer chamber 40, a base BS is horizontally supported via a plurality of vibration isolating units 39. This anti-vibration unit 39 insulates vibrations at the micro G level in order to suppress transmission of vibrations due to movement of wafer stage WST to projection optical system PL and reticle R.
It should be noted that a so-called active vibration isolator for actively damping the base BS based on the output of a vibration sensor such as a semiconductor accelerometer fixed to a part of the device may be used as the vibration isolation unit 39. It is.

The wafer stage WST is moved along the upper surface of the base BS in a non-contact manner by a wafer drive system (not shown) including a magnetic levitation type linear motor or the like.
It is designed to be driven freely in the Y plane.

A wafer holder 35 is mounted on wafer stage WST, and wafer W is held by wafer holder 35 by suction. -X on wafer holder 35
At the end on the side, an X movable mirror 36X composed of a plane mirror is extended in the Y direction. The measuring beam from the X-axis laser interferometer 37X is projected almost vertically onto the X moving mirror 36X,
The reflected light is received by a detector inside the laser interferometer 37X, and the position of the X movable mirror 36X, that is, the X position of the wafer W is detected with reference to the position of a reference mirror provided at a predetermined position.

Similarly, although not shown, a Y-moving mirror formed of a plane mirror extends in the X direction at the + Y side end of the wafer holder 35. Then, the position of the Y movable mirror, that is, the Y position of the wafer W is detected by a Y-axis laser interferometer (not shown) through the Y movable mirror in the same manner as described above. The detected values (measured values) of the two laser interferometers are supplied to a control device (not shown).

The controller drives the wafer stage WST in the XY plane via a wafer drive system (not shown) while monitoring the detection values of these laser interferometers, thereby retrieving a plurality of shot areas on the wafer W. An inter-shot stepping operation for sequentially positioning the projection position (exposure position) of the pattern, and the emission of the light source 1 or the opening and closing of a shutter (not shown) in the light source 1 are controlled at each positioning, and the exposure light EL controls the reticle R An exposure operation of a step-and-repeat method is repeated in which an operation of transferring a reduced image of the pattern to each shot area via the projection optical system PL is performed.

In the exposure apparatus using the vacuum ultraviolet exposure wavelength as in the present embodiment, the optical path from the projection optical system PL to the wafer W is also required to avoid the exposure light being absorbed by an absorbing gas such as oxygen. It is necessary to replace with the low absorption gas. Therefore, in the present embodiment, the inside of the wafer chamber 40 is filled with the low-absorbent gas, and the pressure is set to be about 1 to 10% higher than the atmospheric pressure.

More specifically, an air supply valve 32 and an exhaust valve 33 are provided in the partition wall 41 of the wafer chamber 40 as shown in FIG. As shown in FIG. 2, the air supply valve 32 is provided near an end of the air supply line connecting the wafer chamber 40 and one end of the fourth chamber of the gas supply device 50 on the wafer chamber 40 side. The exhaust valve 33 is connected to the wafer chamber 40.
An exhaust pipe connecting the gas supply device 50 and the other end of the fourth chamber is provided in the vicinity of an end on the wafer chamber 40 side. Then, a control device (not shown) controls the opening and closing of the supply valve 32 and the exhaust valve 33 and the operation and stop of the pump incorporated in the fourth chamber of the gas supply device 50 as appropriate.
Is filled with a low absorption gas, and the concentration of the absorption gas in the wafer chamber 40 is suppressed to a concentration of several ppm or less. In addition,
A low-absorbency gas may be constantly flowed into the wafer chamber 40. In the fourth chamber of the gas supply device 50,
A gas purifier having the same function as the gas purifier built in the first chamber is built in. Due to the operation of the gas purifying device, even if the low-absorbing gas is circulated for a long time through the circulation path including the fourth chamber of the gas supply device 50 and the inside of the wafer chamber 40, the absorption in the wafer chamber 40 is reduced. The concentration of the gas can be maintained at a concentration of several ppm or less.

Next, the reticle R and its peripheral components will be described in detail with reference to FIGS. 1, 2, 3A, and 3B and FIGS. 4A and 4B.

In the exposure apparatus 100, as shown in FIG. 1, the pellicle frame 7 as a frame is placed on the reticle holder 14 on its pattern surface (the lower surface in FIG. 1).
6 and a reticle R to which a pattern protection device 72 (see FIG. 3 (B)) is attached, which is composed of a pellicle 75 as a pattern protection material attached to the side opposite to the pattern surface of the pellicle frame 76; Used for exposure.

As shown in the plan view of FIG. 3A, the reticle holder 14 is a holder main body 14a formed of a substantially square frame-like member having a rectangular opening 114 smaller than the reticle R at the center thereof. And the holder body 14a
Four vacuum suction mechanisms (vacuum chucks) 63A to 63D (shown as the vacuum suction mechanism 63 in FIG. 1) are provided one each near the four corners of the upper surface.
The reticle holder 14 can be finely driven (including rotation) in an XY plane by a reticle drive system (not shown). The reticle drive system can be configured to include, for example, two sets of voice coil motors.

The reticle R is sucked and held near the four corners thereof by the four vacuum suction mechanisms 63A to 63D. The suction surfaces of the vacuum suction mechanisms 63A to 63D are formed of a material such as Lulon, Teflon (registered trademark), or ceramic.

As shown in FIG. 3B, which is a cross-sectional view taken along the line AA of FIG. 3A, the reticle R has a fine pattern formed on one surface (the lower surface in FIG. 3B). And a reticle substrate 54 as a mask substrate. The reticle substrate 54 is made of a material mainly composed of quartz, for example,
It is formed of fluorine-doped quartz containing about 1% of fluorine by eliminating hydroxyl groups to about 10 ppm or less. The reason why such a material is used as the reticle substrate 54 is that light in a so-called vacuum ultraviolet region having a wavelength of 190 nm or less used as exposure light is not only gas such as oxygen and water vapor,
This is because a material having a high transmittance to vacuum ultraviolet light must be used because the transmittance in glass or an organic substance is low.

A pattern protection device 72 for protecting the circuit pattern is attached to the lower surface (hereinafter, referred to as "pattern surface") 54a of the reticle substrate 54. As shown in FIG. 3 (B), the pattern protection device 72 is a frame formed of a rectangular (substantially square) frame-shaped metal (aluminum, an alloy thereof, or the like) adhered to the pattern surface 54a of the reticle substrate 54. Pellicle frame 76
And a pellicle 75 as a pattern protection material adhered to the surface of the pellicle frame 76 opposite to the pattern surface 54a of the reticle substrate.

The pellicle 75 is mounted at a position about 6 mm away from the pattern surface of the reticle substrate 54 via a pellicle frame 76. The pellicle 75 is, for example, a thin film made of a fluorine-containing resin, or fluorite, magnesium fluoride, lithium fluoride, or the like made of the same material as the reticle substrate and the lens, in order to more appropriately transmit the exposure light EL in the vacuum ultraviolet region. A thin plate having a thickness of about 100 to 300 μm made of the above crystalline material can be used. When near-ultraviolet light is used as the exposure light, a transparent thin film made of an organic substance containing nitrocellulose or the like as a main component can be used.

In this case, a space (hereinafter, referred to as a “protection space”) PS surrounded by the pattern protection device 72 and the reticle substrate 54 is hermetically sealed. Adhesion and accumulation of dust and chemical dirt on the surface are prevented. However, since the pellicle 75 is formed of an extremely thin thin film, the permeability of ordinary gas molecules is high, and an absorbing gas such as oxygen or water vapor enters the protection space PS.
May accumulate. Therefore, in the present embodiment, during the exposure operation, that is, during the operation in which the pattern formed on the reticle R by the exposure light EL is transferred to the wafer W via the projection optical system PL, the gas in the protection space PS is reduced. The gas is replaced by an absorbent gas.

As shown in FIG. 3A, the square corners (four corners) of the pellicle frame 76 have an appropriate curvature with an inner surface having a radius of curvature of about 3 mm to 10 mm. 0.5mm to 3mm in corner
Vent holes 77A, 77B and 77C, 77D of about mm are formed respectively. In the ventilation holes 77A and 77B,
A gas supply system and a gas exhaust system constituting the low-absorbent gas circulation system 90 (see FIG. 2) shown in FIG. 2 are connected to each other.

As shown in FIG. 2, the low-absorbent gas circulation system 90 includes a gas supply device 20 and the gas supply device 20.
Air supply pipe 66 having one end connected to the inflow port (return port) of the pellicle frame, and a detachable mechanism 51A provided at the other end of the air supply pipe and removably attachable to a corner portion of the pellicle frame 76 where the ventilation hole 77A is formed. (This will be described in detail later), an exhaust pipe 78 having one end connected to the outlet (discharge port) of the gas supply device 20, and an exhaust pipe 78 provided at the other end of the exhaust pipe.
The pellicle frame 76 is provided with a detachable mechanism 51B and the like which can be detachably attached to a corner portion where the vent hole 77B is formed. The air supply pipe 66 and the exhaust pipe 78 have a flow control valve 5
5 and 56 are provided respectively. Gas supply device 20
Although the inside is not divided into a plurality of rooms, it is configured similarly to the gas supply device 50 described above. That is, the gas supply device 20 incorporates a storage tank, a pump, a gas purification device, and the like (all not shown) for the low-absorbent gas.

In this embodiment, the gas supply device 20, the air supply pipe 66, the flow control valve 55, and the desorption mechanism 51A
A gas supply system (and a second gas supply system) for supplying a low-absorbent gas into the protection space PS is configured. In addition, a gas exhaust system that exhausts the gas in the protection space PS to the outside is configured by the exhaust pipe 78, the flow control valve 56, and the desorption mechanism 51B.

Here, the configuration and the like of the detachable mechanisms 51A and 51B will be described. The detachment mechanism 51A is shown in FIG.
As shown in FIG. 4B, a telescopically variable member 64 made of a metal bellows such as aluminum provided at an end of the air supply pipe 66 opposite to the gas supply device 20 side,
Another air supply pipe 61 having a funnel-shaped tip connected to an end of the variable expansion / contraction member 64 opposite to the air supply pipe 66.
And a slide mechanism for reciprocating this in the axial direction of the air supply pipe 61 at an angle of approximately 45 ° with respect to the XY axes (hereinafter also referred to as “slide axial direction” for convenience).

More specifically, as shown in the enlarged plan view of FIG.
The end opposite to the zero side is fixed to the upper surface of the reticle holder 14 by a fastener 65. A flange 62 is integrally formed on the outer periphery of the air supply pipe 61 near an end opposite to the tip end thereof, and the flange 62 is formed in the XY plane in the axial direction of the air supply pipe 61. A pair of orthogonal support rods 6
7A and 67B protrude. These support rods 67
A and 67B are reciprocally driven by a drive mechanism (not shown) along slide guides 68A and 68B arranged along the slide axis direction on both sides of the air supply pipe 61 and the expansion / contraction variable member 64 on the upper surface of the reticle holder 14. It has become. Guide grooves 86a, 86b for guiding the support rods 67A, 67B are provided in the slide guides 68A, 68B.
Are formed respectively.

Further, the distal end portion 61a of the air supply pipe 61 is arranged as shown in FIG.
As shown in (B), the front surface 71 has a rectangular planar shape so that it can be in close contact with the outer surface of the corner of the pellicle frame 76. Also, as shown in FIG.
An annular concave groove (not shown) is formed on the distal end surface 71 surrounding the opening 74 formed at the distal end of the air supply pipe 61, and a sealing member 73 such as an O-ring is embedded in the concave groove by about half. It is fixed in the state where it was put. As the seal member 73, it is desirable to use, for example, a member made of fluorine rubber or the like, which hardly generates degassing of the absorbent gas.

The detachable mechanism 51 constructed as described above
According to A, in the non-use state, the air supply pipe 61 is connected to the air supply pipe 61 in FIG.
It is in the position shown in. Then, when the reticle R (mask device) on which the pattern protection device 72 is mounted is loaded on the reticle holder 14, the air supply pipe 61 is moved by the driving mechanism (not shown) in the direction of arrow B in FIG. Slide guides 68A, 68 via 67A, 67B
4A, the telescopically variable member 64 is extended, and the distal end surface 71 of the distal end portion 61a of the air supply pipe 61 is connected to the vent hole (air supply hole) of the pellicle frame 76, as shown in FIG.
77A is pressed against the corner portion where it is formed. At this time, the pellicle frame 7 is
Adhesion (airtightness) between the air supply tube 6 and the distal end surface 71 of the air supply pipe 61 is good.

On the other hand, when shifting from the used state to the non-used state, the supply pipe 61 is moved by the driving mechanism (not shown) in the direction of arrow B 'in FIG.
4A, the distal end surface 71 of the distal end portion 61a of the air supply pipe 61 is separated from the pellicle frame 76 as shown in FIG. I do.

That is, in this manner, the detaching mechanism 51
By A, the gas supply system is attached to and detached from the corner of the pellicle frame 76 where the ventilation hole (air supply hole) 77A is formed.

The attachment / detachment mechanism 51B includes the attachment / detachment mechanism 51 described above.
The gas exhaust system is attached to and detached from the corner portion of the pellicle frame 76 where the ventilation hole (air supply hole) 77B is formed in the same manner as described above, although the structure is the same as that of FIG. Is done.

Pellicle frame ventilation holes 77C, 77D
Of the remaining corners in which the gas is formed, one of the corners in which the vent hole 77C is formed is provided with a gas constituting the low-absorbent gas circulation system 90 through a desorption mechanism similar to the desorption mechanism 51A described above. The supply system is attached and detached, and the ventilation holes 7
A gas exhaust system that constitutes the low-absorbent gas circulation system 90 is attached to and detached from the other corner where the 7D is formed via a detachment mechanism similar to the detachment mechanism 51B described above.

In the exposure apparatus 100 of this embodiment, the protection space PS for the reticle R mounted on the reticle holder 14
When performing gas replacement in the inside, a drive mechanism (not shown) is controlled by a control device (not shown), and as shown in FIG. Are connected to corresponding corner portions of the pellicle frame 76, respectively. Then, the control device controls the gas supply device 20 constituting the low-absorbent gas circulation system 90, the flow rate regulating valves 55 and 56, etc., and supplies the low-absorbent gas to the protection space PS and from the protection space PS. Exhaust is performed. At this time, the control device maintains the differential pressure between the reticle chamber 15 and the protection space PS constant while monitoring the output of a barometer (not shown) provided in the reticle chamber 15. in this case,
While the pressure in the reticle chamber 15 can be measured by the above-mentioned barometer (not shown), it is very difficult to measure the pressure in the protection space PS. For this reason, in the present embodiment, the pressure of the gas supplied into the protection space PS is set to be slightly more positive than the pressure of the reticle chamber 15 measured by the barometer, and the pressure of the gas discharged from the protection space PS is set. Is set to a slightly lower pressure than the atmospheric pressure of the reticle chamber 15 to keep the differential pressure substantially constant.

As described above, the exposure apparatus 1 of the present embodiment
In 00, a low-absorbing gas with low absorption for light belonging to the vacuum ultraviolet region, for example, a rare gas such as nitrogen or helium is supplied into the protection space PS, and the gas inside the protection space PS is discharged to the outside ( Gas replacement in the protection space PS is performed). In this case, it is desirable that the concentration of the absorbing gas contained in the low-absorbing gas supplied from the gas supply device 20 into the protection space PS be suppressed to about several ppm or less. It is desirable that the concentration of impurities (such as an absorptive gas) be kept lower than that of the gas supplied from 50 to the reticle chamber 15 or the like.

On the other hand, when the reticle R is replaced, the control device controls the gas supply device 20 and the flow control valves 55 and 56 constituting the low-absorbency gas circulation system 90, and the supply and exhaust are stopped. . Thereafter, the drive mechanism is controlled by the control device, and the distal ends of the air supply pipe 61 and the exhaust pipe 81 are separated from the pellicle frame 76. As a result, the reticle R can be replaced by a transport system described below in the same manner as in the related art.

Next, the structure of a transfer system and a reticle transfer chamber RI for accommodating the transfer system will be described with reference to FIG.

As shown in FIG. 6, reticle chamber 1
5, the reticle transfer chamber RI described above is provided. In the partition wall 18 of the reticle chamber 15 forming the reticle transfer chamber RI, an entrance 18a is formed on a side wall on one side in the X direction (+ X side). This doorway 1
8a has a structure that can be opened and closed by a door 121. In addition, an entrance 125a is formed in a side wall on one side (+ X side) in the X direction of the partition 125 that forms the reticle transfer chamber RI together with the partition 18.
The door can be opened and closed by a door 122. Door 12
1, 122 are controlled to open and close by a control device (not shown) via a drive system (not shown).

The partition wall 125 of the reticle transfer chamber RI has an air supply valve 123 and an exhaust valve 124 at its ceiling and bottom.
Are provided respectively. As shown in FIG. 2, the air supply valve 123 is connected to one end of the fifth chamber of the gas supply device 50 through an air supply line, and the exhaust valve 124 is connected to the gas supply device 50 through an exhaust line. Is connected to the other end of the fifth chamber.

The control device (not shown) controls the air supply valve 12
3. The opening and closing of the exhaust valve 124 and the fifth of the gas supply device 50
By appropriately controlling the operation and stop of the pump incorporated in the chamber, the low-absorbent gas is filled in the reticle transfer chamber RI, and the concentration of the absorbent gas in the reticle transfer chamber RI is several pp.
m or less. The gas replacement method in the reticle transfer chamber RI will be further described later.

In the fifth chamber of the gas supply device 50,
A gas purifier having the same function as the gas purifier built in the first chamber is built in. Due to the operation of the gas purification device, even if the low-absorbent gas is circulated for a long time by the circulation path including the fifth chamber of the gas supply device 50 and the inside of the reticle transfer chamber RI, the inside of the reticle transfer chamber RI can be used. The concentration of the absorbing gas can be maintained at a concentration of several ppm or less.

Returning to FIG. 6, a reticle loader 120 as a transfer system composed of an articulated robot for loading and unloading the reticle R into and out of the reticle chamber 15 through the entrance 18a is arranged inside the reticle transfer chamber RI. I have.
On the + X side of reticle loader 120, reticle case mounting table 152 is provided. A reticle case 127 is mounted on a predetermined position on the reticle case setting table 152.

In this case, as the reticle case 127, a closed reticle carrier having an openable and closable door 127a is used. The door 127a is opened and closed by an opening and closing mechanism (not shown).

In the vicinity of the reticle loader 120 in the reticle transfer chamber RI, a vertical movement mechanism 153 fixed to the bottom surface is provided.
Elevator unit 160 having a shaft 151 which can be moved up and down by means of a shaft, and a support base 154 fixed to the upper end of the shaft.
Is provided. On the upper surface of the support base 154, a concave portion capable of accommodating the pattern protection device 72 attached to the reticle R held by the reticle loader 120 is formed. Also, on the upper surface of the support base 160, a detachment mechanism 51 having the same structure as the detachment mechanisms 51A and 51B described above.
A ′ and 51B ′ are provided in the same arrangement as in FIG. 3A. As shown in FIG. 2, each of the desorption mechanisms 51A 'is provided at one end of an air supply line 152A, and the other end of the air supply line 152A is provided with a gas supply device similar to the gas supply device 20 described above. Each is connected to the outlet of the device 20 '. In addition, each detaching mechanism 51B '
As shown in the figure, one end of the exhaust pipe 152B is provided, and the other end of the exhaust pipe 152B is connected to the return port of the gas supply device 20 '. Air supply line 1
52A, the flow control valves 83, 85 are provided in the exhaust pipe 152B.
Are provided respectively. As described above, two air supply lines 152A and two exhaust lines 152B are provided, respectively. However, in FIG. 6, only the air supply line 152A and the exhaust line 152B located on the near side in the drawing are shown. I have.

In the present embodiment, as shown in FIG.
The gas supply device 20 ', a pair of air supply pipes 152A, a pair of flow control valves 83, a pair of desorption mechanisms 51A', a pair of exhaust pipes 152B, a pair of flow control valves 85, and a pair of desorption mechanisms 51B ' In the transport path of the reticle R by the reticle loader 120, an air supply pipe and an exhaust pipe are respectively connected to corners of the pellicle frame 76 where the ventilation holes 77A to 77D are formed, and low absorption inside the protection space PS. A low-absorbing gas replacement system 91 similar to the above-described low-absorbing gas circulating system is configured to supply an inert gas and exhaust the gas in the protection space PS. In this case, the gas supply device 20 'and the air supply line 152
The gas supply system (and the first gas supply system) that supplies the low-absorbent gas into the protection space PS is constituted by A, the flow control valve 83, and the desorption mechanism 51A '.

Next, a series of operations from the start of loading of the reticle case 127 accommodating the reticle R in the reticle transfer chamber RI to the loading of the reticle R into the reticle chamber 15 (reticle loading) will be described. The operation of each of the following units is realized by the control operation of a control device (not shown), but the description of the control device is omitted here for simplification of the description.

First, a reticle case 127 containing a reticle R is taken out from a reticle library (not shown) arranged outside the reticle transfer chamber RI by a transfer system (not shown), and transferred to the reticle transfer chamber RI. Is started. Here, the inside of the reticle case 127 and the inside of the protection space PS surrounded by the pattern surface of the reticle R and the pellicle frame 76 and the pellicle 75 are pre-filled with a low-absorbent gas.

When the transfer system holding the reticle case 127 approaches the reticle transfer chamber RI within a predetermined distance, the door 122 is opened. At this time, the entrance 1 at the boundary between the reticle transfer chamber RI and the reticle chamber 15
8 a is closed by a door 121. Then, the transfer system holding the reticle case 127 enters the reticle transfer chamber RI, places the reticle case 127 on the reticle case setting table 152, and then retreats from the reticle transfer chamber RI (at the same time as the door). 122 is closed).

Next, the inside of the reticle transfer chamber RI is filled with the air supply valve 12.
3. When the gas is replaced through the exhaust valve 124 and the low-absorbent gas reaches a predetermined purity, the door 127a of the reticle case 127 is opened by an opening / closing mechanism (not shown). Subsequently, the reticle R is taken out of the reticle case 127 by the reticle loader 120 and transported toward the reticle chamber 15.

Here, the reticle transfer chamber RI of this embodiment is used.
Inside, while the reticle R is being conveyed from the reticle case 127 into the reticle chamber 15, the gas in the protection space PS is replaced.

That is, when the reticle R is transported to the position shown in FIG. 6 by the reticle loader 120, the support base 154 is moved via the shaft 151 by the drive mechanism 153 constituting the elevator unit 160 to the position shown in FIG. To rise. Next, the reticle loader 120 holds the desorption unit 51A ′ provided in each of the air supply lines 152A constituting the low-absorbency gas replacement system 91 and the desorption unit 51B ′ provided in each of the exhaust lines 152B. The reticle R is connected to opposing corner portions of the pellicle frame 75 on the lower surface thereof. Of course, this connection is made by the drive mechanism constituting each of the detachable units, the leading end of each of the air supply pipelines 152A and each of the exhaust pipelines 152B is driven in a predetermined direction, respectively, to the opposite corners of the pellicle frame 75. It is performed by being brought into close contact.

Then, the gas replacement in the protection space PS is performed in the same manner as the gas replacement by the low-absorbency gas circulation system 90 in the reticle chamber 15 described above. This gas replacement is continued until a predetermined criterion for ending the gas replacement is reached, for example, until a predetermined time elapses or until the concentration of the absorbent gas contained in the discharged gas becomes equal to or lower than a predetermined value.

When the gas replacement is completed, the desorption units 51 provided in each of the air supply lines 152A are provided.
A ′, the connection of the detachable unit 51B ′ provided in each exhaust pipe 152B to the opposing corner of the pellicle frame 75 is released. Then, after the support base 154 of the elevator unit 160 is driven downward,
The reticle R is transported toward the reticle chamber 15 by the reticle loader 120. And the reticle R is the door 1
When a predetermined distance is approached from the door 21, the door 121 is opened. Then, reticle loader 1 holding reticle R
20 enters the reticle chamber 15 via the entrance 18a, loads the reticle R on the reticle holder 14, and returns to the reticle transfer chamber RI. Thereafter, the door 121 is closed.

The operation of unloading the reticle R from the reticle chamber 15 is performed in a procedure opposite to the above-described loading operation except for gas replacement.

As is apparent from the above description, in the present embodiment, the pattern protection device 72 is constituted by the pellicle frame 76 and the pellicle 75, and the pattern protection device 72 and the reticle R (the reticle on which the circuit pattern is formed) The substrate 54) constitutes a mask device.

As described in detail above, according to the exposure apparatus 100 of the present embodiment, the reticle holder 14
With the reticle R on which the pellicle 75 is mounted held on the pattern surface via the pellicle frame 76, the pattern surface of the reticle R and the pellicle frame 7 are kept.
The low-absorbing gas is supplied into the protection space PS surrounded by the pellicle 75 and the low-absorbing gas by the gas supply system (the gas supply device 20, the air supply pipe 66, and the flow control valve 55) constituting the low-absorbency gas circulation system 90. Is done. As a result, the gas in the protection space PS is replaced with the low-absorbing gas, and the gas replacement in the protection space PS, which has not been considered conventionally, can be performed. In the exposure apparatus 100, the illumination system housing 2,
The reticle chamber 15, the lens barrel of the projection optical system PL, and the inside of the wafer chamber 40 are constantly replaced with a low-absorbing gas, and the concentration of the absorbing gas in the gas is maintained at several ppm or less. Therefore, it is possible to easily realize gas replacement of the space on the entire optical path of the exposure light EL including the inside of the protection space PS, and to maintain the exposure light transmittance satisfactorily and stably.
As a result, in addition to maintaining the exposure power and improving the throughput, it is possible to maintain the pattern line width transferred onto the wafer W uniform.

In the exposure apparatus 100 of the present embodiment,
The low-absorbent gas circulation system 90 is a gas exhaust system (gas supply device 20, exhaust pipe 7) for exhausting the gas in the protection space PS to the outside.
8 and a flow control valve 56). For this reason, the gas in the protection space PS is positively exhausted to the outside by the gas exhaust system, so that the gas replacement efficiency when replacing the gas in the protection space PS with the low-absorbing gas can be improved.
Further, since the gas exhausted from the protection space PS by the gas exhaust system is exhausted outside the optical path of the exposure light EL, the protection space PS
Of the exposure light EL can be prevented from being contaminated by the gas flowing out of the nozzle. This makes it possible to more stably maintain the exposure power high.

In exposure apparatus 100, pellicle frame 76 for attaching pellicle 75 to reticle R is provided.
The shape of the mounting surface of the reticle R on the pattern surface is rectangular (substantially square), and ventilation holes (77A to 77D) are provided at each corner.
Then, the low-absorbent gas circulation system 90 supplies the low-absorbent gas into the protection space PS via the two vent holes 77A and 77D therein, and the remaining two vent holes 77B and 77C.
The gas in the protection space PS is exhausted via the. For this reason, by forming a gas flow positively in a corner portion where gas accumulation is likely to occur, the gas accumulation is eliminated and efficient gas replacement can be realized.

When reticle R is conveyed toward reticle holder 14 by reticle loader 120, the reticle R is provided in the air holes 77 A to 77 D provided at the corners of pellicle frame 56 in the conveyance path. The low-absorbent gas is supplied into the protection space PS by the gas supply system constituting the low-absorbent gas replacement system 91 via the predetermined two. Thus, the low-absorbent gas is supplied into the protection space PS not only after the reticle R is transported onto the reticle holder 14, but also during the previous transport path. Therefore, for example, the reticle transfer chamber RI
Even when the purity of the low absorptive gas inside is relatively low, the absorptive gas which causes a decrease in the transmittance of the exposure light is removed from the protective space PS
It can be excluded from inside (suppress the invasion of the absorbent gas into the protection space PS). As a result, it is possible to effectively maintain the transmittance of the exposure light EL.

Further, in this case, the gas is supplied from a supply hole (a predetermined two of the ventilation holes 77A to 77D) provided at the corner of the pellicle frame 76 where gas accumulation is likely to occur.
), It is possible to efficiently replace the inside of the protection space PS with a low-absorbing gas.

The mode of supplying and exhausting the low-absorbent gas into the protection space PS described in the above embodiment is an example, and the present invention is not limited to this.
That is, the same pattern protection device 72 as in the above embodiment is used.
For example, even when the reticle R equipped with the reticle is used, as shown in FIG. 7A, a pair of air holes 77A and 77B opposed to each other allows the low absorptive gas to enter the protection space PS. Supply holes, and the remaining set of ventilation holes 77
The low-absorbent gas circulation system 90 may be configured such that C and 77D are holes for exhausting the gas in the protection space PS to the outside. In such a case, the same operation and effect as the above embodiment can be obtained.

In the above embodiment, ventilation holes are formed at the four corners of the pellicle frame 76 having a substantially square mounting surface with respect to the reticle pattern surface, and two of these ventilation holes are connected to the protection space. The supply holes for the low-absorbent gas into the PS are used as the holes, and the remaining two are used as the exhaust holes for the low-absorbent gas from the protection space PS. However, the present invention is not limited to this. That is, the supply and exhaust of the predetermined gas (the low-absorbent gas in the above-described embodiment) to and from the protection space PS may be performed by using a hole provided at any place as long as it is a ventilation hole that connects the inside and the outside of the protection space PS. You may go through. For example, as shown in FIG. 7B, a hole 79A formed in the pellicle 75, a groove 79B formed in the reticle substrate 54 at a contact portion between the reticle substrate 54 and the pellicle frame 76, or a pellicle frame 76 is formed. This may be performed through the formed notch 79C or the like. Therefore, even when the vent hole is formed in the pellicle frame 76, it is not always necessary to provide the hole at the corner.

Further, the pellicle frame 76 includes
As shown in (B), a dust-proof filter 98 made of ceramic or an organic substance may be attached to each ventilation hole 77. In such a case, dust (particles) can be prevented from entering the protection space PS through the ventilation hole 77 by the dustproof filter 98. In this case, in order to maintain airtightness, the air supply pipe 6 described above is used.
1 and a seal member 73 such as an O-ring provided on the end surface of the exhaust pipe 81 are larger in size than the dustproof filter 98, and more specifically, all the contact portions of the seal member 73 with the pellicle frame 76 are dustproof. It is desirable that the size be large enough to directly contact the pellicle frame 76 without being blocked by the filter 98.

Further, the shape of the pellicle frame 76 is not limited to the rectangular shape (substantially square shape) as in the above embodiment, and the shape of the mounting surface on the pattern surface may be a hexagon, an octagon, or the like. A pellicle frame having a rectangular shape may be used. Even in such a case, it is desirable to provide a ventilation hole at each corner or at one or more specific corners selected from the viewpoint of suppressing the occurrence of gas accumulation. However, the shape of the frame for attaching the pellicle to the reticle used in the exposure apparatus according to the present invention may not be a polygon.

In the above-described embodiment, the running cost is reduced by circulating and using a low-absorbing gas similarly to the illumination system housing 2, the reticle chamber 15, the lens barrel of the projection optical system PL, and the wafer chamber. The gas replacement in the protection space PS of the reticle R placed on the reticle holder 14 is performed by a low-absorbent gas circulation system 90 including a gas supply system and a gas exhaust system.
It was done by. However, the present invention is not limited to this. For example, the gas exhausted from the protection space PS may be exhausted to the outside of the exposure apparatus via a piping system, or the interior of the protection space PS may be slightly wider than the reticle chamber 15 without particularly providing the gas exhaust system described above. The positive pressure may be applied, and the gas in the protection space PS may be naturally exhausted into the reticle chamber 15 through the ventilation holes 77B and 77D. Even in such a case, since the inside of the reticle chamber 15 is replaced with the low-absorbing gas, no particular problem occurs.

In the above embodiment, the protection space P
If the inside of S is at a slightly higher positive pressure than the reticle chamber 15, the gas in the protection space PS may permeate through the pellicle 75 itself and leak into the reticle chamber 15. At this time, when the type of gas supplied to the reticle chamber 15 (gas supplied from the gas supply device 50) and the type of gas supplied to the protection space PS (gas supplied from the gas supply device 20) are different. When these gases are mixed, the refractive index on the optical path becomes unstable. Therefore, it is desirable that the same gas be supplied to the reticle chamber 15 and the protection space PS to prevent the refractive index of the optical path from deteriorating and to suppress the deterioration of the imaging characteristics.

In the above embodiment, the low-absorbing gas is supplied from the two ventilation holes 77A and 77C provided in the pellicle frame 76, and the other two ventilation holes 77B and 77D are provided.
From the pellicle frame 76.
If more than one vent is provided, at least one of the vents may be used for gas supply and at least one of the remaining vents may be used for gas exhaust. good. Further, the number of ventilation holes is not particularly limited.

In the above embodiment, the illumination system housing 2, the reticle chamber 15, the projection optical system PL, the wafer chamber 40
Gas supply device 50 for replacing the gas in the space, and the protection space PS
Although the gas supply device 20 for performing gas replacement in the inside is separately provided, it is not always necessary to do so. That is, the gas is supplied from the same gas supply device, and the illumination system housing 2, the reticle chamber 15, the projection optical system PL, and the wafer chamber 40 are supplied.
Alternatively, gas replacement in the protection space PS may be performed.

In the above embodiment, the case has been described where the low-absorbing gas replacement system 91 for performing gas replacement in the protection space PS is provided in the reticle transfer route by the transfer system. Then, it is not always necessary to provide the low-absorbing gas replacement system 91 or the like. However, when such a low-absorbing gas replacement system 91 is provided, prior to the reticle exchange, the exposure is performed using one reticle before the reticle is replaced. Gas replacement may be performed. In such a case, the time from the end of reticle exchange to the start of exposure using the reticle can be shortened, and the throughput can be improved.

Note that, instead of the low-absorbency gas replacement system 91,
A gas supply system for supplying a low-absorbent gas into the reticle protection space PS held by the reticle loader may be provided.
In such a case, the gas in the protection space PS is naturally exhausted into the reticle transfer chamber RI via an exhaust vent provided in the pellicle frame 75.

The gas replacement in the protection space PS in the reticle transfer chamber RI can be performed during the transfer. In this case, the gas supply line 152A and the exhaust line 1
52B or a detaching mechanism provided at the end thereof may have a configuration adapted to this movement. For example, at least a part of the air supply line 152A, the exhaust line 152B, and the like may be formed of a variable-shaped member such as a bellows or a resin. It is desirable to coat the surface with a metal such as aluminum in order to prevent mixing into the inside.

When an energy beam in the near ultraviolet region such as ArF excimer laser light is used as the exposure light,
Since the near-ultraviolet energy beam passes through the air to some extent, it is not always necessary to replace the air in the optical path portion of all exposure light with a low-absorbing gas. However, organic substances have a strong absorption even in the near-ultraviolet energy beam. Therefore, in the protection space PS, the concentration of the organic substance as a predetermined gas is ppm level, more preferably ppb level. It is desirable to provide a clean, clean air. When an energy beam belonging to the near ultraviolet region is used for exposure light, the reticle chamber 15 described above does not need to be provided. In this case, the pressure in the protection space PS is controlled by monitoring the output of a barometer that measures the atmospheric pressure, setting the pressure of the supplied air to be slightly more positive than the atmospheric pressure, and controlling the pressure of the exhausted gas. Is slightly negative, it is possible to keep the pressure difference between the inside and outside of the protection space PS almost constant.

Although not explicitly stated in the above description, the interiors of the illumination system housing 2, the reticle chamber 15, the lens barrel of the projection optical system PL, the wafer chamber 40, and the like are the same as those of an environmental chamber (not shown). Temperature adjustment is performed with a degree of accuracy. Although not explicitly described above, portions of the illumination system housing 2 and the column of the projection optical system PL that come into direct contact with the low-absorbing gas are similar to the above-described partitions of the reticle chamber 15 and the wafer chamber 40. It is desirable to use a material with low degassing such as stainless steel (SUS). Alternatively, degassing of an absorbent gas such as a hydrocarbon is generated on a surface of a portion of the illumination system housing 2, the reticle chamber 15, the lens barrel of the projection optical system PL, the wafer chamber 40, and the like which is in direct contact with the low-absorbency gas. A coating such as a resin containing a small amount of fluorine may be applied.

In the above embodiment, the case where the present invention is applied to a reduction projection exposure apparatus such as a step-and-repeat method has been described. However, it is needless to say that the scope of the present invention is not limited to this. . That is, the present invention can be suitably applied to a step-and-scan type scanning exposure apparatus that relatively scans the reticle R and the wafer W during exposure. In this case, the reticle R and the reticle holder 1
4 is placed on a reticle stage (not shown) and scanned together with the reticle stage during the exposure operation, so that at least a part of the air supply pipe and the exhaust pipe is changed to a variable-shape tubular member corresponding to this scanning. Just do it. That is, a bellows formed of a sheet that can be expanded and contracted to such an extent that the reticle stage does not resist the movement of the reticle stage, for example, a sheet provided with an outgassing countermeasure may be used. This sheet may be made of various fluoropolymers such as ethylene tetrafluoride or tetrafluoroethylene-alkyl vinyl ether or tetrafluoroethylene-hexafluoropropene copolymer, or a single-layer silica-coated pet resin-polyethylene double-layer structure or nylon- A one-layer silica-coated pet resin-polyethylene having a three-layer structure can be used.

As described above, when the present invention is applied to the scanning type exposure apparatus, the gas inside the protection space PS can be constantly replaced during scanning exposure, that is, while the reticle stage is synchronously moved with the wafer stage. Therefore, even if the absorbing gas enters the protection space PS or the absorption gas is generated due to the chemical reaction due to the irradiation of the exposure light, the accumulation of the absorption gas in the protection space PS can be suppressed. .

The above-mentioned variable-shape tubular member may be formed of bellows or resin. When a resin is used for the tubular member, the resin material penetrates and an absorbent gas is mixed therein. It is desirable to coat the surface with a metal, such as aluminum, in order to prevent the occurrence of such a phenomenon.

As a levitation method of wafer stage WST, a method utilizing a levitation force by a gas flow instead of magnetic levitation can of course be adopted. In such a case, a gas supplied for levitation of the stage is used. It is desirable to use the same gas as the gas supplied into the wafer chamber 40.

The illumination optical system and the projection optical system composed of a plurality of lenses are incorporated in the main body of the exposure apparatus for optical adjustment, and a wafer stage (or a reticle stage in the case of a scan type) composed of many mechanical parts. Is attached to the exposure apparatus main body, and wiring and piping are connected.
5, assembling each partition and the like constituting the wafer chamber 40, FIG.
Connect the gas piping system including the low-absorbent gas supply system and exhaust system shown in (1), connect each part to the control system such as a control device, and make comprehensive adjustments (electrical adjustment, operation confirmation, etc.) Thus, an exposure apparatus according to the present invention, such as the exposure apparatus 100 of the above embodiment, can be manufactured. It is desirable that the manufacture of the exposure apparatus be performed in a clean room in which the temperature, cleanliness, and the like are controlled.

<< Device Manufacturing Method >> Next, an embodiment of a device manufacturing method using the above-described exposure apparatus in a lithography process will be described.

FIG. 8 shows a flowchart of an example of manufacturing devices (semiconductor chips such as ICs and LSIs, liquid crystal panels, CCDs, thin-film magnetic heads, micromachines, etc.). As shown in FIG. 8, first, step 201
In the (design step), a function / performance design of the device (for example, a circuit design of a semiconductor device) is performed, and a pattern design for realizing the function is performed. Continued
In step 202 (mask manufacturing step), a mask on which the designed circuit pattern is formed is manufactured. on the other hand,
In step 203 (wafer manufacturing step), a wafer is manufactured using a material such as silicon.

Next, in step 204 (wafer processing step), an actual circuit or the like is formed on the wafer by lithography or the like using the mask and the wafer prepared in steps 201 to 203, as described later. . Next, in step 205 (device assembly step), device assembly is performed using the wafer processed in step 204. In this step 205,
Steps such as a dicing step, a bonding step, and a packaging step (chip encapsulation) are included as necessary.

Finally, step 206 (inspection step)
In step S205, inspections such as an operation check test and a durability test of the device created in step 205 are performed. After these steps, the device is completed and shipped.

FIG. 9 shows a detailed flow example of step 204 in the semiconductor device. FIG.
In step 211 (oxidation step), the surface of the wafer is oxidized. In step 212 (CVD step), an insulating film is formed on the wafer surface. In step 213 (electrode formation step), electrodes are formed on the wafer by vapor deposition. In step 214 (ion implantation step), ions are implanted into the wafer. Each of the above steps 211 to 214 constitutes a preprocessing step in each stage of wafer processing.
At each stage, it is selected and executed according to necessary processing.

In each stage of the wafer process, when the above-mentioned pre-processing step is completed, the post-processing step is executed as follows. In this post-processing step, first, in step 2
In 15 (resist forming step), a photosensitive agent is applied to the wafer. Subsequently, in step 216 (exposure step), the circuit pattern of the mask is transferred onto the wafer by the exposure apparatus and the exposure method of each embodiment described above. Next, in step 218 (etching step), the exposed members other than the portion where the resist remains are removed by etching. Then, in step 219 (resist removing step), unnecessary resist after etching is removed.

By repeatedly performing the pre-processing step and the post-processing step, multiple circuit patterns are formed on the wafer.

If the device manufacturing method of the present embodiment described above is used, the exposure apparatus of the above embodiment is used in the exposure step (step 216). Productivity can be improved.

[0131]

As described above, according to the exposure apparatus of the present invention, there is an excellent effect that the exposure light transmittance can be maintained satisfactorily and stably.

Further, according to the mask device of the present invention,
There is an effect that the gas replacement efficiency can be improved.

Also, the pattern protection device according to the present invention
The present invention can be suitably applied to a mask protection device capable of improving the gas replacement efficiency.

Further, according to the device manufacturing method of the present invention, there is an effect that the productivity of a highly integrated device can be improved.

[Brief description of the drawings]

FIG. 1 is a view schematically showing a configuration of an exposure apparatus according to one embodiment.

FIG. 2 is a diagram schematically showing a gas piping system of the apparatus of FIG.

FIG. 3A is a plan view showing the reticle holder of FIG. 1 in a state where a reticle R is loaded, and FIG.
FIG. 4 is a sectional view taken along line AA of FIG.

FIG. 4A is a plan view showing a state of the air supply mechanism at the time of gas replacement, and FIG. 4B is a plan view showing a state of the air supply mechanism at the time of reticle replacement.

FIG. 5 is a view showing a structure of a distal end surface of an air supply pipe constituting the air supply mechanism of FIGS. 4 (A) and (B).

FIG. 6 is a longitudinal sectional view showing an example of a configuration in a case where a gas replacement system is provided in a reticle transfer chamber.

FIGS. 7A and 7B are diagrams for explaining a modified example.

FIG. 8 is a flowchart illustrating an embodiment of a device manufacturing method according to the present invention.

FIG. 9 is a flowchart illustrating a process in step 204 of FIG. 8;

[Explanation of symbols]

14 ... reticle holder (mask holding member), 20 ... gas supply device (part of gas supply system, part of second gas supply system), 20 '... gas supply device (part of first gas supply system) ), 51A: Desorption mechanism (part of gas supply system, part of second gas supply system), 51A ': Desorption mechanism (part of first gas supply system), 51B: Desorption mechanism (gas exhaust system) ), 54 ... reticle substrate (mask substrate), 54a ... pattern surface, 55 ... flow control valve (part of gas supply system, second
, A flow control valve (a part of a gas exhaust system), 66 ... an air supply pipe (a part of a gas supply system, a part of a second gas supply system), 75 ... a pellicle ( Pattern protector, 72 Pattern protector, 76 Pellicle frame (frame), 77A, 77B Vent, 78 Exhaust pipe (part of gas exhaust system), 83 Flow control valve (first gas supply) 98: dust filter, 100: exposure apparatus, 120: reticle loader (transport system), 152A ...
Air supply line (part of the first gas supply system), EL: exposure light (energy beam), PS: protection space (space), R: reticle (mask), W: wafer (substrate).

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) H01L 21/30 516F

Claims (12)

[Claims] An exposure apparatus for irradiating a mask with an energy beam and transferring a pattern formed on the mask onto a substrate, wherein the mask having a pattern protection material mounted on a pattern surface thereof via a frame. A mask holding member for holding; a predetermined space in a space surrounded by the pattern surface, the frame, and the pattern protection material in a state where the mask having the pattern protection material mounted on the mask holding member is held; An exposure apparatus comprising: a gas supply system that supplies gas. 2. The exposure apparatus according to claim 1, wherein the supply of the gas is performed through a supply vent formed in the frame. 3. The exposure apparatus according to claim 1, further comprising a gas exhaust system that exhausts gas in the space to the outside. 4. The exposure apparatus according to claim 3, wherein the exhaust of the gas is performed through an exhaust vent formed in the frame. 5. The frame according to claim 2, wherein a shape of a mounting surface to the pattern surface has a polygonal shape, and the ventilation hole is provided at a corner of the polygon. Or the exposure apparatus according to 4. 6. An exposure apparatus for irradiating a mask with an energy beam and transferring a pattern formed on the mask onto a substrate, the mask having a pattern protection material mounted on a pattern surface thereof via a frame. A transport system for transporting toward the mask holding member; and in the transport route of the mask by the transport system, the pattern surface, the frame, and the pattern protection material via supply holes provided in corner portions of the frame. And a first gas supply system for supplying a predetermined gas into a space surrounded by. 7. A second gas supply system which constantly supplies the predetermined gas into the space via the supply hole after the mask is loaded onto the mask holding member by the transport system. The exposure apparatus according to claim 6, further comprising: 8. A mask substrate having a circuit pattern formed on one surface thereof; a frame mounted on the pattern surface of the mask substrate having the circuit pattern formed thereon, the mounting surface having a polygonal shape; And a pattern protection member mounted on a surface opposite to the pattern surface, wherein a ventilation hole is provided in a corner portion of the frame. 9. The mask device according to claim 8, wherein the ventilation holes are provided in at least two or more corner portions of the frame. 10. The mask device according to claim 8, wherein a dust filter is provided in the ventilation hole. 11. A pattern protection device for protecting a circuit pattern by attaching the mask to a mask substrate on which a circuit pattern is formed, the pattern protection material having a predetermined thickness; A pattern protection device comprising: a frame attached to the mask substrate, the other surface serving as an attachment surface for the mask substrate, the attachment surface having a polygonal shape, and a ventilation hole formed at a corner thereof. 12. A device manufacturing method including a lithography step, wherein in the lithography step, exposure is performed using the exposure apparatus according to any one of claims 1 to 7. .