JP2004080052A - Method for manufacturing exposure apparatus and device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing an exposure apparatus and device capable of keeping clean the surface of an optical element and suppressing attached materials from depositing, by efficiently supplying a clean gas near the surface of the optical element, separated from ambient atmosphere, on the side near the ambient atmosphere; reducing the effect of the gas flow as much as possible on the imaging performance in imaging position adjustment; and efficiently preventing contaminations of the surface of the optical element with a very small amount of gas. <P>SOLUTION: The exposure apparatus is so configured that a gas supply means has two or more gas supply inlets; a gas exhaust means has two or more gas exhaust exits; and the gas is supplied in a local laminar flow with respect to the surface of a projected surface side of a final optical element, by supplying the gas to the surface of the projected surface side of the final optical element from the two or more gas supply inlets, and discharging the supplied gas from the two or more gas exhaust exits. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to an exposure apparatus and a method of manufacturing a device, for example, in an exposure apparatus using a wavelength in the ultraviolet region as a light source, in particular, in a semiconductor exposure apparatus or the like, which is suitable for preventing contamination of the surface of an optical element on the ambient atmosphere side that is separated from the ambient atmosphere. About technology.

Semiconductor integrated circuits have been miniaturized year by year, and accordingly, an exposure apparatus for transferring a circuit pattern onto a wafer has been required to have a capability of transferring a finer pattern. For this reason, the wavelength of the exposure light used in the exposure apparatus is gradually shortened. At present, i-line having a wavelength of 365 nm and KrF excimer laser light having a wavelength of 245 nm are mainly used. Further, 193 nm ArF excimer laser light has been used, and 157 nm F2 laser light has been studied.
These exposure apparatuses have the following configuration. Ultraviolet light from a lamp or laser passes through a beam shaping unit, is adjusted to a desired shape and brightness distribution by an illumination optical system including a secondary light source and a lens mirror system, and illuminates the reticle. The circuit pattern of the reticle is reduced to a desired magnification through the projection optical system and is transferred onto the wafer.

光学 Optical elements such as lenses and mirrors of the exposure apparatus often have deposits on the surface due to impurities contained in the surrounding atmosphere. It is known that typically, ammonium sulfate, silicon oxide and the like are formed on the surface of an optical element. These sources are ammonia vapor generated from concrete in a clean room, sulfuric acid used for stripping resist, sulfur oxides generally contained in the atmosphere, silicone resin used for wall materials, floor materials, etc. And so on. Further, inside the exposure apparatus, HMDS (hexadimethyldisilazane) or the like used as an adhesion enhancer between the wafer and the resist is considered. Therefore, a filter or the like is provided in an air circulation device or the like in order to remove impurities from the air in the clean room and the exposure device. However, since the inside of the exposure apparatus has many components other than the optical element, and the gas generated from the resist can also cause the deposit, it is difficult to completely remove the impurity gas that causes the deposit. For this reason, contamination of the optical element is prevented by storing the optical element in a container for each unit, isolating the optical element from the environment of the surrounding exposure apparatus chamber, and purging the interior with a gas containing no impurities.

However, it is difficult to purge the entire optical path of the exposure light. In particular, since the stage moves around the reticle and around the wafer, it is difficult to purge only the optical path from the surrounding atmosphere. In addition, the optical path between units may pass through the surrounding atmosphere. Optical elements that separate the surrounding atmosphere are placed at the entrance and exit of the container for each unit, but the surface of these optical elements on the side of the surrounding atmosphere is exposed to an atmosphere containing impurities, so that deposits are generated. I do. For this reason, optical performance degradation such as a decrease in illuminance occurs, and regular cleaning or replacement is indispensable.
In particular, the optical element closest to the wafer in the projection optical system is exposed to the gas generated from the resist, and thus has a problem in that the transmittance is significantly deteriorated. For this reason, as shown in FIG. 2, means such as flowing gas in one direction in the space between the wafer and the lens are used. In the exposure apparatus, the fluctuation of the atmosphere affects the imaging performance.
Further, in the scanning type exposure apparatus, since the stage moves, gas from the resist is easily entrained, and the impurity concentration on the lens surface cannot be effectively reduced.
However, in this method, the gas component generated from the wafer is carried to the lens surface by the flow of the gas, and the contamination cannot be sufficiently prevented. Japanese Patent Application Laid-Open No. Hei 6-26038 discloses a method in which an inert gas is supplied in parallel to a wafer from a supply port provided on a stage, and at the same time, a gas is supplied from the lower end of the projection optical system toward the wafer in parallel with the optical axis. It is shown. This method focuses on the oxygen concentration in the space from the projection optical system to the wafer, and is not efficient in preventing contamination of the lower surface of the projection system. Meter-side light for measuring the imaging position passes between the projection system lens and the wafer surface. A change in the temperature or pressure in the atmosphere in the space through which the meter-side light passes causes a measurement error, and greatly affects the adjustment of the position of the wafer to the image forming position. Further, changes in the temperature and pressure of the atmosphere also affect the imaging performance. For this reason, the flow of the gas at a large flow rate and the fluctuation of the pressure and the temperature cause the misalignment of the wafer position and the deterioration of the imaging performance.

Therefore, the present invention solves the above-mentioned problems in the conventional device, and keeps the surface of the optical element clean by efficiently supplying a clean gas to the vicinity of the surface of the optical element which is separated from the surrounding atmosphere on the side of the surrounding atmosphere. In addition, it is possible to suppress the deposition of deposits, and to minimize the influence of the flow of the gas on the adjustment of the imaging position of the imaging performance. An object of the present invention is to provide an exposure apparatus and a device manufacturing method that can prevent contamination of the surface of an optical element.

An object of the present invention is to provide an exposure apparatus and a device manufacturing method capable of preventing the surface of an optical element configured as described below from (1) to (17) to achieve the above object. .
(1) a projection optical system including a plurality of optical elements and projecting a pattern onto a projection target surface;
A lens barrel that houses the plurality of optical elements,
Of the plurality of optical elements, between the final optical element and the projection surface arranged at an opening position provided at a position closest to the projection surface of the lens barrel at a position closest to the projection surface. Gas supply means arranged to supply gas from one side of the projection optical system,
An exposure apparatus having a gas exhaust unit disposed on a side opposite to the one side and exhausting the gas,
The gas supply means has a plurality of gas supply ports, the gas exhaust means has a plurality of gas exhaust ports,
By supplying gas from the plurality of gas supply ports and exhausting the supplied gas from the plurality of gas exhaust ports with respect to the surface on the projection surface side of the final optical element, An exposure apparatus, wherein a gas is locally supplied to the surface on the projection surface side in a laminar flow.
(2) a cover surrounding the optical path of the projection optical system on the side of the projection surface of the final optical element, wherein the plurality of gas supply ports and the plurality of gas exhaust ports are provided in the cover; The exposure apparatus according to the above (1), wherein
(3) There is provided a chamber gas supply means for supplying a chamber gas into the lens barrel, wherein the chamber gas and the gas supplied by the gas supply means are of the same gas type. The exposure apparatus according to 2).
(4) The exposure apparatus according to any one of (1) to (3), wherein the gas supplied by the gas supply unit is an inert gas.
(5) The exposure apparatus according to (4), wherein the inert gas is nitrogen or helium.
(6) The exposure apparatus according to any one of (1) to (5), wherein the supply gas is air, and the impurity is removed by the impurity removing unit.
(7) The exposure apparatus according to any one of (1) to (6), further including a unit configured to remove impurities contained in a gas locally supplied to the optical element surface by the gas supply unit. .
(8) The exposure apparatus according to any one of (1) to (7), wherein the gas supplied to the gas supply unit is supplied from a gas supply facility having a unit for removing impurities.
(9) The exposure apparatus according to any one of (1) to (8), further including a unit that adjusts a gas supply flow rate and a pressure from the gas supply unit according to a use state of the exposure apparatus. .
(10) The exposure apparatus according to any one of (1) to (9), further including a unit that adjusts a gas discharge flow rate and a pressure from the gas discharge unit according to a use state of the exposure apparatus. .
(11) The exposure apparatus according to any one of (1) to (10), having a function of adjusting a temperature of a gas supplied from the gas supply unit.
(12) The exposure apparatus according to any one of (1) to (11), wherein light having a wavelength of ultraviolet light is used.
(13) The above (1) or (2), wherein the plurality of gas supply ports and the plurality of gas exhaust ports are respectively arranged in a direction substantially parallel to the projection surface. Exposure equipment.
(14) The method according to any one of (1) to (13), wherein the last optical element is an optical element opposed to a wafer disposed at a position of a projection surface of the projection optical system. Exposure equipment.
(15) a projection optical system including a plurality of optical elements and projecting a pattern onto a projection surface;
A lens barrel that houses the plurality of optical elements,
Of the plurality of optical elements, between the final optical element and the projection surface arranged at an opening position provided at a position closest to the projection surface of the lens barrel at a position closest to the projection surface. Gas supply means arranged to supply gas from one side of the projection optical system,
An exposure apparatus having a gas exhaust unit disposed on a side opposite to the one side and exhausting the gas,
A cover surrounding the optical path of the projection optical system on the projection surface side of the final optical element,
The gas supply means has a plurality of gas supply ports in the cover, the gas exhaust means has a plurality of gas exhaust ports in the cover,
An exposure apparatus, wherein a gas is supplied from the plurality of gas supply ports to a surface of the final optical element on the side of the projection surface, and the supplied gas is exhausted from the plurality of gas exhaust ports.
(16) a projection optical system including a plurality of optical elements and projecting a pattern onto a projection surface;
A lens barrel that houses the plurality of optical elements,
The gas is supplied from one side of the side surface of the final optical element disposed at an opening position provided at a position closest to the projection surface of the plurality of optical elements at a position closest to the projection surface of the lens barrel. Gas supply means;
An exposure apparatus having a gas exhaust unit disposed on a side opposite to the one side and exhausting the gas,
A cover surrounding the optical path of the projection optical system on the projection surface side of the final optical element,
The gas supply means has a plurality of gas supply ports on the cover, and the gas exhaust means has a plurality of gas exhaust ports on the cover.
An exposure apparatus, wherein a gas is supplied from the plurality of gas supply ports to a surface of the final optical element on the side of the projection surface, and the supplied gas is exhausted from the plurality of gas exhaust ports.
(17) A device manufacturing method including a step of exposing a wafer by the exposure apparatus according to any one of (1) to (16) and a step of developing the exposed wafer.

As described above, according to the present invention, the surface of the optical element is kept clean by efficiently supplying a clean gas to the vicinity of the surface on the peripheral atmosphere side of the optical element that is isolated from the surrounding atmosphere. It is possible to effectively prevent the deposition of the kimono, and it is possible to realize the prevention of contamination particularly suitable for a semiconductor exposure apparatus.
Further, according to the present invention, by adopting a configuration in which the gas flow direction and the flow rate are taken into consideration, such as arranging a plurality of gas supply ports and discharge ports in a rotating object, the influence on the imaging performance is small, and the lens The impurity concentration on the surface can be effectively reduced.
Further, according to the present invention, a gas supply port is provided on one of the side surfaces of the lens surface, an exhaust port is provided on the opposite side, and a configuration is adopted in which gas flows along the lens surface. However, the lens surface can be effectively kept locally in a clean atmosphere.
Further, when the present invention is applied to a scanning exposure apparatus, an apparatus which is less affected by scanning of a mask and a wafer stage or the like can be realized.

In the embodiment of the present invention, by applying the above-described configuration, a gas having a small amount of impurities causing an adhered substance is locally sprayed or flown in a laminar flow on the peripheral atmosphere side surface of the optical element. As a result, it is possible to supply the optical element, and the vicinity of the surface of the optical element is set as an atmosphere with few impurities so that the deposition of deposits can be suppressed. Becomes possible.
In addition, by applying the above configuration, by arranging a plurality of gas supply ports and discharge ports on the rotation target, the flow of the gas becomes the rotation target, the influence on the imaging performance is small, and the lens surface is not affected. Can be effectively reduced.
In addition, by applying the above configuration, an air supply port is provided on one of the side surfaces of the lens surface, an exhaust port is provided on the opposite side, and gas is flown along the lens surface, so that even a small amount of gas is effective. In addition, the lens surface can be locally kept in a clean atmosphere.

Hereinafter, examples of the present invention will be described.
[Example 1]
FIG. 1 is a schematic diagram showing the configuration of the first embodiment of the present invention, and is a typical configuration example of the present invention applied to the lowermost lens of a projection system of a semiconductor exposure apparatus.
FIG. 1A is a schematic sectional view of a projection lens barrel to which the present embodiment is applied, and FIG. 1B is a schematic diagram of a lower surface.
As shown in FIG. 1, the projection system of the semiconductor exposure apparatus is constituted by a plurality of lenses 2, and the entire optical system is housed in a sealed lens barrel 1 in which an atmosphere from a chamber atmosphere 10 does not flow. On the optical path, the uppermost part of the projection system, ie, the lens closest to the reticle, and the lowermost part of the projection system, ie, the lens 3 closest to the wafer, block the atmosphere.
The lens barrel is provided with a gas supply port 4 and a gas exhaust port 6, so that a clean gas containing no impurities therein can be supplied.
However, the top and bottom lenses are each exposed on one side to the atmosphere of the exposure apparatus chamber. For this reason, a plurality of gas supply ports 13 are arranged around the lowermost lens of the projection system so as to surround the lens around the optical axis of the lens.

The gas 15 ejected from the gas supply port flows toward the center of the lens along the surface of the lens, flows downward in the vicinity of the center, and diffuses. In order to create an effective flow, the flow rate, flow velocity, and the like must be controlled. For this reason, the optimum shape of the ejection port 15 and the flow velocity and pressure of the gas are determined according to the lens shape and size.
It is also effective to provide a cover 16 on the lower surface of the lens so as to prevent mixing of ambient atmosphere gas and to assist the flow of the supply gas.
The gas used must be clean and free of pollutants. Since organic substances, SOx, NOx, ammonia, and the like are pollution sources, an organic substance removing filter such as activated carbon for removing these organic substances, a chemical filter for removing inorganic substances, and the like are required.
The exposure apparatus may have an individual impurity removing device such as a filter, or a gas supplied from a factory or an experimental facility having an impurity removing function may be used.
The gas type is selected according to the wavelength of ultraviolet light used in the exposure apparatus, and the like. In the case of i-line and KrF lasers, the atmosphere may be used, but when light of a shorter wavelength is used, an inert gas such as nitrogen or He is used. When the inert gas is directly supplied from a commercially available high-purity cylinder or the like, the impurity gas, which is a polluting source, is hardly contained, so that the inert gas may be used without using an impurity removing device.
According to the above method, deposits on the lens surface are hardly observed. Since the gas is locally supplied toward the lens surface, the influence on the position measurement of the wafer is small, and in the scanning exposure apparatus, the influence of the diffusion of the resist gas due to the movement of the wafer stage or the like is reduced.

Further, by adjusting the flow rate adjusting valve 14 of the supply gas to adjust the gas flow rate according to the exposure state, it is possible to more effectively supply the clean gas to the lens surface. For example, during alignment, during imaging position measurement, and during exposure, the influence of the gas flow affects the imaging performance, so the flow rate of the flowing gas is limited. On the other hand, the gas flow rate can be increased during wafer transfer or the like. Therefore, when a new wafer is transferred to the wafer stage, the supply flow rate is increased, impurity gas generated from the resist is effectively removed from near the lens, and the flow rate is reduced during alignment and exposure so that the imaging performance is not affected. I do.
If it is possible to flow gas on the lens surface with the same gas type as that in the lens barrel, it is also possible to guide the gas from the exhaust port of the projection lens barrel as shown in FIG. is there.

[Example 2]
FIG. 4 shows a schematic diagram of the configuration of the second embodiment of the present invention. In the gas supply method of the first embodiment, the gas flowing from the lens to the wafer surface may diffuse on the wafer surface and diffuse the resist gas depending on the size and shape of the lens. In this case, the gas flow can be effectively created by forming the exhaust port 17 below the supply port as shown in FIG.
Also in this case, as in the case of the supply port, a plurality of exhaust ports are arranged rotationally symmetrically about the optical axis.
In addition, it is necessary to appropriately arrange the shapes and positions of the air supply port and the exhaust port so that the gas flow becomes an appropriate flow. Further, it is necessary to appropriately adjust the supply pressure and the flow rate and the exhaust pressure from the exhaust port. The pressure in the projection system barrel is kept constant, and the pressure difference from the surrounding atmosphere is usually small. On the other hand, it is necessary to exhaust air from the exhaust port 17 with a certain or more pressure difference from the surrounding atmosphere. In such a case, an exhaust system 33 separate from the projection system barrel is provided as necessary.

[Example 3]
FIG. 5 shows a schematic diagram of the configuration of the third embodiment of the present invention. FIG. 5A is a schematic sectional view of a projection lens barrel to which the present embodiment is applied. FIG. 5B is a schematic view of the lower surface of the lens.
A gas supply port 18 and an exhaust port 20 are provided in the lowermost part of the projection system, that is, the lens 3 closest to the wafer, and near the lens surface on the chamber atmosphere side of the lens barrel 22 in the upper part of the projection system, and a clean gas flows. As shown in FIG. 5B, by providing an air supply port 18 on one side of the lens and an exhaust port 20 on one side, it is possible to create a locally effective gas flow only on the lens surface. it can. In particular, it is effective to provide a plurality of supply ports and exhaust ports, since gas flows uniformly on the lens surface.

Further, the gas outflow angle at the gas supply port is optimally selected according to the shape (concave surface or convex surface or flat surface) of the lens and its curvature, so that the gas flows along the lens surface. In addition, by providing the cover 16 on the chamber atmosphere side of the lens, the influence of the flow of the surrounding gas and the mixing can be prevented.
The gas is adjusted to have a laminar flow by adjusting the flow rate and the flow velocity by using the flow control valve 19. In this method, the gas flows in one direction, but the atmosphere on the lens surface can be effectively kept clean with a small flow rate. Therefore, the influence on the imaging performance and the imaging position measurement is small. In addition, there is an advantage that it can be arranged in a relatively narrow space. Further, since the gas flows locally only on the lens surface, in the scanning exposure apparatus, the influence of the diffusion of the resist gas due to the movement of the wafer stage or the like is reduced.
Further, probe light for focus position measurement passes between the projection optical system and the wafer. If pressure or temperature unevenness occurs in the atmosphere through which the probe light passes, a measurement error occurs.
For this reason, the same gas type as that of the chamber atmosphere is usually used. However, in this embodiment, since the gas flow is stable, it is possible to flow another gas having a different refractive index from the atmospheric gas, for example, to flow nitrogen when the chamber atmosphere is the atmosphere. When the inside of the lens barrel is purged with the same gas type, piping may be performed using the same gas system. However, when a different kind of gas flows, another gas system is required. When the same gas system as the chamber atmosphere is used, the gas needs to be sufficiently clean. Therefore, a gas cleaning means such as inserting a filter is provided as necessary.

This embodiment is applicable not only to a projection system but also to a part of another optical system such as an illumination system as shown in FIG. FIG. 6 is a schematic cross-sectional view of the optical system. The optical system 23 is housed in a lens barrel 22 isolated from the surrounding atmosphere, and the atmosphere is shut off on the optical path by a parallel plate seal glass 24. The inside is a gas supply port 25 and an exhaust port 26, and the inside is purged with a clean gas. A gas supply port 27 is provided on one side and an exhaust port 28 is provided on the opposite side to allow a clean gas to flow on the surface of the seal glass 24 in contact with the surrounding atmosphere. The flow rate and pressure are adjusted so that the gas flows on the surface of the sealing glass.
As described above, the first and second embodiments can be applied to an optical system other than the projection system. Further, the present invention can be applied not only to the exposure apparatus but also to other optical systems using ultraviolet rays.

It is a schematic diagram of Example 1 in the present invention, (a) is a schematic sectional view of a projection lens barrel to which the present embodiment is applied, and (b) is a schematic diagram of a lower surface. FIG. 9 shows another configuration example of the first embodiment of the present invention. FIG. 4 is a schematic view of a second embodiment of the present invention. FIG. 9 is a schematic view of a third embodiment of the present invention. FIG. 14 is a schematic view of another application form of the third embodiment of the present invention.

Explanation of reference numerals

1: Projection optical system lens barrel of semiconductor exposure apparatus 2: Projection optical system optical element 3: Lowest lens closest to wafer among optical elements 4: Purge gas supply port in lens barrel 5: Gas flow rate adjustment Valve 6: Purge gas outlet in lens barrel 7: Gas flow control valve 8: Wafer 9: Wafer stage 10: Atmosphere outside lens barrel, ie, atmosphere in exposure apparatus chamber 11: Atmosphere in purged lens barrel 12: Gas flow between the wafer and the lens barrel 13: Gas supply port 14: Flow control valve 15: Gas flow 16: Cover 17: Exhaust port 18, 19: Supply port and gas flow control valve 20 of the third embodiment 20 , 21: Exhaust port and gas flow control valve of Example 3 22: Lens barrel of another optical system of Example 3 23: Optical system 24: Seal glass 2 : Supply port of the barrel in the purge gas 26: outlet 27: sealing glass surface a gas supply port for supplying gas to 28: exhaust port 29, 30: flow control valve 31: gas flow 32: Cover

Claims (17)

Including a plurality of optical elements, a projection optical system for projecting the pattern on the surface to be projected,
A lens barrel that houses the plurality of optical elements,
Of the plurality of optical elements, between the final optical element and the projection surface arranged at an opening position provided at a position closest to the projection surface of the lens barrel at a position closest to the projection surface. Gas supply means arranged to supply gas from one side of the projection optical system,
An exposure apparatus having a gas exhaust unit disposed on a side opposite to the one side and exhausting the gas,
The gas supply means has a plurality of gas supply ports, the gas exhaust means has a plurality of gas exhaust ports,
By supplying gas from the plurality of gas supply ports and exhausting the supplied gas from the plurality of gas exhaust ports with respect to the surface on the projection surface side of the final optical element, An exposure apparatus, wherein a gas is locally supplied to the surface on the projection surface side in a laminar flow. A cover surrounding the optical path of the projection optical system on the projection surface side of the final optical element, wherein the plurality of gas supply ports and the plurality of gas exhaust ports are provided on the cover. The exposure apparatus according to claim 1, wherein: 3. The apparatus according to claim 2, further comprising a chamber gas supply unit that supplies a chamber gas into the lens barrel, wherein the chamber gas and the gas supplied by the gas supply unit are of the same gas type. Exposure equipment. 4. The exposure apparatus according to claim 1, wherein the gas supplied by the gas supply unit is an inert gas. 5. The exposure apparatus according to claim 4, wherein the inert gas is nitrogen or helium. 6. The exposure apparatus according to claim 1, wherein the supply gas is air, and the impurities are removed by the impurity removing unit. 7. 7. The exposure apparatus according to claim 1, further comprising: means for removing impurities contained in a gas locally supplied to the surface of the optical element by the gas supply means. The exposure apparatus according to any one of claims 1 to 7, wherein the gas supplied to the gas supply unit is supplied from a gas supply facility having a unit for removing impurities. 9. The exposure apparatus according to claim 1, further comprising a unit configured to adjust a gas supply flow rate and a pressure from the gas supply unit according to a use state of the exposure apparatus. The exposure apparatus according to any one of claims 1 to 9, further comprising means for adjusting a gas discharge flow rate and a pressure from the gas discharge means according to a use state of the exposure apparatus. 11. The exposure apparatus according to claim 1, wherein the exposure apparatus has a function of adjusting a temperature of a gas supplied from the gas supply unit. The exposure apparatus according to any one of claims 1 to 11, wherein light having a wavelength of ultraviolet light is used. 3. The exposure apparatus according to claim 1, wherein the plurality of gas supply ports and the plurality of gas exhaust ports are respectively arranged in a direction substantially parallel to the projection target surface. 4. The exposure apparatus according to any one of claims 1 to 13, wherein the last optical element is an optical element opposed to a wafer disposed at a position of a projection surface of the projection optical system. Including a plurality of optical elements, a projection optical system for projecting the pattern on the surface to be projected,
A lens barrel that houses the plurality of optical elements,
Of the plurality of optical elements, between the final optical element and the projection surface arranged at an opening position provided at a position closest to the projection surface of the lens barrel at a position closest to the projection surface. Gas supply means arranged to supply gas from one side of the projection optical system,
An exposure apparatus having a gas exhaust unit disposed on a side opposite to the one side and exhausting the gas,
A cover surrounding the optical path of the projection optical system on the projection surface side of the final optical element,
The gas supply means has a plurality of gas supply ports in the cover, the gas exhaust means has a plurality of gas exhaust ports in the cover,
An exposure apparatus, wherein a gas is supplied from the plurality of gas supply ports to a surface of the final optical element on the side of the projection surface, and the supplied gas is exhausted from the plurality of gas exhaust ports. Including a plurality of optical elements, a projection optical system for projecting the pattern on the surface to be projected,
A lens barrel that houses the plurality of optical elements,
The gas is supplied from one side of the side surface of the final optical element arranged at an opening position provided at a position closest to the projection surface of the plurality of optical elements at a position closest to the projection surface of the lens barrel. Gas supply means;
An exposure apparatus having a gas exhaust unit disposed on a side opposite to the one side and exhausting the gas,
A cover surrounding the optical path of the projection optical system on the projection surface side of the final optical element,
The gas supply means has a plurality of gas supply ports in the cover, the gas exhaust means has a plurality of gas exhaust ports in the cover,
An exposure apparatus, wherein a gas is supplied from the plurality of gas supply ports to a surface of the final optical element on the side of the projection surface, and the supplied gas is exhausted from the plurality of gas exhaust ports. 17. A device manufacturing method, comprising: exposing a wafer by the exposure apparatus according to claim 1; and developing the exposed wafer.

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