JPH11162831A - Projection aligner and projection aligning method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance aligning precision and execute pattern transfer by a method, wherein contamination by an emulsion, etc., adhering to an optical member is reduced for a projection optical system. SOLUTION: After an optical member OB at a specified position has been cleaned by a cleaner 8 at a time other than transferring, or while a gas is made to flow between a sensitivity substrate W and the optical member OB at a specified position by a contamination preventing device, a pattern transfer to the sensitivity substrate W is performed. In addition, at a time other than transferring, the optical member OB at a specified position is measured by the contamination preventing device, and the transfer is made, or cleaning or replacing of the optical member OB is executed based on measurement results.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a projection exposure apparatus and a projection exposure method, and more particularly to a projection exposure apparatus used for transfer when a semiconductor element or a liquid crystal display element is manufactured by a photolithography process. And a projection exposure method.

[0002]

2. Description of the Related Art In recent years, in this type of apparatus, in order to improve resolution in response to a demand for further miniaturization of a circuit pattern,
Light in the ultraviolet region having a short wavelength is generally used as illumination light for exposure. Further, since the productivity of the projection exposure apparatus depends on the exposure time, exposure illumination light with high illuminance is used in order to shorten the exposure time in response to a demand for improvement in productivity. Therefore, at the time of transfer, the surface of the substrate such as a wafer or a glass plate on which a photosensitive agent (photoresist) is applied is irradiated with light having a high energy density.

When light having a high energy density is applied to a surface coated with a photosensitive agent, a phenomenon in which the photosensitive agent or a modified product of the photosensitive agent (hereinafter referred to as a photosensitive agent or the like) scatters or vaporizes and evaporates (ablation). Occurs. In this way, a part of the photosensitive agent or the like dissociated from the substrate reaches the optical member located near the substrate and adheres to the substrate facing surface of the optical member.

When the photosensitive agent or the like adheres to the optical member in this way, the adhered substance acts as an optical stain on the optical member. The illuminance at the time of transfer of the photosensitive agent coated surface portion is lower than that of the other portions. That is,
Variations in the exposure amount occur depending on the position of the pattern to be transferred on the photosensitive agent-coated surface. As a result, for example, the line width to be uniform becomes non-uniform, and when the final product is an integrated circuit, it causes a malfunction.

Further, if the attached matter on the optical member has a property of absorbing the illumination light, the attached matter absorbs the illumination light and is heated during the transfer, so that the temperature of the optical member rises and the optical member is heated. Since the characteristics change, the imaging characteristics of the entire projection optical system change.

In order to avoid such a situation, a replaceable cover glass or a polymer film is disposed between an optical member such as a projection optical system and a sensitive substrate, so that a contaminant substance is contaminated on the optical member of the projection optical system. A technique for preventing the arrival has been proposed (Japanese Patent Laid-Open Publication No. 365650 / etc .: hereinafter referred to as a conventional example).

[0007]

In recent years, the projection optical system has tended to increase its numerical aperture (NA) to the limit in order to increase its resolution to its limit. Therefore, the maximum value of the incident angle of the illumination light for exposure incident on the sensitive substrate to the sensitive substrate becomes larger, and in order to reduce the diameter of the optical system of the exposure apparatus, the projection optical system is more sensitive during transfer. It is considered to approach the substrate. Bringing the projection optical system closer to the sensitive substrate during transfer works in a direction that is advantageous for reducing aberrations in optical design.

However, if the projection optical system is moved closer to the sensitive substrate during transfer, the adhesion of a substance causing contamination such as a photosensitive agent dissociated from the sensitive substrate to the optical member of the projection optical system increases. The dirt on the optical member becomes a serious problem. In addition, with the demand for improvement in resolution and productivity, shorter wavelength and higher illuminance of the illumination light for exposure have been developed.
It is becoming a more serious problem.

In the above-mentioned conventional example, a replaceable dirt preventing member is arranged between the projection optical system and the sensitive substrate, so that the transfer between the projection optical system and the exposed surface of the sensitive substrate is performed during transfer. Has a three-layer structure of an atmosphere between the projection optical system and the stain prevention member, a stain prevention member, and an atmosphere between the stain prevention member and the exposed surface of the sensitive substrate. Therefore, there is a limit in bringing the projection optical system closer to the sensitive substrate during transfer.

[0010] In addition, due to the recent demand for higher precision of pattern transfer, the reproducibility of mounting the replaceable stain preventing member has become extremely strict, and the allowable optical variation of the stain preventing member itself has become very severe. Therefore, adopting a cover glass having a certain thickness as a replaceable dirt prevention member has reached its limit. That is,
If the stain prevention member is replaced, the aberration balance of the entire projection optical system must be adjusted, which is not practical.

When a polymer film is used as the replaceable stain prevention member, the problem of re-adjustment of the aberration balance of the projection optical system does not occur because the film thickness is small. For a component having a large incident angle, the transmittance is deteriorated. In particular, S has a large contribution to the imaging.
The transmittance of polarized light deteriorates and affects the imaging performance. In the case of a polymer film, it is difficult to perform an anti-reflection coating, and this is also unsuitable for actual use.

The present invention has been made under such circumstances, and a first object of the projection exposure apparatus of the present invention is to reduce dirt due to the adhesion of a photosensitive agent or the like to an optical member such as a projection optical system. Another object of the present invention is to provide a projection exposure apparatus that improves exposure accuracy.

A second object of the projection exposure apparatus of the present invention is to provide a projection exposure apparatus which improves exposure accuracy by cleaning an optical member such as a projection optical system, especially at the time other than the time of pattern transfer. Is to do.

A third object of the projection exposure apparatus of the present invention is to measure dirt on an optical member such as a projection optical system, especially at times other than the time of pattern transfer, and to clean the optical member according to the measurement result. Another object of the present invention is to provide a projection exposure apparatus capable of improving exposure accuracy by replacing the projection exposure apparatus.

A fourth object of the projection exposure apparatus of the present invention is to provide a projection exposure apparatus which improves exposure accuracy by preventing contamination of optical members such as a projection optical system during pattern transfer. To provide.

Another object of the projection exposure method of the present invention is to provide a projection exposure method capable of transferring a pattern in a state in which an optical member such as a projection optical system is less contaminated by a photosensitive agent or the like.

[0017]

According to a first aspect of the present invention, there is provided a projection exposure apparatus for transferring a pattern formed on a mask (R) onto a sensitive substrate (W) via a projection optical system (PL). , An optical member (OB) arranged at a predetermined position
A cleaning device (8, 40, etc.) for cleaning.

According to the projection exposure apparatus of the first aspect, prior to the transfer, the optical member (O) disposed at a predetermined position near the exposed surface of the sensitive substrate (W) by the previous transfer.
By cleaning the dirt such as the photosensitive agent adhered to the substrate facing surface in B), the dirt on the substrate facing surface of the optical member (OB) at the time of transfer is reduced, so that the exposure accuracy can be improved.

The cleaning may be carried out each time the transfer is performed. However, if the optical member is less contaminated by one transfer, the contaminants may be kept within an allowable range, for example, every predetermined number of transfers or periodically. It is sufficient to execute it.

In the projection exposure apparatus of the first aspect, various arrangements of the cleaning device are conceivable. However, as in the invention of the second aspect, the cleaning device (8, 40, etc.)
Or a cleaning device (8, 40, etc.) different from the stage for holding the sensitive substrate, as in the invention according to claim 4. It may be mounted on a moving mechanism (CST).

According to the projection exposure apparatus of the present invention, the drive of the cleaning member (8) necessary for performing the cleaning is used for moving the sensitive substrate (W) in performing the transfer. Since it can be performed by the stage (WST) holding the sensitive substrate (W) which is mounted as standard,
The cleaning function can be easily realized.

In the projection exposure apparatus according to the second aspect, as in the third aspect, the cleaning device (8) includes the stage (W).
ST), it is preferably mounted on a driving device (12) for vertically moving the sensitive substrate (W).

According to the projection exposure apparatus of the third aspect, the cleaning device (8) and the optical component (O) are driven by the driving device (12).
B) can be brought into contact with or separated from each other.

According to the projection exposure apparatus of the fourth aspect,
Since the cleaning device (40, etc.) is moved to the cleaning position by a moving mechanism (CST) separate from the stage (WST) holding the sensitive substrate (W), the stage (WST) holding the sensitive substrate (W) The cleaning function and the transfer function can be realized while ensuring the accuracy and cleanliness of the cleaning.

In the projection exposure apparatus according to claim 2 or 4,
Although there are various possible configurations of the cleaning device, an ultrasonic cleaning device (40) for immersing a cleaning target portion of the optical member (OB) in a cleaning solution and performing ultrasonic cleaning as in the invention according to claim 5 is provided. It is also possible to provide a cleaning member (8) that comes into contact with the substrate facing surface of the optical member (OB) and cleans the substrate facing surface, as in the invention described in claim 6. And, as in the invention of claim 7,
A solution ejector (72) for spraying a cleaning solution onto the substrate facing surface of the optical member (OB) may be provided.

In the projection exposure apparatus according to the sixth aspect, the cleaning member (8) has a surface to be in contact with the substrate facing surface, and includes a flexible member (34) that does not damage the optical member (OB) at the time of contact. Is preferred. Further, it is possible to further include a driver that drives the cleaning member in a state where the flexible member (34) is in contact with the substrate facing surface, and rubs the flexible member against the substrate facing surface. Moreover, it is possible to use a porous member capable of infiltrating the cleaning solvent as the flexible member (34).

[0027] In the projection exposure apparatus of claim 7, it is preferable to employ, as the solution ejector (72), an ejector that ejects a cleaning solution to which ultrasonic vibration is applied.

According to an eighth aspect of the present invention, there is provided a projection exposure apparatus for transferring a pattern formed on a mask (R) onto a sensitive substrate (W) via a projection optical system (PL). A dirt measuring device (84) for measuring dirt on the optical member (OB) is provided.

The dirt measuring device (84) includes a cleaning device (8,
36 etc.) or may be provided alone.

The dirt measuring device (84) is connected to the cleaning device (8, 3).
6)), before the transfer is performed,
By measuring the dirt on the optical member (OB), it is possible to determine whether or not the optical member (OB) needs to be cleaned. Therefore, based on the result of the measurement by the dirt measuring device (84), when the cleaning of the optical member (OB) is required, the cleaning can be surely performed, and the effect of the cleaning can be confirmed, so that the exposure accuracy can be improved. Can be.

In the case where the dirt measuring device (84) is provided alone, the optical member (OB) is required before the transfer is performed.
By measuring the dirt, it is possible to determine whether or not the optical member (OB) needs to be replaced. Therefore,
From the result of the measurement by the dirt measuring device (84), when the replacement of the optical member (OB) is required, the replacement can be reliably performed, so that the exposure accuracy can be improved.

Here, various configurations of the dirt measuring device (84) are conceivable. For example, as in the ninth aspect of the present invention, the dirt measuring device (84) irradiates light to the optical member (OB). Irradiation optical systems (86, 88, and 90); a light detector (94) for detecting light from the optical member (OB);
Based on the detection result of the photodetector (94), the optical member (O
And a dirt measurement processor (96) for measuring dirt in B).

It is also possible to use illumination light for exposure as measurement light for measurement. In this case, however, it is necessary to select a member that transmits ultraviolet light as an optical member constituting an optical system for measurement. Therefore, there is less room for selecting an optical member. Then, the dirt measuring device (84) uses the sensitive substrate (W)
It is preferable to irradiate the measurement light to the optical member (OB) from the side, and to detect the reflected component light of the measurement light reflected by the optical member (OB).

According to a tenth aspect of the present invention, a mask (R)
A projection exposure apparatus for transferring a pattern formed on a sensitive substrate (W) via a projection optical system (PL), wherein the optical member is disposed near a surface to be exposed of the sensitive substrate (W). (9) A dirt prevention device (9) for flowing gas between the (OB) and the sensitive substrate (W) to prevent foreign matter generated from the sensitive substrate (W) from reaching the optical member (OB).
8) is provided.

According to the projection exposure apparatus of the tenth aspect, the anti-smudge device (98) includes the sensitive substrate (W) and the optical member (O).
A gas is caused to flow between B and B) to prevent the contamination-causing substance from reaching the sensitive substrate (W). Therefore, no inclusion other than gas is required in the traveling path of the exposure illumination light between the optical member (OB) and the sensitive substrate (W). Therefore, dirt on the substrate facing surface of the optical member (OB) is reduced, and the exposure accuracy can be improved.

Here, various configurations of the dirt prevention device (98) are conceivable. For example, a gas flow path is set near the substrate facing surface of the optical member (OB) as in the eleventh aspect of the present invention. Flow path setting members (102a and 104)
a) and a gas supply device (106) for supplying gas to the flow path set by the flow path setting members (102a and 104a).

The optical member according to the first to eleventh aspects of the present invention can be variously conceived. However, as in the twelfth aspect of the present invention, the optical member is located on the optical path of the illumination light for exposure, and The optical member may be the closest optical member, or may be the optical member at the tip of an optical system for positioning the sensitive substrate, as in the invention according to claim 13. .

Here, the optical system for aligning the sensitive substrate includes an alignment optical system for aligning the sensitive substrate in a direction perpendicular to the optical axis of the projection optical system and a direction parallel to the optical axis of the projection optical system. There is a focus detection optical system that positions the sensitive substrate.

According to the projection exposure apparatus of the twelfth aspect, the projection optical system arranged on the optical path of the illumination light for exposure and closest to the sensitive substrate due to the adhesion of the stain-causing substance at the time of transfer. There is no need to worry about contamination of the optical member, and it is possible to design a projection optical system in which the projection optical system is close to the sensitive substrate, so that a projection optical system with a higher numerical aperture can be easily realized.

Further, according to the projection exposure apparatus of the thirteenth aspect, the optical member at the tip of the optical system for positioning the sensitive substrate to which the photosensitive agent or the like easily adheres is cleaned, and the dirt measurement is performed.
Alternatively, since the contamination is prevented, the contamination of the optical member is reduced, and the exposure accuracy can be improved.

According to a fourteenth aspect of the present invention, the mask (R)
Is a projection exposure method for transferring a pattern formed on a photosensitive substrate (W) via a projection optical system (PL), wherein a cleaning step for cleaning dirt on an optical member (OB) disposed at a predetermined position is provided. And a transfer step of transferring the pattern formed on the mask (R) to the sensitive substrate (W) via the projection optical system (PL) after cleaning the optical member (OB).

The optical member according to the fourteenth aspect of the present invention can be variously conceived. However, as in the invention according to the fifteenth aspect, the optical member is on the optical path of the illumination light for exposure and is closest to the sensitive substrate. The optical member may be arranged at

According to the projection exposure method of the present invention, first, the cleaning step is performed, and the optical member (OB) disposed at a predetermined position near the exposed surface of the sensitive substrate (W) by the previous transfer. The optical member (OB) is cleaned by cleaning the dirt such as the photosensitive agent adhered to the optical member. Thereafter, by performing a transfer step, the projection optical system (OB) can be cleaned in a state where there is little contamination of the optical member (OB) and there is no inclusion other than the atmosphere between the projection optical system (PL) and the sensitive substrate (W). (PL)
And the sensitive substrate (W) are brought close to each other to perform suitable transfer.

The cleaning may be performed each time the transfer is performed. However, as long as the optical member (OB) is less contaminated by one transfer, the cleaning step may be performed in the cleaning step. The relationship between the contamination on the substrate facing surface of the optical member (OB) and the number of times of transfer, which is performed in advance, is measured, and the optical member (O
B) The method further includes a dirt evaluation step of evaluating the limit number of times of transfer, which is the number of exposures until the substrate facing surface reaches a predetermined unacceptable dirt from a clean state, and the transfer after execution of the previous cleaning step. The cleaning step may be performed before the number of times reaches the limit number of times of transfer.

According to the projection exposure method of the sixteenth aspect, since the cleaning process may be performed while the contamination is within the allowable range, for example, at every predetermined number of transfers or periodically, the productivity is improved.

According to a seventeenth aspect of the present invention, the mask (R)
Is a projection exposure method for transferring a pattern formed on a photosensitive substrate (W) via a projection optical system (PL), wherein dirt is measured on an optical member (OB) disposed at a predetermined position. And a judging step of judging whether or not to execute transfer based on the measurement result obtained in the measuring step.

According to the projection exposure method of the seventeenth aspect, prior to the execution of the transfer, first, a dirt measuring step is performed,
The contamination of the optical member (OB) is measured. Then, in the determination step, it is determined whether or not the contamination of the optical member (OB) is expected to exceed a predetermined allowable limit value by the transfer from the measurement result in the contamination measurement step to the execution of the next contamination measurement step. Make a decision. If the contamination of the optical member (OB) is expected to exceed a predetermined allowable limit, the optical member (OB) is cleaned or replaced. If the contamination of the optical member (OB) is not expected to exceed a predetermined allowable limit, the transfer is executed.

Therefore, based on the result of the measurement in the dirt measuring step, when the cleaning or replacement of the optical member (OB) is required, the cleaning or replacement can be executed reliably, so that the exposure accuracy is improved and the productivity is improved. can do.

[0049]

DESCRIPTION OF THE PREFERRED EMBODIMENTS << First Embodiment >> A projection exposure apparatus and a projection exposure method according to a first embodiment of the present invention will now be described with reference to FIG.
This will be described with reference to FIG.

The projection exposure apparatus according to the present embodiment transfers a pattern onto the wafer W, and cleans an optical member disposed near the wafer W during the transfer except during the transfer. FIG. 1 shows a schematic configuration of a projection exposure apparatus of the present embodiment. The projection exposure apparatus of the present embodiment is a projection exposure apparatus of a so-called step-and-scan exposure system.

As shown in FIG. 1, the projection exposure apparatus of this embodiment comprises a light source 1 and an illumination optical system (2, 3, 5-7).
, A reticle stage RST as a mask stage for holding a reticle R as a mask, a projection optical system PL, a wafer W as a substrate, or a wafer as a stage for holding one of the cleaning members 8 as a cleaning device A stage device 10 having a stage WST and a control system for these components are provided. Then, during transfer, wafer W is held on wafer stage WST, and during cleaning, cleaning member 8 is held on wafer stage WST.

The illumination system includes a light source 1, a collimator lens, a fly-eye lens, etc. (all not shown), an illuminance uniforming optical system 2, a relay lens 3, a variable ND filter 4, a reticle blind 5, a relay lens 6. And dichroic mirror 7 (including illuminance uniforming optical system 2, relay lens 3, reticle blind 5, relay lens 6)
And the dichroic mirror 7 constitutes an illumination optical system).

Here, each component of the illumination system will be described together with its operation. Illumination light I generated by the light source 1 will be described.
After passing through a shutter (not shown), the light L is converted by the illuminance uniforming optical system 2 into a light beam having a substantially uniform illuminance distribution. As the illumination light IL, for example, KrF excimer laser light or A
An excimer laser beam such as an rF excimer laser beam, a harmonic of a copper vapor laser or a YAG laser, or an ultraviolet bright line (g line, i line, or the like) from an ultrahigh pressure mercury lamp is used.

The light beam emitted horizontally from the illumination uniforming optical system 2 reaches the reticle blind 5 via the relay lens 3. The reticle blind 5 is a reticle R
The variable ND filter 4 is provided so as to be in close contact with the reticle blind 5 on the side of the relay lens 3, which is disposed on a surface optically conjugate with the pattern forming surface of the wafer W and the exposure surface of the wafer W.

As the reticle blind 5, a plurality of movable light shielding plates (for example, two L-shaped movable light shielding plates) are opened and closed by, for example, a motor to adjust the size of the opening (slit width or the like). Things are used. By adjusting the size of the opening, the slit-shaped illumination area IAR (see FIG. 2) for illuminating the reticle R can be set to an arbitrary shape and size.

The variable ND filter 4 sets the transmittance distribution to a desired state. For example, the variable ND filter 4 has a double blind structure,
It is composed of a liquid crystal display panel, an electrochromic device, or an ND filter having a desired shape. In the present embodiment, the variable ND filter 4 is controlled by the variable ND filter control unit 22 such as taking in and out (or its rotation angle), whereby the illuminance distribution in the illumination area IAR on the reticle R is intentionally adjusted. Therefore, the exposure amount on the wafer W during scanning can be kept constant. Normally, the entire variable ND filter 4 is 100% transparent, and the reticle R
The illuminance distribution in the upper illumination area IAR is uniform.

The light beam that has passed through the variable ND filter 4 and the reticle blind 5 passes through the relay lens 6 and reaches the dichroic mirror 7, where it is bent vertically downward and the illumination area of the reticle R on which a circuit pattern or the like is drawn. Illuminate the IAR part.

A reticle R is fixed on the reticle stage RST by, for example, vacuum suction. The reticle stage RST is used to position an optical axis IX of an illumination optical system (optical axis A of a projection optical system PL described later) for positioning the reticle R.
It is configured to be capable of minutely driving two-dimensionally (in the X-axis direction, in the Y-axis direction orthogonal to the X-axis direction, and in the rotation direction around the Z-axis orthogonal to the XY plane) in a plane perpendicular to the X-axis.

The reticle stage RST is a reticle driving section (not shown) composed of a linear motor or the like.
Thereby, it is possible to move at a specified scanning speed in a predetermined direction (scanning direction). This reticle stage RST
Means that the entire surface of the reticle R has at least the optical axis I of the illumination optical system.
It has a travel stroke that can cross X.

At the end of reticle stage RST, a reticle laser interferometer (hereinafter, referred to as “reticle interferometer”) 1
A movable mirror 15 for reflecting the laser beam from the reticle stage 6 is fixed.
It is always detected with a resolution of about m. Where, in practice,
On the reticle stage RST, a moving mirror having a reflecting surface perpendicular to the scanning direction and a moving mirror having a reflecting surface perpendicular to the non-scanning direction are provided. In correspondence with this, a reticle interferometer is also provided for measuring the position in the scanning direction. Although an interferometer and an interferometer for measuring the position in the non-scanning direction are provided, these are typically shown as a movable mirror 15 and a reticle interferometer 16 in FIG.

The position information RP of the reticle stage RST from the reticle interferometer 16 is sent to the stage control system 19. The stage control system 19 outputs a reticle drive instruction MR (not shown) based on the position information of the reticle stage RST, and drives the reticle stage RST via the reticle drive.

Since the initial position of the reticle stage RST is determined so that the reticle R is accurately positioned at a predetermined reference position by a reticle alignment system (not shown), the position of the movable mirror 15 is changed by the reticle interferometer 16. This means that the position of the reticle R has been measured with sufficiently high accuracy.

The projection optical system PL is disposed below the reticle stage RST in FIG. 1 and its optical axis AX
The direction of (corresponding to the optical axis IX of the illumination optical system) is the Z-axis direction, and an objective lens OB is provided as an optical member closest to the wafer W during transfer. Projection optical system PL
Uses a refracting optical system having a predetermined reduction magnification (for example, 1/5 or 1/4) that is telecentric on both sides. Therefore, when the illumination area IAR of the reticle R is illuminated by the illumination light IL from the illumination optical system, the illumination light IL that has passed through the reticle R causes the reduced image of the circuit pattern of the reticle R via the projection optical system PL. Is formed on the wafer W having a surface coated with a photoresist (photosensitive agent).

The stage device 10 is disposed below the projection optical system PL in FIG. 1, and moves on the base BS in the XY two-dimensional directions in a substantially square wafer stage WST.
It has a wafer holder 9 mounted on wafer stage WST and a center-up 12 (see FIG. 3) as a vertically moving member incorporated inside wafer holder 9.

The wafer W is vacuum-sucked on the wafer holder 9. The wafer holder 9 can be tilted in any direction with respect to the best imaging plane of the projection optical system PL, and
Is finely movable in the optical axis AX direction (Z direction). Further, the wafer holder 9 can also rotate around the optical axis AX.

The wafer stage WST moves not only in the scanning direction (X direction), but also in a direction perpendicular to the scanning direction so that a plurality of shot areas on the wafer W can be positioned in an exposure area conjugate with the illumination area IAR. Direction (Y direction)
It performs a step-and-scan operation in which the operation of scanning (scanning) each shot area on the wafer W and the operation of moving to the exposure start position of the next shot are repeated. This wafer stage WST is controlled by a wafer stage driving unit 24 such as a motor to rotate X.
It is driven in the Y two-dimensional direction.

A movable mirror 17 for reflecting a laser beam from a wafer laser interferometer (hereinafter, referred to as a “wafer interferometer”) 18 is fixed to an end of wafer stage WST, and the position of wafer stage WST in the XY plane is determined. It is always detected by the wafer interferometer 18 with a resolution of, for example, about 0.01 μm. Here, actually, the wafer stage W
On ST, there are provided an X moving mirror 17X having a reflecting surface orthogonal to the scanning direction and a Y moving mirror 17Y having a reflecting surface orthogonal to the non-scanning direction. Although an X interferometer 18X for position measurement and a Y interferometer 18Y for position measurement in the Y-axis direction are provided, these are typically shown as a moving mirror 17 and a wafer interferometer 18 in FIG. The position information (or speed information) SP1 of the wafer stage WST is sent to the stage control system 19, and the stage control system 19 outputs a wafer stage drive instruction MS1 based on the position information (or speed information). 24 controls wafer stage WST.

Here, a circular holder is used as the wafer holder 9, and a concentric suction groove (not shown) for vacuum suction of the wafer W is provided on the upper surface thereof.
The inside of these suction grooves is evacuated by the vacuum suction force of a vacuum pump (vacuum pump) (not shown) so that the wafer W is sucked. In order to effectively use the depth of focus of the projection optical system PL, the wafer W needs to be held with good flatness, and there is a possibility that dust and the like may be interposed.
It is designed to keep the contact area as small as possible and to keep it from bending. Note that, in addition to the concentric circular grooves, a type in which point-like grooves are distributed, a linear groove, and the like are devised, and it is a matter of course that any type of the concave grooves may be provided.

As shown in the sectional view of FIG. 3, the center-up 12 has a suction portion 12a and a shaft portion 12b provided on the uppermost surface, and is driven by a center-up driving mechanism (not shown) in the unit 30. The suction unit 12a is moved up and down in response to a center-up driving instruction MC1 output from the stage control system 19. A suction hole (not shown) is formed at the center of the suction portion 12a.
Is connected to a suction tube connected to a vacuum pump (not shown) near the bottom of the unit 30 through the center of the unit 30 in the axial direction. Thus, the wafer W can be sucked on the upper surface of the suction portion 12a by the vacuum suction force of a vacuum pump (not shown). The vertical movement of the center-up 12 is monitored by a limit switch, a position sensor, and the like (not shown).

In the projection exposure apparatus of this embodiment, as shown in FIG. 2, the scanning direction (X direction) of the reticle R
The reticle R is illuminated with illumination area IAR rectangular (slit shape) having a longitudinal direction perpendicular to the reticle R is scanned at a speed V _R in the -X direction at the time of transfer (scan). The illumination area IAR (the center substantially coincides with the optical axis AX) is projected onto the wafer W via the projection optical system PL,
A slit-shaped exposure area IA is formed. Since the wafer W is to the reticle R in inverted imaging relationship, the wafer W is the direction of the velocity V _R is scanned at a speed V _W in synchronization with the reticle R in the opposite direction (+ X direction), the shot on the wafer W The entire surface of the area SA can be exposed. Scanning speed ratio V _W
/ V _R is made to that corresponding to the reduction magnification of the exact projection optical system PL, the pattern of the pattern area PA of the reticle R is accurately reduced and transferred onto the shot area SA on the wafer W. The width of the illumination area IAR in the longitudinal direction is the reticle R
It is set so as to be wider than the upper pattern area PA and narrower than the maximum width of the light-shielding area ST, and the entire pattern area PA is illuminated by scanning.

Returning to FIG. 1, on the side of the projection optical system PL,
An off-line for detecting the position of an alignment mark (wafer mark) attached to each shot area on the wafer W
An Axis type alignment microscope (not shown, which will be described later) is provided, and the measurement result of the alignment microscope is supplied to a main controller 20 that controls the operation of the entire apparatus. From the measured positions of the marks, the array coordinates of the shot area on the wafer W are calculated by a statistical calculation method using the least square method as disclosed in, for example, Japanese Patent Application Laid-Open No. 61-44429.

The above-mentioned alignment microscope (not shown) is fixed to one side surface of the projection optical system PL. In this embodiment, a high-magnification image processing system is used. The alignment microscope includes a light source that emits broadband illumination light such as a halogen lamp, an objective lens, an index plate, an image sensor such as a CCD, a signal processing circuit, and an arithmetic circuit (all not shown). Illumination light emitted from a light source constituting the alignment microscope passes through an objective lens inside the alignment microscope, and is irradiated onto the wafer W. Light reflected from a wafer mark area (not shown) on the surface of the wafer W is reflected inside the alignment microscope. Then, the image of the wafer mark and the image of the index on the index plate are formed on an imaging surface such as a CCD through the objective lens and the index plate sequentially. The photoelectric conversion signals of these images are processed by the signal processing circuit, and the arithmetic circuit calculates the relative position between the wafer mark and the index. The calculation result is supplied to main controller 20. Although various methods of aligning the wafer W have been proposed, other methods can be similarly used.

The apparatus shown in FIG. 1 supplies an image forming light beam for forming a pinhole or a slit image toward the best image forming plane of the projection optical system PL obliquely with respect to the optical axis AX direction. An oblique incidence type wafer position detection system (focus detection system), which includes an irradiation optical system 13 for receiving light and a light receiving optical system 14 for receiving, via a slit, a light beam reflected by the surface of the wafer W of the image forming light beam, It is fixed to a support (not shown) that supports the projection optical system PL. The configuration of the wafer position detection system is described in, for example, Japanese Patent Application Laid-Open No. 60-168112.
In the above publication, a positional deviation in the vertical direction (Z direction) of the wafer surface with respect to the imaging plane is detected, and the wafer holder 9 is moved in the Z direction so that the wafer W and the projection optical system PL are kept at a predetermined distance. Used to drive. The wafer position information from the wafer position detection system is sent to the stage control system 19 via the main controller 20. The stage control system 19 drives the wafer holder 9 in the Z direction based on the wafer position information.

In the present embodiment, the angle of a parallel flat glass (not shown) provided beforehand in the light receiving optical system 14 is adjusted so that the image plane becomes the zero point reference, and the wafer position is detected. System calibration shall be performed. Further, for example, Japanese Patent Laid-Open No. 58-11370
The wafer position detection system is configured to use a horizontal position detection system as disclosed in Japanese Patent Application Laid-Open No. 6-206, or to detect a focus position at a plurality of arbitrary positions in an image field of the projection optical system PL ( For example, by forming a plurality of slit images in the image field), the inclination of the predetermined area on the wafer W with respect to the image plane may be detected.

FIG. 4 shows the structure of cleaning member 8 mounted on wafer stage WST instead of wafer W during cleaning. FIG. 4A is a perspective view of the cleaning member 8, and FIG. 4B is a vertical sectional view of the cleaning member 8 taken along the line A-A. As shown in FIG. 4, the cleaning member 8 includes a base member 32 made of a hard material such as a metal, and a flexible member 34 adhered and fixed to the upper bottom surface of the base member 32. The flexible member 34 is made of a material that does not damage the objective lens OB when it comes into contact with the objective lens OB. For example, a cloth-like, paper-like, or sponge-like member can be suitably used.

The cleaning member 8 is placed on the suction portion 12a such that the contact portion of the center up 12 with the suction portion 12a is located at the center of the lower bottom surface of the cleaning member 8, and is vacuum-sucked. Then, the cleaning member 8 moves up and down by moving the center up 12 up and down in a state of being vacuum-sucked.

In the projection exposure apparatus of the present embodiment, pattern transfer is performed as follows.

First, prior to transferring the pattern to the wafer W, the exposed substrate facing surface of the objective lens OB of the projection optical system PL is cleaned. FIG. 5 shows a cleaning operation of the objective lens OB in the present embodiment. FIG.
Here, in order to clarify the explanation, the vicinity of the objective lens OB of the projection optical system PL and the cleaning member 8 are shown in cross section.

In cleaning, first, the cleaning member 8 is placed on the center-up 12 such that the suction portion 12a of the center-up 12 is substantially at the center of the lower bottom surface of the cleaning member 8 in a state where the wafer W is not mounted. Place. Then, the cleaning member 8 is fixed on the suction portion 12a by vacuum suction.

Here, the mounting of the cleaning member 8 on the center up 12 can be performed manually on the wafer stage WST retracted from below the projection optical system PL, or a wafer transfer device (not shown). Alternatively, the cleaning member 8 may be transferred instead of the wafer W, and the cleaning member 8 may be handled in the same manner as the wafer W.

Next, in response to a command from main controller 20, stage control system 19 confirms the position of wafer stage WST based on position information (or speed information) SP1 of wafer stage WST, and issues wafer stage drive instruction MS.
1 is output, and the wafer stage WST is moved in the XY directions via the wafer stage drive unit 24 to move the cleaning member 8 below the projection optical system PL. Subsequently, the stage control system 19 outputs the center-up drive instruction MC1, raises the suction unit 12a, and brings the flexible member 34 of the cleaning member 8 into contact with the exposed substrate facing surface of the objective lens OB (FIG. )reference).

Then, in response to a command from main controller 20, stage control system 19 confirms the position of wafer stage WST based on position information (or speed information) SP1 of wafer stage WST, and issues wafer stage drive instruction MS.
1, the wafer stage WST is reciprocated in at least one of the X direction and the Y direction via the wafer stage driving unit 24, and the flexible member 34 and the objective lens O are moved.
B is rubbed against the substrate facing surface (see FIG. 5B). Thus, the dirt attached to the substrate facing surface of the objective lens OB is cleaned. In FIG. 5B, only the reciprocating motion of wafer stage WST in the X direction is indicated by arrow X.
It is indicated by 1.

Next, in response to a command from the main controller 20, the stage control system 19 outputs a center-up drive instruction MC1, lowers the suction section 12a, and connects the flexible member 34 of the cleaning member 8 with the objective lens OB. Is separated. Subsequently, the vacuum suction of the cleaning member 8 to the suction portion 12a of the center up 12 is released, and the cleaning member 8 is removed from the wafer stage WST.

Here, removal of cleaning member 8 from wafer stage WST can be manually performed after wafer stage WST is retracted from below projection optical system PL, and wafer transfer is performed similarly to the case of wafer W. It is also possible to carry out in cooperation with the device.

As described above, after the cleaning operation is completed, the pattern transfer to the wafer W is executed.

First, wafer W carried by the wafer carrying device is placed on wafer stage WST and is vacuum-sucked to wafer holder 9. Next, the projection optical system PL
Of the wafer W and the reticle R with respect to are set with high accuracy by the alignment microscope and the stage control system 19. Next, the reticle R is illuminated with exposure illumination light generated by the illumination system (1, 2, 3, 4 to 7), and the pattern drawn on the reticle R is projected onto the wafer W by the projection optical system PL. The pattern is transferred by exposing W.

According to this embodiment, prior to the pattern transfer, the substrate facing surface of the optical member (objective lens OB) of the projection optical system PL disposed closest to the surface to be exposed of the wafer W by the previous transfer. By cleaning the dirt such as the photosensitive agent adhered to the substrate, the dirt on the substrate facing surface of the optical member is reduced, and the projection optical system PL is removed in a state where there is no inclusion other than the atmosphere between the projection optical system PL and the wafer W. And the wafer W are brought close to each other, and suitable transfer can be executed.

The cleaning may be performed each time transfer is performed. However, as long as the optical member is less contaminated by one transfer, the contaminants are kept within an allowable range, for example, each time the transfer is performed a predetermined number of times or periodically. It is sufficient to execute it.

For this purpose, it is necessary to measure the relationship between dirt and the number of transfers, and to evaluate the limit number of transfers, which is the number of exposures until the clean substrate-facing surface reaches a predetermined unacceptable level of dirt. Since the reticle transmittance is also involved in the evaluation of the limit transfer count, the light energy transmitted through the projection optical system PL is measured by a sensor provided on the substrate stage WST, and the measurement result is used as the limit transfer count. It may be reflected in the evaluation. Then, cleaning is performed before the number of times of transfer since the last time cleaning is performed reaches the above-mentioned limit number of times of transfer. As a result, while the contamination is within the allowable range, the cleaning process may be performed, for example, every predetermined number of times of transfer or irradiation with a predetermined amount of light energy, or periodically, so that the projection exposure apparatus is frequently stopped for cleaning. It is not necessary to do so, and productivity is improved.

In this embodiment, the flexible member 3 of the cleaning member 8
4 and the objective lens OB were rubbed against each other to mechanically clean the dirt. However, a porous member was adopted as the flexible member 8, and a cleaning solution containing a solvent for a photosensitive agent was infiltrated into the flexible member 8. Rubs the objective lens OB. It is an essential condition that the cleaning solution does not damage the objective lens OB or its coat.
In this case, the cleaning solution dissolves the stain-causing substance, so that the cleaning efficiency is improved. When a cleaning solution is used, a sufficient cleaning effect may be achieved only by bringing the flexible member 8 into contact with the objective lens OB. In such a case, the rubbing between the flexible member 34 and the objective lens OB can be omitted. Note that the cleaning member 8 can be configured in a wiper shape or a brush shape.

Further, a rotary drive unit for rotating the suction unit 12a constituting the center-up 12 in the XY plane is further provided, and by rotating the suction unit 12a by this rotary drive unit, the cleaning member 8 is rotated to flexibly rotate. The member 34 and the substrate facing surface of the objective lens OB can be rubbed against each other.

<< Second Embodiment >> Hereinafter, a projection exposure apparatus and a projection exposure method according to a second embodiment of the present invention will be described with reference to FIGS.
It will be described based on. In the description of the present embodiment, the same reference numerals are given to the same elements as the elements in the above description, and the overlapping description will be omitted.

The projection exposure apparatus of the present embodiment is different from the projection exposure apparatus of the first embodiment in that the wafer stage WS
Instead of the cleaning member 8 installed on the T, an ultrasonic cleaning device 40 as a cleaning device whose schematic configuration is shown in FIG. 6 is mounted on a cleaning stage CST different from the wafer stage WST. Have. Then, the objective lens OB constituting the projection optical system PL other than at the time of pattern transfer
Is cleaned using an ultrasonic cleaner 40.

As shown in FIG. 6, the ultrasonic cleaner 40
Is mounted on the base BS together with the stage device 10, and is mounted on a substantially square cleaning stage CST that moves in the XY two-dimensional directions on the base BS. Inside the cleaning stage CST, an elevator 38 as a vertical movement mechanism is incorporated.

The cleaning stage CST has the same configuration as the wafer stage WST, and is driven in the XY two-dimensional directions by a cleaning stage driving unit 58 such as a motor.

At the end of the cleaning stage CST, similarly to the wafer stage WST, a cleaning device laser interferometer (hereinafter, referred to as “Wave stage”) is used.
A movable mirror 54 that reflects the laser beam from the “cleaner interferometer” 56 is fixed, and the position of the cleaning stage CST in the XY plane is always detected by the cleaner interferometer 56. Here, actually, the cleaning stage C
On the ST, there are provided an X moving mirror having a reflecting surface orthogonal to the X direction and a Y moving mirror having a reflecting surface orthogonal to the Y direction, and correspondingly, the cleaner interferometer also measures the position in the X axis direction. 6 and a Y-interferometer for measuring the position in the Y-axis direction, these are typically shown as a moving mirror 54 and a cleaner interferometer 56 in FIG. Cleaning stage C
The position information (or speed information) SP2 of ST is sent to the stage control system 19, and the stage control system 19 drives the cleaning stage while checking the position of the cleaning stage CST based on the position information (or speed information). The instruction MS2 is output, and the cleaning stage CST is controlled via the cleaning stage driving unit 58.

The elevator 38 has a structure similar to that of the center up 12 described above. That is, the elevator 38 has a suction portion 38a and a shaft 38b provided on the uppermost surface, and responds to an elevation drive instruction MC2 output from the stage control system 19 by an elevation drive mechanism (not shown) in the unit 52. Suction part 3
8a is moved up and down. Then, similarly to the center up 12, the ultrasonic cleaner 40 can be sucked on the upper surface of the suction part 38a by the vacuum suction force of a vacuum pump (not shown). The vertical movement of the elevator 38 is monitored by a limit switch (not shown), a position sensor, and the like.

[0098] As shown in FIG.
Is provided with a container 44 for accommodating the cleaning solution 42, and is ultrasonically oscillated according to the ultrasonic vibration instruction SS 1 output from the main controller 20, so that the ultrasonic vibration is applied to the cleaning solution 42. And an ultrasonic vibrator 46 for providing Here, as the cleaning solution, high-purity water, acetone, or a solution containing a solvent for a photosensitive agent can be suitably used, but it is essential that the objective lens OB and its coat are not damaged. is there.

In the projection exposure apparatus of the present embodiment, pattern transfer is performed as follows.

First, prior to the transfer of the pattern to the wafer W, the exposed substrate facing surface of the objective lens OB of the projection optical system PL is cleaned. FIG. 7 shows a process of cleaning the objective lens OB in the present embodiment. In FIG. 7, as in FIG. 5, the projection optical system P
The cross section of the vicinity of the L objective lens OB and the ultrasonic cleaner 40 is shown.

In cleaning, first, in response to a command from main controller 20, stage control system 19 causes wafer stage WST to project projection optical system P through wafer stage drive unit 24.
Retreat from below L. Continue with cleaning stage C
The cleaning stage drive unit 58 outputs the cleaning stage drive instruction MS2 while confirming the position of the cleaning stage CST based on the position information (or speed information) SP2 of the ST.
, The cleaning stage CST is moved in the XY directions, and the ultrasonic cleaner 40 is moved below the projection optical system PL. Thereafter, the stage control system 19 issues the elevator drive instruction M
C2 is output, the elevator 38 is raised, and the objective lens O
The exposed substrate facing surface of B is immersed in the cleaning solution 42 (FIG. 7).
(A)).

Next, main controller 20 issues ultrasonic vibration instruction S
S <b> 1 is output, and the ultrasonic vibrator 46 that receives this outputs ultrasonic vibration. This ultrasonic vibration is applied to the cleaning solution 42, and the objective lens O
The substrate facing surface B is cleaned (see FIG. 7B).

Next, main controller 20 controls ultrasonic vibrator 4
After stopping the ultrasonic vibration of the stage 6, the stage control system 19
Outputs the elevation drive instruction MC2, lowers the elevator 38, and separates the ultrasonic vibrator 40 from the projection optical system PL.

After the cleaning operation is completed as described above, the stage control system 19 retreats the cleaning stage CST from below the projection optical system PL via the cleaning stage driving unit 58. Then, similarly to the first embodiment, the wafer W
Is held by the wafer holder 9 and the alignment is performed. Then, the reticle R is illuminated with the exposure illumination light generated by the illumination system, and the pattern drawn on the reticle R is projected onto the wafer W by the projection optical system PL. The wafer W is exposed.

According to this embodiment, as in the first embodiment, prior to the pattern transfer,
By cleaning dirt such as a photosensitive agent adhered to the substrate facing surface of the optical member (objective lens OB) of the projection optical system PL arranged closest to the surface to be exposed of the wafer W, the surface of the optical member facing the substrate is cleaned. Less contamination, projection optical system PL and wafer W
In this state, the projection optical system PL and the wafer W are brought close to each other in a state where there is no intervening matter other than the atmosphere, and suitable transfer can be performed.

Further, in the present embodiment, since the cleaning and the handling of the wafer W are performed using independent drive units, the accuracy and cleanliness of the wafer stage WST are ensured, and the cleaning and exposure can be suitably performed. It can be carried out.

As in the first embodiment, the relationship between dirt and the number of transfers and the amount of light energy applied to the wafer W is measured, and the exposure is performed until the clean substrate-facing surface reaches a predetermined unacceptable level. The projection exposure apparatus can be cleaned by performing the cleaning operation periodically, for example, each time a predetermined number of transfers or irradiation of a predetermined amount of light energy is performed or by evaluating the limit number of times of transfer, which is the number of times. For this reason, it is not necessary to stop frequently, so that the productivity is improved.

<< Third Embodiment >> Hereinafter, a projection exposure apparatus and a projection exposure method according to a third embodiment of the present invention will be described with reference to FIGS.
It will be described based on. In the description of the present embodiment, the same reference numerals are given to the same elements as the elements in the above description, and the overlapping description will be omitted.

The projection exposure apparatus according to the present embodiment is similar to the projection exposure apparatus according to the first embodiment shown in FIG.
Is set on a cleaning stage CST different from wafer stage WST, as shown in FIG. Then, the objective lens OB constituting the projection optical system PL is cleaned using the cleaning member 8 at times other than the time of transfer. That is, in the present embodiment, the ultrasonic cleaner 40 in the second embodiment is replaced with the cleaning member 8 in the first embodiment.

As in the second embodiment, the stage control system 1
9 outputs the cleaning stage drive instruction MS2 while confirming the position of the cleaning stage CST based on the position information (or speed information) SP2, and controls the cleaning stage CST via the cleaning stage drive unit 58. .

In the projection exposure apparatus of the present embodiment, pattern transfer is performed as follows.

First, prior to the transfer of the pattern onto the wafer W, the exposed substrate facing surface of the objective lens OB of the projection optical system PL is cleaned. FIG. 9 shows a process of cleaning the objective lens OB in the present embodiment. Note that, in FIG. 9, as in FIG. 5, the projection optical system P
The cross section of the vicinity of the L objective lens OB and the cleaning member 8 is shown.

In the cleaning, as in the second embodiment,
First, in response to a command from main controller 20, stage control system 1
9 retracts the wafer stage WST from below the projection optical system PL via the wafer stage driving unit 24, and then, via the cleaning stage driving unit 58, the cleaning stage CS.
T is moved in the X and Y directions, and the cleaning device 60 is moved to the projection optical system P.
Move below L. After that, the stage control system 19 outputs the elevator 38 drive instruction MC2, raises the elevator 38, and brings the flexible member 34 of the cleaning member 8 into contact with the exposed substrate facing surface of the objective lens OB (FIG. 9 ( a)).

Next, in response to a command from the main controller 20, the stage control system 19 checks the position of the cleaning stage CST based on the position information (or speed information) SP2 of the cleaning stage CST while driving the cleaning stage CST. Instruction MS
2 is output, and the cleaning stage CST is reciprocated in at least one of the X direction and the Y direction via the cleaning stage driving unit 58 to rub the flexible member 34 against the substrate facing surface of the objective lens OB. (See FIG. 9B). Thus, the dirt attached to the substrate facing surface of the objective lens OB is cleaned. In FIG. 9B, FIG.
As in (b), only the reciprocating motion of wafer stage WST in the X direction is indicated by arrow X1.

Next, in response to a command from main controller 20,
The stage control system 19 outputs the elevation drive instruction MC2,
The elevator 38 is lowered to separate the ultrasonic vibrator 40 from the projection optical system PL.

After the cleaning operation is completed as described above, the wafer W is placed in the wafer holder 9 similarly to the first embodiment.
After the alignment, the reticle R is illuminated with the exposure illumination light generated in the illumination system, and the pattern drawn on the reticle R is projected onto the wafer W by the projection optical system PL. Is exposed to perform pattern transfer.

According to the present embodiment, as in the second embodiment, prior to the transfer, the wafer W
Of the optical member (objective lens OB) of the projection optical system PL disposed closest to the surface to be exposed, such as a photosensitive agent, is removed from the substrate facing surface of the optical member. At least, it is possible to perform suitable transfer by bringing the projection optical system PL and the wafer W close to each other without any intervening matter other than the atmosphere between the projection optical system PL and the wafer W.

As in the first embodiment, the relationship between dirt and the number of transfers and the light energy applied to the wafer W is measured, and the number of exposures until the clean substrate facing surface reaches a predetermined unacceptable level of dirt. By performing the cleaning operation periodically, for example, every time a predetermined number of transfers or irradiation of a predetermined amount of light energy is performed, or by performing a cleaning operation periodically before the irradiation, the projection exposure apparatus is cleaned. Therefore, it is not necessary to stop frequently, and the productivity is improved. Further, the same deformation of the cleaning member 8 as in the first embodiment is possible.

<< Fourth Embodiment >> A projection exposure apparatus and a projection exposure method according to a fourth embodiment of the present invention will be described below with reference to FIGS. In the description of the present embodiment, the same reference numerals are given to the same elements as the elements in the above description, and the overlapping description will be omitted.

In the projection exposure apparatus of the present embodiment, the cleaning member 8 in the projection exposure apparatus of the first embodiment shown in FIG.
The feature is that the schematic configuration in FIG. 10 is replaced by a cleaning device 62 shown in a cross section. Then, the objective lens OB constituting the projection optical system PL is cleaned using the cleaning device 62 at times other than the time of transfer.

As shown in FIG. 10, the cleaning device 62 has a drive unit 68 fixed to a projection optical system PL via a support member 70 extending in the horizontal direction, and one end 64a of the drive unit 68 is vertically attached to the drive unit 68. Holding member 64 composed of an L-shaped member rotatably supported toward
And a flexible member 66 held horizontally at the other end portion 64b of the main body. The flexible member 66 is driven by a driving mechanism (not shown) including a motor built in the driving section 68, using one end (vertical portion) 64a of the holding member 64 as a rotation axis and the other end 64b.
10 and is moved integrally with the holding member 64 in a vertical direction (Z direction) parallel to the paper surface.

Such swing and vertical movement are controlled by the stage control system 19. That is, the driving unit 6
8 is a Z drive instruction ZMV output from the stage control system 19.
, The holding member 64 is driven in the Z direction, and the holding member 64 is rotationally driven with the one end 64a as a rotation axis in accordance with the rotation drive instruction RMV output from the stage control system 19. The movement of the holding member 64 is monitored by a limit switch (not shown), a position sensor, a rotation sensor, and the like. Here, a cleaning device is configured by the holding member 64 and the flexible member 66.

In the projection exposure apparatus of the present embodiment, pattern transfer is performed as follows.

First, prior to the transfer of the pattern onto the wafer W, the exposed substrate facing surface of the objective lens OB of the projection optical system PL is cleaned. FIG. 11 illustrates a process of cleaning the objective lens OB in the present embodiment. FIG.
In FIG. 1, for clarification of the description, a cross section of the vicinity of the objective lens OB of the projection optical system PL and the flexible member 66 are shown.

In cleaning, first, the flexible member 66 is initially retracted from below the projection optical system PL (FIG. 11).
(Refer to (a)), the stage control system 19 sends the Z drive instruction Z
The MV and the rotation drive instruction RMV are sequentially output, and the drive unit 68
The flexible member 66 is brought into contact with the substrate facing surface of the objective lens OB by moving the holding member 64 through (see FIG. 11B).

Next, in response to a command from the main controller 20, the stage control system 19 outputs the rotation drive RMV,
8, the flexible member 66 is swung to rub the flexible member 66 against the substrate facing surface of the objective lens OB (FIG. 1).
1 (c)). Thus, the dirt attached to the substrate facing surface of the objective lens OB is cleaned.

Next, in response to a command from main controller 20,
The stage control system 19 sequentially outputs the Z drive instruction ZMV and the rotation drive instruction RMV, and moves the holding member 64 to the initial position.

After the cleaning operation is completed as described above, the wafer W is placed in the wafer holder 9 as in the first embodiment.
After performing positioning and alignment, the reticle R is illuminated with exposure illumination light generated by the illumination system, and the pattern drawn on the reticle R is projected onto the wafer W by the projection optical system PL.
The wafer W is exposed and pattern transfer is performed.

According to the present embodiment, as in the second embodiment, prior to the transfer, the wafer W
Of the optical member (objective lens OB) of the projection optical system PL disposed closest to the surface to be exposed, such as a photosensitive agent, is removed from the substrate facing surface of the optical member. It is possible to perform a suitable transfer by bringing the projection optical system PL and the wafer W close to each other with few inclusions other than the atmosphere between the projection optical system PL and the wafer W.

As in the first embodiment, the relationship between dirt and the number of transfers and the amount of light energy applied to the wafer W is measured, and the exposure is performed until the clean substrate facing surface reaches a predetermined unacceptable level. The projection exposure apparatus can be cleaned by performing the cleaning operation periodically, for example, each time a predetermined number of transfers or irradiation of a predetermined amount of light energy is performed or by evaluating the limit number of times of transfer, which is the number of times. For this reason, it is not necessary to stop frequently, so that the productivity is improved.

Further, the deformation of the flexible member 66 can be similar to the deformation of the flexible member 34 in the first embodiment.

<< Fifth Embodiment >> A projection exposure apparatus and a projection exposure method according to a fifth embodiment of the present invention will be described below with reference to FIGS. In the description of the present embodiment, the same reference numerals are given to the same elements as the elements in the above description, and the overlapping description will be omitted.

In the projection exposure apparatus of the present embodiment, the cleaning member 8 in the projection exposure apparatus of the first embodiment shown in FIG.
FIG. 12 is characterized in that it is replaced with a solution ejector 72 mounted on a cleaning stage CST different from the substrate stage WST whose schematic configuration is shown in cross section. And
The objective lens OB constituting the projection optical system PL is cleaned using the solution ejector 72 at times other than at the time of transfer.

The solution launcher 72 is disposed on the cleaning stage CST as shown in FIG. The solution launcher 72 is mounted on a rotation drive 74 that rotates the solution launcher 72 in response to the rotation drive instruction RDV output from the stage control system 19, and is operated in response to an instruction from the main controller 20. A droplet to which the sound wave vibration is applied is fired.

The cleaning stage CST is controlled by the stage control system 19 as in the second embodiment. The rotation driver 74 has a rotation sensor (not shown), and the rotation driving operation is monitored.

The solution launcher 72 includes a liquid tank 76 for storing the cleaning solution, flow path setting members 78a and 78b for setting the flow path of the cleaning solution taken out of the liquid tank 76, and a main controller 20. An ultrasonic vibrator 80 that ultrasonically vibrates according to the output ultrasonic vibration instruction SS2 to apply ultrasonic vibration to the cleaning solution in the flow path in the flow path setting member 78b, and flow path setting members 78a and 78b. Nozzle 82 for firing the cleaning solution through the nozzle, and firing instruction P output by main controller 20
The cleaning solution in the flow passage setting members 78a, 78a, 7
Pump 84 driven towards nozzle 82 via 8b
And a container 86.

Here, as in the second embodiment, the cleaning solution is a solution containing high-purity water, acetone, or a solvent for a photosensitive agent, and may damage the objective lens OB and its coat. No solution can be used.

In the projection exposure apparatus of the present embodiment, transfer is performed as follows.

First, prior to the pattern transfer to the wafer W, the exposed surface of the projection optical system PL facing the substrate facing the objective lens OB is cleaned. FIG. 13 shows steps of a cleaning operation of the objective lens OB in the present embodiment.

At the time of cleaning, first, in response to a command from main controller 20, stage control system 19 causes wafer stage WST to project projection optical system P through wafer stage drive unit 24.
Retreat from below L. Continue with cleaning stage C
The cleaning stage drive unit 58 outputs the cleaning stage drive instruction MS2 while confirming the position of the cleaning stage CST based on the position information (or speed information) SP2 of the ST.
When the cleaning solution is ejected from the nozzle 82 below the projection optical system PL by moving the cleaning stage CST in the X and Y directions via the The OB is moved to a position where it reaches the substrate facing surface.

Next, main controller 20 issues ultrasonic vibration instruction S
S2 and the launch instruction PDV are output, the ultrasonic vibrator 80 is ultrasonically vibrated, and the cleaning solution in the liquid tank 76 is supplied to the flow path. As a result, the flow path setting member 78 in the flow path
Ultrasonic vibration is applied to the cleaning liquid in b, and the ultrasonically vibrating cleaning solution is emitted from the nozzle 82 toward the objective lens OB. Thus, the substrate facing surface of the objective lens OB is cleaned by the cleaning solution (see FIG. 13A).

Next, the stage control system 19 outputs a rotation drive instruction RDV, and the
Is rotated by 180 ° in the XY plane, and the cleaning stage drive instruction MS2 is output while confirming the position of the cleaning stage CST based on the position information (or speed information) SP2 of the cleaning stage CST. The cleaning stage CST is moved in the XY directions via the driving unit 58 to move the ultrasonic cleaning device 40 below the projection optical system PL, and when the cleaning solution is emitted from the nozzle 82, the cleaning solution is discharged. Is moved to a position where it reaches the substrate facing surface of the objective lens OB.

Next, main controller 20 issues ultrasonic vibration instruction S
S2 and the launch instruction PDV are output, and the cleaning solution that is ultrasonically vibrated is launched from the nozzle 82 toward the objective lens OB, and the substrate facing surface of the objective lens OB is cleaned.

After the cleaning operation is completed as described above, the stage control system 19 retreats the cleaning stage CST from below the projection optical system PL via the cleaner driving unit 58. Then, as in the first embodiment, after the wafer W is held by the wafer holder 9 and aligned, the reticle R is illuminated with the exposure illumination light generated by the illumination system.
Is projected onto the wafer W by the projection optical system PL, the wafer W is exposed, and the pattern is transferred.

According to the present embodiment, as in the second embodiment, prior to the transfer, the wafer W
Of the optical member (objective lens OB) of the projection optical system PL disposed closest to the surface to be exposed, such as a photosensitive agent, is removed from the substrate facing surface of the optical member. It is possible to perform a suitable transfer by bringing the projection optical system PL and the wafer W close to each other with few inclusions other than the atmosphere between the projection optical system PL and the wafer W.

As in the first embodiment, the relationship between dirt and the number of transfers and the amount of light energy applied to the wafer W is measured, and the exposure is performed until the clean substrate-facing surface reaches a predetermined unacceptable level. The projection exposure apparatus can be cleaned by performing the cleaning operation periodically, for example, each time a predetermined number of transfers or irradiation of a predetermined amount of light energy is performed or by evaluating the limit number of times of transfer, which is the number of times. For this reason, it is not necessary to stop frequently, so that the productivity is improved.

In the present embodiment, the cleaning solution is emitted toward the objective lens OB in two different directions. However, the cleaning solution may be emitted in only one direction, or the cleaning solution may be emitted in three different directions. It is also possible to fire with the above.

In the present embodiment, for example, the first, third, or fourth
It is possible to combine with the embodiment, and by executing the cleaning operation of each of the combined embodiments after executing the cleaning operation in the present embodiment, it is possible to also collect the cleaning solution.

In this embodiment, the cleaning solution is subjected to the ultrasonic vibration. However, the cleaning solution may be sprayed on the objective lens OB without applying the ultrasonic vibration. Also in this case, for example, it is possible to combine with the first, third, or fourth embodiment. After the cleaning operation in this embodiment is performed, the cleaning operation of each of the combined embodiments is performed, so that the cleaning operation is performed. It can also serve as a solution recovery.

Sixth Embodiment A projection exposure apparatus and a projection exposure method according to a sixth embodiment of the present invention will be described below with reference to FIGS. In the description of the present embodiment, the same reference numerals are given to the same elements as the elements in the above description, and the overlapping description will be omitted.

The projection exposure apparatus of the present embodiment differs from the projection exposure apparatus of the first embodiment shown in FIG. 1 in that the cleaning member 8 is replaced with an ultrasonic cleaner 40 whose schematic configuration is shown in cross section in FIG. It is characterized in that the dirt measuring device 84 is employed. Then, the dirt of the objective lens OB constituting the projection optical system PL is measured at a time other than at the time of transfer by the dirt measuring device 84,
Cleaning is performed by the ultrasonic cleaner 40 as necessary.

The dirt measuring device 84 includes a light source 86 that emits measuring light in response to a light emitting instruction PSD output from the main controller 20, an optical system having a half mirror 88 and lenses 90 and 92, and an objective lens OB. The photodetector includes a photodetector 94 that detects the measurement light reflected by the substrate facing surface, and a dirt measurement processing unit 96 that measures dirt from the detection result DDT output from the photodetector 94. Then, the measurement light emitted from the light source 86 is applied to the substrate facing surface of the objective lens OB via the half mirror 88 and the lens 90 sequentially, and
The measurement light reflected by the substrate facing surface of the objective lens OB passes through the lens 90, the half mirror 88, and the lens 92 in order, and forms an image on the light receiving surface of the photodetector 94. That is, in the present embodiment, the half mirror 88 and the lens 90
Constitute an irradiation optical system, the light source 86 and the illumination optical system constitute an illumination system, and the lens 90, the half mirror 88, and the lens 92 constitute an imaging optical system.

Here, as the photodetector 94, a photodetector having two-dimensionally arranged photoelectric conversion units, for example, a two-dimensional charge-coupled device (CCD) can be suitably used.

In the projection exposure apparatus of the present embodiment, pattern transfer is performed as follows.

First, prior to the transfer of the pattern onto the wafer W, the dirt on the exposed substrate facing surface of the objective lens OB of the projection optical system PL is measured and, if necessary, cleaned. FIG.
2 shows a process of cleaning the objective lens OB in the present embodiment.

First, in response to a command from main controller 20, stage control system 19 retracts wafer stage WST from below projection optical system PL via wafer stage drive unit 24. Subsequently, while checking the position of the cleaning stage CST based on the position information (or speed information) SP2 of the cleaning stage CST, the cleaning stage drive instruction MS is issued.
2 and the cleaning stage CST is moved in the X and Y directions via the cleaning stage
The optical system No. 4 is moved to a position below the projection optical system PL so that the measurement light can be irradiated on the substrate facing surface of the objective lens OB.

Next, main controller 20 outputs light emission instruction PSD, causes light source 86 to emit light, and generates measurement light. The measurement light emitted from the light source 86 is applied to the substrate facing surface of the objective lens OB via the irradiation optical system. Then, the measurement light reflected on the substrate facing surface of the objective lens OB enters the light receiving surface of the photodetector 94 via the imaging optical system, and is detected by the photodetector 94. The detection result of the photodetector 94 is notified to the dirt measurement processing unit 96, and dirt is measured (FIG. 1).
5 (a)).

Next, based on the measured dirt, main controller 20 determines whether or not cleaning is necessary. This determination is made from the viewpoint of whether or not the next exposure can be performed in a state where the contamination is equal to or less than a predetermined allowable limit value. If it can be done, a decision is made as to whether or not cleaning is necessary, and if not, a decision is made as to whether cleaning is necessary.

If it is determined that cleaning is not necessary, the stage control system 19 retreats the cleaning stage CST from below the projection optical system PL via the cleaning device drive unit 58. Then, similarly to the first embodiment, the wafer W is placed in the wafer holder 9.
After the alignment, the reticle R is illuminated with the exposure illumination light generated in the illumination system, and the pattern drawn on the reticle R is projected onto the wafer W by the projection optical system PL. Is exposed.

If it is determined that cleaning is necessary, the stage control system 19 sends the position information (or speed information) SP of the cleaning stage CST in response to a command from the main controller 20.
The cleaning stage drive instruction MS2 is output while confirming the position of the cleaning stage based on the cleaning stage 2, and the cleaning stage CST is moved in the X and Y directions via the cleaning stage driving unit 58 to move the ultrasonic cleaning device 40. It is moved below the projection optical system PL (see FIG. 15B). Thereafter, the cleaning of the objective lens OB is performed in the same manner as in the second embodiment.

Next, in response to a command from the main controller 20, the stage control system 19 outputs a cleaning stage drive instruction MS2 based on the position information (or speed information) SP2 of the cleaning stage CST. The cleaning stage CST is moved in the X and Y directions via the driving unit 58 so that the optical system of the dirt measuring device 84 is below the projection optical system PL and the measurement light can be applied to the substrate facing surface of the objective lens OB. Move to Then, the dirt on the substrate facing surface of the objective lens OB is measured by the dirt measuring device 84 in the same manner as the dirt measurement described above, and the cleaning effect is confirmed.

If it is confirmed that the cleaning effect is sufficient, the stage control system 19 causes the cleaning stage driving unit 58 to operate.
, The cleaning stage CST is retracted from below the projection optical system PL. Then, similarly to the first embodiment, after holding the wafer W with the wafer holder 9 and performing positioning,
The reticle R is illuminated with the illumination light for exposure generated in the illumination system,
The pattern drawn on the reticle R is projected onto the wafer W by the projection optical system PL, the wafer W is exposed, and the pattern is transferred. If the cleaning effect is insufficient, the cleaning operation and the confirmation of the cleaning effect are repeated.

According to the present embodiment, prior to the transfer, the optical member (objective lens O) of the projection optical system PL disposed closest to the exposed surface of the wafer W by the previous transfer.
B) Measure the dirt such as the photosensitive agent adhered to the substrate facing surface, and
Since cleaning is performed as necessary, the dirt on the substrate facing surface of the optical member is small, and the projection optical system PL and the wafer W can be cleaned in a state where there is no inclusion other than the atmosphere between the projection optical system PL and the wafer W.
And a suitable transfer can be reliably performed.

In this embodiment, the dirt measuring device is combined with the second embodiment, but it is also possible to combine the dirt measuring device of this embodiment with the first, third to fifth embodiments.

In the measurement of dirt, it is possible to measure dirt by using illumination light for exposure as measurement light and detecting light transmitted through the objective lens OB.
It is necessary to select a member that transmits ultraviolet light as an optical member constituting the optical system for measurement, and it is necessary to note that there is less room for selecting an optical member.

<< Seventh Embodiment >> Hereinafter, a projection exposure apparatus and a projection exposure method according to a seventh embodiment of the present invention will be described with reference to FIGS. In the description of the present embodiment, the same reference numerals are given to the same elements as the elements in the above description, and the overlapping description will be omitted.

The projection exposure apparatus of the present embodiment performs projection exposure of the wafer W, and also prevents contamination-causing substances from reaching the optical member of the projection optical system disposed closest to the wafer W during transfer. Things. FIG. 16 shows a schematic configuration of the projection exposure apparatus of the present embodiment.

As shown in FIG. 16, in the projection exposure apparatus of the present embodiment, the cleaning member 8 in the projection exposure apparatus of the first embodiment shown in FIG. The feature is that the device 98 is replaced.

As shown in FIG. 17, the dirt preventing device 98 includes flow path setting members 102a, 102b, 104a, and 104b for setting a flow path of the atmospheric gas, and an atmosphere from the open end of the flow path setting member 102b. Suction pump 10 for supplying an atmosphere taken into flow path setting member 102a via intake flow path setting member 102b
6 and a discharge pump 108 for discharging the atmosphere passing through the flow path setting member 104a from the open end of the flow path setting member 104b. Then, the flow path setting member 10
Although the open end of 2a and the open end of the flow path setting member 104a are connected in terms of the atmosphere flow, they are physically separated at least in the vicinity of the objective lens OB. Until stretched. Therefore, the illumination light for exposure emitted from the projection optical system PL reaches the wafer W only through the atmosphere.

Suction pump 106 performs a suction operation in response to suction instruction PD1 output from main controller 20,
The discharge pump 108 performs a discharge operation according to the discharge instruction PD2 output from the main control device 20.

In the projection exposure apparatus of the present embodiment, pattern transfer is performed as follows.

First, main controller 20 controls suction instruction PD1.
And the discharge instruction PD2, and outputs the flow paths 102b,
A flow of the atmospheric gas sequentially passing through 2a, 104a, and 104b is generated. Next, after holding the wafer W with the wafer holder 9 and performing alignment for exposure, the reticle R is illuminated with exposure illumination light generated by the illumination system, and the pattern drawn on the reticle R is projected onto the projection optical system PL. Is projected onto the wafer W, the wafer W is exposed, and the pattern is transferred.

According to the projection exposure apparatus of this embodiment, first, the objective lens OB of the projection optical system PL, ie, the wafer W
Is performed while flowing the atmospheric gas near the substrate facing surface of the optical member arranged near the substrate. Therefore,
Due to the flow of the atmospheric gas, the wafer W as a sensitive substrate
The transfer is performed in a state where there is no inclusion other than the atmospheric gas on the traveling path of the exposure illumination light between the projection optical system and the wafer W while preventing the contamination-causing substance generated in the above from reaching the objective lens OB. . As a result, the projection optical system and the wafer W are brought close to each other in a state where the dirt on the substrate facing surface of the objective lens OB is small and there is no intervening substance other than the atmospheric gas between the projection optical system and the wafer W. Can be performed.

In this embodiment, the atmospheric gas is made to flow, but another kind of gas may be made to flow.

The present invention is not limited to the above embodiment, but can be variously modified. For example, in each of the above embodiments, the optical member disposed closest to the wafer W on the optical path of the exposure illumination light at the time of transfer is used as the objective lens. For example, when an optical member for correcting an optical path is provided, each embodiment can be applied to the optical member for correcting an optical path as a cleaning target or a dirt prevention target.

The optical member to be cleaned is not limited to the optical member at the tip of the projection optical system. For example, a focus detection optical system for detecting the position of the wafer W or an optical member at the distal end of the alignment optical system can be a cleaning target.

Further, the dirt detecting device according to the sixth embodiment is not provided together with the cleaning device, but is provided alone, and before the measurement result by the dirt measuring device exceeds the allowable limit value, the dirt detecting device is used. It is possible to replace the optical member.

In each of the above embodiments, the wafer stage or a cleaning stage different from the wafer stage may be a guideless type stage which is driven to float on a two-dimensional planar motor. In addition, the stage may have a mechanical guide.

[0179]

As described in detail above, claim 1 is as follows.
According to the projection exposure apparatuses of (1) to (7), prior to the transfer, the optical member is cleaned by cleaning the photosensitive member or the like adhered to the optical member disposed near the exposed surface of the sensitive substrate by the previous transfer. This has an unprecedented excellent effect of reducing dirt and improving exposure accuracy.

According to the projection exposure apparatus of the eighth and ninth aspects, prior to the transfer,
The dirt of the photosensitizer and the like adhered to the optical member placed near the surface to be exposed of the sensitive substrate can be measured, and the optical member can be cleaned or replaced as necessary, so that the dirt on the optical member is reduced. There is an unprecedented excellent effect that the exposure accuracy can be improved and the productivity can be improved.

Further, according to the projection exposure apparatus of the tenth and eleventh aspects, the gas between the optical member disposed near the sensitive substrate and the sensitive substrate is caused to flow, so that the optical member of the substance causing a stain is formed. Prevents contamination of the optical members, improving exposure accuracy,
There is an unprecedented excellent effect that productivity can be improved.

According to the projection exposure apparatus of the twelfth aspect, the projection optical system arranged on the optical path of the illumination light for exposure and closest to the sensitive substrate due to the adhesion of the stain-causing substance during transfer. There is no need to worry about contamination of the optical members constituting the system, and it is possible to design a projection optical system in which the projection optical system is close to the sensitive substrate, so that a projection optical system with a higher numerical aperture can be easily realized. There is an unprecedented superior effect.

According to the projection exposure apparatus of the thirteenth aspect, the optical member at the tip of the optical system for aligning the sensitive substrate to which the photosensitive agent or the like is liable to adhere is cleaned, and the dirt is measured.
Alternatively, since it is an object to prevent contamination, there is an unprecedented superior effect that the contamination of the optical member is reduced and the exposure accuracy can be improved.

Further, according to the projection exposure method of the present invention, a cleaning step is first performed, and the photosensitive agent adhered to the optical member arranged near the exposed surface of the sensitive substrate by the previous transfer. Since the transfer step is performed after the dirt such as is cleaned and the substrate facing surface is cleaned, there is an unprecedented excellent effect that the dirt on the optical member is reduced and the exposure accuracy can be improved.

According to the projection exposure method of the present invention, prior to the execution of the transfer, first, the dirt measuring step is executed to measure the dirt of the optical component, and in the judging step, the transfer is performed based on the measurement result. Is determined, the dirt on the substrate facing surface of the optical member is reduced, and there is an unprecedented excellent effect that the exposure accuracy can be improved and the productivity can be improved.

[Brief description of the drawings]

FIG. 1 is a diagram illustrating a schematic configuration of a projection exposure apparatus according to a first embodiment.

FIG. 2 is a view for explaining the principle of scanning exposure of the apparatus of FIG. 1;

FIG. 3 is a diagram showing a configuration of a center-up of the apparatus of FIG. 1;

FIG. 4 is a diagram showing a configuration of a cleaning device of the apparatus of FIG. 1;

FIG. 5 is a view for explaining a cleaning step by the apparatus of FIG. 1;

FIG. 6 is a diagram illustrating a configuration of a cleaning device of a projection exposure apparatus according to a second embodiment.

FIG. 7 is a view for explaining a cleaning step performed by the projection exposure apparatus according to the second embodiment.

FIG. 8 is a diagram illustrating a configuration of a cleaning device of a projection exposure apparatus according to a third embodiment.

FIG. 9 is a view for explaining a cleaning step by the projection exposure apparatus of the third embodiment.

FIG. 10 is a diagram illustrating a configuration of a cleaning device of a projection exposure apparatus according to a fourth embodiment.

FIG. 11 is a view for explaining a cleaning step by a projection exposure apparatus according to a fourth embodiment.

FIG. 12 is a diagram illustrating a configuration of a cleaning device of a projection exposure apparatus according to a fifth embodiment.

FIG. 13 is a view for explaining a cleaning step performed by the projection exposure apparatus according to the fifth embodiment.

FIG. 14 is a diagram illustrating a configuration of a cleaning device of a projection exposure apparatus according to a sixth embodiment.

FIG. 15 is a view for explaining a cleaning step by the projection exposure apparatus of the sixth embodiment.

FIG. 16 is a diagram illustrating a schematic configuration of a projection exposure apparatus according to a seventh embodiment.

17 is a diagram showing a configuration of a stain prevention device of the device of FIG.

[Explanation of symbols]

8 Cleaning Member (Cleaning Device) 34 Flexible Member (Part of Cleaning Device) 38 Elevator (Part of Moving Mechanism) 40 Ultrasonic Cleaner (Cleaning Device) 54 Moving Mirror (Part of Moving Mechanism) 56 Cleaner Interferometer (part of moving mechanism) 58 Cleaning stage drive (part of moving mechanism) 62 Cleaning device 64 Holding member (part of cleaning device) 66 Flexible member (part of cleaning device) 68 Drive unit (moving) (Part of mechanism) 72 Solution ejector (cleaning device) 74 Rotary driver (part of moving mechanism) 80 Ultrasonic vibrator 84 Dirt measuring device 94 Photodetector 98 Dirt prevention device 102 Flow path setting member 104 Flow path setting Member 106 Pump (atmosphere gas supply) R Reticle W Wafer (sensitive substrate) PL Projection optical system WSD Wafer stage CSD Cleaning stage (part of moving mechanism and driver)

Claims (17)

[Claims] 1. A projection exposure apparatus for transferring a pattern formed on a mask onto a sensitive substrate via a projection optical system, wherein a cleaning device for cleaning an optical member disposed at a predetermined position is provided. Projection exposure equipment. 2. The projection exposure apparatus according to claim 1, wherein the cleaning device is installed on a stage that holds the sensitive substrate. 3. The projection exposure apparatus according to claim 2, wherein the cleaning device is mounted on a driving device for vertically moving the sensitive substrate on the stage. 4. The projection exposure apparatus according to claim 1, wherein the cleaning device is mounted on a moving mechanism different from a stage that holds the sensitive substrate. 5. The projection exposure apparatus according to claim 2, wherein the cleaning device includes an ultrasonic cleaner for immersing a cleaning target portion of the optical member in a cleaning solution and performing ultrasonic cleaning. . 6. The projection exposure apparatus according to claim 2, wherein the cleaning device includes a cleaning member that contacts the substrate facing surface of the optical member to clean the substrate facing surface. . 7. The projection exposure apparatus according to claim 2, wherein the cleaning device includes a solution ejector that sprays a cleaning solution onto the substrate facing surface of the optical member. 8. A projection exposure apparatus for transferring a pattern formed on a mask onto a sensitive substrate via a projection optical system, wherein a dirt measuring device for measuring dirt on an optical member disposed at a predetermined position is provided. A projection exposure apparatus. 9. The dirt measuring device includes: an irradiating optical system that irradiates the optical member with light; a photodetector that detects light from the optical member; and the optical device based on a detection result of the photodetector. 9. The projection exposure apparatus according to claim 8, further comprising: a dirt measuring processor for measuring dirt on the member. 10. A projection exposure apparatus for transferring a pattern formed on a mask onto a sensitive substrate via a projection optical system, comprising: an optical member disposed near an exposure surface of the sensitive substrate; A projection preventing apparatus provided with an antifouling device for causing a gas to flow between the substrate and the foreign material generated from the sensitive substrate to prevent the foreign material from reaching the optical member. 11. A contamination prevention device, comprising: a flow path setting member for setting a flow path of the gas near the substrate facing surface; and a gas supply for supplying the gas to the flow path set by the flow path setting member. The projection exposure apparatus according to claim 10, further comprising a device. 12. The optical member according to claim 1, wherein the optical member is an optical member disposed on an optical path of illumination light for exposure and closest to the sensitive substrate.
The projection exposure apparatus according to any one of the above. 13. The projection exposure according to claim 1, wherein the optical member is an optical member at a tip end of an optical system for positioning the sensitive substrate. apparatus. 14. A projection exposure method for transferring a pattern formed on a mask onto a sensitive substrate via a projection optical system, comprising: a cleaning step for cleaning dirt on an optical member disposed at a predetermined position; Transferring the pattern formed on the mask onto the sensitive substrate via the projection optical system after cleaning the optical member. 15. The projection exposure method according to claim 14, wherein the optical member is an optical member disposed on an optical path of illumination light for exposure and closest to the sensitive substrate. . 16. Performed prior to the cleaning step,
A dirt evaluation step of measuring the relationship between the dirt of the optical member and the number of transfers, and evaluating the limit number of transfers that is the number of exposures until the substrate facing surface of the optical member reaches a predetermined unacceptable dirt from a clean state. 15. The projection exposure method according to claim 14, further comprising: performing the cleaning step before the number of times of transfer after the previous execution of the cleaning step reaches the limit number of times of transfer. 17. A projection exposure method for transferring a pattern formed on a mask onto a sensitive substrate via a projection optical system, wherein a dirt measuring step for measuring dirt on an optical member arranged at a predetermined position; And a judging step of judging whether or not to execute the transfer based on the measurement result obtained in the measuring step.