JP2001135568A - Scanning projection aligner and method of fabrication for device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent or reduce thermal deformation of an original plate effectively and to prevent thermal deformation of an original plate without having any adverse effect on the measurement accuracy of position of the original plate. SOLUTION: The scanning projection aligner for exposing the pattern of an original plate R onto a substrate W while moving the original plate and the substrate relative to a projection optical system 8 comprises means 12 for supplying air toward the upper surface of the original plate during movement wherein the air supply means has an air supply opening elongated in the direction substantially orthogonal to the scanning direction or a plurality of air supply openings arranged in that direction. The air supply means also has first and second air supply openings located on the opposite sides of a specified illumination region on the original plate in the scanning direction. The air supply openings of the air supply means are arranged to supply air from an interferometer 16 for measuring the position of an original plate stage RST toward the optical axis IX side of the projection optical system when viewed from the scanning direction. Furthermore, an exhaust means is provided between the air supply openings of the air supply means and the interferometer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used, for example, when a semiconductor element is manufactured by a photolithography process, and sequentially exposes a pattern image of an original plate while scanning and moving an original plate and a photosensitive substrate in synchronization during exposure. The present invention relates to a so-called slit-scan exposure type or step-and-scan type projection exposure apparatus for exposing a substrate, and a device manufacturing method using the same.

[0002]

2. Description of the Related Art Generally, in a photolithography process for manufacturing a semiconductor integrated circuit or the like, a pattern image of a photomask or a reticle (hereinafter, collectively referred to as a "mask") is formed on a wafer (or A projection exposure apparatus that performs exposure on a glass plate or the like is used. In such a projection exposure apparatus, as the circuit pattern to be transferred becomes finer, the allowable range of the amount of variation in the imaging characteristics of the projected image by the projection optical system becomes narrower. Therefore, conventionally, in a projection exposure apparatus,
JP-A-60-78455 and JP-A-63-78455 have been proposed in order to correct the amount of change in imaging characteristics (for example, magnification, focal position, etc.) caused by the projection optical system absorbing illumination light.
As disclosed in Japanese Patent No. 58349 or the like, there is provided an imaging characteristic correcting mechanism for detecting the amount of light incident on the projection optical system and correcting the amount of change in the imaging characteristics of the projection optical system according to the detected amount of light. ing.

For example, the mechanism disclosed in Japanese Patent Application Laid-Open No. Sho 60-78455 will be briefly described. This mechanism preliminarily creates a model corresponding to the fluctuation characteristics of the imaging characteristics of the projection optical system, and mounts a model on the wafer. The amount of light energy incident on the projection optical system at predetermined time intervals is determined by a photoelectric sensor or the like on the wafer stage placed, and the integrated value of the amount of light energy is applied to the model to calculate the amount of change in imaging characteristics. Things. In this case, the exposure time for obtaining the integral value of the light energy incident on the projection optical system is calculated, for example, by constantly monitoring a signal indicating that the shutter for opening and closing the illumination light is in an open state. Therefore, it is possible to calculate the amount of change in the imaging characteristics of the current projection optical system according to the model, and perform correction based on this amount of change. Thus, the problem of the fluctuation of the imaging characteristics due to the absorption of the illumination light of the projection optical system has been once solved.

[0004] However, since the illumination light also passes through the mask, the mask is thermally deformed by the absorption of the illumination light, so that there is an inconvenience that the imaging characteristics also change. In particular, since the mask is patterned with a light-shielding film such as a chrome film, unlike a glass substrate part with high transmittance,
Large heat absorption in the light shielding film. Furthermore, in recent years, there has been a tendency to adopt a technique of lowering the reflection of a light-shielding film on a mask for the purpose of preventing flare of an optical system. However, heat absorption by the light-shielding film has further increased.

In addition, the circuit pattern formed by the light-shielding film of the mask is not always uniformly distributed over the entire mask, but may be unevenly distributed. In this case, there is a possibility that the temperature of the mask locally increases and anisotropic distortion occurs. Similarly, when only a part of the mask pattern is exposed using a variable field stop (reticle blind) or the like, anisotropic distortion may occur. Due to the distortion of the mask generated in this way, anisotropic distortion occurs in the projected image. In this case, it is insufficient to correct only the magnification component. Further, regarding the thermal deformation of the mask, it is difficult to uniformly correct the thermal deformation because the amount of thermal deformation, and hence the amount of change in the imaging characteristics, differs depending on the type of the mask used. That is, for example, the amount of change in the imaging characteristic due to thermal deformation of the mask used for adjusting the imaging characteristic at the time of shipment of the projection exposure apparatus can be recognized and corrected as the fluctuation characteristic of the imaging characteristic of the projection exposure apparatus. However, if another mask is used, accurate correction cannot be performed because the amount of thermal deformation is different. In particular, in the case of performing exposure while changing masks one after another, unless the amount of thermal deformation of each mask is taken into consideration, the amount of change in the imaging characteristics may accumulate and cause a large error. As a countermeasure, a projection exposure apparatus that corrects for changes in optical characteristics caused by thermal deformation of the mask by including the thermal absorption of chromium forming the mask pattern, the chromium abundance in the pattern, etc. 4-192
No. 317 is disclosed.

However, since the method of correcting the imaging characteristics disclosed in this publication has been proposed on the premise of a batch exposure method (full field method), a so-called step-and-scan exposure method or a so-called step-and-scan exposure method which has been recently developed has been proposed. There are the following disadvantages when applied to a projection exposure apparatus of the slit scan exposure system (hereinafter, referred to as "scan exposure system"). The scan exposure method illuminates the pattern area of the mask in a slit shape, scans the mask with respect to the slit-shaped illumination area, and synchronizes with the scanning movement to an exposure area conjugate to the slit-shaped illumination area. On the other hand, the mask pattern is sequentially projected and exposed on each shot area of the wafer by scanning and moving the wafer. This scanning exposure method has an advantage that a large area can be exposed without being restricted by the field size of the projection optical system in the scanning direction. However, in such a scan exposure method, since the mask is scanned and moved with respect to the illumination area at the time of exposure, an element to be considered with respect to the mask, that is, a cooling effect of the mask due to the mask scanning increases. The calculation of the amount of thermal deformation is more complicated than in the case of the batch exposure method.

Japanese Patent Application Laid-Open No. 7-147224 discloses a projection exposure apparatus which corrects a change in optical characteristics caused by thermal deformation of a mask in a scan exposure method. In this publication, the relative velocity between the mask and the ambient gas is approximately measured from the value of the position measurement interferometer of the mask stage, and the thermal deformation of the mask is measured from the relative velocity and the irradiation energy to the mask. And a method of performing correction based on the mask, so that air with a constant wind speed always hits the surface of the mask to eliminate the change in the imaging characteristics due to the presence or absence of the mask scanning and the difference in the scanning speed, and always maintain a constant image forming characteristic. A method of making correction has been proposed.

FIG. 3 (a) shows this Japanese Patent Application Laid-Open No. 7-147224.
FIG. 1 shows a main part of a system configuration for maintaining a constant wind speed, which is proposed in Japanese Patent Laid-Open Publication No. H10-209,878. As shown in the figure, in this configuration, the coordinates of the mask stage RST are constantly measured by the interferometer 16. An air outlet 19 of an air blower is arranged at a position in the scanning direction of the mask stage RST facing the interferometer 16 with the mask R interposed therebetween, and air with a variable wind speed is blown from the air outlet 19 to the mask stage RST. I have. Further, an anemometer 20 is fixed to one end of the mask stage RST on the side of the air outlet 19, and the anemometer 20 allows the mask stage RST, and thus the mask R and the atmosphere gas (air) to be connected.
And the relative speed with respect to is measured. Therefore, even if the scanning speed of the mask stage RST changes, the anemometer 2
The relative speed between the mask R and the atmospheric gas can be made constant by controlling the wind speed or air volume of the blower so that the wind speed measured by 0 becomes constant.

[0009]

In the scanning exposure method, synchronous control of scanning on the mask side and scanning on the wafer side and control of each scanning operation are important for exposure performance. The position measurement of the mask stage is performed using an interferometer. Since the measurement optical path of the interferometer is very sensitive to changes in temperature, humidity, and atmospheric pressure, a stable atmosphere is required. However, according to the method proposed in Japanese Patent Application Laid-Open No. Hei 7-147224, the side facing the interferometer with the mask R interposed therebetween (the interferometer is arranged) so that air at a constant wind speed always hits the surface of the mask R. When air is blown onto the surface of the mask R from the side opposite to the place where the gas is blown, the temperature of the gas blown to the mask R whose temperature has increased rises at the mask R portion. The gas whose temperature has risen is as shown in FIG.
It flows into the measurement optical path of the interferometer 16 used for position measurement on the mask side. The inflow of gases having different temperatures causes air fluctuations on the measurement optical path of the interferometer 16, resulting in measurement errors. Therefore, according to the technology disclosed in the publication, the scanning accuracy of the mask stage RST is reduced, and thus the synchronization control accuracy between the mask-side scanning and the wafer-side scanning is reduced.
There is a problem that the scanning exposure performance is reduced.

Further, as described above, Japanese Patent Application Laid-Open No.
In Japanese Patent Publication No. 24, the wind speed blown to the mask R is controlled by an anemometer 20 configured on the mask stage RST, the relative speed between the mask R and the gas in contact with the mask R is made constant, and the image forming characteristic is kept constant. Means for making corrections have been proposed. However, the air outlet 19 for the mask R
Is provided only at one position on the side facing the interferometer 16 with the mask R interposed therebetween. Therefore, the mask stage RS
When the mask stage RST scans in the direction opposite to the flow of gas to be blown, depending on the scanning direction of T,
The relative speed between the mask R and the gas in contact with the mask R is different between the case where scanning is performed in a direction preceded by the flow of the gas to be blown.

When the mask stage RST scans and moves in a direction opposite to the flow of the gas to be blown, the wind speed of the blown gas is VGA, and the scanning speed of the mask stage RST is VS, and the relative speed VG in this case is VG. Is VS + VG
A. When the scanning speed of the mask stage RST is kept constant and the mask stage RST scans in the direction that goes forward with the flow of the blown gas, the wind speed of the blown gas is V
Assuming JA, the relative speed VJ in this case is -VS + VJ
A. To make VG = VJ, VJA = VGA + 2V
It becomes S. That is, when the flow of gas to be blown and the scanning movement direction of the mask stage RST are the same direction, the wind speed necessary for the mask stage R
A wind speed that is twice as high as the speed of ST is required.

Assuming that the wind speed in the reverse direction is 500 mm / s and the scanning speed of the wafer stage is 100 mm / s, the mask stage RST depends on the reduction magnification β of the projection optical system, ie, if β is 1/5, 5 × 100 mm / s =
A scanning speed of 500 mm / s is required. Therefore, in the forward direction, 500 m / s plus 1000 mm / s which is twice the scanning speed of the mask stage RST is added to 1500 m.
A wind speed of m / s would be required. In order to secure a wind speed of 1500 mm / s, a large-sized air blower is required, and when the temperature of the gas to be blown is adjusted, the temperature adjuster also becomes large. In addition, when an air filter is provided in a blowing line to ensure the cleanliness of the gas to be blown, a wind speed of about 500 mm / s is generally required to secure the dust collection efficiency of the filter. The problem that the degree cannot be secured occurs. Further, in the future, in order to improve the throughput of the apparatus, it is necessary to increase the speed of the wafer stage.
There is a problem that the required wind speed becomes higher and more difficult to achieve depending on the required wind speed.

SUMMARY OF THE INVENTION An object of the present invention is to solve the problems of the prior art by using a scanning projection exposure apparatus and a device manufacturing method using the same, whereby thermal deformation of an original plate can be more effectively prevented or reduced. Is to do so. Another object of the present invention is to prevent thermal deformation of an original plate without adversely affecting the position measurement accuracy of the original plate stage.

[0014]

In order to achieve the above object, a first scanning projection exposure apparatus according to the present invention comprises the steps of: scanning a substrate and a substrate with respect to a projection optical system; In a scanning type projection exposure apparatus that exposes upward, a blowing unit that blows air toward the upper surface of the original plate during the scanning movement is provided, and the blowing unit has a shape extending in a direction substantially orthogonal to the direction of the scanning movement. The apparatus is characterized in that it has an air outlet or a plurality of air outlets arranged in a direction substantially perpendicular to the direction of the scanning movement.

The second scanning projection exposure apparatus includes an original stage for performing scanning movement of the original, an interferometer for measuring the position of the original stage, a reflecting mirror fixed to the original stage, and Air blowing means for blowing air toward the upper surface of the original plate, and blowing the air to the original plate and scanning and moving the original plate and the substrate with respect to the projection optical system based on the measurement result of the position, and changing the pattern of the original plate. In a scanning projection exposure apparatus that exposes light onto the substrate, the air outlet is disposed between the projection optical system and the interferometer.

A third scanning projection exposure apparatus according to the first or second scanning projection exposure apparatus, wherein the blowing port is arranged such that a blowing direction is inclined with respect to an optical axis of the projection optical system. It is characterized by having.

A fourth scanning projection exposure apparatus is a scanning projection exposure apparatus that exposes a pattern of the original onto the substrate while scanning and moving the original and the substrate with respect to a projection optical system. An air blower for blowing air toward the upper surface of the original plate, the air blower having first and second air outlets arranged on both sides of a predetermined illumination area on the original plate and in the direction of the scanning movement; It is characterized by the following.

A fifth scanning projection exposure apparatus according to the fourth scanning projection exposure apparatus, wherein the blower means blows and blows air from the first and second blowing ports in accordance with the direction of the scanning movement. It is characterized in that stop or suction can be switched for each air outlet.

A sixth scanning projection exposure apparatus according to the fifth scanning projection exposure apparatus, wherein, during the scanning movement, air is blown from one of the first and second blowing ports on the side of the original sheet in the traveling direction. It is characterized in that it has a means for performing the switching so that the blowing port on the opposite side stops blowing or performs suction.

The seventh scanning projection exposure apparatus includes fourth to sixth
The scanning projection exposure apparatus according to any one of the above, further comprising a housing that covers the first and second air outlets, and a unit that exhausts the inside of the housing.

The eighth scanning projection exposure apparatus includes first to seventh
In any one of the scanning projection exposure apparatus, the original plate stage for performing the scanning movement of the original plate, and an interferometer for measuring the position of the original plate stage and a reflecting mirror fixed to the original plate stage, An exhaust unit is provided between the air outlet and the interferometer.

The ninth scanning projection exposure apparatus includes an original stage for performing scanning movement of the original, an interferometer for measuring the position of the original stage, a reflecting mirror fixed to the original stage, and Air blowing means for blowing air toward the upper surface of the original plate, and blowing the air to the original plate and scanning and moving the original plate and the substrate with respect to the projection optical system based on the measurement result of the position, and changing the pattern of the original plate. In a scanning projection exposure apparatus that exposes light onto the substrate, the blowing means is provided with a blowing port to blow air from the interferometer toward the optical axis of the projection optical system when viewed in the direction of the scanning movement. It is characterized by having been done.

The tenth scanning projection exposure apparatus according to the present invention comprises: an original stage for performing scanning movement of the original;
An interferometer for measuring the position of the original plate and a reflecting mirror fixed to the original plate stage, and an air blowing means for blowing air toward the upper surface of the original plate, for blowing air to the original plate and In a scanning projection exposure apparatus that exposes the pattern of the original plate onto the substrate while scanning and moving the original plate and the substrate with respect to a projection optical system based on the measurement result, the blowing port of the blowing unit, the interferometer, It is characterized by having exhaust means between them.

Further, the device manufacturing method of the present invention uses the scanning projection exposure apparatus according to any one of the first to tenth aspects of the present invention, and performs exposure while blowing air onto the upper surface of the original plate by the blowing means. Is manufactured.

In the configuration of the present invention, when a blow port having a shape extending in a direction substantially perpendicular to the scanning movement direction or a plurality of blow ports arranged in a direction substantially perpendicular to the scanning direction is provided, The air is efficiently blown over the entire surface of the substrate. Further, when the air outlet is disposed between the projection optical system and the interferometer, the original plate is cooled without affecting the optical path measured by the interferometer due to air fluctuation or the like. Further, in a case where the blowing from the first and second blowing ports and the stopping or sucking of the blowing can be switched for each blowing port in accordance with the direction of the scanning movement, for example, the first and second blowing ports may be used. When air is blown from the air outlet on the direction of travel of the original plate, and the air outlet on the opposite side is switched to stop air blowing or perform suction, even when the original plate scans in any direction, The relative velocity with respect to the gas in contact with the surface of the original plate becomes substantially constant, and the cooling efficiency of the original plate is improved. When the first and second air outlets are covered by the housing and the inside of the housing is exhausted, the influence of the interferometer on the measurement optical path is further reduced. Furthermore, by blowing air from the interferometer toward the optical axis side of the projection optical system, or by providing exhaust means between the air outlet and the interferometer, the air flow to the measurement optical path by the interferometer can be improved. The effect will be further reduced.

It should be noted that the various proposed methods of correcting the imaging characteristics and the like shown in the section of the prior art are effective in the present invention, respectively. As a countermeasure against deformation, it is effective to minimize the heat generation, that is, deformation of the original plate itself, and the air-cooling method that minimizes the effect on the interferometer measurement optical path of the original plate stage during air-cooling is called scanning projection. This is important in an exposure apparatus. The present invention focuses on this point.

[0027]

1 shows a schematic configuration of a scanning exposure type projection exposure apparatus according to a first embodiment of the present invention. As shown in the figure, the projection exposure apparatus includes illumination optical systems 1 to 5 for illuminating a predetermined illumination area on a mask R on which a pattern for transfer is formed, and a pattern image of the mask R on a photosensitive substrate W. Optical system 8 for projecting the mask R, and a mask stage RS for holding the mask R and scanning the mask R with respect to its illumination area
T and a substrate stage WS that holds the photosensitive substrate W and scans the photosensitive substrate W with respect to an area conjugate to a predetermined illumination area.
T. By scanning the photosensitive substrate W at a speed according to the projection magnification of the projection optical system 8 via the substrate stage WST in synchronization with scanning the mask R at a predetermined speed via the mask stage RST, the mask R Are sequentially projected and exposed on the photosensitive substrate W. Further, it has an imaging state correcting means (not shown) for correcting the imaging state of the projection optical system 8. The position of the mask stage RST is measured by mask-side position measuring means 15 and 16.
Above the mask R, a blowing means 12 for blowing gas to the mask R is provided, and a blowing port of the blowing means 12 has a longitudinal direction perpendicular to a direction in which the mask stage RST scans. For efficient air blowing. Further, the blowing means 12 is configured between the projection optical system 8 and the mask-side position measuring means 15 and 16 in the scanning direction, and the gas blown to the mask R whose temperature has increased increases the mask-side position measuring means 15 and The mask R can be cooled without affecting the 16 measurement optical paths such as air fluctuations.

In the illumination optical systems 1 to 5, the illumination light IL generated by the light source 1 passes through a shutter (not shown) and is then distributed by an illumination uniforming optical system 2 including a collimator lens 2a and a fly-eye lens 2b. Is converted into a substantially uniform light flux. Examples of the illumination light IL include excimer laser light such as KrF excimer laser light and ArF excimer laser light, harmonics of a copper vapor laser or a YAG laser, and ultraviolet bright lines (g-line, i-line, etc.) from an ultra-high pressure mercury lamp. Is used. When a laser light source is used, emission of light may be switched on and off by a power supply unit of the laser light source instead of the shutter. The illumination light emitted from the illuminance uniforming optical system 2 reaches a variable field stop 4 via a relay lens 3. The variable field stop 4 is disposed on a surface optically conjugate with the pattern formation surface of the mask R and the exposure surface of the wafer W,
The size (slit width, etc.) of the opening is adjusted by opening and closing a plurality of movable light shielding units (for example, two L-shaped movable light shielding plates) by, for example, a motor. The aperture operation is controlled by the variable field stop control unit 6, and the control unit 6
1 is controlled. By adjusting the size of the opening, the illumination area IAR for illuminating the mask R is set to a desired shape and size. The light beam passing through the variable field stop 4 illuminates, via a relay lens 5, a mask R on which a circuit pattern or the like is drawn.

The mask R is vacuum-sucked on a mask stage RST. The mask stage RST moves two-dimensionally in a plane perpendicular to the optical axis IX of the illumination optical system, and moves the mask R
Position. The mask stage RST is movable at a designated scanning speed in a predetermined direction (scanning direction) by a mask driving unit (not shown) constituted by a linear motor or the like. The mask stage RST has a movement stroke that allows the entire surface of the mask R to cross at least the optical axis IX of the illumination optical system. A moving mirror 15 for reflecting the laser beam from the interferometer 16 is fixed to an end of the mask stage RST.
The position of the ST in the scanning direction is always detected by the interferometer 16 with a resolution of, for example, about 0.01 μm. The position information of the mask stage RST from the interferometer 16 is sent to the stage control system 7, and the stage control system 7 drives the mask stage RST based on the position information of the mask stage RST. The stage control system 7 is controlled by the main control unit 11. The initial position of the mask stage RST is set at a predetermined reference position by a mask alignment system (not shown).
Is adjusted and determined so that the position of the mask R is accurately determined, so that the position of the mask R is measured with sufficiently high accuracy only by measuring the position of the movable mirror 15 with the interferometer 16.

The illumination light IL that has passed through the mask R enters, for example, a projection optical system 8 that is telecentric on both sides, and the projection optical system 8 changes the circuit pattern of the mask R to, for example, 1/6, 1 /.
A projection image reduced to 5 or 1/4 is formed on a wafer W having a surface coated with a photoresist (photosensitive material).
As shown in FIG. 2, in the projection exposure apparatus of the present embodiment, a rectangular (slit-shaped) illumination area I having a longitudinal direction perpendicular to the scanning direction (X direction) of the mask R.
The mask R is illuminated in the AR, and the mask R is scanned at a speed VR in the -X direction (or X direction) at the time of exposure. The center of the illumination area IAR substantially coincides with the optical axis IX, and is projected onto the wafer W via the projection optical system 8,
A slit-shaped exposure area IA (not shown) is formed. Since the wafer W has an inverted image relationship with the mask R, the wafer W is moved in the X direction (or -X direction) opposite to the direction of the speed VR.
Direction), scanning is performed at a speed VW in synchronization with the mask R, and the entire shot area on the wafer W can be exposed. The scanning speed ratio VW / VR is accurately determined by the projection optical system 8.
And the pattern in the pattern area of the mask R is accurately reduced and transferred onto the shot area on the wafer W. The width of the illumination region IAR in the longitudinal direction is set to be wider than the pattern region on the mask R and smaller than the maximum width of the light-shielding region, and the entire pattern region is illuminated by scan exposure. I have.

Referring back to FIG. 1, wafer W is vacuum-sucked on wafer holder 9, and wafer holder 9 is held on wafer stage WST. The wafer holder 9 can be tilted in an arbitrary direction with respect to the best image forming plane of the projection optical system 8 by the driving unit (not shown), can be finely moved in the optical axis IX direction (Z direction), and A rotation operation is also possible. On the other hand, wafer stage WST is configured to be movable not only in the above-described scan direction (X direction) but also in a direction (Y direction) perpendicular to the scan direction so as to be able to move arbitrarily to a plurality of shot areas. Then, a step-and-scan operation is performed in which the operation of scanning and exposing each shot area on the wafer W and the operation of moving to the next shot exposure start position are repeated. A wafer stage driving unit (not shown) such as a motor
Are driven in the XY directions. A movable mirror 17 for reflecting a laser beam from interferometer 18 is provided at an end of wafer stage WST.
Is fixed, and the position of the wafer stage WST in the XY plane is always detected by the interferometer 18 with a resolution of, for example, about 0.01 μm. The position information (or speed information) of wafer stage WST is sent to stage control system 10, and stage control system 10 controls wafer stage WST based on this position information (or speed information). The stage control system 10 is controlled by the main control unit 11. An off-axis alignment optical system 13 is arranged above wafer stage WST, and an alignment mark on wafer W is measured. The measurement result is subjected to image processing by the control unit 14 and supplied to the main control unit 11. The main controller 11 determines the position of the wafer W based on the position thus measured.
The arrangement of the upper shot area is calculated.

Above the mask stage RST, as described above, the blowing means 12 for blowing gas to the mask R.
As shown in FIG. 2, the air outlet of the air blowing means 12 has a shape in which the longitudinal direction is perpendicular to the scanning direction of the mask stage RST. Therefore, the scanning movement of the mask stage RST causes
The gas can be blown uniformly over the entire surface of the mask R. Note that, here, the blow port is formed in a box shape, but the same effect can be obtained by disposing a plurality of nozzle shapes in a direction orthogonal to the scanning direction of the mask stage RST instead. The blowing means 12 is a mask stage RST
Is disposed between the projection optical system 8 and the movable mirror 15 and the interferometer 16 with respect to the scanning direction. The air outlet of the air blowing means 12 is inclined and faces the projection optical system 8 side.
For this reason, the gas blown to the mask R whose temperature has risen is reflected by the mask R portion, and after the temperature has risen, it is opposite to the place where the moving mirror 15 and the interferometer 16 are arranged. And the optical path of the measurement light of the movable mirror 15 and the interferometer 16 is hardly affected.

FIG. 4 shows a projection exposure apparatus according to a second embodiment of the present invention. The same reference numerals are used for the same elements as those in FIG. The difference from the first embodiment is that two air outlets of the air blowing means for the mask R are provided. That is, the air blowing means is configured on both sides of the illumination area of the mask R, and the air blowing and the air blowing can be stopped or the air blowing and the suction can be switched in accordance with the scanning direction of the mask stage RST.
Thereby, even when the mask R scans in any direction, the relative speed between the mask R and the gas in contact with the surface of the mask R is made substantially constant, and the cooling efficiency of the mask R is improved.

More specifically, as shown in FIG.
Above the two air outlets 12a with the optical axis IX interposed therebetween.
And 12b are provided. 5 and 6 show the mask R portion. FIG. 5 shows the air outlets 12a and 1 of the air blowing means.
An example in which 2b is configured almost vertically is shown. FIG. 6 shows an example in which the air outlets 12a and 12b of the air blowing means are inclined and arranged toward the projection optical system 8 side. In any case, the arrangement can be made in a range that does not interfere with the illumination light beam.

In this configuration, the mask stage RST
When the scanning movement direction is the direction indicated by arrow a,
Air is blown from the nozzle 2a to the mask R, and is blown from the air outlet 12b to the mask R when the scanning direction is the arrow b.
At this time, the air outlet on the side that does not blow air is stopped.
Thus, the relative speed between the mask R and the gas in contact with the mask R is constant regardless of the scanning movement direction of the mask stage RST, and the cooling efficiency for the mask R can be constant.

It is more effective if the air outlet on the side that does not blow air is sucked or sucked instead of stopping the air blow. FIGS. 7 and 8 show third and fourth embodiments which embody this. In the example of FIG. 7, when the mask stage RST scans and moves in the direction of arrow a in the drawing, air is blown from the blower opening 12a and is sucked in by the blower opening 12b. From the air outlet 12a. In the example of FIG. 8, on the contrary, when the mask stage RST scans and moves in the direction of the arrow b, the blowing port 1a blows through the blowing port 12a.
2b. In this way, by inhaling the gas whose temperature has increased by the mask R by sucking the air through the air outlet on the side opposite to the air blowing side on the air blowing side, the influence on the measurement optical path of the moving mirror 15 and the interferometer 16 is prevented. be able to.

FIGS. 9 and 10 show fifth and sixth embodiments in which the moving mirror 15 and the interferometer 16 are similarly prevented from affecting the measurement optical path. In the example of FIG. 9, the whole of the two air outlets 12 a and 12 b is covered with the housing 21 to exhaust air. Thereby, even when there is a gas that cannot be sucked in at the air blowing port on the suction side, it is possible to more completely prevent the moving mirror 15 and the interferometer 16 from affecting the measurement optical path. On the other hand, FIG.
0 is between the optical axis IX and the movable mirror 15 and the interferometer 16 and is more than the movable mirrors 15a and 12b.
And an exhaust unit 22 provided on the interferometer 16 side.
Thereby, even when there is a gas that cannot be sucked in at the air blowing port on the suction side, it is possible to more completely prevent the moving mirror 15 and the interferometer 16 from affecting the measurement optical path.

In each of the above embodiments, the air cooling method for the mask R has been described. However, it is needless to say that the use of the correction method described in the section of the prior art is more effective.

<Embodiment of Device Manufacturing Method> Next, an embodiment of a device manufacturing method using the above-described exposure apparatus will be described. FIG. 11 shows a flow of manufacturing micro devices (semiconductor chips such as ICs and LSIs, liquid crystal panels, CCDs, thin-film magnetic heads, micromachines, etc.). Step 1
In (Circuit Design), a device pattern is designed. Step 2 is a process for making a mask on the basis of the designed pattern. On the other hand, in step 3 (wafer manufacture), a wafer is manufactured using a material such as silicon or glass. Step 4 (wafer process) is called a pre-process,
An actual circuit is formed on the wafer by lithography using the prepared mask and wafer. The next step 5 (assembly) is called a post-process, and is a process of forming a semiconductor chip using the wafer produced in step 4, and includes processes such as an assembly process (dicing and bonding) and a packaging process (chip encapsulation). including. In step 6 (inspection), inspections such as an operation confirmation test and a durability test of the semiconductor device manufactured in step 5 are performed. Through these steps, the semiconductor device is completed,
This is shipped (step 7).

FIG. 12 shows a detailed flow of the wafer process (step 4). Step 11 (oxidation) oxidizes the wafer's surface. Step 12 (CVD) forms an insulating film on the wafer surface. Step 13 (electrode formation) forms electrodes on the wafer by vapor deposition. In step 14 (ion implantation), ions are implanted into the wafer. In step 15 (resist processing), a resist is applied to the wafer. Step 16 (exposure) uses the above-described exposure apparatus to align the circuit pattern of the mask on a plurality of shot areas of the wafer and perform printing exposure. Step 17
In (development), the exposed wafer is developed. Step 18
In (etching), portions other than the developed resist image are scraped off. In step 19 (resist stripping), unnecessary resist after etching is removed. By repeating these steps, multiple circuit patterns are formed on the wafer.

By using the manufacturing method of this embodiment, it is possible to manufacture a large device which has been conventionally difficult to manufacture, with high accuracy.

[0042]

As described above, according to the present invention,
Since the air outlet having a shape extending in a direction substantially perpendicular to the scanning direction or a plurality of air outlets arranged in a direction substantially orthogonal to the scanning direction is provided, the air can be efficiently blown over the entire surface of the substrate to be scanned and moved. Is performed, and the thermal deformation of the original plate can be more effectively prevented or reduced. In addition, since the air outlet is disposed between the projection optical system and the interferometer, the original plate can be cooled without affecting the optical path measured by the interferometer due to air fluctuation or the like. In addition, according to the direction of the scanning movement, the air blowing from the first and second air blowing ports and the air blowing stop or suction can be switched for each air blowing port. Therefore, even when the original plate scans and moves in any direction, The relative speed between the original plate and the gas in contact with the surface of the original plate can be made substantially constant, and the cooling efficiency of the original plate can be improved. Further, since air is blown from the interferometer toward the optical axis of the projection optical system, the influence of the interferometer on the measurement optical path can be reduced. Since the exhaust means is provided between the air outlet and the interferometer, the influence of the interferometer on the measurement optical path can be reduced.

Therefore, it is possible to minimize the possibility that the original plate is thermally deformed by the irradiation energy with respect to the original plate and distortion of the projected image due to the thermal deformation is generated.

[Brief description of the drawings]

FIG. 1 is a diagram showing a schematic configuration of a scan exposure type projection exposure apparatus according to a first embodiment of the present invention.

FIG. 2 is a conceptual diagram of a mask unit in the apparatus of FIG.

FIG. 3 is an explanatory diagram of a mask section in an exposure apparatus according to a conventional example.

FIG. 4 is a configuration diagram of a projection exposure apparatus according to a second embodiment of the present invention.

FIG. 5 is a diagram showing an example of a mask unit in the apparatus of FIG.

FIG. 6 is a diagram showing another example of a mask unit in the apparatus of FIG.

FIG. 7 is a diagram showing a third embodiment of the present invention.

FIG. 8 is a diagram showing a fourth embodiment of the present invention.

FIG. 9 is a diagram showing a fifth embodiment of the present invention.

FIG. 10 is a diagram showing a sixth embodiment of the present invention.

FIG. 11 is a flowchart illustrating a device manufacturing method that can use the exposure apparatus of the present invention.

FIG. 12 is a detailed flowchart of a wafer process in FIG. 11;

[Explanation of symbols]

1: light source, 2: illuminance uniforming optical system, 2a: collimator lens, 2b: fly-eye lens, 3: relay lens,
4: Variable field stop, 5: Relay lens, 6: Variable field stop control unit, 7: Mask stage control unit, 8: Projection optical system, 9: Wafer holder, 10: Stage control system, 11:
Main control unit, 12: blowing means, 12a: blowing port, 12b:
Blow port, 13: Off-axis alignment optical system, 1
4: Control unit, 15: Interferometer reflection mirror, 16: Mask stage position detection interferometer, 17: Interferometer reflection mirror, 18: Mask stage position detection interferometer, 19: Blow port, 20: Anemometer , 21: housing, 22: exhaust unit, R: mask, RST: mask stage, W: wafer, WST: wafer stage, IL: illumination light, IX: illumination optical axis, IAR: illumination area, X: scanning direction.

Claims (11)

[Claims] 1. A scanning projection exposure apparatus for exposing a pattern of an original onto a substrate while scanning and moving the original and a substrate with respect to a projection optical system, wherein a blower blows toward the upper surface of the original during the scanning movement. A blowing means having a shape extending in a direction substantially perpendicular to the direction of the scanning movement or a plurality of blowing ports arranged in a direction substantially perpendicular to the direction of the scanning movement. A scanning projection exposure apparatus. 2. An original plate stage for performing scanning movement of an original plate, an interferometer for measuring the position of the original plate stage, a reflecting mirror fixed to the original plate stage, and blowing air toward an upper surface of the original plate. A scanning type for blowing air to the original plate and exposing the pattern of the original plate onto the substrate while scanning and moving the original plate and the substrate with respect to a projection optical system based on the measurement result of the position. The projection type exposure apparatus according to any one of claims 1 to 3, wherein the air outlet is disposed between the projection optical system and the interferometer. 3. The scanning projection exposure apparatus according to claim 1, wherein the blowing port is arranged so that a blowing direction is inclined with respect to an optical axis of the projection optical system. 4. A scanning projection exposure apparatus for exposing a pattern of an original plate onto the substrate while scanning and moving the original plate and the substrate with respect to a projection optical system, wherein air is blown toward the upper surface of the original plate during the scanning movement. Wherein the air blowing means comprises first and second air vents arranged on both sides of a predetermined illumination area on the original plate and in the direction of the scanning movement. Exposure equipment. 5. The air blowing means is capable of switching air blowing from the first and second air blowing ports and stopping or sucking air for each of the air blowing ports in accordance with a direction of the scanning movement. The scanning projection exposure apparatus according to claim 4, wherein 6. In the scanning movement, air is blown from one of the first and second air holes on the side of the original plate in the traveling direction, and the air hole on the opposite side stops air blowing or performs suction. 6. The scanning projection exposure apparatus according to claim 5, further comprising means for performing the switching. 7. The scanning projection exposure according to claim 4, further comprising a housing for covering the first and second air outlets, and a unit for exhausting the inside of the housing. apparatus. 8. An original plate stage for performing scanning movement of the original plate, an interferometer for measuring a position of the original plate stage, and a reflecting mirror fixed to the original plate stage, wherein the air outlet and the interferometer The scanning projection exposure apparatus according to claim 1, further comprising an exhaust unit between the scanning projection exposure apparatus and the scanning projection exposure apparatus. 9. An original plate stage for performing scanning movement of an original plate, an interferometer for measuring the position of the original plate stage, a reflecting mirror fixed to the original plate stage, and blowing air toward an upper surface of the original plate. A scanning type for blowing air to the original plate and exposing the pattern of the original plate onto the substrate while scanning and moving the original plate and the substrate with respect to a projection optical system based on the measurement result of the position. Wherein the blower is provided with a blower port to blow air from the interferometer toward the optical axis of the projection optical system when viewed in the direction of the scanning movement. Scanning projection exposure equipment. 10. An original plate stage for performing scanning movement of an original plate, an interferometer for measuring the position of the original plate stage, a reflecting mirror fixed to the original plate stage, and blowing air toward the upper surface of the original plate. A scanning type for blowing air to the original plate and exposing the pattern of the original plate onto the substrate while scanning and moving the original plate and the substrate with respect to a projection optical system based on the measurement result of the position. The projection type exposure apparatus according to any one of claims 1 to 3, further comprising exhaust means between the air outlet of the air blowing means and the interferometer. 11. A device manufacturing method, wherein a device is manufactured by using the scanning projection exposure apparatus according to any one of claims 1 to 10 and performing exposure while blowing air onto an upper surface of an original plate by an air blowing means. Method.