JP2000269114A - Illumination device, exposure device and exposure method - Google Patents

Abstract

(57) [Problem] To correct an illuminance distribution on a mask or a wafer to a desired distribution and independently change a pupil shape of illumination light with respect to each image height on a wafer. SOLUTION: A filter 14 is disposed at a position conjugate with an exit surface of a rod integrator using illumination light as a plurality of secondary light sources. When the aperture stop of the illumination light is small, the illumination light passing through the pattern 14A becomes dominant, and has a distribution in which the central part tends to be lower than the peripheral part, reflecting the transmittance of the pattern 14A. When the aperture stop of the illumination light is gradually increased, the pattern 14
As the illumination light passing through B increases, the influence of the transmittance distribution of the pattern 14B gradually increases. By arranging an appropriate pattern in the filter 14, it is possible to appropriately change the illuminance distribution on the wafer W according to the shape of the aperture stop of the illumination light.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an illuminating apparatus for forming a desired illuminance distribution by condensing light from a light source, and an exposure apparatus and method using the same. The present invention relates to an illuminating device and the like suitable for illuminating a mask for light exposure.

[0002]

2. Description of the Related Art Conventionally, in this type of illuminating device, a plurality of secondary light sources are formed by, for example, a rod-type optical integrator, and a mask on which a circuit pattern is drawn by using illumination light from these secondary light sources is used. Uniform illumination is provided. The illuminated circuit pattern is projected and exposed on a wafer coated with a photosensitive material via a projection lens.

Recently, the pupil shape of illumination light is changed by changing the shape of an aperture stop arranged at a conjugate position of a secondary light source in accordance with the shape of a pattern projected on a wafer. Attention has been focused on a technique for improving the resolution and depth of focus of a projection optical system of an exposure apparatus.

[0004]

In the above illuminating device, the illuminance distribution on the mask, that is, the illuminance distribution on the wafer when no pattern is formed on the mask, is generally considered to be uniform. However, if the illuminance distribution on the wafer is found to be non-uniform due to various factors such as dirt and eccentricity of the optical system and unevenness of the anti-reflection coating, the illuminance distribution is compensated for. If it can be adjusted, more precise exposure will be possible. Further, depending on the shape of the pattern on the mask, the aberration of the projection lens, the shape of the pupil of the illumination light, and the like, it may be better to intentionally provide a distribution of the illuminance on the wafer.

Similarly, the pupil shape of the illumination light is generally considered to be the same shape for each image height on the wafer. On the other hand, if the pupil shape is different, a better result may be obtained.

[0006]

Therefore, the present invention can correct the illuminance distribution on a mask or a wafer to a desired distribution, and can provide a pupil shape (coherence factor) of illumination light for each image height on the wafer. And an exposure apparatus and method using the same.

[0007]

In order to solve the above problems, an illumination device according to the present invention is formed by a rod-type optical integrator for forming a large number of light source images based on light from a light source, and a rod-type optical integrator. A relay optical system that condenses light from a number of light source images and illuminates the irradiated surface, and a light intensity distribution in a number of light source images that are placed on the light source side of a rod-type optical integrator independently of each other Lighting control means for controlling.

In the above-described illumination device, the illumination control means is arranged on the light source side of the rod-type optical integrator and independently controls the light intensity distribution in a large number of light source images. The state of the light to be emitted can be controlled simply and precisely. Therefore, the illumination state such as the illuminance distribution and the pupil shape on the irradiated surface can be adjusted to a desired state. Here, the light intensity distribution includes both changing the absolute amount of the intensity and changing the distribution state.

In a preferred embodiment, a condensing optical system for guiding light via the illumination control means to the rod-type optical integrator is disposed between the illumination control means and the rod-type optical integrator, and the illumination control means includes a plurality of illumination control means. Includes an optical filter that independently controls the transmittance distribution of light from the light source image, and the optical filter is substantially optically conjugate to the illuminated surface with respect to the condensing optical system, rod-type optical integrator, and relay optical system It is provided in a suitable position.

In the above-mentioned illumination device, the light distribution corresponding to a large number of light source images is individually adjusted by passing through the optical filter of the illumination control means, and the light is easily transmitted to the rod-type optical integrator by the condensing optical system. Since the light is individually incident, adjustment of the illumination state on the surface to be irradiated is simple.

An exposure apparatus according to the present invention includes a rod-type optical integrator that forms a large number of light source images based on light from a light source, and collects light from a large number of light source images formed by the rod-type optical integrator, respectively. The relay optical system that illuminates the mask, the projection system that projects the mask pattern on the photosensitive substrate, and the light intensity distribution of multiple light source images that are arranged on the light source side of the rod-type optical integrator independently of each other Lighting control means for controlling.

In the above-described exposure apparatus, the illumination control means is arranged on the light source side of the rod-type optical integrator and independently controls the light intensity distributions in a large number of light source images. The illumination state such as the shape can be adjusted to a desired state, and more precise and appropriate exposure suitable for the situation can be performed.

The exposure method according to the present invention uses a rod-type optical integrator that forms a large number of light source images based on light from a light source, and the light intensity distribution of the multiple light source images on the light source side of the rod-type optical integrator. A light control step of independently controlling the light intensity, a light intensity distribution of the light is independently controlled by the light control step, a light is condensed from a plurality of light sources, and the mask is illuminated. To a photosensitive substrate.

In the above-described exposure method, in the light control step, the light intensity distributions of a large number of light source images are independently controlled on the light source side of the rod-type optical integrator. And the like can be adjusted to a desired state, and more precise and context-sensitive exposure becomes possible.

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS [First Embodiment] FIG. 1 is a view for explaining the schematic arrangement of an exposure apparatus according to a first embodiment of the present invention.

First, an outline of an illumination optical system for illuminating the mask M will be briefly described. The illumination light from the light source 11 becomes almost parallel light through the beam shaping optical system 12, and
The light is reflected by the reflection mirror 13, and is guided to a rod-type optical integrator (hereinafter, an integrator) 16 through an illumination control device 20 which is an illumination control unit including a filter 14 and a condenser lens 15.

Light beams from a large number of secondary light sources formed by the integrator 16 are restricted by a variable field stop 17 and then by a relay optical system 18 to a mask stage M.
The image is projected onto the S mask M at a desired magnification and numerical aperture (NA). Thereby, the illumination area on the mask M is illuminated almost uniformly in a superimposed manner by the secondary light source. A reflection mirror 18c for bending the optical path is disposed between the front group 18a and the rear group 18b of the relay optical system 18, and the shape and size between the reflection mirror 18c and the rear group 18b are different. A turret plate 19 having a plurality of different openings is arranged. The turret plate 19, as a variable aperture means, appropriately adjusts the aperture shape at the pupil position of the illumination optical system.

The illumination light IL from the illumination optical system as described above
The image of the circuit pattern on the mask M illuminated by
The exposure light EL, which is the illumination light IL transmitted through the mask M, is reduced and projected onto the wafer W mounted on the wafer stage WS by the projection optical system 31, and the resist applied on the wafer W is exposed to light and the wafer is exposed. The circuit pattern image on the mask M is transferred onto W.

The details of each part of the exposure apparatus shown in FIG. 1 will be described below. The light source 11 constituting the illumination optical system includes illumination light IL having a wavelength sensitive to the resist applied to the wafer W.
Are emitted as substantially parallel light beams. Illumination light from the light source 11 is shaped into illumination light having a predetermined cross-sectional shape by the beam shaping optical system 12 and enters the illumination control device 20 via the reflection mirror 13. The illumination light may be, for example, a laser pulse.
It is adjusted by the trigger pulse sent from 0.

As will be described in detail later, the pre-filter 14 constituting the illumination control device 20 includes a plurality of filter elements provided corresponding to the number of secondary source images, and the mask M
That is, they are arranged near the conjugate plane S1 conjugate with the wafer W and perpendicular to the optical axis. The condenser lens 15 at the subsequent stage is provided with a virtual image plane S of the secondary light source formed by the integrator 16.
The illumination light IL, which is arranged at a focal distance from the position 2 and is substantially parallel to the optical axis from the filter 14, is once collected on the virtual image plane S2.

The filter 14 is connected to the controller 50
The optical path of the illumination optical system is driven according to conditions such as the pattern of the mask M to be transferred onto the wafer W by being driven by an actuator 41 controlled by the actuator 41. You can evacuate from inside.

The incident surface 16a of the integrator 16 is arranged near the virtual image plane S2. The illumination light IL condensed by the condenser lens 15 enters the integrator 16 from the incident surface 16a, is reflected by the inner surface of the integrator 16 a predetermined number of times, and exits from the exit surface 16b. The illumination light IL emitted from the integrator 16 is emitted from a virtual image of a discrete two-dimensional light source corresponding to the number of reflections as if it were emitted from the emission surface. For this reason, the angle of the illumination light emitted from the emission surface 16b is equal to 2
This corresponds to the emission angle of the illumination light IL from the virtual image of the next light source.

The turret plate 19 can adjust at least one of the shape and size of the secondary light source.
8a, a real image plane S3 on which a number of secondary light source images are formed
Is arranged in the vicinity of. The turret plate 19 is made of a transparent substrate made of quartz, and has a plurality of aperture stops 19 different in at least one of shape and size from each other as shown in FIG.
a to 19f are formed. Of these, the two aperture stops 19a and 19b having a circular aperture are used to change the σ value and the like, and the aperture stops 19c and 19d have an annular ratio (ratio between the inner diameter and the outer diameter of the annular opening). And the remaining aperture stops 19e and 19f have four eccentric apertures to form four eccentric secondary light sources.

The turret plate 19 is provided with a controller 50
Is appropriately rotated and driven by the motor 42 controlled by the controller, one aperture stop is selected according to the pattern of the mask M to be transferred onto the wafer W, and is arranged on the optical path of the illumination light IL.

Here, the mask M is provided between the emission surface 16 of the integrator 16 and the relay optical system 18 as described above.
It is arranged at a position substantially conjugate with respect to b, and as a result, it is also arranged at a position substantially conjugate with respect to the filter 14.
The wafer W is arranged at a conjugate position of the mask M via the projection optical system 31.

The wafer stage WS includes a position detecting device 61 such as a laser interferometer for monitoring the movement of the movable mirror 60 provided on the wafer stage WS, and an alignment optical system for enabling alignment between the wafer W and the mask M. 62
Are provided. A driving device 65 that drives the wafer stage WS three-dimensionally is controlled by the controller 50, and includes a position detection device 61 and an alignment optical system 6
The wafer stage WS is driven to a desired position on the basis of the output of Step 2.

The wafer stage WS is provided with an illuminance sensor 67 for measuring the illuminance of illumination light and the pupil shape. The illuminance sensor 67 has a pinhole 67a as shown in FIG.
1, an upper plate 67b disposed at the height of the imaging plane, a lens 67c disposed at a position apart from the pinhole 67a by a focal length, and a lens 67c disposed at a position away from the pinhole 67a.
And a CCD 67d for detecting through the CCD. By appropriately moving the wafer stage WS and moving the illuminance sensor 67 directly below the projection optical system 31, a diffraction pattern according to the periodic pattern on the mask M is projected on the CCD 67d.
By analyzing the output of the CCD 67d and comparing it with data stored in advance, the pattern on the mask M can be specified to some extent, and the type of the mask M on the mask stage MS can also be determined. Further, if the mask M is removed from the mask stage MS, the wafer stage WS is appropriately moved, and the illuminance sensor 67 is moved within the range of the exposure area of the projection optical system 31, the illuminance at each point on the wafer W can be adjusted. The projected light amount is projected on the CCD 67d. That is, by detecting how the sum of the outputs of the CCD 67d changes according to the image height of the wafer W, the illuminance distribution on the wafer W can be obtained. Further, a brightness distribution according to the pupil shape of each point on the wafer W is formed on the CCD 67d. That is, the output distribution of the CCD 67d is
Is detected according to the image height of the wafer W
The pupil shape at each of the above image heights can also be detected.

The data and commands necessary for the operation of the exposure apparatus shown in FIG. 1, ie, the operation of the controller 50, can be input from the outside via the input device 55.

FIG. 4 is an enlarged view for explaining the structure of the filter 14 arranged near the conjugate plane S1. On the surface of the filter 14, a rectangular filter pattern 14A,
14B are arranged. Each filter pattern 14A,
14B has a specific transmittance distribution, and the filter pattern 14A on the center side and the filter pattern 14B on the peripheral side have different transmittance distribution characteristics. In the drawing, for understanding,
The symbol A is attached to the position of the former filter pattern 14A,
The position of the latter filter pattern 14B is denoted by the symbol B to clarify the arrangement of the two filter patterns 14A and 14B. Each of the filter patterns 14A and 14B corresponds to each of the plurality of secondary light sources formed by the integrator 16.

FIG. 5 shows each filter pattern 14 of FIG.
FIG. 3 is a diagram schematically illustrating the relationship between the shapes and arrangements of A and 14B and a plurality of secondary light sources formed by an integrator 16. FIG. 5A shows an optical path of illumination light emitted from the filter 14 in parallel with the optical axis, and FIG. 5B shows an optical path of illumination light emitted from one point on the filter 14.

The filter pattern 140 on the optical axis disposed on the filter 14 controls the intensity distribution of the light flux from the secondary light source 100 that is not reflected on the inner surface of the integrator 16. Further, a pair of filter patterns 141a and 141b adjacent to both outer sides of the filter pattern 140 are provided.
Controls the intensity distribution of the luminous flux from the secondary light source images 101a and 101b reflected once on the inner surface of the integrator 16. Further, the filter patterns 141a, 141
b, a pair of filter patterns 142 adjacent to both outer sides
Reference numerals a and 142b control the intensity distribution of light fluxes from the secondary light source images 102a and 102b reflected twice on the inner surface of the integrator 16. According to such a configuration, it is possible to independently control the transmittance of each of the plurality of secondary light sources formed by the integrator 16.

These filter patterns 140, 141
a, 141b, 142a, 142b are arranged near the surface S1 conjugate with the exit surface 16b of the rod-type integrator 16, and the magnification of the condenser lens 15 is smaller than the size of the exit surface 16b of the integrator 16. This corresponds to the ratio of the size of each filter pattern 140 to 142b of the filter 14. Therefore, the shape of one filter pattern corresponds to the illumination area on the mask M or the wafer W in FIG.
The transmittance distribution of 142b is reflected on the illuminance distribution of the illumination area on the wafer W.

FIG. 5 conceptually illustrates the shape and arrangement of the filter patterns. The arrangement density of the filter patterns is lower than that of the embodiment shown in FIG.
In this case, the filter pattern 140 corresponds to the filter pattern 14A in FIG. 4 from the viewpoint of being disposed on the center side, and the filter patterns 142a and 142b correspond to the filter pattern 14B in FIG. 4 from the viewpoint of being disposed on the peripheral side. Can be thought of.

Returning to the description of FIG.
The period for arranging 4A and 14B is set as follows. That is, the magnification from the exit surface 16b of the integrator 16 to the conjugate plane S1 is β, and the exit surface 16b
Assuming that there is no distortion between the conjugate plane S1 and the rod cross section of the integrator 16 (Lx, Ly), the period of each filter pattern 14A, 14B is (βLx, βLy). However, if there is a distortion between the emission surface 16b and the conjugate surface S1, the arrangement of the filter patterns does not always have a fixed period. In this case, since it is necessary to arrange the filter pattern at a position corresponding to the secondary light source corresponding to each filter pattern, it is necessary to correct the pattern arrangement according to the amount of distortion. At this time, since the shape of the filter pattern is also affected by distortion, it is necessary to change the shape according to the position where the pattern is arranged. Therefore, when the optical system is configured so that there is no distortion between the emission surface 16b and the conjugate surface S1, the shape and arrangement of the filter pattern can be determined by the paraxial magnification β between the emission surface 16b and the conjugate surface S1, This is preferable from the viewpoint of facilitating the design of the filter pattern.

The filter 14 includes, for example, Cr, Ni, A
A fine dot pattern of a metal thin film such as 1 is drawn, and the transmittance distribution of each of the filter patterns 14A and 14B is controlled by changing the density of the dot pattern. The transmittance of the metal thin film itself is not limited to 0%. If it is desired to increase the transmittance of the filter patterns 14A and 14B, the transmittance of the metal thin film itself may be increased. In the case where the transmittance distribution is controlled by the density of the dot pattern as in the former case, if the filter patterns 14A and 14B are precisely arranged on the surface S1 conjugate with the emission surface 16b of the integrator 16, the emission surface 16b and the wafer W Is conjugate, the shape of the dot itself in the dot pattern may be transferred onto the wafer W. For this reason,
In the present embodiment, the transfer of the dots themselves is prevented by arranging the filter patterns 14A and 14B at positions slightly defocused from the conjugate plane S1 of the emission surface 16b. However, for the purpose of preventing the image of the dust from being transferred to the wafer W when dust adheres to the emission surface 16b, the emission surface 16b is intentionally removed from the conjugate surface of the wafer W. In such a case, the filter patterns 14A and 14B may be arranged so as to be exactly conjugate with the emission surface 16b of the integrator 16. In other words, the filter pattern 14
A and 14B are not completely conjugate to the wafer W,
What is necessary is just to arrange so that it may be located in the vicinity. On the other hand, when the transmittance of the filter patterns 14A and 14B is controlled not by the dot pattern but by the thickness of a metal thin film or a dielectric film, for example, the filter patterns 14A and 14B are controlled.
There is no problem even if B is arranged at a position conjugate with the wafer W. If the size of the dot pattern formed on the filter patterns 14A and 14B is too large, the dot pattern may be transferred onto the wafer W. On the other hand, if the size is too small, the diffraction angle due to the dot pattern increases and the efficiency is reduced. There is a problem. From the above circumstances, the size of the dot pattern is appropriately in the range of 1 μm to 100 μm.

FIG. 6 shows the filter pattern 14 shown in FIG.
An example of the transmittance distribution of A and 14B is shown. FIG. 6 (a)
FIG. 6 shows the transmittance distribution of the filter pattern 14A.
(B) shows the transmittance distribution of the filter pattern 14B. A dot pattern or the like is formed on the filter pattern 14A disposed on the center side of the filter 14 such that the transmittance at the center is higher than that at the periphery (see FIG. 6A).
In the filter pattern 14B disposed on the peripheral side of the filter 14, a dot pattern or the like is formed such that the transmittance at the center is lower than that at the peripheral part (see FIG. 6B).

When the pattern arrangement as shown in FIGS. 4 and 6 is adopted, when the diameter of the aperture stop of the illumination light IL is small (for example, the aperture stop 19a in the turret plate 19 of FIG. 1).
Is on the optical path), the illumination light passing through the filter pattern 14A becomes dominant, and the illuminance on the wafer W reflects the transmittance of the filter pattern A, and the illuminance on the wafer W The distribution tends to be low in the center. Further, when the aperture stop diameter of the illumination light IL is gradually increased (for example, when the aperture stop 19b is on the optical path in the turret plate 19 in FIG. 1), the illumination light passing through the filter pattern 14B increases. Thus, the influence of the transmittance distribution of the filter pattern 14B gradually increases, that is, as the diameter of the aperture stop arranged at the optical path position of the turret plate 19 increases, the illuminance on the wafer W tends to be higher at the peripheral portion than at the central portion. Conversely, as the diameter of the aperture stop becomes smaller, the illuminance on the wafer W tends to be higher at the center than at the periphery, which is achieved by the pattern arrangement in the filter 14 as described above. This means that the illuminance distribution on the wafer W can be appropriately changed according to the diameter of the light aperture stop.

If this is used conversely, even if the illuminance distribution on the wafer W differs depending on the shape of the aperture stop due to some cause such as transmittance unevenness of the illumination optical system, etc. Thus, an illuminance distribution that does not depend on the shape of the aperture stop can be achieved by canceling the illuminance distribution. In other words, by arranging an appropriate filter pattern on the filter 14 for compensating for the change in the illuminance distribution on the wafer W due to the change of the aperture stop, the phenomenon that the illuminance distribution on the wafer W differs depending on the shape of the aperture stop. It becomes possible to cancel. In this way, by actively controlling the illuminance distribution when the shape of the aperture stop is changed, it is possible to configure an illumination optical system or the like in which the illuminance distribution does not change even when the shape of the aperture stop is changed, The transfer accuracy of the fine pattern can be improved.

When the illuminance distribution is positively controlled as described above, not only the single filter 14 is moved into and out of the optical path of the illumination optical system according to conditions such as the pattern of the mask M, but also the filter pattern is different. A plurality of types of filters are prepared, and these filters are appropriately replaced according to the change in the illuminance distribution on the wafer W, the type of the pattern of the mask M, and the like. At this time, the type of the mask M detected by using the illuminance sensor 67, the illuminance distribution on the wafer W, and the distribution of the pupil shape can be used as criteria for filter replacement.

In the first embodiment described above, the turret plate 19
Because the aperture stops 19a to 19f are switched by the rotation of, even if the number of aperture stops is increased, the diameter of the aperture stop of the illumination light IL changes discontinuously. By using a stop that continuously changes the diameter of the aperture instead of the turret plate 19, the diameter of the aperture stop of the illumination light IL can be continuously changed.

[Second Embodiment] The exposure apparatus of the second embodiment is a modification of the first embodiment. The structure of the entire exposure apparatus is the same as that shown in FIG.

In the case of the second embodiment, the pupil shape of the illumination light at each image height on the wafer W is controlled independently for each image height. Here, the image height does not mean a narrow meaning of the distance from the optical axis, but means a two-dimensional coordinate on the surface of the wafer W.

The device of the second embodiment also uses the same filter 14 as shown in FIG. However, as the filter pattern 140 at the center, a pattern such that the transmittance at the center is higher than that at the periphery as shown in FIG.
As the peripheral filter patterns 142a and 142b, a pattern such that the transmittance at the center is lower than that at the peripheral portion as shown in FIG.
It is assumed that a pattern having a uniform transmittance is applied to 41a and 141b. In this case, the filter patterns 140, 1
41a, 141b, 142a, 142b are each 2
Next light source 100, 101a, 101b, 102a, 102
The intensity distribution of the light beam from b is controlled.

FIG. 7 shows the illuminance distribution on the wafer W.
On the wafer W, the filter patterns 140, 141a,
Illuminance distributions corresponding to 141b, 142a, 142b are superimposed. At this time, at the center position C on the wafer W, the light from the secondary light source 100 is
On the other hand, at positions P1 and P2 distant from the center of the wafer W, the light from the secondary light sources 100a and 102b is more strongly observed than the light from the secondary light sources 102a and 102b.
It is observed weaker than the light from. However, each secondary light source 1
The illuminance distribution obtained by adding the illumination light supplied from 00, 101a, 101b, 102a, and 102b onto the wafer W is substantially uniform.

On the other hand, when viewed from the center C on the wafer W,
As shown in FIG. 8A, the intensity of the secondary light source image at the central part on the pupil coordinate parallel to the optical axis is such that the intensity of the secondary light source image at the peripheral part on the pupil coordinate forms a large angle with the optical axis. It becomes stronger than the strength of. When viewed from the periphery P1 and P2 on the wafer W,
As shown in FIG. 8B, the intensity of the secondary light source image at the peripheral portion forming a large angle with respect to the optical axis is equal to the intensity at the central portion parallel to the optical axis.
It becomes stronger than the intensity of the next light source image. Utilizing such a phenomenon, it is possible to positively control the pupil shape such that an arbitrary secondary light source distribution is formed at an arbitrary point on the wafer W by disposing an appropriate filter pattern on the filter 14. Becomes That is, the shape (coherence factor) of the secondary light source at an arbitrary image height on the wafer W surface
Can be controlled independently for each image height, and the transfer accuracy of a fine pattern can be improved.

[Third Embodiment] The exposure apparatus of the third embodiment is a modification of the first embodiment. The structure of the entire exposure apparatus is the same as that shown in FIG.

In the example shown in FIG. 6 of the first embodiment, the case where the filter pattern is rotationally symmetric is shown. However, the present invention is not limited to this, and a filter pattern having a rotationally asymmetric distribution may be used. it can. When such a filter pattern is used, an arbitrary illuminance distribution can be formed at an arbitrary two-dimensional point on the wafer W.

FIG. 8 shows a filter 3 according to the third embodiment.
It is a figure explaining the arrangement method of 14 filter patterns 314F and 314R. In the rod-type integrator 16, since the light flux from the adjacent secondary light source is inverted, the third
Filter pattern 3 of filter 314 as in the embodiment
In the case where 14F and 314R are rotationally asymmetric, it is preferable that adjacent filter patterns are arranged so as to be mirror images of each other as shown in the figure. The filters 314F, 314R
The characters F and R described in the positions of
Means that there are two types of transmittance distributions on the center side and outside, and the rotational position of the letters F and R means the direction of asymmetry.

As described above, the present invention has been described with reference to the embodiments. However, the present invention is not limited to the above embodiments.
For example, in the above embodiment, as the rod-type optical integrator, the integrator 16 having a rectangular cross section is used, but the cross-sectional shape is not limited to this, and an integrator having another cross-sectional shape such as a hexagon is used. be able to. In this case, filter 1
It is preferable that each of the filter patterns 4 and the like be similar to the cross-sectional shape of the rod-type optical integrator from the viewpoint of efficient use of illumination light.

[0050]

In the above-mentioned illumination apparatus, the illumination control means is arranged on the light source side of the rod-type optical integrator and independently controls the light intensity distribution in a large number of light source images. The state of the light supplied to the device can be easily and precisely controlled. Therefore, the illumination state such as the illuminance distribution and the pupil shape on the irradiated surface can be adjusted to a desired state.

[Brief description of the drawings]

FIG. 1 is a schematic diagram illustrating a structure of an exposure apparatus according to a first embodiment.

FIG. 2 is a diagram illustrating a turret plate for replacing an aperture stop of an illumination optical system.

FIG. 3 is a sectional structural view for explaining an apparatus for detecting an illuminance distribution.

FIG. 4 is a diagram for explaining a structure of a filter constituting an illumination control unit.

FIG. 5 is a diagram schematically illustrating a relationship between a filter pattern and a secondary light source.

FIGS. 6A and 6B are diagrams illustrating two types of filter patterns provided on a filter. FIGS.

FIG. 7 is a graph showing an illuminance distribution on a wafer in the case of the second embodiment.

FIG. 8 is a graph illustrating a pupil shape of the illumination light of FIG. 7;

FIG. 9 is a diagram illustrating a filter pattern arrangement method according to a third embodiment.

[Explanation of symbols]

Reference Signs List 3 illumination control means 11 light source 14,314 filter 14A, 14B filter pattern 15 condenser lens 16 integrator 16a incident surface 16b emission surface 19 turret plate 19a-19f aperture stop 31 projection optical system 41 actuator 42 motor 50 controller 55 input device 65 drive Apparatus 67 Illuminance sensor 100, 101a, 101b, 102a, 102b Secondary light source 140, 141a, 141b, 142a, 142b Filter pattern M Mask S1 Conjugate plane S2 Virtual image plane S3 Real image plane W Wafer

Claims (4)

[Claims] 1. A rod-type optical integrator that forms a large number of light source images based on light from a light source, and collects light from the large number of light source images formed by the rod-type optical integrator to irradiate light. A lighting system comprising: a relay optical system that illuminates a surface; and illumination control means that is arranged on the light source side of the rod-type optical integrator and independently controls the intensity distribution of light in the multiple light source images. apparatus. 2. A light-collecting optical system that guides light passing through the illumination control means to the rod-type optical integrator is disposed between the illumination control means and the rod-type optical integrator. An optical filter that independently controls transmittance distribution of light from a large number of light source images, wherein the optical filter is substantially the same as the illuminated surface with respect to the condensing optical system, the rod-type optical integrator, and the relay optical system. The lighting device according to claim 1, wherein the lighting device is provided at an optically conjugate position. 3. A rod-type optical integrator that forms a large number of light source images based on light from a light source, and collects light from the large number of light source images formed by the rod-type optical integrator to form a mask. A relay optical system for illuminating, a projection system for projecting the pattern of the mask onto a photosensitive substrate, and a light intensity distribution in the multiple light source images, which are arranged on a light source side of the rod-type optical integrator, independently of each other. An exposure apparatus, comprising: illumination control means for controlling. 4. Using a rod-type optical integrator that forms a large number of light source images based on light from a light source,
A light control step of independently controlling the intensity distribution of light in a plurality of light source images on the light source side of the rod-type optical integrator; and the plurality of light sources in which the light intensity distribution is independently controlled by the light control step. From the light from each,
An exposure method comprising: illuminating a mask; and exposing a photosensitive substrate with a pattern of the mask.