KR20090107982A - Exposure apparatus and device manufacturing method - Google Patents

Abstract

PURPOSE: An exposure apparatus is provided to reduce a noise generated by a light reflected by a light absorption layer. CONSTITUTION: An exposure apparatus(100) includes a lighting optical system(120) and a projection optical system(160). The lighting optical system lights a reflective type mask(150) through a light from a light source(110). The projection optical system projects an image of a pattern provided to the reflective type mask to a substrate. The lighting optical system includes a first lighting region decision unit, a second lighting region decision unit, and a light collecting mirror. The first lighting region decision unit determines a lighting region of the reflective type mask having a pattern to be projected on the substrate. The second lighting region decision unit determines a lighting region in which a measuring pattern used for wavefront aberration of the projection optical system is lighted.

Description

Exposure apparatus and device manufacturing method {EXPOSURE APPARATUS AND DEVICE MANUFACTURING METHOD}

The present invention generally relates to an exposure apparatus and a device manufacturing method.

Semiconductor devices and the like are fabricated photolithographically. Photolithography is performed using an exposure apparatus that projects a pattern on a disc (mask or reticle) onto a substrate (wafer) through a projection optical system.

In particular, in recent years, exposure apparatuses using extreme ultraviolet (EUV) light whose wavelength is about one tenth of ultraviolet rays used in conventional exposure apparatuses have been developed to form finer line widths of device patterns. The wavelength λ of the EUV light is in the range of about 10 nm to 15 nm (eg 13.5 nm). Since EUV light having such a wavelength is absorbed a lot by a material, a refractive optical system cannot be used as the projection optical system. Instead, reflective optics are used. The wave front aberration of the projection optical system needs to be λ / 14 (= 0.96 nm) rms or less according to the Marechal's criterion of the material. In order to realize such precise aberration measurement of the projection optical system in the exposure apparatus, there is a need for a high precision measurement technique capable of resolving much smaller aberration, that is, about one tenth of the wavefront aberration of the projection optical system.

Exemplary interferometers capable of measuring the wavefront of the projection optical system with high accuracy include a lateral shearing interferometer (Japanese Patent Laid-Open No. 2005-159213, Japanese Patent Laid-Open No. 2006-332586 and Japanese Patent) See Publication No. 2006-303370).

In measurement using a shearing interferometer, a pinhole mask having a pinhole is disposed on the object plane of the projection optical system (test optical system). If the pinhole is small enough, the wavefront of the light output from the pinhole is considered an ideal spherical wave and thus used as a reference wavefront. The image of the pinhole is affected by the aberration of the test optical system only before it is imaged on the image plane. The diffraction grating is arranged in the vicinity of the upper surface. The diffraction grating shears the wavefront in two directions perpendicular to each other. This forms interference fringes on the observation surface disposed downstream of the upper surface and the diffraction grating. The wavefront aberration of the test optical system can be measured by integrating wavefront information acquired from wavefront data in each direction and reconstructing into two-dimensional wavefront data.

In order to measure the aberration of the projection optical system included in the exposure apparatus with high accuracy, it is preferable to use the illumination optical system and the light source actually used for exposing the substrate. When using an exposure light source (a laser excitation plasma (LPP) light source or a discharge excitation plasma (DPP) light source, etc.), since the luminance (illuminance, or luminous flux per unit area) of the exposure light source is low, Roughness is considered low. In this regard, Japanese Patent Laid-Open No. 2006-332586 discloses a technique for improving light utilization efficiency by arranging a plurality of pinholes. On the other hand, Japanese Laid-Open Patent Publication No. 2006-303370 discloses a technique for improving luminance by exchanging mirrors of an illumination optical system.

Even in the techniques disclosed in Japanese Patent Laid-Open Nos. 2006-332586 and 2006-303370, it is difficult to selectively collect light in the pinhole because the directivity of the light from the exposure light source is low. When light is irradiated to the light absorbing layer of the pinhole mask-the region excluding the pinhole-due to a very small amount of reflected light from the light absorbing layer, an appropriate signal-to-noise (S / N) ratio used for measurement cannot be obtained. Therefore, the interference fringes contain high noise, and the wavefront aberration of the optical system under test cannot be measured with high accuracy. This is because the area of the illumination area of the light absorbing layer of the pinhole mask used for aberration measurement is large relative to the area of the pinhole.

This invention provides the exposure apparatus which can measure the wave front aberration of a test optical system with high precision.

According to one aspect of the present invention, an exposure apparatus includes an illumination optical system configured to illuminate a reflective mask using light from a light source and a projection optical system configured to project an image of a pattern provided on the reflective mask onto a substrate. The illumination optics is first illumination area defining means configured to define an illumination area of a reflective mask having a pattern to be projected onto a substrate, a second configured to define an illumination area to which a metrology pattern used to measure wavefront aberration of the projection optics is illuminated. Illumination area defining means, wherein the second illumination area defining means is removable with respect to the optical path of the illumination optical system, and condenses the light from the first illumination area defining means to the pattern to be projected onto the substrate, and from the second illumination area defining means. And a focusing mirror configured to focus light onto the metrology pattern. The illumination region defined by the second illumination region defining means is smaller than the illumination region defined by the first illumination region defining means.

Other features and aspects of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings, wherein like reference numerals designate the same or alternatively similar parts throughout the drawings.

Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings.

Hereinafter, the exposure apparatus 100 according to the first embodiment of the present invention will be described with reference to FIGS. 1 and 2. The exposure apparatus 100 includes at least an illumination optical system 120, a mask stage, a projection optical system 160, and a wafer stage 190. FIG. 1 shows an exposure apparatus in a state in which a reflective mask 150 having a circuit pattern to be projected onto a wafer 180 is illuminated to project a pattern onto the wafer 180 through a projection optical system (test optical system) 160 ( 100). 2 illustrates the exposure apparatus 100 in a state in which wavefront aberration of the projection optical system 160 is measured.

Referring to FIG. 1, light emitted from the EUV exposure light source 110 is incident on the illumination optical system 120, which is a reflection optical system. The illumination optical system 120 includes a reflection mirror 130, a reflective integrator 131, an exposure field stop 141 as the first illumination area defined aperture, and a field of view aperture for measurement as the second illumination area defined aperture ( 140 and other reflective optics elements.

The illumination optical system 120 forms an intermediate image forming surface for forming light from the light source 110. One of the exposure field stop 141 and the measurement field stop 140 for switching which are mutually switchable are arrange | positioned at the intermediate | middle imaging surface. Alternatively, both the exposure field stop 141 and the measurement field stop 140 are disposed on the intermediate image plane. The intermediate image plane is disposed at a position conjugate with the object plane of the projection optical system 160. When both the exposure field stop 141 and the measurement field stop 140 are disposed on the intermediate image plane, the intermediate image plane includes a peripheral area around it.

The reflective mirror 130 and the reflective integrator 131 may be disposed in the optical path of the illumination optical system 120 at any one of the two near the plane which is conjugate with the pupil plane of the projection optical system 160. Can be switched with each other.

The reflective integrator 131 reflects EUV light emitted from the light source 110 to form a plurality of secondary light sources. Some of the rays from the secondary light sources are blocked by the exposure field stop 141, so that the illumination region of the mask 150 is defined as an arcuate shape. Referring to FIG. 3, the exposure field stop 141 is a light blocking member (light shielding plate) having an arc-shaped opening 1410. Therefore, referring to FIG. 4, an arc type defined by the exposure field stop 141 of the circuit pattern 302 disposed on the mask 150 disposed on the object plane (irradiation surface) of the projection optical system 160. Illuminated area 301 is illuminated. The exposure field stop 141 may be detachable with respect to the optical path of the illumination optical system 120.

The condensing mirrors disposed downstream of the illumination optical system 120 with respect to the exposure field stop 141 are output from the reflective integrator 131, and the light beams passing through the exposure field stop 141 are transferred to the mask 150. The light is collected on the circuit pattern 302. Thus, the circuit pattern 302 is illuminated.

As reflected above, the light reflected (diffracted) by the illuminated mask 150 is incident on the projection optics 160. The projection optical system 160 projects the image of the pattern 302 of the mask 150 onto the photosensitive agent applied to the wafer 180 by projection exposure at a predetermined magnification. The projection optical system 160 is a reflective optical system, but is not limited thereto. The same applies to the illumination optical system 120.

Illumination of the mask 150 and exposure of the wafer 180 are performed while scanningly moving the mask stage holding the mask 150 and the wafer stage 190 holding the wafer 180 synchronously.

Referring to FIG. 1, when the wafer 180 is exposed to light, the measurement field stop 140 moves from the optical path of the illumination optical system 120 to the measurement field stop 140 in the illumination optical system 120. Retreat to the position which does not block the light. In this case, the reflective mirror 130 is also disposed outside the optical path of the illumination optical system 120. That is, the measurement field stop 140, the reflective integrator 131, and the reflective mirror 130 can be inserted into and removed from the optical path of the illumination optical system 120. The measurement field stop 140 is detachable with respect to the optical path of the illumination optical system 120 on the surface that is conjugate with the object plane of the projection optical system 160.

2, the state of the exposure apparatus 100 in the case of measuring the wave front aberration of the projection optical system 160 is demonstrated. As can be seen in FIG. 2, when measuring the wave front aberration of the projection optical system 160, the measurement field stop 140 and the reflection mirror 130 are disposed in the optical path of the illumination optical system 120. In addition, the measurement mask 400 is disposed on the object plane of the projection optical system 160, and the wavefront aberration measurement unit 170 is disposed on the exposure area on the upper surface (the surface of the wafer 180) of the projection optical system 160. . This switching of the optical elements can be implemented by using known drive mechanisms.

When measuring the wave front aberration, the measurement field stop 140 blocks a part of the light traveling through the illumination optical system 120 to block the illumination area of the measurement mask 400 disposed on the object plane of the projection optical system 160. define. The condensing mirrors disposed downstream of the illumination optical system 120 with respect to the field of view aperture 140 for measurement condense the light passing through the field of view aperture 140 to the pattern (measurement pattern) used for wavefront aberration measurement. do.

Reflective mirror 130, which is a planar mirror or a curved mirror, reflects light from light source 110 without scattering. Therefore, when the reflective mirror 130 is inserted into the optical path instead of the reflective integrator 131, the illumination area in the object plane of the projection optical system 160 is an area when the field stops are not disposed in the intermediate image plane. Switching from 301 to the area 501 shown in FIG. Therefore, the brightness of the light illuminating the irradiated surface is increased.

In general, light rays output from different positions in the illuminated area 301 upon exposure form different aberrations due to the difference in the height (image height) of the object with respect to the optical axis of the projection optical system 160. In consideration of this, the measurement mask 400, which is the reflective mask illustrated in FIG. 6, is disposed on the object plane of the projection optical system 160 instead of the mask 150. The measurement mask 400 has a plurality of measurement patterns 403 (403a to 403i) used for measurement of wavefront aberration of the projection optical system 160. The area of the measurement mask 400 except for the measurement patterns 403 is covered with the light absorbing layer 402. The metrology patterns 403 are arranged at predetermined heights of the object in the illuminated area 301 upon exposure. 6 illustrates nine measurement patterns 403a to 403i, the number of measurement patterns 403 is not limited thereto and may vary depending on the number of positions to be measured.

7 is a schematic enlarged view of one of the metrology patterns 403. The metrology pattern 403 includes a plurality of pinhole groups 802, each of which includes a plurality of reflective pinholes 801. Referring to FIG. 7, the minimum circle (circumscribed circle) 404 including all the pinhole groups 802 has a diameter E of 200 μm. This means that the pinhole groups 802 are disposed within a diameter of 200 μm. 8 is a cross-sectional view of the measurement pattern 403 and its peripheral region. The metrology pattern 403 includes a reflective layer 901 and a light absorbing layer 803 adjacent to the reflective layer 901 on a substrate made of Si or glass (not shown). The reflective layer 901 is a multilayer film containing a Mo layer and a Si layer. The light absorbing layer 803 absorbs EUV light. Since the light absorbing layer 803 is necessary for efficiently absorbing EUV light, the light absorbing layer 803 is preferably made of TaBN, Ta, Cr or Ni. If the light absorbing layer 803 is made of TaBN, the light absorbing layer 803 needs to have a thickness of 100 nm or more.

In order to measure the wavefront aberrations of the projection optics 160 independently of each other at the heights of the different objects, referring to FIGS. 6 and 7, the illumination region 501 may include any metrology patterns 403 (eg, It is necessary to define the lighting area 401 to illuminate 403a. For this reason, the measurement field stop 140 for defining the illumination area is disposed in the optical path near the intermediate image plane of the illumination optical system 120. 9 shows the measurement field stop 140. The light passing through the opening (pinhole) 1401 of the measurement field stop 140 is prescribed to illuminate the region 401 of the measurement mask 400 disposed on the object plane of the projection optical system 160, and the measurement is performed. The pattern 403a and the surrounding area around it are illuminated. The area of the opening (pinhole) 1401 disposed in the measurement field stop 140 is smaller than the area of the opening 1410 disposed in the exposure field stop 141. This means that the illumination area 401 defined by the measurement field stop 140 is smaller than the illumination area 301 defined by the exposure field stop 141.

If the illumination region 401 is large with respect to the measurement pattern 403, the ratio of the weakly reflected light from the light absorbing layer 803 increases, and noise is generated when the wave front aberration is measured. Therefore, the size of the opening 1401 of the measurement field stop 140 is determined so that the size of the illumination region 401 becomes substantially the same as the size of the measurement pattern 403. Thus, the illumination area 401 may be precisely tailored to the metrology pattern 403.

For example, if the section of the illumination optical system 120 from the intermediate imaging surface to the irradiated surface produces a magnification M, the diameter of the illumination region 401 is equal to the diameter D of the opening 1401 of the measurement field stop 140. It is calculated by multiplying the magnification M. When the diameter of the smallest circle 404 including the measurement pattern 403 (pinhole groups 802) is denoted by E, when D = E / M is set to satisfy, the size and measurement pattern of the illumination area 401 The size of 403 may be equivalent.

The diameter E of the minimum circle 404 including each metrology pattern 403 is a value that produces a substantially uniform aberration after the light rays from the metrology patterns 403 pass through the projection optical system 160. It needs to be limited to. Specifically, this situation can be realized by setting the diameter E to a value from about 100 μm to 1 mm.

The light reflected by the measurement patterns 403 is incident on the projection optical system 160, is affected by the wave front aberration of the projection optical system 160, and is imaged on the image plane of the projection optical system 160.

In the first embodiment of the present invention, the wavefront aberration measurement unit 170 includes a two-dimensional diffraction grating and a detector such as a charge-coupled device. The diffraction grating splits the light passing through the projection optics 160 into two terms orthogonal to the optical axis (center of light). Exemplary methods for measuring wavefront aberration using the aforementioned elements are disclosed in International Publication No. WO2006 / 115292 A1, published under Japanese Patent Publication No. 2006-332586 and Patent Cooperation Treaty (PCT), Each is incorporated herein by reference in its entirety.

The two-dimensional diffraction grating, which serves as a light splitting means, divides the light from the projection optical system 160 into a plurality of diffraction lights, thereby generating a plurality of converging points on the image plane of the projection optical system 160. In order to obtain a high contrast interference pattern, the spacing between the two-dimensional diffraction grating and the top surface is determined so that a Talbot effect can be produced. The detector images shearing interference fringes generated by light from a two-dimensional diffraction grating. Data on the interference fringes picked up by the detector is transmitted to the computing unit. The calculation unit analyzes (restores) the wavefront and calculates the wavefront aberration of the test optical system, that is, the projection optical system 160. The wavefront yields, for example, differential wavefronts in two respective orthogonal directions defined by the diffraction grating, integrates the differential wavefronts in the two respective directions, and synthesizes the wavefronts. It is interpreted by combining.

Next, the interference stripes to be imaged will be described. The pinhole groups 802 are arranged such that the signal strength of the interference fringes generated by the light passing through the projection optical system 160 is large. Specifically, the arrangement of the pinhole groups 802 is caused by the stripes having the maximum intensity among the interference fringes generated by the light from one of the pinhole groups 802 and the light from the other pinhole group 802. Of the generated interference fringes, the stripes having the maximum intensity are designed to overlap each other.

The reflectance of the light absorbing layer 803 is not zero, that is, the light absorbing layer 803 reflects a small amount of light. Thus, as the amount of light reflected by the light absorbing layer 803 increases, the contrast of the interference fringes decreases. For example, it is assumed that the diameter E of the minimum circle 404 including the measurement pattern 403 is 200 µm, and the reflectance of the light absorbing layer composed of TaBN is 0.3%. In this case, if the diameter A (see FIG. 7) of the illuminated region 401 at the time of wavefront aberration measurement is also 200 μm, the contrast of the interference stripes is 0.47. The diameter A is preferably 200 μm, which coincides with the diameter of the region in which the pinhole groups 802 are arranged. However, the diameter A can be widened due to the aberration of the illumination optics 120.

10 is a graph showing the relationship between the diameter A of the illumination area 401 and the contrast of the interference stripes. The graph shows that the contrast of the interference fringes decreases as the diameter A increases. The contrast of the interference stripes depends not only on the diameter A but also on the surface roughness of the optical elements included in the illumination optics 120 and the reflectance of the light absorbing layer 803. Thus, if a decrease in contrast of about 0.05 due to an increase in diameter A is acceptable, diameter A may increase up to about 300 μm. This means that when the diameter A increases due to the aberration of the illumination optical system 120, the aberration needs to be defined so that the enlargement of the condensing spot having a diameter of 200 mu m is a diameter of about 300 mu m or less.

In order to measure wavefront aberrations of the projection optics 160 at different image heights, the illumination area 401 needs to be movable to illuminate any metrology patterns 403 at the desired image height.

As shown in FIG. 5, after the illumination region 501 is defined by the reflection mirror 130 and the wavefront aberration at the height of the image corresponding to the measurement pattern 403a is measured, it corresponds to the measurement pattern 403b. Consider the case of measuring the wave front aberration at the height of the phase. In this case, the measurement field stop 140 is moved into the intermediate image plane by using a mechanism configured to move the measurement field stop 140 to apply light to the measurement pattern 403b. During the above-described processing, the position of the measurement mask 400 is fixed. Subsequently, the wavefront aberration of the projection optical system 160 at the height of the image corresponding to the measurement pattern 403b is measured by using the light reflected by the measurement pattern 403b.

Next, the case where the wave front aberration at the height of the image corresponding to the measurement pattern 403i is measured is described. In this case, the reflection mirror 130 is rotated by a mechanism configured to rotate (move) the reflection mirror 130 to change the direction of the light reflected by the reflection mirror 130. Specifically, the reflective mirror 130 can be rotated at any angle with an axis extending to the surface including the center (optical axis) of light functioning as the rotation axis. Therefore, the illumination area 501 is moved to illuminate the area including the measurement pattern 403i. After the rotation of the reflection mirror 130 or in synchronization with the rotation of the reflection mirror 130, in the intermediate image formation surface, the light passing through the opening 1401 of the field of view aperture 140 is applied to the measurement pattern 403i. Move the field of view aperture 140 for measurement. Subsequently, the wavefront aberration of the projection optical system 160 at the height of the image corresponding to the measurement pattern 403i is measured by using the light reflected by the measurement pattern 403i. In this way, wavefront aberration of the projection optical system 160 at a given image height can be measured.

The measurement pattern 403 of the first embodiment of the present invention is disposed in the measurement mask 400 provided separately from the mask 150, but the measurement pattern 403 is not limited thereto. For example, the metrology pattern 403 may alternatively be disposed in the mask 150, whereby the metrology mask 400 and the mask 150 are integrated.

According to the first embodiment of the present invention, since the noise generated by the light reflected by the light absorbing layer can be reduced, the wave front aberration of the test optical system can be measured with high accuracy.

Next, a second embodiment of the present invention will be described. The second embodiment is different from the first embodiment in a mechanism configured to move the measurement field stop and the measurement field stop. The description of the same or similar elements as the elements of the first embodiment is omitted.

11 shows a measurement field stop 142 according to a second embodiment of the present invention. The measurement field stop 142 is a light shielding plate in which a plurality of openings (pinholes) 1421 to 1425 are disposed. The number of openings depends on the number of positions you want to measure. The openings are configured such that only one opening is disposed in an area corresponding to the arc-shaped opening 1410 of the exposure field stop 141 for exposure.

Each of the openings 1421 to 1425 of the measurement field stop 142 has a smaller area than the opening 1410 disposed in the exposure field stop 141. This means that the illumination area 401 defined by any openings 1421-1425 of the metrology field stop 142 is smaller than the illumination area 301 defined by the exposure field stop 141.

Referring to FIG. 12, the following describes a method of measuring wavefront aberrations at different phase heights. Fig. 12 is a view of the exposure field stop 141 and the measurement field stop 142 disposed on the intermediate image plane as viewed from the direction of incidence of light. First, the measurement field stop 142 is moved by using a moving mechanism to arrange the opening 1421 in the area illuminated by the opening 1410 and the reflection mirror 130 of the exposure field stop 141 for exposure. Further, the reflection mirror 130 is appropriately rotated (moved) by using a rotation (movement) mechanism so as to apply the light reflected by the reflection mirror 130 to the area corresponding to the height of the image to be measured.

Light passing through the opening 1421 is applied to one of the measurement patterns 403 at the position of the object plane corresponding to the opening 1421. In this state, the wavefront aberration of the projection optical system 160 at the position (image height) described above is measured.

Using the mechanism configured to move the field of view aperture 142 in the directions shown by both arrows 602 in FIG. 12, moving the field of view aperture 142 in the left direction of FIG. The wavefront aberration of the projection optics 160 can be measured at any locations defined by different image heights in the directions of 602.

Accordingly, the measurement field stop 142 is moved in the proper direction of both arrows 602 such that the opening 1422 is disposed in the opening 1410 of the exposure field stop 141. Subsequently, as described above, the light passing through the opening 1422 is used to measure the wave front aberration of the projection optical system 160 at the height of the image corresponding to the opening 1422.

Likewise, the wavefront aberration of the projection optical system 160 can be measured at the heights of the respective images corresponding to the openings 1423 to 1425 by using the above-described moving mechanism.

According to the second embodiment of the present invention, since the measurement field stop 142 only needs to move in one axis direction, a mechanism for moving the measurement field stop 142 is more than in the first embodiment. Can be simplified.

As described above, the number, arrangement, shape, and the like of the opening of the measurement field stop 142 are arbitrarily determined according to the number of positions to be measured, desired precision, and the like. Further, the shape of the openings may be arbitrarily determined by configuring the viewing field stop 142 of the plurality of movable light blocking plates.

Hereinafter, another embodiment of the present invention will be described. This embodiment relates to a method of manufacturing a device (semiconductor integrated circuit (IC) device, liquid crystal display device, etc.) by using the above-described exposure apparatus 100. The device uses the exposure apparatus 100 to project an image of a pattern disposed on the original plate (mask or reticle) by exposing a substrate (wafer, glass plate, etc.) to which the photosensitive agent is applied, and developing the substrate (photosensitive agent). And other known steps such as etching, resist stripping, dicing, bonding, packaging and the like. According to the device manufacturing method of this embodiment, a device having a higher quality than the known devices can be manufactured.

Although the present invention has been described with reference to exemplary embodiments, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all modifications and equivalent structures and functions.

It is to be understood that the invention is not limited to the specific embodiments other than those defined in the claims, as many different embodiments of the invention can be made clearly and broadly without departing from the spirit and scope of the invention. .

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, help explain the principles of the invention.

1 shows an exposure apparatus in a state in which a wafer is exposed to light.

2 shows an exposure apparatus in a state of measuring wavefront aberration.

3 shows an exposure-use field stop.

4 shows the area of the illuminated mask when the wafer is exposed to light.

5 shows the area of the illuminated mask when using a reflective mirror.

6 shows a measurement mask used when measuring wavefront aberration.

7 is an enlarged view of a measurement pattern.

8 is a cross-sectional view of the measurement pattern and its peripheral region.

Fig. 9 shows a measuring field stop according to the first embodiment of the present invention.

10 is a graph showing the relationship between the illumination area of a metrology mask and the contrast of interference fringes.

Fig. 11 shows a measuring field stop according to a second embodiment of the present invention.

12 shows the mechanism of the field of view aperture for measurement according to the second embodiment of the present invention.

<Explanation of symbols for the main parts of the drawings>

100: exposure apparatus

110: exposure light source

120: illumination optical system

130: reflective mirror

131: reflective integrator

140: field of view aperture for measurement

141: field of view aperture for exposure

150: mask

160: projection optical system

170: wavefront aberration measurement unit

180: wafer

Claims (13)

Illumination optics configured to illuminate the reflective mask using light from the light source; And Projection optics configured to project an image of a pattern provided on the reflective mask onto a substrate Including, The illumination optical system, First illumination region defining means configured to define an illumination region of the reflective mask having a pattern to be projected onto the substrate; Second illumination region defining means configured to define an illumination region in which the measurement pattern used to measure the wavefront aberration of the projection optical system is illuminated, the second illumination region defining means being removable with respect to the optical path of the illumination optical system; And A condensing mirror configured to condense the light from the first illumination region defining means into a pattern to be projected onto the substrate and to condense the light from the second illumination region defining means into the measurement pattern Including; And an illumination region defined by said second illumination region defining means is smaller than an illumination region defined by said first illumination region defining means. The method of claim 1, And said second illumination region defining means is a light blocking member having a pinhole. The method of claim 1, And the second illumination region defining means is a light blocking member having a plurality of openings. The method of claim 1, And the first and second illumination region defining means are arranged in an intermediate image plane provided to the illumination optical system. The method of claim 4, wherein And a moving mechanism configured to move the second illumination region defining means within the intermediate image plane. The method of claim 1, The measurement pattern includes a plurality of pinhole groups. The method of claim 1, And the measurement pattern is provided to the reflective mask. The method of claim 1, And the measurement pattern is provided to a reflective mask other than the reflective mask having a pattern to be projected onto the substrate. The method of claim 1, Light splitting means configured to split light output from the measurement pattern and passing through the projection optical system; A detector configured to detect interference fringes produced by the light divided by the light splitting means; And An arithmetic unit configured to acquire wavefront aberration of the projection optical system from data of interference fringes detected by the detector Exposure apparatus further comprising. The method of claim 1, A reflective integrator configured to generate a plurality of secondary light sources by receiving light from the light source; And Plane mirror More, One of the switchable integrator and the planar mirror is disposed on a surface conjugated with a pupil plane of the projection optical system, When the first illumination region defining means is disposed in the optical path, the reflective integrator is disposed in the optical path, And the planar mirror is disposed in the optical path when the second illumination region defining means is disposed in the optical path. The method of claim 10, A moving mechanism configured to move the second lighting area defining means; And Rotating means configured to rotate the planar mirror And the second illumination region defining means and the planar mirror are moved and rotated by driving the moving mechanism and the rotating means, respectively. The method of claim 1, The size of the opening provided in the second illumination region defining means is denoted by D, and the magnification formed by the section of the illumination optical system guiding the light from the second illumination region defining means to the object plane of the projection optical system is represented by M. The exposure apparatus which displays and satisfy | fills the relationship of D = E / M, when E represents the diameter of the smallest circle containing the said measurement pattern. Exposing the substrate using an exposure apparatus according to any one of claims 1 to 12; Developing the exposed substrate; And Forming a device from the developed substrate Device manufacturing method comprising a.

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