JP2023148840A - Illumination optical system, exposure device and article production method - Google Patents

Abstract

To provide a technology advantageous for forming a desired light intensity distribution on a pupil plane of an illumination optical system.SOLUTION: An illumination optical system uses a luminous flux from a light source to form a light intensity distribution on a pupil plane, and illuminates an object with the light from the pupil plane. The illumination optical system has a first region, a second region, and a third region having different diffraction effects, the first region is arranged so as to surround the second region and the third region, and a diffractive optical element that forms the light intensity distribution on the pupil plane and a control unit that is arranged between the light source and the diffractive optical element, and controls a ratio of a light amount that illuminates the second region and the light amount that illuminates the third region by partially shielding or attenuating the luminous flux from the light source.SELECTED DRAWING: Figure 5A

Description

The present invention relates to an illumination optical system, an exposure apparatus, and an article manufacturing method.

Modified illumination (annular illumination, dipole illumination, quadrupole illumination, etc.) is used as the illumination condition in the exposure equipment that exposes the substrate by projecting the pattern of the original onto the substrate using the projection optical system while illuminating the original with the illumination optical system. can be used. Under various illumination conditions, the effective light source distribution, which is the light intensity distribution in the pupil plane of the illumination optical system, influences the performance of the image formed on the substrate during exposure. For example, if there is asymmetry between the vertical and horizontal directions in the effective light source distribution (hereinafter referred to as effective light source HV difference), when forming a vertical pattern and a horizontal pattern, A line width difference may occur between the pattern and the horizontal pattern. Therefore, it is necessary to reduce the effective light source HV difference. As a method for adjusting asymmetry such as the effective light source HV difference, Patent Document 1 and Patent Document 2 describe the use of a diffractive optical element having a plurality of diffraction regions having different diffraction effects. However, these documents do not describe disposing a member that blocks or attenuates part of the light beam between the diffractive optical element and the light source and driving the member.

JP2008-91881A Special Publication No. 2013-501348

An object of the present invention is to provide an advantageous technique for forming a desired light intensity distribution on the pupil plane of an illumination optical system.

One aspect of the present invention relates to an illumination optical system that forms a light intensity distribution on a pupil plane using a luminous flux from a light source and illuminates an object with the light from the pupil plane, and the illumination optical system uses diffraction light from each other. It has a first region, a second region, and a third region having different effects, the first region is arranged so as to surround the second region and the third region, and forms the light intensity distribution on the pupil plane. a diffractive optical element, which is disposed between the light source and the diffractive optical element, and blocks or attenuates a part of the light flux from the light source, thereby determining the amount of light that illuminates the second area and the third area; and an adjustment unit that adjusts the ratio of the amount of light illuminated.

According to the present invention, an advantageous technique for forming a desired light intensity distribution on a pupil plane of an illumination optical system is provided.

FIG. 1 is a diagram schematically showing the configuration of an exposure apparatus and an illumination optical system according to a first embodiment. FIG. 1 is a diagram illustrating the configuration of a diffractive optical element according to a first embodiment. FIG. 3 is a diagram illustrating a light intensity distribution formed on the Fourier transform surface of the illumination optical system by the diffractive optical elements of the first and second embodiments. FIG. 2 is a diagram schematically showing a configuration example of an adjustment unit according to the first embodiment. FIG. 4 is a diagram for explaining the operation of the adjustment unit of the first embodiment. FIG. 4 is a diagram for explaining the operation of the adjustment unit of the first embodiment. FIG. 4 is a diagram for explaining the operation of the adjustment unit of the first embodiment. FIG. 4 is a diagram for explaining the operation of the adjustment unit of the first embodiment. FIG. 7 is a diagram illustrating the configuration of a diffractive optical element according to a second embodiment. FIG. 7 is a diagram for explaining the operation of the adjustment unit of the second embodiment. FIG. 7 is a diagram for explaining the operation of the adjustment unit of the second embodiment. FIG. 7 is a diagram for explaining the operation of the adjustment unit of the second embodiment. FIG. 7 is a diagram for explaining the operation of the adjustment unit of the second embodiment. FIG. 7 is a diagram for explaining the operation of the adjustment unit of the second embodiment.

Hereinafter, embodiments will be described in detail with reference to the accompanying drawings. Note that the following embodiments do not limit the claimed invention. Although a plurality of features are described in the embodiments, not all of these features are essential to the invention, and the plurality of features may be arbitrarily combined. Furthermore, in the accompanying drawings, the same or similar components are designated by the same reference numerals, and redundant description will be omitted.

FIG. 1 schematically shows the configuration of an exposure apparatus 100 and an illumination optical system IL of the first embodiment. The exposure apparatus 100 includes a light source 1 that generates a light beam for exposure, an illumination optical system IL that illuminates an original M, a projection optical system PO that projects a pattern of the original M onto a substrate W, and an illumination optical system IL and a projection optical system. A control unit CNT may be provided to control the system PO. The exposure apparatus 100 may be configured to expose the substrate W by projecting the pattern of the original M onto the substrate W using the projection optical system PO. In one example, the exposure apparatus 100 may be configured as a scanning exposure apparatus that transfers the pattern of the original M onto the substrate W by exposing the substrate W while relatively scanning the original M and the substrate W. Typically, the substrate W has a plurality of shot areas, and exposure of the substrate W is performed for each of the plurality of shot areas. The original M is, for example, a mask or a reticle, and the substrate W is, for example, a wafer or a glass plate.

In the following explanation, the direction parallel to the optical axis (optical path) between the projection optical system PO and the substrate W (the normal direction to the substrate W) is defined as the Z direction, and two directions perpendicular to each other in a plane perpendicular to the Z direction are defined as the Z direction. The two directions are the X direction and the Y direction. In the projection optical system PO and/or the illumination optical system IL, the optical axis (light beam) may be bent, and in such a case, the optical axis direction at each location is the Z direction, and two directions orthogonal to the Z direction are defined. are the X direction and the Y direction.

The control unit CNT is, for example, a PLD (Programmable Logic Device) such as FPGA (Field Programmable Gate Array), or an ASIC (Application Specific Integrated). Abbreviation for Circuit), or a general-purpose computer with a built-in program or a dedicated computer, or a combination of all or part of these.

The light source 1 emits a luminous flux or light for exposing the substrate W. The illumination optical system IL uses the light beam from the light source 1 to form a light intensity distribution on the pupil plane PP, and illuminates the original M or the object with the light from the pupil plane PP. The illumination optical system IL may include, for example, a routing optical system 2, an optical element 6, a diffractive optical element 7, a condenser lens 8, and a prism unit 10. Further, the illumination optical system IL may further include, for example, a zoom lens unit 11, a multi-beam forming section 12, an aperture 13, and a condenser lens 14. The routing optical system 2 is provided between the light source 1 and the optical element 6 and guides the light beam emitted from the light source 1 to the optical element 6. In one example, the illumination optical system IL further includes a mirror 3 and a plane-parallel plate 4, and the light beam emitted from the routing optical system 2 is reflected by the mirror 3 and enters the illumination optical system IL via the plane-parallel plate 4. I can do it. The position and angle of the light beam incident on the optical element 6 can be adjusted by the mirror 3 and the parallel plane plate 4.

The illumination optical system IL may further include an adjustment unit 5. The adjustment unit 5 may be configured to change the distribution of the light flux incident on the diffractive optical element 7 by blocking or attenuating part of the light flux. The adjustment unit 5 is arranged immediately before or after the optical element 6.

The optical element 6 is an optical element for making the angle of the light beam incident on the diffractive optical element 7 uniform within the incident plane of the diffractive optical element 7, and can be placed on the optical path of the diffractive optical element 7 on the light source side. The optical element 6 can include an optical integrator such as a microlens array, a fiber bundle, or a fly's eye lens, and guides the light beam from the light source 1 to the diffractive optical element 7 while keeping its divergence angle constant. This reduces the influence of output fluctuations of the light source 1 on the light intensity distribution formed by the diffractive optical element 7 on the pupil plane PP of the illumination optical system IL.

The diffractive optical element 7 is arranged on the optical path between the optical element 6 and the condenser lens 8 , and diffracts the light beam from the optical element 6 and guides it to the condenser lens 8 . The diffractive optical element 7 forms a desired light intensity distribution using the light beam from the light source 1 on the pupil plane PP of the illumination optical system IL, which is a plane conjugate with the pupil plane of the projection optical system PO, and on a plane conjugate with the pupil plane PP. do. The light intensity distribution thus formed on the pupil plane PP of the projection optical system PO is called an effective light source distribution. The diffractive optical element 7 may be, for example, a computer generated hologram (CGH) designed using a computer so that a desired diffraction pattern can be obtained on the diffraction pattern surface.

The illumination optical system IL may be provided with a plurality of diffractive optical elements 7, and the plurality of diffractive optical elements 7 may be arranged in a plurality of slots of a turret (not shown), respectively. The plurality of diffractive optical elements 7 can form mutually different effective light source distributions on the pupil plane PP of the illumination optical system IL. These effective light source distributions can have, for example, the shapes of small circles (relatively small circles), great circles (relatively large circles), annular, dipole, quadrupole shapes. A method of illuminating the original M with an effective light source distribution having a shape such as an annular zone, a dipole, or a quadrupole is called modified illumination.

The condenser lens 8 is disposed on the optical path between the diffractive optical element 7 and the prism unit 10, condenses the light beam diffracted by the diffractive optical element 7, and forms a diffraction pattern on the Fourier transform surface 9. The Fourier transform surface 9 is a surface that is in an optical Fourier transform relationship with the diffractive optical element 7 between the multi-beam forming section 12 (optical integrator) and the diffractive optical element 7. Therefore, by exchanging (changing) the diffractive optical element 7, the shape of the diffraction pattern formed on the Fourier transform surface 9 can be changed.

The prism unit 10 and the zoom lens unit 11 are arranged on the optical path between the Fourier transform surface 9 and the multi-beam forming unit 12 (optical integrator), and are zoom optics that expand the light intensity distribution formed on the Fourier transform surface 9. It functions as a system. The prism unit 10 can guide the diffraction pattern (light intensity distribution) formed on the Fourier transform surface 9 to the zoom lens unit 11 by adjusting the annular ratio and the like. Further, the zoom lens unit 11 is disposed on the optical path between the prism unit 10 and the multi-beam forming section 12, and may include a first lens and a second lens. The zoom lens unit 11 adjusts the σ value of the diffraction pattern formed on the Fourier transform surface 9 based on the ratio of the NA (numerical aperture) of the illumination optical system IL and the NA (numerical aperture) of the projection optical system PO. The light beam can be guided to the multi-beam forming section 12 at the same time.

The multi-beam forming unit 12 is provided on the optical path between the zoom lens unit 11 and the condenser lens 14, and generates a large number of secondary light sources according to the diffraction pattern whose annular ratio, aperture angle, and σ value have been adjusted. formed and guided to the condenser lens 14. The multi-beam forming unit 12 may include a fly's eye lens as an optical integrator, but may also include other optical integrators such as an optical pipe, a diffractive optical element, or a microlens array instead of or in addition to the fly's eye lens. good. By providing the multi-beam forming section 12, the original M, which is a non-illuminated surface, can be uniformly illuminated with the light beam that has passed through the diffractive optical element 7. Further, an aperture 13 is provided between the multi-beam forming section 12 and the condenser lens 14. The aperture 13 is arranged on the pupil plane PP of the illumination optical system IL. The condenser lens 14 is provided between the multi-beam forming section 12 and the original M. As a result, the original M is illuminated in a superimposed manner by a large number of light beams guided from the multi-beam forming section 12.

The original M is provided between the condenser lens 14 and the projection optical system PO, and has a device pattern to be transferred onto the substrate W. The original M is held by an original stage (not shown) driven by an original driving mechanism (not shown). The projection optical system PO is provided between the original M and the substrate W, and maintains the original M and the substrate W in an optically conjugate relationship. The substrate W is held by a substrate stage (not shown) driven by a substrate drive mechanism (not shown). The resolution of the pattern of the original M projected onto the substrate W depends on the effective light source distribution, and by forming an appropriate effective light source distribution, the resolution of the pattern can be improved.

Here, a case where the light intensity distribution formed on the Fourier transform surface 9 by the diffractive optical element 7 has an annular shape will be described as an example. FIG. 2 shows an example of the configuration of the diffractive optical element 7. The diffractive optical element 7 may include a first region 71, a second region 72, and a third region 73 having different diffraction effects. The first region 71 may be arranged to surround the second region 72 and the third region 73. The second region 72 and the third region 73 are divided vertically in FIG. 2, and the area of the second region 72 and the area of the third region 73 are equal to each other. The light intensity distributions formed on the Fourier transform surface 9 by each of the first region 71, the second region 72, and the third region 73 are different from each other.

The light intensity distribution formed on the Fourier transform surface 9 by the first region 71 may have an annular shape 91 illustrated in FIG. 3(a). The light intensity distribution formed on the Fourier transform surface 9 by each of the second region 72 and the third region 73 is as shown in the Y-direction dipole 92 illustrated in FIG. 3(b) and the Y-direction dipole 92 illustrated in FIG. 3(c), respectively. It may be an X direction dipole 93. The second region 72 can be understood as including a diffractive element forming at least two poles arranged in the pupil plane in a first direction (for example in the X direction) and separated from each other. The third region 73 can be understood as including a diffraction element that forms at least two poles that are separated from each other in a second direction (for example, the Y direction) orthogonal to the first direction in the pupil plane PP. In addition, although the example in which the diffractive optical element 7 has the first area 71, the second area 72, and the third area 73 has been described here, the diffractive optical element 7 may have four or more areas.

The illumination area 74 illustrated in FIG. 2 is an area where the diffractive optical element 7 is illuminated. The second region 72 and the third region 73 are arranged inside the illumination region 74. The light intensity distribution formed on the Fourier transform surface 9 by each of the second region 72 and the third region 73 has a shape in which the Y-direction dipole 92 and the X-direction dipole 93 are added, and the light intensity distribution is annular. Almost equal to shape 91. Therefore, when the illumination area 74 is illuminated, the areas included in the illumination area 74 (part of the first area 71, the entire second area 72, and the entire third area 73) are formed on the Fourier transform surface 9. The light intensity distribution has an annular shape similar to the annular shape 91. The Fourier transform plane 9 may be considered to be conjugate with the pupil plane of the illumination optical system IL. The following description will be made assuming that the light intensity distribution formed on the Fourier transform plane 9 is equivalent to the light intensity distribution (effective light source distribution) formed on the pupil plane PP.

FIG. 4 schematically shows an example of the configuration of the adjustment unit 5. The adjustment unit 5 may include a shaft 51 , a shielding member 52 coupled to the shaft 51 , and a drive mechanism 53 that drives the shielding member 52 by driving the shaft 51 . The axis 51 may be arranged to extend in a direction intersecting (for example, orthogonal to) the optical path of the light beam from the light source 1 to the diffractive optical element 7 . The shaft 51 may be understood as a support member that supports the shielding member 52. The shielding member 52 blocks or attenuates a part of the light beam from the light source 1. The shielding member 52 may have a rectangular shape, for example. For example, the axis 51 may be arranged parallel to the boundary line between the second region 72 and the third region 73 of the diffractive optical element 7. The shaft 51 (as a result, the shielding member 52) is driven by the drive mechanism 53, for example, around a central axis extending in a direction intersecting the optical path of the light beam from the light source 1 to the diffractive optical element 7. ). The driving of the shaft 51 (and consequently the shielding member 52) by the driving mechanism 53 may include, for example, translational driving of the shaft 51 in a direction intersecting the optical path of the light beam from the light source 1 to the diffractive optical element 7. The shaft 51 may be replaced by a support member, such as a transparent plate, by which the shielding member 52 may be supported.

5A to 5C illustrate an example of a region of the entire diffractive optical element 7 that is shielded by the adjustment unit 5. As illustrated in FIG. 5A, when the shielding member 52 is perpendicular to the optical axis of the adjustment unit 5 and directly facing the second region 72, a shadow region 75a of the shielding member 52 is formed in the second region 72 of the diffractive optical element 7. . Note that although a shadow of the axis 51 is also formed on the diffractive optical element 7, this is small and its influence is ignored. The second area 72 includes a shadow area 75a and a non-shadow area 72a other than the shadow area 75a. The non-shadow area 72a has a smaller area than the original second area 72. Since the shadow area 75a is not formed in the third area 73, the area of the illuminated third area 73 does not change. Therefore, the ratio of the amount of light that illuminates the second region 72 and the amount of light that illuminates the third region 73 changes, and the amount of light that illuminates the third region 73 becomes relatively large. By illuminating the area excluding the shadow area 75a from the illumination area 74, the light intensity distribution formed on the Fourier transform surface 9 corresponds to a double pole in the X direction, as shown in the distribution 94a illustrated in FIG. 5A. The strength of the portion corresponding to the Y-direction dipole is stronger than the strength of the portion corresponding to the Y-direction dipole. If the sign of the effective light source HV difference when the intensity of the X-direction dipole is stronger than the Y-direction dipole is defined as +, then the distribution 94a shows that the effective light source HV difference is +.

As illustrated in FIG. 5B, when the shielding member 52 is tilted from the direction perpendicular to the optical axis of the adjustment unit 5 and directly faces the second region 72, the shielding member 52 is attached to the second region 72 of the diffractive optical element 7. A shadow area 75a is created. The second area 72 includes a shadow area 75a and a non-shadow area 72a other than the shadow area 75a. The non-shadow area 72a has a smaller area than the original second area 72. Since the shadow area 75a is not formed in the third area 73, the area of the illuminated third area 73 does not change. By illuminating the area excluding the shadow area 75a from the illumination area 74, the light intensity distribution formed on the Fourier transform surface 9 has a ring shape like the distribution 94b illustrated in FIG. 5B. The effective light source HV difference in the distribution 94b is smaller than the distribution 94a and larger than the annular shape 91.

As illustrated in FIG. 5C, when the shielding member 52 is perpendicular to the optical axis of the adjustment unit 5 and directly facing the third region 73, a shadow region 75c of the shielding member 52 is formed in the third region 73 of the diffractive optical element 7. . The third area 73 includes a shadow area 75c and a non-shadow area 73c other than the shadow area 75c. The non-shadow area 73c has a smaller area than the original third area 73. Since the shadow area 75c is not formed in the second area 72, the area of the illuminated second area 72 does not change. At this time, the distribution formed on the Fourier transform surface 9 has a ring shape like the distribution 94c illustrated in FIG. 5C. The effective light source HV difference in the distribution 94c becomes -.

By rotating the shielding member 52 (in other words, the shaft 51) by the drive mechanism 53, the shadow area formed on the diffractive optical element 7 changes, and the amount of light illuminating the second area 72 and the amount of light illuminating the third area 73 change. The ratio changes. Thereby, the effective light source HV difference can be adjusted to a desired value, and the line width difference between the vertical pattern and the horizontal pattern formed or transferred onto the substrate can be adjusted as desired.

Up to this point, by rotating the shielding member 52 (in other words, the shaft 51) by the drive mechanism 53, the effective light source HV difference, and furthermore, the difference between the vertical pattern and the horizontal pattern formed or transferred onto the substrate have been explained. We have explained how to arbitrarily adjust the line width difference between the lines. In the following, by translating the shielding member 52 (in other words, the shaft 51) by the drive mechanism 53, the effective light source HV difference, and furthermore, the difference between the vertical pattern and the horizontal pattern formed or transferred onto the substrate will be explained. A method for arbitrarily adjusting the line width difference will be explained.

FIG. 5D shows an example of a region of the entire diffractive optical element 7 that is shielded by the adjustment unit 5. In the state illustrated in FIG. 5D, the axis 51 is located below the optical axis, and the shielding member 52 crosses the optical axis. In this case, a shadow region 75f of the shielding member 52 is formed spanning the second region 72 and the third region 73 of the diffractive optical element 7. The illuminated area of the original second area 72 and third area 73 has a smaller area due to the shadow area 75f, and the area 72f of the second area 72 is illuminated and the area 73f of the third area 73 is illuminated. be done. The distribution formed on the Fourier transform surface 9 by the regions 72f and 73f obtained by excluding the shadow region 75f from the illumination region 74 has a ring shape like the distribution 94f illustrated in FIG. 5D. In this example, since the area of the illuminated area 72f of the second area 72 and the area of the illuminated area 73f of the third area 73 are equal, the light amounts of the second area 72 and the third area 73 are equal. . Therefore, the distribution 94f has an annular shape with no HV difference, similar to the light intensity distribution of the annular shape 91 illustrated in FIG. 2(a).

FIG. 6 schematically shows the effect when the optical axis between the light source 1 and the diffractive optical element 7 deviates from the designed optical axis. In this example, the position of the adjustment unit 5 is the same as in FIG. 5A, but due to the optical axis shift of the routing optical system 2, the illumination area 74d, which is the area where the diffractive optical element 7 is illuminated, is changed from the designed illumination area 74 ( (see Figure 2). Here, it is assumed that the light intensity distribution in the illumination area 74 is uniform. When an illumination area 74d shifted from the designed illumination area 74 is illuminated, the distribution formed on the Fourier transform surface 9 is a distribution 94d, which is the same as or similar to the distribution 94a in FIG. 5B. The range of deviation from the illumination area 74 due to optical axis deviation is, for example, within ±2 mm, but within this range, the outer edge of the illumination area 74 is separated from the first area 71 of the diffractive optical element 7 and other areas (second area 72, third area The width of the first region 71 may be determined so as not to straddle the boundary with the region 73). Thereby, even if the illumination area 74 shifts due to optical axis shift, the distribution formed on the Fourier transform surface 9 can be prevented from being affected.

Exposure apparatus 100 and illumination optical system IL of the second embodiment will be described below. Matters not mentioned in the second embodiment may follow the first embodiment. In the second embodiment, the diffractive optical element 7 includes a first region 71, second regions 721, 722, and third regions 731, 732. The first region 71 is arranged to surround the second regions 721 and 722 and the third regions 731 and 732. The area composed of the second areas 721 and 722 and the third areas 731 and 732 is divided into two in the vertical direction and into two in the left and right direction, so that the area is divided into four in total. Second regions 721 and 722 are arranged at the upper left and lower right, and third regions 731 and 732 are arranged at the upper right and lower left. The second regions 721 and 722 can be understood as a first partial region and a second partial region, respectively, which are arranged diagonally to each other within the region surrounded by the first region 71. The third regions 731 and 732 can be understood as a third partial region and a fourth partial region that are arranged diagonally to each other within the region surrounded by the first region 71.

The total area of the second regions 721 and 722 and the total area of the third regions 731 and 732 are equal to each other. The light intensity distribution formed on the Fourier transform surface 9 by the first region 71 may have an annular shape 91 illustrated in FIG. 3(a). The light intensity distribution formed on the Fourier transform surface 9 by the second regions 721 and 722 may be a Y-direction dipole 92 illustrated in FIG. 3(b). The light intensity distribution formed on the Fourier transform surface 9 by the third regions 731 and 732 may be an X-direction dipole 93 illustrated in FIG. 3(c). Since the total area of the second regions 721, 722 and the total area of the third regions 731, 732 are equal to each other, when the illumination region 74 is illuminated, the light intensity distribution formed on the Fourier transform surface 9 has an annular shape. It has a ring shape similar to 91.

In the second embodiment, as illustrated in FIG. 7A, the adjustment unit 5 includes a shaft (supporting member) 51, shielding members 52a and 52b coupled to the shaft 51, and a shielding member by driving the shaft 51. A drive mechanism 53 that drives 52a and 52b may be included. The shielding member 52a and the shielding member 52b may be arranged on opposite sides of the axis 51. In one example, the axis 51 is parallel to the vertical boundary between the second regions 721, 722b and the third regions 731, 732 of the diffractive optical element 7, and both the axis 51 and the boundary intersect with the optical axis.

The drive mechanism 53 drives the shaft 51 (as a result, the shielding members 52a, 52b) by rotating the shaft 51 around a central axis extending in a direction intersecting the optical path of the light beam from the light source 1 to the diffractive optical element 7, for example. It may include a rotational drive. The driving of the shaft 51 (and consequently the shielding members 52a, 52b) by the driving mechanism 53 may include, for example, translational driving of the shaft 51 in a direction intersecting the optical path of the light beam from the light source 1 to the diffractive optical element 7. The shaft 51 may be replaced by a support member, such as a transparent plate, by which the shielding members 52a, 52b may be supported.

7B and 7C illustrate an example of a region of the entire diffractive optical element 7 that is shielded by the adjustment unit 5. As illustrated in FIG. 7B, when the shielding members 52a and 52b are perpendicular to the optical axis and directly facing the second regions 721 and 722 of the diffractive optical element 7, a shadow region 75a of the shielding member 52a is formed in the second region 721. As a result, a shadow area 75b of the shielding member 52b is formed in the second area 722. The second regions 721 and 722 include shadow regions 75a and 75b and the other non-shadow region 72a. The non-shadow area 72a has a smaller area than the original second areas 721 and 722. Since the shadow areas 75a and 75b are not formed in the third areas 731 and 732, the areas of the illuminated third areas 731 and 732 do not change. Therefore, the ratio of the amount of light that illuminates the second regions 721, 722 and the amount of light that illuminates the third regions 731, 732 changes, and the amount of light that illuminates the third region becomes relatively large. By illuminating the area excluding the shadow areas 75a and 75b from the illumination area 74, the light intensity distribution formed on the Fourier transform surface 9 becomes a double pole in the X direction, as shown in the distribution 94g illustrated in FIG. 7A. The strength of the corresponding portion is stronger than the strength of the portion corresponding to the Y-direction dipole, resulting in an annular shape. Distribution 94g indicates that the effective light source HV difference is +.

As illustrated in FIG. 7C, when the shielding member 52 is tilted from the direction perpendicular to the optical axis and directly faces the second regions 721, 722 of the diffractive optical element 7, the second regions 721, 722 of the diffractive optical element 7 Shadow areas 75a and 75b of the shielding members 52a and 52b are formed respectively. The second regions 721 and 722 include shadow regions 75a and 75b and the other non-shadow region 72a. The non-shadow area 72a has a smaller area than the original second areas 721 and 722. Since the shadow area 75a is not formed in the third areas 731 and 732, the area of the illuminated third area 73 does not change. By illuminating the area excluding the shadow areas 75a and 75b from the illumination area 74, the light intensity distribution formed on the Fourier transform surface 9 has a ring shape like the distribution 94h illustrated in FIG. 7B. The effective light source HV difference in the distribution 94h is larger than the distribution 94g and smaller than the annular shape 91.

By rotating the shielding member 52 (in other words, the shaft 51) by the drive mechanism 53, the area of the shadow formed on the diffractive optical element 7 changes, and the amount of light illuminating the second areas 721, 722 and the third area 731, 732 are changed. The ratio to the amount of illuminating light changes. Thereby, the effective light source HV difference can be adjusted to a desired value, and the line width difference between the vertical pattern and the horizontal pattern formed or transferred onto the substrate can be adjusted as desired.

FIG. 8A schematically shows the effect when the optical axis between the light source 1 and the diffractive optical element 7 deviates from the designed optical axis. In this example, the position of the adjustment unit 5 is the same as in FIG. 7B, but due to the optical axis shift of the routing optical system 2, the illumination area 74d, which is the area where the diffractive optical element 7 is illuminated, is shifted from the designed illumination area 74. Eccentric. In this example, unlike the first embodiment in which a uniform light amount distribution as shown in FIG. Assume that it has strength.

Since the illumination range 74d is eccentric, the center portion 74e is also eccentric. If the center portion 74e is not eccentric, the area of the overlap of the center portion 74e with the regions 721 and 722 is equal to the area of the overlap of the center portion 74e with the regions 731 and 732, as illustrated in FIG. 8B. . On the other hand, when the center portion 74e is eccentric to the upper left, as illustrated in FIG. 8C, the area of the overlapping portion of the center portion 74e with respect to the region 721 increases, while the area of the overlapping portion of the center portion 74e with respect to the region 722 increases. decrease. Therefore, the area of the overlapping portion of the center portion 74e with respect to the region 721 and the region 722 is almost unchanged from the state without eccentricity. Further, the area of the overlapping portion of the center portion 74e with respect to the region consisting of the region 731 and the region 732 is also almost unchanged from the state without eccentricity. At this time, the distribution formed on the Fourier transform surface 9 becomes a distribution 94i as illustrated in FIG. 8A. Distribution 94i is the same as or similar to distribution 94g.

As described above, according to the second embodiment, even if the illumination area 74 has a central portion 74e with high light intensity, even if the illumination area 74 is decentered due to optical axis deviation, the light formed on the Fourier transform surface 9 The intensity distribution is less affected by it.

The article manufacturing method according to the embodiment of the present invention is suitable for manufacturing articles such as micro devices such as semiconductor devices and elements having fine structures. The article manufacturing method of the present embodiment includes an exposure step (a step of exposing the substrate) in which a latent image pattern is formed on a photosensitive agent coated on a substrate using the above exposure device, and a latent image pattern is formed in the exposure step. and a developing step of developing the substrate. Additionally, the article manufacturing method includes other well-known processing steps (oxidation, deposition, deposition, doping, planarization, etching, resist stripping, dicing, bonding, packaging, etc.). The method for manufacturing an article according to the present embodiment is advantageous in at least one of the performance, quality, productivity, and production cost of the article compared to conventional methods.

The invention is not limited to the embodiments described above, and various changes and modifications can be made without departing from the spirit and scope of the invention. Therefore, the following claims are hereby appended to disclose the scope of the invention.

1 Light source 2 Routing optical system 3 Mirror 4 Parallel plane plate 5 Area changing mechanism 51 Axis 52 Light shielding member 53 Rotating mechanism 6 Exit angle preserving optical element 7 Diffractive optical element 8 Condenser lens 9 Fourier transform surface 10 Prism unit 11 Zoom lens unit 12 Multi-beam forming unit 13 Aperture 14 Condenser lens 15 Half mirror 16 Light amount measurement optical system 17 Sensor 18 Original plate 19 Projection optical system 20 Substrate

Claims (21)

An illumination optical system that forms a light intensity distribution on a pupil plane using a luminous flux from a light source and illuminates an object with the light from the pupil plane,
a first region, a second region, and a third region having different diffraction effects, the first region is arranged to surround the second region and the third region, and the light intensity distribution is applied to the pupil plane. a diffractive optical element to be formed;
Disposed between the light source and the diffractive optical element, the amount of light illuminating the second region and the amount of light illuminating the third region can be adjusted by blocking or attenuating a part of the luminous flux from the light source. an adjustment unit that adjusts the ratio of the
An illumination optical system characterized by: The adjustment unit is
a shielding member that blocks or attenuates a part of the luminous flux from the light source;
a drive mechanism that drives the shielding member;
The illumination optical system according to claim 1, characterized in that: The drive mechanism rotates the shielding member around an axis intersecting an optical path of the light beam from the light source to the diffractive optical element.
The illumination optical system according to claim 2, characterized in that: The drive mechanism translates the shielding member within a plane intersecting the optical path of the light beam from the light source to the diffractive optical element.
The illumination optical system according to claim 2, characterized in that: The drive mechanism translates the shielding member within a plane intersecting the optical path of the light beam from the light source to the diffractive optical element.
The illumination optical system according to claim 3, characterized in that: The adjustment unit further includes a support member that supports the shielding member, and the drive mechanism drives the shielding member by driving the support member.
The illumination optical system according to any one of claims 2 to 5, characterized in that: The support member includes a shaft that supports the shielding member.
The illumination optical system according to claim 6, characterized in that: the axis is parallel to a boundary line between the second region and the third region;
The illumination optical system according to claim 7, characterized in that: The second region includes a diffraction element forming at least two poles separated from each other in the first direction in the pupil plane,
The third region includes a diffraction element forming at least two poles separated from each other in a second direction perpendicular to the first direction in the pupil plane.
The illumination optical system according to any one of claims 1 to 8, characterized in that: The second region includes a first partial region and a second partial region arranged diagonally to each other within a region surrounded by the first region,
The third region includes a third partial region and a fourth partial region arranged diagonally to each other within the region surrounded by the first region.
The illumination optical system according to claim 9, characterized in that: An illumination optical system that forms a light intensity distribution on a pupil plane using a luminous flux from a light source and illuminates an object with the light from the pupil plane,
a first region, a second region, and a third region having different diffraction effects, the first region is arranged to surround the second region and the third region, and the light intensity distribution is applied to the pupil plane. a diffractive optical element to be formed;
an adjustment unit disposed between the light source and the diffractive optical element and adjusting the light intensity distribution formed on the pupil plane,
The adjustment unit includes a shielding member that blocks or attenuates a part of the luminous flux from the light source, and a drive mechanism that drives the shielding member.
An illumination optical system characterized by: The drive mechanism rotates the shielding member around an axis intersecting an optical path of the light beam from the light source to the diffractive optical element.
The illumination optical system according to claim 11, characterized in that: The drive mechanism translates the shielding member within a plane intersecting the optical path of the light beam from the light source to the diffractive optical element.
The illumination optical system according to claim 11, characterized in that: The drive mechanism translates the shielding member within a plane intersecting the optical path of the light beam from the light source to the diffractive optical element.
The illumination optical system according to claim 12, characterized in that: The adjustment unit further includes a support member that supports the shielding member, and the drive mechanism drives the shielding member by driving the support member.
The illumination optical system according to any one of claims 12 to 14. The support member includes a shaft that supports the shielding member.
16. The illumination optical system according to claim 15. the axis is parallel to a boundary line between the second region and the third region;
The illumination optical system according to claim 16, characterized in that: The second region includes a diffraction element forming at least two poles separated from each other in the first direction in the pupil plane,
The third region includes a diffraction element forming at least two poles separated from each other in a second direction perpendicular to the first direction in the pupil plane.
The illumination optical system according to any one of claims 11 to 17, characterized in that: The second region includes a first partial region and a second partial region arranged diagonally to each other within a region surrounded by the first region,
The third region includes a third partial region and a fourth partial region arranged diagonally to each other within the region surrounded by the first region.
The illumination optical system according to claim 18, characterized in that: An exposure apparatus comprising an illumination optical system that illuminates an original, and a projection optical system that projects a pattern of the original onto a substrate,
The illumination optical system includes the illumination optical system according to any one of claims 1 to 19.
An exposure device characterized by: An article manufacturing method for manufacturing an article, the method comprising:
an exposure step of exposing a substrate using the exposure apparatus according to claim 20;
a developing step of developing the substrate that has undergone the exposure step;
obtaining the article from the substrate that has undergone the development step;
A method for manufacturing an article, comprising: