Optical device and method for adjusting the optical device

Abstract

The present invention provides an optical device that allows for easy adjustment of light intensity and a method for adjusting the optical device. [Solution] The optical device 1 according to the present disclosure is a filter 10 arranged in the optical path L0 of light L1 including EUV light, and comprises a filter 10 having one surface 11 and another surface 12 facing the one surface 11, and a support part 20 that can change the orientation of the filter 10 so as to change the angle between the perpendicular 13 of the one surface 11 of the filter 10 and the principal optical axis C of the light L1, and supports the filter 10 in multiple orientations, wherein the transmittance of light L1 transmitted through the filter 10 changes as the angle changes.

Description

Technical Field

[0001] The present disclosure relates to an optical device and a method for adjusting an optical device.

Background Art

[0002] In an inspection apparatus that inspects an object such as a photomask using light having a wavelength of EUV (Extreme Ultra Violet), or an exposure apparatus that forms a pattern on a wafer using light having a wavelength of EUV, it is preferable that the amount of EUV light illuminating an object such as an inspection target, a patterning device, and a wafer can be arbitrarily adjusted.

[0003] For example, Patent Document 1 discloses an optical device including a plurality of mirror elements whose postures can be individually changed, and having a mirror array capable of adjusting the amount of EUV light by irradiating a part of the light beam of EUV light onto an object such as a photomask and introducing a part into a light trap.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] An optical device that individually changes the posture of mirror elements, such as the mirror array of Patent Document 1, is expected to have complexity in structure and control, and complexity in maintenance. An optical device capable of adjusting the amount of light in a simpler method is desired.

[0006] An object of the present disclosure is to solve such problems and provide an optical device and a method for adjusting an optical device that can easily adjust the amount of light.

Means for Solving the Problems

[0007] The optical apparatus according to this disclosure is a filter arranged in the optical path of light including EUV light, and comprises a filter having one surface and another surface opposite to the one surface, and a support portion capable of supporting the filter in a plurality of orientations, wherein the orientation of the filter is changed so as the angle between the perpendicular to the one surface of the filter and the principal optical axis of the light changes, and the transmittance of the light passing through the filter changes as the angle changes.

[0008] In the optical device described above, the plurality of orientations may include a first orientation in which the light in the optical path is incident on one surface of the filter and the angle is a first angle, a second orientation in which the light in the optical path is incident on one surface of the filter and the angle is a second angle greater than the first angle, and a third orientation in which the light in the optical path is not incident on one surface of the filter.

[0009] The optical apparatus according to this disclosure comprises a filter arranged in the optical path of light, the filter having one surface and the other surface opposite to the one surface, and a support that can support the filter in a plurality of positions, such that the orientation of the filter changes so that the angle between the perpendicular to the one surface of the filter and the principal optical axis of the light changes, wherein the transmittance of the light passing through the filter changes as the angle changes, and the plurality of positions include a first position in which the light in the optical path is incident on the one surface of the filter and the angle is a first angle, a second position in which the light in the optical path is incident on the one surface of the filter and the angle is a second angle greater than the first angle, and a third position in which the light in the optical path is not incident on the one surface of the filter.

[0010] The optical apparatus according to this disclosure comprises a filter arranged in the optical path of light, the filter having one surface and the other surface opposite to the one surface, and a support portion capable of supporting the filter in a plurality of positions, wherein the filter's orientation is changed such that the angle between the perpendicular to the one surface of the filter and the principal optical axis of the light changes, and the transmittance of the light passing through the filter changes as the angle changes, the plurality of positions include a first position in which the light in the optical path is incident on the one surface of the filter and the angle is a first angle, and a second position in which the light in the optical path is incident on the one surface of the filter and the angle is a second angle greater than the first angle, and the support portion supports the filter in the second position at a first time and supports the filter in the first position at a second time later than the first time.

[0011] In the optical device described above, the support portion may be capable of supporting the filter in the second position while changing the position of the filter between the first position and the third position so that the angle changes.

[0012] In the optical device described above, the support portion may change the orientation of the filter using the edge of the filter as a pivot point, or using a point outside the edge of the filter as viewed from the principal optical axis as a pivot point, so that in the third orientation, the filter is positioned outside the light beam of the light in the optical path.

[0013] In the optical device described above, the light in the optical path includes convergent light that is focused toward a predetermined focusing position, or divergent light that diverges from the predetermined focusing position, and the filter may be tilted toward the focusing position in the second orientation compared to the first orientation.

[0014] In the optical device described above, the light in the optical path includes convergent light that is focused toward a predetermined focusing position, or divergent light that diverges from the predetermined focusing position, and the filter may be tilted in the second position toward the opposite side of the focusing position compared to the first position.

[0015] In the optical device described above, the multiple orientations are formed by the rotation of the filter with a virtual axis as the axis of rotation, and the virtual axis may penetrate a part of the filter, a part of the holding part that holds the filter, and a part of the light beam.

[0016] In the optical device described above, the multiple positions may be formed by sliding a part of the filter or a part of the holding portion that holds the filter along a rail.

[0017] The optical device described above has a TP mode for inspecting a mask with a pellicle and an NP mode for inspecting a mask without a pellicle, and the support portion may support the filter in the first or second position, at least in the TP mode.

[0018] In the optical device described above, the filter includes a first filter and a second filter, the first filter, a collector mirror, and the second filter are arranged in order along the direction in which the light travels from a light source emitting the light, and the support portion may support the second filter in multiple positions.

[0019] The optical device described above may further include a shutter that blocks the light between the collector mirror and the second filter.

[0020] A method for adjusting an optical device according to the present disclosure includes a filter placed in the optical path of light including EUV light, the filter having one surface and another surface opposite to the one surface, and a support portion capable of supporting the filter in a plurality of said surfaces, by changing the orientation of the filter such that the angle between the one surface of the filter and the principal optical axis of the light changes, the method comprising the steps of: placing the filter in the optical path such that the transmittance of the light passing through the filter changes as the angle changes; and changing the orientation of the filter to one of the plurality of said orientations.

[0021] In the above method for adjusting the optical device, in the step of changing the orientation of the filter to one of a plurality of orientations, the plurality of orientations may include: a first orientation in which the light in the optical path is incident on one of the surfaces of the filter and the angle is a first angle; a second orientation in which the light in the optical path is incident on one of the surfaces of the filter and the angle is a second angle greater than the first angle; and a third orientation in which the light in the optical path is not incident on one of the surfaces of the filter.

[0022] A method for adjusting an optical device according to the present disclosure includes a filter arranged in the optical path of light, the filter having one surface and the other surface opposite to the one surface, and a support capable of supporting the filter in a plurality of said orientations, by changing the orientation of the filter such that the angle between the perpendicular to the one surface of the filter and the principal optical axis of the light changes, the method comprising: placing the filter in the optical path such that the transmittance of the light passing through the filter changes as the angle changes; and changing the orientation of the filter to one of the plurality of said orientations, wherein the plurality of said orientations include: a first orientation in which the light in the optical path is incident on the one surface of the filter and the angle is a first angle; a second orientation in which the light in the optical path is incident on the one surface of the filter and the angle is a second angle greater than the first angle; and a third orientation in which the light in the optical path is not incident on the one surface of the filter.

[0023] The method for adjusting an optical device according to the present disclosure is a method for adjusting an optical device including a filter disposed in an optical path of light, the filter having one surface and another surface facing the one surface, a support portion that changes the posture of the filter so that an angle formed by a perpendicular line to the one surface of the filter and the principal optical axis of the light changes, and that can support the filter in a plurality of the postures. The method includes: disposing the filter in the optical path such that the transmittance of the light transmitted through the filter changes as the angle changes; and changing the posture of the filter to any one of the plurality of the postures. In the step of changing the posture of the filter to any one of the plurality of the postures, the plurality of the postures include a first posture in which the light in the optical path is incident on the one surface of the filter and the angle is a first angle, and a second posture in which the light in the optical path is incident on the one surface of the filter and the angle is a second angle greater than the first angle. The support portion supports the filter in the second posture at a first time and supports the filter in the first posture at a second time after the first time.

[0024] In the method for adjusting the optical device, in the step of changing the posture of the filter to any one of the plurality of the postures, the support portion may support the filter in the second posture while changing the posture of the filter between the first posture and a third posture so that the angle changes.

[0025] In the method for adjusting the optical device, the support portion changes the posture of the filter with an edge portion of the filter as a fulcrum or a point outside the edge portion as viewed from the principal optical axis. In the step of changing the posture of the filter to any one of the plurality of the postures, the support portion may dispose the filter outside a light beam of the light in the optical path in the case of the third posture.

[0026] In the adjustment method of the optical device, the light in the optical path includes converging light that converges toward a predetermined condensing position or diverging light that diverges from a predetermined condensing position. In the step of changing the posture of the filter to any one of the plurality of postures, the filter may be inclined toward the condensing position side more than the first posture in the second posture.

[0027] In the adjustment method of the optical device, the light in the optical path includes converging light that converges toward a predetermined condensing position or diverging light that diverges from a predetermined condensing position. In the step of changing the posture of the filter to any one of the plurality of postures, the filter may be inclined toward the opposite side of the condensing position more than the first posture in the second posture.

[0028] In the step of changing the posture of the filter to any one of the plurality of postures in the adjustment method of the optical device, the plurality of postures are formed by rotation of the filter with a virtual axis as a rotation axis, and the virtual axis may penetrate a part of the filter or a part of a holding portion that holds the filter, and a part of the light beam of the light.

[0029] In the step of changing the posture of the filter to any one of the plurality of postures in the adjustment method of the optical device, the plurality of postures may be formed by sliding a part of the filter or a part of a holding portion that holds the filter along a rail.

[0030] In the adjustment method of the optical device, the optical device has a TP mode for inspecting a mask with a pellicle and an NP mode for inspecting a mask without a pellicle. In the step of changing the posture of the filter to any one of the plurality of postures, the support portion may support the posture of the filter in the first posture or the second posture at least in the case of the TP mode.

[0031] In the above method for adjusting the optical device, the filter includes a first filter and a second filter, the first filter, the collector mirror and the second filter are arranged in order from the light source that emits the light in the direction in which the light travels, and in the step of changing the orientation of the filter to one of a plurality of orientations, the support portion may support the second filter in the plurality of orientations.

[0032] In the above method for adjusting the optical device, the optical device may further include a shutter that blocks the light between the collector mirror and the second filter. [Effects of the Invention]

[0033] According to this disclosure, it is possible to provide an optical device that can easily adjust the amount of light, and a method for adjusting the optical device. [Brief explanation of the drawing]

[0034] [Figure 1] This is a diagram illustrating an optical device according to Embodiment 1. [Figure 2] This is an enlarged view illustrating a filter in the optical device according to Embodiment 1. [Figure 3] This figure illustrates the relationship between the orientation of the filter and the transmittance and light intensity in the optical device according to Embodiment 1. [Figure 4] This is a cross-sectional view illustrating an object to be illuminated by light in the optical device according to Embodiment 1. [Figure 5] This is a diagram illustrating an optical device according to a modified example 1 of Embodiment 1. [Figure 6] This is a diagram illustrating an optical device according to a modified example 1 of Embodiment 1. [Figure 7] This is a diagram illustrating an optical device according to a modified example 2 of Embodiment 1. [Figure 8] This figure illustrates the effects of the optical apparatus according to Embodiment 1, the optical apparatus according to Modification 1, and the optical apparatus according to Modification 2. [Figure 9]This figure illustrates the effects of the optical apparatus according to Embodiment 1, the optical apparatus according to Modification 1, and the optical apparatus according to Modification 2. [Figure 10] This is a diagram illustrating an optical device according to a modified example 3 of Embodiment 1. [Figure 11] This is a side view illustrating an optical device according to a modified example 4 of Embodiment 1. [Figure 12] This is a top view illustrating an optical device according to a modified example 4 of Embodiment 1. [Figure 13] This is a top view illustrating an optical device according to a modified example 4 of Embodiment 1. [Figure 14] This is a top view illustrating an optical device according to a modified example 4 of Embodiment 1. [Figure 15] This is a top view illustrating an optical device according to a modified example 4 of Embodiment 1. [Figure 16] This is a diagram illustrating an optical device according to a modified example 5 of Embodiment 1. [Figure 17] This is a flowchart illustrating an example of an adjustment method for an optical device according to Embodiment 1. [Figure 18] This is a diagram illustrating an optical device according to Embodiment 2. [Modes for carrying out the invention]

[0035] The specific configuration of this embodiment will be described below with reference to the drawings. The following description illustrates preferred embodiments of the present disclosure, and the scope of the present disclosure is not limited to the following embodiments. In the following description, the same reference numerals indicate substantially the same thing. Some reference numerals and hatching have been omitted to avoid cluttering the drawings.

[0036] <Embodiment 1> The optical apparatus according to Embodiment 1 will now be described. The optical apparatus of this embodiment may include an inspection device for inspecting an object, a review device for displaying the imaging results of the object on a display or the like, and an exposure device for patterning the object. One objective of the optical apparatus of this embodiment is to continuously change the amount of light, such as illumination light including EUV light. Several methods can be used to adjust the amount of EUV light, such as by inserting or removing a filter, by controlling the emission state of the light source, and by controlling the pressure of a light-absorbing gas in the optical path.

[0037] Specifically, adjusting the light intensity by inserting and removing filters is done by switching between an inserted state, where the filter with its incident surface perpendicular to the principal optical axis of the EUV light is inserted into the EUV light, and a retracted state, where the inserted filter is moved away from the EUV light. Therefore, for example, if the transmittance is to be changed by the thickness of the filter, multiple filters of different thicknesses and insertion / removal mechanisms are required. Thus, it is necessary to prepare multiple optical components, which increases costs. Also, it is not possible to continuously change the light intensity. Furthermore, due to circumstances such as light being absorbed by the air in the chamber, the gas pressure in the chamber may be lowered, for example, to a vacuum. Inserting and removing filters installed in such a vacuum atmosphere while maintaining the vacuum atmosphere requires a complex mechanism, and the mechanism becomes more complex if there are multiple filters to be inserted or removed.

[0038] Adjusting the light source by controlling its emission state specifically involves adjusting the light source's output. However, this method prevents the light source from emitting light at a constant output, thus compromising the stability of the light source's emission state. Furthermore, it becomes difficult to continuously change the light intensity.

[0039] The adjustment of the light-absorbing gas in the optical path by controlling its pressure specifically involves adjusting the pressure of the gas within the chamber in which the optical path is located. However, changing the gas pressure within the chamber may cause deterioration or displacement of the optical components placed within the chamber. This embodiment solves these problems.

[0040] Figure 1 is a configuration diagram illustrating an optical device 1 according to Embodiment 1. Figure 2 is an enlarged view illustrating a filter 10 in the optical device 1 according to Embodiment 1. As shown in Figures 1 and 2, the optical device 1 comprises a filter 10 and a support portion 20. The filter 10 is positioned in the optical path L0 of light L1. The optical path L0 includes the path of light L1 in a predetermined region. The predetermined region may include, for example, the inside of a chamber or the space between predetermined optical members. As will be described later in Embodiment 2, it is preferable that the filter 10 be positioned at a pupil position other than the image plane, such as the focusing position IF.

[0041] Light L1 may include EUV light. However, light L1 is not limited to light L1 that includes EUV light. Light L1 may include light with wavelengths shorter than or equal to EUV wavelength. Light L1 may be light with wavelengths shorter than or longer than EUV wavelength. It may be light that includes multiple wavelength ranges. Light L1 is, for example, illumination light. Illumination light may be used, for example, for inspection illumination of an object in an inspection device or for illumination of an object in a review device. However, light L1 is not limited to illumination light and may also be exposure light. Exposure light may be used, for example, for patterning an object in an exposure device.

[0042] Here, for the sake of explaining optical device 1, we introduce an XYZ Cartesian coordinate system. Within the optical path L0, the direction in which the principal optical axis C of light L1 extends is defined as the Z-axis direction. The direction in which light L1 travels is defined as the +Z-axis direction. The two directions perpendicular to the principal optical axis C of light L1 are defined as the X-axis direction and the Y-axis direction.

[0043] The filter 10 may be plate-shaped, having one surface 11 and the other surface 12. One surface 11 faces the other surface 12. For example, one surface 11 and the other surface 12 may be planar. One surface 11 may be parallel to the other surface 12. The transmittance of light L1 passing through the filter 10 changes as the angle θ between the perpendicular 13 of one surface 11 and the principal optical axis C of light L1 changes.

[0044] The filter 10 may include, for example, films of zirconium (Zr), silicon (Si), and carbon nanotubes. The filter 10 may also consist of multiple films of the same or different types laminated together. The filter 10 may also include a mesh-structured sheet. The mesh structure may be constructed by weaving fine wires of aluminum (Al), stainless steel, etc., or by providing numerous pores in a base metal. The filter 10 may also consist of films of zirconium (Zr), silicon (Si), and carbon nanotubes laminated on a mesh-structured sheet. The filter 10 may consist of one film, or multiple films of the same or different types laminated on a mesh-structured sheet.

[0045] The filter 10 has an edge portion 14. The edge portion 14 connects the edge of one surface 11 and the edge of the other surface 12. The edge portion 14 may be connected to a retaining portion 15 that holds the filter 10. One end of the retaining portion 15 may be connected to the edge portion 14. The other end of the retaining portion 15 may be connected to a predetermined point 16. Point 16 is a point 16 that is outside the edge portion 14 when viewed from the principal optical axis C of light L1.

[0046] The support part 20 changes the orientation of the filter 10. Specifically, the support part 20 changes the orientation of the filter 10 such that the transmittance of the light L1 passing through the filter 10 changes as the angle θ between the perpendicular 13 of one surface 11 of the filter 10 and the principal optical axis C of the light L1 changes. The support part 20 may also change the orientation of the filter 10 by tilting the filter 10 and the holding part 15 with point 16 as the pivot point. In this way, the support part 20 may also change the orientation of the filter 10 with point 16 outside the edge part 14 as viewed from the principal optical axis C of the light L1 as the pivot point.

[0047] The support portion 20 may include, for example, a drive member such as a motor. However, the support portion 20 is not limited to a drive member such as a motor, as long as it can change the orientation of the filter 10. For example, the support portion 20 may include a member that moves or rotates by magnetic force. Specifically, the support portion 20 may include a magnet. The user may move or rotate the support portion 20 by bringing another magnet close to the magnet of the support portion 20. In this way, the user may change the orientation of the filter 10 by moving or rotating the support portion 20 with a magnet.

[0048] The support unit 20 changes the orientation of the filter 10 so that the angle between the perpendicular line of one surface 11 of the filter 10 and the principal optical axis C of the light L1 changes. The support unit 20 can support the filter 10 in multiple orientations. These multiple orientations include a first orientation 31, a second orientation, and a third orientation. A zero orientation 30 may also be included in the multiple orientations. The orientation of the filter 10 changed by the support unit 20 may be variable to, for example, a zero orientation 30, a first orientation 31, a second orientation 32, and a third orientation 33. The support unit 20 may also change the orientation of the filter 10 to any other orientation.

[0049] The 0th orientation 30 is the orientation in which light L1 in the optical path L0 is incident on one surface 11 of the filter 10, with an angle θ of 0°. In other words, in the 0th orientation 30, the perpendicular 13 of one surface 11 and the principal optical axis C of light L1 are parallel. In the 0th orientation 30, all of the light beam L2 of light L1 in the optical path L0 that reaches downstream of the filter 10 is incident on one surface 11 of the filter 10. The 1st orientation 31 is the orientation in which light L1 in the optical path L0 is incident on one surface 11 of the filter 10, with an angle θ of the 1st angle θ1. In the 1st orientation 31, all of the light beam L2 of light L1 in the optical path L0 that reaches downstream of the optical path L0 is incident on one surface 11 of the filter 10. The second orientation 32 is an orientation in which light L1 in the optical path L0 is incident on one surface 11 of the filter 10, and the angle θ is the second angle θ2. The second angle θ2 is greater than the first angle θ1. In the second orientation 32, all of the light beam L2 of light L1 in the optical path L0 that reaches downstream of the filter 10 is incident on one surface 11 of the filter 10. The third orientation 33 is an orientation in which light L1 in the optical path L0 is not incident on one surface 11 of the filter 10. The angle θ in the third orientation 33 is the third angle θ3. The third angle θ3 is greater than the first angle θ1 and the second angle θ2. In the third orientation 33, all of the light beam L2 of light L1 in the optical path L0 that reaches downstream of the filter 10 is not incident on one surface 11 of the filter 10. Angles θ1, θ2, and θ3 are mutually distinct angles. The angles θ1, θ2, and θ3 may include a predetermined range. Angle θ3 > angle θ2 > angle θ1 may be the case. Therefore, the support part 20 may be able to support the filter 10 in the second position 32 while changing the filter 10's posture between the first position 31 and the third position 33, while changing the angle θ. This simplifies the mechanism.

[0050] The 0th posture 30 may be an example of the 1st posture 31. In this case, the 0th posture 30 is an example where the angle θ1 is 0° in the 1st posture 31. Therefore, the 1st posture 31 may include the 0th posture 30, and in some cases, the 0th posture 30 and the 1st posture 31 are not distinguished and are simply described and explained as the 1st posture 31.

[0051] Figure 3 illustrates the relationship between the orientation of the filter 10 and the transmittance and light intensity in the optical device 1 according to Embodiment 1. As shown in Figure 3, for example, the angle θ in the 0th orientation 30 is 0°, the angle θ in the 1st orientation 31 is 10°, and the angle θ in the 2nd orientation 32 is 20°. The angle θ in the 3rd orientation 33 is the angle at which light L1 does not pass through the filter 10. In this example, the transmittances of the 0th orientation 30, the 1st orientation 31, the 2nd orientation 32, and the 3rd orientation 33 are 80%, 60%, 40%, and 100%, respectively. Note that since light L1 does not pass through the filter 10 in the 3rd orientation 33, it is not strictly a transmittance. If we set the light intensity of light L1 on the -Z axis side of filter 10 to 100, then the light intensity of light L1 on the +Z axis side of filter 10 in the 0th posture 30, 1st posture 31, 2nd posture 32, and 3rd posture 33 are 80, 60, 40, and 100, respectively. Except for the 3rd posture 33, the luminous flux L2 of light L1 is contained within one surface 11 of filter 10.

[0052] Note that the transmittance and light intensity shown in Figure 3 are examples only, and depending on the material, structure, and thickness of the filter 10, other desired transmittance and light intensity values ​​may be set.

[0053] The third orientation 33 is any orientation in which the light L1 in the optical path L0 does not enter one of the surfaces 11 of the filter 10. The third orientation 33 may also be an orientation in which one of the surfaces 11 of the filter 10 is displaced in a direction perpendicular to the optical axis of the light L1 in the optical path L0, compared to the other orientations (first orientation 31, second orientation 32).

[0054] One example of the application of filter 10 is the adjustment of the light intensity of illumination light L1 for inspection of photomasks with and without pellicles. Photomasks with pellicles are sometimes called pellicle masks, and photomasks without pellicles are sometimes called non-pellicle masks.

[0055] Figure 4 is a cross-sectional view illustrating an object 50 illuminated by light L1 in the optical device 1 according to Embodiment 1. As shown in Figure 4, the object 50 may include a photomask 51. However, the object 50 is not limited to a photomask 51 and may also be a semiconductor substrate, a semiconductor chip, etc. The object 50 may have a pattern 53 on the upper surface 52 of the photomask 51. The object 50 may also have a pellicle 54 covering the pattern 53. When the object 50 is illuminated with light L1 including EUV light, the pellicle 54 may be damaged depending on the amount of light L1.

[0056] Therefore, the optical device 1 of this embodiment adjusts the amount of light L1 by changing the orientation of the filter 10. For example, the optical device 1 may have a TP mode for inspecting a mask with a pellicle 54 and an NP mode for inspecting a mask without a pellicle 54. In the TP mode, the support unit 20 changes the orientation of the filter 10 to a first orientation 31 and a second orientation 32 so that light L1 passes through the filter 10. The support unit 20 may support the filter 10 in the first orientation 31 or the second orientation 32, at least in the TP mode. This makes it possible to suppress damage to the pellicle 54.

[0057] In contrast, in NP mode, the support unit 20 may support the filter 10 in a third position 33 in addition to the first position 31 and the second position 32. This allows for a greater light intensity, thereby improving inspection accuracy.

[0058] <Example 1> Figures 5 and 6 are configuration diagrams illustrating an optical device 1a according to a modified example 1 of Embodiment 1. As shown in Figure 5, the light L1 traveling in the +Z direction may include focused light that converges toward the focusing position IF. Also, as shown in Figure 6, the light L1 traveling in the +Z direction may include divergent light that diverges from the focusing position IF.

[0059] As shown in Figures 5 and 6, the support portion 20 may change the orientation of the filter 10 using the edge portion 14 of the filter 10 as a pivot point. In the third orientation 33, the support portion 20 positions the filter 10 outside the light beam L2 of the light L1 in the optical path L0. With this configuration, the holding portion 15 can be omitted compared to the optical device 1 of Embodiment 1. Therefore, costs can be reduced. However, the optical device 1a of this modified example requires an angle θ3 that is larger than the angle θ3 in the optical device 1 of Embodiment 1 in order to change to the third orientation 33. In contrast, although the optical device 1 of Embodiment 1 requires the holding portion 15, the angle θ3 required to change to the third orientation 33 can be smaller than that of the optical device 1a of Modified Example 1.

[0060] <Modification 2> Figure 7 is a configuration diagram illustrating an optical device 1b according to a modified example 2 of Embodiment 1. As shown in Figure 7, the light L1 traveling in the +Z axis direction within the optical path L0 may include converged light that is focused toward a predetermined focusing position IF. In this case, when changing to the second posture 32, the support 20 may tilt the filter 10 toward the opposite side of the focusing position IF compared to the first posture 31. That is, the support 20 may tilt the filter 10 toward the -Z axis direction.

[0061] Furthermore, the light L1 traveling in the +Z axis direction within the optical path L0 may include divergent light emitted from a predetermined focusing position IF. In this case as well, when changing to the second posture 32, the support unit 20 may tilt the filter 10 to the opposite side of the focusing position IF compared to the first posture 31. In other words, the support unit 20 may tilt the filter 10 towards the +Z axis direction.

[0062] Thus, in both cases where the convergent light travels along the +Z axis and where the divergent light travels along the +Z axis, the support 20 may tilt the filter 10 to the opposite side of the focusing position IF compared to the first posture 31 when changing to the second posture 32. As a result, in the second posture 32, the filter 10 is tilted to the opposite side of the focusing position IF compared to the first posture 31.

[0063] On the other hand, as shown in Figure 1 above, the light L1 traveling in the +Z axis direction within the optical path L0 may include convergent light that focuses toward a predetermined focusing position IF. Furthermore, the light L1 traveling in the +Z axis direction within the optical path L0 may also include divergent light that diverges from the predetermined focusing position IF. In either case, when changing to the second posture 32, the support unit 20 may tilt the filter 10 toward the focusing position IF compared to the first posture 31. As a result, in the second posture 32, the filter 10 is tilted toward the focusing position IF compared to the first posture 31.

[0064] Figures 8 and 9 illustrate the effects of the optical device 1 according to Embodiment 1, the optical device 1a according to Modification 1, and the optical device 1b according to Modification 2. As shown in Figures 8 and 9, when changing to the second posture 32, the support 20 may tilt the filter 10 to the opposite side of the focusing position IF compared to the first posture 31. With this configuration, the filter 10 can be tilted to the side where the light L1 is not focused, thereby suppressing the degradation of the filter 10. However, in this case, the range of angles θ in which the entire light beam L2 of the light L1 in the optical path L0 is incident on one surface 11 of the filter 10 becomes narrower. In order to have the same angle range as when tilted towards the focusing position IF, it is necessary to increase the area of ​​one surface 11.

[0065] On the other hand, when changing to the second posture 32, the support part 20 may tilt the filter 10 toward the focusing position IF side compared to the first posture 31. With this configuration, the area of ​​one surface 11 can be reduced in order to have the same angular range as when tilted toward the opposite side of the focusing position IF. In addition, the movement of the filter 10 when changing to the third posture 33 can be reduced. However, since the filter 10 is tilted toward the side where the light L1 is focused, the filter 10 is more prone to deterioration.

[0066] <Variation 3> Figure 10 is a configuration diagram illustrating an optical device 1c according to a modification 3 of Embodiment 1. As shown in Figure 10, the support portion 20 may rotate the filter 10 using a virtual axis that passes through a part of the filter 10 and a part of the light beam L2 as the axis of rotation. For example, the virtual axis may extend in the direction of the X axis. The virtual axis also passes through the central part of the side surface on the +X axis side and the central part of the side surface on the -X axis side of the filter 10. In this modification, the multiple orientations of the filter 10 are formed by the rotation of the filter 10 with the virtual axis as the axis of rotation. The virtual axis passes through a part of the filter 10 and a part of the light beam L2. In the third orientation 33, when the light beam L2 does not enter one of the surfaces 11, the support portion 20 positions the filter 10 inside the light beam L2. By adopting this configuration, the holding portion 15 is unnecessary, and the range of motion of the filter 10 can be reduced, so the filter 10 and the support portion 20 can be made more compact. Furthermore, when the filter 10 is in the third position 33, the light L1 is blocked by the edge portion 14 of the filter 10.

[0067] <Modification 4> Figure 11 is a side view illustrating an optical device 1d according to modification 4 of Embodiment 1. Figures 12 to 15 are top views illustrating an optical device 1d according to modification 4 of Embodiment 1. Figure 12 shows the 0th posture 30, Figure 13 shows the 1st posture 31, Figure 14 shows the 2nd posture 32, and Figure 15 shows the 3rd posture 33. As shown in Figures 11 and 12 to 15, the support portion 20 rotates the filter 10 using a virtual axis that passes through a part of the holding portion 15 that holds the filter 10 and a part of the light beam L2 as the axis of rotation. For example, the virtual axis may extend in the X-axis direction. The support portion 20 is positioned on the virtual axis, sandwiching the light beam L2. The holding portion 15 connects the side of the filter 10 on the +X-axis side to the support portion 20 on the +X-axis side. The holding portion 15 also connects the side of the filter 10 on the -X-axis side to the support portion 20 on the -X-axis side. In this modified example, the multiple orientations of the filter 10 are formed by the rotation of the filter 10 around a virtual axis. The virtual axis passes through a part of the holding part 15 that holds the filter 10, and a part of the light beam L2. With this configuration, even if there is a pivot point on either side of the light beam L2, the support part 20 can rotate the filter 10 around the virtual axis.

[0068] <Modification 5> Figure 16 is a configuration diagram illustrating an optical device 1e according to a modification 5 of Embodiment 1. As shown in Figure 16, the support portion 20 may slide a part of the filter 10 or a part of the holding portion 15 that holds the filter 10 along the rail 40. In this modification, multiple positions of the filter 10 are formed by sliding a part of the filter 10 or a part of the holding portion 15 that holds the filter 10 along the rail 40. In this way, the optical device 1e does not require a pivot point when changing the position of the filter 10, and this can also be achieved by a link mechanism. Therefore, the degree of freedom in the configuration of the optical device 1e can be improved.

[0069] <Method for adjusting optical devices> Next, a method for adjusting the optical device 1 will be described. Figure 17 is a flowchart illustrating an example of the adjustment method for the optical device 1 according to Embodiment 1. As shown in Figure 17, the adjustment method for the optical device 1 includes step S11 of placing the filter 10 in the optical path L0 of the light L1 and step S12 of changing the orientation of the filter 10. Here, the light L1 may include EUV light.

[0070] In step S11, a filter 10 having one surface 11 and the other surface 12 is placed in the optical path L0 of the light L1. Specifically, a filter 10 is placed in the optical path L0 such that the transmittance of the light L1 passing through the filter 10 changes as the angle between the perpendicular 13 of one surface 11 of the filter 10 and the principal optical axis C of the light L1 changes.

[0071] In step S12, the orientation of the filter 10 is changed to one of several orientations such that the angle between the perpendicular 13 of one surface 11 of the filter 10 and the principal optical axis C of the light L1 changes, thereby changing the transmittance of the light L1 that passes through the filter 10.

[0072] In step S12, the multiple postures may include a first posture 31, a second posture 32, and a third posture 33. The posture of the filter 10, which is changed by the support 20, may be variable between the first posture 31, the second posture 32, and the third posture 33. The first posture 31 may include a zero posture 30. The support 20 may be able to support the filter 10 in the second posture 32 while changing the posture of the filter 10 between the first posture 31 and the third posture 33 by changing the angle θ. In addition, in the case of the third posture 33, the support 20 may position the filter 10 outside the light beam L2 of the light L1 in the optical path L0. In the case of the second posture 32, the support 20 may tilt the filter 10 towards the focusing position IF side compared to the first posture 31. As a result, in the second posture, the filter 10 is tilted towards the focusing position IF side compared to the first posture 31. Furthermore, in the case of the second posture 32, the support part 20 may tilt the filter 10 to the opposite side of the focusing position IF compared to the first posture 31. As a result, in the second posture, the filter 10 is tilted to the opposite side of the focusing position IF compared to the first posture 31.

[0073] In step S12, the multiple orientations of the filter 10 may be formed by rotating the filter 10 around a virtual axis as the axis of rotation. The virtual axis may pass through a part of the filter 10 or a part of the holding part 15 that holds the filter 10, and a part of the light beam L2. Specifically, the support part 20 may rotate the filter 10 around a virtual axis that passes through a part of the filter 10 or a part of the holding part 15 that holds the filter 10, and a part of the light beam L2 as the axis of rotation. Alternatively, the multiple orientations of the filter 10 may be formed by sliding a part of the filter 10 or a part of the holding part 15 that holds the filter 10 along the rail 40. Specifically, the support part 20 may slide a part of the filter 10 or a part of the holding part 15 that holds the filter 10 along the rail 40.

[0074] <Embodiment 2> Next, an optical device of Embodiment 2 will be described. This embodiment describes an inspection device for inspecting an object 50 illuminated by light L1, as an example of an optical device. The optical device may be an exposure device that exposes the object 50 with light L1, or a review device that displays the object 50 illuminated by light L1 on a display or the like. Figure 18 is a configuration diagram illustrating an inspection device 2 according to Embodiment 2. As shown in Figure 18, the inspection device 2 includes an illumination optical system 60 and an imaging optical system 70.

[0075] The illumination optical system 60 illuminates the object 50 using light L1 as illumination light. The illumination optical system 60 includes, for example, a light source 61, a filter 10a, a collector mirror 62, a filter 10b, a support part 20, an ellipsoidal mirror 63, and a recessed mirror 64. The illumination optical system 60 may further include a shutter 41. In this embodiment, the filter 10 includes filter 10a and filter 10b.

[0076] The imaging optical system 70 captures an image of the object 50 illuminated by light L1. The imaging optical system 70 includes a perforated concave mirror 71, a convex mirror 72, and a detector 73. The perforated concave mirror 71 and the convex mirror 72 constitute a Schwarzschild magnifying optical system. The illumination optical system 60 and the imaging optical system 70 may further include optical components other than those described above, or any of the above optical components may be omitted.

[0077] For the sake of explanation, the XYZ Cartesian coordinate system is aligned with the principal optical axis C of light L1 in the optical path L0 between the collector mirror 62 and the ellipsoidal mirror 63.

[0078] The light source 61 generates light L1, which includes EUV light, as illumination light. The light source 61 generates light L1 from a plasma generated by irradiating a molten metal such as molten tin (Sn) with excitation light, for example. Light L1 includes EUV light at 13.5 nm, which is the same exposure wavelength as the photomask for EUV light, which is the object 50.

[0079] Light L1 generated from the light source 61 passes through the filter 10a. The filter 10a is preferably positioned at the pupil. The filter 10a may change its orientation using the support 20 to adjust the amount of light L1. However, it is preferable to fix the orientation of the filter 10a in order to prevent debris scattered from the molten metal from adhering to the collector mirror 62. The light L1 that has passed through the filter 10a is reflected by the collector mirror 62. The light L1 reflected by the collector mirror 62 travels while being narrowed as converged light and is focused at the focusing position IF. The focusing position IF is positioned conjugate to the upper surface 52 of the object 50.

[0080] The shutter 41 may be inserted near the focusing position IF. In other words, the inspection device 2 may further include a shutter 41 between the collector mirror 62 and the filter 10b to block light L1. When the imaging optical system 70 images the object 50, the shutter 41 is removed from the light beam L2 of light L1. On the other hand, when the imaging optical system 70 does not image the object 50, the shutter 41 may block light L1. This makes it possible to suppress the degradation of the illumination optical system 60 and the imaging optical system 70, including the filter 10b, by light L1.

[0081] Light L1, after passing through the focusing position IF, spreads out as divergent light and enters the filter 10b. The filter 10b is preferably positioned at the pupil. The filter 10b's orientation is changed by the support 20. This adjusts the amount of light L1. In this embodiment, the filter 10a, collector mirror 62, and filter 10b are arranged in order along the direction of light L1's propagation from the light source 61 that emits the light L1. The support 20 changes the orientation of the filter 10b. The support 20 supports the filter 10b in multiple orientations.

[0082] Light L1 that has passed through the filter 10b is incident on a reflecting mirror such as an ellipsoidal mirror 63. The light L1 incident on the ellipsoidal mirror 63 is reflected by the ellipsoidal mirror 63, travels while being focused, and is incident on the recessed mirror 64. The light L1 that is incident on the recessed mirror 64 and reflected is incident on the object 50.

[0083] The ellipsoidal mirror 63 focuses light L1 onto the object 50. The illumination optical system 60 is positioned so that when light L1 illuminates the object 50, the image of the light source 61 is projected onto the upper surface 52 of the object 50. Therefore, the illumination optical system 60 provides critical illumination. In this way, the illumination optical system 60 illuminates the object 50 using critical illumination provided by light L1 generated by the light source 61.

[0084] The object 50 is placed on the stage 55. Light L1 may be incident on the object 50 at an oblique angle as oblique incidence illumination. This allows for bright-field observation. Alternatively, light L1 may be incident from a direction perpendicular to the upper surface 52 of the object 50. This allows for dark-field observation. Light L3, reflected by the object 50, is incident on the perforated concave mirror 71. A hole 71a is provided in the center of the perforated concave mirror 71.

[0085] Light L3 reflected by the perforated concave mirror 71 enters the convex mirror 72. The convex mirror 72 reflects the light L3 that entered from the perforated concave mirror 71 toward the hole 71a of the perforated concave mirror 71. The light L3 that passes through the hole 71a is detected by the detector 73. In this way, the imaging optical system 70 collects the light L3 from the object 50 illuminated by light L1, and the collected light L3 is detected by the detector 73. The light L3 contains information such as defects in the object 50. With this configuration, the inspection device 2 inspects the object 50 for defects and contamination.

[0086] According to this embodiment, the light intensity of the light L1 used as illumination light when inspecting the object 50 can be easily adjusted. For example, even if the illumination light L1 includes EUV light, the light intensity can be easily reduced to an extent that does not damage the pellicle 54. The inspection device 2 of this embodiment can be configured with the configurations of Embodiment 1 and each of its modifications.

[0087] <Embodiment 3> The optical device 3 according to Embodiment 3 will now be described. In the optical device 3 of this embodiment, the orientation of the filter 10 includes a second orientation 32 at a first time step, and a first orientation 31 at a second time step that is later than the first time step. As for the adjustment method of the optical device 3, in step S12 in which the orientation of the filter 10 is changed, the orientation is set to include the second orientation 32 at a first time step, and to include the first orientation 31 at a second time step that is later than the first time step.

[0088] The optical component including the filter 10 may reduce the amount of light L1 traveling along the optical path L0 over time. For example, the filter 10 may degrade due to the influence of transmitted light L1, reducing the amount of light L1 it transmits. In particular, if the light L1 includes EUV light, the filter 10 will degrade due to the influence of EUV light, reducing its transmittance. Therefore, anticipating the degradation of the filter 10, the support unit 20 sets the orientation of the filter 10 to a second orientation 32 at a first time point, which has a lower transmittance than the first orientation 31. Subsequently, at a second time point, the support unit 20 changes the orientation of the filter 10 to a first orientation 31, which has a higher transmittance than the second orientation 32. The second time point may be the time after it is detected that the amount of light L1 transmitted through the filter 10 in the second orientation 32 has fallen below a predetermined standard. Furthermore, the second time point may be the time after a predetermined amount of time has elapsed since the optical device 3 was operated with the filter 10 in the second position 32. The predetermined time may be the operating time determined by experiment or other means until the amount of light L1 transmitted through the filter 10 in the second position 32 falls below a predetermined standard. In this way, the support unit 20 supports the filter 10 in the second position 32 at the first time point, and supports the filter 10 in the first position 31 at the second time point, which is later than the first time point.

[0089] According to this embodiment, the orientation of the filter 10 is changed so that the transmittance increases in response to the decrease in transmittance due to the degradation of the filter 10. Therefore, light L1 can be transmitted at a constant transmittance over a long period of time. Other configurations and effects are described in Embodiments 1 and 2 and their respective modifications.

[0090] While embodiments of the present disclosure have been described above, the disclosure includes appropriate modifications that do not impair its purpose and advantages, and is not limited by the above embodiments. Furthermore, the configurations in Embodiments 1 and 2 and each of their modifications may be combined as appropriate. [Explanation of Symbols]

[0091] 1, 1a, 1b, 1c, 1d, 1e optical equipment 2. Inspection device 10, 10a, 10b filters 11 One side 12 The other side 13 Perpendicular line 14 Edge section 15 Holding part 16 points 20 Support part 30 0th posture 31 1st posture 32 Second posture 33 3rd posture 40 rails 41 shutters 50 Objects 51 Photomasks 52 Top side 53 patterns 54 Pellicle 55 stages 60 Illumination optical system 61 Light source 62 Collector Mirror 63 Ellipsoidal mirror 64 Recessed Mirror 70 Imaging optical system 71. Perforated concave mirror 71a Hole 72 Convex mirror 73 Detectors C Main optical axis IF focusing position L0 optical path L1 light L2 luminous flux L3 Light

Claims

1. A filter placed in the optical path of light including EUV light, the filter having one surface and the other surface facing the first surface, The orientation of the filter is changed so as to change the angle between the perpendicular line of one surface of the filter and the principal optical axis of the light, and a support part capable of supporting the filter in multiple orientations is provided. Equipped with, The filter, when the angle changes, changes in the transmittance of the light passing through the filter. optical equipment.

2. Among the multiple aforementioned postures, The light in the optical path is incident on one of the surfaces of the filter, and the first orientation is such that the angle is a first angle, The light in the optical path is incident on one of the surfaces of the filter, and the second orientation is such that the angle is greater than the first angle, A third orientation in which the light in the optical path does not enter one of the surfaces of the filter, Includes, The optical apparatus according to claim 1.

3. A filter arranged in the optical path of light, the filter having one surface and the other surface facing the first surface, The orientation of the filter is changed so as to change the angle between the perpendicular line of one surface of the filter and the principal optical axis of the light, and a support part capable of supporting the filter in multiple orientations is provided. Equipped with, The filter changes the transmittance of the light passing through it as the angle changes. Among the multiple aforementioned postures, The light in the optical path is incident on one of the surfaces of the filter, and the first orientation is such that the angle is a first angle, The light in the optical path is incident on one of the surfaces of the filter, and the second orientation is such that the angle is greater than the first angle, A third orientation in which the light in the optical path does not enter one of the surfaces of the filter, Includes, optical equipment.

4. A filter arranged in the optical path of light, the filter having one surface and the other surface facing the first surface, The orientation of the filter is changed so as to change the angle between the perpendicular line of one surface of the filter and the principal optical axis of the light, and a support part capable of supporting the filter in multiple orientations is provided. Equipped with, The filter changes the transmittance of the light passing through it as the angle changes. Among the multiple aforementioned postures, The light in the optical path is incident on one of the surfaces of the filter, and the first orientation is such that the angle is a first angle, The light in the optical path is incident on one of the surfaces of the filter, and the second orientation is such that the angle is greater than the first angle, It includes, The support portion supports the filter in the second position at a first time, and supports the filter in the first position at a second time that is later than the first time. optical equipment.

5. The support portion is capable of supporting the filter in the second position while changing the orientation of the filter between the first position and the third position so that the angle changes. The optical apparatus according to claim 2 or 3.

6. The aforementioned support portion is The orientation of the filter is changed using the edge of the filter as a pivot point, or using a point outside the edge of the filter as a pivot point when viewed from the principal optical axis. In the third orientation described above, the filter is positioned outside the luminous beam of light in the optical path. The optical apparatus according to claim 2 or 3.

7. The light in the optical path includes convergent light that is focused toward a predetermined focusing position, or divergent light that is emitted from the predetermined focusing position. The filter, in the second orientation, is tilted towards the light-gathering position compared to the first orientation. The optical apparatus according to any one of claims 2 to 4.

8. The light in the optical path includes convergent light that is focused toward a predetermined focusing position, or divergent light that is emitted from the predetermined focusing position. In the second orientation, the filter is tilted to the opposite side of the light-gathering position compared to the first orientation. The optical apparatus according to any one of claims 2 to 4.

9. The multiple aforementioned orientations are formed by the rotation of the filter with a virtual axis as the axis of rotation. The aforementioned virtual axis penetrates a part of the filter or a part of the holding part that holds the filter, and a part of the light beam. The optical apparatus according to any one of claims 2 to 4.

10. Multiple of the above-mentioned positions are formed by sliding a part of the filter or a part of the holding part that holds the filter along a rail. The optical apparatus according to any one of claims 2 to 4.

11. TP mode for inspecting pellicle-attached masks, NP mode for inspecting masks without pellicles, It has, The support portion supports the filter in the first or second orientation, at least in the case of the TP mode. The optical apparatus according to claim 2.

12. The filter includes a first filter and a second filter, The first filter, the collector mirror, and the second filter are arranged in order along the direction in which the light propagates from the light source that emits the light. The support portion supports the second filter in multiple of the above positions. The optical apparatus according to any one of claims 1 to 4.

13. A shutter for blocking the light is further provided between the collector mirror and the second filter. The optical apparatus according to claim 12.

14. A filter placed in the optical path of light including EUV light, the filter having one surface and the other surface facing the first surface, The orientation of the filter is changed so as to change the angle between the perpendicular line of one surface of the filter and the principal optical axis of the light, and a support part capable of supporting the filter in multiple orientations is provided. A method for adjusting an optical device, including, The steps include: placing the filter in the optical path such that the transmittance of the light passing through the filter changes as the angle changes; The steps include changing the orientation of the filter to one of a plurality of orientations, Equipped with, Method for adjusting optical devices.

15. In the step of changing the orientation of the filter to one of the plurality of orientations, Among the multiple aforementioned postures, The light in the optical path is incident on one of the surfaces of the filter, and the first orientation is such that the angle is a first angle, The light in the optical path is incident on one of the surfaces of the filter, and the second orientation is such that the angle is greater than the first angle, A third orientation in which the light in the optical path does not enter one of the surfaces of the filter, Includes, A method for adjusting an optical device according to claim 14.

16. A filter arranged in the optical path of light, the filter having one surface and the other surface facing the first surface, The orientation of the filter is changed so as to change the angle between the perpendicular line of one surface of the filter and the principal optical axis of the light, and a support part capable of supporting the filter in multiple orientations is provided. A method for adjusting an optical device, including, The steps include: placing the filter in the optical path such that the transmittance of the light passing through the filter changes as the angle changes; The steps include changing the orientation of the filter to one of a plurality of orientations, Equipped with, In the step of changing the orientation of the filter to one of the plurality of orientations, Among the multiple aforementioned postures, The light in the optical path is incident on one of the surfaces of the filter, and the first orientation is such that the angle is a first angle, The light in the optical path is incident on one of the surfaces of the filter, and the second orientation is such that the angle is greater than the first angle, A third orientation in which the light in the optical path does not enter one of the surfaces of the filter, Includes, Method for adjusting optical devices.

17. A filter arranged in the optical path of light, the filter having one surface and the other surface facing the first surface, The orientation of the filter is changed so as to change the angle between the perpendicular line of one surface of the filter and the principal optical axis of the light, and a support part capable of supporting the filter in multiple orientations is provided. A method for adjusting an optical device, including, The steps include: placing the filter in the optical path such that the transmittance of the light passing through the filter changes as the angle changes; The steps include changing the orientation of the filter to one of a plurality of orientations, Equipped with, In the step of changing the orientation of the filter to one of the plurality of orientations, Among the multiple aforementioned postures, The light in the optical path is incident on one of the surfaces of the filter, and the first orientation is such that the angle is a first angle, The light in the optical path is incident on one of the surfaces of the filter, and the second orientation is such that the angle is greater than the first angle, It includes, The support portion supports the filter in the second position at a first time, and supports the filter in the first position at a second time that is later than the first time. Method for adjusting optical devices.

18. In the step of changing the orientation of the filter to one of the plurality of orientations, The support portion is capable of supporting the filter in the second position while changing the orientation of the filter between the first position and the third position so that the angle changes. A method for adjusting an optical device according to claim 15 or 16.

19. The support portion changes the orientation of the filter, using the edge of the filter as a pivot point, or using a point outside the edge of the filter as viewed from the principal optical axis as a pivot point. In the step of changing the orientation of the filter to one of the plurality of orientations, In the third orientation, the support portion positions the filter outside the light beam of the light in the optical path. A method for adjusting an optical device according to claim 15 or 16.

20. The light in the optical path includes convergent light that is focused toward a predetermined focusing position, or divergent light that is emitted from the predetermined focusing position. In the step of changing the orientation of the filter to one of the plurality of orientations, The filter, in the second orientation, is tilted towards the light-gathering position compared to the first orientation. A method for adjusting an optical device according to any one of claims 15 to 17.

21. The light in the optical path includes convergent light that is focused toward a predetermined focusing position, or divergent light that is emitted from the predetermined focusing position. In the step of changing the orientation of the filter to one of the plurality of orientations, In the second orientation, the filter is tilted to the opposite side of the light-gathering position compared to the first orientation. A method for adjusting an optical device according to any one of claims 15 to 17.

22. In the step of changing the orientation of the filter to one of the plurality of orientations, The multiple aforementioned orientations are formed by the rotation of the filter with a virtual axis as the axis of rotation. The aforementioned virtual axis penetrates a part of the filter or a part of the holding part that holds the filter, and a part of the light beam. A method for adjusting an optical device according to any one of claims 15 to 17.

23. In the step of changing the orientation of the filter to one of the plurality of orientations, Multiple of the above-mentioned positions are formed by sliding a part of the filter or a part of the holding part that holds the filter along a rail. A method for adjusting an optical device according to any one of claims 15 to 17.

24. The optical device is TP mode for inspecting pellicle-attached masks, NP mode for inspecting masks without pellicles, It has, In the step of changing the orientation of the filter to one of the plurality of orientations, The support portion supports the filter in the first or second orientation, at least in the case of the TP mode. A method for adjusting an optical device according to claim 15.

25. The filter includes a first filter and a second filter, The first filter, the collector mirror, and the second filter are arranged in order from the light source that emits the light in the direction in which the light propagates. In the step of changing the orientation of the filter to one of the plurality of orientations, The support portion supports the second filter in multiple of the above positions. A method for adjusting an optical device according to any one of claims 14 to 17.

26. The optical device further includes a shutter that blocks the light between the collector mirror and the second filter. A method for adjusting an optical device according to claim 25.

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