Optical system and method

Abstract

An optical system comprising: an optical component configured to modify electromagnetic radiation; and a motor configured to actuate the optical component. The motor includes a mover including a plurality of magnetic components connected to the optical component. The electric motor includes a stator not connected to the mover, the stator including a plurality of electrical components configured to receive an electrical current and thereby interact with a magnetic field of the plurality of magnetic components for contactless actuation of the optical component.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to European application 23192387.1, filed on 21 August 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0003] This invention relates to optical systems and methods. In particular, it relates to the use of electric motors or electric motors for non-contact actuation of optical components. The invention can be used in a variety of optical systems, including but not limited to: photolithography systems, optical measurement systems, and substrate processing systems. Background Technology

[0004] A photolithography apparatus is a machine configured to apply a desired pattern onto a substrate. Photolithography apparatus can be used, for example, in the manufacture of integrated circuits (ICs). A photolithography apparatus can, for example, project a pattern at a patterning device (e.g., a mask) onto a radiation-sensitive material (resist) layer disposed on a substrate.

[0005] To project a pattern onto a substrate, photolithography equipment can use electromagnetic radiation. The wavelength of this radiation determines the minimum size of the feature that can be formed on the substrate. Compared to photolithography equipment using radiation with a wavelength of, for example, 193 nm, photolithography equipment using extreme ultraviolet (EUV) radiation with wavelengths in the range of 4 nm to 20 nm (e.g., 6.7 nm or 13.5 nm) can be used to form smaller features on the substrate. Other photolithography equipment can use other wavelengths. For example, deep ultraviolet (DUV) photolithography equipment can utilize ultraviolet radiation with wavelengths of, for example, 365 nm, 248 nm, 193 nm, 157 nm, or 126 nm.

[0006] Photolithography equipment, as well as other types of optical equipment such as optical measurement equipment and substrate processing equipment, includes optical components that must be actuated during use to perform their functions. It may be desirable to provide an optical system and method that overcomes or mitigates one or more problems associated with the prior art (whether identified herein or elsewhere). Summary of the Invention

[0007] According to a first aspect of this disclosure, an optical system is provided. The optical system includes optical components configured to modify electromagnetic radiation. The optical system includes an electric motor or motor configured to actuate the optical components. The electric motor includes a mover that includes a plurality of magnetic elements connected to the optical components. The electric motor includes a stator not connected to the mover, the stator including a plurality of electrical components configured to receive current and thereby interact with the magnetic field of the plurality of magnetic components for non-contact actuation of the optical components.

[0008] Known optical systems include Lorentz actuators with a flexure arranged to align a pin with a motor. The flexure provides a physical connection between the optical component and the frame. This introduces dynamic stiffness, which is detrimental to the fine and / or rapid actuation of the optical component. The flexure introduces increasing stiffness as the optical component moves and / or vibrates at higher frequencies (e.g., natural or resonant frequencies). This dynamic stiffness undermines the so-called “zero stiffness” concept upon which the Lorentz actuator is based. Furthermore, known Lorentz actuators are relatively large, heavy, and have complex interfaces and connections with the optical component, resulting in considerable power requirements and complex control systems needed to operate them.

[0009] The optical system disclosed herein advantageously eliminates the need for flexures or any other physical contact between the stator and mover. This removes the dynamic stiffness associated with known Lorentz actuators and improves the fine and / or rapid actuation of the optical components, thereby improving the performance of the optical system compared to known optical systems. Compared to known Lorentz actuators, magnetic control provided by multiple magnetic and electrical components advantageously offers a simplified, compact, and lightweight actuation mechanism.

[0010] The number of electrical components can be greater than the number of actuation degrees of freedom of optical components.

[0011] Increasing the numerical aperture of some optical systems is beneficial. For example, lithography apparatuses are typically capable of forming small features at larger numerical apertures. Optical systems with increased numerical apertures can be referred to in the art as super numerical aperture (super NA) optical systems. Super NA optical systems may require larger optical components to capture electromagnetic radiation with large incident angles. To maintain control over the dynamic behavior of the larger optical components (e.g., high-bandwidth natural frequencies or resonant characteristics), it may be necessary to significantly increase the mass of the optical components (e.g., by increasing the thickness of the optical components). For example, it has been predicted that the mass of mirrors in super NA lithography apparatuses will need to be approximately three times larger than that of current non-super NA mirrors to maintain the same dynamic behavior. This increase in mass introduces its own problems and is not considered feasible for all optical systems. For example, the increase in mass can reduce the natural or resonant frequencies of the optical components and thereby introduce unwanted vibrations or movements (e.g., higher-order frequency vibrational modes of the optical components and associated deformations), which may negatively impact the performance of the optical system.

[0012] The optical system disclosed herein advantageously provides additional actuation of optical components (i.e., a system in which the number of actuating elements is greater than the system's actuation degrees of freedom). Multiple magnetic and electrical components can be used to counteract higher-order frequency vibrational modes and associated deformations of the optical components introduced by increasing their size to capture electromagnetic radiation with a wide range of incident angles. This allows the mass of the optical components to remain substantially the same in a super-NA optical system (e.g., achieving the same dynamic behavior without increasing the thickness of the optical components).

[0013] The optical component can be a mirror. The mover can be attached to the back side of the mirror.

[0014] In many optical systems, mirrors are used to modify electromagnetic radiation (e.g., by changing the direction of propagation via reflection). Mirrors can be subjected to unwanted thermal deformation when interacting with electromagnetic radiation, which can negatively impact the performance of the optical system. Electric motors can advantageously actuate optical components to counteract and / or mitigate thermal deformation.

[0015] Optical components can take other forms.

[0016] The optical component can be a transmissive optical component. The optical component can be a lens.

[0017] The optical component can be a diffractive optical component. The optical component can be a diffraction grating.

[0018] Optical components can be polarizing optical components. Optical components can be polarizers.

[0019] Optical components can be configured to modify electromagnetic radiation in one or more ways.

[0020] Optical components can be configured to change the direction of electromagnetic radiation propagation.

[0021] Optical components can be configured to alter the cross-sectional shape (e.g., beam shape) of electromagnetic radiation.

[0022] Optical components can be configured to alter the intensity distribution of electromagnetic radiation.

[0023] Optical components can be configured to alter the phase of electromagnetic radiation.

[0024] Optical components can be configured to refract electromagnetic radiation.

[0025] Optical components can be configured to focus electromagnetic radiation.

[0026] Optical components can be configured to reflect electromagnetic radiation.

[0027] Optical components can be configured to diffract electromagnetic radiation.

[0028] Optical components can be configured to polarize electromagnetic radiation.

[0029] Optical components can be configured to attenuate electromagnetic radiation.

[0030] Optical components can be configured to scatter electromagnetic radiation.

[0031] Optical components can be configured to disperse electromagnetic radiation.

[0032] Optical components can be configured to modify extreme ultraviolet electromagnetic radiation.

[0033] Optical components can be configured to modify deep ultraviolet electromagnetic radiation.

[0034] Optical components can be configured to modify X-ray electromagnetic radiation.

[0035] Optical components can be configured to modify infrared electromagnetic radiation.

[0036] EUV and / or DUV and / or X-ray and / or infrared radiation can be used to perform fine and / or rapid optical processes, such as, for example, EUV lithography, DUV lithography, soft X-ray substrate inspection, or infrared plasma generation in a liquid-generated plasma (LPP) EUV radiation source. Such fine and / or rapid optical processes require correspondingly fine and / or rapid actuation of the optical components. The optical system disclosed herein advantageously improves the actuation accuracy and speed of the optical components, thereby improving the performance of fine and / or rapid optical processes utilizing this optical system.

[0037] The electric motor can be a planar electric motor.

[0038] Compared to known optical systems, planar motors advantageously improve the accuracy of optical component actuation, thereby allowing for fine control of higher-order frequency vibrations and associated deformations of the optical components. Compared to known optical systems, planar motors advantageously improve the speed of optical component actuation, thereby allowing for rapid correction of unwanted movements and / or deformations of the optical components.

[0039] The electric motor can be an inverted planar motor.

[0040] The electric motor can be a three-phase motor.

[0041] The electric motor can be configured to translate the optical component. The electric motor can be configured to translate the optical component in any direction (e.g., along the three vertical axes).

[0042] The electric motor can be configured to rotate the optical component. The electric motor can be configured to rotate the optical component in any direction, for example, around three vertical axes.

[0043] The electric motor can be configured to deform the optical components.

[0044] Multiple magnetic components can be arranged to form a magnetic component array.

[0045] Multiple electrical components can be arranged to form an array of electrical components.

[0046] Providing arrays of magnetic and electrical components advantageously improves the accuracy of actuation control of optical components.

[0047] Multiple magnetic components may include permanent magnets.

[0048] Multiple electrical components may include coils.

[0049] The magnetic component array can be a Halbach magnet array.

[0050] The inventors have discovered that Helbeck magnet arrays provide improved fine and rapid actuation control of optical components.

[0051] An array of electrical components may include multiple layers. The electrical components in the first layer may be arranged perpendicular to the electrical components in the second layer.

[0052] The first layer can be configured to provide actuation of the optical component in a first direction, and the second layer can be configured to provide actuation of the optical component in a second direction perpendicular to the first direction.

[0053] The electric motor can be configured to levitate the optical components.

[0054] Non-contact actuation of optical components via magnetic levitation advantageously avoids the dynamic stiffness associated with known Lorentz actuators, thereby improving the actuation accuracy of optical components compared to known optical systems.

[0055] The stator may include a permanent magnet configured to interact with the magnetic fields of a plurality of magnetic components of the mover and thereby apply a lifting force to the optical components.

[0056] Using gravity compensation with permanent magnets advantageously reduces the power requirements needed to levitate optical components. This, in turn, reduces the thermal load associated with the actuation of optical components and reduces unwanted thermal deformation of optical components, resulting in improved performance of the optical system.

[0057] The inventors have realized that actuation of optical components may not require the long-distance planar motion typically associated with known planar electric motors. Therefore, one or more permanent magnets can be introduced into the stator while maintaining the necessary range of motion for the actuation of the optical components. That is, the inventors have realized that the reduced range of motion requires lower power compared to known planar electric motors, and that gravity compensation using stator permanent magnets can be introduced, which would be impossible with known planar electric motors.

[0058] The permanent magnet of the stator can be nested within one of multiple electrical components.

[0059] The permanent magnet of the stator can replace one of several electrical components.

[0060] The use of permanent magnets nested within electrical components or to replace electrical components with permanent magnets advantageously improves the levitation of optical components without increasing power consumption or compromising the compact arrangement of electrical components in the stator.

[0061] The permanent magnet can be located inside the coil.

[0062] Permanent magnets can occupy the positions of coils in a coil array.

[0063] The permanent magnets of the stator can form part of a stator permanent magnet array, which is arranged to apply a substantially uniform lifting force to the optical components in space.

[0064] The stator permanent magnet array improves the levitation of optical components without increasing power consumption or compromising the compact arrangement of the stator's electrical components.

[0065] The ratio of permanent magnets to electrical components in the stator permanent magnet array can be from about 1 to about 3.

[0066] The inventors have discovered that this ratio is particularly advantageous for improving the levitation of optical components without increasing power consumption or compromising the compact arrangement of the stator's electrical components.

[0067] The stator may include approximately two hundred or more electrical components per square meter.

[0068] The stator may include approximately forty or more electrical components.

[0069] The use of such a large number of electrical components advantageously improves the additional actuation of the optical components. This improves the ability of the electric motor to counteract the higher-order frequency vibration modes and associated deformations of the optical components.

[0070] The mover may include approximately six hundred or more magnetic components per square meter.

[0071] The mover may include approximately 160 or more magnetic components.

[0072] The use of such a large number of magnetic components advantageously improves the additional actuation of the optical components. This improves the motor's ability to counteract the higher-order frequency vibration modes of the optical components and the associated deformation.

[0073] For each electrical component, there may be approximately one or more magnetic components. For each electrical component, there may be approximately four magnetic components or fewer magnetic components.

[0074] The inventors have discovered that these ratios are particularly advantageous for improving additional actuation of optical components without limiting power consumption and associated thermal loads.

[0075] Each magnetic component can occupy an area of ​​approximately 0.04 m by approximately 0.04 m or smaller.

[0076] The inventors have realized that actuation of optical components may not require the long-distance planar motion typically associated with planar electric motors. Therefore, the size of the magnetic component can be significantly reduced compared to the size of known planar electric motors. Using such a small magnetic component advantageously increases the compactness of the mover and facilitates improved additional actuation of the optical component. This improves the motor's ability to counteract the higher-order frequency vibration modes of the optical component and the associated deformation.

[0077] Each electrical component may occupy an area of ​​approximately 0.04 m by approximately 0.12 m or smaller.

[0078] The inventors have realized that actuation of optical components may not require the long-distance planar motion typically associated with planar electric motors. Therefore, the size of the electrical components can be significantly reduced compared to the size of known planar electric motors. Using such small electrical components advantageously increases the compactness of the stator and facilitates improved additional actuation of the optical components. This improves the motor's ability to counteract the higher-order frequency vibration modes of the optical components and the associated deformation.

[0079] The separation distance between adjacent magnetic components can be about 0.04 m or less.

[0080] Such a compact arrangement of the magnetic components advantageously increases the compactness of the mover and facilitates improved additional actuation of the optical components. This improves the motor's ability to counteract the higher-order frequency vibration modes of the optical components and the associated deformation.

[0081] The separation distance between adjacent electrical components can be about 5 mm or less.

[0082] Such a compact arrangement of the electrical components advantageously increases the stator's compactness and facilitates improved additional actuation of the optical components. This improves the motor's ability to counteract the higher-order frequency vibration modes of the optical components and the associated deformation.

[0083] According to a second aspect of this disclosure, a photolithography apparatus is provided, the photolithography apparatus being arranged to project a pattern from a pattern forming apparatus onto a substrate. The photolithography apparatus includes the optical system of the first aspect.

[0084] The optical system can form part of the illumination system.

[0085] The optical system can form part of the projection system.

[0086] The optical system can form part of the radiation source. The optical system can form part of the CO2 beam path in the LPP source.

[0087] The optical system can form part of the measurement system.

[0088] The optical system can form part of a substrate inspection system.

[0089] The optical system can form part of an optical measurement system.

[0090] The optical system can form part of the alignment sensor.

[0091] The optical system can form part of an overlapping sensor.

[0092] The optical system can form part of an optical aberration sensor.

[0093] According to a third aspect of this disclosure, a method for actuating an optical component is provided. The method includes connecting a plurality of magnetic components to the optical component. The method also includes arranging a plurality of electrical components not connected to the optical component. The method further includes providing a current to the plurality of electrical components to thereby interact with the magnetic field of the plurality of magnetic components for non-contact actuation of the optical component.

[0094] The method may include electrical components that provide a number greater than the number of actuation degrees of freedom of the optical components.

[0095] The method may include suspending the optical component.

[0096] The method may include providing a permanent magnet configured to interact with the magnetic field of the plurality of magnetic components and thereby apply a lifting force to the optical component. Attached Figure Description

[0097] Embodiments of the invention will now be described by way of example only with reference to the accompanying schematic drawings, in which:

[0098] - Figure 1 A lithography system according to the present disclosure is described, the lithography system including a lithography apparatus, a radiation source and two electric motors configured to actuate optical components.

[0099] - Figure 2 An optical system according to the present disclosure is schematically depicted, the lithography system including optical components configured to modify electromagnetic radiation and an electric motor configured to actuate the optical components.

[0100] - Figure 3 A flowchart of a method for actuating optical components according to the present disclosure is shown. Detailed Implementation

[0101] Figure 1 A lithography system is schematically depicted, comprising a radiation source SO, a lithography apparatus LA, and two electric motors 120 configured to actuate two different optical components 11 and 13. The radiation source SO is configured to generate an EUV radiation beam B and supply the EUV radiation beam B to the lithography apparatus LA. The lithography apparatus LA includes an illumination system IL, a support structure MT configured to support a pattern forming apparatus MA (e.g., a mask), a projection system PS, and a substrate stage WT configured to support a substrate W.

[0102] The irradiation system IL is configured to adjust the EUV radiation beam B before it is incident on the pattern forming apparatus MA. Additionally, the irradiation system IL may include a faceted field mirror assembly 10 and a faceted pupil mirror assembly 11. Together, the faceted field mirror assembly 10 and the faceted pupil mirror assembly 11 provide the EUV radiation beam B with a desired cross-sectional shape and a desired intensity distribution. Besides or in place of the faceted field mirror assembly 10 and the faceted pupil mirror assembly 11, the irradiation system IL may also include other mirrors or devices. Figure 1In the example, the faceted pupil reflector device 11 is actuated by a motor 120. The motor 120 includes a mover 130, which includes a plurality of magnetic components connected to the faceted pupil reflector device 11. Figure 2 (As shown in the diagram). The motor 120 includes a stator 150 not connected to the rotor 130, and the stator 150 includes a plurality of electrical components ( Figure 2 As shown in the figure, the plurality of electrical components are configured to receive current and thereby interact with the magnetic field of the plurality of magnetic elements for non-contact actuation of the faceted pupil reflector device 11.

[0103] After such adjustment, the EUV radiation beam B interacts with the patterning apparatus MA. As a result of this interaction, a patterned EUV radiation beam B' is generated. A projection system PS is configured to project the patterned EUV radiation beam B' onto a substrate W. For this purpose, the projection system PS may include a plurality of mirrors 13, 14 configured to project the patterned EUV radiation beam B' onto the substrate W held by the substrate stage WT. The projection system PS can apply a reduction factor to the patterned EUV radiation beam B', thus forming an image with features smaller than the corresponding features on the patterning apparatus MA. For example, a reduction factor of 4 or 8 can be applied. Although the projection system PS in Figure 1 The diagram is shown with only two mirrors 13 and 14, but the projection system PS can include a different number of mirrors (e.g., six or eight mirrors). Figure 1 In the example, one of the mirrors 13 of the projection system PS is actuated by a motor 120. The motor 120 includes a mover 130, which includes a plurality of magnetic components connected to the mirror 13. Figure 2 (As shown in the diagram). The motor 120 includes a stator 150 not connected to the rotor 130, and the stator 150 includes a plurality of electrical components ( Figure 2 As shown in the diagram, the plurality of electrical components are configured to receive current and thereby interact with the magnetic field of the plurality of magnetic elements for non-contact actuation of the reflector 13. In the following text and regarding... Figure 2 The electric motor 120 is discussed in more detail. The lithography system may include additional electric motors 120 for non-contact actuation of other optical components therein, such as, for example, optical components of a radiation source SO and / or optical components of an optical measurement system, such as, for example, alignment sensors, level sensors, optical aberration sensors and / or overlap sensors.

[0104] The substrate W may include a previously formed pattern. In this case, the photolithography apparatus LA aligns the image formed by the patterned EUV radiation beam B' with the pattern previously formed on the substrate W.

[0105] A relative vacuum can be provided in the radiation source SO, in the irradiation system IL, and / or in the projection system PS, i.e., a small amount of gas (e.g., hydrogen) at a pressure sufficiently below atmospheric pressure.

[0106] The radiation source SO can be a laser-generated plasma (LPP) source, a discharge-generated plasma (DPP) source, a free-electron laser (FEL) source, or any other radiation source capable of generating EUV radiation.

[0107] Figure 2 An optical system 100 is schematically depicted, including an optical component 110 configured to modify electromagnetic radiation (not shown). Figure 2 In the example, optical component 110 is a mirror. Mirror 110 may, for example, correspond to... Figure 1 One of the mirrors 10 and 11 in the irradiation system of the LA lithography apparatus. As another example, mirror 110 may correspond to... Figure 1 One of the mirrors 13 and 14 in the projection system PS of the LA lithography apparatus. In any of these examples, mirror 110 can be configured to modify extreme ultraviolet (EUV) electromagnetic radiation as part of the EUV lithography process. As another alternative, mirror 110 can correspond to a mirror present in... Figure 1 A mirror (not shown) in the radiation source SO of the lithography apparatus LA. In this example, mirror 110 may be configured to modify infrared radiation as part of plasma and / or EUV radiation generated in a liquid-generated plasma (LPP) EUV radiation source. Optical system 100 may form part of an optical measurement system. For example, optical system 100 may form part of an alignment sensor configured to determine the alignment between substrate W and patterning apparatus MA. As another example, optical system 100 may form part of an overlap sensor configured to determine the overlap error between different layers of substrate W. As another example, optical system 100 may form part of an optical aberration sensor, such as an interferometric wavefront sensor configured to determine the optical aberrations of projection system PS and / or illumination system IL. As another alternative, mirror 110 may not form part of the lithography apparatus and instead form part of another optical system, such as an optical measurement system for substrate inspection. In this example, mirror 110 may be configured to modify X-ray (e.g., soft X-ray) electromagnetic radiation as part of the substrate inspection process. In any of these examples, the reflector 110 can be configured to modify electromagnetic radiation by altering the propagation direction of the electromagnetic radiation via reflection. The reflector 110 can be configured to modify electromagnetic radiation by changing the cross-sectional shape (e.g., beam shape) and / or changing the intensity distribution of the electromagnetic radiation.

[0108] The optical system 100 includes a motor 120 configured to actuate optical components 110. Figure 2 In the example, motor 120 is an inverted planar motor. Motor 120 can be, for example, a three-phase motor. Motor 120 includes a mover 130, which includes a plurality of magnetic components 140 connected to optical component 110. Mover 130 can be formed of a metal such as aluminum. Mover 130 can be formed of a ceramic material. The plurality of magnetic components 140 can be attached to mover 130 by an adhesive such as an adhesive. Figure 2 In this example, the mover 130 is connected to the back side of the reflector 110. The motor 120 includes a stator 150 not connected to the mover 130. The stator 150 includes a plurality of electrical components 160 configured to receive current and thereby interact with the magnetic field of a plurality of magnetic elements 140 for non-contact actuation of the optical component 110. The stator 150 may be formed of a non-ferromagnetic material such as, for example, aluminum. The plurality of magnetic components 140 are arranged to form a magnetic component array, and the plurality of electrical components 160 are arranged to form an electrical component array.

[0109] The magnetic component 140 may include a ferromagnetic material, such as iron. Figure 2 In the example, the magnetic component 140 is a permanent magnet, and the permanent magnet 140 is oriented to have alternating polarities. That is, the south pole S of the first magnet 140 in the magnetic component array is connected to the optical component 110, and the north pole N of the adjacent magnet 140 in the magnetic component array is connected to the optical component 110. The magnets 140 can form a grid array. For example, in Figure 2 Additional columns of the invisible magnets 140 can extend in a direction parallel to the Y-axis. Other arrangements are possible. For example, the array of magnetic components could be a Halback magnet array.

[0110] exist Figure 2 In the example, electrical component 160 includes a coil 160 configured to receive current. The coil 160 is wound around pole 162. The coil 160 may form a grid array. For example, in Figure 2 Additional columns of the invisible coil 160 may extend in a direction parallel to the Y-axis. The array of electrical components may roughly correspond to the array of magnetic components in form and extent. The number of components 140, 160 in each array may differ. The relative positioning of the components 140, 160 in each array may involve in-phase and out-of-phase movement (i.e., movement with alignment and movement without alignment) along the range of the mover 130 and stator 150.

[0111] The array of electrical components may include multiple layers (not shown). For example, a second coil layer may be provided. Figure 2The coil 160 is shown on top of the layer 160. The electrical components 160 in the first layer 160 can be arranged perpendicular to the electrical components 160 in the second layer. Different layers of electrical components 160 can be arranged to control different aspects of the actuation of the optical component 110. For example, the first layer of electrical components 160 can be configured to provide actuation of the optical component 110 in a first direction X, and the second layer of electrical components (not shown) can be configured to provide actuation of the optical component 110 in a second direction Y perpendicular to the first direction X.

[0112] The number of magnetic components 140 and electrical components 160 present in the motor 120 may be selected at least in part depending on the size and / or weight of the optical component 110 and / or the range of desired actuated movement (e.g., translation and / or rotation and / or deformation). The optical component 110 may have a diameter of about 0.1 m or greater. The optical component 110 may have a diameter of about 1 m or less. For example, the optical component 110 may have a diameter of about 0.5 m. The optical component 110 may have a thickness of about 0.05 m or greater. The optical component 110 may have a thickness of about 0.2 m or less. For example, the optical component 110 may have a thickness of about 0.1 m. The optical component 110 may have a weight of about 25 kg or greater. The optical component 110 may have a weight of about 100 kg or less. For example, the optical component 110 may have a weight of about 50 kg. The motor 120 can be configured to translate and / or deform the optical component 110 by a distance of about 0.5 mm or greater. The motor 120 can be configured to translate and / or deform the optical component 110 by a distance of about 2 mm or less. For example, the motor 120 can be configured to translate and / or deform the optical component 110 by a distance of about 1 mm. The motor 120 can be configured to translate and / or deform the optical component 110 by a distance smaller than the size of a single magnetic component 140. The motor 120 can be configured to rotate and / or deform the optical component 110 by an angle of about 0.5 mrad (milliradians) or greater. The motor 120 can be configured to rotate and / or deform the optical component 110 by an angle of about 2 mrad or less. For example, the motor 120 can be configured to rotate and / or deform the optical component 110 by an angle of about 1 mrad.

[0113] The stator 150 may include approximately two hundred electrical components 160 or more per square meter. For example, if the reflector 110 corresponds to... Figure 2 If one of the reflectors 10, 11, 13, and 14 is used, then the stator 150 may include approximately forty electrical components 160 or more. The mover 130 may include approximately six hundred magnetic components 140 or more per square meter. For example, if the reflector 110 corresponds to... Figure 2If one of the reflectors 10, 11, 13, and 14 is used, then the mover 130 may include about one hundred and sixty magnetic components 140 or more. About two or more magnetic components 140 may be present for each electrical component 160. About four or fewer magnetic components 160 may be present for each electrical component 160. For example, about three magnetic components 140 may be present for each electrical component 160. The ratio of magnetic components 140 to electrical components 160 may depend at least in part on the shape and / or extent of the electrical components 160. For example, the electrical component 160 may include a circular coil or an elongated elliptical coil. In the example of a circular coil, a larger number of magnetic components 140 may be present than the number of electrical components 160. In the example of an elongated elliptical coil, the number of magnetic components 140 may be substantially equal to the number of electrical components 160. Each magnetic component 140 may occupy an area of ​​about 0.04 m by about 0.04 m or less. Each electrical component 160 may occupy an area of ​​approximately 0.04 m by approximately 0.12 m or less. The separation distance between adjacent magnetic components 140 (e.g., the pitch of the magnetic component array) may be approximately 0.04 m or less. The pitch of the magnetic component array may be constant. The pitch of the magnetic component array may be substantially equal to the size of a single magnetic component 140. The separation distance between adjacent electrical components 160 (e.g., the pitch of the electrical component array) may be approximately 5 mm or less. The pitch of the electrical component array may be constant. The pitch of the magnetic component array may differ from the pitch of the electrical component array.

[0114] The number of electrical components 160 can be greater than the number of actuation degrees of freedom of optical component 110. For example, if optical component 110 has seven or more degrees of freedom (e.g., three translational degrees of freedom for forward / backward, upward / downward, and left / right movement, three rotational degrees of freedom for yaw, pitch, and roll, and one or more deformation degrees of freedom), then the number of electrical components 160 can be eight or more. This provides additional actuation to optical component 110 (i.e., the number of actuating elements is greater than the number of actuation degrees of freedom). Multiple magnetic components 140 and electrical components 160 can be used to at least partially resolve and / or counteract unwanted effects of higher-order frequency vibration modes and associated movements of optical component 110 that may occur during use. Increasing the number of electrical components 160 can increase the degree of possibility of additional actuation. For example, to achieve twelve actuation degrees of freedom, motor 120 may include approximately forty electrical components 160.

[0115] The motor 120 can be configured to levitate the optical component 110. An electromagnetic force acting between the magnetic component 140 and the electrical component 160 can apply a lifting force 180 to the mover 130 in a substantially vertical direction (i.e., parallel to the Z-axis) against gravity, thereby causing the optical component 110 to levitate above the stator 150. Alternatively or additionally, the stator 150 may include one or more permanent magnets 170 configured to interact with the magnetic fields of the plurality of magnetic components 140 of the mover 130 and thereby apply the lifting force 180 to the optical component 110. Figure 2 In the example shown, only two permanent magnets 170 of the stator 150 are shown, but in practice, more permanent magnets may be present. Figure 2 In the example, the two permanent magnets 170 of the stator 150 are substantially aligned with the two magnetic components 140 of the mover 130. For example, this alignment may occur once every three electrical components 160. The permanent magnets 170 are nested within different coils 160. Alternatively or additionally, the permanent magnets 170 of the stator 150 may replace one of a plurality of electrical components 160. That is, one or more permanent magnets 170 of the stator 150 may be located in positions within the array of electrical components that would otherwise be occupied by electrical components 160. The permanent magnets 170 of the stator 150 may form part of a stator permanent magnet array arranged to apply a substantially uniform lifting force 180 to the optical component 110 in space. The ratio of permanent magnets 170 to electrical components 160 in the stator 150 may be from about 1 to about 3.

[0116] The motor 120 can be configured to actuate the optical component 110 in a variety of ways. The motor 120 can be configured in any direction, for example along the three vertical axes X, Y (which are in...). Figure 2 The optical component 110 is not visible because Y is perpendicular to both the X and Z axes. The motor 120 can be configured to rotate the optical component in any direction, for example, around the three vertical axes X, Y, and Z. For example, when used to actuate the faceted field mirror assembly 10 and / or the faceted pupil mirror assembly 11 (such as...) Figure 1 When used to actuate reflectors 10, 11 (as shown in the diagram), motor 120 can translate and / or rotate reflectors 10, 11 to modify the EUV radiation beam B, thereby giving the beam a desired cross-sectional shape and desired intensity distribution. As another example, when used to actuate PS reflectors 13, 14 (such as those shown in the diagram) in a projection system... Figure 1When the projection system mirrors shown are used, the motor 120 can translate and / or rotate the mirrors 13, 14 to modify the propagation direction of the patterned EUV radiation beam B', so that the patterned EUV radiation beam B' is guided onto the substrate W held by the substrate stage WT. The motor 120 can be configured to deform the optical component 110. For example, any of the mirrors 10, 11, 13, 14 described above may undergo unwanted thermal deformation when interacting with EUV radiation, which may negatively affect the performance of the lithography apparatus LA. The motor 120 can be configured to deform one or more of the mirrors 10, 11, 13, 14 to counteract and / or resolve unwanted thermal deformation, and thereby improve the performance of the lithography apparatus LA.

[0117] When current is supplied to electrical component 160, an electromagnetic force can be generated, which in turn can be used to actuate optical component 110. The generated electromagnetic force can depend at least in part on which electrical components 160 receive current and / or the direction and / or magnitude of the current supplied to electrical components 160. For example, supplying a first current to a first electrical component 160 in a first direction can increase the magnetic field strength in that direction, while supplying a second current to a second electrical component 160 in a second direction can decrease the magnetic field in another direction. This imbalance in the magnetic field can cause mover 130 to move relative to stator 150. As mover 130 moves relative to stator 150, the relative positioning between magnetic component 140 and electrical component 160 changes, which in turn effectively adjusts the magnetic field strength experienced between each of magnetic component 140 and electrical component 160. The current supplied to electrical component 160 can change as mover 130 moves relative to stator 150. For each electrical component 160, a relationship can be established, for example, through analysis and / or numerical modeling, between the direction and magnitude of the current supplied to the electrical component 160 and the resulting electromagnetic force acting on the magnetic component 140 on the mover 130. By establishing this relationship for a variety of different currents and electrical components 160, any desired electromagnetic force and / or torque can be converted into current by considering the inverse of the relationship. Since the relationship depends at least in part on position, the distribution of current throughout the electrical components 160 can be adjusted according to the position of the mover 130 relative to the stator 150. One or more position sensors (not shown) can be provided to measure the position of the mover 130 relative to the stator 150. Measurements performed by one or more position sensors can be used to at least partially determine the supply of current to the electrical components 160 in order to actuate the optical component 110 in a desired manner.

[0118] Compared to known planar electric motors, motor 120 can be considered a lower-power motor 120. For example, compared to a planar electric motor not used to actuate optical components, motor 120 can be configured to provide lower acceleration and / or lower speed and / or lower range of motion for optical components 110. For example, a known planar electric motor can be configured to provide lower acceleration and / or lower speed and / or lower range of motion for optical components 110 in approximately 100 ms. -2 The non-optical component with a mass of approximately 100 kg can move across a distance of approximately 500 mm under acceleration. In contrast, the electric motor 120 of this disclosure can be configured to move in approximately 0.1 ms. -2 An optical component with a mass of about 50 kg moves across a distance of about 1 mm under acceleration.

[0119] Figure 3 A flowchart illustrating a method for actuating an optical component according to the present disclosure is shown. A first step 200 of the method includes connecting a plurality of magnetic components to the optical component. A second step 210 of the method includes arranging a plurality of electrical components not connected to the optical component. A third step 220 of the method includes providing current to the plurality of electrical components to thereby interact with the magnetic fields of the plurality of magnetic elements for non-contact actuation of the optical component. The method may optionally include the step of providing a number of electrical components greater than the number of actuation degrees of freedom of the optical component. The method may optionally include the step of levitizing the optical component. The method may optionally include the step of providing a permanent magnet configured to interact with the magnetic fields of the plurality of magnetic components and thereby apply a lifting force to the optical component.

[0120] Optical component 110 has been described and depicted to date as a mirror. However, it should be understood that optical component 110 may take other forms, and an electric motor may be used to actuate and / or suspend any given optical component that needs to be actuated without contact. The optical component may be a transmissive optical component, such as, for example, a lens. The optical component may be a diffractive optical component, such as, for example, a diffraction grating. The optical component may be a polarizing optical component, such as, for example, a polarizer.

[0121] Optical component 110 has been described and depicted to date as modifying electromagnetic radiation by reflecting it to alter its propagation direction. However, it should be understood that optical component 110 can take other forms and can be configured to modify electromagnetic radiation in other ways. For example, optical component 110 can be configured to change the propagation direction of electromagnetic radiation via refraction. Optical component 110 can be configured to change the phase of electromagnetic radiation. Optical component 110 can be configured to diffract electromagnetic radiation. Optical component 110 can be configured to polarize electromagnetic radiation. Optical component 110 can be configured to attenuate electromagnetic radiation. Optical component 110 can be configured to scatter electromagnetic radiation. Optical component 110 can be configured to disperse electromagnetic radiation. Generally, the electric motor 120 described herein can be used for non-contact actuation of any optical component configured to modify electromagnetic radiation in any given manner.

[0122] While specific references can be made to the use of lithography equipment in IC manufacturing herein, it should be understood that the lithography equipment described herein may have other applications. Possible other applications include manufacturing integrated optical systems, guiding and detecting patterns for magnetic domain memories, flat panel displays, liquid crystal displays (LCDs), thin-film magnetic heads, etc.

[0123] While embodiments of the invention are specifically referred to herein in the context of photolithography equipment, these embodiments can be used in other equipment. Embodiments of the invention can form components of any equipment used for mask inspection, metrology, or measuring or processing objects such as wafers (or other substrates) or masks (or other patterning apparatus). These devices are generally referred to as photolithography tools. Such photolithography tools can use vacuum conditions or ambient (non-vacuum) conditions.

[0124] While specific reference has been made to the use of embodiments of the invention in the context of optical lithography, it should be understood that the invention is not limited to optical lithography and can be used in other applications (e.g., imprint lithography) where circumstances permit. While specific reference has been made to the use of embodiments of the invention in the context of EUV lithography, it should be understood that the optical systems of this disclosure can form portions of other types of lithography apparatuses (such as deep ultraviolet (DUV) lithography apparatuses) using ultraviolet radiation with wavelengths of, for example, 365 nm, 248 nm, 193 nm, 157 nm, or 126 nm.

[0125] Where circumstances permit, embodiments of the invention may be implemented in hardware, firmware, software, or any combination thereof. Embodiments of the invention may also be implemented as instructions stored on a machine-readable medium, which may be read and executed by one or more processors. A machine-readable medium may include any means for storing or transmitting information in a form readable by a machine (e.g., a computing device). For example, a machine-readable medium may include: read-only memory (ROM); random access memory (RAM); magnetic storage media; optical storage media; flash memory devices; propagated signals in electrical, optical, acoustic, or other forms (e.g., carrier waves, infrared signals, digital signals, etc.), etc. Furthermore, firmware, software, routines, and instructions may be described herein as performing certain actions. However, it should be understood that such descriptions are for convenience only, and these actions are actually caused by a computing device, processor, controller, or other means that execute firmware, software, routines, instructions, etc., and in performing such operations, enable actuators or other devices to interact with the physical world.

[0126] While specific embodiments of the invention have been described above, it should be understood that the invention can be practiced in other ways than those described. The above description is intended to be illustrative and not restrictive. Therefore, those skilled in the art will understand that modifications can be made to the described invention without departing from the scope of the claims set forth below.

Claims

1. An optical system, comprising: An optical component configured to modify electromagnetic radiation; and An electric motor configured to actuate the optical component, wherein the electric motor comprises: A mover, the mover comprising a plurality of magnetic components connected to the optical component; and A stator not connected to the mover, the stator comprising a plurality of electrical components configured to receive current and thereby interact with the magnetic field of the plurality of magnetic elements for non-contact actuation of the optical components.

2. The optical system according to claim 1, wherein, The number of electrical components is greater than the number of actuation degrees of freedom of the optical components.

3. The optical system according to claim 1 or claim 2, wherein, The optical component is a reflector and the mover is connected to the back side of the reflector.

4. The optical system according to any of the preceding claims, wherein, The optical component is configured to modify one of the following: Extreme ultraviolet electromagnetic radiation; Deep ultraviolet electromagnetic radiation; X-ray electromagnetic radiation; or Infrared electromagnetic radiation.

5. The optical system according to any of the preceding claims, wherein, The electric motor is a planar electric motor.

6. The optical system according to any of the preceding claims, wherein, The plurality of magnetic components are arranged to form a magnetic component array, and the plurality of electrical components are arranged to form an electrical component array.

7. The optical system according to claim 6, wherein, The magnetic component array is a Heilbeck magnet array.

8. The optical system according to claim 6 or claim 7, wherein, The array of electrical components includes multiple layers, wherein the electrical components of the first layer are arranged perpendicular to the electrical components of the second layer.

9. The optical system according to any of the preceding claims, wherein, The electric motor is configured to levitate the optical component.

10. The optical system according to any of the preceding claims, wherein, The stator includes a permanent magnet configured to interact with the magnetic field of the plurality of magnetic components of the mover and thereby apply a lifting force to the optical components.

11. The optical system according to claim 10, wherein, The permanent magnet of the stator is nested within one of the plurality of electrical components. Alternatively, the permanent magnet of the stator may replace one of the plurality of electrical components.

12. The optical system according to claim 10 or claim 11, wherein, The permanent magnets of the stator form part of a stator permanent magnet array, which is arranged to apply a substantially uniform lifting force to the optical component in space.

13. The optical system according to claim 12, wherein, The ratio of permanent magnets to electrical components in the stator permanent magnet array is approximately 1 to approximately 3.

14. The optical system according to any of the preceding claims, wherein, The stator comprises approximately two hundred or more electrical components per square meter.

15. The optical system according to any of the preceding claims, wherein, The mover comprises approximately six hundred or more magnetic components per square meter.

16. The optical system according to any of the preceding claims, wherein, For each electrical component, there are between approximately one and approximately four magnetic components.

17. The optical system according to any of the preceding claims, wherein, Each magnetic component occupies an area of ​​approximately 0.04 m by approximately 0.04 m or smaller.

18. The optical system according to any of the preceding claims, wherein, Each electrical component occupies an area of ​​approximately 0.04 m by approximately 0.12 m or smaller.

19. The optical system according to any of the preceding claims, wherein, The separation distance between adjacent magnetic components is approximately 0.04 m or less.

20. The optical system according to any of the preceding claims, wherein, The separation distance between adjacent electrical components is approximately 5 mm or less.

21. A photolithography apparatus arranged to project a pattern from a pattern forming apparatus onto a substrate, the photolithography apparatus comprising an optical system according to any of the preceding claims.

22. A method for actuating an optical component, comprising: Connect multiple magnetic components to the optical component; Arrange multiple electrical components that are not connected to the optical components; and Current is supplied to the plurality of electrical components so that they interact with the magnetic field of the plurality of magnetic elements for non-contact actuation of the optical components.

23. The method of claim 22, further comprising providing an electrical component in a number greater than the number of actuation degrees of freedom of the optical component.

24. The method of claim 22 or claim 23, comprising suspending the optical component.

25. The method according to any one of claims 22 to 24, comprising: A permanent magnet is provided, which is configured to interact with the magnetic field of the plurality of magnetic components and thereby apply a lifting force to the optical component.

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