Aberration correction in metrology systems

Abstract

Metrology systems and methods are described. In these systems and methods, one or more metasurfaces are used to correct aberrations caused by optical element (s) (e.g., lenses, beam splitters, mirrors, refractive or diffractive optical components, etc. A metasurface (also referred to as a superlens) is an array of relatively thin 2D planar surface structures configured to modify the trajectory, amplitude, phase, polarization, and / or other characteristics of the incident beam. The one or more metasurfaces are configured to replace, for example, one or more refractive elements, diffractive elements, and / or moving stages previously used for aberration correction in existing metrology systems. This makes this metrology system more compact, lighter and cheaper than existing systems, among other advantages.

Description

Cross-reference to related applications

[0001] This application claims priority to U.S. Application 63 / 543,884, filed October 12, 2023, which is incorporated herein by reference in its entirety. Technical Field

[0002] This description relates to aberration correction in measurement systems. Background Technology

[0003] Photolithography projection apparatuses can be used, for example, in the manufacture of integrated circuits (ICs). Patterning apparatus (e.g., a mask) can include or provide a pattern (“design layout”) corresponding to an individual layer of the IC, and this pattern can be transferred onto a target portion (e.g., comprising one or more dies) on a substrate (e.g., a silicon wafer) coated with a layer of radiation-sensitive material (“resist”) by methods such as pattern radiating target portions through the patterning apparatus. Typically, a single substrate comprises multiple adjacent target portions, and the pattern is sequentially transferred onto the target portions by the photolithography projection apparatus, one target portion at a time.

[0004] Before a pattern is transferred from a patterning apparatus to a substrate, the substrate may undergo various processes, such as primer coating, resist coating, and soft baking. After exposure, the substrate may undergo other processes (“post-exposure processes”), such as post-exposure baking (PEB), development, hard baking, and measurement / inspection of the transferred pattern. This array of processes is used as the basis for manufacturing individual layers of a device (e.g., an IC). The substrate may then undergo various processes, such as etching, ion implantation (doping), metallization, oxidation, deposition, chemical mechanical polishing, etc., all aimed at completing the individual layers of the device. If several layers are required in the device, the entire process or its variations are repeated for each layer. Ultimately, the device will be present in each target portion on the substrate. These devices are then separated from each other by techniques such as dicing or sawing, allowing the individual devices to be mounted on a carrier, connected to pins, etc.

[0005] The manufacturing process of this equipment can be considered a patterning process. A patterning process involves patterning steps, such as optical and / or nanoimprint lithography using patterning equipment in a lithography apparatus to transfer a pattern on the patterning equipment onto a substrate, and the patterning process typically, but optionally, involves one or more related patterning steps, such as resist development by a developing apparatus, baking the substrate using a baking tool, etching using an etching apparatus, deposition, etc.

[0006] Photolithography is a core step in manufacturing devices such as integrated circuits (ICs), in which patterns formed on a substrate define the functional elements of the device, such as microprocessors and memory chips. Similar photolithography techniques are also used in the fabrication of flat panel displays, microelectromechanical systems (MEMS), and other devices.

[0007] As semiconductor manufacturing processes continue to advance, the size of functional components has been continuously reduced, while the number of functional components (such as transistors) in each device has been steadily increasing over the decades, following a trend commonly known as "Moore's Law." In the current state of technology, the layers of the device are fabricated using photolithography projection devices, which use irradiation from a deep ultraviolet light source to project the design layout onto a substrate, thereby creating individual functional components with dimensions well below 100 nm (i.e., less than half the wavelength of radiation from the irradiation source, such as a 193 nm source).

[0008] According to the resolution formula CD = k1 × λ / NA, the process of printing features with dimensions smaller than the classical resolution limit of a photolithography projection apparatus is often referred to as low-k1 lithography, where λ is the wavelength of the radiation used (currently 248 nm or 193 nm in most cases), NA is the numerical aperture of the projection optics in the photolithography projection apparatus, CD is the "critical size," typically the smallest feature size to be printed, and k1 is an empirical resolution factor. Generally, the smaller k1 is, the more difficult it becomes to reproduce patterns on the substrate that are similar in shape and size to those desired by the designer to achieve specific electrical functions and performance. To overcome these difficulties, complex fine-tuning steps are applied to the photolithography projection apparatus, design layout, or patterning equipment. These fine-tuning steps include, but are not limited to: optimization of NA and optical coherence settings, custom illumination schemes, use of phase-shifting patterning equipment, optical proximity correction (OPC, sometimes also called "optical and process correction") in the design layout, or other methods generally defined as "resolution enhancement techniques" (RET). Accurate measurement (e.g., measurement of critical dimensions, alignment and / or overlay between layers of a patterned substrate) is key to these resolution enhancement techniques. Summary of the Invention

[0009] Measurement systems and methods are described. In these systems and methods, one or more metasurfaces are used to correct aberrations caused by optical elements(e.g., lenses, beam splitters, mirrors, refractive or diffractive optical components, etc.). A metasurface (also referred to as a metalens) is a relatively thin array of 2D planar surface structures configured to modify the trajectory, amplitude, phase, polarization, and / or other properties of an incident beam. One or more metasurfaces are configured to replace, for example, one or more refractive elements, diffractive elements, and / or a moving stage previously used for aberration correction in existing measurement systems. Among other advantages, this makes the measurement system more compact, lighter, and less expensive than existing systems.

[0010] According to one embodiment, a measurement system associated with semiconductor manufacturing is provided. The system includes optical elements configured to receive and transmit an incident radiation beam. The optical elements induce aberrations in the incident radiation beam. These aberrations include undesired changes to target characteristics of the incident radiation beam. The system includes one or more metasurfaces configured to reverse these changes to correct for the aberrations induced by the optical elements.

[0011] In some embodiments, one or more metasurfaces comprise an array of metasurfaces. In some embodiments, the array of metasurfaces comprises a two-dimensional (2D) array of metasurfaces. In some embodiments, each metasurface comprises a nanoantenna, a meta-atom, or a nanoparticle. In some embodiments, one or more metasurfaces are active. In some embodiments, one or more metasurfaces are passive.

[0012] In some embodiments, the calibrated radiation beam is configured to be used in the illumination branch of the measurement system to illuminate a measurement target on a patterned substrate, and / or used by a detector in the detection branch of the measurement system to generate a measurement detection signal.

[0013] In some embodiments, aberrations include chromatic aberration, spherical aberration, and / or coma. In some embodiments, aberrations include lateral chromatic aberration.

[0014] In some embodiments, undesirable changes to the target characteristics of the incident radiation beam include deflection of the incident radiation beam due to changes in wavelength. One or more metasurfaces are configured to guide the incident radiation beam back to the target position, which helps eliminate the mechanical movement required for the stage of the measurement system. In some embodiments, undesirable changes include changes in the trajectory of the incident radiation beam away from the target focus. One or more metasurfaces are configured to redirect the incident radiation beam back to the target focus.

[0015] In some embodiments, one or more metasurfaces are positioned in front of the optical element along the optical path of the incident radiation beam. In some embodiments, one or more metasurfaces are positioned behind the optical element along the optical path of the incident radiation beam.

[0016] In some embodiments, the optical elements include lenses, beam splitters, mirrors, and / or refractive or diffractive optical components.

[0017] In some embodiments, one or more metasurfaces are configured to replace one or more refractive elements, diffractive elements, and / or a moving stage previously used for aberration correction in a measurement system.

[0018] In some embodiments, one or more metasurfaces are configured to modify the amplitude, phase, and / or polarization of the incident radiation beam.

[0019] In some embodiments, the measurement system includes a radiation source. The radiation source is configured to generate an incident radiation beam. In some embodiments, the measurement system includes a detector. The detector is configured to receive diffracted first-order or higher-order radiation from a measurement target. The measurement target diffracts the incident radiation beam before or after optical elements induce aberrations and one or more metasurfaces reverse changes in target properties to correct for the aberrations. The detector is also configured to generate a detection signal.

[0020] In some embodiments, optical elements and one or more metasurfaces form part of an alignment sensor and / or an overlay detection sensor. In some embodiments, the alignment sensor and / or overlay detection sensor are configured for use on a semiconductor wafer and are used in a semiconductor manufacturing process.

[0021] According to another embodiment, a measurement method is provided. The method includes one or more of the operations described above, performed by a measurement system. Attached Figure Description

[0022] The above aspects, as well as other aspects and features, will become apparent to those skilled in the art after reviewing the following description of specific embodiments in conjunction with the accompanying drawings.

[0023] Figure 1 A photolithography apparatus according to one embodiment is schematically depicted.

[0024] Figure 2 An embodiment of a lithography unit or cluster according to one embodiment is illustrated schematically.

[0025] Figure 3 An example measurement system according to one embodiment is schematically depicted.

[0026] Figure 4 An example measurement technique according to one embodiment is illustrated schematically.

[0027] Figure 5 The diagram illustrates the relationship between the radiation spot and the measurement target of a measurement system according to one embodiment.

[0028] Figure 6 The illustration depicts a measurement system comprising one or more metasurfaces according to one embodiment, the one or more metasurfaces being configured to correct aberrations in an incident radiation beam.

[0029] Figure 7 An example metasurface according to one embodiment is illustrated.

[0030] Figure 8 The illustration shows a side view of the incident radiation beam, optical elements (lens in this example), and lateral chromatic aberration according to one embodiment.

[0031] Figure 9 The illustration shows a diagram from one embodiment. Figure 8 It has the same incident radiation beam and optical elements, but has a side view of one or more metasurfaces configured to correct lateral chromatic aberration.

[0032] Figure 10 The figure illustrates a measurement method according to one embodiment.

[0033] Figure 11 This is a block diagram of an example computer system according to one embodiment. Detailed Implementation

[0034] In semiconductor device manufacturing, metrology operations typically involve determining the location of a measurement target (or multiple targets) and / or other targets within layers of the semiconductor device structure. This location is usually determined by irradiating the measurement target with radiation and comparing the characteristics of different diffraction orders of the radiation reflected from the target. Such techniques are used to measure overlay, alignment, and / or other parameters.

[0035] Existing metrology systems use one or more bulky multi-element assemblies to correct chromatic aberration in radiation. These assemblies may include multiple refractive (e.g., positive and negative doublet lenses) and / or diffractive (e.g., Fresnel lenses) optics with opposite dispersion slopes, a moving stage, and / or other components. These assemblies increase the cost and size of a typical metrology system (e.g., a three-element lens assembly with a base has a relatively large footprint), have inherent material property limitations (such as dispersion inherent in glass), have moving parts, and sometimes still cannot fully correct aberrations, among other drawbacks. For example, correction assemblies in existing metrology systems may include multiple correction crowns or flint glass lenses for color correction, resulting in higher commodity costs, weight, and volume of metrology systems. The optical design of these assemblies for chromatic aberration correction is fundamentally limited by the dispersive properties of glass and the surface shape of the optical elements, often resulting in some residual aberrations that are difficult to correct using conventional methods. Furthermore, the mechanical movement of the objective lens or other lens assembly used for chromatic aberration correction is time-consuming (which affects production volume) and requires mechatronic components (which further increases the commodity cost, weight and size of the measurement system and shortens the machine's lifespan).

[0036] In the systems(s) described herein, one or more metasurfaces are used to correct aberrations. The bulky multi-element assemblies used in existing metrology systems to correct chromatic radiation are eliminated. Metasurfaces are two-dimensional (2D) arrays of custom-designed subwavelength nanoantennas (also known as metaatoms) capable of modifying the amplitude, phase, and polarization of the incident radiation beam. Custom engineering of metaatoms facilitates the use of unconventional materials (e.g., materials other than glass) at the subwavelength thickness scale. Because one or more metasurfaces are used instead of bulky multi-element assemblies, this metrology system is more powerful, more compact, lighter, and less expensive than existing systems, among other advantages.

[0037] For example, aberration correction (which is not limited to chromatic aberration correction, but also includes spherical aberration, coma, and / or other aberration correction) is achieved by engineering the optical response of one or more metasurfaces (e.g., controlling the effective refractive index, unit cell geometry, phase, amplitude, and polarization, etc.). One or more metasurfaces reduce the volume and mass of metrology systems by shrinking the footprint of optical devices from three dimensions (which are bulkier) to two dimensions (e.g., with subwavelength thickness), improving the commodity cost of metrology systems (e.g., at least due to lower material, handling, and transportation costs), and increasing the productivity of metrology processes (e.g., by achieving denser integration, parallel operation, and faster scanning within a given volume, due to reduced mass). Furthermore, through engineered dispersion, polarization response, light attenuation, and phase control, one or more metasurfaces provide new functionalities beyond those achievable with conventional optical elements and their conventional optical materials (e.g., FS, Si, etc.).

[0038] The following description, presented in a concise manner, pertains to semiconductor device manufacturing and patterning processes. Several components of systems and / or methods for semiconductor device measurement are also described in the following paragraphs. These systems and methods can be used, for example, to measure overlays, alignments, etc., in semiconductor device manufacturing processes, or for other operations.

[0039] While this document may specifically refer to measurements of overlay, alignment, or other parameters, and the fabrication of integrated circuits (ICs) for semiconductor devices, it should be understood that the description herein has many other applications. For example, it can be used in the fabrication of integrated optical systems, the patterning and detection of magnetic domain memories, display panels, thin-film magnetic heads, and the like. Those skilled in the art will understand that, in the context of such alternative applications, any use of the terms “mask,” “wafer,” or “die” herein should be considered interchangeable with the more general terms “mask,” “substrate,” and “target portion,” respectively.

[0040] Figure 1An embodiment of a photolithography apparatus LA is schematically depicted. The apparatus includes: an irradiation system (irradiator) IL configured to modulate a radiation beam B (e.g., UV radiation, DUV radiation, or EUV radiation); a support structure (e.g., a mask stage) MT configured to support a patterning apparatus (e.g., a mask) MA and connected to a first positioner PM configured to accurately position the patterning apparatus according to certain parameters; a substrate stage (e.g., a wafer stage) WT (e.g., WTa, WTb, or both), configured to hold a substrate (e.g., a resist-coated wafer) W and coupled to a second positioner PW configured to accurately position the substrate according to certain parameters; and a projection system (e.g., a refractive projection lens system) PS configured to project a pattern imparted by the radiation beam B by the patterning apparatus MA onto a target portion C (e.g., comprising one or more dies and commonly referred to as a field) of the substrate W. The projection system is supported on a reference frame RF. As shown in the figure, the device is transmissive (e.g., using a transmissive mask). Alternatively, the device may be reflective (e.g., using a programmable mirror array or a reflective mask).

[0041] The irradiator IL receives the radiation beam from the radiation source SO. For example, when the source is an excimer laser, the source and the lithography apparatus can be separate entities. In such cases, the source is not considered part of the lithography apparatus, and the radiation beam is delivered from the source SO to the irradiator IL via a beam delivery system BD (including, for example, suitable guide mirrors and / or beam expanders). In other cases, such as when the source is a mercury lamp, the source can be an integral part of the apparatus. The source SO and the irradiator IL, together with the desired beam delivery system BD, can be collectively referred to as the radiation system.

[0042] The illuminator IL can alter the intensity distribution of the beam. The illuminator can be arranged to limit the radial range of the radiation beam such that the intensity distribution is non-zero within an annular region in the pupil plane of the illuminator IL. Additionally or alternatively, the illuminator IL can be operable to limit the beam distribution in the pupil plane such that the intensity distribution is non-zero in multiple equally spaced sectors within the pupil plane. The intensity distribution of the radiation beam in the pupil plane of the illuminator IL can be referred to as the illumination mode.

[0043] An illuminator IL may include an adjuster AD configured to adjust the (angular / spatial) intensity distribution of the beam. Typically, at least the outer and / or inner radial ranges of the intensity distribution in the pupil plane of the illuminator (typically referred to as σ-outer and σ-inner, respectively) can be adjusted. The illuminator IL may be operable to change the angular distribution of the beam. For example, the illuminator may be operable to change the number and angular range of sectors in the pupil plane where the intensity distribution is non-zero. Different illumination modes can be achieved by adjusting the intensity distribution of the beam in the pupil plane of the illuminator. For example, by limiting the radial and angular ranges of the intensity distribution in the pupil plane of the illuminator IL, the intensity distribution can have a multipole distribution, such as a dipole, tetrapole, or hexapole distribution. The desired illumination mode can be obtained, for example, by inserting an optics providing the illumination mode into the illuminator IL or by using a spatial light modulator.

[0044] The illuminator IL is operable to change the polarization of the beam and operable to adjust the polarization using an adjuster AD. The polarization state of the radiation beam across the pupil plane of the illuminator IL can be referred to as the polarization mode. The use of different polarization modes can allow for greater contrast in the image formed on the substrate W. The radiation beam can be unpolarized. Alternatively, the illuminator can be arranged to linearly polarize the radiation beam. The polarization direction of the radiation beam can vary across the pupil plane of the illuminator IL. The polarization direction of the radiation can be different in different regions of the pupil plane of the illuminator IL. The polarization state of the radiation can be selected depending on the illuminator mode. For multi-pole illuminator modes, the polarization of each pole of the radiation beam can generally be substantially perpendicular to the position vector of that pole in the pupil plane of the illuminator IL. For example, for dipole illuminator modes, the radiation can be linearly polarized in a direction substantially perpendicular to the line bisects the two opposing sectors of the dipole. The radiation beam can be polarized in one of two different orthogonal directions, which can be referred to as the X-polarization state and the Y-polarization state. For quadrupole illumination, the radiation in the sector of each pole can be linearly polarized in a direction substantially perpendicular to the line bisecting the sector. This polarization mode can be called XY polarization. Similarly, for hexapole illumination, the radiation in the sector of each pole can be linearly polarized in a direction substantially perpendicular to the line bisecting the sector. This polarization mode can be called TE polarization.

[0045] Furthermore, the irradiator IL typically includes various other components, such as an integrator IN and a beam concentrater CO. The irradiation system may include various types of optical components for guiding, shaping, or controlling radiation, such as refractive, reflective, magnetic, electromagnetic, electrostatic, or other types of optical components, or any combination thereof. Thus, the irradiator provides a regulated radiation beam B, which has a desired uniformity and intensity distribution in its cross-section.

[0046] The support structure (MT) supports the patterning apparatus in a manner dependent on the orientation of the patterning apparatus, the design of the lithography device, and other conditions, such as whether the patterning apparatus is held in a vacuum environment. The support structure can use mechanical, vacuum, electrostatic, or other clamping techniques to hold the patterning apparatus. The support structure can be, for example, a frame or stage that can be fixed or moved as needed. The support structure ensures that the patterning apparatus is, for example, in the desired position relative to the projection system. Any use of the term "mask" or "mask" herein is to be considered synonymous with the more general term "patterning apparatus".

[0047] The term "patterning apparatus" as used herein should be interpreted broadly to refer to any apparatus that can be used to impart a pattern to a target portion of a substrate. In one embodiment, a patterning apparatus is any apparatus that can be used to impart a pattern to a radiation beam in a cross section to create a pattern in the target portion of the substrate. It should be noted that, for example, if the pattern includes phase-shifting features or so-called auxiliary features, the pattern imparted to the radiation beam may not correspond precisely to the desired pattern in the target portion of the substrate. Typically, the pattern imparted to the radiation beam will correspond to a specific functional layer in a device (such as an integrated circuit) being created in the target portion of the substrate.

[0048] Patterning apparatus can be transmissive or reflective. Examples of patterning apparatus include masks, programmable mirror arrays, and programmable LCD panels. Masks are well-known in photolithography and include mask types such as binary, alternating phase-shift, and attenuation phase-shift masks, as well as various hybrid mask types. Examples of programmable mirror arrays employ a matrix arrangement of small mirrors, each of which can be individually tilted to reflect incoming radiation beams in different directions. The tilted mirrors impart a pattern to the radiation beam, which is reflected by the mirror matrix.

[0049] The term "projection system" should be interpreted broadly to encompass any type of projection system, including refractive, reflective, reflective-refractive, magnetic, electromagnetic, and electrostatic optical systems, or any combination thereof, depending on the exposure radiation used or the requirements of other factors such as the use of immersion liquids or vacuum. Any use of the term "projection lens" in this document may be considered synonymous with the more general term "projection system".

[0050] The projection system PS may include multiple optical (e.g., lens) elements and may also include an adjustment mechanism configured to adjust one or more optical elements to correct for aberrations (phase changes across the field and pupil plane). To achieve this, the adjustment mechanism may be operable to manipulate one or more optical (e.g., lens) elements within the projection system PS in one or more different ways. The projection system may have a coordinate system in which its optical axis extends in the z-direction. The adjustment mechanism may be operable to perform any combination of the following: offsetting one or more optical elements; tilting one or more optical elements; and / or deforming one or more optical elements. The displacement of the optical elements may be in any direction (x, y, z, or a combination thereof). Tilt of the optical elements is typically achieved by rotating about axes in the x and / or y directions, thereby deviating from a plane perpendicular to the optical axis, although rotation about the z-axis may also be used for non-rotationally symmetric aspherical optical elements. The deformation of the optical elements may include low-frequency shapes (e.g., astigmatism) and / or high-frequency shapes (e.g., free-form aspherical surfaces). Deformation of an optical element can be performed, for example, by applying forces to one or more sides of the optical element using one or more actuators and / or by heating one or more selected areas of the optical element using one or more heating elements. Typically, it may be impossible to adjust the projection system PS to correct apodization (transmission variation across the pupil plane). When designing a patterning apparatus (e.g., a mask) MA for a lithography device LA, a transmission map of the projection system PS can be used. Using computational lithography techniques, the patterning apparatus MA can be designed to at least partially correct apodization.

[0051] Photolithography apparatuses can be of the type having two stages (dual stages) or more stages (e.g., two or more substrate stages WTa, WTb; two or more patterning equipment stages; substrate stage WTa and stage WTb below the projection system that does not have a substrate, stage WTb being dedicated to, for example, facilitating measurement and / or cleaning). In such multi-stage machines, additional stages can be used in parallel, or preparation steps can be performed on one or more stages while one or more other stages are used for exposure. For example, alignment measurements can be performed using an alignment sensor AS and / or level (height, tilt, etc.) measurements can be performed using a level sensor LS.

[0052] In the operation of the photolithography apparatus LA, the radiation beam is regulated and provided by the irradiation system IL. The radiation beam B is incident on a patterning apparatus (e.g., a mask) MA held on a support structure (e.g., a mask stage) MT and is patterned by the patterning apparatus. After passing through the patterning apparatus MA, the radiation beam B is passed through a projection system PS, which focuses the beam onto a target portion C of the substrate W. With the aid of a second positioner PW and a position sensor IF (e.g., an interferometer, linear encoder, 2D encoder, or capacitive sensor), the substrate stage WT can be accurately moved, for example, to position different target portions C within the path of the radiation beam B. Similarly, a first positioner PM and another position sensor (which is located in…)… Figure 1 (Not explicitly depicted) can be used, for example, to accurately position the patterning apparatus MA relative to the path of the radiation beam B, either after mechanical acquisition from the mask library or during scanning. Typically, movement of the support structure MT can be achieved using long-stroke modules (coarse positioning) and short-stroke modules (fine positioning), which form part of the first positioner PM. Similarly, movement of the substrate stage WT can be achieved using long-stroke and short-stroke modules forming part of the second positioner PW. In the case of a stepper (as opposed to a scanner), the support structure MT can be connected only to the short-stroke actuator, or it can be fixed. The patterning apparatus MA and the substrate W can be aligned using the patterning apparatus with alignment marks M1, M2 and substrate alignment marks P1, P2. Although the illustrated substrate alignment marks occupy dedicated target portions, they can be located in the space between the target portions (these are called scribing alignment marks). Similarly, if more than one die is provided on the patterning apparatus MA, the patterning apparatus alignment marks can be located between the dies.

[0053] The described apparatus can be used in at least one of the following modes. In stepping mode, the support structure MT and substrate stage WT remain substantially stationary while a pattern imparting a radiation beam is projected onto the target portion C in a single exposure (i.e., a single static exposure). The substrate stage WT is then offset in the X and / or Y directions so that different target portions C can be exposed. In stepping mode, the maximum size of the exposure field limits the size of the target portion C imaged in a single static exposure. In scanning mode, the support structure MT and substrate stage WT are scanned synchronously while the pattern imparting a radiation beam is projected onto the target portion C (i.e., a single dynamic exposure). The velocity and direction of the substrate stage WT relative to the support structure MT can be determined by the (reduced) magnification and image inversion characteristics of the projection system PS. In scanning mode, the maximum size of the exposure field limits the width of the target portion in a single dynamic exposure (in the non-scanning direction), while the length of the scanning motion determines the height of the target portion (in the scanning direction). In another mode, the support structure MT is held substantially stationary to maintain the programmable patterning apparatus, and the substrate stage WT is moved or scanned while the pattern imparting a radiation beam is projected onto the target portion C. In this mode, a pulsed radiation source is typically employed, and the programmable patterning apparatus is updated as needed after each movement of the substrate stage WT or between consecutive radiation pulses during scanning. This operating mode can be readily applied to maskless lithography using programmable patterning apparatus such as programmable mirror arrays of the type described above.

[0054] Alternatively, combinations and / or variations of the above usage patterns or completely different usage patterns may be adopted.

[0055] The substrate may be processed before or after exposure in, for example, a track (a tool typically used to apply a resist layer to the substrate and develop the exposed resist) or a measurement or inspection tool. Where applicable, the disclosure herein may be applied to such substrate processing tools and other substrate processing tools. Furthermore, the substrate may be processed more than once, for example to create a multilayer IC, such that the term "substrate" as used herein may also refer to a substrate that includes multiple processed layers.

[0056] The terms “radiation” and “beam” used in this article for lithography cover all types of electromagnetic radiation, including ultraviolet (UV) or deep ultraviolet (DUV) radiation (e.g., with wavelengths of 365 nm, 248 nm, 193 nm, 157 nm, or 126 nm) and extreme ultraviolet (EUV) radiation (e.g., with wavelengths in the range of 5 nm to 20 nm), as well as particle beams, such as ion beams or electron beams.

[0057] Various patterns on or provided by a patterning apparatus can have different process windows; that is, the processing variable space in which the pattern will be generated within the specification. Examples of pattern specifications related to potential system defects include checks for necking, line pullback, line narrowing, CD, edge placement, overlap, resist top loss, resist undercut, and / or bridging. The process window of a pattern or its region on the patterning apparatus can be obtained by merging (e.g., overlapping) the process windows of each individual pattern. The boundaries of the process windows of a pattern group include the boundaries of the process windows of some of the individual patterns within the individual patterns. In other words, these individual patterns limit the process windows of the pattern group.

[0058] like Figure 2 As shown, the lithography apparatus LA can form part of the lithography unit LC, sometimes also referred to as a lithocell or cluster. The lithography unit LC also includes devices for performing pre- and post-exposure processes on the substrate. Typically, these include one or more spin coaters SC for depositing one or more resist layers, one or more developers for developing the exposed resist, one or more chillers CH, and / or one or more baking plates BK. A substrate processor or robot RO picks up one or more substrates from input / output ports I / O1, I / O2, moves the substrates between different process units, and delivers the substrates to the feed stage LB of the lithography apparatus. These devices, generally referred to as tracks, are controlled by a track control unit TCU, which in turn is controlled by a supervisory control system SCS, which in turn controls the lithography apparatus via the lithography control unit LACU. Therefore, different devices can be operated to maximize throughput and processing efficiency.

[0059] To ensure that the substrate exposed by the photolithography apparatus is correctly and consistently exposed, and / or to monitor portions of a patterning process (e.g., an equipment manufacturing process) including at least one pattern transfer step (e.g., an optical lithography step), it is desirable to inspect the substrate or other object to measure or determine one or more properties, such as alignment, overlay (which may be, for example, between structures in an overlay layer or between structures in the same layer that have been separately provided to layers by, for example, a dual patterning process), line thickness, critical dimension (CD), defocus bias, material properties, etc. Accordingly, manufacturing facilities located in a photolithography bath (LC) typically also include a metrology system that measures some or all of the substrates W (W) that have been processed in the photolithography bath. Figure 1 ) or other objects in the lithography pool. The measurement system can be part of the lithography pool LC, for example, it can be part of the lithography apparatus LA (such as the alignment sensor AS). Figure 1 )).

[0060] The measured parameters may include, for example: alignment; overlay between successive layers formed in or on a patterned substrate; critical dimensions (CD) (e.g., critical linewidth) of features formed on or in a patterned substrate; focus or focus error of an optical lithography step; dose or dose error of an optical lithography step; optical aberrations of an optical lithography step; etc. The measurement is typically performed on one or more dedicated measurement targets provided on the substrate. Measurements may be performed after resist development but before etching, after etching, after deposition, and / or at other times.

[0061] Various techniques exist for measuring structures formed in patterning processes, including the use of scanning electron microscopy, image-based measurement tools, and / or various specialized tools. A rapid and non-destructive form of specialized measurement tool involves directing a radiation beam onto a target on the surface of a substrate and measuring the properties of the scattered (diffracted / reflected) beam. By evaluating one or more properties of the radiation scattered by the substrate, one or more properties of the substrate can be determined. Traditionally, this can be referred to as diffraction-based measurement. Applications of this diffraction-based measurement include measurements of overlay, alignment, etc. For example, overlay and / or alignment can be measured by comparing portions of a diffraction spectrum (e.g., comparing different diffraction orders in the diffraction spectrum of the measurement target, such as a periodic grating).

[0062] Therefore, in device manufacturing processes (e.g., patterning or photolithography), substrates or other objects can undergo various types of measurements during or after the process. Measurements can determine the presence of defects in a particular substrate, establish adjustments to the process and the apparatus used in the process (e.g., aligning two layers on a substrate or aligning a patterning apparatus to the substrate), measure the performance of the process and apparatus, or be used for other purposes. Examples of measurements include optical imaging (e.g., optical microscopy), non-imaging optical measurements (e.g., diffraction-based measurements, such as the ASML LyieldStar metrology tool, the ASML SMASH metrology system), mechanical measurements (e.g., profilometry using probes, atomic force microscopy (AFM)), and / or non-optical imaging (e.g., scanning electron microscopy (SEM)).

[0063] Measurement results can be provided directly or indirectly to the Supervisory Control System (SCS). If an error is detected, adjustments can be made to the exposure of subsequent substrates (especially if the inspection can be completed quickly and timely enough that one or more other substrates in the batch will still be exposed) and / or to the subsequent exposure of the exposed substrate. Furthermore, exposed substrates can be stripped and redone to improve yield, or discarded, thereby avoiding further processing of substrates known to be defective. In cases where only some target portions of the substrate are faulty, additional exposures can be performed only on those target portions that meet specifications. Other manufacturing process adjustments have also been considered.

[0064] Measurement systems can be used to determine one or more properties of a substrate structure, and in particular how one or more properties vary between different substrate structures, or how different layers of the same substrate structure vary layer by layer. Measurement systems can be integrated into a photolithography apparatus (LA) or a photolithography cell (LC), or they can be stand-alone devices.

[0065] To achieve measurement, one or more measurement targets (or measurement markers) are typically provided specifically on a substrate. Typically, the targets are specially designed and may include periodic structures. For example, measurement targets on a substrate (such as a semiconductor wafer) may include one or more 1-D periodic structures (e.g., geometric features, such as gratings), which are printed such that, after development, the periodic structure features are formed by solid resist lines. As another example, measurement targets may include one or more 2-D periodic structures (e.g., gratings), which are printed such that, after development, one or more periodic structures are formed by solid resist pillars or vias in the resist. The gratings, pillars, or vias may optionally be etched into the substrate (e.g., etched into one or more layers on the substrate).

[0066] Figure 3 An example measurement system 10 is depicted, which can be used for overlay detection, alignment, and / or performing other measurement operations. It includes a radiation source 2 that projects or otherwise radiates radiation onto a substrate W, such as a semiconductor wafer (e.g., which may typically include a measurement target). The redirected radiation is delivered to sensors, such as a spectrometer detector 4 and / or other sensors, which measure, for example,... Figure 4 The figure on the left shows the spectrum of specular reflection and / or diffraction radiation (intensity as a function of wavelength). The detector can generate a measurement detection signal, which conveys measurement data indicating the nature of the reflected radiation. Based on this data, the structure or profile of the detected spectrum can be reconstructed by one or more processors (PROs). A general example of a processor (PRO) is shown in [reference needed]. Figure 3 It is shown in the middle.

[0067] As in Figure 1 In a photolithography apparatus LA, one or more substrate stages ( Figure 3 or Figure 4 (Not shown) may be provided to hold the substrate W during measurement operations. One or more substrate stages may be provided in form with Figure 1 The substrate stages WT (WTa or WTb or both) are similar or identical. In the example where the measurement system 10 is integrated with the lithography apparatus, they can be the same substrate stage. Coarse and fine positioners can be provided and configured to accurately position the substrate relative to the measurement optics. Various sensors and actuators are provided, for example, to obtain the position of the target portion of the structure (e.g., a measurement mark) and bring it to a position below the objective lens. Typically, many measurements will be performed on the target portion of the structure at different locations across the substrate W. The substrate support can move in the X and Y directions to obtain different targets and in the Z direction to obtain the desired position of the target portion relative to the focal point of the optics. For ease of thinking and description of the operation, it is as if the objective lens is brought to different positions relative to the substrate when, for example, in practice, the optics can remain substantially stationary (typically in the X and Y directions, but perhaps also in the Z direction) and the substrate moves. As long as the relative positions of the substrate and the optical system are correct, it doesn't matter in principle which one is moving, or whether both are moving, or whether a part of the optical system is moving (e.g., in the Z and / or tilt directions) while the rest of the optical system remains stationary and the substrate is moving (e.g., in the X and Y directions, but optionally in the Z and / or tilt directions).

[0068] For typical metrological measurements, the measurement target 30 on the substrate W can be a 1-D grating, which is printed such that, after development, the grating strips are formed from solid resist lines (e.g., which may be covered by a deposition layer) and / or other materials. Alternatively, the target 30 can be a 2-D grating, which is printed such that, after development, the grating is formed from solid resist pillars and / or other features in the resist.

[0069] Gates, pillars, vias, and / or other features may be etched into or on the substrate (e.g., etched into one or more layers on the substrate), deposited on the substrate, covered by a deposition layer, and / or have other properties. Target 30 (e.g., gates, pillars, vias, etc.) is sensitive to processing variations in the patterning process (e.g., optical aberrations, focus variations, dose variations, etc. in the photolithography projection apparatus, such as those in the projection system), causing these process variations to be reflected in variations of target 30. Therefore, measurement data from target 30 can be used to determine adjustments for one or more manufacturing processes, and / or used as the basis for making actual adjustments.

[0070] For example, measurement data from target 30 can indicate overlay for layers of a semiconductor device. The measurement data from target 30 can be used (e.g., by one or more processors PRO and / or other processors) to determine one or more semiconductor device manufacturing process parameters based on the overlay, and to determine adjustments for a semiconductor device manufacturing apparatus based on the determined one or more semiconductor device manufacturing process parameters. In some embodiments, this may include, for example, stage position adjustment, or it may include determining adjustments for mask design, measurement target design, semiconductor device design, radiation intensity, radiation incident angle, radiation wavelength, pupil size and / or shape, resist material, and / or other process parameters.

[0071] Figure 5 The illustration shows a plan view of a typical measurement target 30 (e.g., a measurement marker), and Figure 4 The typical range of the radiation spot S in the system. Typically, to obtain a diffraction spectrum unaffected by surrounding structures, in one embodiment, the target 30 is a periodic structure (e.g., a grating) larger than the width (e.g., diameter) of the radiation spot S. The width of the spot S can be smaller than the width and length of the target. In other words, the target is "underfilled" by illumination, and the diffraction signal is substantially unaffected by any signals from product features or other external sources. The illumination arrangement can be configured, for example, to provide uniform intensity of illumination across the back focal plane of the objective lens. Alternatively, illumination can be restricted in an on-axis or off-axis direction by, for example, including an aperture in the illumination path.

[0072] Figure 6 The diagram illustrates a measurement system 600, which includes one or more metasurfaces 650 configured to correct aberrations in an incident radiation beam. Note that system 600 is merely a representative example of several different possible types of systems that can utilize metasurface(s) 650 (which may or may not have some or all of the same components and / or may operate in slightly different ways). Examples of such systems include ASML's YieldStar system and / or other systems. System 600 is related to the above-mentioned... Figure 3 The system described is the same as or similar to system 10, wherein one or more components of system 600 are similar to and / or the same as one or more components of system 10 (and Figure 6 Several possible additional components of the system are illustrated. In some embodiments, one or more components of system 600 may replace one or more components of system 10, be used in conjunction with one or more components of system 10, and / or otherwise enhance one or more components of system 10. System 600 includes a radiation source 612 (e.g., with...). Figure 3Source 2 shown is similar to and / or identical to the source 2 shown), and one or more detectors 604 and / or 610 (e.g., with the source 2 shown). Figure 3 The detector shown is similar to and / or the same as 4), and one or more processors PRO (with Figure 3 The processors PRO shown are similar to and / or identical to those shown, as well as various lenses, beam splitters, mirrors, refractive or diffractive elements and / or other components including optical element 675 (see, for example, various reference boxes in system 600). One or more processors PRO are operatively connected to detector 604, detector 610 and / or other components of system 600.

[0073] Figure 6 The illustration shows an illumination branch 625 of system 600, which includes: a radiation source 612; an overlay detection branch 660, which includes a detector 604 and one or more processors PRO; a focusing branch 655; an alignment branch 680, which has a detector 610 (which may be the same as or similar to detector 604) and one or more processors PRO (which may be the processor in overlay detection branch 660, and / or similar to and / or the processor in overlay detection branch 660); an objective lens 690; and / or other components. In some embodiments, the components of system 600 are formed as portions of overlay and / or alignment sensors configured for use in semiconductor manufacturing processes.

[0074] Figure 6 The diagram also illustrates a measurement target 30, which may include one or more measurement markers, such as a diffraction grating target formed, for example, in a substrate 602 (such as a semiconductor wafer), and the one or more measurement markers are collectively referred to as measurement target 30. Target 30 may include one or more structures in a patterned substrate capable of providing diffraction signals. One or more targets 30 may be included in a layer of a substrate, for example, in a semiconductor device structure. In some embodiments, target 30 includes geometric features, such as 1-D or 2-D features, and / or other geometric features. By way of several non-limiting examples, features may include gratings, lines, edges, series of lines and / or edges with fine pitches, and / or other features.

[0075] Various lenses (example objective lens 690 in) Figure 6The various lenses, reflectors, mirrors, refractive or diffractive optical components, and other optical elements 675 are configured to receive, transmit, reflect, focus, and / or perform other operations on irradiation generated by the irradiation source 612, focused by the focusing branch 655, received by the overlay detection branch 660, received by the alignment branch 680, and / or used by other parts of the system 600. These various lenses, reflectors, and / or other optical components may include optical elements. Optical elements are configured to guide, shape, focus, or otherwise control the projected beam of radiation, either jointly or individually. They may include any type of lens, reflector, and / or other optical components configured to allow the system 600 to operate as described herein. For example, objective lens 690 may include one or more lenses formed of any transparent material and have a curved surface configured to focus or otherwise concentrate one or more radiation spots onto target(s)30. The various lenses, reflectors, optical elements, beam splitters, and other optical elements may be positioned in any location and / or at any angle relative to each other that allows the system 600 to operate as described herein. This can include positioning at specific relative distances between elements, at specific angles between elements, etc. In some embodiments, various lenses, reflectors, optical elements, beam splitters, and other optical components are positioned relative to each other in system 600 via structural members, clamps, holders, screws, nuts, bolts, adhesives, and / or other mechanical means. In some embodiments, various elements among the various lenses, reflectors, optical elements, beam splitters, and other optical elements are movable relative to each other. Mobility can be configured to, for example, adjust the position of corresponding illumination spots on one or more targets 30. In some embodiments, mobility includes tilting, translating, or otherwise changing the distances between various lenses, reflectors, and other optical components. Other examples of mobility are also considered.

[0076] In some embodiments, movement can be electronically controlled by a processor (such as processor PRO). Processor PRO can be included in a computing system CS ( Figure 11 It can be operated based on computer or machine-readable instructions (e.g., as described below). Figure 11 Electronic communication can occur by transmitting electronic signals between individual components, transmitting data between individual components of system 600, transmitting values ​​between individual components, and / or other communications. Components of system 600 can communicate via wires or wirelessly via networks (such as the Internet or a combination of the Internet and various other networks, such as local area networks, cellular networks, personal area networks, organizational intranets, and / or other networks).

[0077] In some embodiments, one or more actuators (in) Figure 6An actuator (not shown) may be coupled to one or more components of system 600 and configured to move one or more components of system 600. An actuator may be coupled to one or more components of system 600 via adhesives, clamps, grippers, screws, collars, and / or other mechanisms. The actuator may be configured to be electronically controlled. An individual actuator may be configured to convert an electrical signal into mechanical displacement. The mechanical displacement is configured to move a component of system 600. As an example, one or more actuators in the actuators may be piezoelectric. One or more processors PRO may be configured to control the actuators. One or more processors PRO may be configured to individually control each of the one or more actuators.

[0078] Figure 6 The number of various lenses, reflectors, and / or other optical elements 675 shown is not intended to be limiting. The principles described herein can be extended such that, in some embodiments, system 600 includes additional or fewer lenses, reflectors, and / or other optical elements.

[0079] Radiation source 612 is configured to generate radiation. The generated radiation may be in the form of an incident radiation beam (note that the incident radiation beam described herein may simply be, for example, any radiation beam incident on some optical element 675). The radiation may include illumination, such as light and / or other radiation. In some embodiments, the radiation from radiation source 612 includes a Gaussian radiation beam and / or other radiation. The radiation may have a target wavelength and / or wavelength range, a target intensity, and / or other characteristics. The target wavelength and / or wavelength range, target intensity, etc., may be input and / or selected by the user, determined by system 600 based on previous measurements, and / or otherwise determined. In some embodiments, light includes visible light, infrared light, near-infrared light, and / or other light. In some embodiments, the radiation may be any radiation suitable for interferometric measurements.

[0080] In operation, system 600 is configured such that optical element 675 (or one or more optical elements 675) is configured to receive and transmit the incident radiation beam. Figure 6 In this description, optical element 675 can be any box labeled as optical element 675. As described above, optical element 675 includes lenses, beam splitters, mirrors, refractive or diffractive optical components and / or other optical elements. Optical element 675 introduces aberrations in the incident radiation beam. Aberrations include undesired changes in the target characteristics of the incident radiation beam. Target characteristics can be angle, amplitude, phase / wavefront, polarization, focal position, focal spot quality / uniformity, and / or other characteristics.

[0081] As two examples, aberrations introduce errors into measurement detection signals, leading to alignment and / or overlay measurement deviations. In some embodiments, aberrations include chromatic aberration, spherical aberration, coma, and / or other aberrations. For example, an aberration can be lateral chromatic aberration. Chromatic aberration causes different colors to be focused at different spots. If all colors are focused on the same longitudinal axis (parallel to the optical axis of the lens system), the aberration is called axial chromatic aberration. On the other hand, if different colors are focused along the same focal plane, but they are laterally offset from each other, the aberration is called lateral chromatic aberration. For example, lateral chromatic aberration may occur due to odd aberrations of the lens or due to off-axis illumination.

[0082] One or more metasurfaces 650 are configured to reverse changes in the target characteristics of the incident radiation beam to correct for aberrations caused by optical element 675. The corrected radiation can be used in the illumination branch 625 of the measurement system 600 to illuminate the measurement target 30 on the patterned substrate 602, the corrected radiation can be used by the detector 604 in the overlay detection branch 660 of the measurement system 600 to generate a detection signal (e.g., a measurement signal), the corrected radiation can be used by the detector 610 in the alignment branch 680 of the measurement system 600 to generate a detection signal (e.g., a measurement signal), and / or the corrected radiation can be used for other purposes.

[0083] Compared to the optical design architecture used in existing measurement systems, one or more metasurfaces 650 comprise a novel optical design architecture. As described above, the bulky, multi-element assemblies, typically including mechanical stages, used in existing measurement systems to correct chromatic aberration in radiation are eliminated. Instead, aberration correction is achieved by engineering the optical response of one or more metasurfaces 650 (e.g., controlling the effective refractive index, unit cell geometry, phase, amplitude, and polarization). The one or more metasurfaces may be reflective (or partially reflective), transmissive (or partially transmissive), and / or have other properties. In some embodiments, one or more metasurfaces 650 are positioned before or after a specific optical element 675 (or component) along the optical path of the incident radiation beam. The specific optical element 675 may be known to cause aberrations. For example, in Figure 6 In this configuration, one or more metasurfaces 650 are positioned immediately before objective lens 690 and immediately after another optical element 675 along the optical path of the incident radiation beam traveling from source 612 to measurement target 30. However, this arrangement is not intended to be limiting. One or more metasurfaces 650 may be placed in any location that allows measurement system 600 to operate as described herein.

[0084] In some embodiments, one or more metasurfaces 650 may include, for example: Figure 6The enlarged portion of the diagram shows a single metasurface 651. In some embodiments, one or more metasurfaces 650 may comprise an array of metasurfaces 653, each metasurface 653 configured to modify the amplitude, phase, polarization, and / or other properties of an incident radiation beam. The array may be two-dimensional (2D) and / or have other dimensions. It may also comprise one or more layers of metasurfaces. Other configurations that allow system 600 to operate as described herein are also contemplated.

[0085] Each of the one or more metasurfaces 650 (e.g., each metasurface 651 and / or 653) includes: a body; a beam modifier, such as a nanoantenna, metaatoms, nanoparticles; and / or other structures. The one or more metasurfaces 650 may include electro-optic materials, liquid crystals, phase change materials (e.g., dielectric-to-metal or metal-to-dielectric), and / or other materials. As described herein, the one or more metasurfaces 650 are configured to replace one or more refractive elements, diffractive elements, and / or a moving stage previously used for aberration correction in a metrology system.

[0086] One or more metasurfaces 650 may include different individual metasurfaces, and / or a single metasurface 650 may include different portions configured for different wavelengths, polarizations, diffraction orders, incident angles, phases, and / or other characteristics of the incident radiation. In some embodiments, different metasurfaces and / or portions of a single metasurface may overlap on a metasurface body, and / or may be otherwise mixed on the body. In some embodiments, different metasurfaces 650 and / or different portions of a single metasurface 650 are included in a single body, which may be collectively referred to as metasurfaces. In some embodiments, different metasurfaces 650 and / or different portions of a single metasurface 650 include multiple metasurfaces in a single body, or only individually separated metasurfaces within a body.

[0087] One or more metasurfaces 650 may be active or passive. Active metasurfaces may be reconfigurable metasurfaces. This can be achieved by modifying the structure (moving parts, stretching, etc.) and / or by changing material parameters (applying voltage to change the refractive index in electro-optic materials, changing the orientation in liquid crystals, changing the phase in phase change materials (dielectric to metal or metal to dielectric), etc.) and / or by other methods. Passive metasurfaces may be stationary and / or have no moving parts, and / or may include any metasurface with time-invariant properties (i.e., mechanical or optical properties are fixed).

[0088] Figure 7 The illustration shows an example metasurface 700. Metasurface 700 is... Figure 6 Possible examples of one or more metasurfaces 650 are shown. Figure 7 A schematic diagram 702 includes a portion of the metasurface 700, and magnified and expanded scanning electron microscope views 704 and 706 of the metasurface 700. Schematic diagram 702 includes a perspective view 703, a top view 705, and a side view 707. The metasurface 700 includes: a body 710; a beam modifier 712, such as a nanoantenna, metaatoms, nanoparticles; and / or other structures. The metasurface 700 may include electro-optic materials, liquid crystals, phase change materials (e.g., dielectric-to-metal or metal-to-dielectric), and / or other materials. In this example, the metasurface 700 is reflective. The metasurface 700 includes silicon (Si) beam modifiers and / or any high refractive index material (e.g., SiN, TiO2, lithium niobate, AlN, etc.), and the body 710 includes a silicon dioxide (SiO2) substrate. Each beam modifier 712 may have a square or rectangular cross-section, and / or any other cross-sectional shape that facilitates achieving the performance described herein. The beam modifier 712 can be arranged in parallel and vertical rows, in a cellular lattice, in other types of lattices, and / or in any other layout that facilitates the achievement of the performance described herein. These shapes and / or this configuration are merely examples and can be varied depending on the application. The metasurface 700 may include different portions (e.g., certain subsets of rows and columns in this example) configured for different wavelengths, polarizations, diffraction orders, incident angles, phases, polarizations, and / or other characteristics of the incident radiation; and / or other layouts.

[0089] By engineering the geometry and / or arrangement of the beam modifier 712, reflected (as in this example), deflected, and / or transmitted radiation can be controlled. For example, the metasurface 700 can be used to locally control the sign of the dispersion of the incident radiation beam (e.g., causing the beam to be dispersed or focused, for example). This allows system 600 ( Figure 6This reduces or increases the lateral offset of the incident radiation beam (caused by aberrations) at different wavelengths. In conjunction with controlling the offset, the angle of the deflected radiation can also be controlled using a metasurface similar to metasurface 700. More information on engineering the geometry of beam modifier 712 and / or controlling the offset and / or angle of reflected, deflected, and / or transmitted radiation can be found in articles such as, for example, Ehsan Arbabi, Amir Arbabi, Seyedeh Mahsa Kamali, Yu Horie, and Andrei Faraon, "Controlling the sign of chromatic dispersion in diffractive optics with dielectric metasurfaces," Optica 4, 625-632 (2017); and / or McClung, A., Mansouree, M. & Arbabi, A. “At-will chromatic dispersion by prescribing lighttrajectories with cascaded metasurfaces.” Light Sci Appl 9, 93 (2020).

[0090] Return to Figure 6 In some embodiments, undesirable changes to the target characteristics of the incident radiation beam include beam deflection due to changes in wavelength. It also includes distortions in beam quality and uniformity. One or more metasurfaces are configured to guide the incident radiation beam back to the target position, which helps eliminate the mechanical movement required for the stage of the measurement system. In some embodiments, undesirable changes include changes in the trajectory of the incident radiation beam away from the target focus. One or more metasurfaces are configured to redirect the incident radiation beam back to the target focus.

[0091] Figure 8 and Figure 9 The illustration shows optical element 800 (e.g., Figure 6 The optical element 675 shown above is a representative example) and the metasurface 804 (e.g., Figure 6 As shown in the example of one or more metasurfaces 650 described above, optical element 800 is configured to receive and transmit incident radiation beam 802, and metasurface 804 is configured to reverse changes in the target characteristics of beam 802 to correct for aberrations caused by optical element 800. In this example, the aberration is lateral chromatic aberration 808, and optical element 800 is the illumination branch of the measurement system (e.g., Figure 6The system 600 shown is a portion of the irradiation branch 625. However, similar examples have been considered for the detection branch of the measurement system and / or other locations within the measurement system.

[0092] Specifically, Figure 8 The illustration shows a side view of the incident radiation beam 802, the optical element 800 (a lens in this example), and the lateral chromatic aberration 808. Figure 9 The illustration shows a side view of the same incident radiation beam 802 and optical element 800, but with multiple metasurfaces 804 configured to correct lateral chromatic aberration 808. Figure 8 and Figure 9 Both also illustrate the aperture stop 810 and image plane 812 associated with the incident radiation beam 802 and the optical element 800. In this example, a substrate such as a semiconductor wafer may be positioned in the image plane 812. The optical element 800 causes lateral chromatic aberration 808 in the incident radiation beam 802. Lateral chromatic aberration 808 includes undesired changes to the target characteristics of the incident radiation beam 802. In this example, undesired changes to the target characteristics of the incident radiation beam include a shift in the center of the spot on the image plane 812 for different wavelengths within the incident radiation beam 802 (see the bidirectional arrows indicating the portion for lateral chromatic aberration 808). In this example, the dark and light arrows constituting the incident radiation beam 802 may produce color shifts (from dark to light or from light to dark), depending on the shift caused by the optical element 800. In some embodiments, undesired changes include a change in the trajectory of the incident radiation beam 802 away from the target focus. Figure 9 As shown, multiple metasurfaces 804 are configured to guide the incident radiation beam 802 back to the target position or focus 820 on the image plane 812 (in this example). This can reverse any color shift between the dark and light arrows. In some embodiments, depending on the application, the metasurfaces may be located in front of the optical system 800.

[0093] Generally, aberrations can be classified into monochromatic aberration and chromatic aberration. The former depends on the geometry of the optical device 800 and the orientation and distribution of the incident beam 802 relative to the optical device 800, while the latter is caused by the dispersive properties of the optical system 800. Metasurfaces can help correct both types of aberrations.

[0094] Return to Figure 6Detectors 604 and / or 610 are configured to generate a detection signal. The detection signal may be generated based on the reflected radiation detected from the diffraction grating target(s)(e.g., measurement target 30). In some embodiments, detectors 604 and / or 610 include an interferometer, a camera, a single-pixel or multi-pixel photodetector, and / or other detectors. In some embodiments, detectors 604 and / or 610 are configured to detect the diffraction order, phase, intensity, wavelength, and / or polarization of the diffraction radiation received from the measurement target 30, and to generate a detection signal based on the diffraction order, phase, intensity, wavelength, and / or polarization.

[0095] For example, detectors 604 and / or 610 may receive first-order or higher-order diffracted radiation from measurement target 30, which diffracts the incident radiation beam before or after the optical element 675 or objective lens 690 induces aberrations and one or more metasurfaces 650 reverse changes in target characteristics to correct for aberrations. Detectors 604 and / or 610 generate a detection signal based on the received diffracted radiation. The detection signal includes measurement information related to the target(s). For example, the detection signal may be and / or be used to determine overlay and / or alignment measurement signals, including overlay and / or alignment measurement information, and / or other measurement signals. Measurement information (e.g., overlay values, alignment values, and / or other information) may be determined using interferometry principles and / or other principles. As described herein, detectors 604 and / or 610 may respectively form portions of the overlay detection sensor and / or alignment sensor represented by system 600 and / or system 10. The alignment sensor and / or overlay detection sensor may be configured for, for example, a semiconductor wafer and may be used in semiconductor manufacturing processes.

[0096] The detection signal includes an electronic signal representing and / or otherwise corresponding to radiation diffracted and / or otherwise reflected from (multiple) targets. The diffracted radiation from the targets may include, for example, +1st-order and -1st-order diffracted radiation. The detection signal may indicate, for example, measurements associated with a diffraction grating target, and / or other information. Generating the detection signal includes sensing the reflected radiation and converting the sensed reflected radiation into an electronic signal. In some embodiments, generating the detection signal includes sensing different portions of reflected radiation from different regions and / or different geometries of the target and / or multiple targets, and combining the different portions of reflected radiation to form the detection signal. This may include generating and / or analyzing one or more images of the target using the radiation described herein.

[0097] Figure 10The figure illustrates a measurement method 1001. In some embodiments, method 1001 is performed as part of, for example, an overlay and / or alignment sensing operation in a semiconductor device manufacturing process. In some embodiments, one or more operations of method 1001 may be implemented in or by a measurement system, and / or implemented in or by another system, such as a measurement system... Figure 6 As shown (and in Figures 7 to 9 (See the diagram below) System 600, such as Figure 3 System 10 shown, computer system (e.g., such as...) Figure 11 As shown and described below). In some embodiments, method 1001 includes generating (operation 1002) an incident radiation beam, receiving and transmitting (operation 1004) the incident radiation beam, reversing (operation 1006) a change in the target characteristics of the incident radiation beam to correct for aberrations caused at operation 1004, generating (operation 1008) a detection signal, and / or other operations.

[0098] The operation of method 1001 is intended to be illustrative. In some embodiments, method 1001 may be performed using one or more additional operations not described and / or without one or more of the operations discussed. For example, in some embodiments, method 1001 may include additional operations including determining overlay and / or alignment for a semiconductor wafer, and determining adjustments for a semiconductor device manufacturing process. Furthermore, Figure 10 The order of operations of the method 1001 shown and described is not intended to be limiting.

[0099] In some embodiments, one or more portions of method 1001 may be implemented in and / or controlled by one or more processing devices (e.g., digital processor, analog processor, digital circuitry designed to process information, analog circuitry designed to process information, state machine, and / or other mechanisms for electronically processing information). The one or more processing devices may include one or more devices that perform some or all of the operations of method 1001 in response to instructions electronically stored on an electronic storage medium. The one or more processing devices may include one or more devices configured by hardware, firmware, and / or software specifically designed to perform one or more operations of method 1001 (e.g., see below regarding...). Figure 11 (Discussion).

[0100] At operation 1002, an incident radiation beam is generated. The incident radiation beam is generated by a radiation source, which is part of the measurement system. In some embodiments, the radiation source and... Figure 3 Source 2 and / or shown Figure 6As shown, the source 612 mentioned above is the same as or similar to it.

[0101] At operation 1004, the optical elements of the measurement system receive and transmit the incident radiation beam. The optical elements include lenses, beam splitters, mirrors, refractive or diffractive optical components, and / or other optical elements. The optical elements introduce aberrations in the incident radiation beam. Aberrations include undesired changes to the target characteristics of the incident radiation beam. In some embodiments, aberrations include chromatic aberration, spherical aberration, coma, and / or other aberrations. For example, an aberration may be lateral chromatic aberration. The optical elements may be... Figure 6 As shown, one or more optical elements of the measurement system 600 described above are similar and / or identical.

[0102] At operation 1006, the change in the target characteristics of the incident radiation beam is reversed to correct for aberrations caused by the optical elements. For example, the corrected radiation can be used in the illumination branch of the measurement system to illuminate the measurement target on the patterned substrate, and / or used by the detector in the detection branch of the measurement system to generate a detection signal (e.g., a measurement signal).

[0103] One or more metasurfaces are used for this inversion and aberration correction. One or more metasurfaces can be used with... Figure 6 (as well as Figures 7 to 9 The metasurfaces 650 described above are similar to and / or identical to those shown in the diagram. As described above, in some embodiments, the one or more metasurfaces are configured to modify the amplitude, phase, polarization, and / or other characteristics of the incident radiation beam. In some embodiments, the one or more metasurfaces are positioned ahead of the optical element along the optical path of the incident radiation beam. In some embodiments, the one or more metasurfaces are positioned behind the optical element along the optical path of the incident radiation beam.

[0104] In some embodiments, one or more metasurfaces comprise an array of metasurfaces. The array may be two-dimensional (2D) and / or have other dimensions. Each metasurface includes a nanoantenna, metaatom, nanoparticle, and / or other structure. The one or more metasurfaces may be active or passive. In some embodiments, one or more metasurfaces are configured to replace one or more refractive elements, diffractive elements, and / or a moving stage previously used for aberration correction in a metrology system.

[0105] For example, in some embodiments, undesirable changes to the target characteristics of the incident radiation beam include deflection of the incident radiation beam due to changes in wavelength. One or more metasurfaces are configured to adjust the incident radiation beam back to the target position, which helps eliminate the mechanical movement required for the stage of the measurement system. In some embodiments, undesirable changes include changes in the trajectory of the incident radiation beam away from the target focus. One or more metasurfaces are configured to redirect the incident radiation beam back to the target focus.

[0106] At operation 1008, a detection signal can be generated. The detection signal can be generated based on the reflected radiation detected from the diffraction grating target(s), as described above. For example, operation 1008 may include receiving first-order or higher-order diffracted radiation from the measurement target, and generating a detection signal before or after the measurement target diffracts the incident radiation beam before or after optical elements induce aberrations and one or more metasurfaces reverse changes in target properties to correct for the aberrations. The detection signal is generated by a detector (such as...) Figure 3 Detectors 4 in the middle, such as Figure 6 The detector (such as detectors 604 and / or 610, and / or other detectors) is generated based on the radiation received by the detector. The detection signal includes measurement information related to the target(s). For example, the detection signal may be and / or be used to determine overlay and / or alignment measurement signals, and / or other measurement signals, including overlay and / or alignment measurement information. The measurement information (e.g., overlay values, alignment values, and / or other information) may be determined using interferometry principles and / or other principles.

[0107] In some embodiments, method 1001 includes detecting reflected radiation from one or more diffraction grating targets. Detecting reflected radiation includes detecting one or more phase and / or amplitude (intensity) shifts in reflected radiation from one or more geometric features of the targets(s). The one or more phase and / or amplitude shifts correspond to one or more dimensions of the target. For example, the phase and / or amplitude of reflected radiation from one side of the target may differ from the phase and / or amplitude of reflected radiation from the other side of the target.

[0108] Detecting one or more phase and / or amplitude (intensity) shifts in reflected radiation from a target involves measuring local phase shifts (e.g., local phase differences) and / or amplitude variations corresponding to different portions of the target. For example, reflected radiation from a specific region of the target may include a sinusoidal waveform with a specific phase and / or amplitude. Reflected radiation from different regions of the target (or targets in different layers) may also include sinusoidal waveforms, but with different phases and / or amplitudes. The detected reflected radiation also includes measuring phase and / or amplitude differences in reflected radiation at different diffraction orders. Detection of one or more local phase and / or amplitude shifts can be performed, for example, using Hilbert transforms and / or other techniques. Interferometry techniques and / or other operations can be used to measure phase and / or amplitude differences in reflected radiation at different diffraction orders.

[0109] In some embodiments, method 1001 includes determining adjustments for a semiconductor device manufacturing process. In some embodiments, method 1001 includes determining one or more semiconductor device manufacturing process parameters. The one or more semiconductor device manufacturing process parameters may be determined based on one or more detected phase and / or amplitude changes, overlay and / or alignment values ​​indicated by detected signals, and / or other similar systems and / or other information. The one or more parameters may include parameters of radiation (radiation used for measurement), overlay values, alignment values, measurement inspection locations on layers of the semiconductor device structure, radiation beam trajectories across targets, and / or other parameters. In some embodiments, process parameters may be broadly interpreted to include stage position, mask design, measurement target design, semiconductor device design, radiation intensity (for exposing resist, etc.), radiation incident angle (for exposing resist, etc.), radiation wavelength (for exposing resist, etc.), pupil size and / or shape, resist material, and / or other parameters.

[0110] In some embodiments, method 1001 includes determining process adjustments based on one or more determined semiconductor device manufacturing process parameters, adjusting semiconductor device manufacturing apparatus, and / or other operations based on the determined adjustments. For example, if a determined measurement is outside the process tolerance, the out-of-tolerance measurement may be caused by one or more manufacturing processes in which process parameters have drifted and / or otherwise changed, causing the process to no longer produce acceptable device (e.g., the measurement may exceed an acceptable threshold). One or more new or adjusted process parameters may be determined based on the measurement. The new or adjusted process parameters may be configured to cause the manufacturing process to produce acceptable device again.

[0111] For example, new or adjusted process parameters can bring previously unacceptable measurements back into acceptable ranges. The new or adjusted process parameters can be compared with existing parameters for a given process. If a difference exists, that difference can be used to determine adjustments for the apparatus used in the manufacturing equipment (e.g., parameter "x" should be increased / decreased / changed to match a new or adjusted version of parameter "x" determined as part of method 1001). In some embodiments, method 1001 may include electronically adjusting the apparatus (e.g., based on the determined process parameters). Electronically adjusting the apparatus may include sending electronic signals and / or other communications to the apparatus, such as causing changes within the apparatus. Electronic adjustment may include, for example, changing settings and / or other adjustments on the equipment.

[0112] Figure 11 This is a diagram of an example computer system CS that can be used for one or more of the operations described herein. The computer system CS includes a bus BS or other communication mechanism for transmitting information, and a processor PRO (or related to...). Figure 3 The processor PRO shown may be similar to or the same as multiple processors. The processor PRO is coupled to the bus BS for processing information. The computer system CS also includes main memory MM, such as random access memory (RAM) or other dynamic storage devices, coupled to the bus BS for storing information and instructions to be executed by the processor PRO. The main memory MM may also be used to store temporary variables or other intermediate information during instruction execution by the processor PRO. The computer system CS also includes read-only memory (ROM) or static storage devices coupled to the bus BS for storing static information and instructions for the processor PRO. Storage devices SD, such as disks or optical discs, are provided and coupled to the bus BS for storing information and instructions.

[0113] The computer system CS can be coupled to a display DS, such as a flat panel or touchscreen display or a cathode ray tube (CRT), via a bus BS to display information to the computer user. Input devices ID, including alphanumeric and other keys, are coupled to the bus BS to transmit information and command selections to the processor PRO. Another type of user input device is a cursor controller CC, such as a mouse, trackball, or arrow keys, used to transmit directional information and command selections to the processor PRO and to control cursor movement on the display DS. This input device typically has two degrees of freedom on two axes (e.g., a first axis (x) and a second axis (e.g., y)), allowing the device to specify its position in a plane. Touch panel (screen) displays can also be used as input devices.

[0114] In some embodiments, all or part of the operations described herein may be executed by a computer system CS in response to a processor PRO executing one or more sequences of one or more instructions contained in main memory MM. Such instructions may be read into main memory MM from another computer-readable medium, such as a storage device SD. Execution of the sequence of instructions included in main memory MM causes processor PRO to perform the process steps (operations) described herein. One or more processors in a multiprocessor arrangement may also be employed to execute the sequence of instructions contained in main memory MM. In some embodiments, hardwired circuitry may be used in place of or in combination with software instructions. Therefore, the description herein is not limited to any particular combination of hardware circuitry and software.

[0115] The term "computer-readable medium" or "machine-readable medium" refers to any medium that participates in providing instructions to be executed to the processor PRO. Such media can take many forms, including but not limited to non-volatile media, volatile media, and transmission media. Non-volatile media include, for example, optical discs or magnetic disks, such as storage devices SD. Volatile media include dynamic memory, such as main memory MM. Transmission media include coaxial cables, copper wires, and optical fibers, including conductors containing a bus BS. Transmission media can also take the form of sound waves or light waves, such as sound waves or light waves generated during radio frequency (RF) and infrared (IR) data communications. Computer-readable media can be non-transitory, such as floppy disks, flexible disks, hard disks, magnetic tapes, any other magnetic media, CD-ROMs, DVDs, any other optical media, punched cards, paper tapes, any other physical media with a perforated pattern, RAM, PROMs, EPROMs, FLASH-EPROMs, any other memory chips, or cassette tapes. Non-transitory computer-readable media can have instructions recorded on it. When executed by a computer, the instructions can perform any of the operations described herein. Transient computer-readable media may include, for example, carrier waves or other propagating electromagnetic signals.

[0116] Various forms of computer-readable media can involve transmitting one or more sequences of one or more instructions to a processor PRO for execution. For example, the instructions may initially be carried on a disk of a remote computer. The remote computer may load the instructions into its dynamic memory and transmit them over a telephone line using a modem. A modem local to the computer system CS can receive data over the telephone line and convert the data into an infrared signal using an infrared transmitter. An infrared detector coupled to a bus BS can receive the data transmitted in the infrared signal and place the data on the bus BS. The bus BS transmits the data to main memory MM, and the processor PRO retrieves and executes the instructions from the main memory MM. The instructions received by the main memory MM may optionally be stored on a storage device SD before or after execution by the processor PRO.

[0117] The computer system CS may also include a communication interface CI coupled to the bus BS. The communication interface CI provides bidirectional data communication to the network link NDL connected to the local area network (LAN). For example, the communication interface CI may be an Integrated Services Digital Network (ISDN) card or a modem to provide data communication connectivity to a corresponding type of telephone line. As another example, the communication interface CI may be a LAN card to provide data communication connectivity to a compatible LAN. Wireless links may also be implemented. In any such implementation, the communication interface CI transmits and receives electrical, electromagnetic, or optical signals that carry streams of digital data representing various types of information.

[0118] A network link (NDL) typically provides data communication to other data devices over one or more networks. For example, a network link (NDL) can provide a connection to a host computer (HC) via a local area network (LAN). This can include data communication services provided via a global packet data communication network (now commonly referred to as the "Internet" INT). A LAN (Internet) can use electrical, electromagnetic, or optical signals to transmit digital data streams. Signals through the various networks, as well as signals on the network data link (NDL) and through the communication interface (CI) (which transmits digital data to and from the computer system (CS)), are exemplary forms of carrier waves for transmitting information.

[0119] The computer system CS can send and receive messages, including program code, via (multiple) networks, network data links (NDL), and communication interfaces (CI). In the Internet example, the host computer HC can transmit the requested application code via the Internet (INT), network data links (NDL), local area networks (LAN), and communication interfaces (CI). An application downloaded in this way can provide all or part of the methods described herein. The received code can be executed by the processor PRO upon receipt and / or stored in storage devices (SD) or other non-volatile memory for later execution. In this way, the computer system CS can obtain application code in carrier form.

[0120] Various embodiments of this system and method are disclosed in a subsequent list of numbered clauses. Further features, characteristics, and exemplary technical solutions of this disclosure will be described below with clauses that may optionally be claimed in any combination: 1. A measurement system associated with semiconductor manufacturing, the system comprising: an optical element configured to receive and transmit an incident radiation beam, the optical element inducing aberrations in the incident radiation beam, the aberrations including undesired changes to a target characteristic of the incident radiation beam; and one or more metasurfaces configured to reverse the changes to the target characteristic to correct the aberrations induced by the optical element. 2. The system according to Clause 1, wherein the one or more metasurfaces comprise an array of metasurfaces. 3. The system according to any one of the preceding clauses, wherein the array of said metasurfaces comprises a two-dimensional (2D) array of metasurfaces. 4. The system according to any one of the preceding clauses, wherein each metasurface comprises a nanoantenna, metaatoms, or nanoparticles. 5. The system according to any one of the preceding clauses, wherein the one or more metasurfaces are active. 6. The system according to any one of the preceding clauses, wherein the one or more metasurfaces are passive. 7. The system according to any one of the preceding clauses, wherein the calibrated radiation beam is configured to be used in the irradiation branch of the measurement system to irradiate a measurement target on a patterned substrate, and / or used by a detector in the detection branch of the measurement system to generate a measurement detection signal. 8. The system according to any one of the preceding clauses, wherein the aberrations include chromatic aberration, spherical aberration, and / or coma. 9. The system according to any one of the preceding clauses, wherein the aberration includes lateral chromatic aberration. 10. The system according to any one of the preceding clauses, wherein the undesired change in the target characteristic of the incident radiation beam includes a shift of the incident radiation beam due to a change in wavelength, and the one or more metasurfaces are configured to adjust the incident radiation beam back to the target position, which helps to eliminate the mechanical movement required for the stage of the measurement system. 11. The system according to any one of the preceding clauses, wherein the undesired change includes a change in the trajectory of the incident radiation beam away from the target focus; and wherein the one or more metasurfaces are configured to redirect the incident radiation beam back to the target focus. 12. The system according to any one of the preceding clauses, wherein the one or more metasurfaces are positioned in front of the optical element along the optical path of the incident radiation beam. 13. The system according to any one of the preceding clauses, wherein the one or more metasurfaces are positioned after the optical element along the optical path of the incident radiation beam. 14. The system according to any one of the preceding clauses, wherein the optical element comprises a lens, a beam splitter, a mirror, and / or a refractive or diffractive optical component. 15. The system according to any one of the preceding clauses, wherein the one or more metasurfaces are configured to replace one or more refractive elements, diffractive elements and / or a movable stage previously used for aberration correction in the measurement system. 16. The system according to any one of the preceding clauses, wherein the one or more metasurfaces are further configured to modify the amplitude, phase, and / or polarization of the incident radiation beam. 17. The system according to any one of the preceding clauses further includes a radiation source configured to generate the incident radiation beam. 18. The system according to any one of the preceding clauses further includes a detector configured to: receive first-order or higher-order diffracted radiation from a measurement target, the measurement target diffracting the incident radiation beam before or after the optical element causes the aberration and the one or more metasurfaces reverse the change in the target characteristics to correct the aberration; and generate a detection signal. 19. The system according to any one of the preceding clauses, wherein the optical element and one or more metasurfaces form part of the alignment sensor and / or overlay detection sensor. 20. The system of claim 19, wherein the alignment sensor and / or the overlay detection sensor are configured for use on a semiconductor wafer and are used in a semiconductor manufacturing process. 21. A measurement method associated with semiconductor manufacturing, the method comprising: receiving and transmitting an incident radiation beam using an optical element, the optical element causing aberrations in the incident radiation beam, the aberrations including an undesired change in a target characteristic of the incident radiation beam; and reversing the change in the target characteristic using one or more metasurfaces to correct the aberrations caused by the optical element. 22. The method according to Clause 21, wherein the one or more metasurfaces comprise an array of metasurfaces. 23. The method according to any one of the preceding clauses, wherein the array of said metasurfaces comprises a two-dimensional (2D) array of metasurfaces. 24. The method according to any one of the preceding clauses, wherein each metasurface comprises a nanoantenna, metaatoms, or nanoparticles. 25. The method according to any one of the preceding clauses, wherein the one or more metasurfaces are active. 26. The method according to any one of the preceding clauses, wherein the one or more metasurfaces are passive. 27. The method according to any one of the preceding clauses further comprises: using a calibrated radiation beam in the illumination branch of the measurement system to irradiate the measurement target on the patterned substrate, and / or using the calibrated radiation beam by a detector in the detection branch of the measurement system to generate a measurement detection signal. 28. The method according to any one of the preceding clauses, wherein the aberrations include chromatic aberration, spherical aberration, and / or coma. 29. The method according to any one of the preceding clauses, wherein the aberration includes lateral chromatic aberration. 30. The method according to any one of the preceding clauses, wherein the undesired change in the target characteristic of the incident radiation beam includes a shift of the incident radiation beam due to a change in wavelength, and the one or more metasurfaces are configured to adjust the incident radiation beam back to the target position, which helps to eliminate the mechanical movement required for the stage of the measurement system. 31. The method according to any one of the preceding clauses, wherein the undesired change includes a change in the trajectory of the incident radiation beam away from the target focus; and wherein the one or more metasurfaces are configured to redirect the incident radiation beam back to the target focus. 32. The method according to any one of the preceding clauses, wherein the one or more metasurfaces are positioned in front of the optical element along the optical path of the incident radiation beam. 33. The method according to any one of the preceding clauses, wherein the one or more metasurfaces are positioned after the optical element along the optical path of the incident radiation beam. 34. The method according to any one of the preceding clauses, wherein the optical element comprises a lens, a beam splitter, a mirror, and / or a refractive or diffractive optical component. 35. The method according to any one of the preceding clauses, wherein the one or more metasurfaces are configured to replace one or more refractive elements, diffractive elements and / or a movable stage previously used for aberration correction in the measurement system. 36. The method according to any one of the preceding clauses, wherein the one or more metasurfaces are further configured to modify the amplitude, phase, and / or polarization of the incident radiation beam. 37. The method according to any one of the preceding clauses further includes generating the incident radiation beam using a radiation source. 38. The method according to any one of the preceding clauses further includes using a detector to: receive first-order or higher-order diffracted radiation from a measurement target, the measurement target diffracting the incident radiation beam before or after the optical element causes the aberration and the one or more metasurfaces reverse the change in the target characteristics to correct the aberration; and generate a detection signal. 39. The method according to any one of the preceding clauses, wherein the optical element and one or more metasurfaces form part of the alignment sensor and / or overlay detection sensor. 40. The method according to any one of the preceding clauses, wherein the alignment sensor and / or the overlay detection sensor are configured for use on a semiconductor wafer and are used in a semiconductor manufacturing process.

[0121] The concepts disclosed herein can be associated with any general imaging system used for imaging subwavelength features and may be particularly useful for emerging imaging techniques capable of producing increasingly shorter wavelengths. Emerging techniques already in use include EUV (Extreme Ultraviolet) and DUV lithography, which can produce wavelengths of 193 nm using ArF lasers and even 157 nm using fluorine lasers. Furthermore, EUV lithography can produce wavelengths in the 20–5 nm range by using synchrotrons or by utilizing high-energy electrons to bombard materials (solid-state or plasma) to generate photons in this range.

[0122] While the concepts disclosed herein can be used for imaging on substrates such as silicon wafers, it should be understood that the disclosed concepts can be used in any type of lithography imaging system, such as a lithography imaging system for imaging on substrates other than silicon wafers. Furthermore, combinations and sub-combinations of the disclosed elements may include individual embodiments.

[0123] The above description is intended to be illustrative and not restrictive. Therefore, it will be apparent to those skilled in the art that modifications can be made to the description without departing from the scope of the set forth claims.

Claims

1. A measurement system associated with semiconductor manufacturing, the system comprising: An optical element configured to receive and transmit an incident radiation beam, the optical element inducing aberrations in the incident radiation beam, the aberrations including undesired changes to the target characteristics of the incident radiation beam; as well as One or more metasurfaces are configured to reverse the change in the target characteristic to correct the aberration caused by the optical element.

2. The system of claim 1, wherein the one or more metasurfaces comprise an array of metasurfaces.

3. The system of claim 2, wherein the array of metasurfaces comprises a two-dimensional 2D array of metasurfaces.

4. The system according to claim 2 or 3, wherein each metasurface comprises a nanoantenna, metaatoms, or nanoparticles.

5. The system according to any one of claims 2 to 4, wherein the one or more metasurfaces are active.

6. The system according to any one of claims 2 to 4, wherein the one or more metasurfaces are passive.

7. The system according to any one of claims 1 to 6, wherein the calibrated radiation beam is configured to be used in the irradiation branch of the measurement system to irradiate a measurement target on a patterned substrate, and / or used by a detector in the detection branch of the measurement system to generate a measurement detection signal.

8. The system according to any one of claims 1 to 7, wherein the aberrations include chromatic aberration, spherical aberration, and / or coma.

9. The system according to any one of claims 1 to 8, wherein the aberration includes lateral chromatic aberration.

10. The system according to any one of claims 1 to 9, wherein the undesired change in the target characteristic of the incident radiation beam includes a shift of the incident radiation beam due to a change in wavelength, and the one or more metasurfaces are configured to adjust the incident radiation beam back to the target position, which helps to eliminate the mechanical movement required for the stage of the measurement system.

11. The system according to any one of claims 1 to 10, wherein the undesired change includes a change in the trajectory of the incident radiation beam away from the target focus; and wherein the one or more metasurfaces are configured to redirect the incident radiation beam back to the target focus.

12. The system according to any one of claims 1 to 11, wherein the one or more metasurfaces are positioned in front of the optical element along the optical path of the incident radiation beam.

13. The system according to any one of claims 1 to 11, wherein the one or more metasurfaces are positioned after the optical element along the optical path of the incident radiation beam.

14. The system according to any one of claims 1 to 13, wherein the optical element comprises a lens, a beam splitter, a mirror, and / or a refractive or diffractive optical component.

15. The system according to any one of claims 1 to 14, wherein the one or more metasurfaces are configured to replace one or more refractive elements, diffractive elements and / or moving stages previously used for aberration correction in the measurement system.

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