Measurement system and method based on optical vortex

Abstract

Optical vortex-based metrology systems and methods are described. The radiation source is configured to radiate a metrology target in one or more layers of the patterned substrate with radiation. The metrology target is configured to diffract radiation from the radiation source and impart orbital angular momentum to radiation from the radiation source. The radiation sensor is configured to generate a measurement signal based on an orbital angular momentum of diffracted radiation received from a measurement target. The measurement signal comprises alignment position information and / or overlay information of one or more layers. Advantageously, the orbital angular momentum of the diffracted radiation can carry additional information useful for generating more accurate measurements compared to existing metrology systems using only phase or intensity information.

Description

Cross-reference to related applications

[0001] This application claims priority to U.S. Application 63 / 539,035, filed September 18, 2023, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This specification relates to measurement systems and methods based on optical vortices. Background Technology

[0003] Photolithography projection equipment can be used, for example, in the fabrication of integrated circuits (ICs). A patterning apparatus (e.g., a mask) can include or provide a pattern (“design layout”) corresponding to individual layers of the IC, and this pattern can be transferred onto target portions (e.g., comprising one or more dies) on a substrate (e.g., a silicon wafer) coated with a radiation-sensitive material layer (“resist”) by methods such as irradiating the target portions through the pattern on the patterning apparatus. Typically, a single substrate comprises multiple adjacent target portions, and the pattern is sequentially transferred onto these target portions one at a time by the photolithography projection equipment. In one type of photolithography projection equipment, the pattern on the entire patterning apparatus is transferred onto a target portion in a single operation. This type of equipment is commonly referred to as a stepper. In an alternative equipment, commonly referred to as a step-scanning apparatus, a projection beam scans the patterning apparatus in a given reference direction (“scanning” direction) while the substrate moves synchronously parallel or antiparallel to that reference direction. Different portions of the pattern on the patterning apparatus are progressively transferred onto a target portion. Since photolithography projection equipment typically has a reduction ratio M (e.g., 4), the substrate movement speed F will be 1 / M times the speed of the projection beam scanning patterning device.

[0004] Before the pattern is transferred from the patterning device to the 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 series of processes serves as the basis for manufacturing individual layers of devices (e.g., ICs). The substrate may then undergo various processes such as etching, ion implantation (doping), metallization, oxidation, deposition, chemical mechanical polishing, etc., all of which are designed to complete 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, each target portion on the substrate will have a device. These devices are then separated from each other using techniques such as dicing or sawing to mount the individual devices onto a carrier, connect them to pins, etc.

[0005] Therefore, manufacturing devices (e.g., semiconductor devices) typically involves processing a substrate (e.g., a semiconductor wafer) using numerous manufacturing processes to form various features and multiple layers of the device. Such layers and features are typically fabricated and processed using processes such as deposition, photolithography, etching, chemical mechanical polishing, and ion implantation. Multiple devices can be fabricated on multiple dies on a substrate and then separated into individual devices. This device manufacturing process can be considered a patterning process. A patterning process involves patterning steps for transferring a pattern from a patterning device onto a substrate, such as optical and / or nanoimprint lithography using a patterning device in a photolithography apparatus, and typically, but optionally, involves one or more associated patterning processing steps, such as resist development by a developing apparatus, baking the substrate using a baking tool, etching the pattern using an etching apparatus, deposition, etc.

[0006] Photolithography is a core step in the fabrication of 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 to fabricate flat panel displays, microelectromechanical systems (MEMS), and other devices.

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

[0008] According to the resolution formula CD = k1 × λ / NA (where λ is the wavelength of radiation used (currently 248 nm or 193 nm in most cases), NA is the numerical aperture of the projection optics in the lithography projection apparatus, CD is the "critical size," typically the minimum feature size for printing, and k1 is the empirical resolution factor), the process of printing features smaller than the classical resolution limits of the lithography projection apparatus is generally referred to as low-k1 lithography. Typically, the smaller k1 is, the more difficult it is to reproduce patterns on the substrate that are similar in shape and size to those planned by the designer to achieve specific electrical functions and performance. To overcome these difficulties, sophisticated fine-tuning steps are applied to the lithography projection apparatus, design layout, or patterning apparatus. These fine-tuning steps include, but are not limited to, optimizing NA and optical coherence settings, customizing illumination schemes, using phase-shift patterning apparatus, 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). Summary of the Invention

[0009] A measurement system and method based on optical vortices are described. A radiation source is configured to irradiate a measurement target in one or more layers of a patterned substrate. The measurement target is configured to diffract the radiation from the radiation source and impart orbital angular momentum to the radiation from the radiation source. A radiation sensor is configured to generate a measurement signal based on the orbital angular momentum of the diffracted radiation received from the measurement target. The measurement signal includes alignment position information and / or overlay information of one or more layers. Advantageously, compared to existing measurement systems that only use phase or intensity information associated with the diffracted radiation, the orbital momentum angle of the diffracted radiation can carry additional information useful for generating more accurate measurements.

[0010] According to one embodiment, a measurement system is provided. The measurement system includes a radiation source configured to irradiate a measurement target in one or more layers of a patterned substrate. The measurement target is configured to diffract the radiation from the radiation source and impart orbital angular momentum to the radiation from the radiation source. The system includes a radiation sensor configured to generate a measurement signal based on the orbital angular momentum of the diffracted radiation received from the measurement target. The measurement signal includes alignment position information and / or overlay information of one or more layers.

[0011] In some embodiments, the radiation from the radiation source includes a Gaussian radiation beam or a vortex radiation beam.

[0012] In some embodiments, radiation from a radiation source is diffracted and imparts orbital angular momentum to the radiation from the radiation source to form a diffracted radiation beam having non-zero orbital angular momentum and / or having optical vortices.

[0013] In some embodiments, the system includes a vortex separator configured to split diffracted radiation having orbital angular momentum into even-numbered and odd-numbered orbital angular momentum components.

[0014] In some embodiments, the radiation sensor includes a first sensor configured to detect even-numbered orbital angular momentum components of diffracted radiation having orbital angular momentum, and a second sensor configured to detect odd-numbered orbital angular momentum components. In some embodiments, the first and second sensors include a first single-pixel photodetector and a second single-pixel photodetector, or a first camera and a second camera. In some embodiments, the first and second sensors include a first interferometer and a second interferometer.

[0015] In some embodiments, the system includes a measurement target. The measurement target is configured to generate a singularity in the phase of the diffracted beam. The measurement target may include, for example, a grating having a fork-shaped or vernier scale appearance. In some embodiments, the measurement target includes a first grating in a first portion of a layer of a patterned substrate and a second grating in a second adjacent portion of the patterned substrate. In some embodiments, the measurement target includes a first grating in a first layer of one or more layers of a patterned substrate and a second grating in a second layer of one or more layers of a patterned substrate. Together, these can form a grating having a fork-shaped or vernier scale appearance.

[0016] In some embodiments, the measurement target includes a fork-shaped grating in a single layer of a patterned substrate. In some embodiments, the measurement target includes a first fork-shaped grating in a first layer of one or more layers of the patterned substrate and a second fork-shaped grating in a second layer of one or more layers of the patterned substrate. The second fork-shaped grating may be rotated approximately 90 degrees relative to the first fork-shaped grating.

[0017] In some embodiments, the measurement signal is an alignment signal or an overlay signal.

[0018] In some embodiments, the radiation sensor is configured to detect the phase, intensity, wavelength and / or polarization, as well as the orbital angular momentum, of diffracted radiation received from the measurement target, and to generate a measurement signal based on the orbital angular momentum and the phase, intensity, wavelength and / or polarization.

[0019] In some embodiments, the system includes one or more processors configured to determine the alignment and / or overlay of one or more layers based on measurement signals. In some embodiments, the one or more processors are configured to filter and separate diagonal and off-diagonal orders of diffracted radiation with orbital angular momentum from a measurement target, wherein the diagonal order has an even number of optical vortices and the off-diagonal order has an odd number of optical vortices, or vice versa. In some embodiments, the one or more processors are configured to filter and separate to avoid crosstalk.

[0020] In some embodiments, the measurement target differs from structures in one or more layers that are adjacent to, near, and / or surrounding the measurement target and cannot generate diffractive vortex beams.

[0021] In some embodiments, alignment and / or overlay information of one or more layers includes an indication of the shape changes of the diffracted radiation vortex beam in the measurement signal.

[0022] In some embodiments, the system includes one or more splitter cubes, prisms, mirrors, and / or lenses configured to receive diffracted radiation with orbital angular momentum from a measurement target and to direct the received diffracted radiation with orbital angular momentum toward a radiation sensor. In some embodiments, the one or more splitter cubes, prisms, mirrors, and / or lenses form a first path for the even-numbered orbital angular momentum components and a second path for the odd-numbered orbital angular momentum components of the diffracted radiation with orbital angular momentum.

[0023] In some embodiments, the measurement signal is configured to be used by one or more processors to regulate the semiconductor device manufacturing process.

[0024] According to another embodiment, a corresponding measurement method is provided, which includes one or more of the operations described above. Attached Figure Description

[0025] The above aspects and other aspects and features will become apparent to those skilled in the art after reading the following detailed description of specific embodiments in conjunction with the accompanying drawings.

[0026] Figure 1 A lithography apparatus according to an embodiment is schematically shown.

[0027] Figure 2 An embodiment of a photolithography unit or cluster according to an example is illustrated schematically.

[0028] Figure 3 An example inspection system according to an embodiment is illustrated schematically.

[0029] Figure 4 An example measurement technique according to an embodiment is illustrated schematically.

[0030] Figure 5 The relationship between the radiation irradiation point and the measurement target of the inspection system according to an embodiment is shown.

[0031] Figure 6 A system configured according to an embodiment to generate a measurement signal based on the orbital angular momentum of diffracted radiation received from a measurement target is shown.

[0032] Figure 7 An example of diffracted radiation with orbital angular momentum according to an embodiment is shown.

[0033] Figure 8Several different example measurement target gratings (showing gradually defined fork gratings) associated with different topological charges m for first-order diffracted radiation with different angular momentum and corresponding end-view intensity patterns are shown according to embodiments.

[0034] Figure 9 Examples of vernier scale appearance and fork shape that can be used to measure targets according to embodiments are shown.

[0035] Figure 10 An example vortex separator, according to an embodiment, is shown configured to separate diffracted radiation having orbital angular momentum into even-numbered and odd-numbered orbital angular momentum components.

[0036] Figure 11 The illustration shows how the intensity changes on the two detectors when a radiation beam strikes a fork-shaped grating, which diffracts the beam and imparts orbital angular momentum, according to an embodiment.

[0037] Figure 12 An example of a measurement target according to an embodiment is shown, the measurement target comprising a first grating in a first layer of one or more layers of a patterned substrate and a second grating in a second layer of one or more layers of a patterned substrate (rotated 90 degrees relative to each other in this example), which together may form a grating having a forked shape and / or some other geometry.

[0038] Figure 13 The illustration shows how the diagonal diffraction order changes the vortex state from odd to even or from even to odd when the target grating is aligned and misaligned, according to an embodiment.

[0039] Figure 14 The diagram illustrates the measurement target according to an embodiment, the intensity pattern of diffracted radiation with orbital angular momentum, and the corresponding pattern of topological charge.

[0040] Figure 15 A measurement method according to an embodiment is shown.

[0041] Figure 16 This is a block diagram of an example computer system according to an embodiment. Detailed Implementation

[0042] In semiconductor device manufacturing, metrology operations typically involve determining the location of measurement markers (or multiple markers) and / or other targets within layers of the semiconductor device structure. This location is usually determined by irradiating the measurement markers with radiation and comparing the characteristics of different diffraction orders of the radiation reflected from the measurement markers. These techniques are used to measure overlay, alignment, and / or other parameters.

[0043] Optical vortex-based measurement systems and / or methods utilizing diffracted radiation with orbital angular momentum are advantageous for a number of reasons. For example, the orbital angular momentum of diffracted radiation can carry additional information useful for generating more accurate measurements (compared to the information carried by diffracted radiation in existing systems) compared to existing measurement systems that only use phase or intensity information. Diffracted radiation with orbital angular momentum has zero or near-zero sensitivity to the structure of adjacent measurement marks in a patterned substrate. If beams with different orbital angular momentum are separated, there is generally no (or very little) crosstalk between diffraction orders. The orbital angular momentum is preserved as it propagates through lenses, apertures, and / or other components of the measurement system. A phase map provides a stable measurement of the orbital angular momentum. Diffracted radiation with orbital angular momentum is less sensitive to noise, less sensitive to aberrations, and less sensitive to alignment problems compared to typical diffracted radiation. Diffracted radiation with orbital angular momentum also enables the use of smaller measurement marks and / or enables overfilling of these marks. Diffracted radiation with orbital angular momentum can also work with multiple measurement target spacings and multiple radiation wavelengths, and can be detected using camera-based and / or interferometric-based detection techniques.

[0044] The following description, with a brief introduction, pertains to semiconductor device fabrication and patterning processes. The following paragraphs also describe several components of systems and / or methods used for semiconductor device measurement. These systems and methods can be used, for example, to measure overlay, alignment, etc., in semiconductor device fabrication processes, or for other operations.

[0045] While specific references may be made herein to measurements of overlay, alignment, or other parameters, and to the fabrication of integrated circuits (ICs) for semiconductor devices, it should be understood that the description herein has many other possible applications. For example, it can be used to fabricate integrated optical systems, guide and detection patterns for magnetic domain memories, liquid crystal displays, thin-film magnetic heads, etc. 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.

[0046] The term "projection optical system" as used herein should be interpreted broadly to include various types of optical systems, such as refractive optical systems, reflective optical systems, and aperture and antirefractive optical systems. The term "projection optics" may also include components that operate according to any of these design types for guiding, shaping, or controlling a projected radiation beam, either jointly or individually. The term "projection optics" can include any optical component in a lithographic projection apparatus, regardless of where the optical component is located in the optical path of the lithographic projection apparatus. Projection optics can include optical components for shaping, modulating, and / or projecting radiation from a source before it passes through a patterning device, and / or for shaping, modulating, and / or projecting radiation after it has passed through a patterning device. Projection optical systems typically do not include a light source and a patterning device.

[0047] Figure 1 An 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 device (e.g., a mask) MA and connected to a first positioner PM configured to precisely position the patterning device 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 precisely 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 device MA onto a target portion C (e.g., comprising one or more dies, and generally referred to as a field) of the substrate W. The projection system is supported on a reference frame RF. As shown, the apparatus is transmissive (e.g., employing a transmissive mask). Alternatively, the device can be reflective (e.g., using a programmable array of mirrors or a reflective mask).

[0048] The irradiator IL receives a radiation beam from the radiation source SO. The source and the lithography apparatus can be separate entities, for example, when the source is an excimer laser. In this case, the source is not considered part of the lithography apparatus, and the radiation beam is delivered from the source SO to the irradiator IL with the aid of a beam transmission system BD, which includes, for example, suitable guide mirrors and / or beam expanders. In other cases, the source can be a component of the apparatus, for example, when the source is a mercury lamp. The source SO and the irradiator IL, along with the beam transmission system BD (if desired), can be referred to as the radiation system.

[0049] An illuminator (IL) can alter the intensity distribution of a beam. The illuminator can be arranged to limit the radial range of the radiation beam such that the intensity distribution within the annular region of the pupil plane of the illuminator (IL) is non-zero. Alternatively, the illuminator (IL) can be used to limit the beam distribution within the pupil plane such that the intensity distribution within multiple equidistant sectors of the pupil plane is non-zero. The intensity distribution of the radiation beam within the pupil plane of the illuminator (IL) can be referred to as the illumination mode.

[0050] An illuminator IL may include a modulator AD configured to adjust the (angular / spatial) intensity distribution of a 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 outer σ and inner σ, respectively) can be adjusted. The illuminator IL can be used to change the angular distribution of the beam. For example, the illuminator can be used 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 multi-pole distribution, such as a dipole, tetrapole, or hexapole distribution. For example, a desired illumination mode can be obtained by inserting an optics providing the desired illumination mode into the illuminator IL or by using a spatial light modulator.

[0051] An illuminator IL can be used to change the polarization of the beam and can be used to adjust the polarization using a modulator AD. The polarization state of the radiation beam on the pupil plane of the illuminator IL can be called a polarization mode. The use of different polarization modes can achieve 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 on 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 according to the illuminator mode. For multi-pole illuminator modes, the polarization of each pole of the radiation beam is typically 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 bisecting the two opposing sectors of the dipole. The radiation beam can be polarized in one of two different orthogonal directions, which can be called X-polarization and Y-polarization states. For quadrupole illuminator modes, 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, in a hexapolar illumination mode, 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.

[0052] In addition, the irradiator IL typically includes various other components, such as an integrator In and a concentrator 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. Therefore, the irradiator provides a regulated radiation beam B with a desired uniformity of cross-section and intensity distribution.

[0053] The support structure MT supports the patterning apparatus in a manner dependent on the orientation of the patterning apparatus, the design of the lithography equipment, and other conditions (e.g., whether the patterning apparatus is held in a vacuum environment). The support structure can use mechanical, vacuum, electrostatic, or other clamping techniques to secure the patterning apparatus. The support structure can be, for example, a frame or stage, which may be fixed or movable 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 terms "mask" or "mask" can be considered synonymous with the more general term "patterning apparatus".

[0054] The term "patterning device" as used herein should be interpreted broadly as any device that can be used to impart a pattern to a target portion of a substrate. In one embodiment, a patterning device is any device that can be used to impart a pattern to a radiation beam in the cross-section of the radiation beam 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 applied to the radiation beam may not perfectly correspond to the desired pattern in the target portion of the substrate. Typically, the pattern applied to the radiation beam will correspond to a specific functional layer in the device created in the target portion of the device, such as an integrated circuit.

[0055] Patterning devices can be transmissive or reflective. Examples of patterning devices 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. One example of a programmable mirror array employs a matrix arrangement of small mirrors, each of which can be individually tilted to reflect an incident radiation beam in different directions. The tilted mirrors impart a pattern in the radiation beam, which is then reflected by the mirror matrix.

[0056] The term "projection system" should be interpreted broadly to include any type of projection system, including refractive, reflective, catadioptric, magnetic, electromagnetic, and electrostatic optical systems, or any combination thereof, depending on the exposure radiation or other factors used (such as the use of immersion liquids or vacuum). Any use of the term "projection lens" can be considered synonymous with the more general term "projection system".

[0057] A 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 on the pupil plane throughout the field of view). To achieve this, the adjustment mechanism may 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 used for any combination of the following operations: displacing one or more optical elements; tilting one or more optical elements; and / or deforming one or more optical elements. 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 away from a plane perpendicular to the optical axis, although rotation about the z-axis can be used for non-rotationally symmetric aspherical optical elements. 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 force 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 variations on the pupil plane). When designing a patterning device (e.g., a mask) MA for a lithography apparatus LA, the transmission map of the projection system PS can be used. Using computational lithography techniques, the patterning device MA can be designed to at least partially correct apodization.

[0058] Photolithography equipment can be of the type having two (dual-stage) or more supports or stages (e.g., two or more substrate stages WTa, WTb, two or more patterning device stages, WTb and substrate stage WTa located below the projection system without dedicated substrates for purposes such as 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 exposure is performed using one or more other stages. For example, alignment measurements can be performed using an alignment sensor AS and / or horizontal (height, tilt, etc.) measurements can be performed using a level sensor LS.

[0059] Photolithography apparatuses can also be of the type in which at least a portion of the substrate can be covered by a liquid (e.g., water) with a relatively high refractive index to fill the space between the projection system and the substrate. Immersion liquids can also be applied to other spaces within the photolithography apparatus, such as between the patterning apparatus and the projection system. Immersion techniques are well known in the art for increasing the numerical aperture of a projection system. The term "immersion" as used herein does not imply that the structure (such as the substrate) must be submerged in the liquid, but simply that the liquid is located between the projection system and the substrate during exposure.

[0060] In the operation of a photolithography apparatus, a radiation beam is regulated and provided by an irradiation system IL. The radiation beam B is incident on a patterning device (e.g., a mask) MA held on a support structure (e.g., a mask stage) MT and patterned by the patterning device. After passing through the patterning device MA, the radiation beam B passes 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, 2-D encoder, or capacitive sensor), the substrate stage WT can be precisely moved, for example, to position different target portions C within the path of the radiation beam B. Similarly, the first positioner PM and another position sensor (… Figure 1 (Not explicitly shown) can be used to precisely position the patterning device MA relative to the path of the radiation beam B, for example, after a mechanical retrieval from a mask library, or during scanning. Typically, movement of the support structure MT can be achieved by means of a long-stroke module (coarse positioning) and a short-stroke module (fine positioning) forming part of the first positioner PM. Similarly, movement of the substrate stage WT can be achieved using a long-stroke module and a short-stroke module 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 device MA and the substrate W can be aligned using patterning device alignment marks M1, M2 and substrate alignment marks P1, P2. Although the substrate alignment marks shown occupy dedicated target portions, they can be located in the space between the target portions (these are called scribing alignment marks). Similarly, in the case where multiple dies are provided on the patterning device MA, the patterning device alignment marks can be located between the dies.

[0061] The depicted 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 the pattern applied to the 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, thereby allowing exposure of different target portions C. In stepping mode, the maximum size of the exposure field is limited to 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 applied to the 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 magnification (reduction) 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 the non-scanning direction) during a single dynamic exposure, 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 remains essentially stationary to hold the programmable patterning device, and the substrate stage WT is moved or scanned while the pattern applied to the radiation beam is projected onto the target portion C. In this mode, a pulsed radiation source is typically used, and the programmable patterning device 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 utilizing programmable patterning devices such as programmable mirror arrays of the type described above.

[0062] Alternatively, combinations and / or variations of the above usage patterns, or entirely different usage patterns, may be adopted.

[0063] The substrate can be processed before or after exposure, for example in a track (a tool that typically applies a resist layer to the substrate and develops the exposed resist) or in a measurement or inspection tool. Where applicable, this disclosure herein can be applied to such and other substrate processing tools. Furthermore, the substrate can be processed multiple times, for example to create a multilayer IC; therefore, the term substrate as used herein can also refer to a substrate that already includes multiple processed layers.

[0064] The terms “radiation” and “beam” used in this article in relation to photolithography include all types of electromagnetic radiation, including ultraviolet (UV) or deep ultraviolet (DUV) radiation (e.g., wavelengths of 365, 248, 193, 157, or 126 nm) and extreme ultraviolet (EUV) radiation (e.g., wavelengths in the range of 5–20 nm), as well as particle beams, such as ion beams or electron beams.

[0065] Various patterns on or provided by a patterning apparatus can have different process windows, i.e., the processing variable space under which the pattern is generated within a specification. Examples of pattern specifications associated with potential systematic defects include checking for necking, line pullback, line thinning, CD, edge placement, overlap, resist top loss, resist undercut, and / or bridging. The process windows of patterns on a patterning apparatus or its area can be obtained by merging (e.g., overlapping) the process windows of each individual pattern. The boundary of the process windows of a set of patterns includes the boundary of the process windows of some individual patterns. In other words, these individual patterns limit the process windows of the set of patterns.

[0066] like Figure 2 As shown, a lithography apparatus LA can form part of a lithography unit LC, sometimes referred to as a lithography unit or cluster, which also includes equipment for performing pre- and post-exposure processes on a substrate. Traditionally, these apparatuses include one or more spin coaters SC for depositing one or more resist layers, one or more developers for developing the resist after exposure, one or more chill plates CH, and / or one or more baking plates BK. A substrate transporter or robot RO picks up one or more substrates from input / output ports I / O1, I / O2, moves the substrates between different processing units, and delivers the substrates to the loading area LB of the lithography apparatus. These units (often collectively referred to as tracks) are controlled by a track control unit TCU, which in turn is controlled by a monitoring system SCS, which in turn controls the lithography apparatus via the lithography control unit LACU. Therefore, different units can be operated to maximize yield and processing efficiency.

[0067] To ensure correct and consistent exposure of the substrate exposed by the lithography equipment and / or to monitor a portion of a patterning process (e.g., a device fabrication process) that includes at least one pattern transfer step (e.g., an optical lithography step), it is necessary to examine the substrate or other object to measure or determine one or more properties, such as alignment, overlay (e.g., between structures in an overlay layer, or between structures in the same layer that are individually provided to the layer via a dual patterning process), line thickness, critical dimension (CD), focus offset, material properties, etc. Therefore, the manufacturing facility housing the lithography unit LC typically also includes a metrology system for measuring portions or all of the substrate W (which has already been processed in the lithography unit) Figure 1 The measurement system can be part of the lithography unit (LC), for example, it can be part of the lithography apparatus (LA) (such as the alignment sensor AS). Figure 1 )).

[0068] One or more measurement 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 in or on a patterned substrate, focusing or focusing errors of the optical lithography step, dose or dose error of the optical lithography step, optical aberrations of the optical lithography step, etc. Such measurements are typically performed on one or more dedicated measurement targets provided on the substrate. These measurements may be performed after resist development but before etching, after etching, after deposition, and / or at other times.

[0069] Various techniques are available for measuring structures formed in patterning processes, including the use of scanning electron microscopy, image-based measurement tools, and / or various specialized instruments. In a rapid and non-invasive specialized metrology instrument, radiation is directed onto a target on the substrate surface, and the characteristics of the scattered (diffracted / reflected) beam are measured. By evaluating one or more characteristics 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 metrology. Applications of such diffraction-based metrology include measurements of overlay, alignment, etc. For example, overlay and / or alignment can be measured by comparing portions of diffraction spectra (e.g., comparing different diffraction orders in the diffraction spectrum of a periodic grating).

[0070] Therefore, in device fabrication processes (e.g., patterning or photolithography), substrates or other objects may undergo various types of measurements during or after the process. Measurements can determine whether a particular substrate has defects, can adjust the process and the equipment used in the process (e.g., aligning two layers on a substrate, or aligning a patterned device with a substrate), can measure the performance of the process and equipment, or can 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 ASML Orion, YieldStar, and / or SMASH metrology systems), mechanical measurements (e.g., profilometry using styluses, atomic force microscopy (AFM)), and / or non-optical imaging (e.g., scanning electron microscopy (SEM)).

[0071] Measurement results can be provided directly or indirectly to the monitoring 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 enough so that one or more other substrates in the batch still need to be exposed) and / or to the subsequent exposure of the exposed substrate. Furthermore, already exposed substrates can be stripped and reworked to improve yield, or discarded, thus avoiding further processing of substrates known to be defective. In cases where only some target portions of the substrate are defective, further exposure can be performed only on the compliant target portions. Other manufacturing process adjustments are also considered.

[0072] Measurement systems can be used to determine one or more properties of a substrate structure, particularly how one or more properties vary across different substrate structures, or how different layers of the same substrate structure vary layer by layer. Measurement systems can be integrated into lithography equipment (LA) or lithography units (LC), or they can be stand-alone devices.

[0073] To enable measurement, one or more targets are typically provided specifically on a substrate. Typically, the targets are specially designed and may include periodic structures. For example, targets on the substrate may include one or more 1-D periodic structures (e.g., geometric features such as gratings) that are printed such that, after development, the periodic structural features are formed by solid resist lines. As another example, targets may include one or more 2-D periodic structures (e.g., gratings) that are printed such that, after development, one or more periodic structures are formed by solid resist pillars or vias in the resist. The strips, pillars, or vias may alternatively be etched into the substrate (e.g., etched into one or more layers on the substrate).

[0074] Figure 3 An example measurement (inspection) system 10 is depicted that can be used for detecting alignment, overlay, and / or performing other measurement operations. It includes a radiation source or irradiation source 2 for projecting or otherwise irradiating radiation onto a substrate W (e.g., which may typically include measurement marks). The redirected radiation is passed to a sensor, such as a spectrometer detector 4 and / or other sensors, which measure the spectrum (intensity as a function of wavelength) of the radiation from specular reflection and / or diffraction, such as... Figure 4 As shown in the figure on the left. The sensor can generate a measurement signal that conveys measurement data indicating the characteristics of the reflected radiation. Based on this data, the structure or profile of the detected spectrum can be reconstructed through one or more processors or other operations.

[0075] and Figure 1 Similar to the lithography equipment LA in [the context of lithography], it can provide one or more substrate stages to hold the substrate W during measurement operations. The one or more substrate stages can be in the same form as [other types of lithography equipment]. Figure 1The substrate stages WT (WTa or WTb or both) are similar or identical. In the example where system 10 is integrated with a lithography apparatus, they can even be the same substrate stages. Coarse and fine positioners can be provided and configured to precisely 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., measurement markers) and to position it below the objective. Typically, many measurements will be taken of the target portion of the structure at different locations across the substrate W. The substrate support can be moved in the X and Y directions to obtain different targets, and also in the Z direction to obtain the desired position of the target portion relative to the focus of the optics. When, for example, in practice, the optics can remain substantially stationary (typically in the X and Y directions, but also in the Z direction) and the substrate moves, it is convenient to bring the objective to different positions relative to the substrate to think about and describe the operation. Provided the relative positions of the substrate and the optical system are correct, it does not matter in principle which one of them is moving, or both of them are moving, or a part of the optical system is moving (e.g., in the Z and / or tilt directions) while the rest of the optical system is stationary, and the substrate is moving (e.g., in the X and Y directions, but optionally in the Z and / or tilt directions).

[0076] For typical metrological measurements, the target 30 on the substrate W can be a 1-D grating, which is printed such that, after development, the stripe is formed by solid resist lines (e.g., which may be covered by a deposited 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 by solid resist pillars and / or other features in the resist.

[0077] Strips, 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. Targets 30 (e.g., stripes, pillars, vias, etc.) are sensitive to processing variations in the patterning process (e.g., optical aberrations in a photolithography projection apparatus (such as optical distortions in a projection system), focus variations, dose variations, etc.), causing process variations to manifest as variations in targets 30. Therefore, measurement data from targets 30 can be used to determine adjustments to one or more manufacturing processes and / or serve as the basis for actual adjustments.

[0078] For example, measurement data from target 30 can indicate the alignment and / or overlay of layers in 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 alignment and / or overlay, and to determine adjustments to semiconductor device manufacturing equipment based on the determined one or more semiconductor device manufacturing process parameters. In some embodiments, this can include, for example, stage position adjustment, or it can include determining adjustments to 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.

[0079] Figure 5 The diagram illustrates a plan view of a typical measurement target 30, and... Figure 3 The typical range of the radiation irradiation point 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 irradiation point S. The width of point S can be smaller than the width and length of the target. In other words, the target is irradiated "underfilled," and the diffraction signal is substantially unaffected by any signals such as product features outside the target itself. For example, the irradiation arrangement can be configured to provide uniform intensity irradiation across the back focal plane of the objective. Alternatively, for example, irradiation can be restricted from the axial or off-axis directions by including a spot size selector in the irradiation path.

[0080] Figure 6 A system 600 configured to generate a measurement signal based on the orbital angular momentum of diffracted radiation received from a measurement target is shown. Note that system 600 is merely a representative example of several different possible types of systems that can utilize diffracted radiation with orbital angular momentum (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 Orion system and / or other systems. System 600 is related to the above references. Figure 3 The system described is the same as or similar to system 10, and one or more components of system 600 are similar to and / or the same as one or more components of system 10. Figure 6 Several possible additional components of the system are shown. In some embodiments, one or more components of system 600 may replace one or more components of system 10, be used with one or more components of system 10, and / or otherwise expand one or more components of system 10. System 600 includes a radiation source 612 (e.g., with...). Figure 3 The source 2 shown is similar to and / or the same as the source 2 shown), and (one or more) sensors 604 (e.g., with Figure 3The sensor shown is similar to and / or identical to 4), and one or more processors PRO (with Figure 3 The processor PRO shown is similar to and / or identical to that shown, as well as various lenses, beam splitters, and / or other components (e.g., see various unlabeled boxes in system 600). One or more processor PROs are operatively connected to sensor 604 and / or other components of system 600.

[0081] Figure 6 The illumination branch 625 of the system 600 is shown to include: a radiation source 612; a detection branch 660, which includes one or more sensors 604 and one or more processors PRO; an objective lens 690; and / or other components. In some embodiments, the components of the system 600 are configured as part of an alignment and / or overlay sensor in a semiconductor manufacturing process.

[0082] Figure 6 Measurement targets 30 are also shown, which may include one or more measurement marks formed in a substrate 602, such as a semiconductor wafer, such as diffraction grating targets, collectively referred to as measurement targets 30. Target 30 may include one or more structures in a patterned substrate capable of providing diffraction signals with orbital angular momentum. One or more targets 30 may be included in a single layer and / or multiple (e.g., two) layers of a substrate, such as a semiconductor device structure. In some embodiments, features include geometric features such as 1D or 2D features, and / or other geometric features. By way of several non-limiting examples, the feature may include gratings, lines, edges, lines and / or edges of fine pitch series, and / or other features. More information regarding measurement targets 30 is described below.

[0083] Various lenses ( Figure 6 The exemplary objective lens 690, reflectors, beam splitters, and other optical components are configured to receive, emit, reflect, focus, and / or perform other operations on illumination generated by illumination source 612, received by detection branch 660, and / or used by other parts of system 600. These various lenses, reflectors, beam splitters, and / or other optical components may include any type of lens, reflector, beam splitter, and / or optical component configured to allow system 600 to function as described. For example, system 600 may include one or more beam splitters in detection branch 660 configured to separate radiation between polarization and overlapping diffraction orders, and / or configured to separate radiation with different orbital angular momentum, thereby creating two phase and two orbital angular momentum channels for each polarization.

[0084] As another example, objective lens 690 can be formed of any transparent material and has a curved surface configured to focus or otherwise concentrate one or more radiation points onto target(s)30(s). Various lenses, reflectors, optics, beam splitters, and other optical elements can be positioned at any location and / or at any angle relative to each other that allows system 600 to function as described herein. This can include positioning at specific relative distances between elements, specific angles between elements, etc. In some embodiments, various lenses, reflectors, optics, beam splitters, and other optical components are positioned relative to each other in system 600 via structural members, clips, clamps, screws, nuts, bolts, adhesives, and / or other mechanical means. In some embodiments, individual components of lenses, reflectors, optics, beam splitters, and other optical elements can be moved relative to each other. For example, movement can be configured to adjust the position of a corresponding irradiated spot on one or more targets 30. In some embodiments, movement includes tilting, translating, or otherwise changing the distance between various lenses, reflectors, and other optical components. Other examples of movement are also contemplated.

[0085] In some embodiments, movement can be electronically controlled by a processor (e.g., processor PRO). The processor PRO may be included in a computing system CS ( Figure 16 In, and may be based on computer or machine-readable instructions (e.g., as follows regarding) Figure 16 The system operates as described. Electronic communication can occur by transmitting electronic signals between separate components, transmitting data between separate components of system 600, transmitting values ​​between separate components, and / or other communications. Components of system 600 can communicate wirelessly via wired or network (e.g., the Internet or a combination of the Internet and various other networks, such as local area networks, cellular networks, personal area networks, internal organizational networks, and / or other networks).

[0086] In some embodiments, one or more actuators ( Figure 6 (Not shown) Actuators may be coupled to one or more components of system 600 and configured to move the one or more components. These actuators may be attached to one or more components of system 600 by adhesives, clips, clamps, screws, collars and / or other mechanisms. These actuators may be configured to be electronically controlled. Each actuator may be configured to convert an electrical signal into a mechanical displacement. The mechanical displacement is configured to move a component of system 600. For example, one or more actuators may be piezoelectric. One or more processors PRO may be configured to control these actuators. One or more processors PRO may be configured to individually control each of the one or more actuators.

[0087] Figure 6The number of lenses, reflectors, and / or other optical components shown is not 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 components.

[0088] Radiation source 612 is configured to generate radiation. Radiation may include illumination, such as light and / or other radiation. In some embodiments, radiation from radiation source 612 includes a Gaussian radiation beam, a vortex 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, radiation includes light and / or other radiation. In some embodiments, light includes visible light, infrared light, near-infrared light, and / or other light. In some embodiments, radiation may be any radiation suitable for interferometric measurements.

[0089] Measurement targets 30 in one or more layers of patterned substrate 602 are configured to be irradiated. Measurement targets 30 are configured to diffract the radiation and impart orbital angular momentum to the radiation. The diffraction and imparting of orbital angular momentum to the radiation forms a diffracted radiation beam with non-zero orbital angular momentum. For example, the beam may have optical vortices. In some embodiments, the measurement target 30 configured to diffract radiation from a radiation source and impart orbital angular momentum to the radiation from the radiation source differs from structures adjacent to, near, and / or surrounding the measurement target in one or more layers that cannot generate diffracted vortex beams.

[0090] As a non-restrictive example, Figure 7 An example of diffracted radiation 700 with orbital angular momentum is shown. Figure 7 The beam 702, which has no orbital angular momentum (and thus appears as a series of flat plates), is compared with beams 704, 706, 708, and 710, each with a different amount of orbital angular momentum. Since the total orbital angular momentum is conserved, the sum of the orbital angular momentum of the positive and negative diffraction orders is equal to the orbital angular momentum of the incident beam. Figure 7Perspective view 711 and end view 712 are shown, along with end view intensity pattern 714 for each beam. End view intensity pattern 715 shows how beams 704, 706, 708, and 710 each possess optical vortices. For example, the dark circle at the center of each image represents an optical vortex. An optical vortex can be considered a singularity. In an optical vortex, light twists around its axis of travel in a spiral motion. When projected onto a flat surface, an optical vortex appears as a halo with a dark aperture at its center (see end view intensity pattern and phase pattern). A number is given to the vortex based on the number of times the light twists at one wavelength; this number is called the topological charge m. The topological charge m is an integer and can be positive or negative, depending on the direction of the twist. The greater the number of twists, the faster the light rotates around its axis. m=0 represents a beam with no orbital angular momentum.

[0091] Figure 8 Several different example measurement targets 30 gratings 800, 802, 804, 806, 808 (which show gradually defined fork-shaped gratings in a single layer of a substrate) are illustrated, along with corresponding end-view intensity patterns 810 associated with different topological charges m of first-order diffracted radiation with different angular momentum. The end-view intensity pattern 810 varies with the topological charges shown, as well as the diffraction order and / or other factors. Therefore, the end-view intensity pattern 810 can be used for measurement (e.g., detecting and / or separating different diffraction orders, etc.).

[0092] Back Figure 6 In some embodiments, the measurement target 30 may include a fork-shaped (e.g., as shown in the image) Figure 8 The measurement target 30 includes a fork-shaped grating in a single layer of a substrate; a first grating in a first portion of a layer of a patterned substrate and a second grating (with slightly different periods) in a second adjacent portion of a layer of a patterned substrate; or a first grating in a first layer of one or more layers of a patterned substrate and a second grating in a second layer of one or more layers of a patterned substrate; together they form a grating having a fork-shaped or vernier scale appearance. In some embodiments, the target 30 includes a fork-shaped grating in a single layer of a patterned substrate; or a first fork-shaped grating in a first layer of one or more layers of a patterned substrate and a second fork-shaped grating in a second layer of one or more layers of a patterned substrate, wherein the second fork-shaped grating is rotated approximately 90 degrees relative to the first fork-shaped grating.

[0093] Figure 9 It shows what can be used to measure target 30 ( Figure 6 Examples of the appearance of vernier scale 900 and fork-shaped 902 (see dashed ellipse). Vernier scale 900 in Figure 9The image is shown in a top view. In this example, the vernier scale 900 includes a first grating 910 in a first portion 912 of the layer of the patterned substrate 602 and a second grating 916 in a second adjacent portion 918 of the layer of the patterned substrate 602, which together form a grating having the appearance of the vernier scale 900. The gratings 910 and 916 have different periodicities relative to each other, which creates diffracted radiation with orbital angular momentum as described above.

[0094] exist Figure 9 The top view shows a fork-shaped 902 grating 920. The fork-shaped 902 grating 920 can be formed from a single grating in a single layer of a patterned substrate, and / or can be formed from different gratings in different layers, when... Figure 9 When viewed in the top view shown, different gratings in different layers form a fork-shaped 902 grating 920 when aligned. For example, in some embodiments, the fork-shaped 902 grating 920 may be formed by two vernier scale 900 gratings in two different layers that are shifted relative to each other. The fork-shaped 902 grating 920 is configured such that when an incident light beam illuminates the fork-shaped 902 grating 920, the light beam diffracted from the fork-shaped 902 grating 920 will have an optical vortex.

[0095] Back Figure 6 Sensor 604 (which can be a separate sensor or one of the same sensors, even if they are in Figure 6 (Shown separately) is configured to receive diffracted radiation from target 30 and generate a measurement signal. The measurement signal is generated based on the orbital angular momentum and / or other information of the diffracted radiation received from target 30. In some embodiments, radiation sensor 604 is configured to detect the phase, intensity, wavelength and / or polarization, and orbital angular momentum of the diffracted radiation received from target 30, and generate a measurement signal based on the orbital angular momentum and phase, intensity, wavelength and / or polarization.

[0096] In some embodiments, the measurement signal includes measurement information relating to the measurement target 30. For example, the measurement signal may be an overlay and / or alignment signal that includes overlay and / or alignment measurement information, and / or other measurement signals. The measurement information (e.g., overlay values, alignment values, and / or other information) may be determined using the principles of interferometry and / or other principles. In some embodiments, the alignment position information and / or overlay information of one or more layers included in the measurement information includes an indication of the shape changes of the diffracted radiation vortex beam in the measurement signal.

[0097] The measurement signal includes an electronic signal that represents and / or otherwise corresponds to radiation reflected from target 30. The measurement signal may indicate, for example, measurements and / or other information associated with a diffraction grating. Generating the measurement signal includes sensing the diffracted radiation and converting the sensed diffracted radiation into an electrical signal. In some embodiments, generating the measurement signal includes sensing different portions of diffracted radiation from different regions and / or different geometries of target 30 and / or multiple targets, and combining the different portions of reflected radiation to form the measurement signal. This may include generating and / or analyzing one or more images of target 30 using the radiation described herein.

[0098] In some embodiments, system 600 is configured to receive diffracted radiation with orbital angular momentum from measurement target 30 using one or more beam splitters, prisms, mirrors, and / or lenses, and to direct the received diffracted radiation with orbital angular momentum toward a radiation sensor (e.g., 604). For example, in some embodiments, system 600 includes a vortex sorter, such as... Figure 10 The vortex sorter 1000 is shown. The sorter 1000 is shown in top view 1003. In the sorter 1000, diffracted radiation 1002 having orbital angular momentum is separated into even-numbered orbital angular momentum components 1004 and odd-numbered orbital angular momentum components 1006. Beam-splitting prisms 1010 and 1012, prisms 1014 and 1016, mirrors 1018 and 1020, lenses, and / or other components form a first path 1024 for the even-numbered orbital angular momentum component 1004 and a second path 1026 for the odd-numbered orbital angular momentum component 1006 of the diffracted radiation 1002 having orbital angular momentum. In some embodiments, a radiation sensor (e.g., see...) Figure 6 (As described above) includes a first sensor 1050 configured to detect even-numbered orbital angular momentum components 1004 of diffracted radiation 1002 having orbital angular momentum, and a second sensor 1052 configured to detect odd-numbered orbital angular momentum components 1006. In some embodiments, the first sensor and the second sensor 1050 and 1052 include a first single-pixel photodetector and a second single-pixel photodetector, a first camera and a second camera, a first interferometer and a second interferometer, and / or other sensors.

[0099] Figure 11 This illustrates when a radiation beam strikes a fork-shaped grating (e.g., Figure 9 When the fork-shaped grating 902 (as shown in the diagram) is used, two detectors (e.g., Figure 10The intensity on sensors 1050 and 1052 (shown in the diagram) varies, and the forked grating diffracts the beam, imparting orbital angular momentum as described above. As shown in the progression of images 1100, 1102, and 1104, the intensity pattern 1110 of the diffracted radiation changes from a single bright spot 1112 to bright spot 1114, where optical vortex 1116 is located at or near the center of bright spot 1114. This indicates that the radiation diffracted from the forked grating possesses orbital angular momentum. For example, images similar to and / or identical to image 1104 can be analyzed to determine alignment, overlay, and / or other measurements. Figure 11 In the images 1100, 1102, and 1104, the right-hand side shows the detected images of the even-numbered orbital angular momentum arms, while the left-hand side shows the odd-numbered orbital angular momentum arms. The modulation signal on each arm is observed as the marker is scanned, but the envelope of each signal depends on which region of the marker is illuminated. When at the center of the marker (top and bottom layers are on top of each other and do not bifurcate), most of the diffracted beam appears in the even-numbered arms (no orbital angular momentum), but when the marker is scanned and moved towards the center, where the top grating is in the middle of the bottom grating, most of the power is in the odd-numbered arms (vortex beams). The modulation signal is an alignment signal, and the center of the marker can be defined using a fitting algorithm. However, when adjacent structures are present, the modulation signal is shifted by a small amount (depending on the relative position of the marker and adjacent structures), resulting in alignment position deviation. But if the orbital angular momentum is separated, the alignment signal is insensitive to adjacent structures.

[0100] Figure 12 An example of a measurement target 30 comprising different portions oriented at 90 degrees to each other (in this example) is shown. In some embodiments, the different portions may exist in a single layer of a patterned substrate. In some embodiments, the different portions may include a first grating (e.g., as shown in the first layer of the patterned substrate) in a first layer of the patterned substrate. Figure 6 The patterned substrate 602 shown and the second grating in the second layer of the patterned substrate together form a grating 1200 with a fork shape 1202. For example, such a grating can be used for measuring overlay and / or determining other measurements. Similar gratings and / or similar arrangements can be used to form the aforementioned Vinyl scale appearance and / or some other geometry. Figure 12 In the image, the first forked grating and the second forked grating are rotated approximately 90 degrees relative to each other, but the first forked grating and the second forked grating are difficult to distinguish because grating 1200 is shown in the top view. Figure 12 This is one possible example. Other rotational amounts and / or other grating shapes and / or configurations that would allow this system and method to function as described are considered.

[0101] like Figure 12As shown, a pattern 1250 generates topological charges m (i.e., + / -1, + / -2, + / -3, and + / -4 in the diffracted radiation relative to each other rotating gratings (or portions of gratings). Pattern 1250 can be used to enhance alignment and / or overlay determination, and / or for other purposes. For example, pattern 1250 can be used to separate orbital angular momentum information from other information in the diffracted radiation, separate even and odd diffraction orders of the diffracted radiation (e.g., as indicated by the corresponding even and odd topological charges), and / or otherwise sort (using...) Figure 10 The sorter 1000 shown and described above, and / or may be used for other operations.

[0102] Figure 13 This illustrates the overlay application when two marks are located on two different layers; however, for alignment purposes, one or more marks may be located on the same layer, as shown below. Figure 14 As shown. For alignment applications, all diffraction orders impacting the sensor—with orbital angular momentum orders of +1 and -1—are the diffraction orders that define the alignment position. However, overlap of other diffraction orders (diagonal terms / angles) with the desired signal results in errors defining the alignment position. For overlay sensors, if overlay is present, the orbital angular momentum order is relevant for all orders ( Figure 13 The pattern varies depending on whether overlay is present. One or more diffraction orders can be used. The overlay pattern can be defined by measuring portions of light in different orbital angular momentum arms (as described above).

[0103] Figure 13 The diagonal diffraction order is shown when gratings 1304 and 1306 are aligned with 1310 and misaligned with 1320. Figure 13 The central diffraction order in the signal is also an undesirable signal, but something physically blocking it (usually included in the measurement system) can change their vortex state (e.g., the m-value) from odd to even or from even to odd. Figure 13 In this context, grating 1304 is a patterned substrate (e.g., as shown in the image). Figure 6 The first grating in the first layer of the patterned substrate 602 shown, and the second grating 1306 in the second layer of the patterned substrate, together form a forked grating. Figure 13 In this configuration, the first forked grating 1304 and the second forked grating 1306 are rotated approximately 90 degrees relative to each other. Misalignment (e.g., see 1320) is caused, for example, by a shift 1330 in grating 1306. Patterns 1300 and / or 1302, variations from one pattern to another, and / or other relevant data, can be used to enhance alignment and / or overlay determination, and / or can be used for other purposes, as described above. For example, changes in the patterns can indicate misalignment between layers (as associated with shift 1330 in this example), specific overlay values, etc.

[0104] In some embodiments, one or more processors (e.g., Figure 3 , Figure 6 and Figure 16 The PRO shown and described herein is configured to respond to measurements from target 30 ( Figure 6 The diagonal and off-diagonal orders of the diffracted radiation with orbital angular momentum are filtered and / or separated, where the diagonal order has an even number of optical vortices and the off-diagonal order has an odd number of optical vortices, or vice versa. Filtering and / or separation can be performed to avoid crosstalk and / or for other purposes. For example, Figure 14 The measurement target 30 is shown, along with an intensity pattern 1400 of diffracted radiation having orbital angular momentum and a corresponding pattern 1402 of topological charge. The intensity in the intensity pattern 1400 (e.g., the shape and shading of various circular patterns) varies with the corresponding topological charge. In this example, the target 30 includes a fork shape 1401 in both the vertical and horizontal directions. The radiation diffracted by the target 30 creates a diagonal diffraction order 1410 (i.e., even-numbered diffraction order) with an even number of topological charges and an off-diagonal order 1420 (i.e., odd-numbered diffraction order) with an odd number of topological charges. Sorter 1000 ( Figure 10 This can be used as a filter to separate diagonal and off-diagonal diffraction orders to avoid crosstalk and / or for other reasons. In this example, it is a 2D marker used to define the alignment of the marker in the X and Y axes. The marker can be scanned horizontally, vertically, or diagonally. A modulated signal similar to that of a 1D marker can be obtained, and the center of the marker can be defined by using a fitting algorithm.

[0105] Figure 15 Measurement method 1500 is illustrated. In some embodiments, method 1500 is performed, for example, as part of an overlay and / or alignment sensing operation in a semiconductor device manufacturing process. In some embodiments, one or more operations of method 1500 may be performed, for example, in... Figure 6 The system 600 shown Figure 3 System 10 shown, computer system (e.g., such as...) Figure 16The method 1500 may be implemented in or by means of the method shown and described below, and / or in other systems. In some embodiments, method 1500 includes radiating (operation 1502) a measurement target with radiation, such that the measurement target diffracts orbital angular momentum and imparts orbital angular momentum to the radiation; generating (operation 1504) a measurement signal based on the orbital angular momentum; and determining (operation 1506) alignment and / or overlay based on the measurement signal. The operation of method 1500 is illustrative. In some embodiments, method 1500 may be performed with one or more additional operations not described, and / or without one or more of the operations discussed. For example, in some embodiments, method 1500 may include additional operations that include determining adjustments to a semiconductor device manufacturing process. Additionally, the operation of method 1500 is described in... Figure 15 The order shown and described herein is not intended to be limiting.

[0106] In some embodiments, one or more portions of method 1500 may be implemented in and / or controlled by one or more processing devices (e.g., digital processors, analog processors, digital circuits designed to process information, analog circuits designed to process information, state machines, 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 1500 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 that are specifically designed to perform one or more operations of method 1500 (e.g., see below regarding...). Figure 16 (Discussion).

[0107] In operation 1502, a measurement target in one or more layers of a patterned substrate is irradiated with radiation. Operation 1502 may include generating radiation using a radiation source and one or more lenses and directing the radiation to the measurement target. In some embodiments, the radiation from the radiation source includes a Gaussian radiation beam, a vortex radiation beam, and / or other radiation. The patterned substrate may be, for example, a semiconductor wafer and / or other substrates. In some embodiments, method 1500 is configured for use on a semiconductor wafer and for use in a semiconductor manufacturing process.

[0108] The measurement target is configured to diffract radiation and impart orbital angular momentum to the radiation. The diffraction and impartation of orbital angular momentum to the radiation forms a diffracted radiation beam with non-zero orbital angular momentum. For example, the beam may have optical vortices. In some embodiments, the measurement target configured to diffract radiation from a radiation source and impart orbital angular momentum to the radiation from the radiation source differs from structures adjacent to, near, and / or surrounding the measurement target in one or more layers that cannot generate diffracted vortex beams.

[0109] In some embodiments, operation 1502 includes generating a singularity in the phase of the diffracted beam using a measurement target. The measurement target may include, for example, a grating having a fork-shaped or vernier scale appearance. In some embodiments, the measurement target includes a single grating in a single layer; a first grating and a second grating in adjacent portions of a single layer; a first grating in a first layer and a second grating in a second layer of one or more layers of a patterned substrate; and / or other configurations forming a grating having a fork-shaped or vernier scale appearance. In some embodiments, the measurement target includes a fork-shaped grating in a single layer; a first fork-shaped grating in a first layer of the one or more layers of the patterned substrate and a second fork-shaped grating in a second layer of the one or more layers of the patterned substrate, wherein the second fork-shaped grating is rotated approximately 90 degrees relative to the first fork-shaped grating; and / or other configurations. In some embodiments, operation 1502 is performed by... Figure 3 The radiation source 2 shown is Figure 6 The same or similar radiation sources as source 612, such as the same measurement targets as target 30 shown in the figure and / or the other components mentioned above, are used to perform the measurement.

[0110] In operation 1504, a measurement signal is generated based on the orbital angular momentum and / or other information of the diffracted radiation received from the measurement target. In some embodiments, operation 1504 includes receiving the diffracted radiation with orbital angular momentum from the measurement target using one or more beam splitters, prisms, mirrors, and / or lenses, and directing the received diffracted radiation with orbital angular momentum toward a radiation sensor. In some embodiments, operation 1504 includes using a vortex sorter to separate the diffracted radiation with orbital angular momentum into even-numbered and odd-numbered orbital angular momentum components. For example, one or more beam splitters, prisms, mirrors, and / or lenses may form a first path for the even-numbered orbital angular momentum component and a second path for the odd-numbered orbital angular momentum component of the diffracted radiation with orbital angular momentum.

[0111] In some embodiments, the measurement signal includes measurement information relating to one or more targets. For example, the measurement signal may be an overlay and / or alignment signal that includes overlay and / or alignment measurement information, and / or other measurement signals. The measurement information (e.g., overlay values, alignment values, and / or other information) can be determined using the principles of interferometry and / or other principles. In some embodiments, the alignment position information and / or overlay information of one or more layers included in the measurement information includes an indication of the shape changes of the diffracted radiation vortex beam in the measurement signal.

[0112] The measurement signal includes an electronic signal that represents and / or otherwise corresponds to radiation reflected from one or more targets. The measurement signal may indicate, for example, measurements and / or other information associated with a diffraction grating target. Generating the measurement signal includes sensing the reflected radiation and converting the sensed reflected radiation into an electrical signal. In some embodiments, generating the measurement 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 the reflected radiation to form the measurement signal. This may include generating and / or analyzing one or more images of the target using the radiation described herein.

[0113] Operation 1504 can be performed by... Figure 3 , Figure 6 and Figure 16 The detector 4, sensor 604, and / or processor PRO (described below) shown herein perform similar and / or identical radiation sensors and / or other components. In some embodiments, the radiation sensor includes a first sensor configured to detect even-numbered orbital angular momentum components of diffracted radiation having orbital angular momentum, and a second sensor configured to detect odd-numbered orbital angular momentum components. In some embodiments, the first and second sensors include a first and a second single-pixel photodetector, a first and a second camera, a first and a second interferometer, and / or other sensors.

[0114] In some embodiments, operation 1504 includes detecting reflected radiation from one or more diffraction gratings constituting a measurement target. In some embodiments, operation 1504 may include detecting the phase, intensity, wavelength, and / or polarization, as well as orbital angular momentum, of diffracted radiation received from the measurement target using a radiation sensor, and generating a measurement signal based on the orbital angular momentum and phase, intensity, wavelength, and / or polarization; based on marker positions (for alignment) and / or based on overlay between two layers of the target; and / or other information. In some embodiments, 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 target(s). 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 is different from the phase and / or amplitude of reflected radiation from the other side of the target.

[0115] 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 increments) and / or amplitude variations corresponding to different parts of the target. For example, radiation reflected 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. Detecting reflected radiation also includes measuring the phase and / or amplitude differences of reflected radiation at different diffraction orders. Detection of one or more local phase and / or amplitude shifts can be performed using, for example, Hilbert transform and / or other techniques. Interferometry techniques and / or other operations can be used to measure the phase and / or amplitude differences of reflected radiation at different diffraction orders.

[0116] In operation 1506, alignment and / or overlay of one or more layers of the substrate are determined based on measurement signals and / or other information. In some embodiments, operation 1506 is performed by... Figure 3 and Figure 6 One or more processors that are the same as or similar to the processor PRO shown are executed, and as described above (with) Figure 16 The processor PRO shown is described below. In some embodiments, the one or more processors are configured to filter and separate the diagonal order of diffracted radiation with even-numbered optical vortices and the off-diagonal order with odd-numbered optical vortices from the measurement target, or vice versa. The one or more processors may be configured to perform filtering and separation to avoid, for example, crosstalk and / or for other reasons.

[0117] In some embodiments, operation 1506 includes determining adjustments to a semiconductor device manufacturing process. In some embodiments, operation 1506 includes determining one or more semiconductor device manufacturing process parameters. These one or more semiconductor device manufacturing process parameters may be determined based on one or more detected phase and / or amplitude variations, overlay and / or alignment values ​​indicated by measurement signals, and / or other similar systems and / or other information. These one or more parameters may include radiation parameters (radiation used for measurement), overlay values, alignment values, measurement inspection locations on layers of the semiconductor device structure, radiation beam trajectories through the target, and / or other parameters. In some embodiments, process parameters may be broadly interpreted to include stage location, 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.

[0118] In some embodiments, operation 1506 includes determining process adjustments based on one or more determined semiconductor device manufacturing process parameters, adjusting the semiconductor device manufacturing apparatus based on the determined adjustments, and / or other operations. 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 whose process parameters have drifted and / or otherwise changed, causing the process to no longer produce acceptable devices (e.g., the measurement may violate an acceptability 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 devices again.

[0119] For example, new or adjusted process parameters may cause previously unacceptable measurements to be adjusted back to acceptable ranges. New or adjusted process parameters can be compared to existing parameters for a given process. For example, if a difference exists, this difference can be used to determine adjustments to the apparatus used to generate the equipment (e.g., parameter "x" should be increased / decreased / changed to match a new or adjusted version of parameter "x" determined as part of operation 1506). In some embodiments, operation 1506 may include electronically adjusting the equipment (e.g., based on the determined process parameters). Electronically adjusting the equipment may include, for example, sending electronic signals and / or other communications to the equipment, causing changes to the equipment. Electronic adjustment may include, for example, changing settings and / or other adjustments on the equipment.

[0120] Figure 16 This is a diagram of an example computer system CS that can be used in 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 coupled to the bus BS for processing information (or...). Figure 3 The processor PRO shown may be similar to or the same as multiple processors. 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 other static storage devices coupled to the bus BS for storing static information and instructions for the processor PRO. Storage devices such as disks or optical discs SD are provided and coupled to the bus BS for storing information and instructions.

[0121] A computer system (CS) can be connected to a display (DS), such as a flat panel or touch panel monitor or a cathode ray tube (CRT), via a bus (BS) to display information to the computer user. Input device IDs (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 control (CC), such as a mouse, trackball, or arrow keys, which transmits directional information and command selections to the processor (PRO) and controls cursor movement on the display (DS). This type of input device typically has two degrees of freedom on two axes (e.g., a first axis (x) and a second axis (y)), allowing the device to specify its position in a plane. Touch panel (screen) displays can also be used as input devices.

[0122] In some embodiments, one or more operations described herein can be performed 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 instruction sequence included in main memory MM causes processor PRO to perform the processing steps (operations) described herein. One or more processors in a multiprocessor arrangement may also be used to execute the instruction sequence 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.

[0123] As used herein, the term "computer-readable medium" or "machine-readable medium" refers to any medium that participates in providing instructions to a processor (PRO) for execution. Such media can take many forms, including but not limited to non-volatile media, volatile media, and transmission media. For example, non-volatile media include 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 wires forming 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 communication. Computer-readable media can be non-transitory, such as floppy disks, flexible disks, hard disks, magnetic tape, any other magnetic media, CD-ROMs, DVDs, any other optical media, punched cards, paper tape, any other physical media with an aperture pattern, RAM, PROMs and EPROMs, FLASH-EPROMs, any other memory chips or cartridges. Instructions may be recorded on a non-transitory computer-readable medium. When executed by a computer, these instructions can perform any of the operations described herein. For example, transient computer-readable media may include carrier waves or other propagating electromagnetic signals.

[0124] Various forms of computer-readable media can involve carrying one or more sequences of instructions to a processor PRO for execution. For example, instructions may initially be stored 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 may 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 may receive the data carried in the infrared signal and place the data on the bus BS. The bus BS carries the data to main memory MM, from which the processor PRO retrieves and executes the instructions. 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.

[0125] The computer system CS may also include a communication interface CI coupled to the bus BS. The communication interface CI provides bidirectional data communication coupled to a network link NDL connected to a 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 Local Area Network (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 carrying digital data streams representing various types of information.

[0126] 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 from a local area network (LAN) to a host computer (HC). This can include data communication services provided through global packet data communication networks, now commonly referred to as the "Internet" (INT). A LAN (Internet) can use electrical, electromagnetic, or optical signals to carry digital data streams. Signals through various networks, as well as signals on the network data link (NDL) and signals through the communication interface (CI), are example forms of carrier waves that transmit digital data to and from a computer system (CS).

[0127] Computer system CS can send and receive messages, including program code, via one or more networks, network data links (NDLs), and communication interfaces (CIs). In the Internet example, host computer HC can send application request codes via Internet (INT), network data links (NDLs), local area networks (LANs), and communication interfaces (CIs). For example, a downloading application could provide all or part of the methods described herein. Received code can be executed by processor PRO upon receipt and / or stored in storage devices (SDs) or other non-volatile storage devices for later execution. In this way, computer system CS can obtain application code in carrier form.

[0128] Various embodiments of the system and method are disclosed in the subsequent list of numbered clauses. Further features, characteristics, and exemplary technical solutions of this disclosure will be described below in accordance with clauses that may optionally be claimed in any combination: 1. A measurement system comprising: a radiation source configured to radiate a measurement target in one or more layers of a patterned substrate, the measurement target being configured to diffract the radiation from the radiation source and impart orbital angular momentum to the radiation; and a radiation sensor configured to generate a measurement signal based on the orbital angular momentum of the diffracted radiation received from the measurement target, the measurement signal including alignment position information and / or overlay information of the one or more layers. 2. The system according to Clause 1, wherein the radiation from the radiation source comprises a Gaussian radiation beam or a vortex radiation beam. 3. The system according to any one of the preceding clauses, wherein the radiation from the radiation source is diffracted and imparts orbital angular momentum to the radiation from the radiation source to form a diffracted radiation beam having non-zero orbital angular momentum and / or having optical vortices. 4. The system according to any one of the preceding clauses further includes a vortex separator configured to separate the diffracted radiation having the orbital angular momentum into even-numbered orbital angular momentum components and odd-numbered orbital angular momentum components. 5. The system according to any one of the preceding clauses, wherein the radiation sensor comprises: a first sensor configured to detect even-numbered orbital angular momentum components of diffracted radiation having orbital angular momentum; and a second sensor configured to detect odd-numbered orbital angular momentum components. 6. The system according to any one of the preceding clauses, wherein the first sensor and the second sensor comprise a first single-pixel photodetector and a second single-pixel photodetector, or a first camera and a second camera. 7. The system according to any one of the preceding clauses, wherein the first sensor and the second sensor comprise a first interferometer and a second interferometer. 8. The system according to any one of the preceding clauses further includes the measurement target, the measurement target being configured to generate a singularity in the phase of the diffraction beam, the measurement target comprising a grating having a fork shape or a vernier scale appearance. 9. The system according to any one of the preceding clauses, wherein the measurement target comprises: a first grating in a first portion of a layer of the patterned substrate and a second grating in a second adjacent portion of the layer of the patterned substrate; or a first grating in a first layer of one or more layers of the patterned substrate and a second grating in a second layer of one or more layers of the patterned substrate, wherein the first grating and the second grating together form a grating having a fork-shaped or vernier scale appearance. 10. The system according to any one of the preceding clauses, wherein the measurement target comprises: a target shape configured to generate a singularity in the phase of a diffraction beam in a single layer of the patterned substrate; or a first target shape in a first layer of one or more layers of the patterned substrate and a second target shape in a second layer of one or more layers of the patterned substrate, the second target shape being rotated approximately 90 degrees relative to the first target shape. 11. The system according to any one of the preceding clauses, wherein the measurement signal is an alignment signal or an overlay signal. 12. The system according to any one of the preceding clauses, wherein the radiation sensor is further configured to detect the phase, intensity, wavelength and / or polarization of diffracted radiation received from the measurement target, as well as the orbital angular momentum, and to generate the measurement signal based on the orbital angular momentum and the phase, intensity, wavelength and / or polarization. 13. The system according to any one of the preceding clauses further includes one or more processors configured to determine the alignment and / or overlay of the one or more layers based on the measurement signal. 14. The system according to any of the preceding clauses, wherein the one or more processors are further configured to filter and separate the diagonal and off-diagonal orders of the diffracted radiation from the measurement target having the orbital angular momentum, the diagonal order having an even number of optical vortices and the off-diagonal order having an odd number of optical vortices, or vice versa. 15. The system according to any one of the preceding clauses, wherein the one or more processors are configured to filter and decouple to avoid crosstalk. 16. The system according to any one of the preceding clauses, wherein the measurement target configured to diffract the radiation from the radiation source and impart the orbital angular momentum to the radiation from the radiation source is different from structures in one or more layers that are adjacent to, close to and / or surrounding the measurement target and cannot generate diffracted vortex beams. 17. The system according to any one of the preceding clauses, wherein the alignment position information and / or overlay information of said one or more layers includes an indication of the shape change of the diffracted radiation vortex beam in the measurement signal. 18. The system according to any one of the preceding clauses further includes one or more beam splitters, prisms, mirrors and / or lenses configured to receive the diffracted radiation having the orbital angular momentum from the measurement target and to direct the received diffracted radiation having the orbital angular momentum toward the radiation sensor. 19. The system according to any one of the preceding clauses, wherein the one or more beam splitters, prisms, mirrors and / or lenses form a first path of even-numbered orbital angular momentum components and a second path of odd-numbered orbital angular momentum components of the diffracted radiation having the orbital angular momentum. 20. The system according to any one of the preceding clauses, wherein the measurement signal is configured to be used by one or more processors to regulate a semiconductor device manufacturing process. 21. A measurement method comprising: irradiating a measurement target in one or more layers of a patterned substrate with radiation from a radiation source, the measurement target being configured to diffract the radiation from the radiation source and impart orbital angular momentum to the radiation; and generating a measurement signal using a radiation sensor based on the orbital angular momentum of the diffracted radiation received from the measurement target, the measurement signal including alignment position information and / or overlay information of the one or more layers. 22. The method according to Clause 21, wherein the radiation from the radiation source comprises a Gaussian radiation beam or a vortex radiation beam. 23. The method according to any one of the preceding clauses, wherein the radiation from the radiation source is diffracted and the orbital angular momentum is imparted to form a diffracted radiation beam having non-zero orbital angular momentum and / or having optical vortices. 24. The method according to any one of the preceding clauses further includes using a vortex separator to separate the diffracted radiation having orbital angular momentum into even-numbered orbital angular momentum components and odd-numbered orbital angular momentum components. 25. The method according to any one of the preceding clauses, wherein the radiation sensor comprises: a first sensor configured to detect even-numbered orbital angular momentum components of the diffracted radiation having orbital angular momentum, and a second sensor configured to detect odd-numbered orbital angular momentum components. 26. The method according to any one of the preceding clauses, wherein the first sensor and the second sensor comprise a first single-pixel photodetector and a second single-pixel photodetector, or a first camera and a second camera. 27. The method according to any one of the preceding clauses, wherein the first sensor and the second sensor comprise a first interferometer and a second interferometer. 28. The method according to any one of the preceding clauses further includes generating a singularity in the phase of the diffraction beam using the measurement target, the measurement target comprising a grating having a fork shape or a vernier-scale appearance. 29. The method according to any one of the preceding clauses, wherein the measurement target comprises: a first grating in a first portion of a layer of the patterned substrate and a second grating in a second adjacent portion of the layer of the patterned substrate; or a first grating in a first layer of one or more layers of the patterned substrate and a second grating in a second layer of one or more layers of the patterned substrate, wherein the first grating and the second grating together form a grating having a fork-shaped or vernier scale appearance. 30. The method according to any one of the preceding clauses, wherein the measurement target comprises: a target shape configured to generate a singularity in the phase of a diffraction beam in a single layer of the patterned substrate; or a first target shape in a first layer of one or more layers of the patterned substrate and a second target shape in a second layer of one or more layers of the patterned substrate, the second target shape being rotated approximately 90 degrees relative to the first target shape. 31. The method according to any one of the preceding clauses, wherein the measurement signal is an alignment signal or an overlay signal. 32. The method according to any one of the preceding clauses further includes using the radiation sensor to detect the phase, intensity, wavelength and / or polarization of diffracted radiation received from the measurement target, as well as the orbital angular momentum, and generating the measurement signal based on the orbital angular momentum and the phase, intensity, wavelength and / or polarization. 33. The method according to any one of the preceding clauses further includes using one or more processors to determine the alignment and / or overlay of the one or more layers based on the measurement signal. 34. The method according to any one of the preceding clauses, wherein the one or more processors are further configured to filter and separate the diagonal and off-diagonal orders of the diffracted radiation from the measurement target having the orbital angular momentum, the diagonal order having an even number of optical vortices and the off-diagonal order having an odd number of optical vortices, or vice versa. 35. The method according to any one of the preceding clauses, wherein the one or more processors are configured to filter and separate to avoid crosstalk. 36. The method according to any one of the preceding clauses, wherein the measurement target configured to diffract the radiation from the radiation source and impart the orbital angular momentum to the radiation from the radiation source is different from structures in one or more layers that are adjacent to, close to and / or surrounding the measurement target and cannot generate diffracted vortex beams. 37. The method according to any one of the preceding clauses, wherein the alignment position information and / or overlay information of the one or more layers includes an indication of the shape change of the diffracted radiation vortex beam in the measurement signal. 38. The method according to any one of the preceding clauses further comprises receiving diffracted radiation with orbital angular momentum from the measurement target using one or more beam splitters, prisms, mirrors and / or lenses, and directing the received diffracted radiation with orbital angular momentum toward the radiation sensor. 39. The method according to any one of the preceding clauses, wherein the one or more beam splitters, prisms, mirrors and / or lenses form a first path of even-numbered orbital angular momentum components and a second path of odd-numbered orbital angular momentum components of diffracted radiation having orbital angular momentum. 40. The method according to any one of the preceding clauses, wherein the measurement signal is configured to be used by one or more processors to regulate a semiconductor device manufacturing process.

[0129] The concepts disclosed herein can be associated with any general imaging system used for imaging sub-wavelength features, and are particularly applicable to emerging imaging techniques capable of generating increasingly shorter wavelengths. Emerging techniques already in use include EUV (Extreme Ultraviolet) and DUV lithography, with DUV lithography capable of generating 193 nm wavelengths using ArF lasers and even 157 nm wavelengths using fluorine lasers. Furthermore, EUV lithography can generate wavelengths in the 20–5 nm range by using synchrotrons or by bombarding materials (solid-state or plasma) with high-energy electrons, thereby generating photons within this range.

[0130] 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 with any type of lithography imaging system (e.g., a lithography imaging system for imaging on substrates other than silicon wafers). Furthermore, combinations and sub-combinations of the disclosed elements can include individual embodiments.

[0131] The above description is intended to illustrate and not limit. Therefore, it will be apparent to those skilled in the art that modifications as described can be made without departing from the scope of the claims set forth below.

Claims

1. A measurement system, comprising: A radiation source is configured to radiate a measurement target in one or more layers of a patterned substrate with radiation, the measurement target being configured to diffract the radiation from the radiation source and impart orbital angular momentum to the radiation; as well as A radiation sensor is configured to generate a measurement signal based on the orbital angular momentum of the diffracted radiation received from the measurement target, the measurement signal including alignment position information and / or overlay information of the one or more layers.

2. The system of claim 1, wherein the radiation from the radiation source comprises a Gaussian radiation beam or a vortex radiation beam.

3. The system according to claim 1 or 2, wherein the radiation from the radiation source is diffracted and imparts orbital angular momentum to the radiation from the radiation source to form a diffracted radiation beam having non-zero orbital angular momentum and / or having optical vortices.

4. The system according to any one of claims 1-3, further comprising a vortex separator configured to separate the diffracted radiation having the orbital angular momentum into even-numbered orbital angular momentum components and odd-numbered orbital angular momentum components.

5. The system according to any one of claims 1-4, wherein the radiation sensor comprises: The first sensor is configured to detect even-numbered orbital angular momentum components, and The second sensor is configured to detect the odd-numbered orbital angular momentum components of the diffracted radiation having the orbital angular momentum.

6. The system of claim 5, wherein the first sensor and the second sensor comprise a first single-pixel photodetector and a second single-pixel photodetector, or a first camera and a second camera.

7. The system according to claim 5, wherein the first sensor and the second sensor comprise a first interferometer and a second interferometer.

8. The system according to any one of claims 1-7, further comprising the measurement target configured to generate a singularity in the phase of the diffracted beam, the measurement target comprising a grating having a fork shape or a vernier scale appearance.

9. The system of claim 8, wherein the measurement target comprises: A first grating in a first portion of a layer on the patterned substrate and a second grating in a second adjacent portion of the layer on the patterned substrate; or A first grating in a first layer of one or more layers of the patterned substrate and a second grating in a second layer of one or more layers of the patterned substrate, The first grating and the second grating together form the grating having the appearance of the fork or vernier scale.

10. The system according to any one of claims 1-9, wherein the measurement target comprises: The target shape is configured to generate a singularity in the phase of the diffraction beam in a single layer of the patterned substrate; or The patterned substrate has a first target shape in a first layer of one or more layers and a second target shape in a second layer of one or more layers, the second target shape being rotated approximately 90 degrees relative to the first target shape.

11. The system according to any one of claims 1-10, wherein the measurement signal is an alignment signal or an overlay signal.

12. The system according to any one of claims 1-11, wherein the radiation sensor is further configured to detect the phase, intensity, wavelength and / or polarization of the diffracted radiation received from the measurement target, as well as the orbital angular momentum, and to generate the measurement signal based on the orbital angular momentum and the phase, intensity, wavelength and / or polarization.

13. The system according to any one of claims 1-12, further comprising one or more processors configured to determine the alignment and / or overlay of the one or more layers based on the measurement signal.

14. The system of claim 13, wherein the one or more processors are further configured to filter and separate the diagonal and off-diagonal orders of the diffracted radiation with orbital angular momentum from the measurement target, the diagonal order having an even number of optical vortices and the off-diagonal order having an odd number of optical vortices, or vice versa.

15. The system of claim 14, wherein the one or more processors are configured to filter and separate to avoid crosstalk.

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