Multi-core waveguide for semiconductor metrology systems and methods

Abstract

Multi-core waveguides, such as optical fibers, for semiconductor metrology systems and methods are described. The multi-core waveguide is configured to conduct radiation from the radiation source to a structure in one or more layers of the patterned substrate, such as a metrology target, and to conduct diffracted and / or reflected radiation from the metrology target to the radiation sensor. The length of the multi-core waveguide is configured to facilitate placement of radiation sources and / or radiation sensors relative to the patterned substrate in spaced apart positions. The length of the multi-core waveguide is configured to provide increased functional space for other components of the metrology system (e.g., various lenses and / or other optical components) located near the patterned substrate.

Description

Cross-references to related applications

[0001] This application claims priority to U.S. Application 63 / 543,762, filed October 12, 2023, which is incorporated herein by reference in its entirety. Technical Field

[0002] This specification relates to multicore waveguides for use in semiconductor measurement systems and methods. Background Technology

[0003] Photolithography projection apparatuses can be used, for example, in the fabrication of integrated circuits (ICs). Patterning apparatuses (e.g., masks) can include or provide a pattern corresponding to a single layer (“design layout”) of the IC, and this pattern can be transferred to a target portion (e.g., comprising one or more dies) of a substrate (e.g., a silicon wafer) coated with a radiation-sensitive material layer (“resist”) by methods such as radiating the pattern onto the target portion of the pattern on the patterning apparatus. Typically, a single substrate comprises multiple adjacent target portions, and the pattern is sequentially transferred to these target portions one by one by the photolithography projection apparatus. In one type of photolithography projection apparatus, a pattern across the entire patterning apparatus is transferred to a single target portion in one operation. Such apparatuses are commonly referred to as steppers. In alternative apparatuses (commonly referred to as step-scan apparatuses), a projection beam scans the patterning apparatus in a given reference direction (“scan” direction) while simultaneously moving the substrate parallel or antiparallel to that reference direction. Different portions of the pattern on the patterning apparatus are progressively transferred to a single target portion.

[0004] Before a pattern is transferred from the patterning apparatus 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 a single layer of a device (e.g., an IC). The substrate can then undergo various processes, such as etching, ion implantation (doping), metallization, oxidation, deposition, chemical mechanical polishing, etc., designed to complete a single layer of the device. If the device requires multiple layers, the entire process or a variation thereof is repeated for each layer. Ultimately, the device will appear in each target portion of the substrate. These devices are then separated from each other using techniques such as dicing or sawing, allowing the individual devices to be mounted on a carrier, connected to pins, etc.

[0005] This device fabrication process can be considered a patterning process. A patterning process involves patterning steps, such as optical and / or nanoimprint lithography using a patterning apparatus in a photolithography unit, to transfer a pattern from the patterning apparatus to a substrate, 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 with the pattern using an etching apparatus, deposition, etc. Photolithography is a central step in the fabrication of devices such as ICs, where the pattern formed on the substrate defines the functional elements of the device, such as microprocessors, memory chips, etc. Similar photolithography techniques are also used to form flat panel displays, microelectromechanical systems (MEMS), and other devices.

[0006] 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 steadily increased over the past few decades, following a trend commonly known as "Moore's Law." In the current state of technology, device layers are fabricated using photolithography projection devices that project a design layout onto a substrate using a deep ultraviolet irradiation source, thereby creating individual functional components with dimensions well below 100 nm (i.e., less than half the wavelength of radiation from an irradiation source, such as a 193 nm irradiation source).

[0007] This process of printing features at sizes smaller than the classical resolution limit of a photolithography projection apparatus, according to the resolution formula CD = k1 × λ / NA, is often referred to as low-k1 lithography, where λ is the wavelength of the radiation used (currently mostly 248 nm or 193 nm), NA is the numerical aperture of the projection optics in the photolithography projection apparatus, CD is the "critical size"—typically the smallest printed feature size—and k1 is an empirical resolution factor. Generally, the smaller k1 is, the more difficult it is to reproduce on the substrate a pattern with a shape and size similar to what the designer planned for specific electrical functions and performance. To overcome these difficulties, complex fine-tuning steps are applied to the photolithography projection apparatus, design layout, or patterning apparatus. These include, but are not limited to: optimizing NA and optical coherence settings, customizing illumination schemes, using phase-shifting 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). Measurement is an integral part of these fine-tuning steps. Summary of the Invention

[0008] Multi-core waveguides, such as optical fibers, are described for semiconductor measurement systems and methods. The multi-core waveguides are configured to conduct radiation from a radiation source to a structure (such as a measurement target) in one or more layers of a patterned substrate, and to conduct the diffracted and / or reflected radiation from the measurement target to a radiation sensor. The length of the multi-core waveguides is configured to facilitate the placement of the radiation source and / or the radiation sensor relative to the patterned substrate at spaced-apart locations. The length of the multi-core waveguides is configured to provide increased functional space for other components of the measurement system located near the patterned substrate, such as various lenses and / or other optical components.

[0009] According to one embodiment, a semiconductor measurement system is provided. The system includes: a radiation source configured to radiate a structure in one or more layers of a patterned substrate. The system includes: a radiation sensor configured to generate a measurement signal based on diffracted and / or reflected radiation received from the structure. The measurement signal includes measurement information for the one or more layers. The system includes: one or more multi-core waveguides configured to conduct radiation from the radiation source to the structure and to conduct the diffracted and / or reflected radiation from the structure to the radiation sensor. The lengths of the one or more multi-core waveguides are configured to facilitate the placement of the radiation source and / or the radiation sensor relative to the patterned substrate at spaced-out locations.

[0010] In some embodiments, the system includes one or more substrate-side lenses configured to focus radiation from the radiation source onto the structure and to guide diffracted and / or reflected radiation from the structure into the one or more multi-core waveguides. The one or more substrate-side lenses may include a substrate-side microlens array. In some embodiments, the number of lenses in the substrate-side microlens array corresponds to the number of fiber cores in the one or more multi-core waveguides.

[0011] The lengths of the one or more multi-core waveguides are configured to facilitate the placement of the radiation source and / or the radiation sensor at spaced locations relative to the patterned substrate, thereby providing increased functional space for other components of the measurement system located near the patterned substrate. These other components include, for example, the substrate-side microlens array.

[0012] In some embodiments, the system includes one or more source- and sensor-side lenses configured to direct radiation from the radiation source into the one or more multi-core waveguides and to direct diffracted and / or reflected radiation from the substrate, conducted through the one or more multi-core waveguides, toward the radiation sensor. The one or more source- and sensor-side lenses may include source- and sensor-side microlens arrays. The number of lenses in the source- and sensor-side microlens arrays may correspond to the number of fiber cores in the one or more multi-core waveguides.

[0013] In some embodiments, the spaced-out locations include locations away from the patterned substrate on one side including the structure and the one or more layers. In some embodiments, the length of the one or more multi-core waveguides is up to about 0.1 m, 0.25 m, 0.5 m, 1 m, or 10 m.

[0014] In some embodiments, the radiation source is configured to generate spatially incoherent and / or partially coherent radiation, and the radiation from the radiation source comprises multiple modes. In some embodiments, the number of the multiple modes corresponds to the number of cores in the one or more multi-core waveguides. In some embodiments, the number of cores is the total number of cores. In some embodiments, when the one or more multi-core waveguides are located at a Fourier and / or pupil plane with respect to the patterned substrate, the number of cores is a subset of the total number of cores.

[0015] In some embodiments, each core in the one or more multi-core waveguides conducts radiation in a single spatial mode. In some embodiments, the radiation in the single spatial mode covers a wavelength range of 450 to 900 nm, 450 to 1100 nm, and / or 450 to 1800 nm. Each core may, for example, resemble an infinite single-mode photonic crystal fiber.

[0016] In some embodiments, each core of the one or more multi-core waveguides is configured to support 2 to 10 spatial modes in at least a portion of a given wavelength range. In some embodiments, each core of the one or more multi-core waveguides is polarization-preserving, such that each core supports only one spatial mode with a unique polarization, or supports two spatial modes with orthogonal polarizations and these two modes do not mix, wherein the two modes have the same or similar spatial mode distributions. In some embodiments, each core of the one or more multi-core waveguides is non-polarization-preserving, such that each core of the one or more multi-core waveguides supports two modes, the two modes having at least approximately the same spatial mode distribution but with orthogonal polarizations.

[0017] In some embodiments, the radiation in the different cores of the one or more multi-core waveguides is spatially incoherent with respect to each other.

[0018] In some embodiments, the radiation source is configured to generate spatially coherent radiation.

[0019] In some embodiments, radiation from the radiation source in one or more different cores of the one or more multi-core waveguides includes off-axis irradiation relative to the structure in the patterned substrate.

[0020] In some embodiments, a first core (or a subset of first cores) in one or more multi-core waveguides is configured to conduct +1st order diffraction radiation from the structure toward the sensor, and a second core in one or more multi-core waveguides is configured to conduct -1st order diffraction radiation from the structure toward the sensor.

[0021] In some embodiments, the radiation source and the one or more multi-core waveguides are configured such that a subset of the cores in the one or more multi-core waveguides are used to conduct the radiation from the radiation source to the structure, and such that the diffracted light from the structure is captured by different subsets of the cores.

[0022] In some embodiments, the system includes an optical element configured to block zero-order light from the patterned substrate with respect to first-order or higher-order diffracted light, or to separate the zero-order light onto different radiation sensors. The optical element may be located on the radiation sensor side of the one or more multi-core waveguides, or it may be located on the patterned substrate side of the one or more multi-core waveguides.

[0023] In some embodiments, the radiation source is configured such that the radiation includes at least pairwise spatial coherence between pairs of illumination patterns on opposite sides of the illumination pupil.

[0024] In some embodiments, the system includes one or more processors configured to determine alignment positions and / or overlaps for the one or more layers based on the measurement signals. The one or more processors may be configured to determine the alignment positions and / or overlaps by determining the phase difference between the +1 and -1 diffraction orders of the diffraction radiation from the structure.

[0025] In some embodiments, the structure includes measurement markers. In some embodiments, the structure includes diffraction-based overlapping measurement markers, the diffraction-based overlapping measurement markers including a first grating in a lower layer of the patterned substrate and a second grating in an upper layer of the patterned substrate. The second grating may be located directly above the first grating in the patterned substrate; and the measurement signal may be configured for use by one or more processors to adjust the semiconductor device manufacturing process.

[0026] In some embodiments, the measurement information includes optical measurement information. In some embodiments, the measurement information includes alignment position information, overlap information, focus measurement information, and / or exposure dose measurement information.

[0027] In some embodiments, the one or more multi-core waveguides include two or more multi-core waveguides per radiation sensor. The two or more multi-core waveguides per radiation sensor may include: a multi-core waveguide configured to deliver radiation to the structure, and a separate multi-core waveguide configured to conduct radiation for detection; and / or two or more multi-core waveguides for the detection, each having one multi-core waveguide for each polarization state diffracted by the structure.

[0028] In some embodiments, the one or more multi-core waveguides are configured to support different wavelength ranges.

[0029] In some embodiments, the system includes polarization selection and / or rotation optics located between the one or more multi-core waveguides and the structure.

[0030] In some embodiments, the one or more multi-core waveguides include one or more multi-core optical fibers.

[0031] In some embodiments, the one or more multi-core waveguides include super-directional etching in a crystalline material, optical ablation structures, structures formed by layer-by-layer deposition, and / or printed waveguides stacked in multiple layers on a substrate.

[0032] According to another embodiment, a semiconductor metrology system is provided. The system includes: a stage configured to hold and / or move a patterned substrate. The patterned substrate includes a measurement target structure in one or more layers of the patterned substrate. The system includes: a radiation sensor configured to generate an image based on diffracted radiation received from the target structure. The image includes measurement information for the one or more layers. The system includes: one or more conduits configured to conduct radiation from a radiation source to the target structure and to conduct the diffracted radiation from the target structure to the radiation sensor. The lengths of the one or more conduits are configured to facilitate positioning the radiation source and / or the radiation sensor relative to the patterned substrate at spaced-apart locations. The system includes: one or more actuators configured to synchronize the movement of the stage, the radiation sensor, and / or the one or more conduits to scan the measurement target structure. The radiation sensor is configured to generate the image based on diffracted radiation received during scanning.

[0033] In some embodiments, the scanning is continuous, such that the radiation sensor receives an uninterrupted stream of diffracted radiation, which is used to generate the image.

[0034] In some embodiments, the radiation sensor includes a camera and / or a scanning mirror.

[0035] In some embodiments, the radiation sensor includes a camera with a shield, and the shield remains open throughout the scan.

[0036] According to another embodiment, a measurement method is provided. The measurement method includes one or more operations performed by the aforementioned systems(s). Attached Figure Description

[0037] The above and other aspects and features will become apparent to those skilled in the art upon review of the following description of specific embodiments in conjunction with the accompanying drawings.

[0038] Figure 1 A photolithography apparatus according to an embodiment is schematically depicted.

[0039] Figure 2 An embodiment of a lithography unit or cluster according to an embodiment is schematically depicted.

[0040] Figure 3 An example inspection system according to an embodiment is schematically depicted.

[0041] Figure 4 An example measurement technique according to an embodiment is schematically depicted.

[0042] Figure 5 The diagram illustrates the relationship between the radiation spot and the measurement target of the inspection system according to an embodiment.

[0043] Figure 6 The illustration shows a measurement system utilizing one or more multi-core waveguides according to an embodiment.

[0044] Figure 7 The illustration shows end views of three different possible examples of a multi-core waveguide formed as a multi-core optical fiber according to an embodiment.

[0045] Figure 8 The illustration shows another example measurement system utilizing one or more multi-core waveguides according to an embodiment.

[0046] Figure 9 The illustration depicts radiation from a radiation source in one or more different cores (two cores in this example) of a multi-core waveguide according to an embodiment, including off-axis illumination relative to a structure in a patterned substrate.

[0047] Figure 10 The illustration shows a radiation sensor (such as...) based on an embodiment. Figure 8 The simulated sensor image generated by the + and -1st order diffraction radiation of the radiation sensor shown.

[0048] Figure 11 Examples of crosstalk that can occur between radiations in different fiber cores according to an embodiment are illustrated, as well as corrections for such crosstalk.

[0049] Figure 12 The illustration shows another example measurement system utilizing one or more multi-core waveguides according to an embodiment.

[0050] Figure 13 The illustration shows yet another example measurement system utilizing one or more multi-core waveguides according to an embodiment.

[0051] Figure 14 The illustration shows a measurement method using one or more multi-core waveguides according to an embodiment.

[0052] Figure 15 The illustration depicts a system according to an embodiment for moving a synchronization stage, a radiation sensor, and / or one or more conduits to scan and measure a target structure. In some embodiments, the radiation sensor includes a camera and a scanning mirror, and synchronizing the movement of the radiation sensor includes synchronizing the movement of the scanning mirror while the camera remains stationary.

[0053] Figure 16 The illustration shows the relationship according to an embodiment. Figure 15 The scan path associated with the movement of the stage and the target structure is shown.

[0054] Figure 17 The illustration shows one or more radiation sensors from the radiation sensors described herein in both non-scanning and scanning modes according to embodiments. Figure 15 Sample images obtained and / or otherwise generated during the scanning process.

[0055] Figure 18 An embodiment of the system is illustrated, which has a phase and / or amplitude mask located on the substrate side of one or more conduits in the system's Fourier plane.

[0056] Figure 19 This is a block diagram of an example computer system according to an embodiment. Detailed Implementation

[0057] In semiconductor device fabrication, metrology operations typically involve determining the location of measurement markers and / or other structures within one or more layers of a semiconductor device structure, such as a patterned substrate. 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 overlap, alignment, and / or other parameters.

[0058] This system and method utilize one or more multi-core waveguides configured to conduct radiation from a radiation source to measurement markers and / or other structures, and to conduct diffracted and / or reflected radiation back to a radiation sensor. The lengths of the one or more multi-core waveguides are configured to facilitate the placement of the radiation source, radiation sensor, actuator, processor, associated electronics, and / or other components of the measurement system at spaced locations relative to a patterned substrate. This provides increased functional space for other components of the measurement system located near the patterned substrate, which can reduce or eliminate some of the engineering constraints in a system configured to measure an increased number of markers, and / or offer other advantages.

[0059] For brevity, the following description relates to semiconductor device fabrication and patterning processes. The following paragraphs also describe some components of systems and / or methods used for semiconductor device metrology. These systems and methods can be used, for example, to measure overlap, alignment, focusing, dosing, etc., in semiconductor device fabrication processes, or for other operations.

[0060] While this specification may specifically refer to the manufacture of integrated circuits (ICs) for semiconductor devices, it should be understood that it has many other possible applications. For example, it can be used to manufacture integrated optical systems, guide and detection patterns for magnetic domain memories, liquid crystal display panels, 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.

[0061] The term "projection optics" should be interpreted broadly to encompass various types of optical systems, including refractive optics, reflective optics, aperture optics, and catadioptric optics. The term "projection optics" may also include components used, according to any of these design types, for commonly or individually guiding, shaping, or controlling a projected radiation beam. The term "projection optics" can include any optical component in a lithography projection apparatus, regardless of its location in the optical path of the apparatus. Projection optics can include optical components for shaping, modulating, and / or projecting radiation from a source before the radiation passes through the patterning apparatus, and / or for shaping, modulating, and / or projecting radiation after the radiation passes through the patterning apparatus. Projection optics typically do not include a source or patterning apparatus.

[0062] Figure 1 An embodiment of a photolithography apparatus LA is schematically depicted. The apparatus includes: an illumination system (illuminator) IL configured to modulate a radiation beam B (e.g., UV, DUV, or EUV radiation); a support structure (e.g., a mask stage) MT configured to support a patterning apparatus (e.g., a mask) MA and connected to a first positioner PM configured to precisely position the patterning apparatus according to certain parameters; a substrate stage (e.g., a wafer stage) WT (e.g., WTa, WTb, or both) configured to hold a substrate (e.g., a resist-coated wafer) W and coupled to a second positioner PW configured to 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 apparatus MA onto a target portion C (e.g., comprising one or more dies, commonly referred to as a field) of the substrate W. The projection system is supported on a reference frame RF. In this example, the apparatus is transmissive (e.g., employing a transmissive mask). Alternatively, the apparatus may be reflective (e.g., employing a programmable mirror array or a reflective mask).

[0063] The irradiator IL receives a radiation beam from the radiation source SO. The source and the lithography apparatus can be separate entities, such as when the source is an excimer laser. In this case, the source is not considered part of forming the lithography apparatus, and the radiation beam is delivered from the source SO to the irradiator IL via a beam delivery system BD that includes, for example, suitable directional mirrors and / or beam expanders. In other cases, the source can be part of the apparatus, such as when the source is a mercury lamp. The source SO and the irradiator IL, together with the beam delivery system BD (if necessary), can be collectively referred to as the radiation system or the source.

[0064] 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 is non-zero within an annular region of the pupil plane of the illuminator IL. Additionally or alternatively, the illuminator IL can be operated to limit the beam distribution within the pupil plane such that the intensity distribution is non-zero in multiple equally spaced sectors within the pupil plane. The intensity distribution of the radiation beam within the pupil plane of the illuminator IL can be referred to as the illumination mode.

[0065] An illuminator IL may include a modulator AD configured to adjust the (angular / spatial) intensity distribution of the beam. Typically, the outer and / or inner radial ranges of the intensity distribution in the pupil plane of the illuminator (often referred to as σ-outer and σ-inner, respectively) can be adjusted. The illuminator IL can be operated to change the angular distribution of the beam. For example, the illuminator can be operated to change the number and angular range of sectors with non-zero intensity distribution in the pupil plane. Different illumination modes can be achieved by adjusting the intensity distribution 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, for example, a dipole, tetrapole, or hexapole distribution. The desired illumination mode can be obtained, for example, by inserting an optics providing this illumination mode into the illuminator IL or by using a spatial light modulator.

[0066] The illuminator IL is operable to change the polarization of the beam and can be operated to adjust the polarization using the modulator AD. The polarization state of the radiation beam across the pupil plane of the illuminator IL can be called the polarization mode. Using different polarization modes can allow for greater contrast in the image formed on the substrate W. The radiation beam can be unpolarized. Alternatively, the illuminator can be arranged to linearly polarize the radiation beam. The polarization direction of the radiation beam can vary across the pupil plane of the illuminator IL. The polarization state 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 illumination mode. For a multi-pole illumination mode, the polarization of each pole of the radiation beam can generally be perpendicular to the position vector of that pole in the pupil plane of the illuminator IL. For example, for a dipole illumination mode, 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 the X-polarization state and the Y-polarization state. For a quadrupole 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 XY polarization. Similarly, for 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 that sector. This polarization mode can be called TE polarization.

[0067] 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, such as refractive, reflective, magnetic, electromagnetic, electrostatic, or other types of optical components, or any combination thereof, for guiding, shaping, or controlling radiation. Therefore, the irradiator provides a regulated radiation beam B with desired uniformity and intensity distribution across its cross-section.

[0068] A support structure (MT) supports the patterning apparatus in a manner dependent on the orientation of the patterning apparatus, the design of the lithography apparatus, and other conditions, such as whether the patterning apparatus is maintained in a vacuum environment. The support structure can use mechanical, vacuum, electrostatic, or other clamping techniques to hold the patterning apparatus. The support structure can be a frame or a stage, and can be fixed or movable as needed. The support structure ensures that the patterning apparatus is in the desired position, such as with a projection system. Any use of the terms "mask" or "mask" herein may be considered synonymous with the more general term "patterning apparatus".

[0069] As used herein, the term "patterning apparatus" should be broadly interpreted to refer to any apparatus that can be used to impart a pattern to a target portion of a substrate. In embodiments, a patterning apparatus is any apparatus that can be used to impart a pattern to the cross-section of a radiation beam to generate a pattern in the target portion of the substrate. It should be noted that the pattern imparted to the radiation beam may not perfectly correspond to the desired pattern in the target portion of the substrate, for example, if the pattern includes phase-shifting features or so-called auxiliary features. Typically, the pattern imparted to the radiation beam will correspond to a specific functional layer in the device, such as an integrated circuit, created in the target portion of the device.

[0070] Pattern forming apparatuses can be transmissive or reflective. Examples of pattern forming apparatuses 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, as well as various hybrid mask types. Examples of programmable mirror arrays employ a matrix arrangement of small mirrors, where each small mirror can be individually tilted to reflect the incident radiation beam in different directions. The tilted mirrors impart a pattern to the radiation beam reflected by the mirror matrix.

[0071] The term “projection system” should be interpreted broadly to encompass any type of projection system, including refractive, reflective, catadioptric, magnetic, electromagnetic, and electrostatic optical systems, or any combination thereof, adapted to the exposure radiation used, or other factors such as the use of immersion liquids or vacuum. Any use of the term “projection lens” herein may be considered synonymous with the more general term “projection system.”

[0072] 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 aberrations (phase changes across the pupil plane throughout the field). To achieve this, the adjustment mechanism may operate to manipulate one or more optical (e.g., lens) elements within the projection system PS in one or more different ways. The projection system may have a coordinate system in which its optical axis extends along the z-direction. The adjustment mechanism may operate to perform any combination of the following: displace one or more optical elements; tilt one or more optical elements; and / or deform 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 typically deviates from a plane perpendicular to the optical axis by rotation about axes in the x and / or y directions, although rotation about the z-axis may 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., freeform aspherical surfaces). Deformation of the optical elements may 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 across the pupil plane). The transmission map of the projection system PS can be used when designing a patterning apparatus (e.g., a mask) MA for a lithography apparatus LA. Using computational lithography, the patterning apparatus MA can be designed to at least partially correct apodization.

[0073] Photolithography apparatuses can have two (dual) or more stages (e.g., two or more substrate stages WTa, WTb, two or more patterning apparatus stages, substrate stage WTa and a stage WTb without a substrate below the projection system, WTb being dedicated to, for example, facilitating measurement and / or cleaning). In such "multi-stage" machines, additional stages can be used in parallel, or preparation steps can be performed on one or more stages while one or more other stages are being used for exposure. For example, alignment measurements can be performed using an alignment sensor AS, and / or level (height, tilt, etc.) measurements can be performed using a level sensor LS.

[0074] The photolithography apparatus can also be configured such that 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 structures such as the substrate must be submerged in the liquid, but only that the liquid is located between the projection system and the substrate during exposure.

[0075] In operation, the radiation beam is regulated and provided by the 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 the target portion C of the substrate W. The substrate stage WT can be precisely moved, for example, to position different target portions C in the path of the radiation beam B, by means of a second positioner PW and a position sensor IF (e.g., an interferometric device, a linear encoder, a 2D encoder, or a capacitive sensor). Similarly, the first positioner PM and another position sensor (in... Figure 1 (Not explicitly depicted) can be used to precisely position the pattern forming apparatus MA with respect to the path of the radiation beam B, for example, after mechanical retrieval from the mask library or during scanning. Typically, movement of the support structure MT can be achieved using long-stroke modules (coarse positioning) and short-stroke modules (fine positioning), which form part of the first positioner PM. Similarly, movement of the substrate stage WT can be achieved using long-stroke modules and short-stroke modules, which form 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 pattern forming apparatus MA and the substrate W can be aligned using pattern forming apparatus alignment marks M1, M2 and substrate alignment marks P1, P2. Although the illustrated substrate alignment marks occupy dedicated target portions, they can be located in the space between the target portions (these are called scribing alignment marks). Similarly, if more than one die is provided on the pattern forming apparatus MA, the pattern forming apparatus alignment marks can be located between the dies.

[0076] The lithography apparatus LA can be used in either stepping or scanning modes. In stepping mode, the support structure MT and substrate stage WT remain substantially stationary, and a pattern with an applied radiation beam is projected onto the target portion C in a single pass (i.e., a single static exposure). The substrate stage WT is then moved in the X and / or Y directions to expose different target portions C. In stepping mode, the maximum size of the exposure field limits the size of the target portion C imaged in a single static exposure. In scanning mode, the support structure MT and substrate stage WT are scanned synchronously, and a pattern with an applied radiation beam is projected onto the target portion C (i.e., a single dynamic exposure). The velocity and direction of the substrate stage WT relative to the support structure MT can be determined by the (reduced) magnification and image inversion characteristics of the projection system PS. In scanning mode, the maximum size of the exposure field limits the width of the target portion in a single dynamic exposure (in the non-scanning direction), while the length of the scanning motion determines the height of the target portion (in the scanning direction). In another mode, the support structure MT remains substantially stationary, holding the programmable patterning apparatus in place, and the substrate stage WT is moved or scanned, while a pattern with an applied radiation beam is projected onto the target portion C. In this mode, a pulsed radiation source is typically used, and the programmable patterning apparatus is updated as needed after each movement of the substrate stage WT or between consecutive radiation pulses during scanning. This operating mode can be readily applied to maskless lithography utilizing programmable patterning apparatuses, such as programmable mirror arrays of the type mentioned above. Combinations and / or variations of the above usage modes, or entirely different usage modes, can also be employed.

[0077] The substrate can be processed in a track (a tool typically used to apply a resist layer to the substrate and develop the exposed resist) or in a measurement or inspection tool before or after exposure. Furthermore, the substrate can be processed more than once, 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.

[0078] The terms “radiation” and “beam” used in this article for lithography cover all types of electromagnetic radiation, including ultraviolet (UV) or deep ultraviolet (DUV) radiation (e.g., 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.

[0079] Various patterns provided by or on a patterning apparatus can have different process windows, i.e., a space of process variables beneath which the pattern will be generated according to specifications. Examples of pattern specifications related to potential system defects include checks for necking, line pullback, line thinning, CD, edge placement, overlap, resist top loss, resist undercut, and / or bridging. The process windows of patterns on the 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 of the individual patterns within the individual patterns. In other words, these individual patterns limit the process windows of the set of patterns.

[0080] 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 devices for performing pre- and post-exposure processing on substrates. Typically, these include one or more spin coaters SC to deposit one or more resist layers, one or more developers to develop the exposed resist, one or more cold plates CH, and / or one or more baking plates BK. A substrate processor or robot RO picks up one or more substrates from input / output ports I / O1, I / O2, moves them between different process units, and delivers them to the lithography apparatus's feed stage LB. These devices, generally referred to collectively as tracks, are controlled by a track control unit TCU, which in turn is controlled by a supervisory control system SCS, which in turn controls the lithography apparatus via the lithography control unit LACU. Therefore, different units can be operated to maximize throughput and processing efficiency.

[0081] To ensure that substrates exposed by photolithography are correctly and consistently exposed, 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 desirable to inspect the substrate or other object to measure or determine one or more properties, such as alignment, overlap (e.g., between structures in an overlapping layer, or between structures in the same layer that are individually provided to the same layer via, for example, a dual patterning process), line thickness, critical dimension (CD), focus offset, material properties, appropriate exposure dose, etc. Therefore, fabrication facilities in which photolithography units (LCs) are located typically also include a metrology system that measures some or all of the substrate W (which has been processed in the photolithography 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 )).

[0082] One or more measurement parameters may include, for example, alignment, overlap 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, focus or focus error of an optical lithography step, dose or dose error of an optical lithography step, optical aberration of an optical lithography step, etc. The measurement is typically performed against one or more dedicated measurement targets provided on the substrate. The measurement may be performed after development but before etching, after etching, after deposition, and / or at other times.

[0083] Various techniques exist for measuring structures formed in patterning processes, including the use of scanning electron microscopy, image-based measurement tools, and / or various specialized instruments. One rapid and non-invasive specialized measurement tool is one that directs a radiation beam onto a target on a substrate surface and measures the properties of the scattered (diffracted / reflected) beam. By evaluating one or more properties of the radiation scattered by the substrate, one or more properties of the substrate can be determined. Traditionally, this can be referred to as diffraction-based metrology. Applications of such diffraction-based metrology include measurements of overlap, alignment, etc. For example, overlap and / or alignment can be measured by comparing portions of the diffraction spectrum (e.g., comparing different diffraction orders in the diffraction spectrum of a periodic grating).

[0084] In device fabrication processes (such as patterning or photolithography), substrates or other objects can undergo various types of measurements during or after the process. Measurements can determine whether a particular substrate has defects, establish adjustments to the process and the equipment used in the process (e.g., aligning two layers on a substrate or aligning a patterning apparatus to the substrate), measure the performance of the process and equipment, or be used for other purposes. Examples of measurements include optical imaging (e.g., optical microscopy), non-imaging optical measurements (e.g., diffraction-based measurements, such as the ASML YieldStar metrology tool and the ASML SMASH metrology system), mechanical measurements (e.g., profilometry using probes, atomic force microscopy (AFM)), and / or non-optical imaging (e.g., scanning electron microscopy (SEM)).

[0085] Measurement results can be provided directly or indirectly to the Supervisory Control System (SCS). If an error is detected, adjustments can be made to the exposure of subsequent substrates (especially if inspection can be performed quickly enough so that one or more other substrates in the batch remain to be exposed) and / or to the subsequent exposure of already exposed substrates. Furthermore, already exposed substrates can be stripped and reworked to improve yield, or discarded to avoid further processing on known defective substrates. In cases where only some target portions of the substrate are defective, further exposure can be performed only on those target portions that meet specifications. Other manufacturing process adjustments are also anticipated.

[0086] Measurement systems can be used to determine one or more properties of a substrate structure, particularly how one or more properties vary between different substrate structures, or between different layers of the same substrate structure. Measurement systems can be integrated into a photolithography apparatus (LA) or a photolithography unit (LC), or they can be stand-alone devices.

[0087] To enable measurement, one or more targets and / or other structures are typically provided specifically on a substrate. Typically, the targets are specially designed and may include periodic structures. For example, a target on the substrate may include one or more one-dimensional 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, a target may include one or more two-dimensional 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. These bars, pillars, or vias may alternatively be etched into the substrate (e.g., etched into one or more layers on the substrate).

[0088] Figure 3 An example measurement (inspection) system 10 is depicted that can be used to detect overlap, alignment, and / or perform other measurement operations. It includes a radiation or illumination source 2 that projects or otherwise radiates radiation toward and / or onto a substrate W (e.g., which may typically include measurement markers). The redirected radiation is passed to a radiation sensor, such as a spectrometer detector 4 and / or other sensors, which measure the spectrum (intensity as a function of wavelength) of specularly reflected and / or diffracted radiation, for example... Figure 4 The graph on the left is shown. The sensor can generate measurement signals that transmit measurement data indicating the properties of reflected radiation. Based on this data, the structure or profile of the detection spectrum can be generated by one or more processors (PRO). Figure 4 (A general example is shown in the figure) or other operations are performed to rebuild.

[0089] and Figure 1 Similar to the LA lithography apparatus in lithography, it can provide one or more substrate stages ( Figure 4 (Not shown) to hold the substrate W during measurement operations. One or more substrate stages may be in form with Figure 1The substrate stages WT (WTa or WTb or both) are the same or similar. In the example where the inspection system 10 is integrated with the lithography apparatus, they can even be the same substrate stage. 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., a measurement mark) and bring it under the objective. Typically, many measurements are performed on the target portion of the structure at different locations across the substrate W. The substrate support can move in the X and Y directions to obtain different targets and in the Z direction to obtain the desired position of the target portion relative to the focal point of the optical system. It is convenient to describe and contemplate the operation as if the objective were brought to different positions relative to the substrate, while in practice, for example, the optical system can remain substantially stationary (typically in the X and Y directions, but possibly also in the Z direction) while the substrate moves. As long as the relative positions of the substrate and the optical system are correct, it is in principle irrelevant which one moves, or both move, or a combination of the following: a part of the optical system moves (e.g. in the Z and / or tilt directions) while the rest of the optical system remains stationary and the substrate moves (e.g. in the X and Y directions, but optionally in the Z and / or tilt directions).

[0090] For typical metrological measurements, the target 30 on the substrate W can be a one-dimensional grating, which is printed such that, after development, the stripe is formed of solid resist lines (e.g., which may be covered by a deposited layer) and / or other materials. Alternatively, the target 30 can be a two-dimensional grating, which is printed such that, after development, the grating is formed of solid resist pillars and / or other features in the resist.

[0091] Strips, pillars, vias, and / or other features may be etched into or on a substrate (e.g., into one or more layers on the substrate), deposited on the substrate, covered by a deposited layer, and / or have other properties. Target (part) 30 (e.g., stripes, pillars, vias, etc.) is sensitive to variations in the patterning process (e.g., optical aberrations, focus variations, dose variations, etc. in a photolithography projection apparatus, such as in a projection system), such that process variations manifest as variations in target 30. Therefore, measurement data from target 30 can be used to determine adjustments to one or more manufacturing processes within the manufacturing process, and / or as a basis for making actual adjustments.

[0092] For example, measurement data from target 30 can indicate the overlap of semiconductor device layers. 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 overlap, and to determine adjustments for semiconductor device manufacturing equipment based on the determined semiconductor device manufacturing process parameters. In some embodiments, this can include stage position adjustments, or it can include determining adjustments for mask design, measurement target design, semiconductor device design, radiation intensity, radiation incident angle, radiation wavelength, pupil size and / or shape, resist material, and / or other process parameters.

[0093] Figure 5 The illustration shows a plan view of a typical target (e.g., a measurement marker) 30, and Figure 4 The typical range of the radiation spot S in the system. Typically, to obtain a diffraction spectrum unaffected by surrounding structures, in this embodiment, the target 30 is a periodic structure (e.g., a grating) larger than the width (e.g., diameter) of the radiation spot S. The width of the spot S may be smaller than the width and length of the target. In other words, the target is "underfilled" by illumination, and the diffraction signal essentially contains no signal from product features or other external features of the target itself. The illumination arrangement can be configured, for example, to provide uniform intensity illumination on the back focal plane of the objective lens. Alternatively, illumination can be restricted to an on-axis or off-axis direction by, for example, including an aperture in the illumination path.

[0094] Figure 6 The diagram illustrates a measurement system 600 utilizing one or more multi-core waveguides 602. System 600 can be similar to the one described above. Figure 3 The system 600 is described as system 10 and / or the same thereas. In some embodiments, one or more components of system 600 may be similar to or the same as one or more components of system 10. In some embodiments, one or more components of system 600 may replace, be used together with, and / or otherwise enhance one or more components of system 10. System 600 includes a radiation source 604, a radiation sensor 606, and / or other components.

[0095] Radiation source 604 (e.g., similar to Figure 3 Source 2 and / or the same thereof) is configured to pattern structures in one or more layers of substrate 608 using radiation 610 (e.g., such as Figure 3 (Target 30 shown). Radiation can be used to obtain measurements from this structure and / or for other purposes. Radiation can include irradiation such as visible light and / or other radiation. The structure can include one or more measurement targets and / or markers formed in a substrate such as a semiconductor wafer, such as diffraction grating targets, and / or other structures.

[0096] In some embodiments, the structure includes a diffraction-based overlapping measurement marker comprising a first grating in a lower layer of a patterned substrate and a second grating in an upper layer of the patterned substrate. The second grating may, for example, be directly above the first grating in the patterned substrate. 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, or determined by the system (e.g., Figure 3 The system 10 and / or shown Figure 6 The system 600 shown is determined based on previous measurements and / or otherwise. 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 can be any radiation suitable for interferometric measurements.

[0097] In some embodiments, radiation source 604 is configured to generate spatially coherent radiation. In some embodiments, radiation source 604 is configured to generate spatially incoherent and / or partially coherent radiation.

[0098] Radiation sensor 606 (e.g., similar to Figure 3 The detector 4 shown (and / or the same) is configured to generate a measurement signal based on diffracted and / or reflected radiation received from the structure. The measurement signal includes measurement information for one or more layers. The measurement information may include, for example, optical measurement information and / or other information. In some embodiments, the measurement information includes alignment position information, overlap information, focus measurement information, exposure dose measurement information, and / or other information.

[0099] In some embodiments, the radiation sensor 606 is configured to generate a measurement signal based on reflected radiation detected from the diffraction grating target(s) as described above. For example, the measurement signal may be an overlap and / or alignment signal, and / or other measurement signals, including overlap and / or alignment measurement information. The measurement information (e.g., overlap value, alignment value, and / or other information) may be determined using interferometry principles and / or other principles.

[0100] One or more multi-core waveguides 602 are configured to conduct radiation 610 from a radiation source 604 to a structure and to conduct diffracted and / or reflected radiation 610 from the structure to a radiation sensor 606. The waveguides 602 are passive, without moving or electrically controlled components. The one or more multi-core waveguides 602 have a length (e.g., the length of the line forming the one or more multi-core waveguides 602 in this example) configured to facilitate the placement of the radiation source 604, radiation sensor 606, and / or other components at spaced-apart locations relative to the patterned substrate 608. The length of the one or more multi-core waveguides 602 is configured to facilitate the placement of the radiation source 604 and / or radiation sensor 606 (and / or other components) at spaced-apart locations relative to the patterned substrate 608, thereby providing increased functional space for other components of the measurement system 600 located near the patterned substrate 608. In embodiments using multiple multi-core waveguides, various optical elements can be used to guide light from or to a particular waveguide. These components may include unpolarized beam splitters, polarized beam splitters, dichroic mirrors, partial mirrors (e.g., mirrors with apertures and placed at 45 degrees to the beam propagation direction), combinations thereof, etc.

[0101] These components may include a substrate-side microlens array 620, such as a single lens and / or various other components. For example, on the wafer side, in a typical embodiment, only passive elements such as microlenses, lenses, micromirrors, mirrors, polarization selection and / or tuning elements, beam splitters, spatial filters / beam blockers, etc., may be present. On the distal side (e.g., at spaced locations), a wider variety of elements may be present, potentially including scanning mirrors, spatial light modulators (e.g., digital micromirror devices or liquid crystal-based modulators), filter wheels, tunable color filters, and numerous dichroic mirrors to separate colors onto individual detectors (areas) (such as individual camera chips). For example, elements such as scanning mirrors and spatial light modulators may be used to tune the parameters of irradiation radiation (before reaching the wafer) and / or detection radiation (before reaching the sensor).

[0102] Multiple waveguides 602 can exist to simultaneously measure multiple different / spaced measurement marks on the wafer. For example, these multiple waveguides can each be connected to their own separate source 604 and / or sensor 606, or they can share a common sensor 606 and / or source 604. In some embodiments, multiple waveguides 602 can be used to measure a mark, such as a separate waveguide for illumination and detection, or for measuring different polarizations, etc.

[0103] In comparison, Figure 6A measurement system 650 excluding one or more multi-core waveguides 602 is also illustrated. In measurement system 650, the selection of the (location) of the radiation source (tunability) and detector (e.g., the ability to use a camera) is highly limited. Compared to system 650, system 600 provides a new measurement system design architecture. As described above, system 600 utilizes one or more multi-core waveguides 602 to provide increased functional space for other components of system 600 located near the patterned substrate 608, which can reduce or eliminate some engineering constraints in systems used to measure an increased number of markers, and / or have other advantages.

[0104] In some embodiments, one or more multicore waveguides 602 include one or more multicore optical fibers. In some embodiments, one or more multicore waveguides 602 include super-directional etching in a crystalline material, optical ablation structures, structures formed by layer-by-layer deposition, printed waveguides stacked in multiple layers on a substrate, and / or other structures. For example, in some embodiments, the multicore waveguide 602 can be manufactured by starting with a macroscopically stacked glass rod / (hollow) tube, and then heating and drawing the macroscopically stacked glass rod / (hollow) tube into a multicore optical fiber having a microscopic (lateral) length scale.

[0105] In some embodiments, the spaced-out locations include locations away from one side of the patterned substrate 608 that includes the structure and one or more layers. In some embodiments, the length of one or more multi-core waveguides 602 (e.g., reaching the spaced-out locations, such as opposite sides of the patterned substrate 608) is up to about 0.1 m, 0.25 m, 0.5 m, 1 m, or 10 m (or even longer, if desired).

[0106] As an example, Figure 7The illustration shows end views of three different possible examples of multi-core waveguides 700, 702, and 704 formed as multi-core optical fibers. Each multi-core waveguide 700, 702, and 704 has multiple different individual cores 701, 703, and 705, respectively. Each multi-core waveguide 700, 702, and 704 can have up to 10, 100, 500, 1000, or more individual cores. In some embodiments, the cores can be arranged, for example, in a hexagonal, square, or other periodic lattice; or they can be aperiodic (e.g., more or less random) distribution. The lengths of one or more multi-core waveguides 700, 702, and / or 704 can be up to about 0.1 m, 0.25 m, 0.5 m, 1 m, or 10 m, or even longer, if required to reach spaced-out locations such as opposite sides of a patterned substrate. The radiation in the different cores of one or more multi-core waveguides 700, 702, and / or 704 can be spatially coherent or incoherent relative to each other. Spatial coherence plays a crucial role in image formation. In some embodiments, coherence is required to generate an image; that is, without spatial coherence, image generation will not function. In some embodiments, incoherence helps reduce crosstalk and coherence / scattering artifacts (i.e., it helps improve image formation and thus improve measurement accuracy).

[0107] In some embodiments, radiation source 604 ( Figure 6 One or more multi-core waveguides 700, 702, 704 are configured such that subsets of the cores 701, 703, 705 of the one or more multi-core waveguides 700, 702, 704 are used to conduct radiation from the radiation source 604 to the structure, and such that diffracted light from the structure is captured by different subsets of the cores. In some embodiments, one or more multi-core waveguides 700, 702, 704 are configured to support different wavelength ranges, different diffraction orders, and / or radiation with other characteristics. (Note that these are just examples, and actual implementations of the system may differ. For example, various properties such as low crosstalk, polarization preservation, single spatial mode over a large wavelength range, high core density (i.e., not too large a core spacing), high core number (e.g., 1000), and relatively easy / expensive manufacturing can be provided by a given waveguide in combination.)

[0108] In this example, the multicore waveguide 700 is configured for low crosstalk. Crosstalk refers to optical interference in a given fiber core and / or light in another fiber core that otherwise affects (e.g., leaks into another fiber core), interrupting and / or reducing signals in different fiber cores. In this design, fiber core 701 is positioned to avoid such interference. The multicore waveguide 702 is configured to be polarization-maintaining. This means that waveguide 702 is configured such that light entering fiber core 703 with a specific polarization will leave fiber core 703 with the same polarization. In some embodiments, each fiber core 703 of the multicore waveguide 702 is polarization-maintaining, such that each fiber core 703 supports only one spatial mode with a unique polarization, or it supports two spatial modes with orthogonal polarizations and these two modes do not mix. For example, the two modes may have the same or similar spatial mode distributions. In some embodiments, each fiber core in one or more multicore waveguides is non-polarization-maintaining, such that each fiber core in one or more multicore waveguides supports two modes that have at least approximately the same spatial mode distribution but orthogonal polarizations. Waveguide 704 can be relatively easy to manufacture, for example, and / or can provide a reasonable good trade-off between low crosstalk and high core density (i.e., cores close to each other).

[0109] In some embodiments, radiation source 604 ( Figure 6 The radiation of light can include multiple modes. Spatial (or lateral) modes of light are well-defined and relatively well-known for, for example, waveguides and (some) resonators. In (infinite) free space, spatial modes may not be well-defined because there may be an infinite number of spatial modes. However, when a finite number of spatial modes of a waveguide are coupled into free space and propagate there, this can be called a spatial mode (which can be mapped one-to-one to a waveguide mode). Conversely, light in these spatial modes in free space can be coupled into (a finite number of) waveguide modes, while light in other modes in free space cannot be coupled into waveguide modes (and therefore cannot propagate through waveguides). Typically, a light source can only emit light into those spatial modes that ultimately couple into multimode (or multicore) waveguides. Lenses, including the microlens arrays described herein, can be used to perform “mode matching” between modes in multicore waveguides and modes in free space (as well as modes on the wafer and modes of the light source).

[0110] The number of multiple modes can correspond to (e.g., in the sense that light is coupled to these fiber cores) the number of fiber cores 701, 703, 705. Typically, each fiber core supports one spatial mode of light (although in some embodiments, it is acceptable for each fiber core to support multiple spatial modes).

[0111] The number of fiber cores 701, 703, and 705 can be the total number of fiber cores, or the number of fiber cores 701, 703, and 705 can be a subset of the total number of fiber cores. When the multi-core waveguide is in the image plane with respect to a substrate such as a wafer, it is likely that light will couple to all the fiber cores. However, in such an embodiment, it is also possible that light will couple to (only) a subset of the fiber cores. For example, this can be used to reduce the area of ​​the substrate or wafer that is illuminated. This may be desirable when measuring particularly small measurement marks and it is desirable to avoid illuminating surrounding structures (because light scattered from surrounding structures may interfere with the signal). When the multi-core waveguide is in the Fourier / pupil plane with respect to a substrate (e.g., a wafer), it is likely that light will couple to a subset of the fiber cores; however, it is also possible that light will couple to all the fiber cores.

[0112] In some embodiments, each core 701, 703, 705 of one or more multi-core waveguides 700, 702, 704 conducts radiation in a single spatial mode. The radiation in a single spatial mode can be within the wavelength range of 450 to 1100 nm, 450 to 1100 nm, 450 to 1800 nm, and / or other wavelengths. Each core can, for example, appear to be an infinite single-mode photonic crystal fiber. This facilitates seeing through more materials, such as thicker layers of silicon. (In this case, it may be necessary to use detectors based on non-silicon semiconductors, such as In GaAs or other detectors. For example, in embodiments where many colors are measured in parallel on separate detectors, silicon detectors can be used on separate detectors for silicon-sensitive colors, and other semiconductors can be used for silicon-insensitive colors.) In some embodiments, each core 701, 703, 705 of one or more multi-core waveguides 700, 702, 704 is configured to support 2 to 10 spatial modes in at least a portion of a given wavelength range.

[0113] In some embodiments, radiation source 604 ( Figure 6 The system is configured such that the radiation includes at least pairwise spatial coherence between illumination pattern pairs on opposite sides of the illumination pupil. This allows for the measurement of smaller grating pitches (in a dark-field configuration). For standard dark-field microscopy embodiments and when attempting to measure small grating pitches, there is no interference signal on the detector, meaning that alignment cannot be determined (at least not with good reproducibility and accuracy).

[0114] Figure 8 The illustration shows another example measurement system 800 utilizing one or more multi-core waveguides 802. System 800 can be similar to... Figure 6 The system 600 shown, and / or the above regarding Figure 3The system 10 described is the same as or similar to that of system 600. In some embodiments, one or more components of system 800 may be similar to or the same as one or more components of system 600 and / or system 10. In some embodiments, one or more components of system 800 may replace, be used together with, or otherwise enhance one or more components of system 600 and / or system 10. System 800 includes a radiation source 804, a radiation sensor 806, and / or other components. In this example, radiation source 804 may be configured to provide spatially incoherent radiation 810 with a number of modes equal to the number of cores in one or more multi-core waveguides 802 (e.g., as described above), although other configurations are also possible.

[0115] Figure 8 The illustration shows a first view 801, in which one or more multi-core waveguides 802 are directly above, but still away from, a target structure 803 (e.g., a measurement marker) in a substrate 805 (such as a semiconductor wafer). View 801 illustrates (in light of other details described below) that, in the detection path, the complex field at plane 850 is similar to the complex field at plane 850 on the wafer side. This means that an image of the radiation sensor 806 can be obtained as if the one or more multi-core waveguides 802 were not present at all. In some embodiments, a moiré (or “spatial beat frequency”) pattern can appear on the camera. This moiré / beat frequency pattern is generated by the overlap of two periodic structures, one of which is a grating on the wafer, and the other is the periodicity of the multi-core waveguide cores. This pattern typically occurs when the period of the grating is comparable to the period of the multi-core waveguide, which is true for many relevant use cases.

[0116] In some embodiments, system 800 includes one or more substrate-side optical elements configured to focus radiation 810 from radiation source 804 onto structure 803 and to guide diffracted and / or reflected radiation from structure 803 into one or more multi-core waveguides 802. In this example, the one or more substrate-side optical elements include a microlens array 820, a lens 822, and / or other components. In some embodiments, 820 and / or 830 may be a “standard” microlens array positioned at a distance from the multi-core fiber. Each microlens may be (nominally) identical and / or optimized to fit the corresponding fiber core. In some embodiments, 820 and / or 830 may be 3D printed using, for example, laser lithography, and / or manufactured using other methods. For example, each microlens may be a doublet, triplet, etc., to minimize aberrations over a wide wavelength range and / or for other purposes. Microlenses may be shaped or optimized, for example, using something like focused ion beams. In some embodiments, an imaging system may be present between the multi-core fiber and the microlens array. In some embodiments, the function of the microlens may be provided by a spatial light modulator and / or other components. In some embodiments, micromirrors and / or other components may be used instead of microlenses and / or in addition to microlenses. In some embodiments, the microlenses may be adjusted (or additional segmented elements may be added, closely spaced relative to the microlenses) to adjust the angle of the beam. In some embodiments, the angle of the beam may be such that each beam illuminates the same point on the wafer. This can effectively replace the function of lens 822, allowing 822 to be removed, which would save space and cost, for example.

[0117] Figure 8 The illustration shows a lens with a numerical aperture (NA) of approximately 0.7, but this is just one possible example of many possible NAs. In some embodiments, the number of lenses in the substrate-side microlens array 820 may correspond to the number of fiber cores in one or more multi-core waveguides 802. In this example, each fiber core corresponds to a plane wave on the substrate 805 with a different angle. Each fiber core generates a spot (e.g., approximately 30 μm) on the substrate 805, overfilling small markers such as structure 803. Polarization selection and / or rotation optics and / or other components may also be located between one or more multi-core waveguides 802 and structure 803.

[0118] In some embodiments, system 800 includes one or more source and / or sensor-side optical elements configured to guide radiation 810 from radiation source 804 into one or more multi-core waveguides 802, and to guide diffracted and / or reflected radiation from substrate 805, conducted through one or more multi-core waveguides 802, toward radiation sensor 806. The one or more source and sensor-side optical elements may include, for example, a source and sensor-side microlens array 830, lenses 832, beams, optical cubes 834, path length matching elements 836, and / or other components. In some embodiments, the number of lenses in the source and sensor-side microlens array 830 also corresponds to the number of fiber cores in the one or more multi-core waveguides 802.

[0119] Figure 8 A second view 807 of the system 800 is also illustrated, in which the lengths of one or more multi-core waveguides 802 are exaggerated compared to view 801 to show that the radiation source 804, radiation sensor 806, and / or other components of the system 800 may be located further away from the target structure 803 (e.g., measurement markers) in the substrate 805 than shown in view 801. Note that not every element in view 801 is repeated in view 807. In this example, the lengths of one or more multi-core waveguides 802 in view 807 are approximately 1 meter (1 m) to approximately 10 meters (10 m).

[0120] In some embodiments, system 800 may include more than one radiation sensor 806. Figure 8 In the illustrated embodiment, only a subset of the fiber cores can be illuminated by the source, and at least pairs of illuminated fiber cores are coherent with respect to each other. The 0th-order reflection from the wafer eventually appears in the region marked 0 in 870. This light is blocked. The +1st order of one illumination beam and the -1st order of the opposite illumination beam eventually appear in the pupil, indicated as +1 and -1. These beams pass through the system and reach the detector, where they interfere with each other. It should also be noted that only the diffraction order of the X-ray grating is shown here; all equivalent illumination and detection beams also exist in the Y direction (therefore, the beam blocker 870 shown has fourfold symmetry). It is also important that the illumination is not necessarily perfectly spatially coherent. Embodiments may have coherence between pairs of points in the illumination pupil, but not throughout the entire illumination pupil.

[0121] In some embodiments, system 800 includes one or more optical elements 870 configured to block zero-order light from patterned substrate 805 with respect to first-order or higher-order diffracted light, or to separate it onto different radiation sensors. This can be achieved, for example, using a configuration with wedges (e.g., different wedge angles at different portions of the pupil, so that light from different portions of the pupil is collected in different images at different locations on the sensor). Alternatively and / or also, partial reflectors may be used, which can be positioned at a 45-degree angle with respect to the beam. For example, black areas in 870 can be laterally reflected (at a 90-degree angle with respect to the rest of the beam), while white areas can propagate directly through.

[0122] In some embodiments, one or more optical elements may be located on the radiation sensor side of one or more multi-core waveguides 802. However, in some embodiments, one or more optical elements may be located on the patterned substrate side of one or more multi-core waveguides 802.

[0123] For example, in some embodiments, the multicore waveguide 802 has a subset of cores on one side that guides +1st-order radiation, and another subset of cores on the other side that guides -1st-order radiation. In some embodiments, one or more multicore waveguides 802 include two or more multicore waveguides 802 per radiation sensor 806. Figure 8 The shaded bar 899 within the middle waveguide 802 represents a core of the (single) multi-core waveguide 802. For example, the multi-core waveguide 802 comprises a collection of cores 899. Figure 8 (Multiple multi-core waveguides 802 are not shown).

[0124] Each radiation sensor 806 has two or more multi-core waveguides 802 (although) Figure 8 (Only one multi-core waveguide is shown as an example) may include: a multi-core waveguide 802 configured to deliver radiation to structure 803; and a separate multi-core waveguide 802 configured to conduct radiation for detection. Two or more multi-core waveguides 802 per radiation sensor 806 may include two or more multi-core waveguides 802 for detection, wherein each polarization state diffracted by structure 803 has one multi-core waveguide 802. Two or more multi-core waveguides 802 per radiation sensor 806 may include two or more multi-core waveguides 802 for detection, for the +1st order radiation diffracted by structure 803 (see [link to relevant documentation]). Figure 8 860 in the middle has a multi-core waveguide 802, while for the -1st order radiation diffracted by structure 803 (see Figure 8 The 862 in the model has a second multi-core waveguide 802. Other configurations are also expected. For example, previous measurement systems may have additional multi-core fibers in the optical path. In some embodiments, a "standard" dark-field / bright-field microscope may have additional multi-core fibers in the optical path, etc.

[0125] For some measurement applications, off-axis illumination may be necessary and / or desirable—for example, to enable the measurement of small-pitch gratings, where the pitch is typically equivalent to the wavelength, rather than, for example, twice the wavelength. Figure 9 The illustration shows radiation from sources such as Figure 3 Source 2 shown Figure 6 Source 604 shown Figure 8 The radiation 900 from the source 804 (e.g.) includes off-axis illumination 906 relative to structures 908 (such as alignment marks) in one or more different cores 902 of the multi-core waveguide 904, within the patterned substrate 910. Figure 9 902 in 801 can be equivalent to 802 in 801; 904 can be equivalent to 802 in 807; and so on.

[0126] The multi-core waveguide 904 is configured such that a subset of the fiber cores 902 are used to conduct radiation 900 from the radiation source to the structure 908. In some embodiments, only the relative pairs are spatially coherent with respect to each other. For example, two illumination beams generating the x-diffraction order may be coherent with respect to each other, but may not be coherent with respect to the two beams generating the y-diffraction order.

[0127] In this example, the multi-core waveguide 904 may include up to about 1,600 or more total cores, wherein pairs of two or more cores 902 provide off-axis illumination 906. Figure 9 The illustration shows an end view 948 of a multi-core waveguide 904, in which paired cores 902 provide off-axis illumination 906 at different angles, and how this off-axis illumination 906 illuminates structure 908 in a patterned substrate 910. Various different cores can be configured to carry the illumination to provide off-axis illumination at different angles. Note that these are just two of many possible examples.

[0128] Figure 9 An example substrate-side optical element is also illustrated, configured to focus radiation 900 from a radiation source and fiber core 902 onto structure 908. In this example, one or more substrate-side optical elements include a microlens array 950, a lens 952, and / or other components. Finally, Figure 9 The illustrations show various example dimensions and / or spacing for different components. These example dimensions and / or spacing are for illustrative purposes only and are intended to enhance the reader's understanding. Figure 9 Understanding of the content shown. Other configurations are as expected.

[0129] Figure 10 The illustration shows the effect based on the radiation sensor (such as...) Figure 8The simulated intensity generated by the +1 and -1st order diffraction radiation (1002 and 1004, respectively) of the radiation sensor 806 shown is compared with the x and y position sensor image 1000 (where... Figure 10 The illustration is similar to Figure 8 The measurement system 800 shown in the first view 801 and / or embodiments of the same measurement system are described. Diffracted radiation may be provided to the radiation sensor 806 via one or more multi-core waveguides 802 and / or other components (e.g., as described above). In this example, the position of structure 803 (in this example, an alignment mark) is encoded in the phase difference between the +1st and -1st order diffraction orders. The phase of the interference fringes can be fitted to determine the alignment position.

[0130] Figure 11 The illustration shows radiation that can occur in the different fiber cores 1102, 1104, and 1106 of the multi-core waveguide 1110 (e.g., by...). Figure 11 Example of crosstalk 1100 between fibers (represented by a sine curve in the diagram). As mentioned above, crosstalk refers to radiated interference in a given fiber core and / or otherwise affects the light in another fiber core, interrupting and / or reducing the signal in different fiber cores. In this example, there is crosstalk 1100 between the radiation in fiber core 1104 and the radiation in fibers 1102 and 1106. Crosstalk with an amplitude greater than about 2% can produce, for example, an error of about 0.5 nm. Crosstalk between fiber cores can be controlled through multi-core waveguide designs (e.g., similar to telecommunications multi-core optical fibers with very low crosstalk even after lengths of 100 km or longer), through calibration, and / or through other techniques. Calibration can be performed using one or more library calibration techniques used for similar systems. Library calibration can be important for correcting many effects, not just crosstalk.

[0131] Figure 11The diagram also illustrates a phase compensation / correction element 1120 that can be used in many embodiments. It compensates for the fact that in real-world multi-core optical fibers, each core can have a (slightly) different optical path length, for example, due to variations in core diameter. This can be compensated for using, for example, thin glass sheets for each core. The material can be dispersion-matched to the multi-core fiber, thus phase compensation is applicable over a wide wavelength range—for example, certain crystals or custom-engineered materials may be useful. The material can be electro-optical, liquid crystal-based (e.g., spatial light modulators), static or rapidly switching (e.g., switching when changing colors), polarization-dependent (i.e., compensating for the phase of the two polarization components separately, which can be done with any birefringent active or passive solution), etc. This can be performed by post-processing the multi-core fiber itself. For example, adding or removing material to a single core can be performed to compensate for path length / phase differences with other cores. Adding material can be done, for example, by adding a liquid, curing the material where it needs to be added using a nanoscribe-like system (or shorter wavelengths), removing residual liquid, etc. (Removing material can be, for example, optical ablation or FIB-like processes).

[0132] Figure 12 The illustration shows another example measurement system 1200 utilizing one or more multi-core waveguides 1202. Figure 12 The diagram shows a multi-core waveguide 1202, but more multi-core waveguides can typically be used. System 1200 can have similar... Figure 8 The system shown is 800. Figure 6 The system 600 shown and / or the above regarding Figure 3 The system 10 described herein and / or one or more components identical thereto. System 1200 includes a radiation source 1204, a radiation sensor 1206, and / or other components (similar to the embodiments described above, i.e., including options for tuning / optimizing the illumination and detection beam to obtain optimal measurement performance on the particular product stack / wafer).

[0133] Figure 12The illustration shows one or more multi-core waveguides 1202 positioned directly above a target structure (e.g., a measurement marker) within a substrate 1205 (such as a semiconductor wafer), but still away from the target structure (reference numeral 1203 indicates the superposition of the target structure and the illumination spot). In this example, each core of the one or more multi-core waveguides corresponds to a light spot on the substrate 1205 (e.g., rather than at a certain angle). System 1200 includes one or more substrate-side optics configured to focus radiation 1210 from a radiation source 1204 onto structure 1203 and to guide diffracted and / or reflected radiation from structure 1203 into the one or more multi-core waveguides 1202. In this example, the one or more substrate-side optics include a microlens array 1220, a first lens 1222, a second lens 1224, and / or other components. In some embodiments, there may be approximately 60x miniaturization (or 10x in other embodiments—particularly in cases of smaller core spacing). Similarly, for example, the second lens 1224 may have a numerical aperture of approximately 0.6 to 0.9. At substrate 1205, this arrangement can produce a spot size of approximately 400 nm (e.g., wavelength divided by twice the numerical aperture) and a spot spacing of approximately 0.5 μm. Other example sizes and spacings are expected. Advantageously, system 1200 can combine better resolution and lower crosstalk than previous systems. However, aliasing can occur (e.g., for a discrete number of spots on substrate 1205, a small spacing close to the wavelength of radiation is desired). Also here, the resulting sensor (camera) image (in some embodiments) can be viewed as a moiré / beat frequency pattern between a periodic target structure and a periodic multi-core fiber. This moiré pattern is periodic. There can be multiple ways to derive the target position from the moiré pattern, for example: in some embodiments, the phase of the moiré pattern depends directly on the relative phase between the sensor and the target periodic structure in a manner understood by those skilled in the art; and / or since the phase of the sensor is "fixed," those skilled in the art can derive the target phase from the phase of the moiré pattern.

[0134] Figure 13 The illustration shows yet another example measurement system 1300 utilizing one or more multi-core waveguides 1302 according to an embodiment. System 1300 can be considered, for example, a scanning confocal embodiment. System 1300 can have similar characteristics to... Figure 12 The system shown is 1200. Figure 8 The system shown is 800. Figure 6 The system 600 shown and / or the above regarding Figure 3The system 10 described is one or more of the same components. System 1300 includes a radiation source 1304, a radiation sensor 1306, and / or other components. In this embodiment, the detector may be a fast camera (e.g., capturing 10 images during a single scan marker) or a photodiode array (e.g., one photodiode per fiber core). In both cases, one approach is to first combine the signals into a single image and then perform further processing (such as position fitting).

[0135] Figure 13 The illustration again shows one or more multi-core waveguides 1302 positioned directly above, but still away from, a target structure 1303 (e.g., a measurement marker) within a substrate 1305 (such as a semiconductor wafer). In this example, the size of structure 1303 can be approximately 10 to 16 μm. System 1300 includes one or more substrate-side optical elements configured to focus radiation 1310 from radiation source 1304 onto structure 1303 and to guide diffracted and / or reflected radiation from structure 1303 into one or more multi-core waveguides 1302. In this example, the one or more substrate-side optical elements include a first lens 1322, a second lens 1324, and / or other components. In some embodiments, a scaling ratio of approximately 5:1 may be present in this example. Similarly, for example, the second lens 1324 may have a numerical aperture of approximately 0.6 to 0.9. At substrate 1305, this arrangement can produce a spot size of approximately 400 nm (e.g., wavelength divided by twice the numerical aperture) and a spot spacing of approximately 2 μm. Other example dimensions and spacing are as expected. Figure 13 The diagram also illustrates how a specific scan path 1350 is used to address each available spatial pattern on structure 1303 and / or other structures. System 1300 differs from other systems described herein because it does not include a microlens array and does not address all available spatial patterns on structure 1303 simultaneously (thus requiring only about 100 cores instead of 1000 or more). The elimination of the need for a microlens array and the requirement of only about 100 cores makes this embodiment easier to implement compared to other embodiments. Advantageously, with this configuration, the entire structure 1303 can be resolved, which is beneficial for accuracy. Furthermore, the confocal characteristics of this embodiment help suppress scattered light, depth selection, and other manipulations. Note that other embodiments also possess these advantages, but these advantages may be more relevant to this embodiment.

[0136] Parallel beams can also be used, which can be advantageous compared to a small beam that takes into account substrate damage and / or other conditions. This can be even more suitable for other embodiments where the target structure is illuminated more uniformly.

[0137] Figure 14The illustration depicts a measurement method 1400 utilizing one or more multi-core waveguides. For example, in some embodiments, one or more operations of method 1400 can be performed by or by [other means]. Figure 6 The system 600 shown (and / or Figures 7 to 13 Other systems and / or components shown), Figure 3 System 10 shown, computer system (e.g., such as...) Figure 19 (As shown and described below) and / or implemented in other systems. In some embodiments, method 1400 includes: patterning a structure in one or more layers of a substrate using radiation (operation 1402), generating (operation 1404) a measurement signal, conducting (operation 1406) radiation from a radiation source to the structure using one or more multi-core waveguides, and conducting diffracted and / or reflected radiation from the structure to a radiation sensor, and / or other operations.

[0138] The operation of method 1400 is intended to be illustrative. In some embodiments, method 1400 may be accomplished using one or more additional operations not described and / or one or more operations that need not be discussed. For example, in some embodiments, method 1400 may include additional operations related to determining adjustments for a semiconductor device manufacturing process. Additionally, in Figure 14 The order of operations illustrated in the diagram and described in this paper is not intended to be restrictive.

[0139] In some embodiments, one or more portions of method 1400 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 1400 in response to instructions electronically stored on an electronic storage medium. The one or more processing devices may include devices configured by hardware, firmware, and / or software to be specifically designed to perform one or more operations of method 1400 (e.g., see below with...). Figure 19 (Related discussion).

[0140] In operation 1402, radiation from a radiation source is used to irradiate a structure in one or more layers of a patterned substrate. This structure may include measurement markers and / or other structures. In some embodiments, the structure includes diffraction-based overlapping measurement markers comprising a first grating in a lower layer of the patterned substrate and a second grating in an upper layer of the patterned substrate. The second grating may, for example, be directly above the first grating in the patterned substrate. 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 a user, or determined by a system (e.g., Figure 3 The system 10 and / or shown Figure 6 The system 600 shown is determined based on previous measurements and / or otherwise. 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 can be any radiation suitable for measurement.

[0141] In some embodiments, the radiation source is configured to generate spatially coherent radiation. In some embodiments, the radiation source is configured to generate spatially incoherent and / or partially coherent radiation. In some embodiments, the radiation in different cores of one or more multi-core waveguides is spatially incoherent relative to each other. In some embodiments, the radiation from the radiation source in one or more different cores of one or more multi-core waveguides includes off-axis illumination relative to a structure in a patterned substrate.

[0142] In some embodiments, radiation from a radiation source may include multiple modes. For example, the number of multiple modes may correspond to, for example, the number of cores in one or more multi-core waveguides. The number of cores may be the total number of cores, or, when one or more multi-core waveguides are located in a Fourier and / or pupil plane with respect to a patterned substrate, the number of cores may be a subset of the total number of cores. In some embodiments, each core in one or more multi-core waveguides conducts radiation of a single spatial mode. The radiation of a single spatial mode may cover, for example, wavelength ranges of 450 to 900 nm, 450 to 1100 nm, and / or 450 to 1800 nm. Each core may, for example, resemble an infinite single-mode photonic crystal fiber. In some embodiments, each core in one or more multi-core waveguides is configured to support 2 to 10 spatial modes in at least a portion of a given wavelength range. In some embodiments, the radiation source is configured such that the radiation includes at least pairwise spatial coherence between pairs of illumination modes on opposite sides of the illumination pupil.

[0143] In some embodiments, each core of one or more multi-core waveguides is polarization-preserving, such that each core supports only one spatial mode with a unique polarization, or supports two spatial modes with orthogonal polarizations and these two modes do not mix. For example, the two modes may have the same or similar spatial mode distributions. In some embodiments, each core of one or more multi-core waveguides is non-polarization-preserving, such that each core of one or more multi-core waveguides supports two modes with at least approximately the same spatial mode distribution but orthogonal polarizations. In some embodiments, operation 1402 is performed by a method similar to... Figure 3 The source 2 shown and / or the same radiation source as it are executed.

[0144] In operation 1404, radiation from a radiation source is conducted to the structure, and diffracted and / or reflected radiation from the structure is conducted to a radiation sensor. The conduction is performed using one or more multi-core waveguides, the lengths of which are configured to facilitate the placement of the radiation source and / or radiation sensor relative to the patterned substrate at spaced locations (e.g., as described above). In some embodiments, the radiation source and one or more multi-core waveguides are configured such that a subset of the cores in the one or more multi-core waveguides is used to conduct radiation from the radiation source to the structure, and such that diffracted light from the structure is captured by different subsets of the cores. In some embodiments, the one or more multi-core waveguides are configured to support different wavelength ranges, different diffraction orders, and / or radiation with other characteristics.

[0145] In some embodiments, one or more multi-core waveguides include one or more multi-core optical fibers. In some embodiments, one or more multi-core waveguides include super-directional etching in a crystalline material, optical ablation structures, structures formed by layer-by-layer deposition, and / or printed waveguides stacked in multiple layers on a substrate, and / or other structures.

[0146] The lengths of one or more multi-core waveguides are configured to facilitate the placement of radiation sources and / or radiation sensors at spaced locations relative to the patterned substrate, thereby providing increased functional space for other components of the measurement system located near the patterned substrate. Other components may include, for example, substrate-side microlens arrays and / or other components. In some embodiments, the spaced locations include…

[0147] In some embodiments, the spaced-out locations include locations away from the patterned substrate, comprising the structure and one or more layers on one side. In some embodiments, the length of one or more multicore waveguides can be up to about 0.1 m, 0.25 m, 0.5 m, 1 m, or 10 m (or even longer, if desired).

[0148] In some embodiments, operation 1404 includes focusing radiation from a radiation source onto the structure using one or more substrate-side lenses, and guiding diffracted and / or reflected radiation from the structure into one or more multi-core waveguides. The one or more substrate-side lenses may include, for example, a substrate-side microlens array. The number of lenses in the substrate-side microlens array may correspond to the number of fiber cores in the one or more multi-core waveguides. Polarization selection and / or rotation optics may also be located between the one or more multi-core waveguides and the structure.

[0149] In some embodiments, operation 1404 includes using one or more source and sensor-side lenses to guide radiation from a radiation source into one or more multi-core waveguides, and to guide diffracted and / or reflected radiation from the substrate, conducted through the one or more multi-core waveguides, toward a radiation sensor. The one or more source and sensor-side lenses may include, for example, source and sensor-side microlens arrays and / or other components. In some embodiments, the number of lenses in the source and sensor-side microlens array corresponds to the number of fiber cores in the one or more multi-core waveguides.

[0150] In some embodiments, operation 1404 includes using optical elements to block zero-order light from the patterned substrate with respect to first-order or higher-order diffracted light, or to separate it onto different radiation sensors. In some embodiments, the optical elements are located on the radiation sensor side of one or more multi-core waveguides. However, in some embodiments, the optical elements are located on the patterned substrate side of one or more multi-core waveguides.

[0151] In some embodiments, one or more multicore waveguides include two or more multicore waveguides per radiation sensor. Two or more multicore waveguides per radiation sensor may include: a multicore waveguide configured to deliver radiation to the structure, and a separate multicore waveguide configured to conduct radiation for detection; and / or two or more multicore waveguides for detection, each having one multicore waveguide for each polarization state diffracted by the structure.

[0152] In some embodiments, multiple multi-core waveguides can be tightly stacked together. This can be useful because it may be difficult to manufacture high-quality waveguides with more than 1000 cores that meet all our other specifications in the near future. By tightly stacking multiple waveguides, the same result can be effectively achieved, for example, expanding the field of view on a wafer. Alternatively, different types of waveguides can also be stacked. For example, a multi-core waveguide can be used in the center, surrounded by about four single-mode waveguides at the edges. In this case, for example, the single-mode waveguides can be used for illumination, and the multi-core waveguides can be used for (dark field) detection.

[0153] In operation 1406, a measurement signal is generated based on the diffracted and / or reflected radiation received from the structure. The measurement signal includes measurement information for one or more layers. The measurement information may include, for example, optical measurement information and / or other information. In some embodiments, the measurement information includes alignment position information, overlap information, focus measurement information, exposure dose measurement information, and / or other information.

[0154] In some embodiments, operation 1406 includes generating a measurement signal based on reflected radiation detected from the diffraction grating target(s) as described above. The measurement signal is generated by a sensor (such as...) Figure 3The detector 4 and / or other sensors in the measurement signal are generated based on the radiation received by the sensors. The measurement signal includes measurement information related to the target(s). For example, the measurement signal may be an overlap and / or alignment signal, and / or other measurement signals that include overlap and / or alignment measurement information. The measurement information (e.g., overlap value, alignment value, and / or other information) can be determined using the principles of interferometry and / or other principles.

[0155] In some embodiments, overlap and / or alignment and / or other measurements can be determined in operation 1406. For example, one or more processors (such as the processor PRO described herein) can be configured to determine alignment positions and / or overlaps for one or more layers based on measurement signals. One or more processors can be configured to determine alignment positions and / or overlaps by determining the phase difference between the +1st and -1st diffraction orders of diffracted radiation from the structure (e.g., conducted by different waveguides). For example, a first core (or a subset of first cores) in one or more multi-core waveguides can be configured to conduct +1st-order diffracted radiation from the structure toward the sensor, and a second core in one or more multi-core waveguides is configured to conduct -1st-order diffracted radiation from the structure toward the sensor. Of course, in many embodiments, the subset will depend on the target pitch and wavelength. In a typical embodiment, some cores will conduct +1st-order radiation toward a first wavelength, while other cores will conduct +1st-order radiation toward another wavelength (and so on).

[0156] Overlap and / or alignment can be determined based on diffraction radiation and / or other information from the diffraction grating target. In some embodiments, radiation can be directed onto multiple targets, a single target, a sub-section of a target (e.g., a portion smaller than the whole), and / or otherwise directed onto the substrate. In some embodiments, radiation can be directed onto the target in a time-varying manner. For example, radiation can be rasterized on the target (e.g., by moving the target under radiation) so that different portions of the target are irradiated at different times. As another example, the characteristics of the radiation (e.g., wavelength, intensity, etc.) can be varied. This can create a data envelopment or window for analyzing time-varying variations. The data envelopment can facilitate the analysis of individual sub-sections of the target, comparison of one portion of the target with another and / or with other targets (e.g., in other layers), and / or other analyses.

[0157] The measurement signal includes an electronic signal representing and / or otherwise corresponding to radiation reflected from the target(s). The measurement signal may indicate, for example, measurements associated with a diffraction grating target, and / or other information. Generating the measurement signal includes sensing the reflected radiation and converting the sensed reflected radiation into an electronic 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 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. This sensing and conversion may be performed by a method similar to and / or identical to... Figure 3 The detector 4 and / or processor PRO components and / or other components are executed as shown.

[0158] In some embodiments, method 1400 includes determining adjustments to a semiconductor device fabrication process. In some embodiments, method 1400 includes determining one or more semiconductor device fabrication process parameters. One or more semiconductor device fabrication process parameters may be determined based on one or more detected phase and / or amplitude changes, overlap and / or alignment values ​​indicated by measurement signals, and / or other similar systems and / or other information. One or more parameters may include radiation parameters (radiation used for measurement), overlap values, alignment values, measurement inspection locations on semiconductor device structural layers, radiation beam trajectories across targets, 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. Exposure lens parameters may also be important for control—for example, to adjust the shape of the current exposure layer / field to match the alignment / overlap of the measurement (on one or more previous layers).

[0159] In some embodiments, method 1400 includes determining process adjustments based on one or more determined semiconductor device manufacturing process parameters, adjusting the semiconductor device manufacturing apparatus, and / or other operations based on the determined adjustments. For example, if a determined measurement value is outside the process tolerance, the out-of-tolerance measurement may be caused by one or more manufacturing processes with drifting process parameters and / or otherwise altered, such that the process no longer produces acceptable equipment (e.g., the measurement value may exceed an acceptability threshold). One or more new or adjusted process parameters may be determined based on the measurement determination. The new or adjusted process parameters may be configured to enable the manufacturing process to produce acceptable equipment again.

[0160] For example, new or adjusted process parameters can bring previously unacceptable measurements back into an acceptable range. The new or adjusted process parameters can be compared with existing parameters for a given process. If a difference exists, that difference can be used to determine adjustments to the apparatus used in the production equipment (e.g., parameter "x" should be increased / decreased / changed to match a new or adjusted version of parameter "x" determined as part of method 1400), for example. In some embodiments, method 1400 may include electronic adjustment devices (e.g., based on the determined process parameters). Electronic adjustment devices may include, for example, sending electronic signals and / or other communications to the apparatus, which causes changes in the apparatus. Electronic adjustment may include, for example, changing settings on the apparatus, and / or other adjustments.

[0161] In some embodiments, one or more operations of method 1400 include using one or more actuator synchronizing stages (e.g., WTa, WTb as described above), radiation sensors (e.g. Figure 3 The movement of detector 4 and / or other sensors and / or one or more conduits scans the target structure (e.g., see the description above regarding the various sensors and actuators provided, for example, to obtain the location of the target portion of the structure (e.g., a measurement marker) and bring it below the objective lens). The radiation sensor is configured to generate an image based on diffracted radiation received during the scan. In some embodiments, the scan is continuous, such that the radiation sensor receives an uninterrupted stream of diffracted radiation used to generate the image. In some embodiments, the radiation sensor includes, for example, a camera and / or a scanning mirror. In some embodiments, the radiation sensor includes a camera with a shielding element, and the shielding element remains open throughout the scan.

[0162] For example, Figure 15 The illustration shows a synchronization station 1502 (e.g., WTa, WTb as described above) and a radiation sensor 1504 (e.g. Figure 3The system 1500 uses movement 1501 of detector 4 and / or other sensors and / or one or more conduits 1506 (e.g., different cores of one or more multi-core waveguides as described herein) to scan and measure the target structure 1508. A stage 1502 is configured to hold and move a patterned substrate, such as a semiconductor wafer. The patterned substrate includes the target structure 1508 in one or more layers within the patterned substrate. A radiation sensor 1504 is configured to generate an image 1510 based on diffracted radiation 1512 and / or other information received from the target structure 1508. The image 1510 includes measurement information for one or more layers. One or more conduits 1506 are configured to conduct radiation from a radiation source (e.g., as described above) to the target structure 1508 and to conduct diffracted radiation 1512 from the target structure 1508 to the radiation sensor 1504. One or more conduits 1506 have a length configured to facilitate the placement of a radiation source, radiation sensor 1504, and / or other components of system 1500 (as described above) at spaced locations relative to the patterned substrate. In some embodiments, system 1500 may include one or more substrate-side optical elements, such as microlens array 1560, lenses, and / or other components; one or more sensor-side optical elements, such as microlens array 1562, lenses, and / or other components; and / or other optical elements.

[0163] System 1500 includes one or more actuators 1520 configured to move 1501 of a synchronization stage 1502, a radiation sensor 1504, one or more conduits 1506, and / or other components to scan 1550 a target structure 1508. Figure 15 In the diagram, actuators 1520 are illustrated as coupled to stage 1502. However, additional actuators may be operatively coupled to, for example, sensor 1504, conduit 1506, and / or other components. As described above, these actuators may be provided, for example, to obtain the position of target structure 1508, and / or the position of a target portion of interest in the target structure (e.g., a portion of a measurement marker), and to bring it below objective lens 1530. In some embodiments, these actuators may move stage 1502 relative to other components of system 1500. However, in some embodiments, these actuators may move one or more components of other components of system 1500 (e.g., one or more conduits 1506, radiation sensor 1504, etc.) relative to stage 1502 (and patterned substrate) and / or other components of system 1500. For example, system 1500 may include scanning mirror 1580, which is configured to be actuated in combination with stage 1502 during scanning. This may include, for example, synchronized movement and / or other actuation.

[0164] In some embodiments, one or more actuators 1520 and / or other components of system 1500 are operatively coupled to one or more processors (e.g., processor PRO as described herein). One or more processors may be configured (e.g., via programming instructions and / or based on other information) to control actuators 1520 and / or other components to function as described herein.

[0165] Radiation sensor 1504 is configured to generate image 1510 based on diffracted radiation 1512 received during scanning. In some embodiments, the scanning is continuous, such that radiation sensor 1504 receives an uninterrupted stream of diffracted radiation 1512, which is used to generate image 1510. In some embodiments, radiation sensor 1504 includes a camera, scanning mirror 1580, and / or other components (e.g., as described above). In some embodiments, for example, radiation sensor 1504 may include a camera with a shielding element, and the shielding element remains open throughout the scanning. Other components and operating principles described above with respect to the previously described embodiments may be additionally applied to system 1500.

[0166] Figure 16 The diagram illustrates the scan path 1600 associated with the movement 1501 of stage 1502 and target structure 1508. Various points 1602 and 1604 represent points formed by one or more conduits 1506 (…). Figure 15 The radiation is conducted. In this example, scan path 1600 is linear, approximately two micrometers long, with a scan time of approximately two milliseconds, and has a diagonal orientation relative to the target structure 1508, but other scan paths are also expected. The scan angle and / or length can be adjusted so that the scan includes an integer number of unit cells of the lattice of the multi-core fiber (waveguide). The end position of one fiber core can coincide with the start position of another fiber core.

[0167] Figure 17 The illustration shows one or more radiation sensors from the radiation sensors described herein in a scan-free (e.g., image 1700) and with Figure 15 Sample images 1700 and 1702 are obtained and / or otherwise generated in the case of the aforementioned scan (e.g., image 1702). In some embodiments, such as Figure 17 As shown, scanning (e.g., as...) Figure 15 The image 1702 described herein can produce a cleaner and / or sharper camera image, in contrast to a more aliased image 1700 (e.g., image 1700 has visible dots and / or is more grainy), although both images 1700 and 1702 are useful for the purposes described herein.

[0168] In some embodiments, the local variations within the observed target structure (e.g., measurement markers due to finite size effects) are small (e.g., about 0.1 nm). For a “static” sensor, considerable edge effects cause much larger (e.g., ~1 nm level) local variations. Although many of these local variations are averaged out when determining marker-level alignment positions or overlap values, scanning (e.g., as...) Figure 15 The above provides additional advantages.

[0169] Figure 18 An embodiment 1801 of system 1800 is illustrated, having a phase and / or amplitude mask 1802 located in a Fourier plane on the substrate 1811 side of one or more conduits 1804. Mask 1802 is configured to convert radiation 1830 having a first spatial mode (conducted via various lenses 1840 and / or other components) into radiation having a second spatial mode for illuminating a measurement target structure 1806. In some embodiments, radiation from a radiation source (see previous figures) has a first spatial mode, and diffracted radiation received from structure 1806 for generating an image (see previous figures) has a second spatial mode. In some embodiments, for example, the second spatial mode is orthogonal to the first spatial mode. Note that different spatial modes within the same base are orthogonal by definition. In some embodiments, an embodiment 1803 of system 1800 includes a phase and / or amplitude mask 1820 (e.g., in this example, together with a microlens array 1850) located at each substrate-side end of the core of one or more conduits 1804. Multiple masks 1820 are also configured to convert radiation having a first spatial mode into radiation having a second spatial mode for irradiating the measurement target structure 1806. Embodiments in which the detection radiation is also modulated via phase and / or amplitude masks are also contemplated. In some embodiments, the irradiation and detection radiation pass through the same phase / amplitude mask. In some embodiments, they pass through different phase / amplitude masks. This includes options where only the irradiation branch or the detection branch includes multiple such phase / amplitude elements.

[0170] Note that Example 1801 shows only one fiber core, while in practice there are many fiber cores (as in other embodiments described herein). An important aspect of Example 1801 is that there is only one element (1802) in the pupil plane, whose transition corresponds to the mode of all the fiber cores (i.e., 1802 also transitions the mode coupled from all other fiber cores (not shown) in the illumination direction). This also applies to the detection direction.

[0171] For example, embodiments 1801 and / or 1803 of system 1800 can be considered dark-field embodiments. Dark-field embodiments are embodiments that suppress background signals and / or perform other operations. These embodiments are configured to illuminate and detect radiation of another (orthogonal) spatial mode using one spatial mode. When there is no structure on the patterned substrate (such as a wafer), there is no signal (from the radiation sensor as described above). However, when there is a structure on the wafer (e.g., the edge of a grating line), the dark-field embodiment converts the illumination spatial mode into a detection spatial mode and generates a signal. As an example, a fundamental Gaussian mode can be used for illumination and detection of a ring mode. In some embodiments, any LG_ij (or TEM_ij, etc.) mode can be used if the mode indices i and / or j are not the same for illumination and detection. Figure 18 An example using a phase mask is shown. Multiple modes in illumination and / or detection are enabled via multi-core fiber, allowing each core to support multiple spatial modes (e.g., as described above). Note that... Figure 18 The embodiments shown are illustrated in transmission mode for illustrative purposes. Many practical embodiments operate in reflection mode. In some of these reflection mode embodiments, light in the detection direction passes precisely through the same optics (including 1802, microlenses, multi-core waveguides) that it passes through in the illumination direction. In other reflection mode embodiments, a (non-polarized or polarized) beam splitter separates the illumination and detection paths.

[0172] In some embodiments, each fiber core supports exactly one spatial mode. This mode can be used in both the illumination and detection directions (as is the case in these first dark-field embodiments, the same as in typical bright-field embodiments). The mode conversion in this embodiment is performed by element 1802. Some embodiments can be described as follows: 1. Light is coupled out of the multi-core waveguide in spatial mode 1. Element 1802 converts mode 1 to mode 2. Then, a structure on the wafer converts mode 2 to mode 3. Then, 1802 converts mode 3 back to mode 1. Mode 1 is then coupled into the multi-core waveguide (still only supporting mode 1). If there is no structure on the wafer, the second step is skipped, resulting in no light being coupled into the multi-core waveguide.

[0173] Hardware embodiments for constructing spatial patterns for illumination can be used in these dark field embodiments. Many options are available. For example, a phase (and / or amplitude) mask can be placed in the Fourier plane on the wafer side of a multi-core fiber (e.g., Figure 18-Right). A phase mask can be configured to convert a spatial mode from a multi-core fiber into a desired illumination mode (e.g., a ring) on ​​the wafer. In some embodiments, a phase (and / or amplitude) mask can be placed at the end of each fiber core. This can potentially be combined with microlenses, i.e., microlenses of different shapes can be configured to simultaneously focus and mode-convert light (examples of this type of technology are described below: • https: / / www.nanoscribe.com / en / applications / high-precision-refractive-microoptics / ; • https: / / www.ncbi.nlm.nih.gov / pmc / articles / PMC4931017 / ; • https: / / www.semanticscholar.org / paper / Hybrid-Refractive%E2%80%93Diffractive-Optical-Vortex-Tian-Cao / cbb545fd1acb1eefa83eedae987881732bded6bb; and / or • https: / / www.nanoscribe.com / en / news-insights / news / fiber-based-bessel-beam-generator / etc). In some embodiments, micro-optical devices can be "3D printed" (e.g., nano-written) onto multi-core optical fibers. This and / or other similar techniques can achieve, for example... Figure 18 The embodiment shown on the left. In some embodiments, the multi-core fiber itself can be designed such that each core supports a non-fundamental mode spatial mode (e.g., a vortex), or a selection of multiple modes. In some embodiments, photolithography (e.g., grayscale lithography) can be used to fabricate micro-optical devices.

[0174] Hardware embodiments for selecting one (or more) custom spatial modes in detection are important. The solutions described above for constructing the illumination beam can also be used to select a specific spatial mode for detection. For example, if it is desirable to select a ring mode from a wafer (e.g., the patterned substrate described above), radiation can be converted into the fundamental mode by a phase plate and then coupled into the single-mode fiber core. In this example, for instance, if the fundamental mode comes from the wafer, the phase plate converts it into a ring, and no light is coupled into the single-mode fiber core.

[0175] Some embodiments may include multi-core optical fibers, such that each core supports two spatial modes (without crosstalk). One mode can be used for illumination. For detection, radiation can be coupled to both modes. If there is no structure on the wafer, radiation is typically coupled back to the same mode used for illumination. If there is a structure on the wafer (such as the edges of alignment grating lines), radiation can be coupled to the other mode. On the camera / detection side of the fiber, the modes can then be separated. For example, separation can be performed using phase masks as described above. Mode separation can also be done digitally, i.e., in post-processing software.

[0176] Polarization-based dark-field embodiments can provide alternative methods for suppressing large background signals. For example, in some cases, 99% of the radiation can be reflected from the flat metal surface on top of a wafer stack, with only 1% interacting with the measurement mark. In this case, 99% of the radiation will be suppressed by polarization optics. This can work if the measurement mark changes polarization (which is often the case). Examples include: illuminating with left-handed circularly polarized light and (only) detecting right-handed circularly polarized light, which can be achieved by placing a polarizer and a quarter-wave plate between a multi-core fiber and the wafer; illuminating with linear polarization (e.g., diagonal) and detecting orthogonal linear polarization (e.g., another diagonal); and / or, if the system remains polarized, or if two component sets are used for the two polarization states, the polarization optics can be placed on the radiation sensor / detector side (rather than the substrate or wafer side). In some embodiments, the system can be configured to "only" utilize linearly polarized light for illumination. The linear polarization can be, for example, horizontal or vertical, such as at a 45-degree angle. The mark can (optionally) be designed to rotate the polarization to the maximum extent. In the detection direction, linear polarization rotated 90 degrees with respect to the illuminating polarization is detected.

[0177] In some embodiments, a polarization-preserving multi-core fiber (waveguide) can be used. In these embodiments, each core can support two modes (one mode for each polarization) and they are not mixed. In these embodiments, illumination and detection can pass through the same multi-core fiber and remain separate. Optionally, a polarization beam splitter can be used in detection to separate cross-polarized and co-polarized images. The cross-polarized image can be a dark-field image (i.e., without a large bright background), while the co-polarized image is more like a bright-field image.

[0178] In some embodiments, the systems and methods described herein provide high-quality (spatially incoherent) imaging of very small markers (e.g., gratings as small as 5x5 micrometers); excellent position maps and excellent expected accuracy with virtually no edge effects; robustness to surrounding structures around the target structure; resolution of intra-mark effects, which can contribute to improved accuracy; achievement of very large (e.g., 10 micrometers) capture range, which is important for advanced packaging applications (e.g., exposing wafers with bonded chips, etc.); small wafer-side size of the system, which makes it possible to fabricate parallel aligned sensors (measuring 1000 markers per wafer); and / or other advantages.

[0179] In some embodiments of one or more systems described herein, optics can be added and / or tuned at the far end of the optical fiber, on the spacious sensor / detector side (e.g., as described above). For example, the spot size on the wafer can be tuned by irradiating a larger or smaller number of fiber cores (i.e., with active components on the wafer side); more than 12 colors can be measured in parallel using parallel cameras on the sensor / detector side (i.e., without space and heat issues on the wafer side); and so on.

[0180] This system and method are robust to thermal and mechanical fluctuations in optical fibers. For example, different fiber cores contribute independently (and incoherently) to the radiation used to form the image. If the optical path length in some fiber cores changes with respect to other fiber cores, for example due to thermal or mechanical effects, this does not affect the measurement performance. Other advantages are also expected.

[0181] Figure 19 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 conveying information, and a processor PRO coupled to the bus BS (or similar to and / or identical to) for processing information. Figure 3 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 executed by the processor PRO. The main memory MM can 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 SD, such as disks or optical discs, are provided and coupled to the bus BS for storing information and instructions.

[0182] A computer system (CS) can be coupled 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 devices (IDs), including alphanumeric and other keys, are coupled to the bus (BS) to communicate 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, to communicate directional information and command selections to the processor (PRO) and to control cursor movement on the display (DS). This input device typically has two degrees of freedom on two axes (a first axis, e.g., x) and a second axis, e.g., y), allowing the device to specify its position in a plane. Touch panel (screen) displays can also be used as input devices.

[0183] In some embodiments, all or part of the operations described herein can be executed by a computer system CS in response to processor PRO executing one or more sequences of one or more instructions contained in main memory MM. These instructions may be read into main memory MM from another computer-readable medium, such as storage device SD. Execution of the sequence of instructions contained 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 sequence of instructions contained in main memory MM. In some embodiments, hardwired circuitry may be used in place of or in combination with software instructions. Therefore, the description herein is not limited to any particular combination of hardware circuitry and software.

[0184] 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. Non-volatile media include, for example, optical discs or hard disks, such as storage devices (SDs). Volatile media include dynamic memory, such as main memory (MMs). Transmission media include coaxial cables, copper wires, and optical fibers, including conductors forming a bus (BS). Transmission media can also take the form of acoustic or optical waves, such as those generated during radio frequency (RF) and infrared (IR) data communications. Computer-readable media can be non-transitory, such as floppy disks, flexible disks, hard disks, magnetic tape, any other magnetic media, CD-ROMs, DVDs, any other optical media, punched cards, paper tape, any other physical media with a perforated pattern, RAM, PROMs and EPROMs, FLASH-EPROMs, any other memory chips, or cassette tapes. Instructions may be recorded on non-transitory computer-readable media. These instructions, when executed by a computer, can perform any of the operations described herein. Transient computer-readable media may include, for example, carrier waves or other propagated electromagnetic signals.

[0185] Various forms of computer-readable media can involve carrying one or more sequences of one or more instructions to a processor PRO for execution. For example, the instructions may initially be carried on a disk of a remote computer. The remote computer may load the instructions into its dynamic memory and transmit them over a telephone line using a modem. A modem local to the computer system CS can receive data over the telephone line and convert the data into an infrared signal using an infrared transmitter. An infrared detector coupled to a bus BS can receive the data carried in the infrared signal and place the data on the bus BS. The bus BS carries the data to main memory MM, which the processor PRO retrieves and executes the instructions. The instructions received by main memory MM may optionally be stored on a storage device SD before or after execution by the processor PRO.

[0186] 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 the local 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.

[0187] A network link (NDL) typically provides data communication to other data devices over one or more networks. For example, a network link NDL can provide a connection to a host computer (HC) via a local network (LAN). This can include data communication services provided through a global packet data communication network now commonly referred to as the "Internet" (INT). A local network (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 through the communication interface (CI) (which carries digital data to and from the computer system (CS)), are exemplary forms of carriers for transmitting information.

[0188] Computer system CS can send and receive messages, including program code, via networks (multiple), network data links (NDL), and communication interfaces (CI). In the Internet example, host computer HC can send request codes for applications via Internet (INT), network data links (NDL), local network (LAN), and communication interface (CI). For example, a download 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 device SD or other non-volatile memory for later execution. In this way, computer system CS can obtain application code in carrier form.

[0189] Various embodiments of this system and method are disclosed in the following list of numbered clauses. Further features, characteristics, and exemplary technical solutions of this disclosure will be described below in accordance with clauses that may be optionally claimed in any combination: 1. A semiconductor measurement system comprising: a radiation source configured to radiate a structure in one or more layers of a patterned substrate; a radiation sensor configured to generate a measurement signal based on diffracted and / or reflected radiation received from the structure, the measurement signal including measurement information for the one or more layers; and one or more multi-core waveguides configured to conduct radiation from the radiation source to the structure and to conduct the diffracted and / or reflected radiation from the structure to the radiation sensor, the lengths of the one or more multi-core waveguides being configured to facilitate the placement of the radiation source and / or the radiation sensor relative to the patterned substrate at spaced-out locations. 2. The system according to Clause 1 further includes one or more substrate-side lenses configured to focus the radiation from the radiation source onto the structure and to direct the diffracted and / or reflected radiation from the structure into the one or more multi-core waveguides. 3. The system according to any one of the preceding clauses, wherein the one or more substrate-side lenses comprise a substrate-side microlens array. 4. The system according to any one of the preceding clauses, wherein the number of lenses in the substrate-side microlens array corresponds to the number of fiber cores in the one or more multi-core waveguides. 5. The system according to any one of the foregoing clauses, wherein the length of said one or more multi-core waveguides is configured to facilitate the placement of the radiation source and / or the radiation sensor relative to the patterned substrate at spaced locations, thereby providing increased functional space for other components of the measurement system located near the patterned substrate. These other components include, for example, the substrate-side microlens array. 6. The system according to any one of the preceding clauses further includes one or more source and sensor-side lenses configured to direct the radiation from the radiation source into the one or more multi-core waveguides and to direct the diffracted and / or reflected radiation from the substrate conducted through the one or more multi-core waveguides toward the radiation sensor. 7. The system according to any one of the preceding clauses, wherein the one or more source and sensor-side lenses comprise source and sensor-side microlens arrays. 8. The system according to any one of the preceding clauses, wherein the number of lenses in the source and sensor-side microlens array corresponds to the number of fiber cores in the one or more multi-core waveguides. 9. The system according to any one of the preceding clauses, wherein the spaced-out location includes a location on one side of the patterned substrate that includes the structure and the one or more layers. 10. The system according to any one of the preceding clauses, wherein the length of said one or more multi-core waveguides is up to about 0.1 m, 0.25 m, 0.5 m, 1 m or 10 m. 11. The system according to any one of the preceding clauses, wherein the radiation source is configured to generate spatially incoherent and / or partially coherent radiation, and the radiation from the radiation source comprises multiple modes. 12. The system according to any one of the preceding clauses, wherein the number of the plurality of modes corresponds to the number of fiber cores in the one or more multi-core waveguides. 13. The system according to any one of the preceding clauses, wherein the number of cores is the total number of cores. 14. The system according to any one of the preceding clauses, wherein when the one or more multi-core waveguides are in the Fourier and / or pupil planes with respect to the patterned substrate, the number of cores is a subset of the total number of cores. 15. The system according to any one of the preceding clauses, wherein each core of the one or more multi-core waveguides conducts radiation of a single spatial mode. 16. The system according to any one of the preceding clauses, wherein the radiation of the single spatial mode covers a wavelength range of 450 to 900 nm, 450 to 1100 nm, and / or 450 to 1800 nm. 17. The system according to any one of the preceding clauses, wherein each core of the one or more multi-core waveguides is configured to support 2 to 10 spatial modes in at least a portion of a given wavelength range. 18. The system according to any one of the preceding clauses, wherein each core in the one or more multi-core waveguides is polarization-preserving, such that each core supports only one spatial mode with a unique polarization, or supports two spatial modes with orthogonal polarizations and the two modes do not mix, wherein the two modes have the same or similar spatial mode distribution. 19. The system according to any one of the preceding clauses, wherein each core of the one or more multi-core waveguides is non-polarization-preserving, such that each core of the one or more multi-core waveguides supports two modes having at least approximately the same spatial mode distribution but orthogonal polarization. 20. The system according to any one of the preceding clauses, wherein the radiation in the different cores of the one or more multi-core waveguides is spatially incoherent with respect to each other. 21. The system according to any one of the preceding clauses, wherein the radiation source is configured to generate spatially coherent radiation. 22. The system according to any one of the preceding clauses, wherein radiation from the radiation source in one or more different cores of the one or more multi-core waveguides includes off-axis irradiation relative to the structure in the patterned substrate. 23. The system according to any one of the preceding clauses, wherein a first core in one or more multi-core waveguides is configured to conduct +1st order diffraction radiation from the structure toward the sensor, and a second core in one or more multi-core waveguides is configured to conduct -1st order diffraction radiation from the structure toward the sensor. 24. The system according to any one of the preceding clauses, wherein the radiation source and the one or more multi-core waveguides are configured such that a subset of the cores in the one or more multi-core waveguides are used to conduct the radiation from the radiation source to the structure, and such that diffracted light from the structure is captured by different subsets of the cores. 25. The system according to any one of the preceding clauses further includes an optical element configured to block zero-order light from the patterned substrate with respect to first-order or higher-order diffracted light, or to separate the zero-order light onto different radiation sensors. 26. The system according to any one of the preceding clauses, wherein the optical element is located on the radiation sensor side of the one or more multi-core waveguides. 27. The system according to any one of the preceding clauses, wherein the optical element is located on the patterned substrate side of the one or more multi-core waveguides. 28. The system according to any one of the preceding clauses, wherein the radiation source is configured such that the radiation includes at least pairwise spatial coherence between pairs of illumination patterns on opposite sides of the illumination pupil. 29. The system according to any one of the preceding clauses further includes one or more processors configured to determine alignment positions and / or overlaps for the one or more layers based on the measurement signals. 30. The system according to any one of the preceding clauses, wherein the one or more processors are configured to determine the alignment position and / or overlap by determining the phase difference between the +1st and -1st diffraction orders of the diffraction radiation from the structure. 31. The system according to any one of the preceding clauses, wherein the structure includes measurement markers. 32. The system according to any one of the preceding clauses, wherein the structure includes diffraction-based overlapping measurement markers, the diffraction-based overlapping measurement markers including a first grating in a lower layer of the patterned substrate and a second grating in an upper layer of the patterned substrate. The second grating may be located directly above the first grating in the patterned substrate; and the measurement signal may be configured for use by one or more processors to adjust the semiconductor device manufacturing process. 33. The system according to any one of the preceding clauses, wherein the measurement information includes optical measurement information. 34. The system according to any one of the preceding clauses, wherein the measurement information includes alignment position information, overlap information, focus measurement information, and / or exposure dose measurement information. 35. The system according to any one of the preceding clauses, wherein the one or more multicore waveguides comprise two or more multicore waveguides per radiation sensor. 36. The system according to any one of the preceding clauses, wherein the two or more multi-core waveguides per radiation sensor may comprise: a multi-core waveguide configured to deliver radiation to the structure, and a separate multi-core waveguide configured to conduct radiation for detection; and / or two or more multi-core waveguides for the detection, each having one multi-core waveguide for each polarization state diffracted by the structure. 37. The system according to any one of the preceding clauses, wherein the one or more multi-core waveguides are configured to support different wavelength ranges. 38. The system according to any one of the preceding clauses further includes polarization selection and / or rotation optics located between the one or more multi-core waveguides and the structure. 39. The system according to any one of the preceding clauses, wherein the one or more multi-core waveguides comprise one or more multi-core optical fibers. 40. The system according to any one of the preceding clauses, wherein the one or more multi-core waveguides comprise super-directional etching in a crystalline material, an optical ablation structure, a structure formed by layer-by-layer deposition, and / or a printed waveguide stacked in multiple layers on a substrate. 41. A semiconductor measurement method comprising: irradiating a structure in one or more layers of a patterned substrate using a radiation source; generating a measurement signal based on diffracted and / or reflected radiation received from the structure using a radiation sensor, the measurement signal including measurement information for the one or more layers; and conducting radiation from the radiation source to the structure and diffracted and / or reflected radiation from the structure to the radiation sensor using one or more multi-core waveguides, the lengths of the one or more multi-core waveguides being configured to facilitate placing the radiation source and / or the radiation sensor at spaced-apart locations relative to the patterned substrate. 42. The method according to Clause 41 further comprises using one or more substrate-side lenses to focus the radiation from the radiation source onto the structure and to guide the diffracted and / or reflected radiation from the structure into the one or more multi-core waveguides. 43. The method according to any one of the preceding clauses, wherein the one or more substrate-side lenses comprise a substrate-side microlens array. 44. The method according to any one of the preceding clauses, wherein the number of lenses in the substrate-side microlens array corresponds to the number of fiber cores in the one or more multi-core waveguides. 45. The method according to any one of the preceding clauses, wherein the length of the one or more multi-core waveguides is configured to facilitate the placement of the radiation source and / or the radiation sensor relative to the patterned substrate at spaced locations, thereby providing increased functional space for other components of the measurement system located near the patterned substrate. The other components include, for example, the substrate-side microlens array. 46. ​​The method according to any one of the preceding clauses further includes using one or more source and sensor-side lenses to guide the radiation from the radiation source into the one or more multi-core waveguides, and to guide the diffracted and / or reflected radiation from the substrate conducted through the one or more multi-core waveguides toward the radiation sensor. 47. The method according to any one of the preceding clauses, wherein the one or more source and sensor-side lenses comprise source and sensor-side microlens arrays. 48. The method according to any one of the preceding clauses, wherein the number of lenses in the source and sensor-side microlens array corresponds to the number of fiber cores in the one or more multi-core waveguides. 49. The method according to any one of the preceding clauses, wherein the spaced-out location includes a location away from the patterned substrate on one side comprising the structure and the one or more layers. 50. The method according to any one of the preceding clauses, wherein the length of said one or more multi-core waveguides is up to about 0.1 m, 0.25 m, 0.5 m, 1 m or 10 m. 51. The method according to any one of the preceding clauses, wherein the radiation source is configured to generate spatially incoherent and / or partially coherent radiation, and the radiation from the radiation source comprises multiple modes. 52. The method according to any one of the preceding clauses, wherein the number of the plurality of modes corresponds to the number of fiber cores in the one or more multi-core waveguides. 53. The method according to any one of the preceding clauses, wherein the number of cores is the total number of cores. 54. The method according to any one of the preceding clauses, wherein when the one or more multi-core waveguides are in the Fourier and / or pupil planes with respect to the patterned substrate, the number of cores is a subset of the total number of cores. 55. The method according to any one of the preceding clauses, wherein each core in the one or more multi-core waveguides conducts radiation of a single spatial mode. 56. The method according to any one of the preceding clauses, wherein the radiation of the single spatial mode covers a wavelength range of 450 to 900 nm, 450 to 1100 nm, and / or 450 to 1800 nm. 57. The method according to any one of the preceding clauses, wherein each core of the one or more multi-core waveguides is configured to support 2 to 10 spatial modes in at least a portion of a given wavelength range. 58. The method according to any one of the preceding clauses, wherein each core in the one or more multi-core waveguides is polarization-preserving, such that each core supports only one spatial mode with a unique polarization, or supports two spatial modes with orthogonal polarizations and the two modes do not mix, wherein the two modes have the same or similar spatial mode distribution. 59. The method according to any one of the preceding clauses, wherein each core of the one or more multi-core waveguides is non-polarization-preserving, such that each core of the one or more multi-core waveguides supports two modes having at least approximately the same spatial mode distribution but orthogonal polarization. 60. The method according to any one of the preceding clauses, wherein the radiation in the different cores of the one or more multi-core waveguides is spatially incoherent with respect to each other. 61. The method according to any one of the preceding clauses, wherein the radiation source is configured to generate spatially coherent radiation. 62. The method according to any one of the preceding clauses, wherein radiation from the radiation source in one or more different cores of the one or more multi-core waveguides comprises off-axis irradiation relative to the structure in the patterned substrate. 63. The method according to any one of the preceding clauses, wherein a first core in one or more multi-core waveguides is configured to conduct +1st order diffraction radiation from the structure toward the sensor, and a second core in one or more multi-core waveguides is configured to conduct -1st order diffraction radiation from the structure toward the sensor. 64. The method according to any one of the preceding clauses, wherein the radiation source and the one or more multi-core waveguides are configured such that a subset of the cores in the one or more multi-core waveguides are used to conduct the radiation from the radiation source to the structure, and such that the diffracted light from the structure is captured by different subsets of the cores. 65. The method according to any one of the preceding clauses further includes using optical elements to block the 0th-order light from the patterned substrate with respect to the 1st or higher-order diffracted light, or separating the 0th-order light onto different radiation sensors. 66. The method according to any one of the preceding clauses, wherein the optical element is located on the radiation sensor side of the one or more multi-core waveguides. 67. The method according to any one of the preceding clauses, wherein the optical element is located on the patterned substrate side of the one or more multi-core waveguides. 68. The method according to any one of the preceding clauses, wherein the radiation source is configured such that the radiation includes at least pairwise spatial coherence between pairs of illumination patterns on opposite sides of the illumination pupil. 69. The method according to any one of the preceding clauses further includes one or more processors configured to determine alignment positions and / or overlaps for the one or more layers based on the measurement signals. 70. The method according to any one of the preceding clauses, wherein the one or more processors may be configured to determine the alignment position and / or overlap by determining the phase difference between the +1st and -1st diffraction orders of the diffraction radiation from the structure. 71. The method according to any one of the preceding clauses, wherein the structure includes measurement markers. 72. The method according to any one of the preceding clauses, wherein the structure includes diffraction-based overlapping measurement markers, the diffraction-based overlapping measurement markers including a first grating in a lower layer of the patterned substrate and a second grating in an upper layer of the patterned substrate. The second grating may be located directly above the first grating in the patterned substrate; and the measurement signal may be configured for use by one or more processors to adjust the semiconductor device manufacturing process. 73. The method according to any one of the preceding clauses, wherein the measurement information includes optical measurement information. 74. The method according to any one of the preceding clauses, wherein the measurement information includes alignment position information, overlap information, focus measurement information, and / or exposure dose measurement information. 75. The method according to any one of the preceding clauses, wherein the one or more multi-core waveguides comprise two or more multi-core waveguides per radiation sensor. 76. The method according to any one of the preceding clauses, wherein the two or more multi-core waveguides per radiation sensor may comprise: a multi-core waveguide configured to deliver radiation to the structure, and a separate multi-core waveguide configured to conduct radiation for detection; and / or two or more multi-core waveguides for the detection, each having one multi-core waveguide for each polarization state diffracted by the structure. 77. The method according to any one of the preceding clauses, wherein the one or more multi-core waveguides are configured to support different wavelength ranges. 78. The method according to any one of the preceding clauses, wherein a polarization selection and / or rotation optics is positioned between the one or more multi-core waveguides and the structure. 79. The method according to any one of the preceding clauses, wherein the one or more multi-core waveguides comprise one or more multi-core optical fibers. 80. The method according to any one of the preceding clauses, wherein the one or more multi-core waveguides comprise super-directional etching in a crystalline material, an optical ablation structure, a structure formed by layer-by-layer deposition, and / or a printed waveguide stacked in multiple layers on a substrate. 81. A semiconductor metrology system comprising: a stage configured to hold and / or move a patterned substrate, the patterned substrate including a metrology target structure in one or more layers of the patterned substrate; a radiation sensor configured to generate an image based on diffracted radiation received from the target structure, the image including metrology information for the one or more layers; one or more conduits configured to conduct radiation from a radiation source to the target structure and to conduct the diffracted radiation from the target structure to the radiation sensor, the lengths of the one or more conduits being configured to facilitate positioning the radiation source and / or the radiation sensor relative to the patterned substrate at spaced-apart locations; and one or more actuators configured to synchronize movement of the stage, the radiation sensor, and / or the one or more conduits to scan the metrology target structure, wherein the radiation sensor is configured to generate the image based on diffracted radiation received during the scanning. 82. The system according to Clause 81, wherein the one or more conduits comprise one or more multicore waveguides. 83. The system according to any one of the preceding clauses, wherein the scanning is continuous, such that the radiation sensor receives an uninterrupted stream of diffracted radiation, the uninterrupted stream of diffracted radiation being used to generate the image. 84. The system according to any one of the preceding clauses, wherein the radiation sensor includes a camera with a shield, and wherein the shield remains open throughout the entire duration of the scan. 85. The system according to any one of the preceding clauses, wherein the radiation sensor includes a camera, and synchronizing the movement of the radiation sensor includes synchronizing the movement of the camera. 86. The system according to any one of the preceding clauses, wherein the radiation sensor comprises a camera and a scanning mirror, and synchronizing the movement of the radiation sensor comprises synchronizing the movement of the scanning mirror while the camera remains stationary. 87. The system according to any one of the preceding clauses further includes one or more sensor-side lenses configured to direct the radiation from the radiation source into the one or more conduits and to direct the diffracted radiation from the substrate conducted through the one or more conduits toward the radiation sensor. 88. The system according to any one of the preceding clauses, wherein the one or more sensor-side lenses comprise a sensor-side microlens array. 89. The system according to any one of the preceding clauses, wherein the number of lenses in the sensor-side microlens array corresponds to the number of fiber cores in the one or more catheters. 90. The system according to any one of the preceding clauses, wherein the radiation from the radiation source has a first spatial mode, and the diffracted radiation received from the structure for generating the image has a second spatial mode. 91. The system according to any one of the preceding clauses, wherein the second spatial pattern is orthogonal to the first spatial pattern. 92. The system according to any one of the preceding clauses further includes a phase and / or amplitude mask located in the Fourier plane of the system on the substrate side of the one or more conduits, the mask being configured to convert radiation having the first spatial mode into radiation having the second spatial mode for irradiating the measurement target structure. 93. The system according to any one of the preceding clauses further includes a phase and / or amplitude mask located at each substrate-side end of the fiber core of the one or more conduits, the mask being configured to convert radiation having the first spatial mode into radiation having the second spatial mode for irradiating the measurement target structure. 94. The system according to any one of the preceding clauses, wherein the scan is linear and diagonally oriented across the target structure, lasts for approximately two milliseconds, and covers a distance of approximately two micrometers. 95. The system according to any one of the preceding clauses, wherein the length of the one or more conduits is configured to facilitate the placement of the radiation source and / or the radiation sensor at spaced locations relative to the patterned substrate, thereby providing increased functional space for other components of the measurement system located near the patterned substrate. 96. The system according to any one of the preceding clauses, wherein a first core of the one or more catheters is configured to conduct +1 order diffraction radiation from the target structure toward the sensor, and a second core of the one or more catheters is configured to conduct -1 order diffraction radiation from the target structure toward the sensor. 97. The system according to any one of the preceding clauses, wherein the radiation source and the one or more conduits are configured such that a core subset of the one or more conduits is used to conduct the radiation from the radiation source to the target structure, and such that diffracted light from the target structure is captured by different core subsets. 98. The system according to any one of the foregoing clauses further includes one or more processors configured to determine alignment positions and / or overlaps for the one or more layers based on the image. 99. The system according to any one of the preceding clauses, wherein the one or more processors are configured to determine the alignment position and / or overlap by determining the phase difference between the +1 and -1 diffraction orders of the diffraction radiation from the target structure. 100. The system according to any one of the preceding clauses, wherein the target structure includes a diffraction-based overlay measurement mark, the diffraction-based overlay measurement mark including a first grating in a lower layer of a patterned substrate and a second grating in an upper layer of a patterned substrate, wherein the second grating is located directly above the first grating in the patterned substrate; and wherein the image is configured to be used by one or more processors to adjust a semiconductor device manufacturing process. 101. A semiconductor metrology method comprising: holding and / or moving a patterned substrate using a stage, the patterned substrate including a measurement target structure in one or more layers of the patterned substrate; generating an image based on diffracted radiation received from the target structure using a radiation sensor, the image including metrology information for the one or more layers; conducting radiation from a radiation source to the target structure and from the diffracted radiation to the radiation sensor using one or more conduits, the lengths of the one or more conduits being configured to facilitate positioning the radiation source and / or the radiation sensor relative to the patterned substrate at spaced-apart locations; and synchronizing the movement of the stage, the radiation sensor, and / or the one or more conduits using one or more actuators to scan the measurement target structure, wherein the radiation sensor is configured to generate the image based on diffracted radiation received during the scan. 102. The method according to Clause 101, wherein the one or more conduits comprise one or more multicore waveguides. 103. The method according to any one of the preceding clauses, wherein the scanning is continuous, such that the radiation sensor receives an uninterrupted stream of diffracted radiation, the uninterrupted stream of diffracted radiation being used to generate the image. 104. The method according to any one of the preceding clauses, wherein the radiation sensor includes a camera with a shield, and wherein the shield remains open throughout the entire duration of the scan. 105. The method according to any one of the preceding clauses, wherein the radiation sensor includes a camera, and synchronizing the movement of the radiation sensor includes synchronizing the movement of the camera. 106. The method according to any one of the preceding clauses, wherein the radiation sensor comprises a camera and a scanning mirror, and synchronizing the movement of the radiation sensor comprises synchronizing the movement of the scanning mirror while the camera remains stationary. 107. The method according to any one of the preceding clauses further includes using one or more sensor-side lenses to guide the radiation from the radiation source into the one or more conduits, and guiding the diffracted radiation from the patterned substrate conducted through the one or more conduits toward the radiation sensor. 108. The method according to any one of the preceding clauses, wherein the one or more sensor-side lenses comprise a sensor-side microlens array. 109. The method according to any one of the preceding clauses, wherein the number of lenses in the sensor-side microlens array corresponds to the number of fiber cores in the one or more catheters. 110. The method according to any one of the preceding clauses, wherein the radiation from the radiation source has a first spatial pattern, and the diffracted radiation received from the target structure and used to generate the image has a second spatial pattern. 111. The method according to any one of the preceding clauses, wherein the second spatial pattern is orthogonal to the first spatial pattern. 112. The method according to any one of the preceding clauses further includes using a phase and / or amplitude mask located in the Fourier plane of the system on the substrate side of the one or more conduits to convert radiation having the first spatial mode into radiation having the second spatial mode for irradiating the measurement target structure. 113. The method according to any one of the preceding clauses further includes using a phase and / or amplitude mask located at each substrate-side end of the fiber core of the one or more conduits to convert radiation having the first spatial mode into radiation having the second spatial mode for irradiating the measurement target structure. 114. The method according to any one of the preceding clauses, wherein the scan is linear and diagonally oriented across the target structure, lasts for about two milliseconds, and covers a distance of about two micrometers. 115. The method according to any one of the preceding clauses, wherein the length of the one or more conduits is configured to facilitate the placement of the radiation source and / or the radiation sensor at spaced locations relative to the patterned substrate, thereby providing increased functional space for other components of the measurement system located near the patterned substrate. 116. The method according to any one of the preceding clauses, wherein a first core of the one or more catheters is configured to conduct +1st order diffraction radiation from the target structure toward the sensor, and a second core of the one or more catheters is configured to conduct -1st order diffraction radiation from the target structure toward the sensor. 117. The method according to any one of the preceding clauses, wherein the radiation source and the one or more conduits are configured such that a core subset of the one or more conduits is used to conduct the radiation from the radiation source to the target structure, and such that diffracted light from the target structure is captured by different core subsets. 118. The method according to any one of the preceding clauses further includes using one or more processors to determine alignment positions and / or overlaps for the one or more layers based on the image. 119. The method according to any one of the preceding clauses, wherein the one or more processors are configured to determine the alignment position and / or overlap by determining the phase difference between the +1 and -1 diffraction orders of the diffraction radiation from the target structure. 120. The method according to any one of the preceding clauses, wherein the target structure includes a diffraction-based overlay measurement mark, the diffraction-based overlay measurement mark including a first grating in a lower layer of a patterned substrate and a second grating in an upper layer of a patterned substrate, wherein the second grating is located directly above the first grating in the patterned substrate; and wherein the image is configured to be used by one or more processors to adjust a semiconductor device manufacturing process.

[0190] The concepts disclosed herein can be associated with any general imaging system used for imaging subwavelength features, and are particularly applicable to emerging imaging technologies capable of generating increasingly shorter wavelengths. Emerging technologies already in use include EUV (Extreme Ultraviolet) and DUV lithography, which can generate wavelengths of 193 nm using ArF lasers, and even 157 nm using fluorine lasers. Furthermore, EUV lithography can generate wavelengths in the 20 to 5 nm range by using synchrotrons or by utilizing high-energy electrons to bombard materials (solid-state or plasma) to generate photons in the 20 to 5 nm range.

[0191] 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, such as those used for imaging on substrates other than silicon wafers. Furthermore, combinations and sub-combinations of the disclosed elements can include individual embodiments.

[0192] The above description is intended to be illustrative and not restrictive. 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 listed below.

Claims

1. A semiconductor measurement system, comprising: A radiation source configured to radiate structures in one or more layers of a patterned substrate; A radiation sensor configured to generate a measurement signal based on diffracted and / or reflected radiation received from the structure, the measurement signal including measurement information for the one or more layers; as well as One or more multi-core waveguides are configured to conduct radiation from the radiation source to the structure and to conduct diffracted and / or reflected radiation from the structure to the radiation sensor. The lengths of the one or more multi-core waveguides are configured to facilitate the placement of the radiation source and / or the radiation sensor at spaced locations relative to the patterned substrate.

2. The system of claim 1, further comprising one or more substrate-side lenses configured to focus the radiation from the radiation source onto the structure and to direct the diffracted and / or reflected radiation from the structure into the one or more multi-core waveguides.

3. The system of claim 2, wherein the one or more substrate-side lenses comprise a substrate-side microlens array.

4. The system of claim 3, wherein the number of lenses in the substrate-side microlens array corresponds to the number of fiber cores in the one or more multi-core waveguides.

5. The system of claim 4, wherein the length of the one or more multi-core waveguides is configured to facilitate the placement of the radiation source and / or the radiation sensor at spaced locations relative to the patterned substrate, in order to provide increased functional space for other components of the measurement system located near the patterned substrate, the other components including the substrate-side microlens array.

6. The system according to any one of claims 1 to 5, further comprising one or more source and sensor-side lenses, the one or more source and sensor-side lenses being configured to direct the radiation from the radiation source into the one or more multi-core waveguides and to direct the diffracted and / or reflected radiation from the substrate conducted through the one or more multi-core waveguides toward the radiation sensor.

7. The system of claim 6, wherein the one or more source and sensor-side lenses comprise a source and sensor-side microlens array.

8. The system of claim 7, wherein the number of lenses in the source and sensor-side microlens array corresponds to the number of fiber cores in the one or more multi-core waveguides.

9. The system according to any one of claims 1 to 8, wherein the spaced-out positions include a position away from the side of the patterned substrate, the side of the patterned substrate including the structure and the one or more layers.

10. The system according to any one of claims 1 to 9, wherein the length of the one or more multi-core waveguides is up to about 0.1 m, 0.25 m, 0.5 m, 1 m, or 10 m.

11. The system according to any one of claims 1 to 10, wherein the radiation source is configured to generate spatially incoherent and / or partially coherent radiation, and the radiation from the radiation source comprises multiple modes.

12. The system of claim 11, wherein the number of the plurality of modes corresponds to the number of fiber cores in the one or more multi-core waveguides.

13. The system of claim 12, wherein the number of fiber cores is the total number of fiber cores.

14. The system of claim 12, wherein when the one or more multi-core waveguides are in the Fourier and / or pupil planes with respect to the patterned substrate, the number of cores is a subset of the total number of cores.

15. The system according to any one of claims 1 to 14, wherein each fiber core in the one or more multi-core waveguides conducts radiation of a single spatial mode.

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