Systems and methods for sequential and parallel optical detection of alignment marks

Abstract

The sensor apparatus includes a sensor array and a metrology stage coupled to the sensor array. The sensor array includes a plurality of sensors. Each sensor in the sensor array is configured to illuminate a diffractive target on the substrate with radiation and detect a signal beam including diffraction order sub-beams reflected from the diffractive target. The metrology stage is configured to move the sensor array relative to the substrate. The sensor apparatus is configured to measure a plurality of diffractive targets on the substrate at a rate based on a density of the plurality of sensors relative to the plurality of diffractive targets.

Description

[Technical Field]

[0001] [CROSS REFERENCE TO RELATED APPLICATIONS] This application claims priority to U.S. Application No. 63 / 431,285, filed December 8, 2022, which is incorporated herein by reference in its entirety.

[0002] [Technical field] The present disclosure relates to sensor apparatus, systems and methods, for example for lithographic apparatus and systems. [Background technology]

[0003] A lithographic apparatus is a machine configured to apply a desired pattern onto a substrate. Lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs). A lithographic apparatus may, for example, project a pattern in a patterning device (e.g., mask, reticle) onto a layer of radiation-sensitive material (resist) provided on the substrate.

[0004] To project a pattern onto a substrate, a lithographic apparatus may use electromagnetic radiation. The wavelength of this radiation determines the minimum size of features that can be formed on the substrate. Lithographic apparatuses that use extreme ultraviolet (EUV) radiation, having a wavelength in the range of 4-20 nm (e.g., 6.7 nm or 13.5 nm), may be used to form smaller features on a substrate than lithographic apparatuses that use deep ultraviolet (DUV) radiation, having wavelengths of, for example, 157 nm, 193 nm, or 248 nm. Summary of the Invention [Problem to be solved by the invention]

[0005] To control a lithography process to accurately form device features on the substrate, one or more targets are provided on the substrate. Lithography apparatuses use one or more sensors to accurately measure characteristics of the targets. Existing alignment systems and techniques have certain drawbacks and limitations. For example, conventional systems utilize a single sensor head and are generally relatively slow and bulky. Furthermore, conventional sensors require significant time to move from one target to the next, resulting in the sensor spending most of its time idle during operation. In addition, there are limitations to the speed at which the sensor can translate from one target to the next and the required dwell time between measurements.

[0006] Because hundreds of sensors can be implemented in a sensor array on the same common platform, compact systems can increase accuracy, yield, cost-effectiveness, scalability, and reduce errors in the lithography process. Component integration can provide miniaturized sensor arrays for sequential or parallel measurement of specific properties of one or more targets on a substrate. Multiple targets on the same substrate can be interrogated simultaneously with the sensor array. Additionally, integrated optics can provide customized patterns for corresponding target geometries, enabling simultaneous measurement of all relevant targets on a substrate, increasing speed and accuracy.

[0007] Thus, there is a need to provide, for example, a reduced footprint and a scalable, compact sensor array, increase the accuracy and speed of measuring targets on a substrate, increase the number of targets that can be measured in a given time (e.g., at least 300 marks), increase the density of sensors relative to targets, reduce idle time, reduce errors in the lithography process, and increase manufacturing throughput and yield of the lithography process. [Means for solving the problem]

[0008] In some aspects, an apparatus includes a sensor array and a metrology stage coupled to the sensor array. In some aspects, the sensor array may include multiple sensors. In some aspects, each sensor of the sensor array may be configured to illuminate radiation onto a diffractive target on a substrate including multiple diffractive targets. In some aspects, each sensor of the sensor array may be further configured to detect a signal beam including diffraction order sub-beams reflected from the diffractive target. In some aspects, the metrology stage may be configured to move the sensor array relative to the substrate. In some aspects, the apparatus may be configured to measure multiple diffractive targets at a rate based on a density of the multiple sensors relative to the multiple diffractive targets.

[0009] In some aspects, an apparatus may be configured to measure a plurality of diffraction targets at a rate of at least 10 diffraction targets per second. In some aspects, an apparatus may be configured to measure a plurality of diffraction targets at a rate of at least 20 diffraction targets per second. In some aspects, an apparatus may be configured to measure a plurality of diffraction targets at a rate of at least 30 diffraction targets per second. In some aspects, an apparatus may be configured to measure a plurality of diffraction targets at a rate of at least 50 diffraction targets per second. In some aspects, an apparatus may be configured to measure a plurality of diffraction targets at a rate of at least 55 diffraction targets per second. In some aspects, an apparatus may be configured to measure a plurality of diffraction targets at a rate of at least 60 diffraction targets per second.

[0010] In some aspects, an apparatus may be configured to measure multiple diffraction targets at a rate of at least 100 ms per diffraction target. In some aspects, an apparatus may be configured to measure multiple diffraction targets at a rate of at least 50 ms per diffraction target. In some aspects, an apparatus may be configured to measure multiple diffraction targets at a rate of at least 30 ms per diffraction target. In some aspects, an apparatus may be configured to measure multiple diffraction targets at a rate of at least 20 ms per diffraction target. In some aspects, an apparatus may be configured to measure multiple diffraction targets at a rate of at least 18 ms per diffraction target. In some aspects, an apparatus may be configured to measure multiple diffraction targets at a rate of at least 15 ms per diffraction target.

[0011] In some aspects, the apparatus may be configured to reduce overlay errors based on detection of high spatial frequency deformations of the substrate.

[0012] In some aspects, the density of the plurality of sensors may be at least equal to the density of the plurality of diffraction targets. In some aspects, the density of the plurality of sensors may be at least 5 times the density of the plurality of diffraction targets. In some aspects, the density of the plurality of sensors may be at least 10 times the density of the plurality of diffraction targets. In some aspects, the density of the plurality of sensors may be at least 20 times the density of the plurality of diffraction targets. In some aspects, the density of the plurality of sensors may be at least 50 times the density of the plurality of diffraction targets. In some aspects, the density of the plurality of sensors may be at least 100 times the density of the plurality of diffraction targets.

[0013] In some aspects, the density of the plurality of diffraction targets may be at least two times the density of the plurality of sensors. In some aspects, the density of the plurality of diffraction targets may be at least five times the density of the plurality of sensors. In some aspects, the density of the plurality of diffraction targets may be at least ten times the density of the plurality of sensors. In some aspects, the density of the plurality of diffraction targets may be at least twenty times the density of the plurality of sensors. In some aspects, the density of the plurality of diffraction targets may be at least fifty times the density of the plurality of sensors. In some aspects, the density of the plurality of diffraction targets may be at least one hundred times the density of the plurality of sensors.

[0014] In some aspects, in a first mode, the apparatus may be configured to sequentially measure multiple diffraction targets. In some aspects, in the first mode, the metrology stage may move a first sensor of the sensor array over a first diffraction target of the multiple diffraction targets based on a minimum distance between the first sensor and the first diffraction target. In some aspects, the apparatus may be further configured to determine the minimum distance based on an optimization algorithm. In some aspects, the optimization algorithm may take into account relative distances between the multiple sensors and the multiple diffraction targets.

[0015] In some aspects, in the second mode, the apparatus can be configured to simultaneously measure multiple diffraction targets. In some aspects, in the second mode, the metrology stage can rotate at least first and second sensors of the sensor array over first and second diffraction targets of the multiple diffraction targets, respectively, based on a relative rotation angle between the sensor array and the substrate. In some aspects, the apparatus can be further configured to determine the relative rotation angle based on an optimization algorithm. In some aspects, the optimization algorithm can consider a relative rotation between the multiple sensors and the multiple diffraction targets in a range of 0 degrees to 45 degrees.

[0016] In some aspects, in the third mode, the apparatus can be configured to simultaneously measure multiple diffractive targets on the substrate. In some aspects, in the third mode, each sensor in the sensor array can have a field of view that overlaps with adjacent sensors.

[0017] In some aspects, each sensor of the sensor array can include an integrated optics chip. In some aspects, the integrated optics chip can include an illumination source configured to provide an illumination beam. In some aspects, the integrated optics chip can include an optical element configured to direct the illumination beam toward a diffractive target. In some aspects, the integrated optics chip can include a detector configured to detect the signal beam.

[0018] In some aspects, each sensor in the sensor array can include an integrated optical interconnect. In some aspects, the integrated optical interconnect can include an input waveguide configured to receive the illumination beam. In some aspects, the integrated optical interconnect can include an optical switch configured to direct the illumination beam to the diffractive target and receive the signal beam. In some aspects, the integrated optical interconnect can include an output waveguide configured to transmit the signal beam.

[0019] In some aspects, the apparatus can further include a detector system including a detector. In some aspects, the detector system can be configured to collect the signal beam.

[0020] In some aspects, the apparatus may further include a processor. In some aspects, the processor may be coupled to the sensor array, the metrology stage, and the detector system. In some aspects, the processor may be configured to measure a characteristic of the diffractive target based on the signal beam. In some aspects, the characteristic of the diffractive target may be an alignment position. In some aspects, the characteristic of the diffractive target may be an overlay error.

[0021] In some aspects, the sensor array can overfill the surface area of ​​the substrate. In some aspects, the sensor array can underfill the surface area of ​​the substrate.

[0022] In some aspects, the detection system may include a sensor array, a metrology stage, and an optical coupler. In some aspects, the sensor array may include multiple sensors disposed on multiple diffraction targets on the substrate. In some aspects, each sensor of the sensor array may be configured to illuminate a diffraction target of the multiple diffraction targets with radiation. In some aspects, each sensor of the sensor array may be configured to detect a signal beam including diffraction order sub-beams reflected from the diffraction target. In some aspects, a metrology stage may be coupled to the sensor array. In some aspects, the metrology stage may be configured to move the sensor array relative to the substrate. In some aspects, an optical coupler may be between the sensor array and the metrology stage. In some aspects, the sensor array may include the optical coupler. In some aspects, the metrology stage may include the optical coupler. In some aspects, the optical coupler may include multiple waveguides optically coupled to the multiple sensors. In some aspects, the optical coupler may be configured to route the signal beam from each sensor to multiple fixed optical ports.

[0023] In some aspects, the detection system can include multiple optical couplers, each having multiple sensors positioned at predetermined locations.

[0024] In some aspects, a lithographic apparatus may include an illumination system, a projection system, and a sensor apparatus. In some aspects, the illumination system may be configured to illuminate a patterning device. In some aspects, the projection system may be configured to project an image of the patterning device onto a substrate. In some aspects, the sensor apparatus may be configured to measure an overlay error of the lithographic apparatus. In some aspects, the sensor apparatus may include a sensor array including a plurality of sensors and a metrology stage. In some aspects, each sensor of the sensor array may be configured to illuminate a diffraction target on a substrate including a plurality of diffraction targets with radiation. In some aspects, each sensor of the sensor array may be configured to detect a signal beam including diffraction order sub-beams reflected from the diffraction target. In some aspects, a metrology stage may be coupled to the sensor array and configured to move the sensor array relative to the substrate. In some aspects, the sensor apparatus may be configured to measure the plurality of diffraction targets at a rate based on a density of the plurality of sensors for the plurality of diffraction targets.

[0025] In some aspects, the sensor device may be configured to measure the plurality of diffraction targets at a rate of at least 10 diffraction targets per second. In some aspects, the sensor device may be configured to measure the plurality of diffraction targets at a rate of at least 20 diffraction targets per second. In some aspects, the sensor device may be configured to measure the plurality of diffraction targets at a rate of at least 30 diffraction targets per second. In some aspects, the sensor device may be configured to measure the plurality of diffraction targets at a rate of at least 50 diffraction targets per second. In some aspects, the sensor device may be configured to measure the plurality of diffraction targets at a rate of at least 100 diffraction targets per second.

[0026] In some aspects, the sensor device may be configured to measure the plurality of diffraction targets at a rate of at least 100 ms per diffraction target. In some aspects, the sensor device may be configured to measure the plurality of diffraction targets at a rate of at least 50 ms per diffraction target. In some aspects, the sensor device may be configured to measure the plurality of diffraction targets at a rate of at least 20 ms per diffraction target. In some aspects, the sensor device may be configured to measure the plurality of diffraction targets at a rate of at least 10 ms per diffraction target.

[0027] In some aspects, the lithographic apparatus may be configured to reduce overlay errors based on detection of high spatial frequency deformations of the substrate.

[0028] In some aspects, a method for measuring multiple diffractive targets on a substrate may include measuring a signal beam from multiple diffractive targets on the substrate with a sensor device. In some aspects, the sensor device may include a sensor array and a metrology stage coupled to the sensor array. In some aspects, each sensor of the sensor array may be configured to illuminate a diffractive target on the substrate with radiation and detect a signal beam including diffraction order sub-beams reflected from the diffractive target. In some aspects, the metrology stage may be configured to move the sensor array relative to the substrate. In some aspects, the sensor device may be configured to measure the multiple diffractive targets at a rate based on a density of the multiple sensors relative to the multiple diffractive targets.

[0029] In some aspects, the measuring can include sequentially measuring a plurality of diffraction targets, hi some aspects, the sequential measuring can include translating a first sensor of the sensor array over a first diffraction target of the plurality of diffraction targets based on a minimum distance between the first sensor and the first diffraction target.

[0030] In some aspects, the measuring can include simultaneously measuring multiple diffractive targets. In some aspects, the simultaneously measuring can include rotating at least first and second sensors of the sensor array over first and second diffractive targets of the multiple diffractive targets, respectively, based on a relative rotation angle between the sensor array and the substrate. In some aspects, the simultaneously measuring can include overlapping a field of view of each sensor of the sensor array with adjacent sensors.

[0031] In some aspects, simultaneously measuring can include positioning multiple sensors at predetermined locations on each of the multiple diffractive targets. In some aspects, simultaneously measuring can include detecting a signal beam from each of the multiple sensors through an optical coupler. In some aspects, the optical coupler can include multiple waveguides. In some aspects, the multiple waveguides can be optically coupled to the multiple sensors and the multiple fixed optical ports.

[0032] In some aspects, the method may further include replacing the sensor array and optical coupler with a second sensor array and second optical coupler configured to measure a plurality of diffractive targets on a second substrate.

[0033] Implementations of any of the above-described techniques may include EUV light sources, DUV light sources, systems, methods, processes, devices, and / or apparatus. Details of one or more implementations are set forth in the accompanying drawings and the description below. Other features will be apparent from the description, drawings, and claims.

[0034] Further features and exemplary aspects of the aspects, as well as the structure and operation of various aspects, are described in detail below with reference to the accompanying drawings. It should be noted that the aspects are not limited to the specific aspects described herein. Such aspects are presented here for illustrative purposes only. Additional aspects will be apparent to those skilled in the art based on the teachings contained herein. [Brief explanation of the drawings]

[0035] The accompanying drawings, which are incorporated herein and constitute a part of the specification, illustrate aspects and, together with the description, further serve to explain the principles of the aspects and to enable one skilled in the art to make and use the aspects.

[0036] FIG. 1 is a schematic diagram of a lithographic apparatus according to an example aspect.

[0037] FIG. 2A is a schematic side view of an integrated optical chip, according to an example aspect.

[0038] FIG. 2B is a schematic top view of the integrated optical chip shown in FIG. 2A.

[0039] FIG. 3 is a schematic top view of a substrate table for a substrate according to an example aspect.

[0040] FIG. 4 is a schematic plan view of a substrate having multiple diffractive targets, according to an example aspect.

[0041] FIG. 5 is a schematic side view of a sensor device having a sensor array, according to an example aspect.

[0042] FIG. 6 is a schematic plan view of the sensor device shown in FIG.

[0043] FIG. 7 is a schematic plan view of the sensor apparatus shown in FIG. 5 in a first mode, according to an exemplary aspect.

[0044] FIG. 8 is a schematic plan view of the sensor apparatus shown in FIG. 5 in a second mode, according to an exemplary aspect.

[0045] FIG. 9 is a schematic side view of the sensor apparatus shown in FIG. 5 in a third mode with overlapping sensor arrays, according to an example aspect.

[0046] FIG. 10 is a schematic plan view of the sensor device shown in FIG.

[0047] FIG. 11 is a schematic plan view of the sensor device shown in FIG. 5 having a congruent sensor array, according to an exemplary aspect.

[0048] FIG. 12 is a schematic plan view of the sensor device shown in FIG. 5 with an underfilled sensor array, according to an exemplary aspect.

[0049] FIG. 13 is a schematic plan view of the sensor device shown in FIG. 5 having a high-density sensor array, according to an exemplary aspect.

[0050] FIG. 14 is a schematic plan view of the sensor device shown in FIG. 13 in a fourth mode, according to an exemplary aspect.

[0051] FIG. 15 is a schematic side view of a sensor device with integrated optical elements, according to an example aspect.

[0052] FIG. 16 is a schematic top view of the sensor device shown in FIG.

[0053] FIG. 16A is a schematic plan view of a sensor having an optical switch, according to an exemplary aspect.

[0054] FIG. 16B is a schematic plan view of a sensor having an optical switch, according to an exemplary aspect.

[0055] FIG. 17 is a schematic side view of a sensor apparatus having an optical coupler, according to an example aspect.

[0056] FIG. 18 is a schematic top view of the sensor device shown in FIG.

[0057] Aspect features and exemplary aspects will become more apparent from the following detailed description taken in conjunction with the drawings, in which like reference symbols represent corresponding elements throughout. Like reference numbers in the drawings generally indicate identical, functionally similar, and / or structurally similar elements. Additionally, the left-most digit(s) of a reference number generally identifies the figure in which that reference number first appears. Unless otherwise noted, the drawings provided throughout the disclosure should not be construed as drawn to scale. DETAILED DESCRIPTION OF THE INVENTION

[0058] This specification discloses one or more aspects incorporating the features of this invention. The disclosed aspects are merely exemplary of the invention. The scope of the invention is not limited to the disclosed aspects. The invention is defined by the claims appended hereto.

[0059] References to a described aspect, or to "one aspect," "one aspect," "an example aspect," "an exemplary aspect," or the like in the specification, indicate that the described aspect may include a particular feature, structure, or characteristic, but that not all aspects necessarily include the particular feature, structure, or characteristic. Moreover, such phrases do not necessarily refer to the same aspect. Furthermore, when a particular feature, structure, or characteristic is described with respect to one aspect, it is understood that it is within the knowledge of one of ordinary skill in the art to enable such feature, structure, or characteristic with respect to other aspects, whether or not explicitly stated.

[0060] Spatially relative terms such as "beneath" (e.g., below, lower) and "on" (e.g., above, on, upper) may be used herein to facilitate describing the relationship of one illustrated element or feature to another. Spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation shown. The device may be oriented in different ways (rotated 90 degrees or at other orientations) and the spatially relative terms used herein may be interpreted accordingly.

[0061] As used herein, the terms "approximately," "substantially," or "about" refer to a given quantity value that can vary based on the particular technique. Based on the particular technique, the terms "approximately," "substantially," or "about" can refer to a given quantity value that varies within, for example, 1-15% of the value (e.g., ±1%, ±2%, ±5%, ±10%, or ±15% of the value).

[0062] Aspects of the present disclosure may be implemented as hardware, firmware, software, or any combination thereof. Aspects of the present disclosure may also be implemented as instructions stored on a machine-readable medium, which may be read and executed by one or more processors. A machine-readable medium may include any mechanism for storing or transmitting information in a manner readable by an apparatus (e.g., a computing device). For example, a machine-readable medium may include read-only memory (ROM), random-access memory (RAM), magnetic disk storage media, optical storage media, flash memory devices, electrical, optical, acoustic, or other forms of transmission signals (e.g., carrier waves, infrared signals, digital signals, etc.), etc. Furthermore, firmware, software, routines, and / or instructions may be described herein as performing particular actions. However, it should be understood that such description is merely for convenience, and that such actions are actually caused by a computing device, processor, controller, or other device executing the firmware, software, routines, instructions, etc.

[0063] Before describing such aspects in more detail, example environments in which aspects of the present disclosure may be implemented are presented for reference.

[0064] Exemplary Lithography System

[0065] 1 shows a lithography system comprising a radiation source SO and a lithographic apparatus LA. The radiation source SO is configured to generate a beam of EUV and / or DUV radiation B and to provide the beam of EUV and / or DUV radiation B to the lithographic apparatus LA. The lithographic apparatus LA comprises an illumination system IL, a support structure MT (e.g., a mask table, reticle table, reticle stage) configured to support a patterning device MA (e.g., a mask, a reticle), a projection system PS, and a substrate table WT configured to support a substrate W.

[0066] The illumination system IL is configured to condition the EUV and / or DUV radiation beam B before it is incident on the patterning device MA. In addition, the illumination system IL may include a facetted field mirror device 10 and a facetted pupil mirror device 11. The facetted field mirror device 10 and facetted pupil mirror device 11 together provide the EUV and / or DUV radiation beam B with a desired cross-sectional shape and a desired intensity distribution. The illumination system IL may include other mirrors or devices in addition to or instead of the facetted field mirror device 10 and facetted pupil mirror device 11.

[0067] After being so conditioned, the EUV and / or DUV radiation beam B interacts with the patterning device MA. This interaction may be reflective (as shown), which may be preferable for EUV radiation. As a result of this interaction, a patterned EUV and / or DUV radiation beam B' is produced. The projection system PS is configured to project the patterned EUV and / or DUV radiation beam B' onto a substrate W. To that end, the projection system PS may comprise a plurality of mirrors 13, 14 configured to project the patterned EUV and / or DUV radiation beam B' onto the substrate W held by a substrate table WT. The projection system PS may apply a reduction factor to the patterned EUV and / or DUV radiation beam B' to form an image having smaller features than corresponding features on the patterning device MA. For example, a reduction factor of 4 or 8 may be applied. Although the projection system PS is illustrated in FIG. 1 as having only two mirrors 13, 14, the projection system PS may include a different number of mirrors (e.g., six or eight mirrors).

[0068] The substrate W may include a previously formed pattern, in which case the lithographic apparatus LA aligns the image formed by the patterned EUV and / or DUV radiation beam B' with the previously formed pattern on the substrate W.

[0069] Exemplary Integrated Optical Chip

[0070] Compact direct measurement sensor systems offer improved accuracy, cost-effectiveness, and scalability. For example, compact sensors on the order of approximately 10 mm x 10 mm implemented on the same common platform can form a sensor array of hundreds of sensors. These miniaturized sensors (e.g., 10 mm x 10 mm) can measure specific characteristics (e.g., alignment position) of alignment marks on a substrate. Integration of components (e.g., illumination sources, fibers, mirrors, lenses, waveguides, detectors, processors, etc.) in a single "on-chip" sensor can also improve miniaturization. Additionally, multiple alignment marks on the same substrate can be interrogated by multiple sensors (e.g., a sensor array), and different measurements can be performed simultaneously or in real time.

[0071] 2A and 2B illustrate an integrated optics chip 200 according to an example aspect. The integrated optics chip 200 may be configured to measure characteristics (e.g., alignment position, overlay, etc.) of a diffraction target 204 on a substrate 202 to reduce errors (e.g., alignment, overlay) in a lithography process (e.g., in a lithography apparatus LA). Although the integrated optics chip 200 is shown in FIGS. 2A and 2B as a standalone apparatus and / or system, aspects of the present disclosure may be used in conjunction with other apparatus, systems, and / or methods (e.g., a lithography apparatus LA, a substrate table 300, a substrate to be patterned 400, a substrate to be patterned 400′, a sensor apparatus 500, a sensor apparatus 500′, and / or a sensor apparatus 500″).

[0072] 2A , the integrated optical chip 200 may include an illumination system 220, a detector system 270, and / or a processor 298. The illumination system 220 may be configured to send an illumination beam 226 along an illumination path 232 toward the diffractive target 204. In some aspects, the illumination system 220 may provide structured illumination to form a fringe pattern 242 (e.g., a Moiré pattern) configured to serve as a projected reference grating for investigating asymmetries in the diffractive target 204 by utilizing the Moiré effect. The Moiré effect is a large-scale interference effect that occurs when an opaque pattern (e.g., parallel lines) with transparent gaps is overlaid on another similar pattern.

[0073] 2B , illumination system 220 may include illumination source 222 (e.g., coherent), illumination coupling 224, illumination beam 226, first off-axis illumination beam 228, second off-axis illumination beam 230, illumination path 232, first angle of incidence 238, second angle of incidence 240, and / or adjustable optical element 250. Illumination source 222 may generate illumination beam 226 and may be coupled to illumination coupling 224 by, for example, a fiber optic port or a waveguide. In some aspects, illumination system 220 may include one or more waveguides or gratings for coupling illumination beam 226 to diffractive target 204.

[0074] In some aspects, the illumination system 220 may be configured to provide a coherent electromagnetic broadband illumination beam 226 having one or more passbands. For example, the one or more passbands may be in a spectrum of wavelengths between about 500 nm and about 2000 nm. In some aspects, the illumination system 220 may be further configured to provide one or more passbands having a substantially constant center wavelength (CWL) value over time (e.g., over the lifetime of the illumination system 220).

[0075] As shown in FIG. 2B , the illumination coupling 224 can direct the illumination beam 226 along an illumination path 232 toward the diffractive target 204. The illumination coupling 224 (e.g., a waveguide) splits the illumination beam 226 from the illumination source 222 into a first off-axis illumination beam 228 and a second off-axis illumination beam 230. The illumination path 232 can include, for example, a first illumination path 232 a and a second illumination path 232 b, as shown in FIG. 2B . The first off-axis illumination beam 228 can be directed along the first illumination path 232 a toward the diffractive target 204. The second off-axis illumination beam 230 can be directed along the second illumination path 232 b toward the diffractive target 204. The first and second off-axis illumination beams 228, 230 (e.g., coherent) can be directed toward a diffractive target 204 on a substrate 202 disposed near the illumination system 220.

[0076] 2A and 2B, for example, first and second off-axis illumination beams 228, 230 (e.g., coherent) can generate a fringe pattern 242 on the diffractive target 204. The first off-axis illumination beam 228 can be directed at a first angle of incidence 238 relative to the diffractive target 204, and the second off-axis illumination beam 230 can be directed at a second angle of incidence 240 relative to the diffractive target 204. In some aspects, the first and second off-axis illumination beams 228, 230 (e.g., coherent) can overlap and interfere to form structured illumination, fringe pattern 242, because the beams are coherent. The fringe pattern 242 (e.g., a Moiré pattern) can function as a reference grating that is projected onto the diffractive target 204.

[0077] The adjustable optical element 250 may be configured to direct the first and second off-axis illumination beams 228, 230 toward the diffractive target 204 on the substrate 202. In some aspects, the adjustable optical element 250 may adjust the first and second angles of incidence 238, 240, respectively, to adjust the periodicity of the fringe pattern 242. For example, the periodicity of the fringe pattern 242 may be proportional to the first and second angles of incidence 238, 240. In some aspects, the adjustable optical element 250 may be configured to match the periodicity of the diffractive target 204 with the periodicity of the fringe pattern 242 by adjusting the first and second angles of incidence 238, 240 to change the periodicity of the fringe pattern 242. For example, when the periodicity of the fringe pattern 242 is aligned (eg, matches) with the periodicity of the diffractive target 204 , aberrations in the integrated optic chip 200 do not alter the signal beam 290 detected by the detector system 270 .

[0078] The adjustable optical element 250 may include any optical element (e.g., a mirror, a lens, a prism, a waveguide, an optical modulator, etc.). In some aspects, the adjustable optical element 250 may be capable of varying the first and second angles of incidence 238, 240 of the first and second off-axis illumination beams 228, 230. For example, as shown in FIG. 2B , the adjustable optical element 250 may include an adjustable prism mirror 252 and first and second off-axis mirrors 256, 258.

[0079] 2B , the adjustable optical element 250 can include an adjustable prism mirror 252, a first off-axis mirror 256, and a second off-axis mirror 258. The adjustable prism mirror 252 can be configured to adjust the positions of the first and second off-axis illumination beams 228, 230 by adjusting the position of the adjustable prism mirror 252 relative to the illumination beam 226. For example, the adjustable prism mirror 252 can be translated toward or away from the illumination coupling 224, or rotated or tilted relative to the illumination coupling 224 to change the spot positions of the first and second coherent off-axis illumination beams 228, 230 on the first and second off-axis mirrors 256, 258, respectively. In some aspects, by adjusting the position of the adjustable prism mirror 252 relative to the illumination beam 226, the first and second angles of incidence 238, 240 of the first and second off-axis illumination beams 228, 230, respectively, can be varied to proportionally change the periodicity of the fringe pattern 242. In some aspects, the adjustable prism mirror 252 can be adjusted (e.g., translated, rotated, tilted, etc.) to adjust the periodicity of the fringe pattern 242 to match the periodicity of the diffractive target 204. In some aspects, the first and second off-axis mirrors 256, 258 can be fixed and configured to reflect the first and second off-axis illumination beams 228, 230, respectively, toward the diffractive target 204.

[0080] In some aspects, the adjustable prism mirror 252 may include microelectromechanical systems (MEMS)-based actuators configured to adjust the first and second illumination paths 232a, 232b and the first and second angles of incidence 238, 240 of the first and second off-axis illumination beams 228, 230, respectively. For example, the MEMS-based actuators of the adjustable prism mirror 252 may control the focal points of the first and second off-axis illumination beams 228, 230 on the diffractive target 204. In some aspects, the first and / or second off-axis mirrors 256, 258 may be flat, tilted, parabolic, or elliptical mirrors. For example, as shown in FIG. 2B , the first and second off-axis mirrors 256, 258 may be parabolic. In some aspects, the first and / or second off-axis mirrors 256, 258 may be adjustable. For example, the first and / or second off-axis mirrors 256, 258 may each include a MEMS-based actuator.

[0081] In some aspects, the first angle of incidence 238 and the second angle of incidence 240 may be the same. In some aspects, the first and second off-axis illumination beams 228, 230 may be focused beams on the diffractive target 204. For example, the adjustable optical element 250 may include focusing optics (e.g., first and second off-axis mirrors 256, 258 optimized for a focal length of about 1 mm or less). In some aspects, the first and second coherent off-axis illumination beams 228, 230 may be defocused beams on the diffractive target 204.

[0082] First and second off-axis illumination beams 228, 230 from the illumination source 222 can be transmitted toward a diffractive target 204 on a substrate 202 positioned near the illumination system 220 to generate a signal beam 290. The signal beam 290 can include diffraction order sub-beams diffracted from the diffractive target 204. For example, as shown in FIGS. 2A and 2B, the signal beam 290 can include a first diffraction order sub-beam 292, a second diffraction order sub-beam 294, and a third diffraction order sub-beam 296.

[0083] In some aspects, first diffraction order sub-beam 292 may be a negative diffraction order (e.g., −1) sub-beam, second diffraction order sub-beam 294 may be a positive diffraction order (e.g., +1) sub-beam, and third diffraction order sub-beam 296 may be a zero diffraction order (e.g., 0) sub-beam. As shown in Figures 2A and 2B, first, second, and third diffraction order sub-beams 292, 294, 296 may be directed toward detector system 270 (e.g., toward fixed optical element 216 and detector 218).

[0084] Detector system 270 may be configured to collect signal beam 290. As shown in FIGS. 2A and 2B, detector system 270 may include fixed optical element 216 and detector 218. Fixed optical element 216 may be configured to collect signal beam 290 and direct signal beam 290 to detector 218. Detector 218 may be configured to detect first, second, and / or third diffraction order sub-beams 292, 294, 296 of signal beam 290. In some aspects, fixed optical element 216 may be a low numerical aperture (NA) lens. For example, fixed optical element 216 may have an NA of about 0.1 to about 0.4. In some aspects, fixed optical element 216 may be an achromatic lens. For example, fixed optical element 216 may be an achromatic doublet. In some aspects, detector system 270 may be configured to measure a characteristic of diffractive target 204 based on signal beam 290. In some aspects, the property of the diffraction target 204 measured by the detector system 270 is alignment position. In some aspects, the property of the diffraction target 204 measured by the detector system 270 is overlay. In some aspects, the detector 218 may be a photodetector, a photodiode, a charge-coupled device (CCD), an avalanche photodiode (APD), a camera, a PIN detector, a multimode fiber, a single-mode fiber, or any other suitable photodetector.

[0085] In some aspects, the diffraction target 204 may be an alignment mark. In some aspects, the substrate 202 may be supported by a stage and aligned along an alignment axis. In some aspects, the diffraction target 204 on the substrate 202 may be a 1D grating that is printed such that after development, the bars are formed of solid resist lines. In some aspects, the diffraction target 204 may be a 2D array or grating that is printed such that after development, the grating is formed of solid resist pillars or vias in the resist. For example, the bars, pillars, or vias may instead be etched into the substrate 202.

[0086] The processor 298 may be configured to measure characteristics of the diffractive target 204 based on the signal beam 290. In some aspects, the processor 298 may be integrated with the detector system 270, the illumination system 220, or may be external to the detector system 270 and the illumination system 220. For example, as shown in FIG. 2A , the processor 298 may be disposed on top of the illumination system 220. As shown in FIG. 2A , the processor 298 may include a first control signal 299 a and / or a second control signal 299 b. The first control signal 299 a may be configured to send and receive data between the illumination source 222 and the processor 298. The second control signal 299 b may be configured to send and receive data between the detector 218 and the processor 298. The processor 298 may be coupled to the illumination system 220 via the first control signal 299 a. The processor 298 may be coupled to the detector system 270 via the second control signal 299 b. In some aspects, the control signals 299a, 299b may be coupled to the illumination system 220 and / or the detector system 270 via optical fibers.

[0087] In some aspects, the processor 298 may be configured to measure a property of the diffractive target 204 based on the signal beam 290. For example, the property of the diffractive target 204 measured by the processor 298 may be an alignment position or an overlay.

[0088] 2A, processor 298 may be integrated onto illumination system 220. In some aspects, processor 298 may be external to detector system 270 and may be coupled to detector system 270 by, for example, a fiber optic cable. In some aspects, processor 298 may be external to illumination system 220 and may be coupled to illumination system 220 by, for example, a fiber optic cable.

[0089] In some aspects, the illumination system 220 and the detector system 270 may be separated by a displacement angle 212. For example, the displacement angle 212 may be configured to be between about 1 degree and about 5 degrees. As shown in FIG. 2A , the displacement angle 212 may include a first displacement angle 212a between the illumination system 220 and an axis perpendicular to the diffraction target 204 and a second displacement angle 212b between the detector system 270 and an axis perpendicular to the diffraction target 204. In some aspects, the first and second displacement angles 212a, 212b are equal. In some aspects, the integrated optical chip 200 may be configured to be a compact system. In some aspects, as shown in FIG. 2 , the elongated area 214 of the integrated optical chip 200 may be about 10 mm x 10 mm. In some aspects, the elongated area 214 of the integrated optical chip 200 may be about 20 mm x 20 mm.

[0090] Exemplary substrate table and substrate to be patterned

[0091] 3 and 4 illustrate a substrate table 300 and a substrate 400 to be patterned according to example aspects. The substrate table 300 may be configured to measure characteristics (e.g., alignment position, pitch, diffraction order, depth, sub-segmentation, etc.) of one or more diffraction targets 404 on a substrate 402 of the substrate 400 to be patterned, for example, to improve alignment and calibration (e.g., shift-between-orders (SBO) calibration) in a lithography apparatus LA. Although the substrate table 300 is shown in FIG. 3 as a standalone apparatus and / or system, aspects of the present disclosure may be used in conjunction with other apparatus, systems, and / or methods (e.g., a lithography apparatus LA, a substrate table WT, an integrated optical chip 200, a substrate 400 to be patterned, a substrate 400′ to be patterned, a sensor apparatus 500, a sensor apparatus 500′, and / or a sensor apparatus 500″).

[0092] 3 , the substrate table 300 may include a plate 302 configured to support a substrate 400 to be patterned. The plate 302 may include a first alignment mark 310, a second alignment mark 312, a third alignment mark 320, and / or a fourth alignment mark 322. In some aspects, for example, the first alignment mark 310 may include a position alignment mark. In some aspects, for example, the second alignment mark 312 may include a pitch alignment mark. In some aspects, for example, the third alignment mark 320 may include a sub-segmentation alignment mark. In some aspects, for example, the fourth alignment mark 322 may include a depth alignment mark. In some aspects, the first, second, third, and fourth alignment marks 310, 312, 320, and 322 may include transmission sensor image (TIS) marks, integrated lens interferometer at scanner (ILIAS) marks, parallel integrated lens interferometer at scanner (PARIS) marks, and / or some combination thereof.

[0093] In some aspects, calibration (e.g., SBO calibration) of the substrate 400 to be patterned may be performed by measuring differences between the diffraction target 404 and the first, second, third, and / or fourth alignment marks 310, 312, 320, 322. For example, the measured positions (e.g., absolute positions, relative positions, pitch, diffraction orders, sub-segmentation, depth, etc.) of the first, second, third, and / or fourth alignment marks 310, 312, 320, 322 may be compared to the measured positions (e.g., absolute positions, relative positions, pitch, diffraction orders, sub-segmentation, depth, etc.) of the diffraction target 404, and errors may be determined and calibrated, for example, by a processor (not shown), a sensor device (not shown), and / or the lithography apparatus LA.

[0094] FIG. 4 illustrates a patterned substrate 400 according to an example aspect. The patterned substrate 400 may be configured to be patterned by a patterning device (e.g., a reticle), for example, in a lithography process in a lithography apparatus LA. The patterned substrate 400 may be configured to have one or more diffraction targets for calibration (e.g., alignment, overlay). Although the patterned substrate 400 is shown in FIG. 4 as a standalone apparatus and / or system, aspects of the present disclosure may be used in conjunction with other apparatus, systems, and / or methods (e.g., lithography apparatus LA, integrated optical chip 200, substrate table 300, patterned substrate 400′, sensor apparatus 500, sensor apparatus 500′, and / or sensor apparatus 500″).

[0095] As shown in FIG. 4, the substrate 400 to be patterned may include a substrate 402 and diffraction targets 404a-404g. In some aspects, the substrate 402 may be a wafer. For example, the wafer may have a diameter of 100 mm, 200 mm, 300 mm, and / or 450 mm. In some aspects, the substrate 402 may include any suitable material having a predetermined crystal orientation, including, but not limited to, silicon, germanium, and III-V semiconductors. The diffraction targets 404a-404g may be configured to calibrate (e.g., align) the substrate 400 to be patterned with respect to, for example, a lithography apparatus (e.g., lithography apparatus LA). In some aspects, the diffraction targets 404a-404g may include alignment marks, overlay marks, and / or combinations thereof. In some aspects, the diffraction targets 404a-404g may include TIS marks, ILIAS marks, PARIS marks, and / or some combination thereof. In some aspects, the diffraction targets 404a-404g may be symmetrically arranged on the substrate 402. In some aspects, as shown in FIG. 4, the diffraction targets 404a-404g may be asymmetrically arranged (e.g., randomly, custom, etc.) on the substrate 402. In some aspects, the substrate 400 to be patterned may be positioned on the plate 302. In some aspects, the plate 302 may be positioned on the substrate 400 to be patterned. In some aspects, the substrate 400 to be patterned may be positioned near the plate 302.

[0096] Exemplary Sensor Device

[0097] As described above, one or more diffractive targets (e.g., alignment marks, overlay marks) are provided on the substrate to control the lithographic process so as to accurately form device features on the substrate. The lithographic apparatus uses one or more sensors (e.g., alignment sensors, overlay sensors, and / or a combination of both) to accurately measure properties (e.g., position, overlay) of the diffractive targets.

[0098] Existing alignment systems and techniques have certain drawbacks and limitations. For example, conventional systems utilize a single sensor head and are generally relatively slow and bulky. Furthermore, conventional sensors require significant time to move from one target to the next, causing the sensor to spend most of its time in operation (e.g., approximately 85% of the time per measurement in an idle state). In addition, there are limitations to the speed at which the sensor can translate from one target to the next (e.g., approximately 3 m / s) and the required dwell time per measurement (e.g., approximately 10 ms). The dwell time is highly dependent on the size of the sensor.

[0099] Because hundreds of sensors can be implemented in a sensor array on the same common platform, compact systems can increase accuracy, yield, cost-effectiveness, scalability, and reduce errors in the lithography process. Integration of components (e.g., illumination sources, fibers, lenses, waveguides, detectors, processors, etc.) can provide miniaturized sensor arrays for sequential or parallel measurement of specific characteristics (e.g., alignment, overlay) of one or more diffraction targets on a substrate. Multiple diffraction targets on the same substrate can be simultaneously interrogated with a single sensor array (e.g., 5x5 array, 10x10 array, 25x25 array, 50x50 array, 100x100 array, 500x500 array, 1,000x1,000 array, etc.). In addition, integrated optics can provide customized patterns (e.g., optically coupled waveguides) for corresponding diffraction target geometries (e.g., different field sizes), enabling simultaneous measurement of all relevant diffraction targets on a substrate, enhancing speed and accuracy.

[0100] Aspects of the sensor devices, systems, and methods described below can provide reduced footprints and scalable, compact sensor arrays, increase the accuracy and speed of measuring diffractive targets on a substrate, increase the number of diffractive targets that can be measured in a given time (e.g., at least 300 targets), increase the density of sensors relative to diffractive targets, reduce idle time, reduce errors in the lithography process, and increase manufacturing throughput and yield of the lithography process.

[0101] 5-14 illustrate a sensor apparatus 500 according to various exemplary aspects. The sensor apparatus 500 may be configured to illuminate diffraction targets 404a-404g on a substrate 400 to be patterned and detect signal beams 546a-546i including diffraction order sub-beams reflected from the diffraction targets 404a-404g. The sensor apparatus 500 may be further configured to measure the diffraction targets 404a-404g sequentially. The sensor apparatus 500 may be further configured to measure the diffraction targets 404a-404g in parallel (simultaneously). The sensor apparatus 500 may be further configured to increase the rate at which the diffraction targets 404a-404b on the substrate 400 to be patterned are measured (e.g., at least 30 targets per second). The sensor apparatus 500 may be further configured to reduce idle time and increase the number of diffraction targets 404a-404g that can be measured in a given time (e.g., at least 300 targets at 50 targets per second). The sensor apparatus 500 may be further configured to increase the density of sensors 540a-540i relative to the diffraction targets 404a-404g (e.g., by at least a factor of 10). Although the sensor apparatus 500' is shown in FIGS. 5-14 as a standalone apparatus and / or system, aspects of the present disclosure may be used in conjunction with other apparatus, systems, and / or methods (e.g., lithography apparatus LA, integrated optical chip 200, substrate table 300, substrate to be patterned 400, substrate to be patterned 400', sensor apparatus 500', and / or sensor apparatus 500'').

[0102] 5 and 6, the sensor apparatus 500 may include a metrology stage 510, a processor 520, and a sensor array 530. The metrology stage 510 may be coupled to the sensor array 530 and configured to move (e.g., translate, rotate, and / or focus) the sensor array 530 relative to the substrate 400 being patterned. The metrology stage 510 may further be configured to receive and process signal beams 546a-546i from the sensor array 530. As shown in FIG. 5, the metrology stage 510 may include a mechanical coupling 512, optical ports 514a-514i, a linear actuator 516, a rotary actuator 518, and / or a processor 520.

[0103] The mechanical coupling 512 may be configured to support the sensor array 530 over the substrate 400 to be patterned and to couple the sensor array 530 to the metrology stage 510. In some aspects, the mechanical coupling 512 may include one or more electrical connections (e.g., ports) for providing electrical signals (e.g., power, data, etc.) to and from the sensor array (e.g., via the processor 520). In some aspects, the mechanical coupling 512 may be omitted and the sensor array 530 may be directly coupled to the metrology stage 510.

[0104] The optical ports 514a-514i may be configured to transmit and / or receive one or more optical signals (e.g., illumination beams 544a-i, signal beams 546a-546i) to and / or from the sensor array 530 (e.g., via the processor 520). In some aspects, the optical ports 514a-514i may be fixed (positioned) on the metrology stage 510. In some aspects, the optical ports 514a-514i may provide illumination beams 544a-544i, respectively, to sensors 540a-540i of the sensor array 530. In some aspects, the optical ports 514a-514i may receive signal beams 546a-546i, respectively, from sensors 540a-540i of the sensor array 530. In some aspects, the optical ports 514a-514i may include one or more detectors coupled to the processor 520. For example, the optical ports 514a-514i may be optical detectors (e.g., similar to the detector system 270 having the detector 218 shown in FIGS. 2A and 2B). In some aspects, the optical ports 514a-514i may include one or more waveguides for optically coupling to the sensors 540a-540i of the sensor array 530. In some aspects, the optical ports 514a-514i may be part of a detector system (e.g., coupled to the processor 520) configured to collect the signal beams 546a-546i from the sensor array 530. For example, the optical ports 514a-514i may be coupled to one or more detectors in the metrology stage 510 (e.g., similar to the detector system 270 shown in FIGS. 2A and 2B).

[0105] The linear actuator 516 may be configured to move (e.g., translate and / or focus) the sensor array 530 relative to the substrate 400 being patterned. In some aspects, the linear actuator 516 may move the sensor array 530 in three dimensions (X, Y, and Z) relative to the substrate 400 being patterned. In some aspects, the linear actuator 516 may include a motor, stepper, servo motor, or any other suitable actuator capable of translating in three dimensions (X, Y, and Z). In some aspects, the linear actuator 516 may be controlled by the processor 520, for example, to translate (e.g., X, Y) and / or focus (e.g., Z) one or more sensors 540 a- 540 i of the sensor array 530 relative to a corresponding one or more diffraction targets 404 a- 404 g on the substrate 400 being patterned. 7, in a first mode 10, the metrology stage 510 can translate the sensor array 530 (e.g., in the X and Y axes) relative to the substrate 400 being patterned such that the sensor center 542b of the sensor 540b is aligned on the diffraction target 404c. For example, as shown in FIG. 8, in a second mode 20, the metrology stage 510 can translate the sensor array 530 (e.g., in the X and Y axes) relative to the substrate 400 being patterned such that the sensor center 542h of the sensor 540h is aligned on the diffraction target 404e.

[0106] The rotary actuator 518 can be configured to rotate the sensor array 530 relative to the substrate 400 being patterned. In some aspects, the rotary actuator 518 can rotate the sensor array 530 relative to the substrate 400 being patterned (e.g., about the Z-axis (RZ)). In some aspects, the rotary actuator 518 can include a motor, a stepper, a servo motor, or any other suitable actuator capable of rotating about the Z-axis (RZ). In some aspects, the rotary actuator 518 can be controlled by the processor 520 to, for example, rotate one or more sensors 540a-540i of the sensor array 530 relative to a corresponding one or more diffraction targets 404a-404g on the substrate 400 being patterned. For example, as shown in FIG. 14 , in the fourth mode 40, the metrology stage 510 can rotate sensors 540n-540i for simultaneous (parallel) measurements. 25 is aligned on the diffractive target 404b, and the sensor 540n 38 The high-density sensor array 530'''' can be rotated (e.g., about the Z-axis (RZ)) by a relative rotation angle 532 (e.g., about 30°) with respect to the substrate 400 being patterned so that is aligned on the diffraction target 404e.

[0107] The processor 520 may be configured to control the metrology stage 510 and the sensor array 530. The processor 520 may be further configured to send and receive one or more control signals between the metrology stage 510 (e.g., including the optical ports 514a-514i, the linear actuator 516, and / or the rotary actuator 518) and the sensor array 530. The processor 520 may be further configured to send illumination control signals and / or illumination beams 544a-544i to the sensor array 530. The processor 520 may be further configured to send detection control signals to the sensor array 530. The processor 520 may be further configured to receive and process signal beams 546a-546i from the sensor array 530. In some aspects, the processor may be electrically and / or optically coupled to the metrology stage 510 (e.g., including the optical ports 514a-514i, the linear actuator 516, and the rotary actuator 518) and the sensor array 530. In some aspects, the processor 520 may be separate from the metrology stage 510. In some aspects, the processor 520 may be included within the metrology stage 510, as shown in FIG.

[0108] In some aspects, the processor 520 may be configured to measure a characteristic of one or more of the diffraction targets 404a-404g based on the signal beams 546a-546i collected from the sensor array 530. For example, the characteristic may be an alignment position of one or more of the diffraction targets 404a-404g. For example, the characteristic may be an overlay error of one or more of the diffraction targets 404a-404g.

[0109] The sensor array 530 may be configured to illuminate one or more diffraction targets 404a-404g on the substrate 400 being patterned and detect corresponding signal beams 546a-546i comprising diffraction order sub-beams (e.g., similar to the first, second, and third diffraction order sub-beams 292, 294, and 296 shown in FIGS. 2A and 2B) reflected from the one or more diffraction targets 404a-404g. As shown in FIG. 5, the sensor array 530 may include sensors 540a-540i having sensor centers 542a-542i. The sensors 540a-540i may apply (e.g., sequentially) one or more illumination beams 544a-544i toward corresponding diffraction targets 404a-404g on the substrate 400 being patterned and detect the resulting signal beams 546a-546i, respectively. In some aspects, sensor array 530 can receive illumination beams 544a-544i from metrology stage 510 (e.g., from an illumination source via processor 520). In some aspects, sensor array 530 can send detected signal beams 546a-546i to processor 520 (e.g., via optical coupling, optical fiber, waveguide, etc.).

[0110] In some aspects, the sensor array 530 may be an m×n array, where m = 2, 3, 4, ..., 1,000, and n = 2, 3, 4, ..., 1,000 (e.g., a 20x30 array, a 60x40 array, a 100x100 array, a 1,000x1,000 array, etc.). For example, as shown in FIG. 6, the sensor array 530 may be a 3x3 array. For example, as shown in FIG. 13, the high-density sensor array 530'''' may be a 9x9 array. In some aspects, the sensors 540a-540i of the sensor array 530 may be arranged in a symmetrical array (e.g., an m×m array). For example, as shown in FIG. 6, the sensors 540a-540i may be arranged in a 3x3 array. In some aspects, sensors 540a-540i of sensor array 530 may be arranged in an asymmetric array (e.g., an m×n array (m≠n)). In some aspects, sensor array 530 may overfill the underlying patterned substrate 400. For example, as shown in FIG. 6, sensor array 530 may have a rectangular (e.g., square) shape with a diagonal (e.g., 400 mm) that is larger than the diameter (e.g., 300 mm) of substrate 400 to be patterned.

[0111] In some aspects, the sensor array 530 may include one or more integrated optical chips. For example, the sensor array 530 may include one or more integrated optical chips 200 shown in FIGS. 2A and 2B. In some aspects, each sensor 540a-540i of the sensor array 530 may be the integrated optical chip 200 shown in FIGS. 2A and 2B, where each sensor 540a-540i is independently controllable and coupled to the processor 520. In some aspects, the sensor array 530 may include one or more integrated optical interconnects. For example, as shown in FIG. 16, the integrated optical element sensor array 530''''' may include input waveguides 552a-552i coupled to the illumination source 550, optical switches 554a-554i directed toward the diffractive targets 404a-404g, and output waveguides 556a-556i coupled to the detector 560.

[0112] In some aspects, the sensor device 500 may be configured to measure the diffraction targets 404a-404g at a rate of at least 30 diffraction targets per second (e.g., at a rate of 32 diffraction targets per second). In some aspects, the sensor device 500 may be configured to measure the diffraction targets 404a-404g at a rate of at least 50 diffraction targets per second (e.g., at a rate of 50 diffraction targets per second). In some aspects, the sensor device 500 may be configured to measure the diffraction targets 404a-404g at a rate of at least 55 diffraction targets per second (e.g., at a rate of 55 diffraction targets per second). In some aspects, the sensor device 500 may be configured to measure the diffraction targets 404a-404g at a rate of at least 60 diffraction targets per second (e.g., at a rate of 60 diffraction targets per second).

[0113] In some aspects, the sensor device 500 can be configured to measure the diffraction targets 404a-404g at a rate based on the density of the sensors 540a-540i relative to the diffraction targets 404a-404g. For example, the sensor device 500 can measure the diffraction targets at a rate of at least 30 diffraction targets per second based on a density of at least about 1:3 or 0.3 times (e.g., a 6x10 array for 200 targets). For example, the sensor device 500 can measure the diffraction targets at a rate of at least 50 diffraction targets per second based on a density of at least about 1:2 or 0.5 times (e.g., a 10x10 array for 200 targets). For example, the sensor device 500 can measure the diffraction targets at a rate of at least 55 diffraction targets per second based on a density of at least about 1:1.8 or 0.55 times (e.g., an 11x15 array for 300 targets). For example, sensor device 500 can measure diffractive targets at a rate of at least 60 diffractive targets per second based on a density of at least about 1:1.6 or 0.6 times (e.g., a 12x15 array for 300 targets). For example, sensor device 500 can measure diffractive targets at a rate of at least 100 diffractive targets per second based on a density of at least about 1:1 or 1 times (e.g., a 20x20 array for 400 targets).

[0114] In some aspects, the sensor device 500 may be configured to measure the diffraction targets 404a-404g at a rate of at least 20 ms per diffraction target. In some aspects, the sensor device 500 may be configured to measure the diffraction targets 404a-404g at a rate of at least 18 ms per diffraction target. In some aspects, the sensor device 500 may be configured to measure the diffraction targets 404a-404g at a rate of at least 15 ms per diffraction target. In some aspects, the sensor device 500 may be configured to measure the diffraction targets 404a-404g at a rate of at least 10 ms per diffraction target. In some aspects, the sensor device 500 may be configured to measure the diffraction targets 404a-404g at a rate of at least 5 ms per diffraction target. In some aspects, the sensor device 500 may be configured to measure the diffraction targets 404a-404g at a rate of at least 1 ms per diffraction target.

[0115] In some aspects, the sensor apparatus 500 may be utilized in a lithographic apparatus and configured to measure errors in the lithographic apparatus. For example, the sensor apparatus 500 may be utilized in the lithographic apparatus LA shown in FIG. 1 to measure overlay errors on a substrate W. In some aspects, the sensor apparatus 500 may be configured to reduce errors in a lithographic process (e.g., in the lithographic apparatus LA). For example, overlay errors may be reduced (e.g., for at least 300 targets) based on detection of high spatial frequency deformations of the substrate 400 being patterned.

[0116] In some aspects, the density of sensors 540a-540i is at least equal to (e.g., 1:1 or 1x) the density of diffraction targets 404a-404g. For example, as shown in FIG. 18, the number of sensors 540a-540i in integrated optic sensor array 530'''''' is equal to the number of diffraction targets 404a-404i on patterned substrate 400' (e.g., a 3x3 array for 9 targets). In some aspects, the density of sensors 540a-540i is at least 5x (e.g., 5:1 or 5x) the density of diffraction targets 404a-404g (e.g., a 25x25 array for 125 targets). In some aspects, the density of sensors 540a-540i is at least 10x (e.g., 10:1 or 10x) the density of diffraction targets 404a-404g (e.g., a 50x50 array for 250 targets).

[0117] In some aspects, each sensor 540a-540i of the sensor array 530 may include an integrated optics chip. For example, the integrated optics chip may include the integrated optics chip 200 shown in FIGS. 2A and 2B. In some aspects, each sensor 540a-540i of the sensor array 530 may include an integrated optics chip including an illumination source configured to provide an illumination beam 544a-544i, an optical element configured to direct the illumination beam 544a-544i toward the diffractive targets 404a-404g, and a detector configured to detect the signal beam 546a-546i. For example, the integrated optics chip may include the integrated optics chip 200 shown in FIGS. 2A and 2B, which has the illumination system 220, the tunable optical element 250, and the detection system 270.

[0118] In some aspects, each sensor 540a-540i of sensor array 530 may include an integrated optical interconnect. For example, as shown in FIGS. 15 and 16 , sensor device 500′ may include an integrated optics sensor array 530′″″ optically coupled to illumination source 550 and detector 560. In some aspects, each sensor 540a-540i of sensor array 530 may include an integrated optical interconnect including an input waveguide configured to receive illumination beam 544a-544i, an optical switch configured to direct illumination beam 544a-544i toward diffractive targets 404a-404g and receive signal beam 546a-546i, and an output waveguide configured to transmit signal beam 546a-546i. For example, as shown in FIGS. 15 and 16, sensor device 500' may include integrated optical element sensor array 530''''' having input waveguides 552a-552i, optical switches 554a-554i, and output waveguides 556a-556i, respectively.

[0119] In some aspects, the sensor array 530 can overfill the surface area of ​​the substrate 400 being patterned. For example, as shown in FIG. 6, the sensor array 530 overfills (extends beyond) the outside of the substrate 400 being patterned. In some aspects, the sensor array 530 can exactly fill the surface area of ​​the substrate 400 being patterned. For example, as shown in FIG. 11, a congruent sensor array 530'' is congruent to the outside of the substrate 400 being patterned. In some aspects, the sensor array 530 can underfill the surface area of ​​the substrate 400 being patterned. For example, as shown in FIG. 12, an underfilled sensor array 530''' underfills (is contained within) the outside of the substrate 400 being patterned.

[0120] In some aspects, the sensor apparatus 500 may include an optical coupler between the sensor array 530 and the metrology stage 510. The optical coupler is configured to transmit a signal beam 546a-546i from each sensor 540a-540i to an optical port 514a-514i, respectively. For example, as shown in FIGS. 17 and 18, the sensor apparatus 500'' may include an optical coupler 570 having a waveguide 572a-572i optically coupled to each sensor 540a-540i and an optical port 514a-514i (which may be fixed). In some aspects, the sensor apparatus 500 may include multiple optical couplers, each having a sensor 540a-540i positioned in a predetermined (customized) position, that may be individually swapped between the sensor array 530 and the metrology stage 510 for each patterned substrate 400.

[0121] 7 illustrates the sensor apparatus 500 in a first mode 10 according to an exemplary aspect. As shown in FIGS. 6 and 7, the sensor apparatus 500 may be configured to sequentially measure the diffraction targets 404a-404g such that the metrology stage 510 moves the sensor 540b of the sensor array 530 over the diffraction target 404c (e.g., in the X and Y axes) based on the minimum distance 406 between the sensor 540b and the diffraction target 404c. As shown in FIG. 7, in the first mode 10, the sensor center 542b of the sensor 540b is aligned over the diffraction target 404c.

[0122] FIG. 8 illustrates the sensor apparatus 500 in a second mode 20 according to an exemplary aspect. As shown in FIGS. 7 and 8, the sensor apparatus 500 may be configured to sequentially measure the diffraction targets 404a-404g such that after measuring the diffraction target 404c with the sensor 540b in the first mode 10 shown in FIG. 7, the metrology stage 510 moves the sensor 540h of the sensor array 530 (e.g., in the X and Y axes) onto the diffraction target 404e based on the minimum distance 406 between the sensor 540h and the diffraction target 404e. As shown in FIG. 8, in the second mode 20, the sensor center 542h of the sensor 540h is aligned on the diffraction target 404e.

[0123] In some aspects, the sensor apparatus 500 may be further configured to determine the minimum distance 406 based on an optimization algorithm (e.g., via the processor 520) that considers the relative distances between all of the sensors 540a-540i and all of the diffraction targets 404a-404g. For example, the optimization algorithm may utilize gradient descent, linear regression, neural networks, finite differences, or any other algorithm sufficient to determine the minimum distance 406. In some aspects, the optimization algorithm may further determine an optimized sequence of the minimum distances 406 and a corresponding sequential order of measurements of the diffraction targets 404a-404g.

[0124] 9 and 10 illustrate a sensor device 500 in a third mode 30 having an overlapping sensor array 530′ according to an example aspect. The overlapping sensor array 530′ can be configured to simultaneously measure the diffractive targets 404a-404g. The overlapping sensor array 530′ can be further configured such that each sensor 540a-540i has an overlapping field of view 548a-548i that overlaps with an adjacent sensor.

[0125] The side view of the sensor array 530 shown in Figures 5 and 6 may be similar to, for example, the side view of the overlapping sensor array 530' shown in Figures 9 and 10. Like reference numerals are used to indicate like features of the side view of the sensor array 530 shown in Figures 5 and 6 and the side view of the overlapping sensor array 530' shown in Figures 9 and 10. As shown in Figures 9 and 10, the overlapping sensor array 530' includes overlapping fields of view 548a-548i that allow for simultaneous (parallel) measurement of all of the diffraction targets 404a-404g, rather than the sensor array 530 using sequential measurement of the diffraction targets 404a-404g shown in Figures 5 and 6.

[0126] As shown in FIGS. 9 and 10, in the third mode 30, the overlapping sensor array 530′ can include overlapping fields of view 548a-548i. The field of view is the observable area (e.g., solid angle) of the optical device and is the maximum area that the optical device can measure. The overlapping fields of view 548a-548i represent the maximum area that the corresponding sensor 540a-540i can measure on the substrate 400 being patterned. Because each diffraction target 404a-404g is located within at least one overlapping field of view 548a-548i, the overlapping fields of view 548a-548i can be configured to simultaneously measure all diffraction targets 404a-404g on the substrate 400 being patterned (parallel measurement). As shown in FIGS. 9 and 10, each sensor 540a-540i of the overlapping sensor array 530′ has an overlapping field of view 548a-548i that overlaps with its neighboring sensor. For example, as shown in FIG. 10, overlapping field of view 548a of sensor 540a overlaps (extends into) overlapping fields of view 548b, 548d, 548e of sensors 540b, 540d, 540e, respectively.

[0127] 11 illustrates a sensor device 500 having a congruent sensor array 530″, according to an example aspect. The congruent sensor array 530″ can be configured to match (equal to) the shape of the underlying patterned substrate 400.

[0128] The side view of the sensor array 530 shown in FIGS. 5 and 6 and the side view of the congruent sensor array 530'' shown in FIG. 11 may be similar. Like reference numerals are used to indicate like features of the side views of the sensor array 530 shown in FIGS. 5 and 6 and the congruent sensor array 530'' shown in FIG. 11. As shown in FIG. 11, the congruent sensor array 530'' is congruent (aligned) with the underlying patterned substrate 400 and may have the same dimensions as the patterned substrate 400 without the overfilling portion, rather than the sensor array 530 overfilling the underlying patterned substrate 400 shown in FIGS. 5 and 6.

[0129] As shown in FIG. 11 , the congruent sensor array 530″ can include a diameter equal to the diameter of the substrate 400 being patterned. In some aspects, the surface area of ​​the congruent sensor array 530″ and the surface area of ​​the substrate 400 being patterned can be equal. For example, as shown in FIG. 11 , the congruent sensor array 530″ can have a circular (e.g., wafer-shaped) shape with a diameter (e.g., 300 mm) that matches the substrate 400 being patterned.

[0130] 12 illustrates a sensor device 500 having an underfilled sensor array 530''', according to an example aspect. The underfilled sensor array 530''' can be configured to have a feature that is smaller than (is internal to) the feature of the underlying patterned substrate 400. The underfilled sensor array 530''' can further be configured to provide a higher density of sensors 540a-540i relative to diffractive targets 404a-404g for a particular area (e.g., a particular field size) on the patterned substrate 400.

[0131] The side view of the sensor array 530 shown in FIGS. 5 and 6 and the side view of the underfilled sensor array 530''' shown in FIG. 12, for example, may be similar. Like reference numerals are used to indicate like features of the side views of the sensor array 530 shown in FIGS. 5 and 6 and the underfilled sensor array 530''' shown in FIG. 11. As shown in FIG. 12, the underfilled sensor array 530''' can underfill the underlying patterned substrate 400, having smaller dimensions than the patterned substrate 400, rather than the sensor array 530 overfilling the underlying patterned substrate 400 shown in FIGS. 5 and 6.

[0132] As shown in FIG. 12, the underfilled sensor array 530''' can include a diameter (or diagonal) that is smaller than the diameter of the substrate 400 being patterned. In some aspects, the surface area of ​​the underfilled sensor array 530''' can be smaller than the surface area of ​​the substrate 400 being patterned. For example, as shown in FIG. 12, the underfilled sensor array 530''' can have a rectangular (e.g., square) shape with a diagonal (e.g., 250 mm) that is smaller than the diameter (e.g., 300 mm) of the substrate 400 being patterned.

[0133] 13 and 14 illustrate a sensor device 500 having a high density sensor array 530'''' according to an example aspect. The high density sensor array 530'''' includes sensors 540n with a high density (e.g., at least 1:1 or 1x, e.g., 81:7 or 11.6x) of sensors relative to the diffractive targets 404a-404g. 11 ~540n 99 It can be configured to provide a 9x9 array.

[0134] The side view of the sensor array 530 shown in FIGS. 5 and 6 may be similar to, for example, the side view of the high density sensor array 530'''' shown in FIGS. 13 and 14. Like reference numerals are used to indicate like features of the side view of the sensor array 530 shown in FIGS. 5 and 6 and the side view of the high density sensor array 530'''' shown in FIGS. 13 and 14. As shown in FIGS. 13 and 14, the high density sensor array 530'''' has sensors 540n that can be rotated relative to the patterned substrate 400 at a high density (e.g., 81:7 or 11.6 times) relative to the diffractive targets 404a-404g, rather than the sensor array 530 (e.g., a 3x3 array) having a lower sensor:target density (e.g., 9:7 or 1.3 times) shown in FIGS. 11 ~540n 99 (9x9 array).

[0135] As shown in FIGS. 13 and 14, the high density sensor array 530'''' (a 9x9 array) has rows 540n 11 ~540n 91 and column 540n 11 ~540n 19 Sensor 540n with 11 ~540n 99 In some aspects, the high density sensor array 530'''' may be an m x n array, where m = 4, 5, 6, ..., 1,000, and n = 4, 5, 6, ..., 1,000 (e.g., a 20x30 array, a 60x40 array, a 50x50 array, a 100x100 array, a 1,000x1,000 array, etc.). For example, as shown in FIG. 13, the high density sensor array 530'''' may be a 9x9 array.

[0136] 14 illustrates the sensor apparatus in a fourth mode 40 according to an example aspect. As shown in FIGS. 13 and 14, the sensor apparatus 500 detects the position of the sensors 540n of the high density sensor array 530'''' when the metrology stage 510 detects the position of the sensors 540n of the high density sensor array 530'''' based on the relative rotation angle 532 (e.g., from the central axis 531) between the high density sensor array 530'''' and the substrate 400 being patterned. 25 , 540n38 14, in the fourth mode 40, after rotation to a relative rotation angle 532, the sensors 540n 25 is aligned on the diffractive target 404b, and the sensor 540n 38 may be aligned on diffractive target 404e and simultaneously measured by high-density sensor array 530''''. In some aspects, relative rotation angle 532 may include a range of 0° to 45°. For example, as shown in FIG. 14, relative rotation angle 532 may be approximately 30°.

[0137] In some aspects, the sensor apparatus 500 may be further configured to determine a relative rotation angle 532 over a range of 0° to 45° based on an optimization algorithm (e.g., via the processor 520) that considers the respective relative rotations between all of the sensors 540a-540i and all of the diffraction targets 404a-404g. For example, the optimization algorithm may utilize gradient descent, linear regression, neural networks, finite differences, or any other algorithm sufficient to determine the relative rotation angle 532. In some aspects, the optimization algorithm may further determine an optimized sequence of the relative rotation angles 532 and a corresponding sequential order for the simultaneous (parallel) measurements of the diffraction targets 404a-404g.

[0138] Exemplary Sensor Apparatus with Integrated Optics

[0139] 15 and 16 illustrate a sensor apparatus 500′ according to an exemplary aspect. The sensor apparatus 500′ may be configured to utilize integrated optics to form an optical routing network of sensors 540a′-540i′ for continuous, independently controllable measurement of one or more diffractive targets 404a-404g. The sensor apparatus 500′ may further be configured to utilize an integrated optics sensor array 530′″″ having a wafer-scale profile and reduced dwell time (e.g., approximately 10 μs). The sensor apparatus 500′ may further be configured to utilize an integrated optics sensor array 530′″″ formed from wafer-scale fabrication for increased density (e.g., approximately 0.5 mm x 0.5 mm sensor 540a′-540i′ unit cell dimensions) and reduced working distance (e.g., at most approximately 10 mm). Although the sensor apparatus 500' is shown in Figures 15 and 16 as a standalone apparatus and / or system, aspects of the present disclosure may be used in conjunction with other apparatus, systems, and / or methods (e.g., lithographic apparatus LA, integrated optical chip 200, substrate table 300, substrate to be patterned 400, substrate to be patterned 400', sensor apparatus 500, and / or sensor apparatus 500'').

[0140] The side view of sensor apparatus 500 shown in Figures 5 and 6 may be similar to, for example, the side view of sensor apparatus 500' shown in Figures 15 and 16. Like reference numerals are used to indicate like features of the side view of sensor apparatus 500 shown in Figures 5 and 6 and the overlapping side view of sensor apparatus 500' shown in Figures 15 and 16. As shown in Figures 15 and 16, sensor apparatus 500' includes an integrated optical element sensor array 530''''' optically coupled to an illumination source 550 and a detector 560, rather than the sensor array 530 of sensor apparatus 500 shown in Figures 5 and 6.

[0141] As shown in FIGS. 15 and 16 , the sensor device 500′ may include an integrated optics sensor array 500″′″ optically coupled to an illumination source 550 and a detector 560 of the metrology stage 510 via input waveguides 552a-552i and output waveguides 556a-556i, respectively. The integrated optics sensor array 500′′″ may be configured to illuminate one or more diffraction targets 404a-404g on the substrate 400 to be patterned and detect corresponding signal beams 546a-546i comprising diffraction order sub-beams (e.g., similar to the first, second, and third diffraction order sub-beams 292, 294, and 296 shown in FIGS. 2A and 2B ) reflected from the one or more diffraction targets 404a-404g. In some aspects, the integrated optics sensor array 500′′″ may be monolithic (e.g., a single wafer). In some aspects, integrated optics sensor array 500''''' can be fixed (e.g., thermally and / or mechanically anchored) relative to metrology stage 510 for reduced internal deformation drift (e.g., drift less than 0.1 nm). As shown in Figures 15 and 16, integrated optics sensor array 500''''' can include sensors 540a'-540i' in an optical routing network formed by input waveguides 552a-552i, optical switches 554a-554i, and output waveguides 556a-556i, respectively.

[0142] The input waveguides 552a-552i may be configured to transmit the illumination beams 544a-544i from the illumination source 550 to the optical switches 554a-554i. As shown in FIG. 16, the input waveguides 552a-552i may form an optical network optically connecting adjacent sensors 540a′-540i′. In some aspects, the input waveguides 552a-552i may comprise silicon nitride, lithium niobate, or any other suitable material capable of transmitting the illumination beams 544a-544i. In some aspects, the input waveguides 552a-552i may be formed along one or two axes. For example, as shown in FIG. 16, the input waveguides 552a-552i are formed along the Y-axis. In some aspects, the input waveguides 552a-552i may be formed along both axes (e.g., the X-axis and the Y-axis). In some aspects, input waveguides 552a-552i may comprise tapered waveguides for reduced stitching error and misalignment loss (e.g., loss less than 4 mdB). For example, each input waveguide 552a-552i may comprise a tapered waveguide having a waveguide width of at least about 5 μm at the distal (interconnect) end, while the proximal (body) portion may have a tapered waveguide width of about 1 μm.

[0143] Optical switches 554a-554i may be configured to receive illumination beams 544a-544i from input waveguides 552a-552i and direct illumination beams 544a-544i toward diffraction targets 404a-404g, receive signal beams 546a-546i from diffraction targets 404a-404g, and direct signal beams 546a-546i toward output waveguides 556a-556i. In some aspects, optical switches 554a-554i may include MEMS optical switches. For example, optical switches 554a-554i may include MEMS-actuated adiabatic couplers (e.g., 2-way optical switches). In some aspects, optical switches 554a-554i may include 3-way optical switches. For example, optical switches 554a-554i may include three 1-way optical switches (e.g., MEMS optical switches) to form a 3-way optical switch. For example, optical switches 554a-554i may include two two-way optical switches (e.g., MEMS optical switches) to form a three-way optical switch. In some aspects, optical switches 554a-554i may have an insertion loss of less than about 0.2 dB and an extinction ratio of less than about 60 dB.

[0144] Output waveguides 556a-556i may be configured to receive signal beams 546a-546i from optical switches 554a-554i and transmit signal beams 546a-546i to detector 560. As shown in FIG. 16 , output waveguides 556a-556i may form an optical network optically connecting adjacent sensors 540a′-540i′. In some aspects, output waveguides 556a-556i may comprise silicon nitride, lithium niobate, or any other suitable material capable of transmitting signal beams 546a-546i. In some aspects, output waveguides 556a-556i may be formed along one or two axes. For example, as shown in FIG. 16 , output waveguides 556a-556i are formed along the Y-axis. In some aspects, the output waveguides 556a-556i may be formed along both axes (e.g., X- and Y-axes). In some aspects, the output waveguides 556a-556i may comprise tapered waveguides for reduced stitching errors and misalignment losses (e.g., losses less than 4 mdB). For example, each output waveguide 556a-556i may comprise a tapered waveguide having a waveguide width of at least about 5 μm at the distal (interconnect) end, while the proximal (body) portion may have a tapered waveguide width of about 1 μm.

[0145] In some aspects, illumination may be directed only to specific sensors 540a'-540i'. For example, a particular illumination beam 544a-544i from illumination source 550 may be directed to a corresponding sensor 540a'-540i' so that not all sensors 540a'-540i' are illuminated simultaneously, conserving power and directing illumination only to the sensors 540a'-540i' needed for a particular measurement. In some aspects, sensors 540a'-540i' may be optically coupled to one another via one or more waveguides. 16A, each sensor 540a'-540i' may include a first waveguide 581 (e.g., along the Y-axis), a second waveguide 583 (e.g., along the X-axis), and an optical switch network 588 to guide illumination (e.g., illumination beam 544a-544i and / or signal beam 546a-546i) to and from the illumination and detector optics 580 of the respective sensor 540a'-540i' and to port the illumination between adjacent sensors 540a'-540i'. In some aspects, the illumination and detection optics 580 may be configured to guide the illumination beams 544a-544i to one or more diffractive targets 404a-404g on the substrate 400 to be patterned and to detect the corresponding signal beams 546a-546i.

[0146] In some aspects, as shown in FIG. 16A , each sensor 540a′-540i′ may include illumination and detection optics 580, a first waveguide 581 (e.g., a Y-axis input optically coupled to an adjacent sensor 540a′-540i′ along the Y-axis), a first optical switch 582a, a second optical switch 582b, a second waveguide 583 (e.g., an X-axis input optically coupled to an adjacent sensor 540a′-540i′ along the X-axis), a third optical switch 584a, a fourth optical switch 584b, a third waveguide 585 (e.g., optically coupled to illumination and detection optics 580), a fifth optical switch 586a, and a sixth optical switch 586b.

[0147] In some aspects, each sensor 540a'-540i' may include a three-way optical switch for guiding light in three directions. For example, as shown in FIG. 16A, each sensor 540a'-540i' may include an optical switch network 588 that may include, for example, two two-way optical switches (e.g., first optical switch 582a and second optical switch 582b; third optical switch 584a and fourth optical switch 584b; fifth optical switch 586a and sixth optical switch 586b) to form a three-way optical switch. In some aspects, optical switch network 588 may include one or more MEMS optical switches (e.g., MEMS-actuated adiabatic couplers). For example, as shown in FIG. 16A, first optical switch 582a, second optical switch 582b, third optical switch 584a, fourth optical switch 584b, fifth optical switch 586a, and sixth optical switch 586b may include MEMS optical switches (e.g., MEMS-actuated adiabatic couplers).

[0148] In some aspects, as shown in FIG. 16B , optical switch network 588 may include first waveguide 591 (e.g., a Y-axis input optically coupled to adjacent sensors 540a′-540i′ along the Y-axis), first optical switch 592a, second optical switch 592b, second waveguide 593 (e.g., an X-axis input optically coupled to adjacent sensors 540a′-540i′ along the X-axis), third optical switch 594a, fourth optical switch 594b, third waveguide 595 (e.g., a 90° local waveguide of the Y-axis to the negative X-axis), fifth optical switch 596a, sixth optical switch 596b, and fourth waveguide 597 (e.g., a −90° local waveguide of the Y-axis to the positive X-axis). In some aspects, as shown in FIG. 16B, optical switch network 588 may include, for example, three one-way optical switches (e.g., first optical switch 592a, second optical switch 592b, and third optical switch 594a) to form a three-way optical switch. In some aspects, optical switch network 588 may include one or more single optical switches (e.g., MEMS optical switches). For example, as shown in FIG. 16B, first optical switch 592a, second optical switch 592b, third optical switch 594a, fourth optical switch 594b, fifth optical switch 596a, and sixth optical switch 596b may include MEMS optical switches.

[0149] Exemplary Sensor Apparatus with Optical Coupler

[0150] 17 and 18 illustrate a sensor apparatus 500″ according to an exemplary aspect. The sensor apparatus 500″ may be configured to utilize an optical coupler 570 having waveguides 572a-572i as an interchangeable (swappable) optical routing network that optically couples sensors 540a-540i located at predetermined positions to optical ports 514a-514i (which are fixed) of the metrology stage 510 via waveguides 572a-572i. The sensor apparatus 500″ may further be configured to utilize an optical coupler 570 having waveguides 572a-572i that optically connect wafer-scale profiles to predetermined (customized) sensor 540a-540i positions on corresponding diffraction targets 404a-404i on the substrate 400′ to be patterned. The sensor apparatus 500'' may be further configured to utilize (e.g., interchange) multiple optical couplers 570, each having sensors 540a-540i at different predetermined (customized) positions, and to interchange a particular optical coupler 570 for a corresponding particular patterned substrate 400'. Although the sensor apparatus 500'' is shown in Figures 17 and 18 as a standalone apparatus and / or system, aspects of the present disclosure may be used in conjunction with other apparatus, systems, and / or methods (e.g., lithography apparatus LA, integrated optical chip 200, substrate table 300, substrate to be patterned 400, substrate to be patterned 400', sensor apparatus 500, and / or sensor apparatus 500').

[0151] The side view of sensor apparatus 500 shown in FIGS. 5 and 6 may be similar to, for example, the side view of sensor apparatus 500″ shown in FIGS. 17 and 18. Like reference numerals are used to indicate like features of the side view of sensor apparatus 500 shown in FIGS. 5 and 6 and the side view of sensor apparatus 500″ shown in FIGS. 17 and 18. As shown in FIGS. 17 and 18, rather than the sensor array 530 and patterned substrate 400 of sensor apparatus 500 shown in FIGS. 5 and 6, sensor apparatus 500″ includes an optical coupler 570 and an integrated optics sensor array 530″″″ having a density (number of sensors) equal to the density (number of targets) of diffractive targets 404a-404i on patterned substrate 400′.

[0152] As shown in FIGS. 17 and 18 , the sensor device 500″ may include an integrated optics sensor array 530″″″ and an optical coupler 570. The integrated optics sensor array 530″″″ may be configured to simultaneously illuminate all of the diffraction targets 404a-404i on the substrate 400′ to be patterned and detect corresponding signal beams 546a-546i, including diffraction order sub-beams (e.g., similar to the first, second, and third diffraction order sub-beams 292, 294, and 296 shown in FIGS. 2A and 2B ) reflected from the diffraction targets 404a-404i. In some aspects, as shown in FIGS. 17 and 18 , the number of sensors 540a-540i of the integrated optics sensor array 530″″″ may be equal to the number of diffraction targets 404a-404i on the substrate 400′ to be patterned (e.g., nine). In some aspects, integrated optics sensor array 500'''''' may be monolithic (e.g., a single wafer). In some aspects, integrated optics sensor array 530'''''' may include optical coupler 570. For example, integrated optics sensor array 530'''''' and waveguides 572a-572i of optical coupler 570 may be formed on the same monolithic substrate (e.g., a single wafer).

[0153] The optical coupler 570 may be configured to form an optical routing network via waveguides 572a-572i between sensors 540a-540i disposed at predetermined locations and optical ports 514a-514i (fixed) of the metrology stage 510. The optical coupler 570 may further be configured to be interchangeable (swappable) for different patterned substrates 400′. In some aspects, the optical coupler 570 may be monolithic (e.g., a single wafer). In some aspects, as shown in FIG. 17, the optical coupler 570 may be disposed between the integrated optical element sensor array 500″″″ and the metrology stage 510. As shown in FIGS. 17 and 18, the optical coupler 570 may include waveguides 572a-572i corresponding to the sensors 540a-540i. In some aspects, as shown in FIGS. 17 and 18, the number of waveguides 572a-572i of optical coupler 570 may be equal to the number of sensors 540a-540i (eg, nine).

[0154] Waveguides 572a-572i may be configured to transmit signal beams 546a-546i, respectively, from sensors 540a-540i to optical ports 514a-514i (which are fixed) of metrology stage 510. For simultaneous (parallel) measurement of all diffraction targets 404a-404i on a substrate 400' to be patterned, the waveguides 572a-572i may be further configured to optically couple each sensor 540a-540i on a corresponding diffraction target 404a-404i to each optical port 514a-514i (which are fixed) so that there is a 1:1 correspondence between the diffraction targets 404a-404i and the sensors 540a-540i, between the sensors 540a-540i and the waveguides 572a-572i, and between the waveguides 572a-572i and the optical ports 514a-514i (which are fixed). For example, as shown in Figures 17 and 18, diffraction target 404d may be measured by sensor 540d, which is optically coupled to waveguide 572d, which routes signal beam 546d of sensor 540d to optical port 514d. In some aspects, waveguides 572a-572i may comprise silicon nitride, lithium niobate, or any other suitable material capable of transmitting signal beams 546a-546i. In some aspects, waveguides 572a-572i may comprise tapered waveguides for reduced stitching errors and misalignment loss (e.g., loss less than 4 mdB). For example, each waveguide 572a-572i may comprise a tapered waveguide having a waveguide width of at least about 5 μm at the distal (interconnect) end, while a proximal (body) portion may have a tapered waveguide width of about 1 μm.

[0155] This embodiment may be further described using the following items. Item 1: A sensor array comprising a plurality of sensors, each sensor of the sensor array comprising: illuminating radiation onto a diffractive target on a substrate comprising a plurality of diffractive targets; detecting a signal beam comprising diffraction order sub-beams reflected from the diffractive target; a sensor array configured to perform a metrology stage coupled to the sensor array and configured to move the sensor array relative to the substrate; Equipped with configured to measure the plurality of diffractive targets at a rate based on a density of the plurality of sensors relative to the plurality of diffractive targets. Device. Item 2: Item 1. The apparatus of item 1, configured to measure the plurality of diffractive targets at a rate of at least 10 diffractive targets per second. Item 3: Item 1, the apparatus being configured to reduce overlay errors based on detection of high spatial frequency deformations of the substrate. Item 4: Item 1, wherein the density of the plurality of sensors is at least equal to the density of the plurality of diffractive targets. Item 5: Item 1, wherein the density of the plurality of diffractive targets is at least five times the density of the plurality of sensors. Item 6: Item 1, wherein the density of the plurality of diffractive targets is at least 10 times the density of the plurality of sensors. Item 7: 2. The apparatus of claim 1, wherein in a first mode, the metrology stage is configured to sequentially measure the plurality of diffraction targets such that a first sensor of the sensor array is moved over a first diffraction target of the plurality of diffraction targets based on a minimum distance between the first sensor and the first diffraction target. Item 8: Item 8. The apparatus of item 7, further configured to determine the minimum distance based on an optimization algorithm that takes into account relative distances between the plurality of sensors and the plurality of diffractive targets. Item 9: Item 10. The apparatus of item 1, wherein in a second mode, the metrology stage is configured to simultaneously measure the multiple diffraction targets such that at least first and second sensors of the sensor array are rotated over first and second diffraction targets of the multiple diffraction targets, respectively, based on a relative rotation angle between the sensor array and the substrate. Item 10: Item 10. The apparatus of item 9, further configured to determine the relative rotation angle based on an optimization algorithm that considers relative rotation between the plurality of sensors and the plurality of diffractive targets over a range of 0 degrees to 45 degrees. Item 11: Item 1, wherein in a third mode, the apparatus is configured to simultaneously measure the multiple diffractive targets on the substrate such that each sensor in the sensor array has a field of view that overlaps with adjacent sensors. Item 12: Each sensor in the sensor array comprises: an illumination source configured to provide an illumination beam; an optical element configured to direct the illumination beam onto the diffractive target; a detector configured to detect the signal beam; an integrated optical chip comprising: Item 1. The device according to item 1. Item 13: Each sensor in the sensor array comprises: an input waveguide configured to receive an illumination beam; an optical switch configured to direct the illumination beam toward the diffractive target and to receive the signal beam; an output waveguide configured to transmit the signal beam; an integrated optical interconnect comprising: Item 1. The device according to item 1. Item 14: a detector system including a detector; the detector system is configured to collect the signal beam; Item 14. The device according to item 13. Item 15: a processor coupled to the sensor array, the metrology stage, and the detector system; the processor is configured to measure a characteristic of the diffractive target based on the signal beam. Item 15. The device according to item 14. Item 16: Item 16. The apparatus of item 15, wherein the characteristic of the diffractive target is an alignment position or an overlay error. Item 17: Item 10. The apparatus of item 1, wherein the sensor array overfills the surface area of ​​the substrate. Item 18: Item 10. The apparatus of item 1, wherein the sensor array underfills a surface area of ​​the substrate. Item 19: A sensor array comprising a plurality of sensors arranged on a plurality of diffractive targets on a substrate, each sensor of the sensor array comprising: illuminating a diffractive target of the plurality of diffractive targets with radiation; detecting a signal beam comprising diffraction order sub-beams reflected from the diffractive target; a sensor array configured to perform a metrology stage coupled to the sensor array and configured to move the sensor array relative to the substrate; an optical coupler between the sensor array and the metrology stage, the optical coupler comprising a plurality of waveguides optically coupled to the plurality of sensors and configured to direct the signal beam from each sensor to a plurality of fixed optical ports; A detection system comprising: Item 20: 20. The detection system of item 19, comprising a plurality of optical couplers each having a plurality of sensors arranged at predetermined positions. Item 21: an illumination system configured to illuminate the patterning device; a projection system configured to project an image of the patterning device onto a substrate; a sensor device configured to measure an overlay error of the lithographic apparatus; Equipped with The sensor device includes: A sensor array comprising a plurality of sensors, each sensor of the sensor array comprising: illuminating radiation onto a diffractive target on the substrate, the diffractive target comprising a plurality of diffractive targets; detecting a signal beam comprising diffraction order sub-beams reflected from the diffractive target; a sensor array configured to perform a metrology stage coupled to the sensor array and configured to move the sensor array relative to the substrate; Equipped with the sensor device is configured to measure the plurality of diffractive targets at a rate based on a density of the plurality of sensors relative to the plurality of diffractive targets. Lithography equipment. Item 22: Item 22. A lithographic apparatus according to item 21, configured to reduce the overlay error based on detection of high spatial frequency deformations of the substrate. Item 23: 1. A method for measuring a plurality of diffractive targets on a substrate, comprising: measuring a signal beam from a plurality of diffractive targets on the substrate with a sensor device; The sensor device includes: A sensor array comprising a plurality of sensors, each sensor of the sensor array comprising: illuminating radiation onto a diffractive target on the substrate; detecting a signal beam comprising diffraction order sub-beams reflected from the diffractive target; a sensor array configured to perform a metrology stage coupled to the sensor array and configured to move the sensor array relative to the substrate; Equipped with the sensor device is configured to measure the plurality of diffractive targets at a rate based on a density of the plurality of sensors relative to the plurality of diffractive targets. method. Item 24: Item 24. The method of item 23, wherein measuring comprises sequentially measuring the plurality of diffraction targets. Item 25: 25. The method of claim 24, wherein sequentially measuring comprises translating a first sensor of the sensor array over a first diffraction target of the plurality of diffraction targets based on a minimum distance between the first sensor and the first diffraction target. Item 26: Item 24. The method of item 23, wherein measuring comprises simultaneously measuring the plurality of diffraction targets. Item 27: Item 27. The method of item 26, wherein simultaneously measuring comprises rotating at least first and second sensors of the sensor array over first and second diffraction targets of the plurality of diffraction targets, respectively, based on a relative rotation angle between the sensor array and the substrate. Item 28: 27. The method of claim 26, wherein simultaneously measuring comprises overlapping the field of view of each sensor of the sensor array with adjacent sensors. Item 29: Simultaneously measuring disposing the plurality of sensors at predetermined positions above each of the plurality of diffractive targets; detecting a signal beam from each of the plurality of sensors through an optical coupler comprising a plurality of waveguides optically coupled to the plurality of sensors and a plurality of fixed optical ports; 27. The method of claim 26, comprising: Item 30: 30. The method of claim 29, further comprising replacing the sensor array and the optical coupler with a second sensor array and a second optical coupler configured to measure a plurality of diffractive targets on a second substrate.

[0156] Although specific reference may be made in this text to the use of lithography apparatus in the manufacture of ICs, it should be understood that the lithography apparatus described herein may have other applications, such as the manufacture of integrated optical systems, guidance and detection patterns for magnetic domain memories, flat panel displays, LCDs, thin-film magnetic heads, etc. In the context of such alternative applications, those skilled in the art will recognize that any use of the terms “wafer” or “die” herein may be interpreted as synonymous with the more general terms “substrate” or “target portion,” respectively. Substrates referred to herein may be processed, before or after exposure, in, for example, a track unit (a tool that typically applies a layer of resist to a substrate and develops the exposed resist), a metrology unit, and / or an inspection unit. Where applicable, the disclosure herein may also apply to such other substrate processing tools. Furthermore, a substrate may be processed multiple times, for example to form a multi-layer IC, and the term “substrate” as used herein may refer to a substrate already including multiple processed layers.

[0157] Although specific reference may be made above to the use of aspects in the context of optical lithography, it will be understood that the aspects may be used in other applications such as imprint lithography and are not limited to optical lithography where the context allows. In imprint lithography, a topography in a patterning device defines the pattern to be created on a substrate. The topography of the patterning device may be pressed into a layer of resist supplied to the substrate, whereupon the resist is cured by applying electromagnetic radiation, heat, pressure or a combination thereof. When the patterning device is moved out of the resist after the resist is cured, it leaves a pattern in the resist.

[0158] The phrases or terms used herein are for the purpose of non-limiting description, and it is understood that the terms or phrases used herein would be interpreted by one skilled in the art given the teachings herein.

[0159] The term "substrate" as used herein describes a material onto which a layer of material is applied. In some aspects, the substrate itself may be patterned, and the material applied thereon may also be patterned or may remain unpatterned.

[0160] The following examples are non-limiting illustrations of aspects of the present disclosure. Other suitable modifications and adaptations of the variety of conditions and parameters normally encountered in the field, which are obvious to those skilled in the art, are within the spirit and scope of the disclosure.

[0161] Although specific reference may be made in this text to the use of the apparatus and / or system in the manufacture of ICs, it should be expressly understood that such apparatus and / or system have many other possible applications. For example, the apparatus and / or system may be utilized in the manufacture of integrated optical systems, guidance and detection patterns for magnetic domain memories, LCD 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 "reticle," "wafer," or "die" in this text should be construed as interchangeable with the more general terms "mask," "substrate," and "target portion," respectively.

[0162] While specific aspects have been described above, it will be understood that aspects may be practiced otherwise than as described, and the description is not intended to limit the scope of the claims.

[0163] It is understood that the Detailed Description, and not the Summary and Abstract, is intended to be used to interpret the Claims. The Summary and Abstract set forth one or more exemplary aspects contemplated by the inventors, but are not intended to be exhaustive, and are therefore not intended to limit the aspects and accompanying Claims in any manner.

[0164] Aspects have been described above using functional building blocks illustrating embodiments of specific functions and relationships thereof. The boundaries of these functional building blocks have been arbitrarily defined herein for convenience of description. Other boundaries may be defined as long as the specific functions and relationships thereof are appropriately implemented.

[0165] The foregoing description of specific aspects fully discloses the nature of the aspects so that others, by applying knowledge in the art, can readily modify and / or adapt such specific aspects for various uses without undue experimentation or departure from the concept of the aspects. Such adaptations and modifications are therefore intended to be within the meaning and range of equivalents of the disclosed aspects, based on the teaching and suggestions presented herein.

[0166] The breadth and scope of an aspect should not be limited by any of the above-described exemplary aspects, but should be defined only in accordance with the following claims and their equivalents.

Claims

1. A sensor array comprising a plurality of sensors, each sensor of the sensor array comprising: illuminating radiation onto a diffractive target on a substrate comprising a plurality of diffractive targets; detecting a signal beam comprising diffraction order sub-beams reflected from the diffractive target; a sensor array configured to perform a metrology stage coupled to the sensor array and configured to move the sensor array relative to the substrate; Equipped with configured to measure the plurality of diffractive targets at a rate based on a density of the plurality of sensors relative to the plurality of diffractive targets. Device.

2. 10. The apparatus of claim 1, configured to measure the plurality of diffractive targets at a rate of at least 10 diffractive targets per second.

3. The apparatus of claim 1 , configured to reduce overlay errors based on detection of high spatial frequency deformations of the substrate.

4. The apparatus of claim 1 , wherein a density of the plurality of sensors is at least equal to a density of the plurality of diffractive targets.

5. The apparatus of claim 1 , wherein a density of the plurality of diffractive targets is at least five times a density of the plurality of sensors.

6. The apparatus of claim 1 , wherein the density of the plurality of diffractive targets is at least 10 times the density of the plurality of sensors.

7. 2. The apparatus of claim 1, wherein in a first mode, the metrology stage is configured to sequentially measure the plurality of diffraction targets such that a first sensor of the sensor array is moved over a first diffraction target of the plurality of diffraction targets based on a minimum distance between the first sensor and the first diffraction target.

8. The apparatus of claim 7 , further configured to determine the minimum distance based on an optimization algorithm that takes into account relative distances between the plurality of sensors and the plurality of diffractive targets.

9. 2. The apparatus of claim 1, wherein in a second mode, the metrology stage is configured to simultaneously measure the plurality of diffraction targets such that at least first and second sensors of the sensor array are rotated over first and second diffraction targets of the plurality of diffraction targets, respectively, based on a relative rotation angle between the sensor array and the substrate.

10. 10. The apparatus of claim 9, further configured to determine the relative rotation angle based on an optimization algorithm that considers relative rotation between the plurality of sensors and the plurality of diffractive targets over a range of 0 degrees to 45 degrees.

11. 10. The apparatus of claim 1, configured in a third mode to simultaneously measure the plurality of diffractive targets on the substrate such that each sensor in the sensor array has a field of view that overlaps with adjacent sensors.

12. Each sensor in the sensor array comprises: an illumination source configured to provide an illumination beam; an optical element configured to direct the illumination beam onto the diffractive target; a detector configured to detect the signal beam; an integrated optical chip comprising:

10. The apparatus of claim 1.

13. Each sensor in the sensor array comprises: an input waveguide configured to receive an illumination beam; an optical switch configured to direct the illumination beam toward the diffractive target and to receive the signal beam; an output waveguide configured to transmit the signal beam; an integrated optical interconnect comprising:

10. The apparatus of claim 1.

14. a detector system including a detector; the detector system is configured to collect the signal beam; 14. The apparatus of claim 13.

15. a processor coupled to the sensor array, the metrology stage, and the detector system; the processor is configured to measure a characteristic of the diffractive target based on the signal beam.

15. The apparatus of claim 14.

Images