Single wafer particle inspection apparatus

Abstract

Systems, apparatuses, and methods for detecting particles on a surface of a substrate are provided. An example method can include receiving, by a grating structure, coherent radiation from a radiation source. The method can also include generating, by the grating structure, a focused coherent radiation beam based on the coherent radiation. The method can also include transmitting, by the grating structure, the focused coherent radiation beam toward a region of a surface of a substrate. The method can also include receiving, by the grating structure, photons scattered from the region in response to illuminating the region with the focused coherent radiation beam. The method can also include measuring, by a photodetector, the photons received by the grating structure. The method can also include generating, by the photodetector and based on the measured photons, an electronic signal for detecting a particle located in the region of the surface of the substrate.

Description

[0001] Cross-references to related applications

[0002] This application claims priority to U.S. Provisional Patent Application No. 63 / 043,543, filed June 24, 2020, and U.S. Provisional Patent Application No. 63 / 197,194, filed June 4, 2021, both of which are incorporated herein by reference in their entirety. Technical Field

[0003] This disclosure relates to particle inspection equipment that can be used, for example, in a metering system. Background Technology

[0004] A photolithography apparatus is a machine that applies a desired pattern onto a substrate, typically onto a target portion of the substrate. Photolithography apparatuses can be used, for example, in the fabrication of integrated circuits (ICs). In this context, a patterning apparatus, interchangeably referred to as a mask or photomask, can be used to generate a circuit pattern formed on a single layer of the IC being formed. This pattern can then be transferred to a target portion (e.g., comprising a portion of one or more dies) on a substrate (e.g., a silicon wafer). Pattern transfer is typically achieved via imaging onto a layer of radiation-sensitive material (e.g., resist) disposed on the substrate. Typically, a single substrate will contain a network of consecutively patterned adjacent target portions. Conventional photolithography apparatuses include so-called steppers and scanners. In a stepper, each target portion is irradiated by exposing the entire pattern onto the target portion at once. In a scanner, each target portion is irradiated by scanning the pattern with a radiation beam in a given direction (“scanning” direction) while simultaneously scanning the target portion parallel or antiparallel (e.g., opposite) to that scanning direction. A pattern can also be transferred from a patterning apparatus to a substrate by imprinting the pattern onto the substrate.

[0005] As semiconductor manufacturing processes continue to advance, the size of circuit elements has been shrinking, while the number of functional elements (such as transistors) in each device has steadily increased over the decades, following a trend commonly known as Moore's Law. To keep pace with Moore's Law, the semiconductor industry is pursuing technologies capable of producing increasingly smaller features. Photolithography devices use electromagnetic radiation to project patterns onto a substrate. The wavelength of this radiation determines the minimum size of the feature that can be patterned on the substrate. Typical wavelengths currently used are 365 nm (i-line), 248 nm, 193 nm, and 13.5 nm.

[0006] Extreme ultraviolet (EUV) radiation, such as electromagnetic radiation with wavelengths of about 50 nanometers (nm) or smaller (sometimes also referred to as soft X-rays), and including light with wavelengths of about 13.5 nm, can be used in or in conjunction with photolithography apparatuses to create extremely small features in or on substrates, such as silicon wafers. Photolithography apparatuses using EUV radiation with wavelengths in the range of 4 nm to 20 nm (e.g., 6.7 nm or 13.5 nm) can be used to form even smaller features on substrates compared to photolithography apparatuses using radiation with wavelengths of, for example, 193 nm.

[0007] Methods for generating EUV light include, but are not limited to, converting a material having elements such as xenon (Xe), lithium (Li), or tin (Sn) and having an emission line in the EUV range into a plasma state. For example, in one such method known as laser-generated plasma (LPP), plasma can be generated by irradiating a target material with an amplified beam, which may be referred to as a driving laser, in the context of an LPP source, interchangeably referred to as fuel (e.g., in the form of droplets, plates, strips, streams, or clusters of material). For this process, the plasma is typically generated in a sealed container (e.g., a vacuum chamber) and monitored using various types of metering equipment.

[0008] Within the environment of a photolithography apparatus, highly dynamic processes occur, such as mask switching, wafer switching, controlled gas flow, degassing of vacuum chamber walls, liquid distribution (e.g., photoresist coating), temperature variations, metal deposition, rapid movement of multiple actuated components, and structural wear. Over time, these dynamic processes introduce and accumulate contaminant particles within the photolithography apparatus. This contamination can include the presence of particles on the surfaces of the photolithographic patterning apparatus, which can affect the etching of the pattern itself and / or inaccuracies in subsequent patterning processes, potentially leading to damaged and / or defective circuitry.

[0009] Additionally, during inspection operations, light reflected from the illuminated pattern can produce false positives, indicating to the detector that particles exist where they are not actually present. False positives can be detrimental to photolithography. For example, false positives can slow down production by unnecessarily prompting maintenance actions (e.g., mask replacement) or even recommending the discarding of perfectly identical masks. Moreover, such signals can interfere with other light signals received from particles on the back side of the photolithography patterning apparatus. Summary of the Invention

[0010] This disclosure describes various aspects of systems, apparatus, and methods for detecting particles on a substrate surface.

[0011] In some aspects, this disclosure describes a system. The system may include a radiation source configured to generate coherent radiation. The system may also include a grating structure optically coupled to the radiation source and configured to receive coherent radiation from the radiation source, generate a focused coherent radiation beam based on the coherent radiation, propagate the focused coherent radiation beam toward a region of a substrate surface, and receive photons scattered from the region in response to irradiation of the region by the focused coherent radiation beam. The system may also include a photodetector optically coupled to the grating structure and configured to measure the photons received by the grating structure and generate an electronic signal based on the measured photons for use in detecting particles located in a region on the substrate surface. In some aspects, the grating structure may include multiple regions, and the photodetector may be configured to measure multiple sets of photons received by the multiple regions and generate an electronic signal based on the measured multiple sets of photons, wherein each set of photons has been received by a corresponding region of the grating structure.

[0012] In some aspects, the system may also include multiple grating structures and multiple photodetectors. Each grating structure may be optically coupled to a radiation source and configured to receive a corresponding portion of coherent radiation from the radiation source, generate a corresponding focused coherent radiation beam based on the corresponding portion of the coherent radiation, propagate the corresponding focused coherent radiation beam toward a corresponding region on the surface of the substrate, and receive corresponding photons scattered from the corresponding region in response to corresponding illumination of the corresponding region by the corresponding focused coherent radiation beam. Each photodetector may be optically coupled to a corresponding grating structure and configured to measure the corresponding photons received by the corresponding grating structure and generate a corresponding electronic signal based on the measured photons for use in detecting particles located in a region on the surface of the substrate.

[0013] In some aspects, this disclosure describes an integrated optical device. The integrated optical device may include a grating structure optically coupled to a radiation source and configured to receive coherent radiation from the radiation source, generate a focused coherent radiation beam based on the coherent radiation, propagate the focused coherent radiation beam toward a region of a substrate surface, and receive photons scattered from the region in response to illumination of the region by the focused coherent radiation beam. The integrated optical device may also include a photodetector optically coupled to the grating structure and configured to measure the photons received by the grating structure and generate an electronic signal based on the measured photons for use in detecting particles in a region located on the surface of the substrate. In some aspects, the grating structure may include multiple regions, and the photodetector may be configured to measure multiple sets of photons received by the multiple regions and generate an electronic signal based on the measured multiple sets of photons, wherein each set of photons has been received by a corresponding region of the grating structure.

[0014] In some aspects, the integrated optical device may also include multiple grating structures and multiple photodetectors. Each grating structure may be optically coupled to a radiation source and configured to receive a corresponding portion of coherent radiation from the radiation source, generate a corresponding focused coherent radiation beam based on the corresponding portion of the coherent radiation, propagate the corresponding focused coherent radiation beam toward a corresponding region on the surface of the substrate, and receive corresponding photons scattered from the corresponding region in response to the corresponding illumination of the corresponding region by the corresponding focused coherent radiation beam. Each photodetector may be optically coupled to the corresponding grating structure and configured to measure the corresponding photons received by the corresponding grating structure and generate a corresponding electronic signal based on the measured photons for use in detecting particles located in a region on the surface of the substrate.

[0015] In some aspects, this disclosure describes a monolithic inspection apparatus (e.g., a single-chip integrated optical particle inspection apparatus). The monolithic inspection apparatus may include a receiver configured to receive coherent radiation from a radiation source. The monolithic inspection apparatus may also include a focusing structure (e.g., a grating structure, a lens grating structure, or any other suitable structure or combination thereof) optically coupled to the receiver and configured to generate a focused coherent radiation beam based on the coherent radiation, propagate the focused coherent radiation beam toward a region on the surface of a substrate, and receive photons scattered from the region in response to irradiation of the region by the focused coherent radiation beam. The monolithic inspection apparatus may also include a photodetector optically coupled to the focusing structure and configured to measure the photons received by the focusing structure and generate an electronic signal based on the measured photons for use in detecting particles in a region located on the surface of the substrate. In some aspects, the focusing structure may include multiple regions, and the photodetector may be configured to measure multiple sets of photons received by the multiple regions and generate an electronic signal based on the measured multiple sets of photons, wherein each of the multiple sets of photons has been received by a corresponding region of the focusing structure.

[0016] In some aspects, the monolithic inspection apparatus may also include multiple focusing structures and multiple photodetectors. Each focusing structure may be optically coupled to a radiation source and configured to receive a corresponding portion of coherent radiation from the radiation source, generate a corresponding focused coherent radiation beam based on the corresponding portion of the coherent radiation, propagate the corresponding focused coherent radiation beam toward a corresponding region on the surface of the substrate, and receive corresponding photons scattered from the corresponding region in response to the corresponding illumination of the corresponding region by the corresponding focused coherent radiation beam. Each photodetector may be optically coupled to the corresponding focusing structure and configured to measure the corresponding photons received by the corresponding focusing structure and generate a corresponding electronic signal based on the measured photons for use in detecting particles located in a region on the surface of the substrate.

[0017] In some aspects, this disclosure describes a method for detecting particles on a substrate surface. The method may include receiving coherent radiation from a radiation source by a grating structure. The method may also include generating a focused coherent radiation beam by the grating structure based on the coherent radiation. The method may further include guiding the focused coherent radiation beam toward a region of the substrate surface by the grating structure. The method may further include receiving photons scattered from the region by the grating structure in response to irradiation of the region with the focused coherent radiation beam. The method may further include measuring the photons received by the grating structure by a photodetector. The method may further include generating an electronic signal for use in detecting particles located in a region on the surface of the substrate by the photodetector and based on the measured photons. In some aspects, the grating structure may include multiple regions, and the method may further include receiving multiple sets of photons scattered from the region by multiple regions of the grating structure in response to irradiation of the region with the focused coherent radiation beam, wherein each set of photons has been received by a corresponding region of the grating structure. In these aspects, the method may further include measuring the multiple sets of photons received by the multiple regions by a photodetector. In these respects, the method may also include generating an electronic signal by a photodetector based on multiple sets of photons measured.

[0018] In some aspects, the method may further include receiving a corresponding portion of coherent radiation from a radiation source by each of a plurality of grating structures, including grating structures. In these aspects, the method may further include generating a corresponding focused coherent radiation beam by each of the plurality of grating structures based on the corresponding portion of the coherent radiation. In these aspects, the method may further include transmitting the corresponding focused coherent radiation beam toward a corresponding region on the surface of the substrate by each of the plurality of grating structures. In these aspects, the method may further include receiving a corresponding photon scattered from the corresponding region by each of the plurality of grating structures in response to irradiating the corresponding region with the corresponding focused coherent radiation beam. In these aspects, the method may further include measuring the corresponding photon received by the corresponding grating structure by each of a plurality of photodetectors, including photodetectors. In these aspects, the method may further include generating a corresponding electronic signal for use in detecting particles located in a region on the surface of the substrate by each of the plurality of photodetectors and based on the measured photon.

[0019] Further features, as well as the structure and operation of each aspect, are described in detail below with reference to the accompanying drawings. It should be noted that this disclosure is not limited to the specific aspects described herein. These aspects are presented herein for illustrative purposes only. Additional aspects will be apparent to those skilled in the art based on the teachings contained herein. Attached Figure Description

[0020] The accompanying drawings, which are incorporated herein and form part of the specification, illustrate the present disclosure and, together with the description, further serve to explain the principles of various aspects of the disclosure and to enable those skilled in the art to make and use aspects of the disclosure.

[0021] Figure 1A This is a schematic diagram of an example reflective lithography apparatus according to some aspects of this disclosure.

[0022] Figure 1B This is a schematic diagram of an example transmission lithography apparatus according to some aspects of this disclosure.

[0023] Figure 2 Based on some aspects of this disclosure Figure 1A A more detailed schematic diagram of the reflective lithography apparatus shown.

[0024] Figure 3 This is a schematic diagram of an example lithography unit according to some aspects of this disclosure.

[0025] Figure 4 This is a schematic diagram of an example particle inspection system based on some aspects of this disclosure.

[0026] Figure 5 This is a schematic diagram of another example particle inspection system based on some aspects of this disclosure.

[0027] Figure 6 This is a schematic diagram of another example particle inspection system based on some aspects of this disclosure.

[0028] Figure 7 This is an example method for detecting particles on a substrate surface, according to some aspects or more parts of this disclosure.

[0029] Figure 8 It is an example computer system for implementing some aspects or more parts of this disclosure.

[0030] The features and advantages of this disclosure will become more apparent from the following detailed description set forth in conjunction with the accompanying drawings, in which the same reference numerals consistently identify corresponding elements. In the drawings, unless otherwise stated, the same reference numerals generally indicate the same, functionally similar, and / or structurally similar elements. Additionally, generally, the leftmost(s) of the reference numerals identify the drawing in which the reference numeral first appears. Unless otherwise stated, the drawings provided throughout this disclosure should not be construed as being drawn to scale. Detailed Implementation

[0031] This specification discloses one or more embodiments of the features incorporated herein. The disclosed embodiments(s) are merely illustrative of this disclosure. The scope of this disclosure is not limited to the disclosed embodiments(s). The breadth and scope of this disclosure are defined by the appended claims and their equivalents.

[0032] The described embodiments and references in the specification to "an embodiment," "an example embodiment," etc., indicate that the described embodiments may include a particular feature, structure, or characteristic, but each embodiment may not necessarily include that particular feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it should be understood that, whether explicitly described or not, the influence of such feature, structure, or characteristic on such feature, structure, or characteristic in connection with other embodiments is within the knowledge of those skilled in the art.

[0033] Spatially relative terms such as “below,” “under,” “lower,” “above,” “on top,” “upper,” etc., may be used herein to describe the relationship between one element or feature and another element(s) or feature(s) shown in the figures. In addition to the orientations depicted in the figures, spatially relative terms are intended to encompass different orientations of the device in use or operation. The device may be oriented in other ways (rotated 90 degrees or in other orientations), and the spatially relative descriptors used herein may be interpreted similarly accordingly.

[0034] As used herein, the term “about” indicates the value of a given quantity that can vary based on a particular technique. Based on a particular technique, the term “about” can mean the value of a given quantity that varies within, for example, 10% to 30% of the value (e.g., ±10%, ±20%, or ±30% of the value).

[0035] As used herein, the term "integrated optical device" refers to a monolithic device or IC, such as a single-chip particle inspection device having optical elements integrated on a single chip. In the integrated optical device described herein, light can be guided by waveguides molded from the chip. Waveguides can include Si, SiN (e.g., Si3N4), InP, AlN, TiO2, LiNbO3, any other suitable material, or any combination thereof, depending on the operating wavelength range of the integrated optical device. In some embodiments, SiN can support an operating wavelength range from about 0.3 micrometers (μm or micrometers) to about 5.5 μm, AlN can support an operating wavelength range from about 0.2 μm to about 13.6 μm, and Si can support an operating wavelength range from about 1.1 μm to about 6.5 μm. While materials such as those described above can support a wide range of wavelengths, some waveguide geometries disclosed herein (e.g., width and height) can reduce the operating wavelength range of these waveguides to even smaller wavelength ranges (e.g., a few nanometers). In some aspects, the integrated optical device described herein can increase stability due to its small and monolithic design. Additionally, the optical modules in the integrated optical devices described herein can be aligned by design (e.g., using photolithography) to reduce or substantially eliminate device-to-device differences. In some aspects, the term "monolithic device" can refer to a single-chip device. For example, the term "monolithic inspection device" can refer to an optical particle inspection device integrated on a single chip.

[0036] Overview

[0037] Some aspects of this disclosure can provide an inspection tool comprising multiple grating structures (e.g., lens grating structures) wherein optical elements are disposed on a single chip. In some aspects, incident light provided by a laser (e.g., coherent radiation at 400 nm) can be coupled into the chip via fiber-to-grating coupling. The incident light can reach the grating structure via a waveguide. Each grating structure can consist of gratings with variable line spacing to focus the light (e.g., “lensing”). Subsequently, light scattered by the sample under inspection can be collected through the same grating structure. Each grating structure can be divided into four regions to obtain a differential signal from the scattered light. Multiple parallel grating structures provided in an array or checkerboard pattern can allow for the inspection of larger areas in a single scan pass.

[0038] In some aspects, this disclosure provides for generating a pencil beam using a one-dimensional focusing element (e.g., a lens grating structure), enabling the inspection of a large area in a single scan movement. In such embodiments, the lens grating structure can be adjusted to act as a phased array of optics, which allows the beam to move laterally as it is scanned, and thus allows even larger surfaces to be inspected in a single scan. If the throughput improvement provided by a single pencil beam shape is insufficient, an array of lens grating structures can be provided to increase throughput.

[0039] Many exemplary aspects of the systems, apparatuses, methods, and computer program products disclosed herein exist. For example, aspects of the invention provide integrated optical devices that utilize a single operating wavelength (e.g., 400 nm, 1.1 μm) to allow the use of materials with suitable operating wavelengths (e.g., silicon nitride (Si3N4), Si). In another example, aspects of this disclosure provide the utilization of integrated optical devices and improved metrology techniques in inspection tools. Compared to bulk optical devices, integrated optical devices present a simple and cost-effective way to achieve parallelization. For example, using approximately 10 parallel units will achieve reasonable inspection times for patterned surfaces (e.g., 30 minutes per wafer, 100 minutes per mask). For bare surfaces, inspection tools with approximately 100 parallel units (e.g., lens grating structures and associated waveguides and balanced photodetectors) can be utilized. As a result of the techniques described in this disclosure, sufficient throughput can be obtained for optical inspection of areas with dimensions associated with IC production (e.g., mask areas, wafer areas), down to small feature sizes (e.g., small particles). Additionally, the techniques described in this disclosure can be used in combination with an electron beam (e-beam) system for mixed inspections (e.g., initially performing an optical inspection and then using an e-beam inspection only on potentially contaminated or otherwise anomalous areas).

[0040] However, before describing these aspects in more detail, it is enlightening to show an example environment in which aspects of this disclosure can be implemented.

[0041] Example lithography system

[0042] Figure 1A and Figure 1B These are schematic diagrams of photolithography apparatus 100 and photolithography apparatus 100', respectively, in which various aspects of this disclosure can be implemented. For example... Figure 1A and Figure 1BAs shown, the lithography apparatus 100 and 100' are illustrated from a viewpoint (e.g., a side view) perpendicular to the XZ plane (e.g., the X-axis points to the right, the Z-axis points upward, and the Y-axis points away from the viewer's page), while the patterning apparatus MA and the substrate W are presented from an additional viewpoint (e.g., a top view) perpendicular to the XY plane (e.g., the X-axis points to the right, the Y-axis points upward, and the Z-axis points to the viewer outside the page).

[0043] In some aspects, lithography apparatus 100 and / or lithography apparatus 100' may include one or more of the following structures: an irradiation system IL (e.g., an irradiator) configured to modulate a radiation beam B (e.g., a deep ultraviolet (DUV) radiation beam or an extreme ultraviolet (EUV) radiation beam); a support structure MT (e.g., a mask stage) configured to support a patterning device MA (e.g., a mask, a photomask, or a dynamic patterning device) and connected to a first positioner PM configured to precisely position the patterning device MA; and a substrate holder, such as a substrate stage WT (e.g., a wafer stage) configured to hold a substrate W (e.g., a wafer coated with resist) and connected to a second positioner PW configured to precisely position the substrate W. The lithography apparatuses 100 and 100' also include a projection system PS (e.g., a refractive projection lens system) configured to project a pattern, imparted by a radiation beam B by a patterning device MA, onto a target portion C (e.g., a portion comprising one or more dies) of the substrate W. In the lithography apparatus 100, the patterning device MA and the projection system PS are reflective. In the lithography apparatus 100', the patterning device MA and the projection system PS are transmissive.

[0044] In some respects, during operation, the irradiation system IL can receive a radiation beam from the radiation source SO (e.g., via...). Figure 1B The beam transmission system BD is shown in the diagram. The illumination system IL can include various types of optical structures, such as refractive, reflective, antirefractive, magnetic, electromagnetic, electrostatic, and other types of optical components, or any combination thereof, for guiding, shaping, or controlling radiation. In some aspects, the illumination system IL can be configured to adjust the radiation beam B to have a desired spatial and angular intensity distribution in a cross-section at the plane of the patterning device MA.

[0045] In some aspects, the support structure MT can hold the patterning device MA in a manner that depends on the orientation of the patterning device MA relative to the reference frame, the design of at least one of the lithography devices 100 and 100', and other conditions (such as whether the patterning device MA is held in a vacuum environment). The support structure MT can hold the patterning device MA using mechanical, vacuum, electrostatic, or other clamping techniques. The support structure MT can be, for example, a frame or a stage, and can be fixed or movable as needed. By using sensors, the support structure MT can ensure that the patterning device MA is in a desired position, for example, relative to the projection system PS.

[0046] The term "patterning device" MA should be interpreted broadly to refer to any device capable of imparting a pattern to a radiation beam B across its cross-section in order to generate a pattern in a target portion C of a substrate W. The pattern imparted to the radiation beam B can correspond to a specific functional layer in the device generated in the target portion C to form an integrated circuit.

[0047] In some respects, the patterning device MA can be transmissive (e.g., in...) Figure 1B In the photolithography apparatus 100') or reflective (such as in Figure 1A (In the lithography apparatus 100). The patterning apparatus MA can include various structures, such as a mask, a mask, a programmable mirror array, a programmable LCD panel, other suitable structures, or combinations thereof. The mask can include mask types such as binary, alternating phase-shift, or attenuation phase-shift, as well as various hybrid mask types. In one example, the programmable mirror array can include a matrix arrangement of small mirrors, each of which can be individually tilted to reflect the incident radiation beam in different directions. The tilted mirrors can impart a pattern to the radiation beam B reflected by the matrix of small mirrors.

[0048] The term "projection system" PS should be interpreted broadly and can encompass any type of projection system, including refractive, reflective, antirefractive, magnetic, distorting, electromagnetic, and electrostatic optical systems, or any combination thereof, suitable for exposure radiation in use, and / or suitable for other factors such as the use of an immersion liquid (e.g., on a substrate W) or a vacuum. A vacuum environment can be used for EUV or electron beam radiation because other gases can absorb excessive radiation or electrons. Therefore, a vacuum environment can be provided throughout the beam path by means of vacuum walls and vacuum pumps. Furthermore, in some respects, any use of the term "projection lens" herein can be interpreted as synonymous with the more general term "projection system" PS.

[0049] In some aspects, lithography apparatus 100 and / or lithography apparatus 100' may be of the type having two (e.g., "dual-stage") or more substrate stages WT and / or more than two mask stages. In such a "multi-stage" machine, additional substrate stages WT can be used in parallel, or preparation steps can be performed on one or more stages while one or more other substrate stages WT are being used for exposure. In one example, preparation steps for subsequent exposure of substrate W can be performed on substrate W located on one substrate stage of substrate stage WT, while another substrate W located on another substrate stage of substrate stage WT is being used to expose a pattern on another substrate W. In some aspects, the additional stage may not be a substrate stage WT.

[0050] In some aspects, in addition to the substrate stage WT, the lithography apparatus 100 and / or lithography apparatus 100' may include a measurement stage. The measurement stage may be arranged to hold sensors. The sensors may be arranged to measure characteristics of the projection system PS, characteristics of the radiation beam B, or both. In some aspects, the measurement stage may hold multiple sensors. In some aspects, the measurement stage may be movable below the projection system PS when the substrate stage WT is moved away from the projection system PS.

[0051] In some aspects, the lithography apparatus 100 and / or lithography apparatus 100' can also be of the type in which at least a portion of the substrate can be covered with a liquid (e.g., water) having a relatively high refractive index to fill the space between the projection system PS and the substrate W. Immersion liquids can also be applied to other spaces within the lithography apparatus (e.g., the space between the patterning apparatus MA and the projection system PS). Immersion techniques provide a method for increasing the numerical aperture of a projection system. As used herein, the term "immersion" does not mean that structures such as the substrate must be immersed in a liquid, but simply that the liquid is located between the projection system and the substrate during exposure. Various immersion techniques are described in U.S. Patent No. 6,952,253, entitled "Lithographic apparatus and device manufacturing method," published October 4, 2005, which is incorporated herein by reference in its entirety.

[0052] refer to Figure 1A and Figure 1B The irradiation system IL receives the radiation beam B from the radiation source SO. For example, when the radiation source SO is an excimer laser, the radiation source SO and the lithography apparatus 100 or 100' can be separate physical entities. In this case, the radiation source SO is not considered to be part of the lithography apparatus 100 or 100', and the radiation beam B is transmitted via a beam transport system BD (e.g., ...). Figure 1B(As shown) The beam is transmitted from the radiation source SO to the irradiation system IL, which includes, for example, suitable directional mirrors and / or beam expanders. In other cases, for example, when the radiation source SO is a mercury lamp, the radiation source SO may be an integral part of the lithography apparatus 100 or 100'. If desired, the radiation source SO and the irradiator IL together with the beam transmission system BD may be referred to as the radiation system.

[0053] In some aspects, the illumination system IL may include an adjuster AD for adjusting the angular intensity distribution of the radiation beam. Typically, at least the outer and / or inner radial ranges of the intensity distribution in the pupil plane of the illuminator (typically referred to as "σ-outer" and "σ-inner," respectively) can be adjusted. Furthermore, the illumination system IL may include various other components, such as an integrator IN and a radiation collector CO (e.g., a converging or collector optics). In some aspects, the illumination system IL can be used to adjust the radiation beam B to achieve a desired uniformity and intensity distribution in its cross-section.

[0054] refer to Figure 1A In operation, the radiation beam B can be incident on a patterning device MA (e.g., a mask, a mask plate, a programmable mirror array, a programmable LCD panel, any other suitable structure, or a combination thereof), which can be held on a support structure MT (e.g., a mask stage) and can be patterned by a pattern (e.g., a design layout) present on the patterning device MA. In the lithography apparatus 100, the radiation beam B can be reflected from the patterning device MA. After passing through the patterning device MA (e.g., after being reflected from the patterning device MA), the radiation beam B can pass through a projection system PS, which can focus the radiation beam B onto a target portion C of the substrate W or onto a sensor arranged on the stage.

[0055] In some respects, the substrate stage WT can be precisely moved, for example, to position different target portions C in the path of the radiation beam B, by means of a second positioning device PW and a position sensor IFD2 (e.g., an interferometric device, a linear encoder, or a capacitive sensor). Similarly, a first positioner PM and another position sensor IFD1 (e.g., an interferometric device, a linear encoder, or a capacitive sensor) can be used to precisely position the patterning device MA relative to the path of the radiation beam B.

[0056] In some respects, mask alignment marks M1 and M2 and substrate alignment marks P1 and P2 can be used to align the patterning device MA and the substrate W. Although Figure 1A and Figure 1BThe illustration shows substrate alignment marks P1 and P2 occupying a dedicated target area, but substrate alignment marks P1 and P2 can also be located in the space between target areas. When substrate alignment marks P1 and P2 are located between target areas C, they are referred to as scribing alignment marks. Substrate alignment marks P1 and P2 can also be arranged in the target area C region as in-die marks. These in-die marks can also be used as metrology marks, for example, for overlap measurements.

[0057] In some respects, for illustrative and not limiting purposes, one or more figures in this document may utilize a Cartesian coordinate system. A Cartesian coordinate system comprises three axes: the X-axis, the Y-axis, and the Z-axis. Each of the three axes is orthogonal to the other two axes (e.g., the X-axis is orthogonal to the Y and Z axes, the Y-axis is orthogonal to the X and Z axes, and the Z-axis is orthogonal to the X and Y axes). Rotation about the X-axis is called an Rx-rotation. Rotation about the Y-axis is called an Ry-rotation. Rotation about the Z-axis is called an Rz-rotation. In some respects, the X and Y axes define a horizontal plane, while the Z-axis is in the vertical direction. In some respects, the orientation of the Cartesian coordinate system may be different, for example, such that the Z-axis has a component along the horizontal plane. In some respects, another coordinate system (such as a cylindrical coordinate system) may be used.

[0058] refer to Figure 1B A radiation beam B is incident on a patterning device MA held on a support structure MT and patterned by the patterning device MA. After passing through the patterning device MA, the radiation beam B passes through a projection system PS, which focuses the beam onto the target portion C of the substrate W. In some aspects, the projection system PS may have a pupil conjugate with the illumination system pupil. In some aspects, the radiating portion can be emitted from the intensity distribution at the illumination system pupil and pass through the mask pattern unaffected by diffraction at the mask pattern MP, and an image of the intensity distribution is generated at the illumination system pupil.

[0059] The projection system PS projects an image MP' of a mask pattern MP onto a resist layer coated on a substrate W, wherein the image MP' is formed by a diffracted beam generated from radiation from the mask pattern MP by a distribution of intensity. For example, the mask pattern MP may comprise an array of lines and spacings. Diffraction of radiation at the array, distinct from zero-order diffraction, generates a diffracted beam with a directional change in a direction perpendicular to the lines. Reflected light (e.g., the zero-order diffracted beam) passes through the pattern without any change in its propagation direction. The zero-order diffracted beam passes upstream of the pupil conjugate of the projection system PS through the upper lens or upper lens group of the projection system PS to reach the pupil conjugate. A portion of the intensity distribution in the pupil conjugate plane and associated with the zero-order diffracted beam is an image of the intensity distribution in the pupil of the illumination system IL. In some aspects, the aperture device may be positioned or substantially positioned at the plane comprising the pupil conjugate of the projection system PS.

[0060] The projection system PS is arranged to capture not only the zeroth-order diffraction beam, but also first-order or higher-order diffraction beams (not shown) by means of a lens or lens group. In some aspects, dipole illumination for imaging a line pattern extending in a direction perpendicular to the line can be used to utilize the resolution enhancement effect of dipole illumination. For example, a first-order diffraction beam interferes with the corresponding zeroth-order diffraction beam at the level of the substrate W to produce an image of the mask pattern MP at the highest possible resolution and process window (e.g., the available depth of focus combined with permissible exposure dose deviation). In some aspects, astigmatism can be reduced by providing a radiating pole (not shown) in the opposite confinement of the pupil of the illumination system. Further, in some aspects, astigmatism can be reduced by blocking the zeroth-order beam in the pupil conjugate of the projection system PS associated with the radiating pole in the opposite confinement. This is described in more detail in U.S. Patent No. 7,511,799, entitled “Lithographic projection apparatus and a device manufacturing method,” published March 31, 2009, which is incorporated herein by reference in its entirety.

[0061] In some respects, the substrate stage WT is precisely moved by means of a second positioner PW and a position measurement system PMS (e.g., a position sensor including an interferometric device, a linear encoder, or a capacitive sensor), for example, to position different target portions C in the path of the radiation beam B in a focused and aligned position. Similarly, the first positioner PM and another position sensor (e.g., an interferometric device, a linear encoder, or a capacitive sensor) ( Figure 1B (Not shown) can be used to precisely position the patterning device MA relative to the path of the radiation beam B (e.g., after mechanical retrieval from a mask library or during scanning). The patterning device MA and the substrate W can be aligned using mask alignment marks M1 and M2 and substrate alignment marks P1 and P2.

[0062] Typically, the movement of the support structure MT can be achieved using long-stroke positioners (coarse positioning) and short-stroke positioners (fine positioning), which form part of the first positioner PM. Similarly, the movement of the substrate stage WT can be achieved using long-stroke and short-stroke positioners, which form part of the second positioner PW. In the case of a stepper (opposite to a scanner), the support structure MT may be connected only to the short-stroke actuator or may be fixed. The patterning device MA and the substrate W can be aligned using mask alignment marks M1 and M2 and substrate alignment marks P1 and P2. Although the substrate alignment marks (as shown) occupy dedicated target portions, they can be located in the space between the target portions (e.g., scribe alignment marks). Similarly, when more than one die is placed on the patterning device MA, the mask alignment marks M1 and M2 can be located between the dies.

[0063] The support structure MT and the patterning device MA can be located within a vacuum chamber V, where a robot inside the vacuum chamber can be used to move the patterning device (such as a mask) into and out of the vacuum chamber. Alternatively, when the support structure MT and the patterning device MA are outside the vacuum chamber, a robot outside the vacuum chamber can be used for various transport operations, similar to the robot inside the vacuum chamber. In some cases, both the robot inside and outside the vacuum chamber need to be calibrated for smoothly transferring any payload (e.g., a mask) to a fixed motion support at a transfer station.

[0064] In some respects, the photolithography devices 100 and 100' can be used in at least one of the following modes:

[0065] 1. In step mode, the support structure MT and substrate stage WT remain substantially stationary while the entire pattern applied to the radiation beam B is simultaneously projected onto the target portion C in one pass (e.g., a single static exposure). The substrate stage WT is then moved in the X and / or Y directions, allowing different target portions C to be exposed.

[0066] 2. In scanning mode, the support structure MT and the substrate stage WT are scanned simultaneously (e.g., single dynamic exposure) while the pattern to be applied to the radiation beam B is projected onto the target portion C. The velocity and direction of the substrate stage WT relative to the support structure MT (e.g., mask stage) can be determined by the (reduced) magnification and image inversion characteristics of the projection system PS.

[0067] 3. In another mode, the support structure MT of the programmable patterning device MA is kept substantially stationary, and the substrate stage WT is moved or scanned while the pattern to be applied to the radiation beam B is projected onto the target portion C. A pulsed radiation source SO can be used, and the programmable patterning device is updated as needed after each movement of the substrate stage WT or between consecutive radiation pulses during scanning. This operating mode can be readily applied to maskless lithography utilizing the programmable patterning device MA (such as a programmable mirror array).

[0068] In some respects, the lithography apparatuses 100 and 100' can adopt a combination and / or a variation or a completely different usage mode of the above-described usage modes.

[0069] In some aspects, such as Figure 1A As shown, the lithography apparatus 100 may include an EUV source configured to generate an EUV radiation beam B for EUV lithography. Typically, the EUV source may be configured in a radiation source SO, and the corresponding irradiation system IL may be configured to modulate the EUV radiation beam B of the EUV source.

[0070] Figure 2 The lithography apparatus 100 is shown in more detail, including a radiation source SO (e.g., a source collector device), an illumination system IL, and a projection system PS. (See attached image.) Figure 2 As shown, the lithography apparatus 100 is illustrated from a viewpoint (e.g., a side view) perpendicular to the XZ plane (e.g., the X-axis points to the right and the Z-axis points upward).

[0071] A radiation source SO is constructed and arranged such that a vacuum environment can be maintained within a closed structure 220. The radiation source SO includes a source chamber 211 and a collector chamber 212, and is configured to generate and transmit EUV radiation. EUV radiation can be generated from a gas or vapor, such as xenon (Xe), lithium (Li), or tin (Sn), wherein an EUV radiation-emitting plasma 210 is generated to emit radiation in the EUV range of the electromagnetic spectrum. The at least partially ionized EUV radiation-emitting plasma 210 can be generated, for example, by a discharge or a laser beam. For example, a partial pressure of approximately 10.0 Pascals (Pa) of Xe gas, Li vapor, Sn vapor, or any other suitable gas or vapor can be used to efficiently generate radiation. In some aspects, a plasma that excites tin is provided to generate EUV radiation.

[0072] Radiation emitted by EUV radiation-emitting plasma 210 is transmitted from source chamber 211 to collector chamber 212 via an optional gas barrier or contaminant trap 230 (e.g., in some cases also referred to as a contaminant barrier or foil trap), which is located in or behind an opening in source chamber 211. Contaminant trap 230 may include a channel structure. Contaminant trap 230 may also include a combination of a gas barrier or gas barrier layer and a channel structure. The contaminant trap 230 further indicated herein includes at least a channel structure.

[0073] Collector chamber 212 may include a radiation collector CO (e.g., a converging element or collector optics), which may be a so-called grazing incidence collector. The radiation collector CO has an upstream radiation collector side 251 and a downstream radiation collector side 252. Radiation passing through the radiation collector CO may be reflected from a grating spectral filter 240 to be focused on a virtual source point IF. The virtual source point IF is often referred to as the intermediate focus, and the source collector arrangement is such that the virtual source point IF is located at or near an opening 219 in the enclosed structure 220. The virtual source point IF is an image of the EUV radiation-emitting plasma 210. The grating spectral filter 240 may be used to suppress infrared (IR) radiation.

[0074] Subsequently, radiation passes through an illumination system IL, which may include a multifaceted field mirror device 222 and a multifaceted pupil mirror device 224. The multifaceted field mirror device 222 and the multifaceted pupil mirror device 224 are arranged to provide a desired angular distribution of the radiation beam 221 at the patterning device MA and to provide a desired uniformity of radiation intensity at the patterning device MA. When the radiation beam 221 is reflected at the patterning device MA, which is held by a support structure MT, a patterned beam 226 is formed, and the patterned beam 226 is imaged by a projection system PS via reflective elements 228 and 229 onto a substrate W held by a wafer stage or substrate stage WT.

[0075] The number of components present in the illumination system IL and projection system PS can typically be greater than those shown. Optionally, the grating spectral filter 240 may be present depending on the type of photolithography apparatus. Furthermore, the number of reflectors present may be greater than... Figure 2 The number of reflectors shown is greater. For example, compared to Figure 2 The reflective element shown can have 1 to 6 additional reflective elements in the projection system PS.

[0076] like Figure 2As shown, only as an example of a collector (or collector mirror), the radiation collector CO is depicted as a nested collector with grazing incidence reflectors 253, 254, and 255. The grazing incidence reflectors 253, 254, and 255 are configured to be symmetrical about the optical axis O, and this type of radiation collector CO is preferably used in conjunction with a discharge-generated plasma (DPP) source.

[0077] Example lithography unit

[0078] Figure 3 The image shows a lithography unit 300, sometimes also referred to as a lithography unit or cluster. For example... Figure 3 As shown, the lithography unit 300 is illustrated from a viewpoint (e.g., a top view) perpendicular to the XY plane (e.g., the X-axis points to the right and the Y-axis points upward).

[0079] The lithography apparatus 100 or 100' may form part of the lithography unit 300. The lithography unit 300 may also include one or more devices for performing pre-exposure and post-exposure processes on a substrate. For example, these devices may include a spin coater SC for depositing a resist layer, a developer DE for developing the resist during exposure, a cooling plate CH, and a baking plate BK. A substrate processor RO (e.g., a robot) picks up substrates from input / output ports I / O1 and I / O2, moves the substrates between different processing devices, and delivers them to the feed stage LB of the lithography apparatus 100 or 100'. These devices, generally referred to collectively as tracks, are under the control of a track control unit TCU, which is itself controlled by a supervisory control system SCS, which also controls the lithography apparatus via a lithography control unit LACU. Therefore, different devices can be operated to maximize throughput and processing efficiency.

[0080] Example particle inspection system

[0081] Figure 4 The illustration shows a cross-sectional schematic of a particle inspection system 400, which can be implemented as part of a photolithography apparatus 100 or 100' according to one embodiment. In one example of this embodiment, the particle inspection system 400 can be configured to align a substrate (e.g., substrate W) relative to a patterning device (e.g., patterning device MA). The particle inspection system 400 can also be configured to detect the position of alignment marks on the substrate and use the detected position of the alignment marks relative to the patterning device or other components of the photolithography apparatus 100 or 100' to align the substrate. This alignment of the substrate can ensure accurate exposure of one or more patterns on the substrate.

[0082] According to one embodiment, and in one example of that embodiment, a particle inspection system 400 may include an illumination system 412, a reflector 414 (or, additionally or alternatively, a grating structure such as a lens grating), an interferometer 426, a detector 428 (e.g., a balanced photodetector), and a controller 430. The illumination system 412 may be configured to provide a radiation beam 413. The radiation beam 413 may include, for example, a narrow electromagnetic band having one or more passbands. In another example, the one or more passbands may be discrete narrow passbands within a wavelength spectrum between about 350 nm and about 900 nm. The illumination system 412 may also be configured to provide one or more passbands having a substantially constant center wavelength (CWL) value over a long time period (e.g., during the lifetime of the illumination system 412). This configuration of the illumination system 412 can help prevent the actual CWL value in the current particle inspection system from deviating from the desired CWL value, as described above. Therefore, the use of a constant CWL value can increase the long-term stability and accuracy of a particle inspection system (e.g., particle inspection system 400) compared to current particle inspection systems.

[0083] According to one embodiment, reflector 414 may be configured to receive radiation beam 413 and guide radiation beam 413 as radiation beam 415 toward substrate 420. Reflector 414 may be a mirror or a dichroic mirror. In one example, stage 422 may be movable along direction 424. Radiation beam 415 may be configured to illuminate a plurality of alignment marks 418 or targets located on substrate 420. In another example, radiation beam 415 is configured to be reflected from the surface of substrate 420. In one example of this embodiment, the plurality of alignment marks 418 may be coated with a radiation-sensitive film. In another example, the plurality of alignment marks 418 may have 180-degree symmetry. That is, when one of the alignment marks 418 is rotated 180 degrees about an axis of symmetry perpendicular to a plane perpendicular to another alignment mark 418, the rotated alignment mark may be substantially the same as the unrotated alignment mark.

[0084] like Figure 4As shown, interferometer 426 can be configured to receive radiation beam 417. Radiation beam 419 can be diffracted from the plurality of alignment marks 418 or reflected from the surface of substrate 420 and received as radiation beam 417 at interferometer 426. Interferometer 426 may include any suitable optical and / or electro-optical element group, for example, a combination of prisms configured to form two images of the plurality of alignment marks 418 based on the received radiation beam 417. It should be understood that it is not necessary to form a high-quality image, but rather to resolve the features of the plurality of alignment marks 418. Interferometer 426 can also be configured to rotate one of the two images by 180 degrees relative to the other image and interferometrically recombine the two images.

[0085] In one embodiment, detector 428 may be configured to receive the recombined image and detect interference as a result of the recombined image when the alignment axis 421 of the particle inspection system 400 passes through the center of symmetry (not shown) of a plurality of alignment marks 418. According to one example embodiment, this interference may be due to the plurality of alignment marks 418 being 180 degrees symmetrical, and the recombined image interfering constructively or destructively. Based on the detected interference, detector 428 may also be configured to determine the position of the center of symmetry of the plurality of alignment marks 418, and thus detect the position of substrate 420. According to one example, alignment axis 421 may be aligned with a beam perpendicular to substrate 420 and passing through the center of image rotation interferometer 426. In another example, detector 428 is configured to receive the recombined image and detect interference of light reflected from the surface of substrate 420.

[0086] In another embodiment, controller 430 may be configured to receive a measurement data signal 429 including measurement data. The measurement data may include, but is not limited to, electronic information indicating the determined center of symmetry. Controller 430 may also be configured to determine the position of stage 422 and associate the position of stage 422 with the position of the center of symmetry of the plurality of alignment marks 418. Thus, the positions of the plurality of alignment marks 418, and therefore the position of substrate 420, can be accurately determined with reference to stage 422. Alternatively, controller 430 may be configured to determine the position of particle inspection system 400 or any other reference element, such that the center of symmetry of the plurality of alignment marks 418 can be determined with reference to particle inspection system 400 or any other reference element.

[0087] In one embodiment, the controller 430 is configured to apply corrections to measurements received from the detector 428 to address asymmetries that may exist among the multiple alignment marks 418. Asymmetries may arise due to defects in the structure of the marks themselves (e.g., sidewall angles, critical dimension spacing, etc.) or due to nonlinear optical effects based on the wavelength of light directed toward the multiple alignment marks 418.

[0088] It should be noted that although reflector 414 is shown guiding radiation beam 413 as radiation beam 415 toward the plurality of alignment marks 418, this disclosure is not limited thereto. It will be apparent to those skilled in the art that other optical devices can be used to obtain similar results in illuminating the plurality of alignment marks 418 on the substrate 420 and in detecting images of the plurality of alignment marks 418. Reflector 414 may guide illumination in a direction perpendicular to the surface of substrate 420 or at an angle.

[0089] Figure 5 This is a schematic diagram showing a plan view (e.g., a bottom view) of a particle inspection system 500 according to some aspects of this disclosure. In some aspects, the particle inspection system 500 or any part thereof can be implemented using the following: [Refer to...] Figure 4 The described reference particle inspection system 400 refers to any of the structures, components, features, or technologies described; reference Figure 6 The particle inspection system 600 described; Reference Figure 8 The example computing system 800 described; any of the systems, structures, components, features, or techniques described in U.S. Provisional Patent Application No. 63 / 043,543, filed June 24, 2020, entitled “Self-Referencing Integrated Alignment Sensor” (which is incorporated herein by reference in its entirety); any other suitable structures, components, features, or techniques; any part thereof; or any combination thereof.

[0090] like Figure 5 As shown, the particle inspection system 500 may include a radiation source 502 (e.g., a laser source), an optical fiber 504, an optical fiber-to-grating coupling 506, waveguides 508A-508N, lens-grating structures 510A-510N, balanced photodetectors 512A-512N, and a controller (not depicted). In some aspects, the particle inspection system 500 may be an integrated optical parallel inspection system. In some aspects, Figure 5 Some or all of the components shown can be incorporated into a single-chip particle inspection device based on Si3N4. In an illustrative and non-limiting example, the fiber-to-grating coupling 506, waveguides 508A-508N, lens grating structures 510A-510N, and balanced photodetectors 512A-512N can be disposed on a single chip.

[0091] The radiation source 502 can be configured to generate coherent radiation (e.g., with a wavelength of about 400 nm) and transmit the coherent radiation through optical fiber 504 to fiber-to-grating coupling 506, and then through one of the waveguides 508A-508N to one of the lens grating structures 510A-510N (e.g., through waveguide 508A to lens grating structure 510A, through waveguide 508B to lens grating structure 510B, and through waveguide 508N to lens grating structure 510N).

[0092] Each lens grating structure in the lens grating structures 510A-510N can be optically coupled to the radiation source 502 via one of the waveguides 508A-508N, the fiber-to-grating coupling 506, and the fiber 504 (and / or free space).

[0093] Lens grating structures 510A-510N can be configured to receive coherent radiation from radiation source 502, generate a focused coherent radiation beam based on the coherent radiation, and propagate the focused coherent radiation beam toward multiple regions on the surface of the substrate for use in particle inspection and other metrology techniques. In response to a region irradiated by the focused coherent radiation beam, lens grating structures 510A-510N can be configured to receive photons scattered from that region and propagate the received photons to balanced photodetectors 512A-512N.

[0094] like Figure 5As shown, each of the balanced photodetectors 512A-512N can be optically coupled (e.g., via four channels such as waveguides) to each of the four quadrants of a corresponding lens grating structure in the lens grating structures 510A-510N. Each of the balanced photodetectors 512A-512N can be configured to measure photons received by a corresponding lens grating structure in the lens grating structures 510A-510N, and generate an electronic signal based on the measured photons for use in detecting particles located in a region on the surface of the substrate. Additionally or alternatively, each of the balanced photodetectors 512A-512N can be configured to generate an optical signal based on the measured photons to allow for faster data processing. In some aspects, each lens grating structure in the lens grating structures 510A-510N may include multiple regions (e.g., four quadrants), and each balanced photodetector in the balanced photodetectors 512A-512N may measure multiple groups of photons (e.g., four groups of photons) received by multiple regions (e.g., a first group of photons for the first quadrant, a second group of photons for the second quadrant, a third group of photons for the third quadrant, and a fourth group of photons for the fourth quadrant), and generate an electronic signal based on the measured multiple groups of photons, wherein each of the multiple groups of photons has been received by a corresponding region of the lens grating structure.

[0095] In some aspects, a balanced photodetector can have two regions for measuring photons. In some aspects, the electronic signal can indicate the difference between the photons measured on the left side of the balanced photodetector and the photons measured on the right side. If no particles are present in the regions scanned by a focused coherent radiation beam, the response on the balanced photodetector can be symmetrical, and therefore the electronic signal can be substantially zero. If particles are scanned by a focused coherent radiation beam, a substantially non-zero electronic signal can be produced. Therefore, the balanced photodetector results in a higher signal-to-noise ratio. In some aspects, a quadrant detector with four regions can be used instead of a balanced photodetector, or a quadrant detector with four regions can be used in addition to a balanced photodetector. Four regions may be suitable if scanning is performed in the X direction (e.g., difference from left to right) and in the Y direction (e.g., difference from top to bottom).

[0096] In one example, a lens grating structure 510A can receive coherent radiation from a radiation source 502, generate a first focused coherent radiation beam based on the coherent radiation, and propagate the first focused coherent radiation beam toward a first region on the surface of the substrate. In response to illuminating the first region with the first focused coherent radiation beam, the lens grating structure 510A can receive photons scattered from the first region and transmit the received photons to a balanced photodetector 512A. The balanced photodetector 512A can measure the photons received by the lens grating structure 510A in each quadrant and generate a first electronic signal based on the measured photons.

[0097] In another example, the lens grating structure 510B can receive coherent radiation from the radiation source 502, generate a second focused coherent radiation beam based on the coherent radiation, and propagate the second focused coherent radiation beam toward a second region on the surface of the substrate. In response to illuminating the second region with the second focused coherent radiation beam, the lens grating structure 510B can receive photons scattered from the second region and transmit the received photons to a balanced photodetector 512B. The balanced photodetector 512B can measure the photons received by the lens grating structure 510B in each quadrant and generate a second electronic signal based on the measured photons.

[0098] In another example, the lens grating structure 510N can receive coherent radiation from the radiation source 502, generate an Nth focused coherent radiation beam (where N represents an integer value greater than 2) based on the coherent radiation, and propagate the Nth focused coherent radiation beam toward an Nth region on the surface of the substrate. In response to illuminating the Nth region with the Nth focused coherent radiation beam, the lens grating structure 510N can receive photons scattered from the Nth region and propagate the received photons to a balanced photodetector 512N. The balanced photodetector 512N can measure the photons received by each quadrant of the lens grating structure 510N and generate an Nth electronic signal based on the measured photons.

[0099] In some aspects, the controller may be electrically coupled to the balanced photodetectors 512A-512N and configured to receive electronic signals from the balanced photodetectors 512A-512N. In some aspects, a corresponding region illuminated by a corresponding lens grating structure in the lens grating structures 510A-510N may include particles, and the controller may be configured to detect particles based on electronic signals generated by the corresponding balanced photodetectors in the balanced photodetectors 512A-512N.

[0100] In some aspects, the particle inspection system 500 can perform detection by scanning a region of a substrate with one or more focused coherent radiation beams emitted by the lens grating structures 510A-510N. If particles are present, one or more electronic signals generated by the balanced photodetectors 512A-512N can change (e.g., become substantially non-zero), resulting in particle detection. For example, the particle inspection system 500 can use the lens grating structures 510A-510N to scan a region on the substrate surface with focused coherent radiation beams. The particle inspection system 500 can then use the balanced photodetectors 512A-512N to measure photons received by the lens grating structures 510A-510N and generate electronic signals based on the measured photons. In some aspects, if the value of the electronic signal is substantially zero, the particle inspection system 500 can use a controller to determine that the region corresponding to the electronic signal does not contain particles. In some aspects, if the value of the electronic signal changes from substantially zero to substantially non-zero, the particle inspection system 500 can use a controller to determine that the region corresponding to the electronic signal includes particles. Continuing this example, the particle inspection system 500 can use a controller to detect changes (e.g., from zero to non-zero) in one or more electronic signals generated by balanced photodetectors 512A-512N in response to irradiation of a region with a focused coherent radiation beam. The particle inspection system 500 can then use the controller to detect particles in the region associated with the changes in the one or more electronic signals.

[0101] In some aspects, the coherent radiation generated by radiation source 502 can be visible light (e.g., with a wavelength of about 400 nm), and particle inspection system 500 can use a controller to detect particles with sizes smaller than about 100 nm, about 100 nm, or larger than about 100 nm (e.g., 0.2 μm, 0.5 μm, 1 μm, 10 μm, or any other suitable particle size). For example, particle inspection system 500 can utilize particle inspection techniques including: (i) emitting and receiving light through a high numerical aperture objective lens; (ii) utilizing multiple k-vectors implemented by lens grating structures 510A-510N; and (iii) utilizing coherent light. This particle inspection technique can be particularly suitable for detecting very small particles (e.g., smaller than about 100 nm, such as 50 nm, 40 nm, etc.). Furthermore, the source power required for detecting small particles can be relatively low (e.g., compared to dark-field inspection). For example, the expected dose for each lens grating structure used in this particle inspection technique can be less than about 1.0 millijoules per square millimeter (mJ / mm²). 2 ).

[0102] In some aspects, incident light (e.g., coherent radiation at 400 nm) provided by radiation source 502 can be coupled into the chip via fiber-to-grating coupling 506. The incident light can reach lens grating structures 510A-510N via waveguides 508A-508N, respectively. Each lens grating structure in lens grating structures 510A-510N can consist of gratings with variable line spacing to focus the light (e.g., “lensing”). Subsequently, light scattered by the sample under inspection can be collected through the same lens grating structures (e.g., a black waveguide associated with the incident light; a gray waveguide associated with the scattered light). Each lens grating structure in lens grating structures 510A-510N can be divided into four regions to obtain a differential signal from the scattered light. Multiple parallel lens grating structures 510A-510N provided in an array or checkerboard pattern can allow for the inspection of larger areas in a single scan motion.

[0103] Figure 6 This is a schematic diagram showing a side view of a particle inspection system 600 according to some aspects of this disclosure. In some aspects, the particle inspection system 600 or any part thereof can be implemented using the following: [reference needed] Figure 4 The described reference particle inspection system 400 refers to any of the structures, components, features, or technologies described; reference Figure 5 The particle inspection system 500 is described; Reference Figure 8 The example computing system 800 described; any of the systems, structures, components, features, or techniques described in U.S. Provisional Patent Application No. 63 / 043,543, filed June 24, 2020, entitled “Self-Referencing Integrated Alignment Sensor” (which is incorporated herein by reference in its entirety); any other suitable structures, components, features, or techniques; any part thereof; or any combination thereof.

[0104] like Figure 6 As shown, the particle inspection system 600 may include a radiation source 602 (e.g., a laser source), an optical fiber 604, an optical fiber-to-grating coupling 606, a waveguide 608, a lens-grating structure 610, a balanced photodetector 612, and a controller (not depicted). In some aspects, the particle inspection system 600 may be an integrated optical parallel inspection system. In some aspects, Figure 6 Some or all of the components shown can be housed in a single-chip, Si3N4-based particle inspection device. In an illustrative and non-limiting example, the fiber-to-grating coupling 606, waveguide 608, lens grating structure 610, and balanced photodetector 612 can be housed on a single chip.

[0105] Radiation source 602 can be configured to generate coherent radiation (e.g., with a wavelength of approximately 400 nm) and transmit the coherent radiation via optical fiber 604 to fiber-to-grating coupling 606, and via waveguide 608 to lens grating structure 610. Lens grating structure 610 can be configured to receive the coherent radiation from radiation source 602, generate a focused coherent radiation beam 614 based on the coherent radiation, and direct the focused coherent radiation beam 614 toward a region of the substrate surface for use in particle inspection and other metrology techniques. In response to the region irradiated by the focused coherent radiation beam 614, lens grating structure 610 can be configured to receive photons scattered from that region and transmit the received photons to balanced photodetector 612.

[0106] The balanced photodetector 612 can be optically coupled (e.g., via four channels such as waveguides) to each of the four quadrants of the lens grating structure 610. The balanced photodetector 612 can be configured to measure photons received by the lens grating structure 610 and generate an electronic signal based on the measured photons for use in detecting particles in a region located on the surface of the substrate. Additionally or alternatively, the balanced photodetector 612 can be configured to generate an optical signal based on the measured photons to allow for faster data processing. In some aspects, the lens grating structure 610 can include multiple regions (e.g., four quadrants), and the balanced photodetector 612 can measure multiple sets of photons (e.g., four sets of photons) received by multiple regions (e.g., a first set of photons for a first quadrant, a second set of photons for a second quadrant, a third set of photons for a third quadrant, and a fourth set of photons for a fourth quadrant), and generate an electronic signal based on the measured multiple sets of photons, wherein each of the multiple sets of photons has been received by a corresponding region of the lens grating structure 610.

[0107] In some aspects, the balanced photodetector 612 may have two regions for measuring photons. In some aspects, the electronic signal may indicate the difference between the photons measured on the left side of the balanced photodetector 612 and the photons measured on the right side of the balanced photodetector 612. If no particles are present in the region scanned by the focused coherent radiation beam 614, the response on the balanced photodetector 612 may be symmetrical, and thus the electronic signal may be substantially zero. If particles are scanned by the focused coherent radiation beam 614, the response on the balanced photodetector 612 may be asymmetrical, and thus the electronic signal may be substantially non-zero. Therefore, the balanced photodetector 612 results in a higher signal-to-noise ratio. In some aspects, a quadrant detector with four regions may be used instead of the balanced photodetector 612, or a quadrant detector with four regions may be used in addition to the balanced photodetector 612 (e.g., for two-dimensional scanning performed in the X and Y directions).

[0108] In some aspects, the controller may be electrically coupled to the balanced photodetector 612 and configured to receive electronic signals from the balanced photodetector 612. In some aspects, the area irradiated by the focused coherent radiation beam 614 may include particles, and the controller may be configured to detect particles based on the electronic signals generated by the balanced photodetector 612. In some aspects, the particle inspection system 600 may perform detection by scanning an area of ​​the substrate with the focused coherent radiation beam 614 emitted by the lens grating structure 610. If particles are present, the electronic signals generated by the balanced photodetector 612 may be altered (e.g., become substantially non-zero), resulting in particle detection.

[0109] In some respects, the focused coherent radiation beam 614 generated by the lens grating structure 610 can have a pencil beam shape, such as Figure 6 As shown. In some aspects, a pencil beam can be generated by using a one-dimensional focusing element (e.g., a grating structure), allowing a larger area to be examined in a single scan move. For example, the lens grating structure 610 can be adjusted to act as a phased optical array, which allows the focused coherent radiation beam 614 to move laterally as it is scanned, and thus allows even larger surfaces to be examined in a single scan.

[0110] In several embodiments, the particle inspection system 600 may include N lens grating structures, each coupled to N balanced photodetectors, where N represents an integer value greater than 1, to allow for parallel inspection with higher throughput. The N lens grating structures may, for example, be aligned such that pencil beams generated by the N lens grating structures overlap at their ends to produce a signal beam with a longer length than a single beam. Additionally, the N lens grating structures may be offset relative to each other in the scanning direction to produce, for example, a front-back-front-back-front-back pattern.

[0111] In an illustrative and non-limiting example, the lens grating structure 610 may be the Nth lens grating structure, and the balanced photodetector 612 may be the Nth balanced photodetector. The Nth lens grating structure may receive coherent radiation from the radiation source 602, generate an Nth focused coherent radiation beam based on the coherent radiation, and propagate the Nth focused coherent radiation beam toward an Nth region on the surface of the substrate. In response to illuminating the Nth region with the Nth focused coherent radiation beam, the Nth lens grating structure may receive photons scattered from the Nth region and propagate the received photons to the Nth balanced photodetector. The Nth balanced photodetector may measure the photons received by each quadrant of the Nth lens grating structure and generate an Nth electronic signal based on the measured photons.

[0112] Exemplary process for detecting particles

[0113] Figure 7 This is an example method 700 for detecting particles, based on some aspects of this disclosure or its portions(s). The operation described with reference to example method 700 can be performed by or according to any system, apparatus, component, technique, or combination thereof described herein, such as with reference to Figures 1-6 above and below. Figure 8 The operations described.

[0114] In operation 702, the method may include receiving coherent radiation from a radiation source (e.g., radiation source 502, 602) via a grating structure (e.g., lens grating structures 510A-510N, 610). In some aspects, the reception of coherent radiation may be accomplished using suitable optical, electrical, mechanical, or other methods, and includes [further details to be added] with reference to Figures 1-6 above and below. Figure 8 Any aspect or combination of aspects described to receive coherent radiation.

[0115] In operation 704, the method may include generating a focused coherent radiation beam based on coherent radiation from a grating structure. In some aspects, the generation of the focused coherent radiation beam may include generating a focused coherent radiation beam having a pencil-beam shape from a grating structure (e.g., as...). Figure 6 (Referring to the focused coherent radiation beam 614 depicted in the middle). In some respects, the generation of the focused coherent radiation beam can be accomplished using suitable optical, electrical, mechanical or other methods, including according to Figures 1-6 above and below. Figure 8 Any aspect or combination of aspects described herein may be used to generate a focused coherent radiation beam.

[0116] In operation 706, the method may include transmitting a focused coherent radiation beam toward a region of the substrate surface via a grating structure (e.g., irradiating the region with the focused coherent radiation beam). In some aspects, the transmission of the focused coherent radiation beam may be accomplished using suitable optical, electrical, mechanical, or other methods, and includes, with reference to Figures 1-6 above and below... Figure 8 Any aspect or combination of aspects described herein is used to transmit a focused coherent radiation beam.

[0117] In operation 708, the method may include: in response to irradiating the region with a focused coherent radiation beam, receiving photons scattered from the region by a grating structure. In some aspects, the reception of photons may be accomplished using suitable optical, electrical, mechanical, or other methods, and includes, with reference to Figures 1-6 above and below... Figure 8 Any aspect or combination of aspects described to receive photons.

[0118] In operation 710, the method may include measuring photons received by the grating structure using a photodetector (e.g., balanced photodetectors 512A-512N, 612). In some aspects, the measurement of photons may be performed using suitable optical, electrical, mechanical, or other methods, and includes [the measurement is performed] according to Figures 1-6 above and below. Figure 8 Any aspect or combination of aspects described is used to measure photons.

[0119] In operation 712, the method may include generating an electronic signal by a photodetector and based on measured photons for use in detecting particles in a region located on the surface of a substrate. Additionally or alternatively, the method may include generating an optical signal by a photodetector based on measured photons to allow for faster data processing. In some aspects, the generation of the electronic or optical signal may be accomplished using suitable optical, electrical, mechanical, or other methods, and includes [further details regarding the method described in Figures 1-6 above and below]. Figure 8 Any aspect or combination of aspects described herein can be used to generate an electronic signal.

[0120] In operation 714, the method may include detecting particles in a region based on electronic signals by a controller (e.g., controller 430, example computing system 800). For example, the region may include particles, and the method may further include: scanning the surface of a substrate with a focused coherent radiation beam by a grating structure; detecting changes in the electronic signal by the controller in response to irradiation of the region with the focused coherent radiation beam; and detecting particles by the controller based on changes in the electronic signal. In some aspects, the coherent radiation may have a wavelength of about 400 nm, and the size of the detected particles may be less than about 100 nm. In some aspects, particle detection may be accomplished using suitable optical, electrical, mechanical, or other methods, and includes [following the examples in Figures 1-6 above and below]. Figure 8 Any aspect or combination of aspects described can be used to detect particles.

[0121] Optionally, in some aspects, the grating structure may include multiple regions, and the method may further include: receiving multiple sets of photons scattered from a region by the multiple regions of the grating structure in response to irradiation of the region with a focused coherent radiation beam; measuring the multiple sets of photons received by the multiple regions by a photodetector; and generating an electronic signal by the photodetector based on the measured multiple sets of photons. In these aspects, the multiple sets of photons may include the photons measured at operation 710, and each set of photons may have already been received by a corresponding region of the grating structure.

[0122] Optionally, in some aspects, the method may further include: receiving a corresponding portion of coherent radiation from a radiation source by each of a plurality of grating structures including grating structures; generating a corresponding focused coherent radiation beam by each of the plurality of grating structures based on the corresponding portion of the coherent radiation; transmitting the corresponding focused coherent radiation beam toward a corresponding region of the surface of the substrate by each of the plurality of grating structures; receiving a corresponding photon scattered from the corresponding region in response to irradiating the corresponding region with the corresponding focused coherent radiation beam by each of the plurality of grating structures; measuring the corresponding photon received by the corresponding grating structure by each of a plurality of photodetectors including photodetectors; and generating a corresponding electronic signal by each of the plurality of photodetectors and based on the measured photon for use in detecting particles located in a region on the surface of the substrate.

[0123] Example computing system

[0124] The aspects of this disclosure can be implemented in hardware, firmware, software, or any combination thereof. The aspects of this disclosure can also be implemented as instructions stored on a machine-readable medium that can be read and executed by one or more processors. A machine-readable medium can include any mechanism for storing or transmitting information in a machine-readable (e.g., computing device) form. For example, a machine-readable medium can include read-only memory (ROM); random access memory (RAM); disk storage media; optical storage media; flash memory devices; electrical, optical, acoustic, or other forms of propagation signals (e.g., carrier waves, infrared signals, digital signals, etc.). Further, firmware, software, routines, instructions, and combinations thereof can be described herein as performing certain actions. However, it should be understood that such description is merely for convenience, and such actions are actually generated by a computing device, processor, controller, or other device executing the firmware, software, routines, instructions, or combinations thereof, and in doing so, cause an actuator or other device (e.g., a servo motor, a robotic device) to interact with the physical world.

[0125] For example, one or more computing systems (such as...) can be used. Figure 8 The example computing system 800 shown implements these aspects. The example computing system 800 may be a dedicated computer capable of performing the functions described herein, such as: [reference needed] Figure 4 The particle inspection system 400 described; Reference Figure 5 The particle inspection system 500 is described; Reference Figure 6The particle inspection system 600 described; any other suitable system, subsystem, or component; or any combination thereof. Example computing system 800 may include one or more processors (also referred to as a central processing unit or CPU), such as processor 804. Processor 804 is connected to communication infrastructure 806 (e.g., a bus). Example computing system 800 may also include multiple user input / output devices 803 (such as monitors, keyboards, pointing devices, etc.) that communicate with communication infrastructure 806 via multiple user input / output interfaces 802. Example computing system 800 may also include main memory 808 (e.g., one or more main storage devices), such as random access memory (RAM). Main memory 808 may include one or more levels of cache. Main memory 808 already stores control logic (e.g., computer software) and / or data.

[0126] The example computing system 800 may also include secondary storage 810 (e.g., one or more secondary storage devices). Secondary storage 810 may include, for example, a hard disk drive 812 and / or a removable storage drive 814. The removable storage drive 814 may be a floppy disk drive, tape drive, optical disk drive, optical storage device, tape backup device, and / or any other storage device drive.

[0127] Removable storage drive 814 can interact with removable storage unit 818. Removable storage unit 818 includes a computer-usable or readable storage device on which computer software (control logic) and / or data are stored. Removable storage unit 818 can be a floppy disk, magnetic tape, optical disc, DVD, optical storage disc, and / or any other computer data storage device. Removable storage drive 814 reads from and / or writes to removable storage unit 818.

[0128] According to some aspects, the auxiliary storage 810 may include other components, tools, or other methods for allowing computer programs and / or other instructions and / or data to be accessed by the example computing system 800. Such components, tools, or other methods may include, for example, removable storage unit 822 and interface 820. Examples of removable storage unit 822 and interface 820 may include a program box and box interface (such as those found in video game devices), a removable memory chip (such as EPROM or PROM) and associated sockets, a memory stick and USB port, a memory card and associated memory card slot, and / or any other removable storage unit and associated interface.

[0129] The example computing system 800 may also include a communication interface 824 (e.g., one or more network interfaces). The communication interface 824 enables the example computing system 800 to communicate and interact with any combination of remote devices, remote networks, remote entities, etc. (collectively and individually referred to as remote device 828). For example, the communication interface 824 may allow the example computing system 800 to communicate with the remote device 828 via a communication path 826, which may be wired and / or wireless, and may include any combination of LAN, WAN, Internet, etc. Control logic, data, or both may be transmitted to and from the example computing system 800 via the communication path 826.

[0130] The operations described in the foregoing aspects of this disclosure can be implemented in a wide variety of configurations and architectures. Therefore, some or all of the operations described in the foregoing aspects can be performed in hardware, software, or both. In some aspects, a tangible, non-transient means or article of manufacture includes a tangible, non-transient computer-usable or readable medium having control logic (software) stored thereon, also referred to herein as a computer program product or program storage device. This includes, but is not limited to, example computing system 800, main memory 808, secondary memory 810, and removable storage units 818 and 822, and tangible articles of manufacture embodying any combination thereof. When executed by one or more data processing devices (such as computing system 800), such control logic causes such data processing devices to operate as described herein.

[0131] Based on the teachings contained in this disclosure, it will be clear to those skilled in the art(s) that different methods are used... Figure 8 It will be apparent from the data processing apparatus, computer system, and / or computer architecture shown that various aspects of this disclosure can be made and used. In particular, various aspects of this disclosure can be operated using software, hardware, and / or operating system implementations different from those described herein.

[0132] The embodiments may be further described using the following terms:

[0133] 1. A system comprising:

[0134] The radiation source is configured to generate coherent radiation;

[0135] A grating structure is optically coupled to the radiation source and configured as follows:

[0136] Receive coherent radiation from this radiation source.

[0137] Based on this coherent radiation, a focused coherent radiation beam is generated.

[0138] The focused coherent radiation beam is transmitted toward the region of the substrate surface, and

[0139] In response to illumination of the region by the focused coherent radiation beam, photons scattered from the region are received; and

[0140] A photodetector, optically coupled to the grating structure, is configured as follows:

[0141] The photon received by the grating structure is measured, and

[0142] Based on the fact that what is being measured is the photon-generated electron signal.

[0143] 2. The system according to Clause 1, wherein:

[0144] This region includes particles; and

[0145] The system also includes a controller coupled to the photodetector and configured to:

[0146] Receive the electronic signal from the photodetector, and

[0147] The particle is detected based on this electronic signal.

[0148] 3. The system according to Clause 2, wherein:

[0149] The radiation source includes a laser source configured to emit the coherent radiation;

[0150] This coherent radiation has a wavelength of approximately 400 nanometers; and

[0151] The particle is smaller than approximately 100 nanometers.

[0152] 4. The system according to Clause 1, wherein:

[0153] The grating structure comprises multiple regions;

[0154] The photodetector is configured as follows:

[0155] Measure multiple sets of photons received from these multiple regions, and

[0156] The electronic signal is generated based on the measured multiple sets of photons;

[0157] The multiple groups of photons include this photon; and

[0158] Each of the multiple sets of photons has been received by the corresponding region of the grating structure.

[0159] 5. The system according to Clause 4, wherein:

[0160] A grating structure is a lens grating structure that includes four quadrants;

[0161] Each of these multiple regions corresponds to a specific quadrant of the lens grating structure; and

[0162] The photodetector is a balanced photodetector, which is coupled to each quadrant of the lens grating structure through corresponding channels.

[0163] 6. The system according to Clause 1 further includes:

[0164] A plurality of grating structures, including the grating structure, wherein each of the plurality of grating structures is optically coupled to the radiation source and configured as follows:

[0165] Receive the corresponding portion of the coherent radiation from the radiation source.

[0166] Based on the corresponding portion of this coherent radiation, a corresponding focused coherent radiation beam is generated.

[0167] The corresponding focused coherent radiation beam is transmitted toward the corresponding region on the surface of the substrate, and

[0168] In response to the corresponding illumination of the corresponding region by the corresponding focused coherent radiation beam, the corresponding photon scattered from the corresponding region is received; and

[0169] A plurality of photodetectors, including the photodetector, wherein each of the plurality of photodetectors is optically coupled to a corresponding grating structure and is configured as follows:

[0170] Measure the corresponding photon received by the corresponding grating structure, and

[0171] The corresponding electronic signal is generated based on the measured photon.

[0172] 7. The system according to Clause 1, wherein the grating structure is configured to generate the focused coherent radiation beam having a pencil beam shape.

[0173] 8. A single-piece inspection device, comprising:

[0174] The receiver is configured to receive coherent radiation from the radiation source;

[0175] A focusing structure, optically coupled to the receiver, is configured as follows:

[0176] Based on this coherent radiation, a focused coherent radiation beam is generated.

[0177] The focused coherent radiation beam is transmitted toward the region of the substrate surface, and

[0178] In response to the illumination of the region by the focused coherent radiation beam, the region receives photons scattered from the region; and

[0179] A photodetector, optically coupled to the focusing structure, is configured as follows:

[0180] The photon received by the focusing structure is measured, and

[0181] The measured photon generates an electronic signal.

[0182] 9. The single-piece inspection device as described in Clause 8, wherein:

[0183] This region includes particles; and

[0184] The single-chip inspection device also includes a controller coupled to the photodetector and configured to:

[0185] Receive the electronic signal from the photodetector, and

[0186] The particle is detected based on this electronic signal.

[0187] 10. The single-piece inspection device according to Clause 9, wherein:

[0188] This coherent radiation has a wavelength of approximately 400 nanometers; and

[0189] The particle is smaller than approximately 100 nanometers.

[0190] 11. The single-piece inspection device according to Clause 8, wherein:

[0191] This focused structure includes multiple regions;

[0192] The photodetector is configured as follows:

[0193] Measure multiple sets of photons received from these multiple regions, and

[0194] The electronic signal is generated based on the measured multiple sets of photons;

[0195] The multiple groups of photons include this photon; and

[0196] Each of the multiple photons has been received by the corresponding region of the focusing structure.

[0197] 12. The single-piece inspection device according to Clause 11, wherein:

[0198] The focusing structure is a lens grating structure that includes four quadrants;

[0199] Each of these multiple regions corresponds to a specific quadrant of the lens grating structure; and

[0200] The photodetector is a balanced photodetector, which is coupled to each quadrant of the lens grating structure through corresponding channels.

[0201] 13. The single-piece inspection equipment according to Clause 8 also includes:

[0202] Multiple focusing structures, including the focusing structure, wherein each of the multiple focusing structures is optically coupled to the radiation source and is configured as follows:

[0203] Receive the corresponding portion of the coherent radiation from the radiation source.

[0204] Based on the corresponding portion of this coherent radiation, a corresponding focused coherent radiation beam is generated.

[0205] The corresponding focused coherent radiation beam is transmitted toward the corresponding region on the surface of the substrate, and

[0206] In response to the corresponding illumination of the corresponding region by the corresponding focused coherent radiation beam, the corresponding photon scattered from the corresponding region is received; and

[0207] A plurality of photodetectors, including the photodetector, wherein each of the plurality of photodetectors is optically coupled to a corresponding focusing structure and is configured as follows:

[0208] The corresponding photon received by the corresponding focusing structure is measured, and

[0209] The corresponding electronic signal is generated based on the measured photon.

[0210] 14. The monolithic inspection apparatus according to Clause 8, wherein the focusing structure is configured to generate the focused coherent radiation beam having a pencil beam shape.

[0211] 15. A method comprising:

[0212] The grating structure receives coherent radiation from the radiation source;

[0213] The grating structure generates a focused coherent radiation beam based on the coherent radiation.

[0214] The grating structure transmits the focused coherent radiation beam toward the surface of the substrate.

[0215] In response to illuminating the region with the focused coherent radiation beam, the grating structure receives photons scattered from the region;

[0216] The photon received by the grating structure is measured by a photodetector; and

[0217] The photodetector generates an electronic signal based on the measured photon.

[0218] 16. The method according to Clause 15, wherein:

[0219] This region includes particles; and

[0220] The method also includes:

[0221] The grating structure uses the focused coherent radiation beam to scan the surface of the substrate;

[0222] In response to irradiating the region with the focused coherent radiation beam, the controller detects changes in the electronic signal; and

[0223] The controller detects the particle based on changes in the electronic signal.

[0224] 17. The method according to Clause 16, wherein:

[0225] This coherent radiation has a wavelength of approximately 400 nanometers; and

[0226] The particle is smaller than approximately 100 nanometers.

[0227] 18. The method according to Clause 15, wherein:

[0228] The grating structure comprises multiple regions;

[0229] The method also includes:

[0230] In response to irradiating the region with the focused coherent radiation beam, multiple regions of the grating structure receive multiple sets of photons scattered from the region;

[0231] The photodetector measures the multiple sets of photons received by the multiple regions, and the photodetector generates the electronic signal based on the measured multiple sets of photons;

[0232] The multiple groups of photons include this photon; and

[0233] Each of the multiple sets of photons has been received by the corresponding region of the grating structure.

[0234] 19. The method described under Clause 15 further includes:

[0235] Each of a plurality of grating structures, including the grating structure, receives a corresponding portion of the coherent radiation from the radiation source;

[0236] Each of the plurality of grating structures generates a corresponding focused coherent radiation beam based on the corresponding portion of the coherent radiation;

[0237] Each of the plurality of grating structures transmits the corresponding focused coherent radiation beam toward a corresponding region on the surface of the substrate;

[0238] Each of the plurality of grating structures receives a corresponding photon scattered from the corresponding region in response to irradiating the corresponding region with the corresponding focused coherent radiation beam;

[0239] The photon received by the corresponding grating structure is measured by each of a plurality of photodetectors including the photodetector; and

[0240] Each of the plurality of photodetectors generates a corresponding electronic signal based on the measured corresponding photon.

[0241] 20. The method according to Clause 15, wherein generating the focused coherent radiation beam comprises generating the focused coherent radiation beam having a pencil beam shape from the grating structure.

[0242] While specific reference may be made herein to the use of lithography apparatus in IC manufacturing, it should be understood that the lithography apparatus described herein may have other applications, such as the fabrication of integrated optical systems, and the guiding and inspection of patterns for magnetic domain memory, flat panel displays, LCDs, 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 “wafer” or “die” herein may be considered synonymous with the more general terms “substrate” or “target portion,” respectively. The substrate referred to herein may be processed before or after exposure in, for example, a particle inspection unit, a tracking unit (a tool for applying a resist layer to the substrate and developing the exposed resist), a metering unit, or a combination thereof. Where applicable, the disclosure herein may be applied to such and other substrate processing tools. Furthermore, for example, to produce multilayer ICs, the substrate may be processed more than once, such that the term “substrate” as used herein may also refer to a substrate that already contains multiple processed layers.

[0243] It should be understood that the wording or terminology used herein is for descriptive rather than limiting purposes, and that the terminology or terminology used herein will be interpreted by those skilled in the art based on the teachings herein.

[0244] As used in this article, the term "substrate" describes the material on which a layer of material is added. In some respects, the substrate itself may be patterned, and the material added on top of it may also be patterned, or may be left unpatterned.

[0245] The examples disclosed herein are illustrative of embodiments of this disclosure and not limiting. Other suitable modifications and adjustments to various conditions and parameters commonly encountered in the art (which will be apparent to those skilled in the art) are within the spirit and scope of this disclosure.

[0246] While specific aspects of this disclosure have been described above, it should be understood that these aspects may be implemented in ways other than those described. The description is not intended to limit the embodiments of this disclosure.

[0247] It should be understood that the detailed description section, and not the background, summary, and abstract sections, is intended to be used to interpret the claims. The summary and abstract sections may set forth one or more, but not all, exemplary embodiments conceived by the inventors(s), and are therefore not intended to limit the embodiments and the appended claims in any way.

[0248] The above description, using functional building blocks illustrating implementations of specified functions and their relationships, has described some aspects of this disclosure. For ease of description, the boundaries of these functional building blocks are arbitrarily defined herein. Alternative boundaries can be defined as long as the specified functions and their relationships are properly performed.

[0249] The foregoing description of specific aspects of this disclosure will fully reveal the general nature of the aspects, enabling others to readily modify and / or adapt these specific aspects for various applications by applying the knowledge of those skilled in the art, without departing from the general conception of this disclosure, without excessive experimentation. Therefore, based on the teachings and guidance presented herein, such modifications and adjustments are intended to be within the meaning and scope of equivalents of the disclosed aspects.

[0250] The breadth and scope of this disclosure should not be limited by any of the foregoing exemplary aspects or embodiments, but should be defined solely by the appended claims and their equivalents.

Claims

1. A system for generating electronic signals, comprising: The radiation source is configured to generate coherent radiation; A grating structure, optically coupled to the radiation source, is configured as follows: Receive the coherent radiation from the radiation source. Based on the coherent radiation, a focused coherent radiation beam is generated. The focused coherent radiation beam is transmitted toward a region of the substrate surface, wherein the grating structure consists of gratings with variable line spacing and is coupled to the radiation source via a waveguide, and In response to illumination of the region by the focused coherent radiation beam, photons scattered from the region are received; as well as A photodetector, optically coupled to the grating structure, is configured to: Measure the photons received by the grating structure, and The measured photons generate electronic signals.

2. The system according to claim 1, wherein: The region includes particles; and The system also includes a controller coupled to the photodetector and configured to: Receive the electronic signal from the photodetector, and The particles are detected based on the electronic signal.

3. The system according to claim 2, wherein: The radiation source includes a laser source configured to generate the coherent radiation; The coherent radiation has a wavelength of 400 nanometers; and The size of the particles is less than 100 nanometers.

4. The system according to claim 1, wherein: The grating structure includes multiple regions; The photodetector is configured as follows: Measure multiple sets of photons received by the multiple regions, and The electronic signal is generated based on the measured multiple sets of photons; The plurality of photons includes the photons; and Each of the multiple groups of photons has been received by the corresponding region of the grating structure.

5. The system according to claim 4, wherein: The grating structure is a lens grating structure that includes four quadrants; Each of the plurality of regions corresponds to a specific quadrant of the lens grating structure; as well as The photodetector is a balanced photodetector, which is coupled to each quadrant of the lens grating structure through corresponding channels.

6. The system according to claim 1, further comprising: A plurality of grating structures, including the grating structures, wherein each of the plurality of grating structures is optically coupled to the radiation source and is configured to: Receive the corresponding portion of the coherent radiation from the radiation source. Based on the corresponding portion of the coherent radiation, a corresponding focused coherent radiation beam is generated. The corresponding focused coherent radiation beam is transmitted toward the corresponding region of the surface of the substrate, and In response to the corresponding illumination of the corresponding region by the corresponding focused coherent radiation beam, the corresponding photon scattered from the corresponding region is received; as well as A plurality of photodetectors, including the photodetectors, wherein each of the plurality of photodetectors is optically coupled to a corresponding grating structure and is configured to: Measure the corresponding photons received by the corresponding grating structure, and Based on the measured corresponding photons, a corresponding electronic signal is generated.

7. The system of claim 1, wherein the grating structure is configured to generate the focused coherent radiation beam having a pencil beam shape.

8. A method for generating an electronic signal, comprising: Coherent radiation from the radiation source is received via a waveguide coupled to the radiation source and through a grating structure, wherein the grating structure is composed of gratings with variable line spacing. The grating structure generates a focused coherent radiation beam based on the coherent radiation; The grating structure transmits the focused coherent radiation beam toward the surface of the substrate. In response to irradiating the region with the focused coherent radiation beam, the grating structure receives photons scattered from the region; The photons received by the grating structure are measured by a photodetector; as well as An electronic signal is generated by a photodetector based on the measured photons.

9. The method according to claim 8, wherein: The region includes particles; and The method further includes: The surface of the substrate is scanned by the grating structure using the focused coherent radiation beam; In response to irradiating the region with the focused coherent radiation beam, the controller detects changes in the electronic signal; and The controller detects the particles based on the changes in the electronic signal.

10. The method of claim 9, wherein: The coherent radiation has a wavelength of 400 nanometers; and The size of the particles is less than 100 nanometers.

11. The method according to claim 8, wherein: The grating structure includes multiple regions; The method further includes: In response to irradiating the region with the focused coherent radiation beam, the plurality of regions of the grating structure receive multiple sets of photons scattered from the region; The photodetector measures the multiple sets of photons received by the multiple regions, and The photodetector generates the electronic signal based on the measured multiple sets of photons; The plurality of photons includes the photons; and Each of the multiple groups of photons has been received by the corresponding region of the grating structure.

12. The method according to claim 8, further comprising: Each of a plurality of grating structures, including the grating structure, receives a corresponding portion of the coherent radiation from the radiation source; Each of the plurality of grating structures generates a corresponding focused coherent radiation beam based on the corresponding portion of the coherent radiation; Each of the plurality of grating structures transmits the corresponding focused coherent radiation beam toward a corresponding region of the surface of the substrate; In response to irradiating the corresponding region with the corresponding focused coherent radiation beam, each of the plurality of grating structures receives the corresponding photon scattered from the corresponding region; Each of a plurality of photodetectors, including the photodetector, measures the corresponding photon received by the corresponding grating structure; as well as Each of the plurality of photodetectors generates a corresponding electronic signal based on the measured corresponding photon.

13. The method of claim 8, wherein generating the focused coherent radiation beam comprises generating the focused coherent radiation beam having a pencil beam shape from the grating structure.

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