Generating alignment signals without dedicated alignment structures

Abstract

Generating alignment signals for alignment of features in a layer of a substrate as part of a semiconductor manufacturing process is described. The system and method is faster and produces more information than typical methods of generating alignment signals because it utilizes existing structures in a patterned semiconductor wafer instead of dedicated alignment structures. Features of the patterned semiconductor wafer (not dedicated alignment marks) are continuously scanned, the scanning including continuously irradiating the features with radiation and continuously detecting reflected radiation from the features. The scanning is performed perpendicular to the features, along one side of the features, or along both sides of the features.

Description

[Technical field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Provisional Patent Application No. 63 / 293,504, filed December 23, 2021, and is incorporated by reference in its entirety into this specification.

[0002] This description relates generally to generating alignment signals without the need for dedicated alignment structures. [Background technology]

[0003] Lithographic projection apparatus can be used, for example, in the manufacture of integrated circuits (ICs). A patterning device (e.g. a mask) may contain or provide a pattern ("design layout") corresponding to an individual layer of the IC, which can be transferred onto a target portion (e.g. comprising one or more dies) on a substrate (e.g. a silicon wafer) that is coated with a layer of radiation-sensitive material ("resist"), such as by irradiating the target portion through the pattern on the patterning device. Typically, a single substrate will contain several adjacent target portions onto which the lithographic projection apparatus transfers the pattern, one at a time. In one type of lithographic projection apparatus, the pattern of the entire patterning device is transferred onto one target portion in one step. Such an apparatus is commonly referred to as a stepper. In another apparatus, commonly referred to as a step-and-scan apparatus, the projection beam scans the patterning device in a predetermined reference direction (the "scan" direction), while the substrate is moved synchronously parallel or anti-parallel to this reference direction. Different portions of the pattern on the patterning device are transferred progressively onto one target portion. Generally, a lithographic projection apparatus will have a demagnification ratio M (e.g. 4), so the speed F at which the substrate moves will be 1 / M times the speed at which the projection beam scans the patterning device. More information on lithographic devices as described herein can be gleaned, for example, from U.S. Patent No. 6,046,792, which is incorporated herein by reference.

[0004]

[0004] Before transferring the pattern from the patterning device to the substrate, the substrate may undergo various procedures such as priming, resist coating, and a soft bake. After exposure, the substrate may be subjected to other procedures ("post-exposure procedures") such as a post-exposure bake (PEB), development, a hard bake, and metrology / inspection of the transferred pattern. This sequence of procedures is used as a basis for manufacturing an individual layer of a device, e.g. an IC. The substrate may then undergo various processes such as etching, ion implantation (doping), metallization, oxidation, deposition, chemical-mechanical polishing, all of which are aimed at completing an individual layer of the device. If the device requires several layers, the entire procedure, or a variant thereof, is repeated for each layer. Eventually, a device will be present on each target portion on the substrate. These devices are then separated from one another by techniques such as dicing or sawing, so that the individual devices can be attached to a carrier or connected to pins.

[0005]

[0005] Thus, the manufacture of devices such as semiconductor devices typically involves processing a substrate (e.g., a semiconductor wafer) using multiple manufacturing processes to form various features and multiple layers of the device. Such layers and features are usually manufactured and processed using, for example, deposition, lithography, etch, deposition, chemical mechanical polishing, and ion implantation. Multiple devices may be manufactured into multiple dies on a substrate and then separated into individual devices. This device manufacturing process may be considered as a patterning process. A patterning process includes a patterning step, such as optical lithography and / or nanoimprint lithography, in which a patterning device is used in a lithography apparatus to transfer a pattern on the patterning device to a substrate, typically optionally accompanied by one or more associated pattern processing steps, such as developing a resist in a developer, baking the substrate using a bake tool, etching with the pattern using an etcher, deposition, etc.

[0006]

[0006] Lithography is a central process in the manufacture of devices such as ICs, where patterns formed on a substrate define the functional elements of devices such as microprocessors, memory chips, etc. Similar lithographic techniques are used in the formation of flat panel displays, micro-electromechanical systems (MEMS), and other devices.

[0007]

[0007] As semiconductor manufacturing processes continue to advance, the dimensions of functional elements are continually shrinking, while the number of functional elements, such as transistors, per device has been steadily increasing for decades, following a trend commonly referred to as "Moore's Law". In current technology, device layers are fabricated using lithographic projection apparatus that projects a design layout onto a substrate using illumination from a deep ultraviolet or extreme ultraviolet illumination source, producing individual functional elements with dimensions well below 100 nm, i.e., less than half the wavelength of radiation from the illumination source (e.g., a 193 nm illumination source).

[0008]

[0008] This process of printing features with dimensions smaller than the conventional resolution limit of the lithographic projection apparatus is commonly known as low k1 lithography, according to the resolution equation CD=k1×λ / NA, where λ is the wavelength of the radiation used (currently mostly 248 nm or 193 nm), NA is the numerical aperture of the projection optics in the lithographic projection apparatus, CD is the "critical dimension", i.e., the minimum feature size that is typically printed, and k1 is an empirical resolution factor. In general, the smaller k1 is, the more difficult it is to reproduce a pattern on a substrate that resembles the shape and dimensions planned by the designer to achieve a particular electrical functionality and performance. To overcome such difficulties, sophisticated fine-tuning steps are applied to the lithographic projection apparatus, the design layout, or the patterning device. These include, but are not limited to, optimization of NA and optical coherence settings, customized illumination schemes, the use of phase-shifting patterning devices, optical proximity correction (OPC, sometimes called "optical and process correction") in the design layout, or other methods commonly defined as "resolution enhancement techniques" (RET). Summary of the Invention

[0009]

[0009] Described herein is the generation of alignment signals for alignment of features in a layer of a substrate (e.g., a semiconductor wafer) that is part of a semiconductor manufacturing process. The systems and methods described herein are faster and generate more information than typical methods of generating alignment signals because they utilize existing structures in a patterned semiconductor wafer instead of dedicated alignment structures. Scanning is configured to run faster and generate more information than typical systems for generating metrology signals because the scan is performed on existing features rather than a series of individual alignment marks, continuously samples deformations over a large area of ​​the semiconductor wafer, and because the features do not span the interior of a device die and cause processing and / or packaging problems.

[0010]

[0010] As described below, features of a patterned semiconductor wafer (not dedicated alignment marks) may be successively scanned, which includes successively irradiating the features with radiation and successively detecting reflected radiation from the features. Scanning may be performed perpendicular to the features, along one side of the features, or along both sides of the features. As an example, a scribe line is an existing feature that may be utilized for alignment.

[0011] According to an embodiment, a system for generating a metrology signal is provided. The system includes a radiation source configured to irradiate a feature of a patterned substrate, the feature being distinct from a dedicated alignment structure. The system includes a sensor configured to detect reflected radiation from the feature. The system includes one or more processors configured to generate a metrology signal based on the detected reflected radiation from the feature. The metrology signal includes measurement information about the feature.

[0012] In some embodiments, the features include one or more structures in a patterned substrate that can provide a diffraction signal.

[0013]

[0013] In some embodiments, the feature is distinct from the dedicated alignment structure and other structures that are near the feature and within the illumination spot.

[0014]

[0014] In some embodiments, the irradiating and detecting include scanning, and the scanning is consecutive.

[0015]

[0015] In some embodiments, the feature is a structure capable of generating wide-angle diffraction and the scan is performed perpendicular to the feature, along one side of the feature when the spot size of the radiation is configured to cover one side of the line and / or edge feature, or along both sides of the feature when the spot size of the radiation is configured to cover both sides of the feature simultaneously.

[0016] In some embodiments, the feature comprises a line, an edge, or a series of fine pitch lines and / or edges, and the feature has a length that spans the area to be measured.

[0017] In some embodiments, the fine pitch has a pitch dimension of less than 1 micrometer.

[0018]

[0018] In some embodiments, the illumination and detection include scanning, which is configured to be performed faster and generate more information than typical systems for generating metrology signals because the scan is performed on the feature to continuously sample deformation over a large area of ​​a field or wafer rather than a series of individual alignment marks, and because the feature is configured to span the interior of a device die without causing processing and packaging issues.

[0019]

[0019] In some embodiments, the illumination and detection include scanning, which is configured to be performed faster and generate more information than typical systems for generating metrology signals because the scanning is performed on features in the patterned substrate instead of on dedicated alignment structures.

[0020]

[0020] In some embodiments, the illuminating and detecting includes scanning, and the metrology signal is calibrated based on a scan of the feature isolated from other surrounding structures.

[0021]

[0021] In some embodiments, the illuminating and detecting includes scanning, and the metrology signal is calibrated based on a vertical or parallel line scan.

[0022] In some embodiments, the metrology signal includes a signal from a parallel flank scan. The signal from the flank scan includes diffraction oriented perpendicular to the scan direction. The signal from the parallel flank scan includes a difference between a signal from a first scan of the feature and a signal from a second parallel scan of the feature.

[0023] In some embodiments, the metrology signal includes signals from two parallel flank scans for two corresponding features in two different regions. The signals from the two parallel flank scans include a difference between a first signal from a first parallel flank scan in a first region and a second signal from a second parallel flank scan in a second region. A given signal from a given parallel flank scan includes a difference between a signal from a first scan of the feature and a signal from a second parallel scan of the feature. The different regions include different dies on one substrate or the same die across different substrates.

[0024] In some embodiments, the illuminating and detecting includes scanning, and the scanning is performed at a predefined scan speed for a predefined sampling rate, the predefined scan speed and / or the predefined sampling rate being determined based on a size of the features.

[0025] In some embodiments, the predefined scan speed and / or the predefined sampling rate are adjustable based on the size of the feature.

[0026]

[0026] In some embodiments, the size of a feature that can be scanned is determined based on a ratio of a predetermined scan speed to a predefined sampling rate.

[0027] In some embodiments, the features include lines and / or edges, and the dedicated alignment structure includes a diffraction grating, and the line and / or edge features form part of the design layout separate from the diffraction grating.

[0028] In some embodiments, the metrology signal is an alignment signal or an overlay signal.

[0029] In some embodiments, the one or more processors are further configured to determine an alignment inspection position of the feature based on the metrology signal.

[0030] In some embodiments, the features are included in a layer of a substrate within a semiconductor device structure, and the one or more processors are further configured to adjust a semiconductor device manufacturing process based on the metrology signal.

[0031]

[0031] According to another embodiment, there is provided a method of generating a metrology signal, the method comprising irradiating a feature in a patterned substrate distinct from a dedicated alignment structure with radiation, detecting reflected radiation from the feature, and generating a metrology signal based on the detected reflected radiation from the feature, the metrology signal comprising measurement information about the feature.

[0032]

[0032] According to another embodiment, a non-transitory computer readable medium is provided having instructions which, when executed by a computer, cause operations including irradiating radiation to a feature in a patterned substrate that is distinct from a dedicated alignment structure, detecting reflected radiation from the feature, and generating a metrology signal containing measurement information about the feature based on the detected reflected radiation from the feature.

[0033] According to another embodiment, there is provided a method of generating alignment signals for alignment of features in a layer of a substrate as part of a semiconductor manufacturing process. The method is configured to run faster and generate more information than typical methods of generating alignment signals because the method is performed on existing structures in a patterned semiconductor wafer instead of dedicated alignment structures. The method includes continuously scanning line and / or edge features of the patterned semiconductor wafer, where the line and / or edge features are different from the dedicated alignment marks typically included in patterned semiconductor wafers. The scanning includes continuously irradiating the line and / or edge features with radiation and continuously detecting reflected radiation from the line and / or edge features. The scanning is performed perpendicular to the line and / or edge features, along one side of the line and / or edge features, or along both sides of the line and / or edge features. The method includes generating an alignment signal configured to be used to adjust the semiconductor manufacturing process based on the reflected radiation from the detected line and / or edge features. [Brief description of the drawings]

[0034]

[0034] The above aspects and other aspects and features will become apparent to those of ordinary skill in the art upon review of the following description of specific embodiments in conjunction with the accompanying figures.

[0035] [Figure 1] 1 illustrates a lithographic apparatus according to an embodiment; [Diagram 2]

[0036] 1 illustrates a schematic representation of an embodiment of a lithographic cell or cluster according to an embodiment. [Diagram 3]

[0037] 1 illustrates a schematic diagram of an exemplary inspection system according to an embodiment. [Figure 4]

[0038] 1 illustrates a schematic diagram of an exemplary metrology technique in accordance with an embodiment; [Diagram 5]

[0039] 1 illustrates a relationship between a radiation illumination spot and a metrology target of an inspection system in accordance with an embodiment. [Figure 6]

[0040] 1 illustrates a method for generating a metrology signal according to an embodiment. [Figure 7]

[0041] 1 shows a first possible version of a scan where the trajectory of the radiation beam is perpendicular to the feature according to an embodiment. [Figure 8]

[0042] 13 shows a second possible version of a scan in which the trajectory of the radiation beam follows one edge of the feature according to an embodiment. [Figure 9]

[0043] 13 shows a third possible version of a scan in which the trajectory of the radiation beam follows both edges of a feature according to an embodiment. [Figure 10]

[0044] 1 shows an equation defining the relationship between scan speed, sampling rate, and minimum resolvable feature size, according to one embodiment, where DF represents the cutoff frequency of the detection system electronics. [Figure 11]

[0045] 1 illustrates one possible example of metrology signal calibration according to an embodiment. [Figure 12]

[0046] 1 illustrates a flanking scan for an exemplary feature including a distorted single line structure, according to an embodiment. [Figure 13]

[0047] 13 shows a frank scan for a distorted line structure (eg, similar and / or the same as the line structure shown in FIG. 12), but including other surrounding pattern features ("clutter"), according to one embodiment. [Figure 14]

[0048] 1 shows data from the application of the paired (parallel) frank scan method described herein, according to an embodiment. [Figure 15]

[0049] FIG. 1 is a block diagram of an exemplary computer system according to an embodiment. [Figure 16]

[0050] 2 is a schematic diagram of a lithographic projection apparatus similar to FIG. 1 according to an embodiment; [Figure 17]

[0051] FIG. 17 is a more detailed diagram of the device of FIG. 16, according to an embodiment. [Figure 18]

[0052] FIG. 18 is a more detailed diagram of a source collector module of the apparatus of FIGS. 16 and 17 according to one embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0036]

[0053] In semiconductor device manufacturing, determining alignment typically involves determining the location of an alignment mark (or marks) in a layer of a semiconductor device structure. Alignment is typically determined by irradiating the alignment mark with radiation and comparing the characteristics of different diffraction orders of radiation reflected from the alignment mark. Similar techniques are used to measure overlay and / or other parameters. Smaller and smaller metrology (e.g., alignment, overlay, etc.) marks are required to accommodate smaller node sizes. Currently, metrology marks such as alignment marks may have resolution sizes as small as 40-50 μm. However, marks of 30 μm or less are desirable. Smaller marks make it easier to place multiple marks in a field with limited area, place marks within (e.g., half) scribe lines, place device structures in newly available areas no longer needed for alignment marks or other metrology marks, and / or place marks closer to the edge of the substrate. Unfortunately, there are currently no available technologies for creating marks this small that could be used for semiconductor manufacturing and / or other purposes (e.g., even if marks this small could be produced, they would encounter metrology, throughput, accuracy, compatibility, noise, pitch detectability, and / or other issues in the semiconductor manufacturing process).

[0037]

[0054] Advantageously, the present system and method utilizes existing structures in a patterned substrate (e.g., a semiconductor wafer) to generate metrology signals instead of dedicated alignment structures. The system and method described herein are faster and generate more information than typical methods. The scan is configured to run faster and generate more information than typical systems for generating metrology signals because it is performed on existing features instead of a series of individual alignment marks, continuously sampling deformations over a large area of ​​the substrate (semiconductor wafer), and because the features do not span inside the device die and cause processing and / or packaging problems. For example, currently, chip designers place alignment marks only on scribe lanes, not on product dies. This is primarily because 1) alignment marks only have temporary value and compete with space for transistors and other product features, and 2) mismatches in feature size and pattern density between the product and alignment marks often result in polishing steps that locally deform the product and alignment marks because the polishing step is most stable when the surface on which it acts is uniform. "Packaging" means that chip process designers need to fit many metrology targets (alignment, overlay, yield test structures) within the scribe lane, so they can't afford to waste space with large gaps between targets. So traditional alignment marks need to be large enough to avoid hitting surrounding structures as the illumination spot non-deterministically shifts position.

[0038]

[0055] Briefly, the description herein generally relates to semiconductor device manufacturing and patterning processes. More specifically, the following paragraphs describe systems and / or several components of related systems. As noted above, these systems and methods may be used, for example, to measure alignment or other operations in the manufacturing process of semiconductor devices.

[0039]

[0056] Although specific reference may be made herein to measuring the alignment of semiconductor devices and manufacturing integrated circuits (ICs), it should be understood that the description herein has many other possible applications. For example, it may be used to measure overlay and / or other parameters, and it may also be used in the manufacture of integrated optical systems such as magnetic domain memories, liquid crystal display panels, thin film magnetic heads, guidance and detection patterns. Those skilled in the art will appreciate that in the context of such alternative applications, the terms "reticle," "wafer," or "die" as used herein should be considered interchangeable with the more general terms "mask," "substrate," and "target portion," respectively.

[0040]

[0057] The term "projection optics" as used herein should be broadly interpreted to encompass various types of optical systems including, for example, refractive optics, reflective optics, apertures, and catadioptric optics. The term "projection optics" may also include components that collectively or alone operate according to any of these design types to direct, shape or control a projection beam of radiation. The term "projection optics" may include any optical component in a lithographic projection apparatus, regardless of where it is located on the optical path of the lithographic projection apparatus. Projection optics may include optical components for shaping, conditioning and / or projecting radiation from a radiation source before it passes through a patterning device, and / or optical components for shaping, conditioning and / or projecting radiation after it has passed through a patterning device. Generally, projection optics does not include a radiation source and a patterning device.

[0041]

[0058] Fig. 1 shows a schematic representation of an embodiment of a lithographic apparatus LA. The apparatus comprises an illumination system (illuminator) IL configured to condition a radiation beam B (e.g. UV, DUV or EUV radiation), a support structure (e.g. mask table) MT constructed to support a patterning device (e.g. mask) MA and connected to a first positioner PM configured to accurately position the patterning device according to certain parameters, a substrate table (e.g. wafer table) WT (e.g. WTa, WTb or both) configured to hold a substrate (e.g. resist coated wafer) W and coupled to a second positioner PW configured to accurately position the substrate according to certain parameters, and a projection system (e.g. refractive projection lens system) PS configured to project a pattern imparted to the radiation beam B by the patterning device MA onto a target portion C (e.g. comprising one or more dies, often referred to as a field) of the substrate W. The projection system is supported on a reference frame RF. As shown, the apparatus is of a transmissive type (e.g. using a transmissive mask). Alternatively, the apparatus may be of a reflective type (eg employing a programmable mirror array, or employing a reflective mask).

[0042]

[0059] The illuminator IL receives the radiation beam from the radiation source SO. The source and the lithographic apparatus may be separate, for example when the source is an excimer laser. In such cases the source is not considered to form part of the lithographic apparatus and the radiation beam is passed from the source SO to the illuminator IL using a beam delivery system BD, for example comprising suitable directing mirrors and / or beam expanders. In other cases the source may be an integral part of the apparatus, for example when the source is a mercury lamp. The source SO and the illuminator IL, together with the beam delivery system BD if required, may be referred to as a radiation system.

[0043]

[0060] The illuminator IL may vary the intensity distribution of the beam. The illuminator may be arranged to limit the radial extent of the radiation beam such that the intensity distribution is non-zero in an annular region in a pupil plane of the illuminator IL. Additionally or alternatively, the illuminator IL may be operable to limit the distribution of the beam in the pupil plane such that the intensity distribution is non-zero in a number of equally spaced sectors in the pupil plane. The intensity distribution of the radiation beam in the pupil plane of the illuminator IL may be referred to as the illumination mode.

[0044]

[0061] The illuminator IL may comprise an adjuster AD configured to adjust the (angular / spatial) intensity distribution of the beam. Typically, at least the outer and / or inner radial extent (typically referred to as σ-outer and σ-inner, respectively) of the intensity distribution in a pupil plane of the illuminator may be adjusted. The illuminator IL may be operable to vary the angular distribution of the beam. For example, the illuminator may be operable to vary the number and angular extent of sectors in the pupil plane where the intensity distribution is non-zero. By adjusting the intensity distribution of the beam in the pupil plane of the illuminator, various illumination modes may be achieved. For example, by limiting the radial and angular extent of the intensity distribution in the pupil plane of the illuminator IL, the intensity distribution may have a multipole distribution, such as, for example, a dipole, quadrupole or hexapole distribution. A desired illumination mode may be obtained, for example, by inserting an optical component providing that illumination mode into the illuminator IL or by using a spatial light modulator.

[0045]

[0062] The illuminator IL may be operable to change the polarization of the beam and may be operable to adjust the polarization using the adjuster AD. The polarization state of the radiation beam across a pupil plane of the illuminator IL may be referred to as the polarization mode. Using different polarization modes may result in greater contrast in the image formed on the substrate W. The radiation beam may be unpolarized. Alternatively, the illuminator may be arranged to linearly polarize the radiation beam. The polarization direction of the radiation beam may vary across the pupil plane of the illuminator IL. The polarization direction of the radiation may be different in different regions in the pupil plane of the illuminator IL. The polarization state of the radiation may be chosen depending on the illumination mode. In the case of a multipole illumination mode, the polarization of each pole of the radiation beam may be approximately perpendicular to the position vector of that pole in the pupil plane of the illuminator IL. For example, in the case of a dipole illumination mode, the radiation may be linearly polarized in a direction substantially perpendicular to a line that bisects two opposing sectors of the dipole. The radiation beam may be polarized in one of two different orthogonal directions, which may be referred to as the X and Y polarization states. In a quadrupole illumination mode, the radiation in each pole sector may be linearly polarized in a direction substantially perpendicular to a line that bisects the sector. This polarization mode may be referred to as XY polarization. Similarly, in a hexapole illumination mode, the radiation in each pole sector may be linearly polarized in a direction substantially perpendicular to a line that bisects the sector. This polarization mode may be referred to as TE polarization.

[0046]

[0063] The illuminator IL will generally also comprise various other components, such as an integrator IN and a condenser CO. An illumination system may comprise various optical components, such as refractive, reflective, magnetic, electromagnetic, electrostatic or other types of optical components, or any combination thereof, for directing, shaping or controlling radiation.

[0047]

[0064] The illuminator thus provides a conditioned beam of radiation B having a desired uniformity and intensity distribution in its cross-section.

[0048]

[0065] The support structure MT supports the patterning device in a manner that depends on the orientation of the patterning device, the design of the lithographic apparatus, and other conditions, such as for example whether or not the patterning device is held in a vacuum environment. The support structure may use mechanical, vacuum, electrostatic or other clamping techniques to hold the patterning device. The support structure may be for example a frame or a table, which may be fixed or movable as required. The support structure may ensure that the patterning device is at a desired position, for example with respect to the projection system. Any use of the terms "reticle" or "mask" herein may be considered as synonymous with the more general term "patterning device".

[0049]

[0066] The term "patterning device" as used herein should be interpreted broadly to refer to any device that can be used to impart a pattern to a target portion of a substrate. In an embodiment, a patterning device is any device that can be used to impart a radiation beam with a pattern in its cross-section to generate a pattern in the target portion of the substrate. It should be noted that the pattern imparted to the radiation beam may not exactly correspond to the pattern desired in the target portion of the substrate, for example if the pattern includes phase-shifting features or so-called assist features. Generally, the pattern imparted to the radiation beam will correspond to a particular functional layer in a device being created in the target portion of the device, such as an integrated circuit.

[0050]

[0067] A patterning device may be of a transmissive or reflective type. Examples of patterning devices include masks, programmable mirror arrays, and programmable LCD panels. Masks are well known in lithography and include binary, alternating phase-shift, and attenuated phase-shift, as well as various hybrid masks. An example of a programmable mirror array employs a matrix arrangement of small mirrors, each of which can be individually tilted so as to reflect an incoming radiation beam in different directions. The tilting mirrors impart a pattern to the radiation beam which is reflected from the mirror matrix.

[0051]

[0068] The term "projection system" as used herein includes refractive optics, catadioptric, catadioptric, magnetic, electromagnetic and electrostatic optics, or any combination thereof, and should be interpreted broadly to encompass any type of projection system that is suitable with respect to the exposure radiation used or with respect to other factors such as the use of an immersion liquid or the use of a vacuum. Any use of the term "projection lens" herein may be considered as synonymous with the more general term "projection system".

[0052]

[0069] The projection system PS may comprise a number of optical (e.g., lens) elements and may further comprise an adjustment mechanism configured to adjust one or more of the optical elements to correct aberrations (phase changes across the pupil plane across the field). To achieve this, the adjustment mechanism may be operable to manipulate one or more optical (e.g., lens) elements in the projection system PS in one or more different ways. The projection system may have a coordinate system whose optical axis extends in the z-direction. The adjustment mechanism may be operable to displace one or more optical elements, tilt one or more optical elements, and / or deform one or more optical elements in any combination. The displacement of the optical elements may be in any direction (x, y, z, or combinations thereof). The tilt of the optical elements is typically out of plane perpendicular to the optical axis by rotation about an axis in the x and / or y directions, although rotation about the z-axis may be used for non-rotationally symmetric aspheric optical elements. The deformation of the optical element may include a low frequency shape (e.g. astigmatism) and / or a high frequency shape (e.g. free form asphericity). The deformation of the optical element may be performed, for example, by exerting a force on one or more sides of the optical element using one or more actuators and / or by heating one or more selected regions of the optical element using one or more heating elements. In general, it may not be possible to adjust the projection system PS to correct the apodization (change in transmission at the pupil plane). A transmission map of the projection system PS may be used in designing a patterning device (e.g. mask) MA for the lithographic apparatus LA. Computational lithography techniques may be used to design the patterning device MA to at least partially correct the apodization.

[0053]

[0070] The lithographic apparatus may be of a type having two (dual stage) or more tables (e.g. two or more substrate tables WTa, WTb, two or more patterning device tables, a substrate table WTa and a table WTb below the projection system that does not contain the substrate, e.g. dedicated to facilitating measurement and / or cleaning, etc.). In such a "multi-stage" machine, the additional tables may be used in parallel, or preparatory steps may be performed on one or more tables whilst the other one or more tables are used for exposure. For example, alignment measurements may be made using alignment sensors AS and / or level (height, tilt, etc.) measurements using level sensors LS.

[0054]

[0071] The lithographic apparatus may also be of a type in which at least a portion of the substrate is covered by a liquid having a relatively high refractive index, e.g. water, filling a space between the projection system and the substrate. An immersion liquid may also be applied to other spaces in the lithographic apparatus, for example between the patterning device and the projection system. Immersion techniques are well known in the art for increasing the numerical aperture of projection systems. The term "immersion" as used herein does not imply that a structure such as the substrate has to be immersed in liquid, but simply that a liquid is located between the projection system and the substrate during exposure.

[0055]

[0072] In operation of a lithographic apparatus, a radiation beam is conditioned and provided by an illumination system IL. The radiation beam B is incident on a patterning device (e.g. mask) MA, which is held on a support structure (e.g. mask table) MT, and is patterned by the patterning device. After traversing the patterning device MA, the radiation beam B passes through a projection system PS, which focuses the beam onto a target portion C of a substrate W. Using a second positioner PW and a position sensor IF (e.g. an interferometric device, a linear encoder, a 2D encoder or a capacitive sensor), the substrate table WT can be accurately moved, for example to position different target portions C in the path of the radiation beam B. Similarly, the first positioner PM and another position sensor (not explicitly shown in FIG. 1 ) can be used to accurately position the patterning device MA with respect to the path of the radiation beam B, for example after mechanical retrieval from a mask library or during a scan. In general, movement of the support structure MT may be realized using a long-stroke module (coarse positioning) and a short-stroke module (fine positioning), which form part of the first positioner PM. Similarly, movement of the substrate table WT may be realized using a long-stroke module and a short-stroke module, which form part of the second positioner PW. In the case of a stepper (as opposed to a scanner) the support structure MT may be connected to a short-stroke actuator only, or may be fixed. The patterning device MA and the substrate W may be aligned using the patterning device alignment marks M1, M2 and substrate alignment marks P1, P2. Although the substrate alignment marks as illustrated occupy dedicated target portions, they may be located in spaces between the target portions (these are known as scribe-lane alignment marks). Similarly, in situations in which more than one die is provided on the patterning device MA, the patterning device alignment marks may be located between the dies.

[0056]

[0073] The depicted apparatus may be used in at least one of the following modes: In step mode, the support structure MT and the substrate table WT are kept substantially stationary while a pattern imparted to the radiation beam is projected onto the target portion C in one go (i.e. a single static exposure), and the substrate table WT is moved in the X and / or Y direction so that a different target portion C can be exposed. In step mode, a maximum size of the exposure field limits the size of the target portion C imaged in a single static exposure. In scan mode, the support structure MT and the substrate table WT are scanned synchronously while a pattern imparted to the radiation beam is projected onto the target portion C (i.e. a single dynamic exposure). The velocity and direction of the substrate table WT relative to the support structure MT may be determined by the (de-)magnification and image reversal characteristics of the projection system PS. In scan mode, the maximum size of the exposure field limits the width (in non-scan direction) of the target portion in a single dynamic exposure, whereas the length of the scanning motion determines the height (in scan direction) of the target portion. In another mode, the support structure MT is kept substantially stationary holding the programmable patterning device and the substrate table WT is moved or scanned while a pattern imparted to the radiation beam is projected onto the target portion C. In this mode, a pulsed radiation source is generally used and the programmable patterning device is updated as required after each movement of the substrate table WT, or between successive radiation pulses during a scan. This mode of operation can readily be applied to maskless lithography employing a programmable patterning device such as a programmable mirror array of the type mentioned above.

[0057]

[0074] Combinations and / or variations on the above described modes of use or entirely different modes of use may also be employed.

[0058]

[0075] Substrates referred to herein may be processed, before or after exposure, for example in a track (a tool that typically applies a layer of resist to a substrate and develops the exposed resist) or a metrology tool or an inspection tool. Where applicable, the disclosure herein may apply to these and other substrate processing tools. Furthermore, a substrate may be processed more than once, for example to produce a multi-layer IC, and thus the term substrate as used herein may also refer to a substrate that already includes multiple processed layers.

[0059]

[0076] The terms "radiation" and "beam" as used herein with respect to lithography encompass all types of electromagnetic radiation, including ultraviolet (UV) or deep ultraviolet (DUV) radiation (e.g., having a wavelength of 365 nm, 248 nm, 193 nm, 157 nm or 126 nm) and extreme ultraviolet (EUV) radiation (e.g., having a wavelength in the range of 5 to 20 nm), as well as particle beams such as ion beams and electron beams.

[0060]

[0077] Various patterns on or provided by a patterning device may have different process windows, i.e., a space of process variables within which the patterns are to be produced. Examples of pattern specifications related to potential systematic defects include checking necking, line pullback, thinning, CD, edge placement, overlap, resist top loss, resist undercut and / or bridging. The process window of a pattern on a patterning device or an area thereof may be obtained by merging (e.g., overlapping) the process windows of each of the individual patterns. The boundary of the process window of a group of patterns includes the boundaries of the process windows of several individual patterns. In other words, these individual patterns limit the process window of the group of patterns.

[0061]

[0078] As shown in FIG. 2, the lithographic apparatus LA may form part of a lithographic cell LC, sometimes called a lithocell or cluster, which also includes apparatus for performing pre-exposure and post-exposure processes on the substrate. Conventionally, these include one or more spin coaters SC for depositing one or more resist layers, one or more developers for developing the exposed resist, one or more chill plates CH and / or one or more bake plates BK. A substrate handler or robot RO picks up one or more substrates from input / output ports I / O1, I / O2, moves them between the different process apparatus and delivers them to a loading bay LB of the lithographic apparatus. These apparatuses are often collectively referred to as a track, and are under the control of a track control unit TCU, which is itself controlled by a supervisory control system SCS, which also controls the lithographic apparatus via a lithography control unit LACU. The various apparatuses can thus be operated to maximize throughput and processing efficiency.

[0062]

[0079] To ensure that a substrate exposed by a lithographic apparatus is accurately and consistently exposed and / or to monitor a part of a patterning process (e.g., a device manufacturing process) that includes at least one pattern transfer step (e.g., a photolithography step), it is desirable to inspect a substrate or other object to measure or determine one or more properties, such as alignment, overlay (e.g., between structures of overlapping layers, or between structures in the same layer, e.g., provided separately in that layer by a double patterning process), linewidth, critical dimension (CD), focus offset, material properties, etc. Thus, a manufacturing facility in which the lithocell LC is located typically also includes a metrology system that measures some or all of the substrates W (FIG. 1) processed in the lithocell, or other objects in the lithocell. The metrology system may be part of the lithocell LC, or may be part of the lithographic apparatus LA (e.g., alignment sensor AS (FIG. 1)).

[0063]

[0080] The one or more parameters measured may include, for example, alignment, overlay between successive layers formed in or on the patterned substrate, critical dimension (CD) (e.g., critical line width) of features formed in or on the patterned substrate, focus or focus error of an optical lithography step, dose or dose error of an optical lithography step, optical aberrations of an optical lithography step, etc. The measurements are often made on dedicated metrology targets provided on the substrate. The measurements may be made after resist development and before etching, after etching, after deposition, and / or at other times.

[0064]

[0081] There are various techniques, including the use of scanning electron microscopes, image-based metrology tools, and / or various specialized tools, for making measurements of structures formed in a patterning process. As discussed above, a fast and non-invasive form of specialized metrology tool is one that directs a beam of radiation onto a target on the substrate surface and measures properties of the scattered (diffracted / reflected) beam. By evaluating one or more properties of the radiation scattered by the substrate, one or more properties of the substrate can be determined. Traditionally, this is sometimes referred to as diffraction-based metrology. One application of this diffraction-based metrology is the measurement of alignment. For example, alignment can be measured by comparing portions of a diffraction spectrum (e.g., comparing different diffraction orders in the diffraction spectrum of a periodic grating).

[0065]

[0082] Thus, in a device manufacturing process (e.g., a patterning process or a lithography process), a substrate or other object may be subjected to various types of measurements during or after the process. The measurements may determine whether a particular substrate is defective, may establish adjustments of the process and the equipment used in the process (e.g., aligning two layers on a substrate or aligning a patterning device to a substrate), may measure the performance of the process and the equipment, or may be for other purposes. Examples of measurements include optical imaging (e.g., optical microscopes), non-imaging optical measurements (e.g., diffraction-based measurements such as ASML's YieldStar metrology tools, ASML's SMASH metrology systems), mechanical measurements (e.g., profiling with a stylus, atomic force microscope (AFM)), and / or non-optical imaging (e.g., scanning electron microscope (SEM)). The SMASH (SMart Alignment Sensor Hybrid) system, described in U.S. Pat. No. 6,961,116, the entirety of which is incorporated herein by reference, employs a self-referencing interferometer that produces two overlapping, relatively rotated images of an alignment marker, detects the intensity in the pupil plane where the Fourier transforms of the images are interfered, and extracts position information from the phase difference between the diffraction orders of the two images, which appears as an intensity change in the interfered orders.

[0066]

[0083] The metrology results may be provided directly or indirectly to a supervisory control system SCS. If errors are detected, adjustments may be made to the exposure of subsequent substrates (especially if inspection can be done soon enough and quickly enough to allow further exposure of one or more other substrates in the batch) and / or to subsequent exposures of the exposed substrate. Also, already exposed substrates may be stripped and reworked to improve yield, or may be discarded, thereby avoiding further processing of substrates known to be defective. If only some target portions of a substrate are defective, further exposures may be made only to those target portions that meet specifications. Other manufacturing process adjustments are also possible.

[0067]

[0084] A metrology system may be used to determine one or more properties of a substrate structure, in particular how one or more properties vary for different substrate structures or how different layers of the same substrate structure vary from layer to layer. The metrology system may be integrated into the lithographic apparatus LA or lithocell LC, or may be a stand-alone device.

[0068]

[0085] To enable metrology, one or more targets are often specially provided on the substrate. The targets may include, for example, alignment marks and / or other targets. Typically, the targets are specially designed and may include periodic structures. For example, the target on the substrate may include one or more 1D periodic structures (e.g., geometric features such as gratings) that are printed such that, after development, the periodic structural features are formed with solid resist lines. As another example, the target may include one or more 2D periodic structures (e.g., gratings) that are printed such that, after development, the periodic structures are formed with solid resist pillars or vias in the resist. The bars, pillars, or vias may alternatively be etched into the substrate (e.g., one or more layers on the substrate).

[0069]

[0086] FIG. 3 shows an exemplary inspection system 10 that may be used to detect alignment and / or perform other metrology operations. The inspection system 10 comprises a source projector 2 that projects or otherwise irradiates radiation onto a substrate W (e.g., which may typically comprise an alignment mark). The redirected radiation is passed to a sensor such as a spectrometer detector 4 and / or other sensors that measure the spectrum (intensity as a function of wavelength) of the specularly reflected and / or diffracted radiation, for example as shown in the graph on the left of FIG. 4. The sensor may generate an alignment signal that conveys alignment data characteristic of the reflected radiation. From this data, the structure or profile giving rise to the detected spectrum may be reconstructed by one or more processors PU, a generalized example of which is shown in FIG. 4, or by other operations. It should be noted that these are generalized examples. Often, illumination of targets such as alignment marks is orthogonal to the target and / or mark and not at an angle as shown in these figures.

[0070]

[0087] Similar to the lithographic apparatus LA of FIG. 1, one or more substrate tables (not shown in FIG. 4) may be provided to hold the substrate W during measurement operations. The one or more substrate tables may be similar or identical in form to the substrate table WT (WTa or WTb or both) of FIG. 1. In an example where the inspection system 10 is integrated with a lithographic apparatus, it may be the same substrate table. Coarse and fine positioners may be provided and configured to accurately position the substrate with respect to the measurement optical system. For example, various sensors and actuators are provided to acquire the position of the target portion of the structure (e.g., alignment mark) of interest and to bring the target portion into position under the objective lens. Typically, many measurements will be made on the target portion of the structure at different locations on the substrate W. The substrate support can be moved in the X and Y directions to acquire the various targets and in the Z direction to obtain the desired location of the target portion relative to the focus of the optical system. For example, when in fact the optical system remains substantially stationary (typically in X and Y directions, but possibly also in Z direction) but the substrate moves, it is convenient to think about and describe operation as if the objective lens were brought to different locations relative to the substrate. Provided the relative positions of the substrate and optical system are correct, in principle it does not matter which of them, or both, or some combination of the optical system are moving (e.g. in Z and / or tilt directions), while the rest of the optical system remains stationary and the substrate is moving (e.g. in X and Y directions, but optionally also in Z and / or tilt directions).

[0071]

[0088] In a typical alignment measurement, the target (portion) 30 on the substrate W may be a 1D grating that is printed such that after development, the bars are formed of solid resist lines (which may be covered by a deposition layer, for example) and / or other material. Alternatively, the target 30 may be a 2D grating that is printed such that after development, the grating is formed of solid resist pillars and / or other features in the resist.

[0072]

[0089] The bars, pillars, vias, and / or other features may be etched into or on the substrate (e.g., in one or more layers on the substrate), deposited on the substrate, covered with a deposition layer, and / or have other properties. The target (portion) 30 (e.g., the bars, pillars, vias, etc.) is sensitive to processing variations in the patterning process (e.g., optical aberrations, focus changes, dose changes, etc., in the lithographic projection apparatus, e.g., in the projection system), such that process variations manifest themselves as variations in the target 30. Measurement data from the target 30 may therefore be used to determine adjustments to one or more of the manufacturing processes and / or used as a basis for making actual adjustments.

[0073]

[0090] For example, the measurement data from target 30 may indicate an alignment for a layer of a semiconductor device. The measurement data from target 30 may be used (e.g., by one or more processors) to determine one or more semiconductor device manufacturing process parameters based on the alignment, and to determine adjustments of the semiconductor device manufacturing equipment based on the determined one or more semiconductor device manufacturing process parameters. In some embodiments, this may include, for example, stage position adjustments, or may include determining adjustments to mask design, metrology target (e.g., alignment mark) design, semiconductor device design, intensity of radiation, angle of incidence of radiation, wavelength of radiation, pupil size and / or shape, resist material, and / or other process parameters.

[0074]

[0091] Angle resolved scatterometry is useful in measuring the asymmetry of product features and / or resist patterns. A particular application of asymmetry measurement is for alignment measurements. The basic concept of asymmetry measurement using the system 10 of FIG. 3 is described, for example, in U.S. Patent Application Publication No. 2006-066855, which is incorporated herein in its entirety. Briefly, in alignment measurements, the positions of the diffraction orders in the diffraction spectrum of a target are determined by the periodicity of the target (e.g., alignment marks). The asymmetry of the diffraction spectrum indicates the asymmetry of the individual features that make up the target. For example, any region that spans a significant portion of the exposure field to the entire exposure field is a useful region for more accurate intra-field alignment fitting. Also, the same feature present in any field located along a straight line can be captured in successive scans across most or the entire wafer size, providing more accurate inter-field alignment fitting.

[0075]

[0092] FIG. 5 shows a plan view of a typical target (e.g., alignment mark) 30 and the extent of the emitted illumination spot S in the system of FIG. 4. Typically, to obtain a diffraction spectrum without interference from surrounding structures, in one embodiment, the target 30 is a periodic structure (e.g., grating) that is larger than the width (e.g., diameter) of the illumination spot S. The width of the spot S may be smaller than the width and length of the target. The target is in other words "underfilled" by the illumination, and the diffraction signal essentially does not include any signal from product features outside the target itself, etc. The illuminator may be configured to provide a uniform intensity illumination across, for example, the back focal plane of the objective lens. Alternatively, the illumination may be limited in the on-axis or off-axis direction, for example, by including an aperture in the illumination path.

[0076]

[0093] FIG. 6 illustrates a method 600 for generating a metrology signal. In some embodiments, generating the metrology signal is performed as part of a semiconductor device manufacturing process. In some embodiments, one or more operations of the method 600 may be performed in or by the system 10 illustrated in FIGS. 3 and 4, a computer system (e.g., as illustrated in FIG. 15 and described below), and / or in or by other systems. In some embodiments, the method 600 includes irradiating a feature in a patterned substrate with radiation (operation 602), detecting radiation reflected from the feature (operation 604), generating a metrology signal based on the detected radiation (operation 606), and / or other operations. The method 600 is described below in the context of alignment, but this is not intended to be limiting. The method 600 may be generally applied to a number of different processes.

[0077]

[0094] The operations of method 600 presented below are intended to be illustrative. In some embodiments, method 600 may be accomplished by one or more additional operations not described and / or without one or more of the operations discussed. For example, in some embodiments, method 600 may include additional operations including determining adjustments to a semiconductor device manufacturing process. Additionally, the order in which the operations of method 600 are shown in FIG. 6 and described below is not intended to be limiting.

[0078]

[0095] In some embodiments, one or more portions of method 600 may be implemented in and / or controlled by one or more processing devices (e.g., digital processors, analog processors, digital circuits designed to process information, analog circuits designed to process information, state machines, and / or other mechanisms for electronically processing information). The one or more processing devices may include one or more devices that perform some or all of the operations of method 600 in response to instructions electronically stored on an electronic storage medium. The one or more processing devices may include one or more devices configured through hardware, firmware, and / or software to be specifically designed (e.g., see the discussion below regarding FIG. 15 ) to perform one or more of the operations of method 600.

[0079]

[0096] Operation 602 includes irradiating a feature in a patterned substrate with radiation. The feature includes a target portion of the patterned substrate (e.g., as described above in connection with FIGS. 3-5), but is distinct from a dedicated alignment mark (e.g., a diffraction grating). The feature is distinct from a dedicated alignment structure or other structure near the feature and within the illumination spot. The feature includes one or more structures in the patterned substrate that can provide a diffraction signal. In some embodiments, the feature can be any structure in the pattern design layout that can generate a wide angle diffraction signal.

[0080]

[0097] The features may be included, for example, in a layer of a substrate of a semiconductor device structure. In some embodiments, the features include geometric features such as 1D or 2D features, and / or other geometric features. As some non-limiting examples, the features may include lines, edges, a series of fine pitch lines and / or edges, and / or other features. In some embodiments, the fine pitch has a pitch dimension of, for example, less than 1 micrometer. In some embodiments, the features (e.g., lines, edges, series, etc.) have a length that spans the area to be measured (e.g., an area that is larger than a typical target such as the width / length of a die, but may be as long as the full diameter of a wafer).

[0081]

[0098] The radiation may have a target wavelength and / or wavelength range, a target intensity, and / or other characteristics. The target wavelength and / or wavelength range, target intensity, etc. may be input and / or selected by a user, determined by the system based on previous alignment measurements, and / or otherwise determined. In some embodiments, the radiation includes light and / or other radiation. In some embodiments, the light includes visible light, infrared light, near infrared light, and / or other light. In some embodiments, the radiation may be any radiation suitable for interferometry.

[0082]

[0099] The radiation may be generated by a radiation source (e.g., projector 2 shown in Figures 3 and 4 and described above). In some embodiments, the radiation may be directed by the radiation source onto the feature, a sub-portion of the feature (e.g., less than the entire feature), multiple features, and / or otherwise onto the substrate. In some embodiments, the radiation may be directed by the radiation source onto the feature in a time-varying manner. For example, the radiation may be rastered across the feature such that different portions of the feature are illuminated at different times. As another example, the characteristics of the radiation (e.g., wavelength, intensity, etc.) may vary. This may create a time-varying data envelope, or window, for analysis. The data envelope may facilitate analysis of individual sub-portions of the feature, comparison of one portion of the feature to another portion and / or other features, and / or other analysis.

[0083]

[0100] Operation 604 includes detecting reflected radiation from the features. Detecting the reflected radiation includes detecting one or more phase and / or amplitude (intensity) shifts of the reflected radiation from one or more geometric features. The one or more phase and / or amplitude shifts correspond to one or more dimensions of the features. For example, the phase and / or amplitude of the reflected radiation from one side of the feature is different relative to the phase and / or amplitude of the reflected radiation from another side of the feature.

[0084]

[0101] Detecting one or more phase and / or amplitude (intensity) shifts of the reflected radiation from the feature may include measuring local phase shifts (e.g., local phase delta) and / or amplitude variations corresponding to different portions of the feature. For example, reflected radiation from a particular area of ​​the feature may include a sinusoidal waveform having a particular phase and / or amplitude. Reflected radiation from a different area of ​​the feature may also include a sinusoidal waveform, but with a different phase and / or amplitude. Detecting the reflected radiation may also include measuring the phase and / or amplitude differences of the reflected radiation of different diffraction orders. Detecting one or more local phase and / or amplitude shifts may be performed, for example, using the Hilbert transform and / or other techniques. Interferometry and / or other operations may be used to measure the phase and / or amplitude differences of the reflected radiation of different diffraction orders.

[0085]

[0102] The illuminating (operation 602) and detecting (operation 604) include scanning, which is configured to run faster and generate more information than typical systems for generating metrology signals because the scanning is performed on features that are already part of the pattern design layout (e.g., compared to alignment marks that are added as an extra part of the pattern), the scanning continuously samples over a large area of ​​the field or wafer rather than a series of individual alignment marks, the scanned features are configured to span the interior of a device die without causing processing and packaging issues, and / or for other reasons.

[0086]

[0103] As mentioned above, the scan is continuous. Continuous scanning has the advantage that it eliminates the need for preparation steps required for individual scans, which can be of the same order of magnitude as the scan time itself. Continuous scanning involves a substantially uninterrupted rastering of the radiation beam along or across the feature. This allows for a substantially continuous sampling of deformations and / or other dimensional characteristics over a relatively large area of ​​the substrate (semiconductor wafer) at a steady constant speed. This contrasts with, for example, scanning a series of individual alignment marks, where slow scanning or steering is required to keep the signal below the cut-off limit of the detector, and where most of the time is spent accelerating and decelerating the wafer stage as opposed to capturing the optical signal. This makes the current process faster than common methods. The scan is performed faster because it is performed on existing features, rather than a series of individual alignment marks, and continuously samples deformations over a large area of ​​the substrate (semiconductor wafer).

[0087]

[0104] The scan may have a radiation beam trajectory across the feature. The radiation beam trajectory across the feature may include a path that the radiation beam follows as it is rastered across the feature. For example, the radiation beam may be controlled to follow a particular path relative to the feature. The radiation beam trajectory may be provided to a measurement system, such as, for example, an ASML SMASH and / or Orion system. The radiation beam trajectory may be configured such that the scan is performed perpendicular to the feature, along one side of the feature, such that a spot size of the radiation covers one side of a line and / or edge feature, along both sides of the feature, such that a spot size of the radiation covers both sides of the feature simultaneously, and / or otherwise.

[0088]

[0105] As a non-limiting example, Figure 7 shows a first possible version of a scan, where the radiation beam trajectory 700 is perpendicular to a feature 702. In this example, the feature 702 is a scribe line indicated with reference to a die 704 (e.g., and / or corresponding reticle / mask) in a field 706 on a substrate or wafer 708. Figure 7 shows how a radiation spot 710 crosses the scribe line (feature) 702 along the trajectory 700. Figure 7 shows a perpendicular isolated line scan, which can, for example, capture the scribe line directly.

[0089]

[0106] As a second non-limiting example, FIG. 8 shows a second possible version of a scan in which a radiation beam trajectory 800 follows one edge 801 of a feature 802. Again, the feature 802 is a scribe line indicated with reference to a die 804 (e.g., and / or corresponding reticle / mask) of a field 806 on a substrate or wafer 808. FIG. 8 shows a radiation spot 810 following one edge of the scribe line (feature) 802 along the trajectory 800. FIG. 8 shows a parallel isolated line scan. The spot size of the spot 810 can capture one edge of the scribe line and can be scanned at any speed, for example, allowing capture of longer scale variations across the wafer 808. In this example, measurement information (e.g., feature dimensions, feature position, and / or other alignment related information) may be generated by interfering the diffraction pattern generated by the edge 801 with itself and / or other actions.

[0090]

[0107] As a third non-limiting example, FIG. 9 shows a third possible version of the scan in which the radiation beam trajectory 900 follows both edges 901, 903 of a feature 902. Again, the feature 902 is a scribe line indicated with reference to a die 904 (e.g., and / or corresponding reticle / mask) in a field 906 on a substrate or wafer 908. FIG. 9 shows how the radiation spot 910 follows the trajectory 900 and surrounds both edges of the scribe line (feature) 902. FIG. 9 shows a parallel isolated line scan between the two scribe lines. The spot size of the spot 910 is large enough to capture both edges of the scribe line, enhancing lateral scan offset sensitivity. In this example, measurement information (e.g., feature dimensions, feature location, and / or other alignment related information) may be generated by interfering a diffraction pattern generated by one edge 901 with a diffraction pattern generated by the other edge 903, and / or other actions.

[0091]

[0108] In some embodiments, the scan is performed at a predefined scan speed for a predefined sampling rate. The predefined scan speed and / or the predefined sampling rate are determined based on the size and / or other information of the features. In some embodiments, the predefined scan speed and / or the predefined sampling rate are adjustable based on the size and / or other characteristics of the features. Conversely, in some embodiments, the size of the features that may be scanned is determined based on a ratio of the predefined scan speed to the predefined sampling rate.

[0092]

[0109] For example, the relationship between scan speed, sampling rate, and feature size may be defined by an equation the same as or similar to equation 1050 shown in FIG. min is the minimum scannable feature size, v is the scanning speed, f samplingis the sampling frequency, and DF is the anti-aliasing filter / detection frequency metrology system. Various examples of units (e.g., μm, mm / s, kHz) are shown in equation 1050, but are not intended to be limiting. As shown in FIG. 10, the present system and method can be used to measure features as small as desired by scanning the features at a predefined scan speed, given the minimum sampling rate of the metrology system. In other words, by changing the scan speed, the present system and method may be used to measure relatively small features that are part of the design layout, instead of larger specially designed alignment marks that were added to the design layout for metrology purposes.

[0093]

[0110] Advantageously, using one of the techniques described in Figures 7-9 in combination with equation 1050 shown in Figure 10, no additional space on the substrate is required for dedicated alignment marks. These techniques can be extended to printing control lines and / or dual-use CMP dams. Throughput can be increased compared to traditional metrology processes. These techniques are flexible with respect to spot size and sensor type. These techniques can be used even when the scribe line is shrinking (e.g., double edge interference as shown in Figure 9), can be used to probe various scan lengths (e.g., multiple dedicated alignment marks), can be used for 2D scanning (e.g., perpendicular to the scribe line direction) to improve noise and fitting functions, and / or have other advantages.

[0094]

[0111] Returning to FIG. 6 , operation 606 includes generating a metrology signal based on the detected reflected radiation from the feature. The metrology signal includes measurement information about the feature. For example, the metrology signal may be an alignment signal including alignment measurement information, an overlay signal including overlay measurement information, and / or other metrology signals. In some embodiments, operation 606 includes determining an alignment inspection position of the feature based on the metrology signal. The measurement information (e.g., the alignment inspection position of the feature) may be determined using principles of interferometry and / or other principles.

[0095]

[0112] The metrology signal includes an electronic signal representative of and / or otherwise corresponding to the radiation reflected from the feature. The metrology signal may be indicative of, for example, an alignment value of the feature, and / or other information. Producing the metrology signal includes detecting the reflected radiation and converting the detected reflected radiation into an electronic signal. In some embodiments, generating the metrology signal includes detecting different portions of the reflected radiation from different areas and / or different geometric shapes of the feature, and combining the different portions of the reflected radiation to form the metrology signal. This detecting and converting may be performed by components similar to and / or the same as the detector 4, detector 18, and / or processor PU, and / or other components shown in Figures 3 and 4.

[0096]

[0113] In some embodiments, generating the metrology signal may include directly measuring the dimensions of the features. For example, direct dimension measurements of the features may be made using a scatterometer and / or other system. In some embodiments, the direct dimension measurements may be used in combination with and / or in place of the local phase and / or amplitude shifts described herein to determine alignment of the features. For example, output dimension measurements from a scatterometer system may be provided to a processor PU (FIG. 3) and / or other system components, which may generate a metrology signal based at least in part on the output dimension measurements from the scatterometer system.

[0097]

[0114] In some embodiments, the metrology signal is calibrated based on a scan of the feature isolated from other surrounding structures. In some embodiments, the metrology signal is calibrated based on a vertical or parallel line scan. Once calibrated, the metrology signal can be configured in a number of different ways. For example, in some embodiments, the metrology signal includes a signal from parallel flank scans. The signal from the flank scan includes diffraction oriented perpendicularly from the scan direction. The signal from the parallel flank scan includes a difference between a signal from a first scan of the feature and a signal from a second parallel scan of the feature. In some embodiments, the metrology signal includes a signal from two parallel flank scans for two corresponding features from two different regions of the substrate. The signal from the two parallel flank scans includes a difference between a first signal from a first parallel flank scan from a first region and a second signal from a second parallel flank scan from a second region. The given signal from the given parallel flank scan comprises a difference between a signal from a first scan of the feature and a signal from a second parallel scan of the feature, and the different regions comprise different dies on one substrate or the same die across different substrates. Some of the possible configurations of the calibration and metrology signals are further described below in conjunction with Figures 11-14. It should be noted that the dimensions, speeds, frequencies, configurations, etc. of the metrology signals described as part of Figures 11-14 are examples only and are not intended to be limiting. Other possible dimensions, speeds, frequencies, configurations, etc. of the metrology signals are contemplated.

[0098]

[0115] FIG. 11 shows one possible example of metrology signal calibration. In FIG. 11, a simulation of a destructive interference vertical scan (e.g., a vertical isolated line scan) for a 0.4 μm wide line 1102 (e.g., one possible example of a feature described herein) is shown in view 1101 (e.g., a spot 1104 crosses the line 1102 horizontally). View 1103 shows the calibration signal 1106 at the detector and how the signal 1106 changes with position 1107 (relative to the line 1102 as the spot 1104 crosses the line 1102). A filter may be applied to the signal 1106 based on the detector, but since (in this example) this is a slow scan (e.g., 11 mm / s), the filter does not modify the signal 1106. In this example, the detector simulation uses resampling to an available sampling rate of 20-320 kHz, including two filters, a second order Bessel low pass filter with a cutoff frequency of 120 kHz, and an anti-aliased 8th order finite impulse response that cuts off at half the sampling rate. In this simulation, 320 kHz sampling was selected. The central portion 1109 of the signal 1106 (e.g., the portion where the signal 1106 is changing rapidly and consistently such that the shape of the signal 1106 appears as a parabola) may form a calibration reference for later scans.

[0099]

[0116] View 1105 of FIG. 11 shows a derived calibration curve 1110 (at a given calibration offset 1111) of paired flank scans (described below) based on the simulations shown in views 1101 and 1103. As noted above, the portion of signal 1106 that is useful for calibration is portion 1109 (e.g., the interior about + / - 170 nm in this example) where signal 1106 changes abruptly and smoothly. Curve 1110 is derived by sampling portion 1109 and plotting the sampled points. (For example, a series of sub-alignment resolution lines (<<1.6 nm pitch) may look similar.) This sampling and plotting may effectively broaden portion 1109. The curve is based on a vertical scan of a version of the target feature, but isolated from the surroundings. Portion 1109 is useful because the position offset and interference intensity signal are linear and stable. Curve 1110 is obtained by taking derivatives or finite differences over a range of parallel flank scan offsets. This is a direct relationship between the position offset of the alignment feature from the spot center and the measured interference intensity level.

[0100]

[0117] For scanning such lines (e.g., features) in a parallel direction (e.g., along or parallel to a given feature), the basis for this type of scanning is described in European Patent EP2131243B1, which is incorporated by reference in its entirety, where this type of scanning was referred to as a "flank scan". In some embodiments, for this type of scanning, two parallel scans may be more useful than one parallel scan. The first parallel scan may follow the first scan path (along the feature) and the second parallel scan may follow a second scan path that is offset a certain amount in a certain direction from the first scan path (e.g., along the same feature as well, while being slightly offset relative to the first scan path such that the second scan is performed along the same feature but not in the same location as the first scan). By taking the difference of the two signals from the two parallel scans, the capture range is extended, allowing for clear scanning on either the falling or rising side of the internal signal (e.g., portion 1109 above), and may facilitate further flexibility in the presence of background that would be cancelled out. The two parallel scans comprise "twinned flank scans." The advantage of these flank scans and the high scan speed (e.g., possible because the scan follows continuous lines and / or other features as described above) is that it makes it easier to match the signal frequency to the bandwidth of the detector, which is not possible with normal alignment marks. A normal alignment mark needs to be scanned at a scan speed of about 8-22 mm / s to allow a small enough signal frequency (about 6-28 kHz) so that the sensor system can adequately acquire data. Higher signal frequencies start to suffer from a drop in the amplitude of the sensor's transfer function. However, nominally straight lines (and / or other features described herein) give rise to flat signals and do not lose signal even at faster scan speeds. As a specific example, the scan speed of the wafer (substrate) stage during exposure is typically 700-900 mm / s, and this range is appropriate for this type of scan.As described herein, the present systems and methods facilitate metrology of features with or without surrounding structures (eg, a line alone and / or a line that includes several other nearby features).

[0101]

[0118] With the present system and method, the metrology throughput is nearly neutral, for example, compared to that for sampling conventional alignment marks and fitting them to a third-order intrafield model. Fitting 20 terms would require at least 4 vertical and 4 horizontal scans over the field (using multiple, 4 or more resolution elements per scan). Depending on the design layout, whether scanning the same field or adjacent fields, for example, each move between scans would take the DUV stage about 30-80 ms. Each scan would take about 40 ms. This totals about 500-900 ms. A paired flank scan of a full field (e.g., as described herein) would take about 1000-1800 ms. Compare this to scanning 10 BF (or CB) marks distributed over the field, which would take about 500 ms to scan if scanned consecutively. There may be further optimizations with possible routing.

[0102]

[0119] A difficulty in measuring features in a patterned substrate is that the spot size of the radiation used for inspection typically covers other uncontrolled structures, such as other alignment marks, overlay targets, and / or other product features. This creates noise and other unwanted portions of the measured signal that can overwhelm desired portions of the signal (e.g., portions of the signal that correspond to desired metrology targets). The present systems and methods overcome this and other difficulties.

[0103]

[0120] For example, FIG. 12 shows a frank scan 1200 for an exemplary feature that includes a distorted single line 1202 structure. In the scan 1200, a radiation spot 1204 travels along or substantially parallel to the line 1202. This structure may be a portion of a semiconductor product and / or any other portion of a patterned substrate (e.g., a wafer). Plot 1203 shows a metrology signal 1206 at the detector and how the signal 1206 varies with position 1207 (relative to the line 1202 as the spot 1204 travels along the line 1202). Note that the signal 1206 is clean and smooth, with no variations due to messy structures at or near the line 1202 of the patterned substrate. In this and the following examples, an arbitrary fixed detector gain is assumed.

[0104]

[0121] Figure 13 shows a frank scan 1300 for a distorted line 1302 structure (e.g., similar and / or identical to the line 1102 structure shown in Figure 11 and the line 1202 structure shown in Figure 12), but including other surrounding pattern features ("clutter") 1303, 1305, 1307, and 1309. In the scan 1300, a radiation spot 1304 travels along or substantially parallel to the line 1302. Figure 13 also shows a metrology signal 1312 at the detector and a plot 1310 showing how the signal 1312 varies with position 1314 (relative to the line 1302 and the clutter 1303-1309 as the spot 1304 travels along the line 1302). Note that signal 1312 is noisy, with fluctuations 1320, 1322, 1324, and 1326 caused by clutter 1303-1309 at or near the line 1302 of the patterned substrate. If this data could be fitted accurately enough, it would provide a means to directly fit, for example, absolute field distortion. In this example, signal 1312 is sampled at 20 kHz and conditioned with a low-pass anti-aliasing filter to try to suppress high frequency noise from the background. This helps to better define signal 1312 for metrology purposes, but (in this example) is not sufficient on its own. The dotted line 1321 shows a filtered version of the signal. Line 1321 shows how low-pass filtering can help to suppress the effects of clutter without losing resolution of the main signal. Low-pass filtering may be combined with other operations such as parallel flank scanning or multi-field or multi-substrate relative methods to achieve increased accuracy.

[0105]

[0122] Plot 1350 in FIG. 3, for example, shows signal 1352 from a repeat of the same scan 1300, but now with a y offset of -20 nm (e.g., paired (parallel) flank scan). Plot 1350 shows a raw version 1360 and a filtered version 1362 of signal 1352. Plot 1350 shows that this small offset sees a very similar background as the first scan, but the main signal is significantly different, so that the paired (parallel) flank scan can be used to remove unwanted noise and / or other variations. This removal may be performed, for example, by subtracting one signal from the other to determine the difference between the signals, and / or by other operations, as described herein. Note that 1310 and 1350 are very similar in terms of their clutter signals. In the wide field of view of FIG. 13, it is difficult to see the underlying signal difference, but the difference in FIG. 14 at 1406 (described below) is a practical way to visualize the difference.

[0106]

[0123] FIG. 14 shows data from the application of the paired (parallel) flank scans described above. FIG. 14 shows a plot 1400 comparing a calibration signal 1402 with a signal 1404 from a scan without clutter and a signal 1406 from a scan with background clutter. Plot 1400 shows scan offset 1420 on the x-axis and non-scan offset 1422 on the y-axis. Signal 1404 is very accurate (e.g., sits almost on top of signal 1402), but in this example, clutter causes an average offset of 7.5 nm in signal 1406. This is typically too large for intra-field correction in semiconductor manufacturing processes, but the offset will vary depending on the actual surrounding structure and regularity across the field (which may increase or decrease the offset). Additional filtering and / or optimized filtering may also be effective.

[0107]

[0124] In some embodiments, multiple parallel flank scans may be used. Most of the noise introduced by surrounding structures (clutter) may be cancelled (e.g., removed) using signals from paired (parallel) flank scans (e.g., by subtracting one signal of the pair from the other), as shown in Figure 13. However, for any surrounding structure, the metrology signal from paired (parallel) flank scans may still be too noisy for general use.

[0108]

[0125] Plot 1450 in FIG. 14 shows the difference in measured non-scan offsets for two paired (parallel) flank scan signals 1452 with the same surrounding structure (clutter) but different intra-field warping functions with respect to a calibration signal 1454. Plot 1450 shows the difference in scan offset 1460 on the x-axis and the measured non-scan offset 1462 on the y-axis. Using paired flank scans and applying a calibration signal from the central region of a vertical isolated line scan (e.g., as described above), the recovered offset (e.g., the difference in measured non-scan offsets of the two paired (parallel) flank scan signals 1452) between two distorted lines (e.g., from different wafers or regions of a wafer) compared to the calibration signal 1454 is sub-nanometer, which is accurate enough for intra-field wafer alignment in semiconductor manufacturing processes. In this way, relative correction between different fields or substrates can be achieved with the required accuracy. Specifically, the average error in position on this reasonable resolution element is 17 pm, which is a relative accuracy sufficient for all modern semiconductor manufacturing processes. Furthermore, a 1 mm resolution element allows for intra-field models of up to 25-32nd order, much higher than the 3rd order commonly used today.The various warping functions describe common design layout features (e.g., slightly distorted lines as in the example considered above) with realistic wafer-to-wafer variations.

[0109]

[0126] Briefly, in some embodiments, the metrology signal includes signals from parallel flank scans. The signals from the flank scans include diffractions oriented perpendicularly from the scan direction. The signals from the parallel flank scans include a difference between a signal from a first scan of the feature and a signal from a second parallel scan of the feature. To summarize the information presented in FIG. 14, in some embodiments, the metrology signal includes signals from two parallel flank scans for two corresponding features from two different regions of a substrate (e.g., a wafer), or two substrates, etc. The signals from the two parallel flank scans include a difference between a first signal from a first parallel flank scan of a first region and a second signal from a second parallel flank scan of a second region. A given signal from a given parallel flank scan includes a difference between a signal from a first scan of the feature and a signal from a second parallel scan of the feature, the different regions including different dies on one substrate, or the same die between different substrates. Using paired (parallel) flank scans and applying a calibration signal (e.g., as described above), the difference in the measured unscanned offset of two paired (parallel) flank scan signals (e.g., 1452) between features (e.g., two distorted lines from different wafers or areas of a wafer) compared to the calibration signal 1454 is on the order of nanometers or less, which is accurate enough for intra-field wafer alignment in semiconductor manufacturing processes.

[0110]

[0127] Returning to FIG. 6 , in some embodiments, operation 606 includes determining an adjustment to a semiconductor device manufacturing process. In some embodiments, operation 606 includes determining one or more semiconductor device manufacturing process parameters. The one or more semiconductor device manufacturing process parameters may be determined based on one or more detected phase and / or amplitude variations, alignment values ​​indicated by metrology signals, dimensions determined by a scatterometer system and / or other similar systems, and / or other information. The one or more parameters may include a parameter of the radiation (radiation used to determine the alignment), an alignment inspection location within the feature, an alignment inspection location on a layer of the semiconductor device structure, a trajectory of a radiation beam across the feature, and / or other parameters. In some embodiments, the process parameters may be broadly interpreted to include a stage position, a mask design, a metrology target design, a semiconductor device design, an intensity of radiation (e.g., for exposing a resist), an angle of incidence of radiation (e.g., for exposing a resist), a wavelength of radiation (e.g., for exposing a resist), a pupil size and / or shape, a resist material, and / or other parameters.

[0111]

[0128] Parameters of the radiation used to determine alignment may include, for example, wavelength, intensity, angle of incidence, and / or parameters of the radiation. These parameters may be adjusted to better measure features having a particular shape, to increase the intensity of the reflected radiation, to increase and / or enhance (e.g., maximize) the phase and / or amplitude shift (if any) of the reflected radiation from one area of ​​the feature to the next, and / or for other purposes. This may enable and / or enhance the detection of more subtle deviations, facilitate detection of phase and / or amplitude shifts, and / or provide other advantages.

[0112]

[0129] In some embodiments, operation 606 includes determining process adjustments based on the one or more determined semiconductor device manufacturing process parameters, adjusting semiconductor device manufacturing equipment based on the determined adjustments, and / or other operations. For example, if the determined alignment is not within a process tolerance, one or more manufacturing processes may cause misalignment, and the process parameters of one or more manufacturing processes may have drifted and / or otherwise changed so that the process no longer produces acceptable devices (e.g., alignment measurements may exceed a threshold for acceptability). One or more new or adjusted process parameters may be determined based on the alignment determination. The new or adjusted process parameters may be configured to cause the manufacturing process to produce acceptable devices again. For example, the new or adjusted process parameters may adjust a previously unacceptable alignment (or misalignment) back to within an acceptable range. The new or adjusted process parameters may be compared to existing parameters for a given process. If there is a difference, the difference may be used, for example, to determine an adjustment to an apparatus used to manufacture the device (e.g., parameter "x" needs to be increased / decreased / changed to match the new or adjusted version of parameter "x" determined as part of act 606). In some embodiments, act 606 may include electronically adjusting the apparatus (e.g., based on the determined process parameters). Electronically adjusting the apparatus may include, for example, sending an electronic signal to the apparatus that effects a change in the apparatus, and / or other communication. The electronic adjustment may include, for example, changing a setting on the apparatus, and / or other adjustment.

[0113]

[0130] FIG. 15 is a diagram of an exemplary computer system CS that may be used for one or more of the operations described herein. The computer system CS comprises a bus BS or other communication mechanism for communicating information, and a processor PRO (or multiple processors) for processing information coupled to the bus BS. The computer system CS also comprises a main memory MM, such as a random access memory (RAM) or other dynamic storage device, for storing information and instructions executed by the processor PRO coupled to the bus BS. The main memory MM may also be used to store temporary variables or other intermediate information during execution of instructions by the processor PRO. The computer system CS further comprises a read-only memory (ROM) ROM or other static storage device for storing static information and instructions for the processor PRO coupled to the bus BS. A storage device SD, such as a magnetic or optical disk, for storing information and instructions is provided and coupled to the bus BS.

[0114]

[0131] The computer system CS may be coupled via a bus BS to a display DS, such as a cathode ray tube (CRT) or flat panel or touch panel display, for displaying information to a computer user. Input devices ID, including alphanumeric and other keys, are coupled to the bus BS for communicating information and command selections to the processor PRO. Another type of user input device is a cursor control CC, such as a mouse, trackball, or cursor direction keys, for communicating directional information and command selections to the processor PRO and for controlling cursor movement on the display DS. This input device typically has two degrees of freedom in two axes, a first axis (e.g., x) and a second axis (e.g., y), allowing the device to be located in a plane. Touch panel (screen) displays may also be used as input devices.

[0115]

[0132] In some embodiments, parts of one or more methods described herein may be performed by the computer system CS in response to the processor PRO executing one or more sequences of one or more instructions contained in the main memory MM. Such instructions may be read into the main memory MM from another computer-readable medium, such as a storage device SD. Execution of the sequences of instructions contained in the main memory MM causes the processor PRO to perform the process steps (operations) described herein. One or more processors of a multiprocessing device may also be used to execute the sequences of instructions contained in the main memory MM. In some embodiments, hard-wired circuitry may be used in place of or in combination with software instructions. Thus, the description herein is not limited to any specific combination of hardware circuitry and software.

[0116]

[0133] The term "computer-readable medium" or "machine-readable medium" as used herein refers to any medium that participates in providing instructions to a processor PRO for execution. Such media may take many forms, including, but not limited to, non-volatile media, volatile media, and transmission media. Non-volatile media include, for example, optical or magnetic disks, such as a storage device SD. Volatile media include dynamic memory, such as a main memory MM. Transmission media include coaxial cables, copper wires, and optical fibers (including the wires that comprise the bus BS). Transmission media may also take the form of acoustic or light waves, such as those generated during radio frequency (RF) and infrared (IR) data communications. The computer-readable medium may be a non-transitory computer-readable medium, such as a floppy disk, a flexible disk, a hard disk, a magnetic tape, any other magnetic medium, a CD-ROM, a DVD, any other optical medium, a punch card, a paper tape, any other physical medium with a pattern of holes, a RAM, a PROM, and an EPROM, a FLASH-EPROM, any other memory chip or cartridge. The non-transitory computer-readable medium may record instructions. The instructions, when executed by a computer, can perform any of the operations described herein. The transitory computer-readable medium may include, for example, a carrier wave or other propagating electromagnetic signal.

[0117]

[0134] Various forms of computer readable media may be involved in carrying one or more sequences of one or more instructions to the processor PRO for execution. For example, the instructions may initially reside on a magnetic disk of a remote computer. The remote computer may load the instructions into its dynamic memory and send the instructions over a telephone line using a modem. A modem local to the computer system CS may receive the data on the telephone line and use an infrared transmitter to convert the data to an infrared signal. An infrared detector coupled to the bus BS may receive the data carried in the infrared signal and place the data on the bus BS. The bus BS carries the data to the main memory MM, from which the processor PRO retrieves and executes the instructions. The instructions received by the main memory MM may optionally be stored in a storage device SD before or after execution by the processor PRO.

[0118]

[0135] The computer system CS may also comprise a communication interface CI coupled to a bus BS. The communication interface CI provides a two-way data communication coupling to a network link NDL, which is connected to a local network LAN. For example, the communication interface CI may be an Integrated Services Digital Network (ISDN) card or a modem providing a data communication connection to a corresponding telephone line type. As another example, the communication interface CI may be a Local Area Network (LAN) card providing a data communication connection to a compatible LAN. A wireless link may also be implemented. In such implementations, the communication interface CI transmits and receives electrical, electromagnetic or optical signals that carry digital data streams representing various types of information.

[0119]

[0136] The network link NDL typically provides data communication through one or more networks to other data devices. For example, the network link NDL may provide a connection to a host computer HC through a local network LAN. This may include data communication services provided through a World Wide Packet Data Communication Network (now commonly referred to as the "Internet" INT). The local network LAN (Internet) may use electrical, electromagnetic or optical signals that carry digital data streams. The signals through the various networks as well as the signals on the network data link NDL and through the communication interface CI that carry digital data to the computer system CS are exemplary forms of carrier waves transporting information.

[0120]

[0137] The computer system CS can send messages and receive data including program code through the network, the network data link NDL, and the communication interface CI. In the Internet example, the host computer HC may send a request code of an application program through the Internet INT, the network data link NDL, the local network LAN, and the communication interface CI. One such downloaded application may provide, for example, all or part of the methods described herein. The received code may be executed by the processor PRO when received and / or stored in the storage device SD or other non-volatile storage for later execution. The computer system CS may thus obtain the application code in the form of a carrier wave.

[0121]

[0138] Figure 16 shows a schematic diagram of an exemplary lithographic projection apparatus similar and / or the same as the apparatus shown in Figure 1 that may be used in conjunction with the techniques described herein. The apparatus 1000 comprises an illumination system IL for conditioning a radiation beam B. In this particular case, the illumination system also comprises a radiation source SO, a first object table (e.g., patterning device table) MT provided with a patterning device holder for holding a patterning device MA (e.g., a reticle) and connected to a first positioner PM (working in conjunction with a first position sensor PS1) for accurately positioning the patterning device, a second object table (substrate table) WT provided with a substrate holder for holding a substrate W (e.g., a resist-coated silicon wafer) and connected to a second positioner PW (working in conjunction with a second position sensor PS2) for accurately positioning the substrate, and a projection system ("lens") PS (e.g., a refractive, reflective or catadioptric optical system) for imaging an illuminated portion of the patterning device MA onto a target portion C of the substrate W (e.g., comprising one or more dies).

[0122]

[0139] As depicted herein, the apparatus is of a transmissive type (i.e. has a transmissive patterning device). In general, however, the apparatus may be of a reflective type (e.g. has a reflective patterning device). The apparatus may employ other types of patterning device than a conventional mask; examples include a programmable mirror array or an LCD matrix.

[0123]

[0140] A radiation source SO (e.g. a mercury lamp or excimer laser, LPP (Laser Produced Plasma) EUV source) produces a beam of radiation. This beam is fed into an illumination system (illuminator) IL, either directly or after having traversed conditioning means, such as a beam expander Ex. The illuminator IL may comprise conditioning means for setting the outer and / or inner extent (commonly referred to as σ-outer and σ-inner, respectively) of the intensity distribution of the beam. The illuminator IL will generally also comprise various other components, such as an integrator and a condenser. In this way, the beam B impinging on the patterning device MA has a desired uniformity and intensity distribution in its cross-section.

[0124]

[0141] It should be noted with regard to Figure 16 that the source SO can be within the housing of the lithographic projection apparatus (as is the case when the source SO is, for example, a mercury lamp), but it may also be remote from the lithographic projection apparatus, and the radiation beam it generates can be directed into the apparatus (for example by means of suitable directing mirrors), this latter scenario being typical when the source SO is an excimer laser (for example based on KrF, ArF or F2 lasing).

[0125]

[0142] The beam B is then intercepted by the patterning device MA, which is held on a patterning device table MT. After traversing the patterning device MA, the beam B passes through a lens, which focuses the beam B onto a target portion C of the substrate W. Using the second positioning means (and interferometry means), the substrate table WT can be accurately moved to, for example, position different target portions C in the path of the beam B. Similarly, the first positioning means may be used to accurately position the patterning device MA with respect to the path of the beam B, for example after mechanical retrieval of the patterning device MA from a patterning device library or during a scan. Typically, movement of the object tables MT, WT will be realized with the aid of not explicitly stated long-stroke modules (coarse positioning) and short-stroke modules (fine positioning). However, in the case of a stepper (as opposed to a step-and-scan tool) the patterning device table MT may simply be connected to a short-stroke actuator, or may be fixed.

[0126]

[0143] The depicted tool (similar or the same as that shown in FIG. 1 ) can be used in two different modes. In step mode, the patterning device table MT is kept essentially stationary and the entire patterning device image is projected onto the target portion C in one movement (i.e. in a single "flash"). The substrate table WT is then shifted in the x and / or y direction so that a different target portion C can be irradiated with the beam B. In scan mode, essentially the same scenario applies, but a given target portion C is not exposed in a single "flash". Instead, the patterning device table MT is movable in a given direction (the so-called "scan direction", e.g. the y direction) with a speed v, such that the projection beam B scans the patterning device image while the substrate table WT is simultaneously moved in the same or opposite direction with a speed V=Mv, in which M is the magnification of the lens PL (typically M=¼ or ⅕). In this way, a relatively large target portion C can be exposed, without having to compromise on resolution.

[0127]

[0144] FIG. 17 shows the apparatus 1000 with the source collector module SO, the illumination system IL and the projection system PS in more detail. The source collector module SO is constructed and arranged such that a vacuum environment can be maintained within the closed structure 220 of the source collector module SO. The EUV radiation emitting plasma 210 may be formed by a discharge produced plasma source. The EUV radiation may be generated by a gas or vapor, for example Xe gas, Li vapor or Sn vapor, in which a high temperature plasma 210 is created to emit radiation in the EUV range of the electromagnetic spectrum. The plasma 210 is for example created by an electric discharge that produces an at least partially ionized plasma. For example, a partial pressure of 10 Pa of Xe, Li, Sn vapor or any other suitable gas or vapor may be required for efficient generation of radiation. In an embodiment, a plasma of excited tin (Sn) is provided to generate the EUV radiation.

[0128]

[0145] Radiation emitted by the plasma 210 passes from the source chamber 211 into the collector chamber 212 via an optional gas barrier or contamination trap 230 (sometimes called a contamination barrier or foil trap) located in or behind the opening of the source chamber 211. The contamination trap 230 may comprise a channel structure. The contamination trap 230 may also comprise a gas barrier or a combination of a gas barrier and a channel structure. The contamination trap 230 as further illustrated herein comprises at least a channel structure.

[0129]

[0146] The source chamber 211 may comprise a radiation collector CO, 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 traversing the collector CO may be reflected off a grating spectral filter 240 and focused to a virtual source point IF along an optical axis indicated by line "O". The virtual source point IF is commonly referred to as an intermediate focus, and the source collector module is configured such that the intermediate focus IF is located at or near the opening 221 of the enclosure structure 220. The virtual source point IF is an image of the radiation emitting plasma 210.

[0130]

[0147] The radiation subsequently traverses an illumination system IL, which may comprise a faceted field mirror device 22 and a facetted pupil mirror device 24 configured to provide a desired angular distribution of the radiation beam 21 at the patterning device MA, and a desired uniformity of the radiation intensity at the patterning device MA. Upon reflection of the radiation beam 21 off the patterning device MA, held by a support structure MT, a patterned beam 26 is formed, which is imaged by the projection system PS via reflective elements 28, 330 onto a substrate W held by a substrate table WT.

[0131]

[0148] Generally, more elements than shown may be present in the illumination optics unit IL and projection system PS. A grating spectral filter 240 may optionally be present depending on the type of lithographic apparatus. Further, there may be more mirrors than shown, for example 1-6 additional reflective elements may be present in the projection system PS than shown in Figure 17.

[0132]

[0149] 17 is depicted as a nested collector with grazing incidence reflectors 253, 254 and 255 as just one example of a collector (or collector mirror). The grazing incidence reflectors 253, 254 and 255 are arranged axially symmetrically about the optical axis O, and this type of collector optic CO is sometimes used in combination with a discharge produced plasma source, often referred to as a DPP source.

[0133]

[0150] Alternatively, the source collector module SO may be part of an LPP radiation system as shown in Fig. 18. A laser LA is configured to impart laser energy to a fuel such as xenon (Xe), tin (Sn) or lithium (Li) to generate a highly ionized plasma 210 with an electron temperature of tens of eV. Energetic radiation generated during de-excitation and recombination of these ions is emitted from the plasma and collected by a near-normal incidence collector system CO and focused into an opening 221 in a confinement structure 220.

[0134]

[0151] Various embodiments of the present systems and methods are disclosed in the following list of numbered clauses: 1. A system for generating a metrology signal, the system comprising: a radiation source configured to irradiate radiation onto a feature of a patterned substrate distinct from a dedicated alignment structure, a sensor configured to detect reflected radiation from the feature, and one or more processors configured to generate a metrology signal comprising measurement information about the feature based on the detected reflected radiation from the feature. 2. The system of clause 1, wherein the features include one or more structures in a patterned substrate capable of providing a diffraction signal. 3. The system of clause 1 or 2, wherein the feature is distinct from the dedicated alignment structure and other structures near the feature and within the illumination spot. 4. The system of any one of clauses 1 to 3, wherein the illumination and detection include scanning, and the scanning is continuous. 5. A system of any one of clauses 1 to 4, wherein the feature is a structure capable of generating wide angle diffraction and the scan is performed perpendicular to the feature, along one side of the feature when the spot size of the radiation is configured to cover one side of the feature, or along both sides of the feature when the spot size of the radiation is configured to cover both sides of the feature simultaneously. 6. The system of any one of clauses 1 to 5, wherein the feature comprises a line, an edge, or a series of fine pitch lines and / or edges, and the feature has a length that spans the area to be measured. 7. The system of any one of clauses 1 to 6, wherein the fine pitch has a pitch dimension of less than 1 micrometer. 8. The system of any one of clauses 1 to 7, wherein the illumination and detection include scanning, and the scanning is configured to run faster and generate more information than typical systems for generating metrology signals because the scanning is performed on the features to continuously sample deformation over a large area of ​​a field or wafer rather than a series of individual alignment marks, and because the features are configured to span the interior of a device die without causing processing and packaging issues. 9. The system of any one of clauses 1 to 8, wherein the illumination and detection include scanning, and the scanning is configured to be performed faster and generate more information than typical systems for generating metrology signals because the scanning is performed on features in the patterned substrate instead of on dedicated alignment structures. 10. The system of any one of clauses 1 to 9, wherein the illuminating and detecting includes scanning, and the metrology signal is calibrated based on a scan of the feature isolated from other surrounding structures. 11. The system of any one of clauses 1 to 10, wherein the illumination and detection include scanning, and the metrology signal is calibrated based on a vertical or parallel line scan. 12. The system of any one of clauses 1 to 11, wherein the metrology signal comprises a signal from parallel flank scans, the signal from the flank scans comprises diffraction oriented perpendicular to the scan direction, and the signal from the parallel flank scans comprises a difference between a signal from a first scan of the feature and a signal from a second parallel scan of the feature. 13. The system of any one of clauses 1 to 12, wherein the metrology signal comprises signals from two parallel flank scans for two corresponding features in two different regions, the signals from the two parallel flank scans comprise a difference between a first signal from a first parallel flank scan in a first region and a second signal from a second parallel flank scan in a second region, and the given signal from a given parallel flank scan comprises a difference between a signal from the first scan of the feature and a signal from the second parallel scan of the feature, and the different regions comprise different dies on a substrate or the same die across different substrates. 14. The system of any one of clauses 1 to 13, wherein the illumination and detection include scanning, and the scanning is performed at a predefined scan speed for a predefined sampling rate, and the predefined scan speed and / or the predefined sampling rate are determined based on the size of the feature. 15. The system of any one of clauses 1 to 14, wherein the predetermined scanning speed and / or the predetermined sampling rate is adjustable based on the size of the feature. 16. The system of any one of clauses 1 to 15, wherein the size of features that can be scanned is determined based on a ratio of a predetermined scanning speed to a given sampling rate. 17. A system according to any one of clauses 1 to 16, wherein the features include lines and / or edges, the dedicated alignment structure includes a diffraction grating, and the line and / or edge features form part of the design layout separate from the diffraction grating. 18. The system of any one of clauses 1 to 17, wherein the metrology signal is an alignment signal or an overlay signal. 19. The system of any one of clauses 1 to 18, wherein the one or more processors are further configured to determine alignment inspection positions of the features based on the metrology signals. 20. The system of any one of clauses 1 to 19, wherein the features are included in a layer of a substrate within a semiconductor device structure, and the one or more processors are further configured to adjust a semiconductor device manufacturing process based on the metrology signal. 21. A method of generating a metrology signal, the method comprising: irradiating a feature in a patterned substrate, distinct from a dedicated alignment structure, with radiation; detecting reflected radiation from the feature; and generating a metrology signal comprising measurement information about the feature based on the detected reflected radiation from the feature. 22. The method of clause 21, wherein the features include one or more structures in a patterned substrate capable of providing a diffraction signal. 23. The method of clause 21 or 22, wherein the feature is distinct from the dedicated alignment structure and other structures near the feature and within the illumination spot. 24. The method of any one of clauses 21 to 23, wherein the irradiating and detecting include scanning, and the scanning is sequential. 25. A method according to any one of clauses 21 to 24, wherein the feature is a structure capable of producing wide angle diffraction and the scan is performed perpendicular to the feature, along one side of the feature if the spot size of the radiation is arranged to cover one side of the feature, or along both sides of the feature if the spot size of the radiation is arranged to cover both sides of the feature simultaneously. 26. The method of any one of clauses 21 to 25, wherein the feature comprises a line, an edge, or a series of fine pitch lines and / or edges, and the feature has a length that spans the area to be measured. 27. The method of any one of clauses 21 to 26, wherein the fine pitch has a pitch dimension of less than 1 micrometer. 28. The method of any one of clauses 21 to 27, wherein the illuminating and detecting includes scanning, and the scanning is configured to be performed faster and generate more information than typical systems for generating metrology signals because the scanning is performed on the features to continuously sample deformation over a large area of ​​the field or wafer rather than a series of individual alignment marks, and because the features are configured to span the interior of a device die without causing processing and packaging issues. 29. The method of any one of clauses 21 to 28, wherein the illuminating and detecting includes scanning, and the scanning is configured to be performed faster and generate more information than typical systems for generating metrology signals because the scanning is performed on features in the patterned substrate instead of on dedicated alignment structures. 30. The method of any one of clauses 21 to 29, wherein illuminating and detecting includes scanning, and the metrology signal is calibrated based on a scan of the feature isolated from other surrounding structures. 31. The method of any one of clauses 21 to 30, wherein the illuminating and detecting includes scanning, and the metrology signal is calibrated based on a vertical or parallel line scan. 32. The method of any one of clauses 21 to 31, wherein the metrology signal comprises a signal from parallel flank scans, the signal from the flank scans comprises diffraction oriented perpendicular to the scan direction, and the signal from the parallel flank scans comprises a difference between a signal from a first scan of the feature and a signal from a second parallel scan of the feature. 33. The method of any one of clauses 21 to 32, wherein the metrology signal comprises signals from two parallel flank scans for two corresponding features in two different regions, the signals from the two parallel flank scans comprise a difference between a first signal from a first parallel flank scan in a first region and a second signal from a second parallel flank scan in a second region, and the given signal from a given parallel flank scan comprises a difference between a signal from the first scan of the feature and a signal from the second parallel scan of the feature, and the different regions comprise different dies on a substrate or the same die across different substrates. 34. The method of any one of clauses 21 to 33, wherein the illuminating and detecting includes scanning, and the scanning is performed at a predetermined scan speed for a predetermined sampling rate, and the predetermined scan speed and / or the predetermined sampling rate are determined based on the size of the feature. 35. The method of any one of clauses 21 to 34, wherein the predetermined scanning speed and / or the predetermined sampling rate is adjustable based on the size of the feature. 36. The method of any one of clauses 21 to 35, wherein the size of features that can be scanned is determined based on a ratio of a predetermined scanning speed to a predetermined sampling rate. 37. A method according to any one of clauses 21 to 36, wherein the features comprise lines and / or edges, the dedicated alignment structure comprises a diffraction grating, and the line and / or edge features form part of the design layout separate from the diffraction grating. 38. The method of any one of clauses 21 to 37, wherein the metrology signal is an alignment signal or an overlay signal. 39. The method of any one of clauses 21 to 38, further comprising determining an alignment inspection position of the feature based on the metrology signal. 40. The method of any one of clauses 21 to 39, wherein the feature is included in a layer of a substrate within a semiconductor device structure, and the method further comprises adjusting a semiconductor device manufacturing process based on the metrology signal. 41. A non-transitory computer readable medium having instructions that, when executed by a computer, cause operations including irradiating a feature in a patterned substrate that is distinct from a dedicated alignment structure with radiation, detecting reflected radiation from the feature, and generating a metrology signal that includes measurement information about the feature based on the detected reflected radiation from the feature. 42. The medium of clause 41, wherein the features include one or more structures in a patterned substrate capable of providing a diffraction signal. 43. A medium according to clause 41 or 42, in which the feature is distinct from a dedicated alignment structure and from other structures adjacent to the feature and within the illumination spot. 44. The medium of any one of clauses 41 to 43, wherein the irradiating and detecting include scanning, and the scanning is continuous. 45. A medium according to any one of clauses 41 to 44, wherein the feature is a structure capable of producing wide angle diffraction and the scan is performed perpendicular to the feature, along one side of the feature if the spot size of the radiation is arranged to cover one side of the feature, or along both sides of the feature if the spot size of the radiation is arranged to cover both sides of the feature simultaneously. 46. ​​The medium of any one of clauses 41 to 45, wherein the feature comprises a line, an edge, or a series of fine pitch lines and / or edges, and the feature has a length that spans the area to be measured. 47. The medium of any one of clauses 41 to 46, wherein the fine pitch has a pitch dimension of less than 1 micrometer. 48. The medium of any one of clauses 41 to 47, wherein the illumination and detection include scanning, and the scanning is configured to be performed faster and generate more information than typical systems for generating metrology signals because the scanning is performed on the features to continuously sample deformation over a large area of ​​the field or wafer rather than a series of individual alignment marks, and because the features are configured to span the interior of a device die without causing processing and packaging issues. 49. The medium of any one of clauses 41 to 48, wherein the illumination and detection include scanning, and the scanning is configured to be performed faster and generate more information than typical systems for generating metrology signals because the scanning is performed on features in the patterned substrate instead of on dedicated alignment structures. 50. The medium of any one of clauses 41 to 49, wherein the illuminating and detecting includes scanning, and the metrology signal is calibrated based on a scan of the feature isolated from other surrounding structures. 51. The medium of any one of clauses 41 to 50, wherein the illuminating and detecting includes scanning, and the metrology signal is calibrated based on a vertical or parallel line scan. 52. The medium of any one of clauses 41 to 51, wherein the metrology signal comprises a signal from parallel flank scans, the signal from the flank scans comprises diffraction oriented perpendicular to the scan direction, and the signal from the parallel flank scans comprises a difference between a signal from a first scan of the feature and a signal from a second parallel scan of the feature. 53. The medium of any one of clauses 41 to 52, wherein the metrology signal comprises signals from two parallel flank scans for two corresponding features in two different regions, the signals from the two parallel flank scans comprise a difference between a first signal from a first parallel flank scan in a first region and a second signal from a second parallel flank scan in a second region, and the given signal from a given parallel flank scan comprises a difference between a signal from the first scan of the feature and a signal from the second parallel scan of the feature, and the different regions comprise different dies on a substrate or the same die across different substrates. 54. The medium of any one of clauses 41 to 53, wherein the illumination and detection include scanning, and the scanning is performed at a predetermined scanning speed for a predetermined sampling rate, and the predetermined scanning speed and / or the predetermined sampling rate are determined based on the size of the feature. 55. The medium of any one of clauses 41 to 54, wherein the predetermined scanning speed and / or the predetermined sampling rate is adjustable based on the size of the feature. 56. The medium of any one of clauses 41 to 55, wherein the size of a feature that can be scanned is determined based on a predetermined ratio of a scanning speed to a given sampling rate. 57. The medium of any one of clauses 41 to 56, wherein the features include lines and / or edges, the dedicated alignment structure includes a diffraction grating, and the line and / or edge features form part of the design layout separate from the diffraction grating. 58. The medium of any one of clauses 41 to 57, wherein the metrology signal is an alignment signal or an overlay signal. 59. The medium of any one of clauses 41-58, wherein the operations further include determining alignment inspection positions of the features based on the metrology signals. 60. The medium of any one of clauses 41-59, wherein the features are included in a layer of a substrate within a semiconductor device structure, and the method further includes adjusting a semiconductor device manufacturing process based on the metrology signal. 61. A method of generating alignment signals for alignment of features in a layer of a substrate as part of a semiconductor manufacturing process, the method being configured to run faster and generate more information than typical methods of generating alignment signals because the method is performed on existing structures in a patterned semiconductor wafer instead of dedicated alignment structures, the method comprising continuously scanning line and / or edge features of the patterned semiconductor wafer, the line and / or edge features being distinct from dedicated alignment marks typically included on patterned semiconductor wafers, the scanning comprising continuously irradiating the line and / or edge features with radiation and continuously detecting reflected radiation from the line and / or edge features, the scanning being performed perpendicular to the line and / or edge features, along one side of the line and / or edge features, or along both sides of the line and / or edge features, and generating an alignment signal configured to be used to adjust the semiconductor manufacturing process based on the detected reflected radiation from the line and / or edge features. 62. The method of clause 61, wherein the alignment signal is calibrated based on a scan of a feature isolated from surrounding structures. 63. The method of clause 61 or 62, wherein the alignment signal comprises a signal from parallel flank scans, the signal from the flank scans comprises diffraction oriented perpendicular to the scan direction, and the signal from the parallel flank scans comprises a difference between a signal from a first scan of the line and / or edge feature and a signal from a second parallel scan of the line and / or edge feature. 64. The method of any one of clauses 61 to 63, wherein the alignment signal comprises signals from two parallel flank scans for two corresponding line and / or edge features of two different regions, the signal from the two parallel flank scans comprising a difference between a first signal from a first parallel flank scan of a first region and a second signal from a second parallel flank scan of a second region, and the given signal from a given parallel flank scan comprises a difference between a signal from a first scan of the line and / or edge feature and a signal from a second parallel scan of the line and / or edge feature, and the different regions comprise different dies on one substrate or the same die across different substrates. 65. A method according to any one of clauses 61 to 64, wherein the scanning is performed at a predefined scanning speed for a predefined sampling rate, the predefined scanning speed and / or the predefined sampling rate being determined based on the size of the line and / or edge features.

[0135]

[0152] The concepts disclosed herein may be associated with any general imaging system for imaging sub-wavelength features, and may be particularly useful with new imaging techniques capable of producing ever-shorter wavelengths. New techniques already in use include EUV (Extreme Ultraviolet), DUV lithography capable of producing 193 nm wavelengths with ArF lasers, and even 157 nm wavelengths with Fluorine lasers. EUV lithography can also produce wavelengths in the range of 20-5 nm by using synchrotrons or by bombarding materials (either solids or plasmas) with high energy electrons to produce photons in this range.

[0136]

[0153] Although the concepts disclosed herein may be used for imaging onto substrates such as silicon wafers, it is to be understood that the disclosed concepts may be used with any type of lithographic imaging system, for example, those used for imaging onto substrates other than silicon wafers. Additionally, combinations and subcombinations of the disclosed elements may constitute separate embodiments.

[0137]

[0154] The above description is intended to be illustrative and not limiting. Thus, it will be apparent to one skilled in the art that modifications can be made as described without departing from the scope of the claims set forth below.

Claims

1. 1. A system for generating a metrology signal, the system comprising: a radiation source configured to apply radiation to features of the patterned substrate distinct from the dedicated alignment structure; a sensor configured to detect reflected radiation from the feature; one or more processors configured to generate the metrology signal, the metrology signal including measurement information about the feature, based on detected reflected radiation from the feature; A system equipped with.

2. The system of claim 1 , wherein the features include one or more structures in the patterned substrate capable of providing a diffraction signal.

3. The system of claim 1 or 2, wherein the feature is distinct from the dedicated alignment structure and other structures near the feature and within the illumination spot.

4. The system of claim 1 , wherein the illuminating and the detecting include scanning, and the scanning is continuous.

5. the features being structures capable of producing wide angle diffraction, and the scanning perpendicular to the feature, along one side of the feature when the spot size of the radiation is configured to cover said side of the feature; or along both sides of the feature when the spot size of the radiation is configured to simultaneously cover both sides of the feature. The system of claim 4 .

6. 6. The system of claim 1 , wherein the feature comprises a line, an edge, or a series of fine pitch lines and / or edges, the feature having a length spanning an area to be measured.

7. The system of claim 6 , wherein the fine pitch has a pitch dimension of less than 1 micrometer.

8. 8. The system of claim 1 , wherein the illuminating and detecting includes scanning, the scanning being configured to run faster and generate more information than typical systems for generating metrology signals because the scanning is performed on the feature to continuously sample deformations over a large area of ​​a field or wafer rather than a series of individual alignment marks, and because the feature is configured to span an interior of a device die without causing processing and packaging issues.

9. 9. The system of claim 1 , wherein the irradiating and detecting includes scanning, the scanning being configured to be performed faster and generate more information than typical systems for generating metrology signals because the scanning is performed on the features of the patterned substrate instead of the dedicated alignment structure.

10. The system of claim 1 , wherein the illuminating and the detecting include scanning, and the metrology signal is calibrated based on a scan of the feature isolated from other surrounding structures.

11. The system of claim 1 , wherein the illuminating and detecting include scanning, and the metrology signal is calibrated based on a vertical or parallel line scan.

12. 12. The system of claim 1 , wherein the metrology signal comprises a signal from parallel flank scans, the signal from the flank scans comprising diffraction oriented perpendicular to the scan direction, and the signal from the parallel flank scans comprising a difference between a signal from a first scan of the feature and a signal from a second parallel scan of the feature.

13. 13. The system of claim 1, wherein the metrology signal comprises signals from two parallel flank scans for two corresponding features in two different regions, the signals from the two parallel flank scans comprising a difference between a first signal from a first parallel flank scan in a first region and a second signal from a second parallel flank scan in a second region, and a given signal from a given parallel flank scan comprises a difference between a signal from a first scan of the feature and a signal from a second parallel scan of the feature, and the different regions comprise different dies on one substrate or the same die across different substrates.

14. 14. The system of claim 1, wherein the illuminating and detecting includes scanning, the scanning being performed at a predetermined scan speed for a predetermined sampling rate, the predetermined scan speed and / or the predetermined sampling rate being determined based on a size of the feature.

15. The system of claim 14 , wherein the predefined scan speed and / or the predetermined sampling rate are adjustable based on the size of the feature.

16. 16. The system of claim 14 or 15, wherein a size of a feature that can be scanned is determined based on a ratio of the predetermined scanning speed to the predetermined sampling rate.

17. 17. The system of claim 1 , wherein the features include lines and / or edges, the dedicated alignment structure includes a diffraction grating, and the line and / or edge features form part of a design layout separate from the diffraction grating.

18. The system of claim 1 , wherein the metrology signal is an alignment signal or an overlay signal.

19. The system of claim 1 , wherein the one or more processors are further configured to determine an alignment inspection position of the feature based on the metrology signal.

20. 20. The system of claim 1, wherein the feature is included in a layer of the substrate within a semiconductor device structure, and the one or more processors are further configured to adjust a semiconductor device manufacturing process based on the metrology signal.

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