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WO2025031758A1 - Système d'alignement et appareil lithographique - Google Patents

Système d'alignement et appareil lithographique Download PDF

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Publication number
WO2025031758A1
WO2025031758A1 PCT/EP2024/070435 EP2024070435W WO2025031758A1 WO 2025031758 A1 WO2025031758 A1 WO 2025031758A1 EP 2024070435 W EP2024070435 W EP 2024070435W WO 2025031758 A1 WO2025031758 A1 WO 2025031758A1
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WIPO (PCT)
Prior art keywords
alignment
diffraction
beams
aspects
target
Prior art date
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Pending
Application number
PCT/EP2024/070435
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English (en)
Inventor
Krishanu SHOME
Kirill Urievich SOBOLEV
Aniruddha Ramakrishna SONDE
Mahesh Upendra AJGAONKAR
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ASML Netherlands BV
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ASML Netherlands BV
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Publication of WO2025031758A1 publication Critical patent/WO2025031758A1/fr
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Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F9/00—Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically
    • G03F9/70—Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically for microlithography
    • G03F9/7003—Alignment type or strategy, e.g. leveling, global alignment
    • G03F9/7019—Calibration
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F9/00—Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically
    • G03F9/70—Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically for microlithography
    • G03F9/7049—Technique, e.g. interferometric
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03F—PHOTOMECHANICAL PRODUCTION OF TEXTURED OR PATTERNED SURFACES, e.g. FOR PRINTING, FOR PROCESSING OF SEMICONDUCTOR DEVICES; MATERIALS THEREFOR; ORIGINALS THEREFOR; APPARATUS SPECIALLY ADAPTED THEREFOR
    • G03F9/00—Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically
    • G03F9/70—Registration or positioning of originals, masks, frames, photographic sheets or textured or patterned surfaces, e.g. automatically for microlithography
    • G03F9/7088—Alignment mark detection, e.g. TTR, TTL, off-axis detection, array detector, video detection

Definitions

  • the present disclosure relates to metrology systems, for example, an alignment system for measuring alignment mark positions in lithographic apparatuses and systems.
  • a lithographic apparatus is a machine that applies a desired pattern onto a substrate, usually onto a target portion of the substrate.
  • a lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs).
  • a patterning device which can be a mask or a reticle, can be used to generate a circuit pattern to be formed on an individual layer of the IC.
  • This pattern can be transferred onto a target portion (e.g., comprising part of, one, or several dies) on a substrate (e.g., a silicon wafer). Transfer of the pattern is typically via imaging onto a layer of radiationsensitive material (photoresist or simply “resist”) provided on the substrate.
  • photoresist radiationsensitive material
  • a single substrate will contain a network of adjacent target portions that are successively patterned.
  • lithographic apparatuses include so-called steppers, in which each target portion is irradiated by exposing an entire pattern onto the target portion at one time, and so-called scanners, in which each target portion is irradiated by scanning the pattern through a radiation beam in a given direction (the “scanning”- direction) while synchronously scanning the target portions parallel or anti-parallel to this scanning direction. It is also possible to transfer the pattern from the patterning device to the substrate by imprinting the pattern onto the substrate.
  • lithographic operation During lithographic operation, different processing steps can entail different layers to be sequentially formed on the substrate. Accordingly, it may be necessary to position the substrate relative to prior patterns formed thereon with a high degree of accuracy.
  • alignment marks are placed on the substrate to be aligned and are located with reference to a second object.
  • a lithographic apparatus can use an alignment apparatus for detecting positions of the alignment marks and for aligning the substrate using the alignment marks to ensure accurate exposure from a mask. Misalignment between the alignment marks at two different layers is measured as overlay error.
  • parameters of the patterned substrate are measured.
  • Parameters can include, for example, the overlay error between successive layers formed in or on the patterned substrate and critical linewidth of developed photosensitive resist. This measurement can be performed on a product substrate and/or on a dedicated metrology target.
  • a fast and non-invasive form of a specialized inspection tool is a scatterometer in which a beam of radiation is directed onto a target on the surface of the substrate and properties of the scattered or reflected beam are measured.
  • the properties of the substrate can be determined. This can be done, for example, by comparing the reflected beam with data stored in a library of known measurements associated with known substrate properties.
  • Spectroscopic scatterometers direct a broadband radiation beam onto the substrate and measure the spectrum (intensity as a function of wavelength) of the radiation scattered into a particular narrow angular range.
  • angularly resolved scatterometers use a monochromatic radiation beam and measure the intensity of the scattered radiation as a function of angle.
  • Such optical scatterometers can be used to measure parameters, such as critical dimensions of developed photosensitive resist or overlay error (OV) between two layers formed in or on the patterned substrate.
  • Properties of the substrate can be determined by comparing the properties of an illumination beam before and after the beam has been reflected or scattered by the substrate.
  • a detection system can measure a location of a peak of the alignment signal and can compare that peak location to an expected peak location to determine a position of an alignment mark on the substrate.
  • material inconsistencies can form a tilted resist covering the alignment marks.
  • the tilted resist can cause alignment signal degradation (e.g. a loss of Depth of Modulation), which can lead to alignment errors in the detection system.
  • an alignment system can include a radiation source, a self-referencing interferometer, a spatial filter assembly, a measurement device, and a detection system.
  • the radiation source can produce one or more illumination beams and direct the one or more illumination beams toward an alignment target on a wafer.
  • One or more diffraction beams can be reflected from the alignment target, wherein the one or more diffraction beams can include at least one positive diffraction order and one negative diffraction order.
  • the self-referencing interferometer can receive the one or more diffraction beams and generate an alignment signal including diffraction sub-beams, wherein the diffraction sub-beams are orthogonally polarized, rotated 180 degrees with respect to each other around an alignment axis, and are spatially overlapped.
  • the spatial filter assembly can restore a depth of modulation of the alignment signal.
  • the measurement device can measure a light intensity measurement of the alignment signal.
  • the detection system can determine a position of the alignment target based on the light intensity measurement of the alignment signal.
  • a lithographic apparatus can include an illumination system, a projection system, and an alignment system.
  • the illumination system can illuminate a patterning device.
  • the projection system can project an image of the patterning device onto a wafer.
  • the alignment system can include a radiation source, a self-referencing interferometer, a spatial filter assembly, a measurement device, and a detection system.
  • the radiation source can produce one or more illumination beams and direct the one or more illumination beams toward an alignment target on a wafer.
  • One or more diffraction beams can be reflected from the alignment target, wherein the one or more diffraction beams can include at least one positive diffraction order and one negative diffraction order.
  • the selfreferencing interferometer can receive the one or more diffraction beams and generate an alignment signal including diffraction sub-beams, wherein the diffraction sub-beams are orthogonally polarized, rotated 180 degrees with respect to each other around an alignment axis, and are spatially overlapped.
  • the spatial filter assembly can restore a depth of modulation of the alignment signal.
  • the measurement device can measure a light intensity measurement of the alignment signal.
  • the detection system can determine a position of the alignment target based on the light intensity measurement of the alignment signal.
  • a method can include producing, with a radiation source, one or more illumination beams.
  • the method can further include directing, with the radiation source, the one or more illumination beams toward an alignment target on a wafer.
  • the method can further include receiving, with a self-referencing interferometer, one or more diffraction beams reflected from the alignment target, wherein the one or more diffraction beams comprise at least one positive diffraction order and one negative diffraction order.
  • the method can further include generating, with the self-referencing interferometer, an alignment signal comprising diffraction sub-beams, wherein the diffraction subbeams are orthogonally polarized, rotated 180 degrees with respect to each other around an alignment axis, and are spatially overlapped.
  • the method can further include restoring, with a spatial filter assembly, a depth of modulation of the alignment signal.
  • the method can further include measuring, with a measurement device, a light intensity measurement of the alignment signal.
  • the method can further include determining, with a detection system, a position of the alignment target based on the light intensity measurement of the alignment signal.
  • FIG. 1A shows a reflective lithographic apparatus, according to some aspects.
  • FIG. IB shows a transmissive lithographic apparatus, according to some aspects.
  • FIG. 2 shows more details of a reflective lithographic apparatus, according to some aspects.
  • FIG. 3 shows a lithographic cell, according to some aspects.
  • FIGS. 4 A and 4B show inspection apparatuses, according to some aspects.
  • FIG. 5 shows a lithographic apparatus with a spatial filter assembly, according to some aspects.
  • FIG. 6 shows a spatial filter assembly with a reference grating, according to some aspects.
  • FIGS. 7A-7C show reference gratings, according to some aspects.
  • FIGS. 8A-8B show a depth of modulation of an alignment signal, according to some aspects.
  • FIG. 9 shows a lithographic apparatus with a pupil filter, according to some aspects.
  • FIGS. 10A-10B show pupil filters, according to some aspects.
  • FIG. 11 shows a method for restoring a depth of modulation of an alignment signal, according to some aspects.
  • spatially relative terms such as “beneath,” “below,” “lower,” “above,” “on,” “upper” and the like, can be used herein for ease of description to describe one element or feature’s relationship to another element(s) or feature(s) as illustrated in the figures.
  • the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures.
  • the apparatus can be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein can likewise be interpreted accordingly.
  • the terms “about,” “approximately,” or the like can be used herein to indicate the value of a given quantity that can vary based on a particular technology. Based on the particular technology, the terms “about,” “approximately,” or the like can indicate a value of a given quantity that varies within, for example, 10-30% of the value (e.g., ⁇ 10%, ⁇ 20%, or ⁇ 30% of the value).
  • a machine- readable medium can include any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computing device).
  • a machine-readable medium can include read only memory (ROM); random access memory (RAM); magnetic disk storage media; optical storage media; flash memory devices; electrical, optical, acoustical or other forms of propagated signals (e.g., carrier waves, infrared signals, digital signals, etc.), and others.
  • firmware, software, routines, and/or instructions can be described herein as performing certain actions. However, it should be appreciated that such descriptions are merely for convenience and that such actions result from computing devices, processors, controllers, or other devices executing the firmware, software, routines, instructions, etc.
  • the term “machine -readable medium” can be interchangeable with similar terms, for example, “computer program product,” “computer-readable medium,” “non-transitory computer- readable medium,” or the like.
  • non-transitory can be used herein to characterize one or more forms of computer readable media except for a transitory, propagating signal.
  • FIGS. 1A and IB show a lithographic apparatus 100 and a lithographic apparatus 100’, respectively, in which aspects of the present disclosure can be implemented.
  • Lithographic apparatus 100 and lithographic apparatus 100’ each include the following: an illumination system (illuminator) IL configured to condition a radiation beam B (for example, deep ultra violet or extreme ultra violet radiation); a support structure (for example, a mask table) MT configured to support a patterning device (for example, a mask, a reticle, or a dynamic patterning device) MA and connected to a first positioner PM configured to accurately position the patterning device MA; and, a substrate table (for example, a wafer table) WT configured to hold a substrate (for example, a resist coated wafer) W and connected to a second positioner PW configured to accurately position the substrate W.
  • an illumination system illumination system
  • IL for example, deep ultra violet or extreme ultra violet radiation
  • a support structure for example, a mask table
  • MT configured to support a pattern
  • Lithographic apparatus 100 and 100’ also have a projection system PS configured to project a pattern imparted to the radiation beam B by patterning device MA onto a target portion (for example, comprising one or more dies) C of the substrate W.
  • the patterning device MA and the projection system PS are reflective.
  • the patterning device MA and the projection system PS are transmissive.
  • the illumination system IL can include various types of optical components, such as refractive, reflective, catadioptric, magnetic, electromagnetic, electrostatic, or other types of optical components, or any combination thereof, for directing, shaping, or controlling the radiation beam B.
  • optical components such as refractive, reflective, catadioptric, magnetic, electromagnetic, electrostatic, or other types of optical components, or any combination thereof, for directing, shaping, or controlling the radiation beam B.
  • the support structure MT holds the patterning device MA in a manner that depends on the orientation of the patterning device MA with respect to a reference frame, the design of at least one of the lithographic apparatus 100 and 100’, and other conditions, such as whether or not the patterning device MA is held in a vacuum environment.
  • the support structure MT can use mechanical, vacuum, electrostatic, or other clamping techniques to hold the patterning device MA.
  • the support structure MT can be a frame or a table, for example, which can be fixed or movable. By using sensors, the support structure MT can ensure that the patterning device MA is at a desired position, for example, with respect to the projection system PS.
  • patterning device should be broadly interpreted as referring to any device that can be used to impart a radiation beam B with a pattern in its cross-section, such as to create a pattern in the target portion C of the substrate W.
  • the pattern imparted to the radiation beam B can correspond to a particular functional layer in a device being created in the target portion C to form an integrated circuit.
  • the patterning device MA can be transmissive (as in lithographic apparatus 100’ of FIG. IB) or reflective (as in lithographic apparatus 100 of FIG. 1A).
  • Examples of patterning devices MA include reticles, masks, programmable mirror arrays, or programmable LCD panels.
  • Masks are well known in lithography, and include mask types such as binary, alternating phase shift, or attenuated phase shift, as well as various hybrid mask types.
  • 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 tilted mirrors impart a pattern in the radiation beam B, which is reflected by a matrix of small mirrors.
  • projection system PS can encompass any type of projection system, including refractive, reflective, catadioptric, magnetic, electromagnetic and electrostatic optical systems, or any combination thereof, as appropriate for the exposure radiation being used, or for other factors, such as the use of an immersion liquid on the substrate W or the use of a vacuum.
  • a vacuum environment can be used for EUV or electron beam radiation since other gases can absorb too much radiation or electrons.
  • a vacuum environment can therefore be provided to the whole beam path with the aid of a vacuum wall and vacuum pumps.
  • Lithographic apparatus 100 and/or lithographic apparatus 100’ can be of a type having two (dual stage) or more substrate tables WT (and/or two or more mask tables).
  • the additional substrate tables WT can be used in parallel, or preparatory steps can be carried out on one or more tables while one or more other substrate tables WT are being used for exposure.
  • the additional table may not be a substrate table WT.
  • the lithographic apparatus can also be of a type wherein at least a portion of the substrate can be covered by a liquid having a relatively high refractive index, e.g., water, so as to fill a space between the projection system and the substrate.
  • a liquid having a relatively high refractive index e.g., water
  • An immersion liquid can also be applied to other spaces in the lithographic apparatus, for example, between the mask and the projection system. Immersion techniques are well known in the art for increasing the numerical aperture of projection systems.
  • immersion as used herein does not mean that a structure, such as a substrate, must be submerged in liquid.
  • a liquid can be located between the projection system and the substrate during exposure.
  • the illuminator IL receives a radiation beam from a radiation source SO.
  • the source SO and the lithographic apparatus 100, 100’ can be separate physical entities, for example, when the source SO is an excimer laser. In such cases, the source SO is not considered to form part of the lithographic apparatus 100 or 100’, and the radiation beam B passes from the source SO to the illuminator IL with the aid of a beam delivery system BD (in FIG. IB) including, for example, suitable directing mirrors and/or a beam expander.
  • the source SO can be an integral part of the lithographic apparatus 100, 100’ , for example, when the source SO is a mercury lamp.
  • a radiation system can comprise the source SO, the illuminator IL, and/or the beam delivery system BD.
  • the illuminator IL can include an adjuster AD (in FIG. IB) for adjusting the angular intensity distribution of the radiation beam.
  • AD adjuster
  • the illuminator IL can comprise various other components (in FIG. IB), such as an integrator IN and a condenser CO.
  • the illuminator IL can be used to condition the radiation beam B to have a desired uniformity and intensity distribution in its cross section.
  • the radiation beam B is incident on the patterning device (for example, mask) MA, which is held on the support structure (for example, mask table) MT, and is patterned by the patterning device MA.
  • the radiation beam B is reflected from the patterning device (for example, mask) MA.
  • the radiation beam B passes through the projection system PS, which focuses the radiation beam B onto a target portion C of the substrate W.
  • the substrate table WT can be moved accurately (for example, so as to position different target portions C in the path of the radiation beam B).
  • the first positioner PM and another position sensor IF1 can be used to accurately position the patterning device (for example, mask) MA with respect to the path of the radiation beam B.
  • Patterning device (for example, mask) MA and substrate W can be aligned using mask alignment marks Ml, M2 and substrate alignment marks Pl, P2.
  • the radiation beam B is incident on the patterning device (for example, mask MA), which is held on the support structure (for example, mask table MT), and is patterned by the patterning device. Having traversed the mask MA, the radiation beam B passes through the projection system PS, which focuses the beam onto a target portion C of the substrate W.
  • the projection system has a pupil conjugate PPU to an illumination system pupil IPU. Portions of radiation emanate from the intensity distribution at the illumination system pupil IPU and traverse a mask pattern without being affected by diffraction at the mask pattern and create an image of the intensity distribution at the illumination system pupil IPU.
  • the projection system PS projects an image of the mask pattern MP, where the image is formed by diffracted beams produced from the mark pattern MP by radiation from the intensity distribution, onto a photoresist layer coated on the substrate W.
  • the mask pattern MP can include an array of lines and spaces. A diffraction of radiation at the array and different from zeroth order diffraction generates diverted diffracted beams with a change of direction in a direction perpendicular to the lines. Undiffracted beams (i.e., so-called zeroth order diffracted beams) traverse the pattern without any change in propagation direction.
  • the zeroth order diffracted beams traverse an upper lens or upper lens group of the projection system PS, upstream of the pupil conjugate PPU of the projection system PS, to reach the pupil conjugate PPU.
  • the portion of the intensity distribution in the plane of the pupil conjugate PPU and associated with the zeroth order diffracted beams is an image of the intensity distribution in the illumination system pupil IPU of the illumination system IL.
  • the aperture device PD for example, is disposed at or substantially at a plane that includes the pupil conjugate PPU of the projection system PS.
  • the projection system PS is arranged to capture (e.g., using a lens or lens group L) the zeroth order diffracted beams, first order diffracted beams, and/or higher order diffracted beams (not shown).
  • dipole illumination for imaging line patterns extending in a direction perpendicular to a line can be used to utilize the resolution enhancement effect of dipole illumination.
  • first- order diffracted beams interfere with corresponding zeroth-order diffracted beams at the level of the wafer W to create an image of the line pattern MP at highest possible resolution and process window (i.e., usable depth of focus in combination with tolerable exposure dose deviations).
  • astigmatism aberration can be reduced by providing radiation poles (not shown) in opposite quadrants of the illumination system pupil IPU. Further, in some aspects, astigmatism aberration can be reduced by blocking the zeroth order beams in the pupil conjugate PPU of the projection system associated with radiation poles in opposite quadrants. This is described in more detail in US 7,511,799 B2, issued Mar. 31, 2009, which is incorporated by reference herein in its entirety.
  • the substrate table WT can be moved accurately (for example, so as to position different target portions C in the path of the radiation beam B).
  • the first positioner PM and another position sensor can be used to accurately position the mask MA with respect to the path of the radiation beam B (for example, after mechanical retrieval from a mask library or during a scan).
  • movement of the mask table MT can be realized with the aid of a long-stroke module (coarse positioning) and a short-stroke module (fine positioning), which form part of the first positioner PM.
  • movement of the substrate table WT can be realized using a long-stroke module and a short-stroke module, which form part of the second positioner PW.
  • the mask table MT can be connected to a short-stroke actuator or can be fixed.
  • Mask MA and substrate W can be aligned using mask alignment marks Ml, M2, and substrate alignment marks Pl, P2.
  • the substrate alignment marks (as illustrated) occupy dedicated target portions, they can be located in spaces between target portions (known as scribe-lane alignment marks). Similarly, in situations in which more than one die is provided on the mask MA, the mask alignment marks can be located between the dies.
  • Mask table MT and patterning device MA can be in a vacuum chamber V, where an in-vacuum robot IVR can be used to move patterning devices such as a mask in and out of vacuum chamber.
  • an out-of-vacuum robot can be used for various transportation operations, similar to the in-vacuum robot IVR.
  • Both the in-vacuum and out-of-vacuum robots can be calibrated for a smooth transfer of any payload (e.g., mask) to a fixed kinematic mount of a transfer station.
  • the lithographic apparatus 100 and 100’ can be used in at least one of the following modes: [0051] 1.
  • step mode the support structure (for example, mask table) MT and the substrate table WT are kept essentially stationary, while an entire pattern imparted to the radiation beam B is projected onto a target portion C at one time (i.e., a single static exposure).
  • the substrate table WT is then shifted in the X and/or Y direction so that a different target portion C can be exposed.
  • the support structure (for example, mask table) MT and the substrate table WT are scanned synchronously while a pattern imparted to the radiation beam B is projected onto a target portion C (i.e., a single dynamic exposure).
  • the velocity and direction of the substrate table WT relative to the support structure (for example, mask table) MT can be determined by the (de- jmagnification and image reversal characteristics of the projection system PS.
  • the support structure (for example, mask table) MT is kept substantially stationary holding a programmable patterning device, and the substrate table WT is moved or scanned while a pattern imparted to the radiation beam B is projected onto a target portion C.
  • a pulsed radiation source SO can be employed and the programmable patterning device is updated as needed after each movement of the substrate table WT or in between successive radiation pulses during a scan.
  • This mode of operation can be readily applied to maskless lithography that utilizes a programmable patterning device, such as a programmable mirror array.
  • lithographic apparatus 100 includes an extreme ultraviolet (EUV) source, which is configured to generate a beam of EUV radiation for EUV lithography.
  • EUV extreme ultraviolet
  • the EUV source is configured in a radiation system, and a corresponding illumination system is configured to condition the EUV radiation beam of the EUV source.
  • lithographic apparatus 100’ includes a deep ultraviolet (DUV) source, which is configured to generate a beam of DUV radiation for DUV lithography.
  • DUV deep ultraviolet
  • the DUV source is configured in a radiation system, and a corresponding illumination system is configured to condition the DUV radiation beam of the DUV source.
  • FIG. 2 shows the lithographic apparatus 100 in more detail, including the source collector apparatus SO, the illumination system IL, and the projection system PS.
  • the source collector apparatus SO is constructed and arranged such that a vacuum environment can be maintained in an enclosing structure 220 of the source collector apparatus SO.
  • An EUV radiation emitting plasma 210 can be formed by a discharge produced plasma source. EUV radiation can be produced by a gas or vapor, for example Xe gas, Li vapor, or Sn vapor in which EUV radiation emitting plasma 210 is created to emit radiation in the EUV range of the electromagnetic spectrum.
  • the EUV radiation emitting plasma 210 is created by, for example, an electrical discharge causing at least a partially ionized plasma.
  • Partial pressures of, for example, 10 Pa of Xe, Li, Sn vapor, or any other suitable gas or vapor can be used for efficient generation of the radiation.
  • a plasma of excited tin (Sn) (e.g., excited via a laser) is provided to produce EUV radiation.
  • the radiation emitted by the EUV radiation emitting plasma 210 is passed from a source chamber 211 into a collector chamber 212 via an optional gas barrier or contaminant trap 230 (in some cases also referred to as contaminant barrier or foil trap), which is positioned in or behind an opening in source chamber 211.
  • the contaminant trap 230 can include a channel structure.
  • Contamination trap 230 can also include a gas barrier or a combination of a gas barrier and a channel structure.
  • the contaminant trap or contaminant barrier 230 further indicated herein at least includes a channel structure.
  • the collector chamber 212 can include a radiation collector CO, which can be a so-called grazing incidence collector.
  • Radiation collector CO has an upstream radiation collector side 251 and a downstream radiation collector side 252. Radiation that traverses collector CO can be reflected off a grating spectral filter 240 to be focused in a virtual source point INTF.
  • the virtual source point INTF is commonly referred to as the intermediate focus, and the source collector apparatus is arranged such that the intermediate focus INTF is located at or near an opening 219 in the enclosing structure 220.
  • the virtual source point INTF is an image of the EUV radiation emitting plasma 210.
  • Grating spectral filter 240 is used in particular for suppressing infra-red (IR) radiation.
  • the radiation traverses the illumination system IL, which can include a faceted field mirror device 222 and a faceted pupil mirror device 224 arranged to provide a desired angular distribution of the radiation beam 221, at the patterning device MA, as well as a desired uniformity of radiation intensity at the patterning device MA.
  • the illumination system IL can include a faceted field mirror device 222 and a faceted pupil mirror device 224 arranged to provide a desired angular distribution of the radiation beam 221, at the patterning device MA, as well as a desired uniformity of radiation intensity at the patterning device MA.
  • More elements than shown can generally be present in illumination optics unit IL and projection system PS.
  • the grating spectral filter 240 can optionally be present, depending upon the type of lithographic apparatus. Further, there can be more mirrors present than those shown in the FIG. 2, for example there can be one to six additional reflective elements present in the projection system PS than shown in FIG. 2.
  • Collector optic CO is depicted as a nested collector with grazing incidence reflectors 253, 254, and 255, just as an example of a collector (or collector mirror).
  • the grazing incidence reflectors 253, 254, and 255 are disposed axially symmetric around an optical axis O and a collector optic CO of this type is preferably used in combination with a discharge produced plasma source, often called a DPP source.
  • FIG. 3 shows a lithographic cell 300, also sometimes referred to a lithocell or cluster, according to some aspects.
  • Lithographic apparatus 100 or 100’ can form part of lithographic cell 300.
  • Lithographic cell 300 can also include one or more apparatuses to perform pre- and post-exposure processes on a substrate. Conventionally these include spin coaters SC to deposit resist layers, developers DE to develop exposed resist, chill plates CH, and bake plates BK.
  • a substrate handler, or robot, RO picks up substrates from input/output ports I/Ol, I/O2, moves them between the different process apparatuses and delivers them to the loading bay LB of the lithographic apparatus 100 or 100’ .
  • alignment marks are generally provided on the substrate, and the lithographic apparatus includes one or more inspection apparatuses for accurate positioning of marks on a substrate.
  • These alignment apparatuses are effectively position measuring apparatuses.
  • Different types of marks and different types of alignment apparatuses and/or systems are known from different times and different manufacturers.
  • a type of system widely used in current lithographic apparatus is based on a self-referencing interferometer as described in U.S. Patent No. 6,961,116 (den Boef et al.). Generally marks are measured separately to obtain X- and Y-positions.
  • a combined X- and Y-measurement can be performed using the techniques described in U.S. Publication No.
  • FIG. 4A shows a cross-sectional view of an inspection apparatus 400 that can be implemented as a part of lithographic apparatus 100 or 100’, according to some aspects.
  • inspection apparatus 400 can be configured to align a substrate (e.g., substrate W) with respect to a patterning device (e.g., patterning device MA).
  • Inspection apparatus 400 can be further configured to detect positions of alignment marks on the substrate and to align the substrate with respect to the patterning device or other components of lithographic apparatus 100 or 100’ using the detected positions of the alignment marks.
  • Such alignment of the substrate can ensure accurate exposure of one or more patterns on the substrate.
  • the terms “inspection apparatus,” “metrology system,” or the like can be used herein to refer to, e.g., a device used for measuring a property of a structure (e.g., overlay sensor, critical dimension sensor, or the like), a device or system used in a lithographic apparatus to inspect an alignment of a wafer (e.g., alignment sensor), or the like.
  • a device used for measuring a property of a structure e.g., overlay sensor, critical dimension sensor, or the like
  • a device or system used in a lithographic apparatus to inspect an alignment of a wafer e.g., alignment sensor
  • inspection apparatus 400 can include an illumination system 412, a beam splitter 414, an interferometer 426, a detector 428, a beam analyzer 430, and a processor 432.
  • Illumination system 412 can be configured to provide an electromagnetic narrow band radiation beam 413 having one or more passbands.
  • the one or more passbands can be within a spectrum of wavelengths between about 500 nm to about 900 nm.
  • the one or more passbands can be discrete narrow passbands within a spectrum of wavelengths between about 500 nm to about 900 nm.
  • Illumination system 412 can be further configured to provide one or more passbands having substantially constant center wavelength (CWL) values over a long period of time (e.g., over a lifetime of illumination system 412).
  • CWL center wavelength
  • Such configuration of illumination system 412 can help to prevent the shift of the actual CWL values from the desired CWL values, as discussed above, in current alignment systems. And, as a result, the use of constant CWL values can improve long-term stability and accuracy of alignment systems (e.g., inspection apparatus 400) compared to the current alignment apparatuses.
  • beam splitter 414 can be configured to receive radiation beam 413 and split radiation beam 413 into at least two radiation sub-beams.
  • radiation beam 413 can be split into radiation sub-beams 415 and 417, as shown in FIG. 4A.
  • Beam splitter 414 can be further configured to direct radiation sub-beam 415 onto a substrate 420 placed on a stage 422.
  • the stage 422 is movable along direction 424.
  • Radiation sub-beam 415 can be configured to illuminate an alignment mark or a target 418 located on substrate 420.
  • Alignment mark or target 418 can be coated with a radiation sensitive film.
  • alignment mark or target 418 can have one hundred and eighty degrees (i.e., 180°) symmetry.
  • the target 418 on substrate 420 can be (a) a resist layer grating comprising bars that are formed of solid resist lines, or (b) a product layer grating, or (c) a composite grating stack in an overlay target structure comprising a resist grating overlaid or interleaved on a product layer grating.
  • the bars can alternatively be etched into the substrate.
  • This pattern is sensitive to chromatic aberrations in the lithographic projection apparatus, particularly the projection system PL, and illumination symmetry and the presence of such aberrations will manifest themselves in a variation in the printed grating.
  • One in-line method used in device manufacturing for measurements of line width, pitch, and critical dimension makes use of a technique known as “scatterometry”. Methods of scatterometry are described in Raymond et al., “Multiparameter Grating Metrology Using Optical Scatterometry”, J. Vac. Sci. Tech. B, Vol. 15, no. 2, pp. 361-368 (1997) and Niu et al., “Specular Spectroscopic Scatterometry in DUV Lithography”, SPIE, Vol.
  • beam splitter 414 can be further configured to receive diffraction radiation beam 419 and split diffraction radiation beam 419 into at least two radiation sub-beams, according to an aspect.
  • Diffraction radiation beam 419 can be split into diffraction radiation sub-beams 429 and 439, as shown in FIG. 4A.
  • beam splitter 414 is shown to direct radiation sub-beam 415 towards alignment mark or target 418 and to direct diffracted radiation sub-beam 429 towards interferometer 426, the disclosure is not so limiting. Other optical arrangements can be used to obtain the similar result of illuminating alignment mark or target 418 on substrate 420 and detecting an image of alignment mark or target 418.
  • interferometer 426 can be configured to receive radiation sub-beam 417 and diffracted radiation sub-beam 429 through beam splitter 414.
  • diffracted radiation sub-beam 429 can be at least a portion of radiation sub-beam 415 that can be reflected from alignment mark or target 418.
  • interferometer 426 comprises any appropriate set of optical-elements, for example, a combination of prisms that can be configured to form two images of alignment mark or target 418 based on the received diffracted radiation sub-beam 429. It should be appreciated that a good quality image need not be formed. It can be enough to have the features of alignment mark 418 resolved.
  • Interferometer 426 can be further configured to rotate one of the two images with respect to the other of the two images 180° and recombine the rotated and unrotated images interferometrically.
  • detector 428 can be configured to receive the recombined image via interferometer signal 427 and detect interference as a result of the recombined image when alignment axis 421 of inspection apparatus 400 passes through a center of symmetry (not shown) of alignment mark or target 418.
  • Such interference can be due to alignment mark or target 418 being 180° symmetrical, and the recombined image interfering constructively or destructively, according to an example aspect.
  • detector 428 can be further configured to determine a position of the center of symmetry of alignment mark or target 418 and consequently, detect a position of substrate 420.
  • alignment axis 421 can be aligned with an optical beam perpendicular to substrate 420 and passing through a center of image rotation interferometer 426.
  • Detector 428 can be further configured to estimate the positions of alignment mark or target 418 by implementing sensor characteristics and interacting with wafer mark process variations.
  • detector 428 determines the position of the center of symmetry of alignment mark or target 418 by performing one or more of the following measurements:
  • This data can be obtained using any type of alignment sensor, for example, a SMASH (SMart Alignment Sensor Hybrid) sensor, as described in U.S. Patent No. 6,961,116 that employs a selfreferencing interferometer with a single detector and four different wavelengths, and extracts the alignment signal in software, or Athena (Advanced Technology using High order ENhancement of Alignment), as described in U.S. Patent No. 6,297,876, which directs each of seven diffraction orders to a dedicated detector, which are both incorporated by reference herein in their entireties.
  • SMASH SMart Alignment Sensor Hybrid
  • beam analyzer 430 can be configured to receive and determine an optical state of diffracted radiation sub-beam 439.
  • the optical state can be a measure of beam wavelength, polarization, or beam profile.
  • Beam analyzer 430 can be further configured to determine a position of stage 422 and correlate the position of stage 422 with the position of the center of symmetry of alignment mark or target 418. As such, the position of alignment mark or target 418 and, consequently, the position of substrate 420 can be accurately known with reference to stage 422.
  • beam analyzer 430 can be configured to determine a position of inspection apparatus 400 or any other reference element such that the center of symmetry of alignment mark or target 418 can be known with reference to inspection apparatus 400 or any other reference element.
  • Beam analyzer 430 can be a point or an imaging polarimeter with some form of wavelength-band selectivity. In some aspects, beam analyzer 430 can be directly integrated into inspection apparatus 400, or connected via fiber optics of several types: polarization preserving single mode, multimode, or imaging, according to other aspects. [0082] In some aspects, beam analyzer 430 can be further configured to determine the overlay data between two patterns on substrate 420. One of these patterns can be a reference pattern on a reference layer. The other pattern can be an exposed pattern on an exposed layer. The reference layer can be an etched layer already present on substrate 420. The reference layer can be generated by a reference pattern exposed on the substrate by lithographic apparatus 100 and/or 100’.
  • the exposed layer can be a resist layer exposed adjacent to the reference layer.
  • the exposed layer can be generated by an exposure pattern exposed on substrate 420 by lithographic apparatus 100 or 100’.
  • the exposed pattern on substrate 420 can correspond to a movement of substrate 420 by stage 422.
  • the measured overlay data can also indicate an offset between the reference pattern and the exposure pattern.
  • the measured overlay data can be used as calibration data to calibrate the exposure pattern exposed by lithographic apparatus 100 or 100’, such that after the calibration, the offset between the exposed layer and the reference layer can be minimized.
  • beam analyzer 430 can be further configured to determine a model of the product stack profile of substrate 420, and can be configured to measure overlay, critical dimension, and focus of target 418 in a single measurement.
  • the product stack profile contains information on the stacked product such as alignment mark, target 418, or substrate 420, and can include mark process variation-induced optical signature metrology that is a function of illumination variation.
  • the product stack profile can also include product grating profile, mark stack profile, and mark asymmetry information.
  • An example of beam analyzer 430 is YieldstarTM, manufactured by ASML, Veldhoven, The Netherlands, as described in U.S. Patent No. 8,706,442, which is incorporated by reference herein in its entirety.
  • Beam analyzer 430 can be further configured to process information related to a particular property of an exposed pattern in that layer.
  • beam analyzer 430 can process an overlay parameter (an indication of the positioning accuracy of the layer with respect to a previous layer on the substrate or the positioning accuracy of the first layer with respective to marks on the substrate), a focus parameter, and/or a critical dimension parameter (e.g., line width and its variations) of the depicted image in the layer.
  • Other parameters are image parameters relating to the quality of the depicted image of the exposed pattern.
  • an array of detectors can be connected to beam analyzer 430, and allows the possibility of accurate stack profile detection as discussed below.
  • detector 428 can be an array of detectors.
  • the detector array a number of options are possible: a bundle of multimode fibers, discrete pin detectors per channel, or CCD or CMOS (linear) arrays.
  • CCD or CMOS linear arrays.
  • the use of a bundle of multimode fibers enables any dissipating elements to be remotely located for stability reasons.
  • Discrete PIN detectors offer a large dynamic range but each need separate pre-amps. The number of elements is therefore limited.
  • CCD linear arrays offer many elements that can be read-out at high speed and are especially of interest if phase-stepping detection is used.
  • a second beam analyzer 430’ can be configured to receive and determine an optical state of diffracted radiation sub-beam 429, as shown in FIG. 4B.
  • the optical state can be a measure of beam wavelength, polarization, or beam profile.
  • Second beam analyzer 430’ can be identical to beam analyzer 430.
  • second beam analyzer 430’ can be configured to perform one or more of the functions of beam analyzer 430, such as determining a position of stage 422 and correlating the position of stage 422 with the position of the center of symmetry of alignment mark or target 418.
  • the position of alignment mark or target 418 and, consequently, the position of substrate 420 can be accurately known with reference to stage 422.
  • Second beam analyzer 430’ can also be configured to determine a position of inspection apparatus 400, or any other reference element, such that the center of symmetry of alignment mark or target 418 can be known with reference to inspection apparatus 400, or any other reference element.
  • second beam analyzer 430’ can be directly integrated into inspection apparatus 400, or it can be connected via fiber optics of several types: polarization preserving single mode, multimode, or imaging, according to other aspects.
  • second beam analyzer 430’ and beam analyzer 430 can be combined to form a single analyzer (not shown) configured to receive and determine the optical states of both diffracted radiation sub-beams 429 and 439.
  • processor 432 receives information from detector 428 and beam analyzer 430.
  • Processor 432 can create a basic correction algorithm based on the information received from detector 428 and beam analyzer 430, including but not limited to the optical state of the illumination beam, the alignment signals, associated position estimates, and the optical state in the pupil, image, and additional planes.
  • the pupil plane is the plane in which the radial position of radiation defines the angle of incidence and the angular position defines the azimuth angle of the radiation.
  • Processor 432 can utilize the basic correction algorithm to characterize the inspection apparatus 400 with reference to wafer marks and/or alignment marks 418.
  • FIG. 5 shows a lithographic apparatus 500 with a spatial filter assembly, according to some aspects.
  • Lithographic apparatus 500 can be configured to measure a position of an alignment target.
  • lithographic apparatus 500 can represent a detailed view of inspection apparatus 400 (FIGS. 4A and 4B).
  • Lithographic apparatus 500 can be built as a part of lithographic apparatus 100 or 100', or can be built as a stand-alone unit in lithographic cell 300 and work together with other apparatuses during operation.
  • lithographic apparatus 500 can include an illumination system 502, a projection system 512, a self-referencing interferometer (SRI) 532, a beam analyzer 536, and a detection system 548.
  • SRI self-referencing interferometer
  • illumination system 502 can include a radiation source 504, an objective lens 508, and a mirror 510.
  • radiation source 504 can be configured to emit a spatially coherent illumination beam 506.
  • Illumination beam 506 can have an electromagnetic narrow band with one or more pass bands.
  • illumination beam 506 can be visible light or infrared light with a wavelength in a range between about 500 nm to about 700 nm, and about 700 nm to about 2 pm, respectively.
  • radiation source 504 can include one or more sources of radiation, each source producing one or more passbands within a spectrum of wavelengths between about 500 nm to about 2 pm.
  • illumination beam 506 can be a combination of the one or more passbands from the one or more sources of radiation and can have substantially continuous wavelengths.
  • the wavelength range of the illumination beam 506 can also include ultra-violet light.
  • objective lens 508 focuses illumination beam 506 onto mirror 510.
  • mirror 510 can be disposed at any angle to redirect illumination beam 506 toward projection system 512. It is known to a person skilled in the art that other focusing optical elements within an illumination system can also be used to provide a similar function.
  • projection system 512 of lithographic apparatus 500 can include a beam splitter 514 and an objective lens 516, and can be configured to direct illumination beam 506 towards an alignment target 518 and direct diffraction beams 530a, 530b diffracted from alignment target 518 towards self-referencing interferometer (SRI) 532.
  • illumination beam 506 can be directed with any incident angle towards the alignment target 518.
  • beam splitter 514 can be a spot mirror, formed by a transmissive cube with a reflective metal layer disposed in the center of the cube. It should be noted that even though beam splitter 514 is shown to reflect illumination beam 506 towards alignment target 518 and to transmit diffraction beams 530a, 530b towards SRI 532, the disclosure is not so limiting. It would be apparent to a person skilled in the relevant art that other optical arrangements may be used to obtain a similar result.
  • objective lens 516 focuses illumination beam 506 onto alignment target 518 and collects diffraction beams 530a, 530b reflected from alignment target 518. It is known to a person skilled in the art that other focusing optical systems can also be used to provide a similar function.
  • illumination system 502 and projection system 512 are not limited to their depicted positions. The positions of structures can vary as necessary, for example, as designed for a modular assembly.
  • a substrate 520 (e.g. a semiconductor wafer) can be disposed on a stage 522 that is adjustable (e.g., a support structure that can move).
  • alignment target 518 can be a structure formed on a substrate 520 through pattern transfer using a prior-level lithography mask (not shown). The material and film stack used for the formation of alignment target 518 can depend on the layout of alignment target 518 on the prior-level lithography mask and the processes that the substrate 520 went through. The design requirement for alignment target 518 (e.g., shape and size) can depend on the alignment system and alignment method used.
  • alignment target 518 can comprise a diffractive structure (e.g., a grating(s)).
  • Alignment target 518 can reflect, refract, diffract, scatter, or the like, radiation (e.g. illumination beam 506).
  • radiation e.g. illumination beam 506
  • scattered radiation can be collected by objective lens 516.
  • alignment target 518 can be made of or coated with a radiation sensitive film, for example, a photoresist (“resist”).
  • a radiation sensitive film for example, a photoresist (“resist”).
  • resist layer 524 disposed on the surface of substrate 520 can be considered a “tilted resist” or “wedged resist.” Resist tilt can occur in scribelanes of substrate 520 where alignment targets are located (e.g., alignment target 518).
  • a scribelane may form a trench on a surface of the substrate 520. The resist does not fill the trench uniformly when substrate 520 is covered with resist.
  • alignment target 518 can be located under an area with a tilted resist surface as shown in FIG. 5.
  • a thickness of resist layer 524 can be from about 10 pm to about 20 pm.
  • the thickness of resist layer 524 can be about 10 pm.
  • top surface 528 of resist layer 524 can have a tilt angle 526 of about 0 degrees to about 5 degrees.
  • resist layer 524 can have a tilt angle 526 of about 1 degree.
  • diffraction beams 530a, 530b from alignment target 518 include symmetrically distributed high orders of diffraction beams, for example, +1 and -1, +2 and -2, ..., +n and -n, respectively (where n is an integer greater than 2). Different orders of diffraction beams are spatially separated, depending on a diffraction angle.
  • diffraction beams 530a, 530b include at least one positive diffraction order or one negative diffraction order.
  • illumination beam 506 can be refracted by resist layer 524 before illumination beam 506 can properly illuminate alignment target 518.
  • diffraction beams 530a, 530b can reflect from alignment target 518 and can subsequently be refracted by resist layer 524 in an undesirable manner. Therefore, due to the refraction of illumination beam 506 and the reflection and refraction of diffraction beams 530a, 530b, the diffraction angles of higher order diffraction beams 530a, 530b (e.g., +1/-1, . . ., +m/-m, where m is any integer greater than one) with respect to an optical axis of lithographic apparatus 500 may not be equal. Accordingly, measurement of positions of alignment targets may be inaccurate when a tilted resist is present. For example, lithographic apparatus 500 may lose its alignment signal as a depth of modulation of the alignment signal decreases, as described further below.
  • a nonuniformity of top surface 528 can be detrimental to accurate operation of a lithographic apparatus.
  • the tilt angle 526 of top surface 528 and differing amounts of material across resist layer 524 can cause angular deviations in diffraction beams 530a, 530b due to Snell’s law.
  • phase deltas between the higher order diffraction beams 530a, 530b may be introduced due to non-equal diffraction angles or different optical path lengths between each pair of the higher order diffraction beams 530a, 530b (e.g., +1/-1, ..., +m/-m).
  • the phase delta may introduce an aligned position error proportional to the magnitude of the phase delta.
  • SRI 532 is configured to receive diffraction beams 530a, 530b and produce diffraction sub-beams 534a-534d.
  • SRI 532 can project two overlapping images of the alignment target 518 that are relatively rotated by 180°.
  • a pair of positive and negative diffraction orders of the diffraction beams 530a, 530b can generate two pairs of diffraction sub-beams 534a-534d, where each pair of the diffraction sub-beams 534a-534d includes spatially overlapped components from both of the positive and negative diffraction orders of the diffraction beams 530a, 530b.
  • SRI 532 For detection system 548 to acquire an accurately aligned position for substrate 520, SRI 532 needs to produce a symmetrical overlap of positive and negative diffraction beams 530a, 530b.
  • the amount of symmetrical overlap between diffraction beams 530a, 530b can directly relate to how much modulation is present in the light intensity of the alignment signal.
  • a depth of modulation DoM
  • DoM can indicate the strength of a sinusoidal signal. Therefore, analyzing the DoM can enable a lithographic apparatus 500 to pinpoint an aligned position of the alignment target 518 accurate to a fraction of a nanometer.
  • DoM can be calculated by finding the difference of the 99 th percentile of the alignment signal and the 1 st percentile of the alignment signal, and then dividing the difference by the 99 th percentile of the alignment signal.
  • resist layer 524 can shift a peak-to-peak distance for the sinusoidal signal of diffraction beam 530a relative to a peak-to-peak distance for the sinusoidal signal of diffraction beam 530b in the pupil plane.
  • diffraction beams 530a, 530b may not be symmetric with respect to the optical axis of lithographic apparatus 500. After duplication of the diffraction beams 530a, 530b in SRI 532, the two copies of the diffraction beams 530a, 530b may not overlap symmetrically and no symmetric interference can take place, thereby impairing the self-referencing process and reducing the DoM of the alignment signal.
  • SRI 532 can produce a standing wave pattern created from diffraction beams 530a, 530b in the field of view of an alignment sensor.
  • detection system 548 can interpret the asymmetrical overlap between diffraction beams 530a, 530b as a position shift deviation from the center of the optical axis of lithographic apparatus 500, resulting in an alignment error. Therefore, in some aspects, detection system 548 can receive a reduced alignment signal, which imposes a higher uncertainty (e.g., in nanometers) of a position of an alignment target. In some aspects, the alignment signal can be lost entirely. In some aspects, a tilt angle 526 of about one degree in resist layer 524 can cause lithographic apparatus 500 to lose the alignment signal.
  • beam analyzer 536 (e.g. beam analyzer 430) can be configured to permit diffraction sub-beams 534a, 534b to pass through toward mirror 538 and to reflect diffraction subbeams 534c, 534d toward objective lens 540b.
  • mirror 538 can reflect diffraction subbeams 534a, 534b toward objective lens 540a.
  • diffraction sub-beams 534a-534d pass through objective lenses 540a, 540b, respectively, configured to focus diffraction sub-beams 534a-534d toward spatial filter assemblies 542a, 542b, respectively.
  • a spatial filter assembly 542a, 542b can be disposed before field stops 544a, 544b, respectively.
  • an image of alignment target 518 can irradiate spatial filter assembly 542a, 542b at the output plane to generate an intensity signal as a function of a position of alignment target 518 on substrate 520.
  • a spatial filter assembly 542a, 542b can be configured to restore the depth of modulation of the alignment signal and can produce restored alignment signal 546a, 546b, as discussed below in regard to FIG. 6.
  • field stops 544a, 544b can be located at an output plane in an alignment system.
  • detection system 548 of lithographic apparatus 500 can measure a light intensity of restored alignment signal 546a, 546b, and therefore the depth of modulation of the alignment signal.
  • the detection system 548 can be configured to determine a position of the alignment target 518 based on the light intensity measurement of restored alignment signal 546a, 546b, where the light intensity is modulated to extract alignment information among other parameters of the lithographic apparatus 500.
  • FIG. 6 shows a spatial filter assembly 600 with a reference grating 602, according to some aspects.
  • spatial filter assembly 600 can represent a detailed view of spatial filter assembly 542a shown in FIG. 5. The below discussion can be applied to spatial filter assembly 542b and its respective input signals and output signals.
  • spatial filter assembly 600 can include a reference grating 602, a substrate 604, a moveable stage 608, and a multimode fiber 614.
  • spatial filter assembly 600 can include a reference grating 602 disposed at a field stop (e.g., field stops 544a, 544b shown in FIG. 5)) in an output plane of an alignment system.
  • reference grating 602 can restore DoM from about 0% to about 80% when reference grating 602 produces restored alignment signal 612 (e.g., restored alignment signal 546a, 546b shown in FIG. 5).
  • reference grating 602 can produce restored alignment signal 612 with an improved DoM for any tilt angle (e.g., tilt angle 526 shown in FIG. 5) for a resist layer (e.g., resist layer 524 shown in FIG. 5).
  • reference grating can produce restored alignment signal 612 for all colors simultaneously (e.g., 4C systems or 12 systems) because reference grating 602 is located in a field plane of lithographic apparatus 500.
  • reference grating 602 can include at least one of a ID X-direction filter, a ID Y-direction filter, a 2D X- and Y-direction filter, a binary filter, a gray filter, a spectral filter, or a combination.
  • reference grating 602 can be configured with a reference grating pitch corresponding to a target pitch of an alignment target (e.g., alignment target 518 shown in FIG. 5).
  • reference grating 602 can be optimized for a higher order target pitch of an alignment target without compromising self-referencing processes.
  • reference grating 602 can produce restored alignment signal 612 without compromising detection of alignment targets under a flat resist layer (e.g.
  • reference grating 602 can produce a restored alignment signal 612 with a DoM of 100% when tilt angle 526 of resist layer 524 is equal to 0.
  • reference grating 602 can be formed by etching reference grating 602 into substrate 604.
  • substrate 604 can be a reticle or a glass plate.
  • reference grating 602 can be formed by MEMS mirrors configured to change a period or a profile of reference grating 602, thereby tuning reference grating 602 for a target wavelength.
  • reference grating 602 can be formed by using acousto-optic tunable filters (AOTFs) or liquid crystal tunable filters (LCTFs), thereby transmitting a target wavelength while excluding other wavelengths.
  • AOTFs acousto-optic tunable filters
  • LCTFs liquid crystal tunable filters
  • a self-referencing interferometer e.g., SRI 532 shown in FIG. 5
  • a self-referencing interferometer can produce a standing wave pattern from diffraction beams (e.g., diffraction beams 530a, 530b shown in FIG. 5).
  • a signal produced by the self-referencing interferometer can have separate modulating regions that are out of phase relative to each other. Therefore, separating the modulating regions can restore the DoM of the alignment signal by blocking an out-of-phase signal to allow a sinusoidal modulated signal pass through to detection system 548.
  • reference grating 602 can filter out portions of diffraction subbeams 606a, 606b that do not contribute to the alignment signal of the alignment target 518.
  • reference grating 602 can recover the DoM of the alignment signal by separating two signals that spatially reside in different regions, thereby blocking the standing wave effect of the interference pattern and allowing a modulating signal to pass through reference grating 602.
  • reference grating 602 can be configured to block a first diffraction sub-beam 606a (e.g., diffraction sub-beam 534a shown in FIG.
  • reference grating 602 can increase the DoM of lithographic apparatus 500, thereby allowing detection of alignment signals at lower signal-to-noise levels.
  • a self-referencing interferometer e.g., SRI 532 shown in FIG. 5
  • SRI 532 a self-referencing interferometer
  • diffraction beams e.g., diffraction beams 530a, 530b shown in FIG. 5
  • it may be more effective to create an image of an alignment target (e.g., alignment target 518 shown in FIG. 5) at the output plane of the lithographic apparatus (e.g., lithographic apparatus 500 shown in FIG. 5) without relying on self-referencing processes.
  • reference grating 602 can be configured to form an interference pattern of the diffraction sub-beams 606a, 606b (e.g., diffraction sub-beams 534a, 534b shown in FIG. 5) regardless of any spatial overlap in a pupil plane of the alignment system.
  • a positive diffraction order and a negative diffraction order of diffraction sub-beams 606a, 606b can interfere on reference grating 602 at the output plane, irrespective of any shift of diffraction sub-beams 606a, 606b in the pupil plane.
  • reference grating 602 can operate in conjunction with a self-referencing interferometer (e.g., SRI 532 shown in FIG. 5). In some aspects, reference grating 602 can still produce restored alignment signal 612 without an self-referencing interferometer in the alignment system.
  • a self-referencing interferometer e.g., SRI 532 shown in FIG. 5
  • reference grating 602 can still produce restored alignment signal 612 without an self-referencing interferometer in the alignment system.
  • reference grating 602 within substrate 604 can be mounted on a moveable stage 608.
  • moveable stage can be a filter wheel or a mechatronic component.
  • moveable stage 608 can be configured to tune the reference grating pitch to the target pitch by adjusting the reference grating 602 with at least one of translational motion or rotational motion.
  • the translational motion can be in the X-Y plane.
  • the rotational motion can be in the X-Y plane, around the Z-axis.
  • moveable stage 608 can be controlled by a processor (e.g., processor 432) or a controller.
  • moveable stage 608 can be controlled based on measurement data from a beam position sensor 610.
  • beam position sensor 610 can be configured to measure a position of diffraction sub-beams 606a, 606b depending on a tilted resist layer (e.g. resist layer 524 shown in FIG. 5) and a pitch of an alignment target (e.g., alignment target 518 shown in FIG. 5).
  • the beam position sensor can output data indicative of the position to the processor or controller.
  • the processor or controller can actuate moveable stage 608 based on the output data to adjust to the position of the diffraction sub-beams produced by the tilted resist layer and the pitch of the alignment target.
  • operation of the moveable stage 608 can be preset based on predetermined values for the tilt angle 526 of resist layer 524.
  • the beam position sensor 610 can be omitted.
  • spatial filter assembly 600 can use multimode fiber 614 to transmit restored alignment signal 614 to detection system 548.
  • reference grating 602 can integrate energy from diffraction sub-beams 606a, 606b to create a single interference signal (e.g., restored alignment signal 612) that is illuminates multimode fiber 614 to carry restored alignment signal 612 to detection system 548.
  • multimode fiber 614 can spaced 10s or 100s of microns away from substrate 604 such that only reference grating 602 moves when actuated by moveable stage 608 while multimode fiber 614 remains fixed.
  • FIGS. 7A-7C show reference gratings 602a-602c, according to some aspects.
  • FIG. 7A shows reference grating 602a as a ID Y-direction filter, according to some aspects.
  • FIG. 7B shows reference grating 602b as a ID X-direction filter, according to some aspects.
  • FIG. 7C shows reference grating 602c as a 2D X- and Y-direction checkerboard filter, according to some aspects.
  • reference gratings 602a-602c can be alternate aspects of reference grating 602 shown in FIG. 6.
  • spatial filter assembly 542a can use reference grating 602a while spatial filter assembly 542b can use reference grating 602b. In some aspects, spatial filter assembly 542a can use reference grating 602b while spatial filter assembly 542b can use reference grating 602a. In either exemplary configuration, alignment system can read X-direction and Y-direction alignment targets by applying ID reference gratings to different channels. In some aspects, spatial filter assembly 542a, 542b can both use reference grating 602c to enable the alignment system to read X-direction and Y-direction alignment targets by applying 2D reference gratings to both channels.
  • any of reference gratings 602a-602c can be disposed on a movable stage (e.g., movable stage 608 shown in FIG. 6) configured to tune a pitch of any of reference gratings 602a-602c to a pitch of a target by adjusting any of reference gratings 602a-602c with at least one of translational motion or rotational motion.
  • a movable stage e.g., movable stage 608 shown in FIG. 6
  • FIGS. 8A-8B show a depth of modulation of an alignment signal, according to some aspects.
  • FIGS. 8A-8B plot the depth of modulation on a graph with a light intensity amplitude 802 on the Y- axis and a position 804 on the X-axis.
  • FIG. 8A shows a weak depth of modulation 800 of an alignment signal based on the presence of a tilted resist, according to some aspects.
  • a detection system e.g. detection system 548 shown in FIG. 5 can read power of integrated output as a function of alignment target position.
  • the presence of a tilted resist can produce a small modulation in an alignment signal, thereby increasing the difficulty for a detection system to extract positional information from the alignment signal.
  • a peak-to-valley distance between data point 806 and data point 808 can be low when poor DoM exists.
  • depth of modulation 800 can be about 8% when a tilt angle (e.g. tilt angle 526 shown in FIG. 5) is 1 degree, a thickness of tilted resist layer (e.g., resist layer 524 shown in FIG. 5) is 10 pm, an alignment target (e.g. alignment target 518 shown in FIG. 5) is 16 pm, and diffraction beams (e.g. diffraction beams 530a, 530b shown in FIG. 5) are +l st and -1 st order diffraction beams.
  • FIG. 8B shows a restored depth of modulation 800’ of an alignment signal based on the use of a spatial filter assembly (e.g., spatial filter assembly 542a, 542b shown in FIG. 5) counteracting the presence of a tilted resist, according to some aspects.
  • a peak-to-valley distance between data point 806’ and data point 808’ can be increased by the spatial filter assembly, thereby improving the DoM relative to depth of modulation 800.
  • the DoM improvement can vary based on a thickness of a resist layer, a tilt angle of the resist layer, and a size of an alignment target.
  • the DoM improvement can be greatest when a pitch of the reference grating matches a pitch of the alignment target.
  • a reference grating (e.g., reference grating 602a shown in FIG. 7A) optimized for a 16 pm alignment mark can produce a depth of modulation 800’ of about 76% when a tilt angle (e.g. tilt angle 526 shown in FIG. 5) is 1 degree, a thickness of tilted resist layer (e.g., resist layer 524 shown in FIG. 5) is 10 pm, an alignment target (e.g. alignment target 518 shown in FIG. 5) is 16 pm, and diffraction beams (e.g. diffraction beams 530a, 530b shown in FIG. 5) are +l st and -1 st order diffraction beams.
  • reference grating 602a can restore DoM from about 8% to about 76%.
  • FIG. 9 shows a lithographic apparatus with a pupil filter, according to some aspects.
  • the above discussion of lithographic apparatus 500 shown in FIG. 5 applies to lithographic apparatus 500’ shown in FIG. 9.
  • the aspects of lithographic apparatus 500 shown in FIG. 5, for example, and the aspects of lithographic apparatus 500’ shown in FIG. 9 may be similar. Similar reference numbers are used to indicate features of the aspects of lithographic apparatus 500 shown in FIG. 5 and the similar features of the aspects of lithographic apparatus 500’ shown in FIG. 9.
  • spatial filter assembly 542a’, 542b’ can include a pupil filter configured to collect overlapping diffraction sub-beams 534a-534d for one or more predetermined wavelengths.
  • the pupil filter can be disposed in collimated space in the pupil in front of an objective lens 540a, 540b in the alignment system.
  • the pupil filter can include multiple openings to filter the high order diffraction beams sub-beams 534a-534d before the diffraction beams sub-beams 534a-534d reach detection system 548.
  • pupil filter of spatial filter assembly 542a’, 542b’ can be compatible with any tilt angle 526 of resist layer 524.
  • spatial filter assembly 542a’, 542b’ can filter out portions of diffraction sub-beams 534a-534d that do not contribute to the alignment signal of the alignment target 518.
  • spatial filter assembly 542a’, 542b’ can recover the DoM of the alignment signal by separating two signals that spatially reside in different regions, thereby blocking the standing wave effect of the interference pattern and allowing a modulating signal to pass through spatial filter assembly 542a’, 542b’.
  • spatial filter assembly 542a’ can be configured to block a first diffraction sub-beam 534a and allow a second diffraction sub-beam 534b to pass through spatial filter assembly 542a’, 542b’ to transmit a restored (e.g., modulating) alignment signal 546a to detection system 548.
  • spatial filter assembly 542a’, 542b’ can increase the DoM of lithographic apparatus 500’, thereby allowing detection of alignment signals at lower signal-to-noise levels.
  • pupil filter of spatial filter assembly 542a’, 542b’ can recover DoM from about 8% to about 71%.
  • pupil filter of spatial filter assembly 542a’, 542b’ can be a rotating disk with openings optimized for a particular pitch.
  • the pupil filter can be configured to be tuned to a target pitch of alignment target 518 with at least one of translational motion or rotational motion.
  • FIGS. 10A-10B show pupil filters 1000a, 1000b, according to some aspects.
  • pupil filters 1000a, 1000b can be incorporated into spatial filter assembly 542a’, 542b’ shown in FIG. 9.
  • pupil filters 1000a, 1000b can include four or more openings configured to collect overlapping diffraction sub-beams for one or more predetermined wavelengths.
  • the four or more openings can have a spectral coating to allow only specific wavelengths or ranges of wavelengths at specific pupil positions.
  • the range of wavelengths can be visible light wavelengths from about 380 nm to about 750 nm.
  • the range of wavelengths can be visible light wavelengths from about 380 nm to about 750 nm.
  • the range of wavelengths can be visible light wavelengths from about 380 nm to about 750 nm.
  • the spectral coating 1002 on pupil filter 1000a shown in FIG. 10A can be a single color filter.
  • spectral coating 1002 can transmit a single wavelength.
  • spectral coating 1002 can transmit a single wavelength of 550 nm.
  • the spectral coatings on pupil filter 1000b shown in FIG. 10B can be a multicolor filter, wherein each coating transmits only a certain wavelength.
  • a spectral coating 1004 can transmit a first wavelength.
  • spectral coating 1004 can transmit a first wavelength of 550 nm.
  • a spectral coating 1006 can transmit a second wavelength.
  • spectral coating 1006 can transmit a second wavelength of 700 nm.
  • a spectral coating overlap 1008 can transmit both a first and second wavelength.
  • spectral coating overlap 1008 can transmit a first wavelength of 550 nm and a second wavelength of 700 nm.
  • FIG. 11 shows a method 1100 for restoring a depth of modulation of an alignment signal, according to some aspects.
  • a radiation source e.g., radiation source 504 shown in FIG. 5
  • one or more illumination beams e.g., illumination beam 506 shown in FIG. 5
  • the radiation source can direct the one or more illumination beams toward an alignment target (e.g., alignment target 518 shown in FIG. 5) on a wafer (e.g., substrate 520 shown in FIG. 5).
  • an alignment target e.g., alignment target 518 shown in FIG. 5
  • a wafer e.g., substrate 520 shown in FIG. 5
  • a self-referencing interferometer e.g., SRI 532 shown in FIG. 5
  • can receive one or more diffraction beams e.g., diffraction beams 530a, 530b
  • the one or more diffraction beams comprise at least one positive diffraction order and one negative diffraction order.
  • the self-referencing interferometer can generate an alignment signal comprising diffraction sub-beams (e.g., diffraction sub-beams 534a-534d shown in FIG. 5), wherein the diffraction sub-beams are orthogonally polarized, rotated 180 degrees with respect to each other around an alignment axis, and are spatially overlapped.
  • diffraction sub-beams e.g., diffraction sub-beams 534a-534d shown in FIG. 5
  • a spatial filter assembly (e.g., spatial filter assembly 542a, 542b shown in FIG. 5) can restore a depth of modulation of the alignment signal.
  • the spatial filter assembly can include a reference grating (e.g., reference grating 602 shown in FIG. 6) disposed at a field stop (e.g., field stops 544a, 544b shown in FIG. 5) in an output plane of an alignment system.
  • the reference grating can be configured to block a first diffraction sub-beam (e.g., diffraction sub-beam 606a shown in FIG.
  • the reference grating can be configured to form an interference pattern of the diffraction sub-beams regardless of any spatial overlap in a pupil plane of the alignment system.
  • a measurement device can measure a light intensity measurement of the alignment signal.
  • the detection system can determine a position of the alignment target based on the light intensity measurement of the alignment signal.
  • the method steps of FIG. 11 can be performed in any conceivable order and it is not required that all steps be performed. Moreover, the method steps of FIG. 11 described above merely reflect an example of steps and are not limiting. That is, further method steps and functions are envisaged based aspects described in reference to FIGS. 1A-10B.
  • An alignment system comprising: a radiation source configured to produce one or more illumination beams and direct the one or more illumination beams toward an alignment target on a wafer, wherein one or more diffraction beams are reflected from the alignment target, and the one or more diffraction beams comprise at least one positive diffraction order and one negative diffraction order; a self-referencing interferometer configured to receive the one or more diffraction beams and generate an alignment signal comprising diffraction sub-beams, wherein the diffraction sub-beams are orthogonally polarized, rotated 180 degrees with respect to each other around an alignment axis, and are spatially overlapped; a spatial filter assembly configured to restore a depth of modulation of the alignment signal; a measurement device configured to measure a light intensity measurement of the alignment signal; and a detection system configured to determine a position of the alignment target based on the light intensity measurement of the alignment signal.
  • the reference grating comprises at least one of a ID X- direction filter, a ID Y-direction filter, a 2D X- and Y-direction filter, a binary filter, a gray filter, or a spectral filter.
  • the spatial filter assembly further comprises a moveable stage configured to tune the reference grating pitch to the target pitch by adjusting the reference grating with at least one of translational motion or rotational motion.
  • the spatial filter assembly comprises a pupil filter with four or more openings configured to collect overlapping diffraction sub-beams for one or more predetermined wavelengths, the pupil filter disposed in front of an output lens in the alignment system and configured to be tuned to a target pitch of the alignment target with at least one of translational motion or rotational motion.
  • a lithographic apparatus comprising: an illumination system configured to illuminate a patterning device; a projection system configured to project an image of the patterning device onto a wafer; and; an alignment system comprising: a radiation source configured to produce one or more illumination beams and direct the one or more illumination beams toward an alignment target on the wafer, wherein one or more diffraction beams are reflected from the alignment target, and the one or more diffraction beams comprise at least one positive diffraction order and one negative diffraction order; a self-referencing interferometer configured to receive the one or more diffraction beams and generate an alignment signal comprising diffraction sub-beams, wherein the diffraction subbeams are orthogonally polarized, rotated 180 degrees with respect to each other around an alignment axis, and are spatially overlapped; a spatial filter assembly configured to restore a depth of modulation of the alignment signal; a measurement device configured to measure a light intensity measurement of the alignment signal; and a detection system configured to determine a
  • the spatial filter assembly comprises a reference grating disposed at a field stop in an output plane of the alignment system.
  • the reference grating comprises at least one of a ID X-direction filter, a ID Y-direction filter, a 2D X- and Y-direction filter, a binary filter, a gray filter, or a spectral filter.
  • the reference grating comprises a reference grating pitch corresponding to a target pitch of the alignment target.
  • the spatial filter assembly further comprises a moveable stage configured to tune the reference grating pitch to the target pitch by adjusting the reference grating with at least one of translational motion or rotational motion.
  • the spatial filter assembly comprises a pupil filter with four or more openings configured to collect overlapping diffraction sub-beams for one or more predetermined wavelengths, the pupil filter disposed in front of an output lens in the alignment system and configured to be tuned to a target pitch of the alignment target with at least one of translational motion or rotational motion. 17.
  • a method comprising: directing one or more illumination beams toward an alignment target on a wafer; receiving, with a self-referencing interferometer, one or more diffraction beams reflected from the alignment target, wherein the one or more diffraction beams comprise at least one positive diffraction order and one negative diffraction order; generating, with the self-referencing interferometer, an alignment signal comprising diffraction sub-beams, wherein the diffraction sub-beams are orthogonally polarized, rotated 180 degrees with respect to each other around an alignment axis, and are spatially overlapped; restoring, with a spatial filter assembly, a depth of modulation of the alignment signal; measuring, with a measurement device, a light intensity measurement of the alignment signal; and determining, with a detection system, a position of the alignment target based on the light intensity measurement of the alignment signal.
  • the spatial filter assembly comprises a reference grating disposed at a field stop in an output plane of an alignment system.
  • UV radiation for example, having a wavelength I of 365, 248, 193, 157 or 126 nm
  • extreme ultraviolet (EUV or soft X-ray) radiation for example, having a wavelength in the range of 5-100 nm such as, for example, 13.5 nm
  • hard X-ray working at less than 5 nm as well as particle beams, such as ion beams or electron beams.
  • UV refers to radiation with wavelengths of approximately 100-400 nm.
  • Vacuum UV, or VUV refers to radiation having a wavelength of approximately 100-200 nm.
  • Deep UV generally refers to radiation having wavelengths ranging from 126 nm to 428 nm, and in some aspects, an excimer laser can generate DUV radiation used within a lithographic apparatus. It should be appreciated that radiation having a wavelength in the range of, for example, 5-20 nm relates to radiation with a certain wavelength band, of which at least part is in the range of 5-20 nm.
  • lithographic apparatuses described herein can be used in other applications, for example, in the manufacture of integrated optical systems, guidance and detection patterns for magnetic domain memories, flat-panel displays, LCDs, thin-film magnetic heads, etc.
  • any use of the terms “wafer” or “die” herein can be considered as specific examples of the more general terms “substrate” or “target portion”, respectively.
  • a substrate can be processed before or after exposure in, for example, a track unit (a tool that typically applies a layer of resist to a substrate and develops the exposed resist) and/or a metrology unit. Where applicable, aspects disclosed herein can be applied to such and other substrate processing tools. Furthermore, a substrate can be processed more than once, for example in order to create a multi-layer IC, so that the term substrate used herein can also refer to a substrate that already contains multiple processed layers.
  • a topography in a patterning device defines the pattern created on a substrate.
  • the topography of the patterning device can be pressed into a layer of resist supplied to the substrate whereupon the resist is cured by applying electromagnetic radiation, heat, pressure or a combination thereof.
  • the patterning device is moved out of the resist leaving a pattern in it after the resist is cured.

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Abstract

L'invention concerne un système d'alignement qui comprend une source de rayonnement, un interféromètre à auto-référencement, un ensemble filtre spatial, un dispositif de mesure et un système de détection. La source de rayonnement produit un ou plusieurs faisceaux d'éclairage, dirige le ou les faisceaux d'éclairage vers une cible d'alignement sur une tranche. L'interféromètre à auto-référencement reçoit un ou plusieurs faisceaux de diffraction et génère un signal d'alignement comprenant des sous-faisceaux de diffraction, les sous-faisceaux de diffraction étant polarisés orthogonalement, tournés de 180 degrés les uns par rapport aux autres autour d'un axe d'alignement, et se chevauchant spatialement. L'ensemble filtre spatial restaure une profondeur de modulation du signal d'alignement. Le dispositif de mesure mesure une mesure d'intensité lumineuse du signal d'alignement. Le système de détection détermine une position de la cible d'alignement sur la base de la mesure d'intensité lumineuse du signal d'alignement.
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Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6297876B1 (en) 1997-03-07 2001-10-02 Asm Lithography B.V. Lithographic projection apparatus with an alignment system for aligning substrate on mask
US6961116B2 (en) 2002-06-11 2005-11-01 Asml Netherlands B.V. Lithographic apparatus, device manufacturing method, and device manufactured thereby
US7511799B2 (en) 2006-01-27 2009-03-31 Asml Netherlands B.V. Lithographic projection apparatus and a device manufacturing method
US20090195768A1 (en) 2008-02-01 2009-08-06 Asml Netherlands B.V. Alignment Mark and a Method of Aligning a Substrate Comprising Such an Alignment Mark
US8706442B2 (en) 2008-07-14 2014-04-22 Asml Netherlands B.V. Alignment system, lithographic system and method
US20160223920A1 (en) * 2013-10-09 2016-08-04 Asml Netherlands B.V. Polarization Independent Interferometer
US20220397833A1 (en) * 2019-08-09 2022-12-15 Asml Netherlands B.V. Phase modulators in alignment to decrease mark size
WO2023020791A1 (fr) * 2021-08-20 2023-02-23 Asml Netherlands B.V. Système optique de compensation pour surfaces non uniformes, système de métrologie, appareil lithographique et procédés associés

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6297876B1 (en) 1997-03-07 2001-10-02 Asm Lithography B.V. Lithographic projection apparatus with an alignment system for aligning substrate on mask
US6961116B2 (en) 2002-06-11 2005-11-01 Asml Netherlands B.V. Lithographic apparatus, device manufacturing method, and device manufactured thereby
US7511799B2 (en) 2006-01-27 2009-03-31 Asml Netherlands B.V. Lithographic projection apparatus and a device manufacturing method
US20090195768A1 (en) 2008-02-01 2009-08-06 Asml Netherlands B.V. Alignment Mark and a Method of Aligning a Substrate Comprising Such an Alignment Mark
US8706442B2 (en) 2008-07-14 2014-04-22 Asml Netherlands B.V. Alignment system, lithographic system and method
US20160223920A1 (en) * 2013-10-09 2016-08-04 Asml Netherlands B.V. Polarization Independent Interferometer
US20220397833A1 (en) * 2019-08-09 2022-12-15 Asml Netherlands B.V. Phase modulators in alignment to decrease mark size
WO2023020791A1 (fr) * 2021-08-20 2023-02-23 Asml Netherlands B.V. Système optique de compensation pour surfaces non uniformes, système de métrologie, appareil lithographique et procédés associés

Non-Patent Citations (3)

* Cited by examiner, † Cited by third party
Title
"ALIGNMENT SYSTEM, LITHOGRAPHIC APPARATUS, AND METHOD FOR A TILTED RESIST", vol. 714, no. 23, 31 August 2023 (2023-08-31), XP007151726, ISSN: 0374-4353, Retrieved from the Internet <URL:https://www.researchdisclosure.com/database/RD714023> [retrieved on 20230831] *
NIU ET AL.: "Specular Spectroscopic Scatterometry in DUV Lithography", SPIE, vol. 3677, 1999, XP000981735, DOI: 10.1117/12.350802
RAYMOND ET AL.: "Multiparameter Grating Metrology Using Optical Scatterometry", J. VAC. SCI. TECH. B, vol. 15, no. 2, 1997, pages 361 - 368, XP000729016, DOI: 10.1116/1.589320

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