Lithographic apparatus, detection system with parallel sensor and method - Patents.com

Abstract

The lithographic apparatus includes an illumination system, a projection system, and a detection system. The illumination system illuminates a pattern on a patterning device. The projection system projects an image of the pattern onto a substrate. The detection system includes a sensor and a substrate support structure arranged in parallel. The sensor performs inspection of targets on the substrate and moves in a first direction during periods between inspections. The substrate support structure supports and moves the substrate in a second direction opposite to the first direction while the sensor is moved in the first direction during periods.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to U.S. Patent Application No. 63 / 483,716, filed February 7, 2023, which is incorporated herein by reference in its entirety.

[0002]

[0002] The present disclosure relates to metrology, for example, to sensors used to detect targets on substrates in lithographic apparatus and systems. [Background technology]

[0003] A lithographic apparatus is a machine that applies a desired pattern onto a substrate, usually onto a target portion of the substrate. Lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs). In such cases, a patterning device, which may be a mask or 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 the substrate (e.g. a silicon wafer). Transfer of the pattern is typically via imaging onto a layer of radiation-sensitive material (photoresist or simply "resist") provided on the substrate. In general, a single substrate will contain a network of adjacent target portions that are successively patterned. Conventional lithographic apparatus include so-called steppers, in which each target portion is irradiated by exposing the entire pattern onto the target portion in one go, and so-called scanners, in which each target portion is irradiated by scanning a radiation beam across the pattern in a given direction (the "scan" direction) while synchronously scanning the target portion parallel or anti-parallel to the scan direction. It is also possible to transfer the pattern from the patterning device to the substrate by imprinting the pattern onto the substrate.

[0004] During lithography operations, different processing steps may involve different layers being formed sequentially on a substrate. Therefore, it may be necessary to position the substrate with high precision relative to previous patterns formed thereon. Typically, alignment marks are placed on the substrate to be aligned and are positioned relative to a second object. Lithography apparatuses may use alignment devices to detect the positions of the alignment marks and use the alignment marks to align the substrate to ensure accurate exposure from the mask. The deviation between the alignment marks in two different layers is measured as an overlay error.

[0005] To monitor the lithography process, parameters of the patterned substrate are measured. These parameters may include, for example, the overlay error between successive layers formed in or on the patterned substrate and the critical linewidth of the developed photosensitive resist. These measurements can be performed on the product substrate and / or on dedicated metrology targets. There are various techniques for measuring the microstructures formed in the lithography process, including the use of scanning electron microscopes and various specialized tools. A fast, non-invasive form of specialized inspection tool is a scatterometer, which directs a beam of radiation onto a target on the substrate surface and measures the properties of the scattered or reflected beam. By comparing the properties of the beam before and after it is reflected or scattered by the substrate, the properties of the substrate can be determined. This can be done, for example, by comparing the reflected beam to data stored in a library of known measurements associated with known substrate properties. A spectroscopic scatterometer directs a broadband beam of radiation onto the substrate and measures the spectrum (intensity as a function of wavelength) of the radiation scattered over a specific, narrow angular range. In contrast, an angularly resolved scatterometer uses a monochromatic radiation beam and measures the intensity of the scattered radiation as a function of angle.

[0006]

[0006] Such optical scatterometers can be used to measure parameters such as the critical dimensions of a developed photosensitive resist or the overlay error (OV) between two layers formed in or on a patterned substrate. The properties of the substrate can be determined by comparing the properties of the illumination beam before and after it has been reflected or scattered by the substrate.

[0007]

[0007] The efficiency of a lithography system can be limited by metrology systems that use fixed sensors to measure targets on a substrate sequentially, where time can be wasted by accelerating and decelerating the wafer stage between marks when measuring multiple marks using fixed sensors. Summary of the Invention

[0008]

[0008] Therefore, it is desirable to increase the efficiency of metrology systems, for example, to be able to perform the detection process faster based on the aspects described herein.

[0009] In some aspects, a lithographic apparatus includes an illumination system, a projection system, and a detection system. The illumination system is configured to illuminate a pattern of a patterning device. The projection system is configured to project an image of the pattern onto a substrate. The detection system includes a sensor and a substrate support structure arranged in parallel. The sensor is configured to perform inspection of a target on the substrate and to move in a first direction during a period between inspections. The substrate support structure is configured to support and move the substrate in a second direction opposite to the first direction while the sensor is moved in the first direction during the period.

[0010] In some aspects, a system includes a sensor and a substrate support structure arranged in parallel. The sensor is configured to perform inspection of a target on the substrate and to move in a first direction during a period between inspections. The substrate support structure is configured to support and move the substrate in a second direction opposite the first direction while the sensor is moved in the first direction during the period.

[0011]

[0011] In some aspects, a method includes performing an inspection of a target on a substrate using parallel-arranged sensors, moving the sensors in a first direction during a period between inspections, moving a substrate support structure for supporting the substrate in a second direction opposite to the first direction while the sensors are moved in the first direction during the period, and determining a measurement value based on the inspection.

[0012]

[0012] Further features of various aspects of the present disclosure are described in detail below with reference to the accompanying drawings. It should be noted that the present disclosure is not limited to the specific aspects described herein. Such aspects are presented herein for illustrative purposes only. Further aspects will be apparent to those skilled in the art based on the teachings contained herein. [Brief explanation of the drawings]

[0013]

[0013] The accompanying drawings, which are incorporated in and form part of this specification, illustrate the present disclosure and, together with the description, serve to further explain the principles of the present disclosure and enable those skilled in the art to make and use the embodiments described herein.

[0014] [Figure 1A] 1 illustrates a reflective lithographic apparatus according to some embodiments. [Figure 1B]

[0015] 1 illustrates a transmissive lithographic apparatus according to some embodiments. [Figure 2]

[0016] 1 illustrates further details of a reflective lithographic apparatus, according to some embodiments. [Figure 3]

[0017] 1 illustrates a lithography cell according to some embodiments. [Figure 4A]

[0018] 1 illustrates an inspection device according to some embodiments. [Figure 4B] 1 illustrates an inspection apparatus according to some embodiments. [Figure 5]

[0019] 1 illustrates a detection system according to some embodiments. [Figure 6]

[0020] 1 illustrates a substrate according to some embodiments. [Figure 7]

[0021] 1 illustrates a method for operating a detection system, according to some embodiments.

[0015]

[0022] Features of the present disclosure will become more apparent from the detailed description set forth below in conjunction with these drawings. In the drawings, like reference symbols identify corresponding elements throughout. In the drawings, like reference numbers generally indicate identical, functionally similar, and / or structurally similar elements. Furthermore, the left-most digit(s) of a reference number generally identifies the drawing in which that reference number first appears. Unless otherwise noted, the drawings provided throughout this disclosure should not be construed as drawings to scale. DETAILED DESCRIPTION OF THE INVENTION

[0016]

[0023] References to embodiments described herein, and to "one embodiment," "an embodiment," "exemplary embodiment," "example embodiment," and the like in the specification, indicate that the described embodiment may include a particular feature, structure, or characteristic, but not all embodiments may necessarily include that particular feature, structure, or characteristic. Furthermore, such phrases do not necessarily refer to the same embodiment. Furthermore, when a particular feature, structure, or characteristic is described in connection with one embodiment, it is understood that it is within the knowledge of one skilled in the art to bring about such feature, structure, or characteristic in connection with other embodiments, whether or not it is explicitly described.

[0017]

[0024] Spatially relative terms such as "beneath," "below," "lower," "above," "on," "upper," and the like may be used herein to facilitate the description of the relationship of one element or feature to another element or feature, as shown in the figures. Spatially relative terms are intended to encompass various orientations of the device in use or operation in addition to the orientation shown in the figures. The device may be otherwise oriented (rotated 90 degrees or at other orientations), and the spatially relative descriptors used herein may be similarly interpreted accordingly.

[0018]

[0025] Terms such as "about" and "approximately" can be used herein to indicate a given quantity value that can vary based on a particular technique. Based on a particular technique, terms such as "about" and "approximately" can indicate a given quantity value that varies within a range of, for example, 10% to 30% of the value (e.g., ±10%, ±20%, or ±30% of the value).

[0019]

[0026] Aspects of the present disclosure may be implemented in hardware, firmware, software, or any combination thereof. Aspects of the present disclosure may also be implemented as instructions stored on a computer-readable medium and readable and executable by one or more processors. A machine-readable medium may include any mechanism for storing or transmitting information in a form readable by a machine (e.g., a computing device). For example, a machine-readable medium may include read-only memory (ROM), random-access memory (RAM), magnetic disk storage media, optical storage media, flash memory devices, or electrical, optical, acoustic, or other forms of propagated signals (e.g., carrier waves, infrared signals, digital signals, etc.). Furthermore, firmware, software, routines, and / or instructions may be described herein as performing certain actions. However, it should be understood that such description is merely for convenience and that such actions are actually performed by a computing device, processor, controller, or other device executing the firmware, software, routines, instructions, etc. The term "machine-readable medium" may be interchangeable with similar terms, such as "computer program product," "computer-readable medium," "non-transitory computer-readable medium," etc. As used herein, the term "non-transitory" may be used to characterize one or more forms of computer-readable media other than transitory propagating signals.

[0020]

[0027] However, before describing such aspects in more detail, it is helpful to present an exemplary environment in which aspects of the present disclosure can be implemented.

[0021]

[0028] Exemplary Lithography System

[0022]

[0029] 1A and 1B show lithographic apparatus 100 and lithographic apparatus 100', respectively, in which aspects of the present disclosure can be implemented. Lithographic apparatus 100 and lithographic apparatus 100' each include: an illumination system (illuminator) IL configured to condition a radiation beam B (e.g., deep ultraviolet or extreme ultraviolet radiation); a support structure (e.g., a mask table) MT configured to support a patterning device (e.g., a mask, reticle, or dynamic patterning device) MA and connected to a first positioner PM configured to accurately position the patterning device MA; and a substrate table (e.g., a wafer table) WT configured to hold a substrate (e.g., a resist-coated wafer) W and connected to a second positioner PW configured to accurately position the substrate W. Lithographic apparatus 100 and 100' also include a projection system PS configured to project a pattern imparted to radiation beam B by patterning device MA onto a target portion C of the substrate W (e.g., comprising part of one or more dies). In lithographic apparatus 100, patterning device MA and projection system PS are reflective. In lithographic apparatus 100', patterning device MA and projection system PS are transmissive.

[0023]

[0030] The illumination system IL may include various types of optical components, such as refractive, reflective, catadioptric, magnetic, electromagnetic, electrostatic or other types of optical components, or any combination thereof, to direct, shape or control the radiation beam B.

[0024]

[0031] The support structure MT holds the patterning device MA in a manner that depends on the orientation of the patterning device MA relative to a reference frame, the design of at least one of lithographic apparatuses 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 may use mechanical, vacuum, electrostatic or other clamping techniques to hold the patterning device MA. The support structure MT may, for example, be a frame or a table, which may be fixed or movable. Using sensors, the support structure MT may ensure that the patterning device MA is at a desired position, for example with respect to the projection system PS.

[0025]

[0032] The term "patterning device" MA should be interpreted broadly to refer to any device that can be used to impart a radiation beam B with a pattern in its cross-section so as to create a pattern in a target portion C of a substrate W. The pattern imparted to the radiation beam B will correspond to a particular functional layer in a device being created in the target portion C to form an integrated circuit.

[0026]

[0033] Patterning device MA may be transmissive (such as lithographic apparatus 100′ in FIG. 1B) or reflective (such as lithographic apparatus 100 in 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 uses 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 to a radiation beam B, which is reflected by the matrix of small mirrors.

[0027]

[0034] The term "projection system" PS may include any type of projection system, including refractive, reflective, catadioptric, magnetic, electromagnetic, electrostatic optical systems, or any combination thereof, appropriate to the exposure radiation used, or other factors such as the use of an immersion liquid or the use of a vacuum on the substrate W. A vacuum environment may be used for EUV or electron beam radiation, as other gases may be too absorbing of the radiation or electrons. A vacuum environment may therefore be provided throughout the beam path using a vacuum wall and vacuum pumps.

[0028]

[0035] Lithographic apparatus 100 and / or lithographic apparatus 100' may be of a type having two (dual stage) or more substrate tables WT (and / or two or more mask tables). In such a "multi-stage" machine, the additional substrate tables WT may be used in parallel, or preparatory steps may be performed on one or more tables while one or more other substrate tables WT are being used for exposure. In some circumstances, the additional tables may not be substrate tables WT.

[0029]

[0036] The lithographic apparatus may 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), so as to fill 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 mask and the projection system. Immersion techniques are well known in the art for increasing the numerical aperture of projection systems. As used herein, the term "immersion" does not imply that a structure such as a substrate must be submerged in liquid. For example, a liquid may be disposed between the projection system and the substrate during exposure.

[0030]

[0037] 1A and 1B, the illuminator IL receives a radiation beam from a radiation source SO. The radiation source SO and the lithographic apparatus 100, 100' may be separate physical entities, for example if the radiation source SO is an excimer laser. In such a case, the radiation source SO is not considered to form part of the lithographic apparatus 100 or 100' and the radiation beam B is delivered from the radiation source SO to the illuminator IL using a beam delivery system BD ( FIG. 1B ), for example comprising appropriate directing mirrors and / or beam expanders. Alternatively, the radiation source SO may be an integral part of the lithographic apparatus 100, 100', for example if the radiation source SO is a mercury lamp. A radiation system may include the radiation source SO, the illuminator IL, and / or the beam delivery system BD.

[0031]

[0038] The illuminator IL may include an adjuster AD ( FIG. 1B ) for adjusting the angular intensity distribution of the radiation beam. Generally, at least the outer and / or inner radial extent (commonly referred to as “σ-outer” and “σ-inner,” respectively) of the intensity distribution in a pupil plane of the illuminator may be adjusted. In addition, the illuminator IL may comprise various other components ( FIG. 1B ), such as an integrator IN and a condenser CO. The illuminator IL can be used to condition the radiation beam B so that it has a desired uniformity and intensity distribution in its cross-section.

[0032]

[0039] Referring to Figure 1A, radiation beam B is incident on patterning device (e.g., mask) MA, which is held on support structure (e.g., mask table) MT, and is patterned by the patterning device MA. In lithographic apparatus 100, radiation beam B is reflected from patterning device (e.g., mask) MA. After reflecting from patterning device (e.g., mask) MA, radiation beam B passes through projection system PS, which focuses radiation beam B onto a target portion C of substrate W. Using a second positioner PW, and a position sensor IF2 (e.g., an interferometer device, a linear encoder, or a capacitive sensor), the substrate table WT can be precisely moved (e.g., to position different target portions C in the path of radiation beam B). Similarly, using a first positioner PM and another position sensor IF1, the patterning device (e.g., mask) MA can be accurately positioned with respect to the path of radiation beam B. Mask alignment marks M1, M2 and substrate alignment marks P1, P2 can be used to align the patterning device (e.g., mask) MA and substrate W.

[0033]

[0040] Referring to Figure 1B, a 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. Having traversed the mask MA, the radiation beam B passes through a projection system PS, which focuses the beam onto a target portion C of a substrate W. The projection system has a pupil PPU that is conjugate with the illumination system pupil IPU. A portion of the radiation emerges from the intensity distribution at the illumination system pupil IPU and traverses the mask pattern unaffected by diffraction at the mask pattern, producing an image of the intensity distribution at the illumination system pupil IPU.

[0034]

[0041] The projection system PS projects an image of the mask pattern MP, formed by diffracted beams generated from the mark pattern MP by radiation from the intensity distribution, onto a photoresist layer coated on the substrate W. For example, the mask pattern MP may include a line-and-space array. Diffraction of the radiation at the array, other than the zeroth-order diffraction, generates bypass diffracted beams redirected perpendicular to the lines. The undiffracted beams (i.e., the so-called zeroth-order diffracted beams) pass through the pattern without changing their direction of propagation. The zeroth-order diffracted beams pass through the upper lens or upper lens group of the projection system PS upstream of the pupil conjugate point PPU of the projection system PS and reach the pupil conjugate point PPU. The portion of the intensity distribution in the plane of the pupil conjugate point PPU associated with the zeroth-order diffracted beam is an image of the intensity distribution in the illumination system pupil IPU of the illumination system IL. For example, the aperture device PD is positioned or substantially positioned in a plane containing the pupil conjugate point PPU of the projection system PS.

[0035]

[0042] The projection system PS is positioned (e.g., using a lens or lens group L) to capture the zeroth-order diffracted beam, the first-order diffracted beam, and / or higher-order diffracted beams (not shown). In some embodiments, dipole illumination can be used to image a line pattern extending in a direction perpendicular to the line, taking advantage of the resolution-enhancing effect of dipole illumination. For example, a first-order diffracted beam interferes with a corresponding zeroth-order diffracted beam at the level of the wafer W to create an image of the line pattern MP with the highest possible resolution and process window (i.e., usable depth of focus combined with an acceptable exposure dose deviation). In some embodiments, astigmatism can be reduced by providing a radiation pole (not shown) in the opposite quadrant of the illumination system pupil IPU. Furthermore, in some embodiments, astigmatism can be reduced by blocking the zeroth-order beam at the projection system pupil conjugate point PPU associated with the radiation pole in the opposite quadrant. This is described in more detail in U.S. Patent No. 7,511,799, issued March 31, 2009, the entire contents of which are incorporated herein by reference.

[0036]

[0043] Using the second positioner PW and a position sensor IFD (e.g. an interferometer device, a linear encoder or a capacitive sensor), the substrate table WT can be accurately moved (e.g. to position different target portions C in the path of the radiation beam B). Similarly, using the first positioner PM and a further position sensor (not shown in FIG. 1B ), the mask MA can be accurately positioned with respect to the path of the radiation beam B (e.g. after mechanical retrieval from a mask library or during a scan).

[0037]

[0044] In general, movement of the mask table 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 mask table MT may be connected to a short-stroke actuator, or may be fixed. The mask MA and substrate W may be aligned using mask alignment marks M1, M2 and substrate alignment marks P1, P2. The substrate alignment marks (as shown) occupy dedicated target portions, but 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 mask MA, the mask alignment marks may be located between the dies.

[0038]

[0045] The mask table MT and patterning device MA may be within a vacuum chamber V, where an in-vacuum robot IVR can be used to move the patterning device, such as a mask, in and out of the vacuum chamber. Alternatively, if the mask table MT and patterning device MA are outside the vacuum chamber, an out-of-vacuum robot can be used for various transfer operations similar to the in-vacuum robot IVR. Both the in-vacuum and out-of-vacuum robots can be calibrated to smoothly transfer any payload (e.g., a mask) to a fixed kinematic mount in the transfer station.

[0039]

[0046] Lithographic apparatus 100 and 100' can be used in at least one of the following modes:

[0040]

[0047] 1. In step mode, the support structure (e.g. mask table) MT and substrate table WT are kept essentially stationary, while an entire pattern imparted to the radiation beam B is projected onto a target portion C in one go (i.e. a single static exposure), and the substrate table WT is then moved in the X and / or Y direction so that a different target portion C can be exposed.

[0041]

[0048] 2. In scan mode, the support structure (e.g. 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 (e.g. mask table) MT may be determined by the (de-)magnification and image reversal characteristics of the projection system PS.

[0042]

[0049] 3. In another mode, the support structure (e.g. mask table) MT holds a programmable patterning device and is held substantially stationary, while 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 is used, and the programmable patterning device is updated as required with each movement of the substrate table WT, or between successive radiation pulses during a scan. This mode of operation is readily adaptable to maskless lithography employing a programmable patterning device such as a programmable mirror array.

[0043]

[0050] Combinations and / or variations on the above described modes of use or entirely different modes of use may also be employed.

[0044]

[0051] In a further aspect, lithographic apparatus 100 includes an extreme ultraviolet (EUV) source configured to generate an EUV radiation beam for EUV lithography. Generally, 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.

[0045]

[0052] 2 shows lithographic apparatus 100 in more detail, including a source collector apparatus SO, an illumination system IL, and a projection system PS. The source collector apparatus SO is constructed and arranged such that a vacuum environment can be maintained within an enclosure 220 of the source collector apparatus SO. The EUV radiation-emitting plasma 210 can be formed by a discharge-produced plasma source. In some embodiments, a plasma of excited tin (Sn) (e.g., excited via a laser) is provided to produce EUV radiation.

[0046]

[0053] Radiation emitted by the EUV radiation-emitting plasma 210 is delivered from the source chamber 211 into the collector chamber 212 via an optional gas barrier or contaminant trap 230 (sometimes also referred to as a contaminant barrier or foil trap) positioned in or behind an opening in the source chamber 211. The contaminant trap 230 may include a channel structure. The contaminant trap 230 may also include a gas barrier or a combination of a gas barrier and a channel structure. The contaminant trap or contaminant barrier 230 further described herein includes at least a channel structure.

[0047]

[0054] The collector chamber 212 may include 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 into a virtual source point INTF. The virtual source point INTF is commonly called the intermediate focus, and the source collector arrangement is positioned such that the intermediate focus INTF is located at or near the opening 219 of the enclosure structure 220. The virtual source point INTF is an image of the EUV radiation emitting plasma 210. The grating spectral filter 240 is used to suppress, among other things, infrared (IR) radiation.

[0048]

[0055] The radiation then traverses an illumination system IL, which may 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, and to provide a desired radiation intensity uniformity at the patterning device MA. When the radiation beam 221 is reflected from the patterning device MA, which is held by a support structure MT, a patterned beam 226 is formed, which is imaged by the projection system PS via reflective elements 228, 229 onto a substrate W held by a wafer stage or substrate table WT.

[0049]

[0056] In general, there may be more elements in illumination optics unit IL and projection system PS than shown. Grating spectral filter 240 may optionally be present depending on the type of lithographic apparatus. Furthermore, there may be more mirrors than shown in Figure 2, for example, there may be one to six additional reflective elements in projection system PS compared to what is shown in Figure 2.

[0050]

[0057] 2 is shown as a nested collector with grazing incidence reflectors 253, 254, and 255, as just one example of a collector (or collector mirror). Grazing incidence reflectors 253, 254, and 255 are arranged axially symmetrically about optical axis O, and this type of collector system CO is suitable for use in combination with a discharge produced plasma source, often referred to as a DPP source.

[0051]

[0058] Exemplary Lithography Cell

[0052]

[0059] FIG. 3 illustrates a lithography cell 300, sometimes referred to as a lithocell or cluster, according to some embodiments. Lithography apparatus 100 or 100′ can form a portion of lithography cell 300. Lithography cell 300 may also include one or more devices that perform pre-exposure and post-exposure processes on a substrate. Conventionally, these include a spin coater SC for depositing a resist layer, a developer DE for developing exposed resist, a chill plate CH, and a bake plate BK. A substrate handler or robot RO picks up substrates from input / output ports I / O1, I / O2, moves them between different process tools, and delivers them to a loading bay LB of lithography apparatus 100 or 100′. These devices, often collectively referred to as a track, are under the control of a track control unit TCU, which is itself controlled by a supervisory control system SCS, which also controls the lithography apparatus via a lithography control unit LACU. Thus, the different devices can be operated to maximize throughput and processing efficiency.

[0053]

[0060] Exemplary Inspection Equipment

[0054]

[0061] To control the lithography process and accurately place device features on the substrate, alignment marks are typically provided on the substrate, and the lithography apparatus includes one or more inspection devices for accurate positioning of the marks on the substrate. These alignment devices are effectively position measurement devices. Different types of marks and different types of alignment devices and / or systems are known from different times and different manufacturers. A type of system widely used in current lithography apparatus is based on a self-referencing interferometer, as described in U.S. Pat. No. 6,961,116 (den Boef et al.). Typically, the marks are measured separately to obtain X and Y positions. Combined X and Y measurements may be performed using techniques described in U.S. Publication No. 2009 / 195768A (Bijnen et al.), the disclosures of both of which are incorporated herein by reference in their entirety.

[0055]

[0062] 4A shows a cross-sectional view of an inspection apparatus 400 that may be implemented as part of lithographic apparatus 100 or 100′, according to some embodiments. In some embodiments, inspection apparatus 400 may be configured to align a substrate (e.g., substrate W) relative to a patterning device (e.g., patterning device MA). Inspection apparatus 400 may further be configured to detect the positions of alignment marks on the substrate and use the detected positions of the alignment marks to align the substrate relative to a patterning device or other component of lithographic apparatus 100 or 100′. Aligning the substrate in this manner may ensure accurate exposure of one or more patterns on the substrate.

[0056]

[0063] Terms such as "inspection apparatus," "metrology system," and the like may be used herein to refer to, for example, devices used to measure characteristics of structures (e.g., overlay error, critical dimension parameters, etc.), devices or systems used in lithography apparatus to inspect the alignment of wafers (e.g., alignment sensors), and the like.

[0057]

[0064] In some embodiments, the inspection apparatus 400 may include an illumination system 412, a beam splitter 414, an interferometer 426, a detector 428, a beam analyzer 430, and an overlay calculation processor 432. The illumination system 412 may be configured to provide an electromagnetic narrowband radiation beam 413 having one or more passbands. In one example, the one or more passbands may be within a wavelength spectrum between about 500 nm and about 900 nm. In another example, the one or more passbands may be individual narrow passbands within a wavelength spectrum between about 500 nm and about 900 nm. The illumination system 412 may further be configured to provide one or more passbands having a substantially constant center wavelength (CWL) value over an extended period of time (e.g., over the lifetime of the illumination system 412). Such a configuration of the illumination system 412 can help prevent shifts in the actual CWL value from the desired CWL value in current alignment systems, as discussed above. Also, as a result, the use of a constant CWL value can improve the long-term stability and accuracy of the alignment system (eg, inspection tool 400) compared to current alignment tools.

[0058]

[0065] In some embodiments, beam splitter 414 may be configured to receive radiation beam 413 and split radiation beam 413 into at least two radiation sub-beams. For example, as shown in FIG. 4A , radiation beam 413 may be split into radiation sub-beams 415 and 417. Beam splitter 414 may be further configured to direct radiation sub-beam 415 onto a substrate 420 disposed on a stage 422. In one example, stage 422 is movable along direction 424. Radiation sub-beam 415 may be configured to illuminate an alignment mark or target 418 located on substrate 420. Alignment mark or target 418 may be coated with a radiation-sensitive film. In some embodiments, alignment mark or target 418 may have 180-degree (i.e., 180°) symmetry. That is, if the alignment mark or target 418 is rotated 180° about an axis of symmetry perpendicular to the plane of the alignment mark or target 418, the rotated alignment mark or target 418 may be substantially identical to the non-rotated alignment mark or target 418. The target 418 on the substrate 420 may be (a) a resist layer grating including bars 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. Alternatively, the bars can be etched into the substrate. This pattern is susceptible 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 variations in the printed grating. One in-line method used in device manufacturing for measuring line widths, pitches, and critical dimensions utilizes a technique known as “scatterometry.”Scatterometry methods 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. 3677 (1999), both of which are incorporated herein by reference in their entirety. In scatterometry, light is reflected by periodic structures in a target, and the resulting reflectance spectrum at a given angle is detected. The structures giving rise to the reflectance spectrum are reconstructed, for example, using rigorous coupled wave analysis (RCWA) or by comparison with a library of patterns derived by simulation. Thus, scatterometry data of the printed grating is used to reconstruct the grating. Grating parameters, such as line width and shape, may be input to the reconstruction process, performed by the processing unit PU, from knowledge of the printing step and / or other scatterometry processes.

[0059]

[0066] In some embodiments, beam splitter 414 may be further configured to receive diffracted radiation beam 419 and split diffracted radiation beam 419 into at least two radiation sub-beams according to an embodiment. As shown in Figure 4A, diffracted radiation beam 419 may be split into diffracted radiation sub-beams 429 and 439.

[0060]

[0067] It should be noted that although beam splitter 414 is shown directing radiation sub-beam 415 towards alignment mark or target 418 and diffracted radiation sub-beam 429 towards interferometer 426, the disclosure is not limited in this respect. Other optical configurations can be used to achieve similar results in illuminating alignment mark or target 418 on substrate 420 and detecting an image of alignment mark or target 418.

[0061]

[0068] 4A , interferometer 426 may be configured to receive radiation sub-beam 417 and diffracted radiation sub-beam 429 via beam splitter 414. In an exemplary embodiment, diffracted radiation sub-beam 429 may be at least a portion of radiation sub-beam 415 that may be reflected from alignment mark or target 418. In one example of this embodiment, interferometer 426 comprises any suitable set of optical elements, for example a combination of prisms, that may be configured to form two images of alignment mark or target 418 based on the received diffracted radiation sub-beam 429. It should be understood that good quality images need not be formed, but features of alignment mark 418 should be resolved. Interferometer 426 may further be configured to rotate one of the two images by 180° relative to the other, and interferometrically recombine the rotated and un-rotated images.

[0062]

[0069] In some embodiments, detector 428 may be configured to receive the recombined image via interferometer signal 427 and detect interference resulting from 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. According to an exemplary embodiment, such interference may result from alignment mark or target 418 being 180° symmetric, causing the recombined images to constructively or destructively interfere. Based on the detected interference, detector 428 may be further configured to determine the position of the center of symmetry of alignment mark or target 418 and, consequently, detect the position of substrate 420. According to one example, alignment axis 421 may be aligned with a light beam perpendicular to substrate 420 and passing through the center of image rotation interferometer 426. Detector 428 may be further configured to estimate the position of alignment mark or target 418 by implementing sensor characteristics and interacting with wafer mark process variations.

[0063]

[0070] In a further aspect, the detector 428 determines the location of the center of symmetry of the alignment mark or target 418 by performing one or more of the following measurements:

[0071] 1. Measuring the positional variation (positional shift between colors) for various wavelengths;

[0072] 2. Measuring the positional variation for the various orders (positional shift between diffraction orders), and

[0073] 3. Measuring the position variation (position shift between polarizations) for different polarizations.

[0064]

[0074] This data may be obtained using any type of alignment sensor, such as a SMASH (SMart Alignment Sensor Hybrid) sensor, as described in U.S. Pat. No. 6,961,116, which employs a self-referencing interferometer with a single detector and four different wavelengths and extracts the alignment signal in software, or an Athena (Advanced Technology using High order ENhancement of Alignment) sensor, as described in U.S. Pat. No. 6,297,876, which directs each of the seven diffraction orders to a dedicated detector, both of which are incorporated herein by reference in their entirety.

[0065]

[0075] In some aspects, the beam analyzer 430 may be configured to receive the diffracted radiation sub-beam 439 and determine its optical state. The optical state may be a measure of the beam wavelength, polarization, or beam profile. The beam analyzer 430 may further be configured to determine the position of the stage 422 and correlate the position of the stage 422 with the position of the center of symmetry of the alignment mark or target 418. Thus, the position of the alignment mark or target 418, and therefore the position of the substrate 420, may be precisely known relative to the stage 422. Alternatively, the beam analyzer 430 may be configured to determine the position of the inspection apparatus 400 or any other reference element such that the center of symmetry of the alignment mark or target 418 may be known relative to the inspection apparatus 400 or any other reference element. The beam analyzer 430 may be a point or imaging polarimeter with some form of wavelength band selectivity. In some embodiments, the beam analyzer 430 may be directly integrated into the inspection apparatus 400, or according to other embodiments, may be connected via some type of optical fiber, such as polarization-preserving single-mode, multimode, or imaging.

[0066]

[0076] In some embodiments, the beam analyzer 430 may be further configured to measure overlay data between two patterns on the substrate 420. One of these patterns may be a reference pattern on the reference layer. The other pattern may be an exposure pattern on the exposure layer. The reference layer may be an etched layer already present on the substrate 420. The reference layer may be generated by a reference pattern exposed on the substrate by the lithographic apparatus 100 and / or 100′. The exposure layer may be a resist layer exposed adjacent to the reference layer. The exposure layer may be generated by an exposure pattern exposed on the substrate 420 by the lithographic apparatus 100 or 100′. The exposure pattern on the substrate 420 may correspond to movement of the substrate 420 by the stage 422. In some embodiments, the measured overlay data may also indicate an offset between the reference pattern and the exposure pattern. The measured overlay data may be used as calibration data to calibrate the exposure pattern exposed by the lithographic apparatus 100 or 100′, so that after calibration, the offset between the exposure layer and the reference layer can be minimized.

[0067]

[0077] In some embodiments, the beam analyzer 430 may be further configured to determine a model of the product stack profile of the substrate 420 and may be configured to measure the overlay, critical dimensions, and focus of the target 418 in a single measurement. The product stack profile includes information about the stacked products, such as the alignment marks, the target 418, or the substrate 420, and may also include optical signature metrology induced by mark processing variations, which are a function of illumination variations. The product stack profile may also include product grating profiles, mark stack profiles, and mark asymmetry information. One example of a beam analyzer 430 is the Yieldstar™ manufactured by ASML, Veldhoven, The Netherlands, as described in U.S. Patent No. 8,706,442, which is incorporated herein by reference in its entirety. The beam analyzer 430 may also be configured to process information related to specific characteristics of the exposure pattern within that layer. For example, the beam analyzer 430 may process overlay parameters of the image rendered within that layer (a measure of the accuracy of positioning of that layer relative to the previous layer on the substrate, or the accuracy of positioning of the first layer relative to a mark on the substrate), focus parameters, and / or critical dimension parameters (e.g., line width and its variation). Other parameters include image parameters related to the quality of the rendered image of the exposure pattern.

[0068]

[0078] In some embodiments, a detector array (not shown) may be connected to the beam analyzer 430, allowing for the possibility of accurate stack profile detection, as discussed below. For example, the detector 428 may be an array of detectors. Several options are possible for the detector array: a multimode fiber bundle, individual pin detectors per channel, or a CCD or CMOS (linear) array. Using a multimode fiber bundle allows for the dissipative elements to be spaced apart for stability reasons. Individual PIN detectors offer a large dynamic range, but each may require a separate preamplifier. Therefore, the number of elements is limited. A CCD linear array provides a large number of elements that can be read out at high speed and is particularly advantageous when phase-stepping detection is used.

[0069]

[0079] In some embodiments, as shown in FIG. 4B , a second beam analyzer 430′ may be configured to receive the diffracted radiation sub-beam 429 and determine its optical state. The optical state may be a measure of beam wavelength, polarization, or beam profile. The second beam analyzer 430′ may be identical to the beam analyzer 430. Alternatively, the second beam analyzer 430′ may be configured to perform one or more functions of the beam analyzer 430, such as determining the position of the stage 422 and correlating the position of the stage 422 with the position of the center of symmetry of the alignment mark or target 418. Thus, the position of the alignment mark or target 418, and therefore the position of the substrate 420, may be precisely known relative to the stage 422. The second beam analyzer 430′ may also be configured to determine the position of the inspection apparatus 400 or any other reference element, such that the center of symmetry of the alignment mark or target 418 may be known relative to the inspection apparatus 400 or any other reference element. The second beam analyzer 430′ may be further configured to determine overlay data between the two patterns and a model of the product stack profile of the substrate 420. The second beam analyzer 430′ may also be configured to measure the overlay, critical dimensions, and focus of the target 418 in a single measurement.

[0070]

[0080] In some aspects, the second beam analyzer 430' may be directly integrated into the inspection apparatus 400, or according to other aspects, may be connected via some type of optical fiber, such as polarization-preserving single-mode, multimode, or imaging. Alternatively, the second beam analyzer 430' and the beam analyzer 430 may be combined to form a single analyzer (not shown) configured to receive both diffracted radiation sub-beams 429 and 439 and determine their optical states.

[0071]

[0081] In some embodiments, the processor 432 receives information from the detector 428 and the beam analyzer 430. For example, the processor 432 may be an overlay calculation processor. The information may include a model of the product stack profile constructed by the beam analyzer 430. Alternatively, the processor 432 can construct a model of the product mark profile using the received information about the product mark. In either case, the processor 432 uses or incorporates the model of the product mark profile to construct a model of the stacked product and overlay mark profile. The stack model is then used to determine the overlay offset and minimize spectral effects on the overlay offset measurement. The processor 432 can generate a basic correction algorithm based on information received from the detector 428 and the beam analyzer 430, including, but not limited to, the optical conditions of the illumination beam, the alignment signal, associated position estimates, and the optical conditions at the pupil plane, image plane, and additional planes. The pupil plane is the plane where the radial position of the radiation defines the angle of incidence and the angular position defines the azimuth angle of the radiation. The processor 432 may utilize its basic correction algorithms to characterize the inspection tool 400 with respect to the wafer marks and / or alignment marks 418 .

[0072]

[0082] In some embodiments, the processor 432 may be further configured to determine the printed pattern position offset error relative to the sensor estimate for each mark based on information received from the detector 428 and the beam analyzer 430. This information may include, but is not limited to, the product stack profile, overlay, critical dimension, and focus measurements for each alignment mark or target 418 on the substrate 420, etc. The processor 432 may utilize a clustering algorithm to group the marks into sets of similar constant offset errors and generate an alignment error offset correction table based on that information. The clustering algorithm may be based on additional optical stack processing information associated with each set of overlay measurements, position estimates, and offset errors. Overlay is calculated for multiple different marks, for example, overlay targets with positive and negative biases around the programmed overlay offset. The target measuring the smallest overlay is used as the reference (because it is measured with the highest accuracy). From this measured small overlay and the known programmed overlay of its corresponding target, the overlay error can be estimated. Table 1 shows how this may be done. In the example shown, the minimum overlay measured is -1 nm. However, this relates to a target with a programmed overlay of -30 nm. The process may have resulted in an overlay error of 29 nm.

[0073] [Table 1]

[0074]

[0083] The minimum value may be considered a reference point, against which the offset between the measured overlay and the predicted overlay due to the programmed overlay can be calculated. This offset determines the overlay error for each mark or a set of marks with a similar offset. Thus, in the example of Table 1, the minimum measured overlay was −1 nm at the target location where the programmed overlay was 30 nm. The difference between the predicted and measured overlays at other targets is compared to this reference. A table such as Table 1 may also be obtained from the marks and targets 418 under various illumination settings, and the illumination setting that results in the smallest overlay error and its corresponding calibration factor can be determined and selected. Following this, the processor 432 can group the marks into sets with similar overlay errors. The criteria for grouping the marks may be adjusted based on different process controls, e.g., different error tolerances for different processes.

[0075]

[0084] In some aspects, processor 432 can determine that all or most members of a group have similar offset errors and apply an individual offset correction from the clustering algorithm to each mark based on its additional optical stack metrology. Processor 432 can determine a correction value for each mark and feed the correction value back to lithographic apparatus 100 or 100′ to correct for overlay errors, for example, by providing the correction value to inspection apparatus 400.

[0076]

[0085] Exemplary Detection System

[0077]

[0086] In some aspects, the term "throughput" can be used to describe the rate at which wafers move through a particular manufacturing step and to the next. Throughput can be a performance marker that indicates the marketability of a lithography system. It is desirable for a lithography system to output as much product as possible in as little time as possible. Lithography manufacturing may include several complex processes. Each process involves technology choices that balance desired qualities (e.g., sub-nanometer accuracy, high yield, etc.) with drawbacks (e.g., slower production, cost). Such processes may include inspection of printed marks on a substrate. Detection systems may be used in conjunction with lithography processes, for example, to verify the conformance of a pattern printed on a substrate or to align a substrate to properly receive a new pattern. It should be appreciated that inspection processes can significantly improve mass production using lithography processes. It should also be appreciated that inspection processes have an associated time cost, which can reduce throughput.

[0078]

[0087] Some aspects herein include devices and features that improve the speed of the inspection process.

[0079]

[0088] 5 illustrates a detection system 500 according to some embodiments. In some embodiments, the detection system 500 can be implemented as part of the lithographic apparatus 100 or 100′ ( FIGS. 1A and 1B ). In some embodiments, the detection system 500 can include one or more sensor heads 506, each including a sensor 504 at a first end and an actuator 508 at a second end. In one example, one or more support bars 510 are configured to support each sensor head 506 at the first end of the sensor head 506. In some embodiments, an optical field 512 is shown used during measurement of the substrate 502.

[0080]

[0089] In some embodiments, first and second parallel support bars 510A and 510B are used, and eleven sensor heads 506 may be used. In one example, the first support bar 510A, shown above the second support bar 510B in the configuration of FIG. 5, is configured to hold five sensor heads 506 in a parallel relationship. In this example, the second support bar 510B is configured to hold six sensor heads 506 in a parallel relationship. Also in this example, the sensors 504 coupled to the first support bar 510A are offset relative to the sensors 504 coupled to the second support bar 510B. In operation, the support bars 510A and 510B move the sensors 504 across the substrate 502, as described below.

[0081]

[0090] As used herein, terms such as "detection system," "metrology system," and the like may be used to refer to, for example, devices used to measure characteristics of structures (e.g., overlay sensors, critical dimension sensors, etc.), devices or systems used to inspect the alignment of wafers in a lithography apparatus (e.g., alignment sensors), and the like.

[0082]

[0091] In some embodiments, the detection system 500 may include similar structure and functionality to the inspection apparatus 400 described with reference to FIGS. 4A and 4B . For example, the detection system 500 may be configured to align the substrate 502 with respect to a patterning device (not shown in FIG. 5 ). The detection system 500 may be further configured to perform an alignment process based on inspection of the positions of alignment marks or targets (not shown in FIG. 5 ) on the substrate 502. The detection system 500 may be further configured to align the substrate 502 with respect to a patterning device or other components of the lithographic apparatus 100 or 100′ ( FIGS. 1A and 1B ) using the detected positions of the alignment marks. Such alignment of the substrate 502 ensures accurate exposure of one or more patterns on the substrate 502. In another example, the detection system 500 may be configured to perform an overlay error analysis based on inspection of the alignment marks or targets.

[0083]

[0092] In some embodiments, the sensors 504 can be configured to perform inspection of alignment marks or targets on the substrate 502. Each sensor 504 can receive scattered radiation from multiple targets (e.g., as described with reference to FIGS. 4A and 4B). It should be noted that while FIGS. 4A and 4B show only one target (for clarity), a substrate 502 undergoing a lithography process can receive a pattern including multiple targets (e.g., tens or hundreds of gratings used in alignment and / or overlay inspection). The sensors 504 can generate measurement signals based on the scattered radiation from the targets.

[0084]

[0093] In some embodiments, each sensor 504 can be configured to be independently positionable. For example, each sensor head 506 can include an actuator 508 configured to adjust the position of each sensor 504 independently of the positions of the other sensors 504. When inspecting a different target, the sensors 504 can be actuated (e.g., reoriented, redirected, etc.) to select a different optical path. In some embodiments, each sensor 504 can be configured to have an adjustable speed of movement.

[0085]

[0094] In some embodiments, the detection system 500 can perform inspection measurements on multiple targets simultaneously. The sensors 504 can be arranged in a parallel array. In a parallel array, the sensors 504 can have m columns and n rows, where m and n are integer values ​​greater than or equal to 1. The sensors 504 can be arranged in an interleaved configuration for space efficiency. The sensors 504 can be distributed to match the layout of alignment marks or targets on the substrate 502. In this exemplary configuration, the parallel array of sensors 504 can increase throughput efficiency by performing multiple inspections simultaneously.

[0086]

[0095] In some embodiments, the sensor 504 may be configured to move in a first direction 514 during periods between inspections of the targets. In some embodiments, a substrate support structure (e.g., a wafer table WT (FIGS. 1A and 1B)) may be configured to support and move the substrate 502 in a second direction 516 opposite the first direction 514 while the sensor 504 is moved in the first direction 514 during periods. For example, relative motion between the targets and the sensor 504 (as indicated by the double arrow in FIG. 5) may be generated between inspections to align each successive row of the targets with a row of the sensor 504.

[0087]

[0096] In this manner, the time period for relative motion between the target and the sensor 504 can be significantly reduced compared to using a fixed single sensor. In metrology systems relying on a fixed single sensor, when the metrology system inspects multiple targets, the fixed single sensor can be moved from one target to another (e.g., by moving the substrate stage to bring each target into the field of view of the fixed single sensor, one at a time). In a single-sensor metrology system, the time it takes for the fixed single sensor to move from target to target can cause delays in device fabrication on the substrate 502. The time it takes to accelerate and decelerate inertial components and to precisely align the optics to the target can make such delays non-negligible. In some embodiments, the total delay of repeated accelerations and decelerations can be significant.

[0088]

[0097] In some embodiments, the detection system 500 can perform inspections when the motion of the movable device is in a stable phase of its motion (e.g., minimal acceleration and / or jitter). It should be understood that a movable device that begins and ends in a stationary state can have at least two phases of motion, e.g., an acceleration phase and a deceleration phase. There may also be a constant velocity phase and a combination of phases. It should be understood that instabilities such as jitter and vibrations may also exist during motion. For example, as a moving object approaches a set speed, there may be some final jitter due to the transient from full speed to a stop. In some embodiments, the detection system 500 can perform measurements during a stable period of motion. Additionally, predictable or measurable jitter can be applied as a correction to the measurements, for example, using a transfer function.

[0089]

[0098] In some embodiments, the detection system 500 can perform an inspection during a stabilization phase of operation. For example, the sensor 504 and the substrate support structure for the substrate 502 can be configured to move in a first direction 514 and a second direction 516, respectively, while the sensor 504 is performing an inspection. The first direction 514 can be different (e.g., opposite) from the second direction 516. The detection system 500 can perform an inspection continuously by minimizing the time spent in acceleration, deceleration, and / or stabilization phases. In this manner, measurement speed can be increased, further improving throughput.

[0090]

[0099] In some embodiments, a projection system (e.g., the PS in FIGS. 1A and 1B) can be configured to project an image of a pattern onto a substrate 502. The projection system can be configured to move in a first direction during periods between exposures of the substrate with the pattern and while the substrate 502 is moved in a second direction opposite the first direction. In this manner, the exposure speed can be increased, further improving throughput.

[0091]

[0100] 6 illustrates, according to some embodiments, the placement of targets 620 on a substrate 602. In some embodiments, the targets 620 may be, for example, alignment marks.

[0092]

[0101] In some embodiments, the targets 620 can be arranged in an array configuration of m columns and n rows, where m and n are integer values ​​greater than or equal to 1. In some embodiments, the array configuration can be polygonal. In some embodiments, the array configuration can be circular. For example, the array configuration can conform to the shape of a circle or ellipse, such as the surface area of ​​the substrate 602.

[0093]

[0102] In some embodiments, one or more targets 620 may fall within one or more corresponding sensor fields 622. The sensor fields 622 may correspond to sensors 504 (FIG. 5). When the substrate 602 and sensors 504 (FIG. 5) are moved, each sensor field 622 may be aligned with a corresponding one of the targets 620.

[0094]

[0103] FIG. 7 illustrates a method 700 according to some embodiments.

[0095]

[0104] In some embodiments, step 702 may perform inspection of targets on a substrate using multiple sensors, such as sensors 504, arranged, for example, as shown in FIG.

[0096]

[0105] In some embodiments, in step 704, the sensor may be moved in a first direction during the period between tests.

[0097]

[0106] In some embodiments, a substrate support structure for supporting the substrate may be moved in a second direction while the sensor may be moved in a first direction in step 706. In one embodiment, the second direction may be opposite to the first direction.

[0098]

[0107] In some embodiments, step 708 may determine measurements based on the test.

[0099]

[0108] The method steps in FIG. 7 can be performed in any conceivable order, and not all steps need to be performed. Furthermore, the method steps in FIG. 7 described above merely reflect example steps and are not limiting. That is, additional method steps and functions are contemplated based on the aspects described with reference to FIGS. 1A, 1B, 2, 3, 4A, 4B, 5, and 6. For example, the method may include moving the sensor and the substrate support structure in a first direction and a second direction, respectively, while the sensor performs an inspection. The method may include adjusting the position, movement speed, or position and movement speed of at least one sensor independently of the other sensors. The method may include performing an alignment process based on the inspection. The method may include performing an overlay error analysis based on the inspection.

[0100]

[0109] The embodiments can be further described using the following clauses. 1. A lithographic apparatus comprising: an illumination system configured to illuminate a pattern on a patterning device; a projection system configured to project an image of the pattern onto the substrate; a detection system, the detection system comprising: Parallel arranged sensors, Performing an inspection of the targets on the substrate; and Move in the first direction during the period between tests a sensor configured as follows: a substrate support structure configured to support and move the substrate in a second direction opposite the first direction while the sensor is moved in the first direction for a period of time. 2. The apparatus of clause 1, wherein the sensor and the substrate support structure are configured to move in a first direction and a second direction, respectively, while the sensor is performing the inspection. 3. The apparatus of clause 1, wherein each sensor is configured to be individually positionable. 4. The apparatus of clause 3, wherein each sensor includes an actuator configured to adjust each sensor independently of the other sensors. 5. The apparatus of clause 1, wherein each sensor is configured to have an adjustable speed of movement. 6. The apparatus of clause 1, wherein the detection system is configured to perform an alignment process based on the inspection. 7. The apparatus of clause 1, wherein the detection system is configured to perform overlay error analysis based on the inspection. 8. The apparatus of clause 1, wherein the projection system is configured to move in a first direction during periods between exposures of the substrate with the pattern and while the substrate is moved in a second direction opposite the first direction. 9. A system comprising: Parallel arranged sensors, Performing an inspection of the targets on the substrate; and Move in the first direction during the period between tests a sensor configured as follows: a substrate support structure configured to support and move the substrate in a second direction opposite the first direction while the sensor is moved in the first direction during a period of time; A system comprising: 10. The system of clause 9, wherein the sensor and the substrate support structure are configured to move in a first direction and a second direction, respectively, while the sensor performs an inspection of a target on the substrate. 11. The system of clause 9, wherein each sensor is configured to be individually positionable. 12. The system of clause 11, wherein each sensor includes an actuator configured to adjust each sensor independently of the other sensors. 13. The system of clause 9, wherein each sensor is configured to have an adjustable speed of movement. 14. The system of clause 9, wherein the system is configured to perform an alignment process based on the inspection. 15. The system of clause 9, wherein the system is configured to perform overlay error analysis based on the inspection. 16. Performing an inspection of a target on a substrate using parallel-arranged sensors; moving the sensor in a first direction during a period between tests; moving a substrate support structure for supporting the substrate in a second direction opposite the first direction while the sensor is moved in the first direction during a period of time; and determining a measurement based on the test. 17. The method of clause 16, further comprising moving the sensor and the substrate support structure in a first direction and a second direction, respectively, while the sensor is performing the inspection. 18. The method of clause 16, further comprising adjusting the position, rate of movement, or position and rate of movement of at least one sensor independently of other sensors. 19. The method of clause 16, further comprising performing an alignment process based on the inspection. 20. The method of clause 16, further comprising performing an overlay error analysis based on the inspection.

[0101]

[0110] Although specific reference may be made herein to the use of lithographic apparatus in the manufacture of ICs, it should be understood that the lithographic apparatus described herein have other applications, such as the manufacture of integrated optical systems, guidance and detection patterns for magnetic domain memories, flat panel displays, LCDs, thin film magnetic heads, etc. In light of these alternative applications, those skilled in the art will recognize that the use of the terms "wafer" or "die" herein may be considered specific instances of the more general terms "substrate" and "target portion," respectively. The substrates described herein may be processed, before or after exposure, in, for example, a track unit (a tool that typically applies a layer of resist to the substrate and develops the exposed resist) and / or a metrology unit. Where applicable, the disclosure herein may apply to such and other substrate processing tools. Furthermore, a substrate may be processed multiple times, for example to create multi-layer ICs, and thus the term substrate, as used herein, may also refer to a substrate that already includes multiple processing layers.

[0102]

[0111] Although specific reference has been made to the use of aspects of the present disclosure in the field of optical lithography, it should be understood that the present disclosure may also be used in other applications, for example imprint lithography, depending on the context, and is not limited to optical lithography. In imprint lithography, a topography in a patterning device defines the pattern created on a substrate. The topography of the patterning device is imprinted into a layer of resist supplied to the substrate and the resist is cured by applying electromagnetic radiation, heat, pressure or a combination thereof. The patterning device is then removed from the resist leaving a pattern in it when the resist is cured.

[0103]

[0112] It is to be understood that the terms or terminology used herein are for purposes of description and not of limitation, as the terms or terminology of the present disclosure would be interpreted by one of ordinary skill in the art in light of the teachings herein.

[0104]

[0113] The terms "radiation," "beam," "light," "illumination," and the like can be used herein to refer to one or more types of electromagnetic radiation, such as ultraviolet (UV) radiation (e.g., having a wavelength λ of 365, 248, 193, 157, or 126 nm), extreme ultraviolet (EUV or soft X-ray) radiation (e.g., having a wavelength in the range of 5 to 100 nm, such as 13.5 nm), or hard X-ray operating below 5 nm, as well as particle beams such as ion beams or electron beams. Generally, radiation having a wavelength between about 400 and about 700 nm is considered to be visible radiation, and radiation having a wavelength between about 780 and 3000 nm (or longer) is considered to be IR radiation. UV refers to radiation having a wavelength between approximately 100 and 400 nm. In lithography, the term "UV" also applies to wavelengths that can be produced by mercury discharge lamps: G-line 436 nm, H-line 405 nm, and / or I-line 365 nm. Vacuum UV or VUV (i.e., UV absorbed by gases) refers to radiation having a wavelength of approximately 100-200 nm. Deep UV (DUV) generally refers to radiation having a wavelength in the range of 126 nm to 428 nm, and in some embodiments, excimer lasers can generate DUV radiation for use in lithography equipment. It should be understood that radiation having a wavelength in the range of, for example, 5-20 nm, refers to radiation in a particular wavelength band, at least a portion of which is in the 5-20 nm range.

[0105]

[0114] The present disclosure has been described above using functional components and their relationships illustrating implementation of specific functions. The boundaries of these functional components have been arbitrarily defined herein for the convenience of description. Alternative boundaries may be defined so long as the specific functions and their relationships are appropriately performed. The foregoing description of specific aspects fully reveals the overall nature of the present disclosure, such that those skilled in the art can readily modify and / or adapt such specific aspects to various uses without undue experimentation and without departing from the overall concept of the present disclosure. Accordingly, such adaptations and modifications are intended to be within the meaning and range of equivalents of the disclosed aspects, based on the teaching and guidance provided herein.

[0106]

[0115] It should be understood that the Detailed Description section, and not the Summary and Abstract sections, is intended to be used to interpret the claims. The Summary and Abstract sections may describe one or more (but not all) aspects of the disclosure as contemplated by the inventors, and therefore are not intended to limit the disclosure and the appended claims. The breadth and scope of protected subject matter should not be limited by any of the above-described aspects, but should be defined only by the following claims and their equivalents.

Claims

1. 1. A lithographic apparatus comprising: an illumination system configured to illuminate a pattern on a patterning device; a projection system configured to project an image of the pattern onto a substrate; a detection system, the detection system comprising: Parallel arranged sensors, Performing an inspection of the targets on the substrate; and moving in a first direction during the inter-test period a sensor configured as follows: a substrate support structure configured to support and move the substrate in a second direction opposite to the first direction while the sensor is moved in the first direction during the period.

2. The apparatus of claim 1 , wherein the sensor and the substrate support structure are configured to move in the first direction and the second direction, respectively, while the sensor is performing the inspection.

3. The apparatus of claim 1 , wherein each sensor is configured to be individually positionable.

4. The apparatus of claim 3 , wherein each sensor includes an actuator configured to adjust each sensor independently of the other sensors.

5. The apparatus of claim 1 , wherein each sensor is configured to have an adjustable rate of movement.

6. The apparatus of claim 1 , wherein the detection system is configured to perform an alignment process based on the inspection.

7. The apparatus of claim 1 , wherein the detection system is configured to perform an overlay error analysis based on the inspection.

8. 10. The apparatus of claim 1, wherein the projection system is configured to move in the first direction during periods between exposures of the substrate with the pattern and while the substrate is moved in a second direction opposite the first direction.

9. 1. A system comprising: Parallel arranged sensors, Performing an inspection of the targets on the substrate; and moving in a first direction during the inter-test period a sensor configured as follows: a substrate support structure configured to support and move the substrate in a second direction opposite the first direction while the sensor is moved in the first direction during the period; A system comprising:

10. 10. The system of claim 9, wherein the sensor and the substrate support structure are configured to move in the first direction and the second direction, respectively, while the sensor performs the inspection of the target on the substrate.

11. The system of claim 9 , wherein each sensor is configured to be individually positionable.

12. The system of claim 11 , wherein each sensor includes an actuator configured to adjust each sensor independently of the other sensors.

13. The system of claim 9 , wherein each sensor is configured to have an adjustable rate of movement.

14. The system of claim 9 , wherein the system is configured to perform an alignment process based on the inspection.

15. The system of claim 9 , wherein the system is configured to perform an overlay error analysis based on the inspection.

Images