Enabling multiple markers in alignment sensors

Abstract

A substrate alignment apparatus is described. The illumination system receives a source radiation beam from the radiation source and directs the source radiation beam toward the pupil plane. An optical component is positioned at the pupil plane to direct component beams of the source radiation beam toward a plurality of alignment marks on the substrate. At least one objective lens module is disposed between the optical component and the substrate and focuses the separation beam on a corresponding separation mark of the plurality of alignment marks. The interferometer receives a diffracted radiation beam diffracted from the plurality of alignment marks, collected by the at least one objective module, and directed to the interferometer by the optical component.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. application 63 / 448,089, filed on February 24, 2023, and the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present disclosure relates to systems, methods, and apparatus for measuring alignment marks, for example, to systems for rapidly measuring multiple alignment marks in lithographic apparatus and systems. Background Art

[0004] A lithographic apparatus is a machine that applies a desired pattern to a substrate, typically to a target portion of the substrate. A lithographic apparatus can be used, for example, in the manufacture of integrated circuits (ICs). In this case, a patterning device, which can be a mask or reticle, can be used to generate the circuit pattern to be formed on the individual layers of the IC. The pattern can be transferred to a target portion (e.g., a portion comprising one or several die) on a substrate (e.g., a silicon wafer). The transfer of the pattern is typically performed by imaging onto a layer of radiation-sensitive material (photoresist or simply "resist") disposed on the substrate. Typically, a single substrate will contain a network of adjacent target portions that are continuously patterned. Known lithographic apparatuses include so-called steppers, in which each target portion is irradiated by exposing the entire pattern to the target portion at once, and so-called scanners, in which each target portion is irradiated by scanning the pattern with a radiation beam in a given direction ("scanning" direction) while simultaneously scanning target portions that are parallel or antiparallel to the scanning direction. A pattern can also be transferred from a patterning device to a substrate by imprinting the pattern onto the substrate.

[0005] During a photolithography operation, different processing steps may require sequential formation of different layers on a substrate. Therefore, it may be necessary to position the substrate relative to a previous pattern formed thereon with high precision. Typically, alignment marks are placed on the substrate to be aligned and positioned with reference to a second object. The photolithography apparatus may employ an alignment device for detecting the position of the alignment marks and for aligning the substrate using the alignment marks to ensure accurate exposure from the mask. Misalignment between alignment marks at two different layers is measured as overlay error.

[0006] To monitor the lithography process, parameters of the patterned substrate are measured. For example, these parameters may include the overlay error between successive layers formed in or on the patterned substrate and the critical linewidth of the developed photoresist. The measurements can be performed on a production substrate and / or on a dedicated metrology target. Various techniques exist for measuring the microstructures formed in the lithography process, including the use of scanning electron microscopes and various specialized tools. A rapid and non-invasive form of specialized inspection tool is a scatterometer, in which a radiation beam is directed onto a target on the substrate surface and the properties of the scattered or reflected beam are measured. 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 with data stored in a library of known measurements associated with known substrate properties. Spectral 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 specific narrow angular range. In contrast, angle-resolved scatterometers use a monochromatic radiation beam and measure the intensity of the scattered radiation as a function of angle.

[0007] Such optical scatterometers can be used to measure parameters such as the critical dimension of a developed photoresist or the overlay error (OV) between two layers formed in or on a patterned substrate. The characteristics of the substrate can be determined by comparing the characteristics of the illumination beam before and after it is reflected or scattered by the substrate.

[0008] Alignment mark measurement by conventional systems is limited to measuring only one alignment mark at a time. This limitation of conventional alignment mark measurement systems imposes severe restrictions on the throughput of lithography apparatuses, which rely on accurate measurement of alignment marks to perform lithography processes on substrates. Summary of the Invention

[0009] Therefore, it is desirable to measure multiple alignment marks at once, thereby increasing lithography throughput.

[0010] In some aspects, a substrate alignment apparatus includes an illumination system configured to receive a source radiation beam from a radiation source and direct the source radiation beam toward a pupil plane. An optical component is positioned at the pupil plane and configured to direct split beams of the source radiation beam toward a plurality of alignment marks on a substrate. At least one objective lens module is positioned between the optical component and the substrate and configured to focus the split beams of the source radiation beam onto corresponding split marks of the plurality of alignment marks. An interferometer is configured to receive the diffracted radiation beam diffracted from the plurality of alignment marks, collected by the at least one objective lens module, and directed to the interferometer by the optical component.

[0011] In some aspects, a lithographic apparatus includes a radiation source configured to generate a radiation beam, a substrate holder configured to support a substrate, and a substrate alignment apparatus. The substrate alignment apparatus includes an illumination system configured to receive a source radiation beam from the radiation source and direct the source radiation beam toward a pupil plane. An optical component is positioned at the pupil plane and is configured to direct split beams of the source radiation beam received from the illumination system toward a plurality of alignment marks on the substrate. At least one objective lens module is disposed between the optical component and the substrate holder and is configured to focus the split beams of the source radiation beam onto corresponding split marks of the plurality of alignment marks. An interferometer is configured to receive a diffracted radiation beam diffracted from the plurality of alignment marks, collected by the at least one objective lens module, and directed to the interferometer by the optical component.

[0012] In some aspects, a method of aligning a substrate includes directing a source radiation beam from a radiation source toward a pupil plane using an illumination system. Using an optical component, split beams of the source radiation beam are directed toward a plurality of alignment marks on a substrate. Using at least one objective lens module positioned between the optical component and the substrate, some of the component beams of the source radiation beam are focused onto corresponding split beams of the plurality of alignment marks. An interferometer receives the diffracted radiation beams diffracted from the plurality of alignment marks, collected by the at least one objective lens module, and directed by the optical component.

[0013] Other features of various aspects of the present disclosure are described in detail below with reference to the accompanying drawings. It is noted that the present disclosure is not limited to the specific aspects described herein. Such aspects are presented herein for illustrative purposes only. Based on the teachings contained herein, additional aspects will be apparent to those skilled in the relevant art. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The accompanying drawings, which are incorporated herein and form a part of the specification, illustrate the disclosure and, together with the description, further serve to explain the principles of the disclosure and to enable one skilled in the relevant art to make and use the aspects described herein.

[0015] Figure 1A A reflective lithography apparatus according to some aspects is shown.

[0016] Figure 1B A transmissive lithography apparatus according to some aspects is shown.

[0017] Figure 2 Shown are further details of a reflective lithography apparatus according to some aspects.

[0018] Figure 3 A lithographic cell according to some aspects is shown.

[0019] Figure 4A and Figure 4B An inspection apparatus according to some aspects is shown.

[0020] Figure 5 A substrate alignment apparatus according to an embodiment is shown.

[0021] Figure 6 A substrate alignment apparatus according to other embodiments is shown.

[0022] Figure 7 A substrate alignment apparatus according to another embodiment is shown.

[0023] The features of the present disclosure will become more apparent from the detailed description set forth below in conjunction with the accompanying drawings, in which like reference numerals identify corresponding elements throughout. In the drawings, like reference numerals generally indicate identical, functionally similar, and / or structurally similar elements. Additionally, the left-most digit of a reference numeral generally identifies the drawing in which the reference numeral first appears. Unless otherwise indicated, the drawings provided throughout this disclosure should not be construed as being drawn to scale. DETAILED DESCRIPTION

[0024] The aspects described herein and references in this specification to "an aspect, an aspect," "exemplary aspect," "example aspect," etc. indicate that the described aspects may include a particular feature, structure, or characteristic, but every aspect may not necessarily include the particular feature, structure, or characteristic. Furthermore, such phrases are not necessarily referring to the same aspect. Furthermore, when a particular feature, structure, or characteristic is described in conjunction with an aspect, it is understood that it is within the common knowledge of those skilled in the art to implement such feature, structure, or characteristic in conjunction with other aspects (whether or not explicitly described).

[0025] For convenience of description, spatially relative terms (such as "below," "beneath," "above," "above," etc.) may be used herein to describe the relationship of one element or feature to other elements or features as illustrated in the figures. 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 device may be otherwise oriented (rotated 90 degrees or at other orientations), and the spatially relative descriptors used herein should be interpreted accordingly.

[0026] The terms "about," "approximately," and the like may be used herein to indicate that a value of a given quantity may vary based on the particular technology. Depending on the particular technology, the terms "about," "approximately," and the like may indicate that a value of a given quantity varies within, for example, 10% to 30% of the value of the given quantity (e.g., ±10%, ±20%, or ±30% of the value).

[0027] 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 that can be read and executed 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; electrical, optical, acoustic, or other forms of propagated signals (e.g., carrier waves, infrared signals, digital signals, etc.), etc. In addition, firmware, software, routines, and / or instructions may be described herein as performing certain actions. However, it should be understood that such descriptions are merely for convenience, and that such actions are obtained by a computing device, processor, controller, or other device that executes the firmware, software, routines, instructions, etc. The term "machine-readable medium" may be interchangeable with similar terms (e.g., "computer program product," "computer-readable medium," "non-transitory computer-readable medium," etc.). The term "non-transitory" may be used herein to characterize one or more forms of computer-readable media other than transient propagated signals.

[0028] However, before describing such aspects in greater detail, it is instructive to present an example environment in which aspects of the present disclosure may be implemented.

[0029] Example lithography system

[0030] Figure 1A and Figure 1B A lithographic apparatus 100 and a lithographic apparatus 100' are shown, respectively, in which aspects of the present disclosure may be implemented. The lithographic apparatus 100 and the 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 stage) MT configured to support a patterning device (e.g., 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 (e.g., a wafer stage) 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. The lithographic apparatuses 100 and 100' also have a projection system PS configured to project a pattern imparted by the patterning device MA to the radiation beam B onto a target portion (e.g., comprising one or more dies) C of the substrate W. In the lithographic apparatus 100, the patterning device MA and the projection system PS are reflective. In the lithographic apparatus 100', the patterning device MA and the projection system PS are transmissive.

[0031] The illumination system IL may include various types of optical components for directing, shaping or controlling the radiation beam B, such as refractive, reflective, catadioptric, magnetic, electromagnetic, electrostatic, or other types of optical components, or any combination thereof.

[0032] The support structure MT holds the patterning device MA in a manner that depends on the orientation of the patterning device MA relative to the reference frame, the design of at least one of the lithographic apparatuses 100 and 100', and other conditions (such as whether 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. For example, the support structure MT can be a frame or a stage, which can be fixed or movable. By using sensors, the support structure MT can ensure that the patterning device MA is in a desired position, for example, relative to the projection system PS.

[0033] The term “patterning apparatus” MA should be broadly interpreted as referring to any apparatus that can be used to impart a radiation beam B with a pattern in its cross-section, such as to form a pattern in a target portion C of a substrate W. The pattern imparted to the radiation beam B may correspond to a particular functional layer to be formed in the target portion C for forming a device used to form an integrated circuit.

[0034] The patterning device MA may be transmissive (e.g. Figure 1B lithographic apparatus 100') or reflective (as in Figure 1A 100). 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. Examples of programmable mirror arrays employ a matrix arrangement of small mirrors, each of which can be individually tilted to reflect an incoming radiation beam in different directions. The tilted mirrors impart a pattern in the radiation beam B, which is reflected by the matrix of small mirrors.

[0035] The term "projection system" PS may encompass any type of projection system (including refractive, reflective, catadioptric, magnetic, electromagnetic, and electrostatic optical systems, or any combination thereof) suitable for the exposure radiation 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 may be used for EUV or electron beam radiation, as other gases may absorb excess radiation or electrons. Therefore, a vacuum environment may be provided to the entire beam path with the aid of vacuum walls and a vacuum pump.

[0036] The lithographic apparatus 100 and / or the lithographic apparatus 100' may be of a type having two (dual stage) or more substrate tables WT (and / or more than two 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 cases, the additional tables may not be substrate tables WT.

[0037] The lithographic apparatus may also be of a type in which at least a portion of the substrate may be covered by a liquid having a relatively high refractive index (e.g., water) so as to fill the space between the projection system and the substrate. Immersion liquid may also be applied to other spaces in the lithographic apparatus, such as between the mask and the projection system. Immersion techniques are well known in the art and are used to increase the numerical aperture of the projection system. As used herein, the term "immersion" does not mean that the structure (such as the substrate) must be submerged in the liquid. For example, during exposure, the liquid may be located between the projection system and the substrate.

[0038] Reference Figure 1A and Figure 1B , the illuminator IL receives a radiation beam from a radiation source SO. For example, when the source SO is an excimer laser, the source SO and the lithographic apparatus 100, 100' may be separate physical entities. In this case, the source SO is not considered to form part of the lithographic apparatus 100 or 100', and the radiation beam B is transmitted to the lithographic apparatus 100 or 100' by the beam delivery system BD (in the embodiment of FIG. Figure 1B The radiation system may comprise a source SO, an illuminator IL, and / or a beam delivery system BD.

[0039] The illuminator IL may comprise an adjuster AD (at Figure 1B Typically, 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 can be adjusted. In addition, the illuminator IL may include various other components (in Figure 1B The illuminator IL may be used to condition the radiation beam B so as to have a desired uniformity and intensity distribution in its cross-section.

[0040] Reference Figure 1A, a radiation beam B is incident on a patterning device (e.g., a mask) MA held on a support structure (e.g., a mask table) MT and is patterned by the patterning device MA. In the lithographic apparatus 100, the radiation beam B is reflected from the patterning device (e.g., a mask) MA. After reflecting from the patterning device (e.g., a mask) MA, the radiation beam B passes through a projection system PS, which focuses the radiation beam B onto a target portion C of a substrate W. With the aid of 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 accurately moved (e.g., in order to position a different target portion C in the path of the radiation beam B). Similarly, a first positioner PM and a further position sensor IF1 can be used to accurately position the patterning device (e.g., a mask) MA relative to the path of the radiation beam B. The patterning device (e.g., a mask) MA and the substrate W can be aligned using mask alignment marks M1, M2 and substrate alignment marks P1, P2.

[0041] Reference Figure 1B , a radiation beam B is incident on a patterning device (e.g., mask MA) held on a support structure (e.g., mask table MT) and is patterned by the patterning device. After passing through 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 conjugate PPU to the illumination system pupil IPU. Some portion of the radiation originates from the intensity distribution at the illumination system pupil IPU and passes through the mask pattern without being affected by diffraction at the mask pattern, and forms an image of the intensity distribution at the illumination system pupil IPU.

[0042] The projection system PS projects an image of a mask pattern MP onto a photoresist layer coated on a substrate W, wherein the image is formed by a diffraction beam generated from the mask pattern MP by radiation from an intensity distribution. For example, the mask pattern MP may comprise an array of lines and spaces. The diffraction of radiation at the array, which is different from the zero-order diffraction, generates a steering diffraction beam having a change in direction in a direction perpendicular to the lines. The undiffracted beam (i.e. the so-called zero-order diffraction beam) penetrates the pattern without any change in the propagation direction. The zero-order diffraction beam penetrates an upper lens or an upper lens group of the projection system PS upstream of a pupil conjugate PPU of the projection system PS to reach the pupil conjugate PPU. The part of the intensity distribution in the plane of the pupil conjugate PPU and associated with the zero-order diffraction 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 placed or substantially placed at a plane including the pupil conjugate PPU of the projection system PS.

[0043] The projection system PS is arranged to capture (e.g., using a lens or lens group L) a zero-order diffraction beam, a first-order diffraction beam, and / or higher-order diffraction beams (not shown). In some aspects, dipole illumination for imaging a line pattern extending in a direction perpendicular to the line can be used to exploit the resolution enhancement effect of dipole illumination. For example, the first-order diffraction beam interferes with the corresponding zero-order diffraction beam at the level of the wafer W to form an image of the line pattern MP with the highest possible resolution and process window (i.e., usable depth of focus combined with tolerable exposure dose deviation). In some aspects, astigmatic aberrations can be reduced by providing radiation poles (not shown) in opposite quadrants of the illumination system pupil IPU. Additionally, in some aspects, astigmatic aberrations can be reduced by blocking the zero-order beam associated with the radiation pole in the opposite quadrant in the pupil conjugate PPU of the projection system. This is described in more detail in US 7,511,799 B2, issued on March 31, 2009, the entire contents of which are incorporated herein by reference in their entirety.

[0044] With the aid of a 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 a different target portion C in the path of the radiation beam B). Similarly, the first positioner PM and another position sensor ( Figure 1B ) can be used to accurately position the mask MA relative to the path of the radiation beam B (eg after mechanical retrieval from a mask library or during scanning).

[0045] Typically, movement of the mask table MT can be achieved 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. Similarly, movement of the substrate table WT can be achieved using a long-stroke module and a short-stroke module which form part of the second positioner PW. In the case of a stepper (in contrast to a scanner), the mask table MT may be connected to a short-stroke actuator or may be fixed. Mask alignment marks M1, M2 and substrate alignment marks P1, P2 may be used to align the mask MA and the substrate W. Although the substrate alignment marks (as shown) occupy dedicated target portions, they may be located in the space between the target portions (called scribe alignment marks). Similarly, in the case where more than one die is provided on the mask MA, the mask alignment marks may be located between the dies.

[0046] The 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 the patterning device (such as a mask) into and out of the vacuum chamber. Alternatively, when the mask table MT and patterning device MA are outside the vacuum chamber, an out-of-vacuum robot can be used for various transport operations, similar to the in-vacuum robot IVR. Both the in-vacuum robot and the out-of-vacuum robot can be calibrated to smoothly transfer any payload (e.g., a mask) to the fixed kinematic support of the transfer station.

[0047] The lithographic apparatuses 100 and 100' may be used in at least one of the following modes:

[0048] 1. In step mode, the support structure (e.g. mask table) MT and substrate table WT are held substantially stationary while an entire pattern imparted to the radiation beam B is projected at once onto a target portion C (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.

[0049] 2. In scan mode, the support structure (e.g. mask table) MT and substrate table WT are scanned synchronously while a pattern imparted to the radiation beam B is projected onto a target portion C (i.e. single dynamic exposure). The speed 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.

[0050] 3. In another mode, the support structure (e.g., mask table) MT remains essentially stationary, thereby holding the 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 required after each movement of the substrate table WT or between successive radiation pulses during a scan. This mode of operation can be readily applied to maskless lithography utilizing a programmable patterning device, such as a programmable mirror array.

[0051] Combinations and / or variations of the described modes of use or entirely different modes of use may also be employed.

[0052] In some aspects, the lithographic apparatus 100 includes an extreme ultraviolet (EUV) source configured to generate an EUV radiation beam for EUV lithography. Typically, 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.

[0053] In some aspects, the lithographic apparatus 100' includes a deep ultraviolet (DUV) source configured to generate a DUV radiation beam for DUV lithography. Typically, 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.

[0054] Figure 2 The lithographic apparatus 100 is shown in greater detail and includes a source collector arrangement SO, an illumination system IL, and a projection system PS. The source collector arrangement SO is constructed and arranged so that a vacuum environment can be maintained within an enclosure 220 of the source collector arrangement SO. A plasma 210 emitting EUV radiation can be formed by a discharge-generated plasma source. In some aspects, a plasma of tin (Sn) that is excited (e.g., via laser excitation) is provided to generate EUV radiation.

[0055] The radiation emitted by the EUV radiation-emitting plasma 210 is transferred from the source chamber 211 to the collector chamber 212 via an optional gas barrier or contamination trap 230 (also referred to as a contamination barrier or fin trap in some cases), which is positioned in or behind an opening in the source chamber 211. The contamination trap 230 may include a channel structure. The contamination trap 230 may also include a gas barrier or a combination of a gas barrier and a channel structure. The contamination trap or contamination barrier 230 further indicated herein includes at least a channel structure.

[0056] 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 penetrating the collector CO may be reflected from the grating spectral filter 240 to be focused in a virtual source point INTF. The virtual source point INTF is often referred to as an intermediate focus, and the source collector arrangement 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 plasma 210 emitting EUV radiation. The grating spectral filter 240 is particularly useful for suppressing infrared (IR) radiation.

[0057] The radiation then passes through an illumination system IL, which may include a faceted field mirror device 222 and a faceted pupil mirror device 224, which are arranged to provide a desired angular distribution of the radiation beam 221 at the patterning device MA, and a desired uniformity of radiation intensity at the patterning device MA. When the radiation beam 221 is reflected at the patterning device MA, which is held by the support structure MT, a patterned beam 226 is formed, and the patterned beam 226 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.

[0058] In general, there may be more elements in the illumination optics unit IL and the projection system PS than shown. Depending on the type of lithographic apparatus, a grating spectral filter 240 may optionally be present. In addition, there may be more than Figure 2 The mirrors shown are further mirrors, for example, in the projection system PS, with Figure 2 There may be one to six additional reflective elements than shown in .

[0059] like Figure 2 As illustrated, the collector optics CO is depicted as a nested collector with grazing incidence reflectors 253, 254 and 255, which is merely an example of a collector (or collector mirror). The grazing incidence reflectors 253, 254 and 255 are positioned axisymmetrically around the optical axis O, and this type of collector optics CO is preferably used in combination with a discharge generated plasma source (commonly referred to as a DPP source).

[0060] Example Lithography Cell

[0061] Figure 3 A lithography unit 300 is shown, which is sometimes also referred to as a lithocell or cluster, according to some aspects. The lithography apparatus 100 or 100' may form part of the lithography unit 300. The lithography unit 300 may also include one or more devices for performing pre-exposure and post-exposure processes on the substrate. Conventionally, these include a spin coater SC for depositing a resist layer, a developer DE for developing the exposed resist, a cooling plate CH, and a baking plate BK. A substrate handler or robot RO picks up substrates from input / output ports I / O1, I / O2, moves them between the different process devices, and delivers them to a feed station LB of the lithography apparatus 100 or 100'. These devices, also commonly referred to as tracks, are under the control of a track control unit TCU, which itself may be controlled by a supervisory control system SCS, which also controls the lithography apparatus via a lithography control unit LACU. Thus, different devices may be operated to maximize throughput and processing efficiency.

[0062] Example inspection device

[0063] In order to control the lithography process so that the device features are accurately placed on the substrate, alignment marks are usually provided on the substrate, and the lithography apparatus includes one or more inspection devices for accurately positioning 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. One type of system widely used in current lithography apparatuses is based on a self-referencing interferometer as described in U.S. Patent No. 6,961,116 (den Boef et al.). Typically, the marks are measured separately to obtain the X position and the Y position. However, a combined X measurement and Y measurement can be performed using the techniques described in U.S. Publication No. 2009 / 195768A (Bijnen et al.). The entire contents of both publications are incorporated herein by reference.

[0064] Figure 4A A cross-sectional view of an inspection apparatus 400, which can be implemented as part of a lithographic apparatus 100 or 100', according to some aspects, is shown. In some aspects, the inspection apparatus 400 can be configured to align a substrate (e.g., substrate W) relative to a patterning device (e.g., patterning device MA). The inspection apparatus 400 can be further configured to detect the positions of alignment marks on the substrate and use the detected alignment mark positions to align the substrate relative to the patterning device or other components of the lithographic apparatus 100 or 100'. This alignment of the substrate can ensure accurate exposure of one or more patterns on the substrate.

[0065] The terms "inspection device", "measurement system", etc. may be used in this document to refer to, for example, equipment for measuring the characteristics of a structure (e.g., overlay accuracy sensor, critical dimension sensor, etc.), equipment or systems for checking the alignment of a chip in a lithography device (e.g., alignment sensor), etc.

[0066] In some aspects, 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 accuracy calculation processor 432. Illumination system 412 may be configured to provide an electromagnetic narrowband radiation beam 413 having one or more passbands. In an example, the one or more passbands may be within a spectrum of wavelengths between approximately 500 nm and approximately 900 nm. In another example, the one or more passbands may be discrete narrow passbands within a spectrum of wavelengths between approximately 500 nm and approximately 900 nm. Illumination system 412 may further be configured to provide one or more passbands having a substantially constant center wavelength (CWL) value over a long period of time (e.g., over the lifetime of illumination system 412). In current alignment systems, as discussed above, this configuration of illumination system 412 may help prevent actual CWL values ​​from drifting from desired CWL values. Consequently, the use of a constant CWL value may improve the long-term stability and accuracy of an alignment system (e.g., inspection apparatus 400) compared to current alignment apparatuses.

[0067] In some aspects, beam splitter 414 can be configured to receive radiation beam 413 and split radiation beam 413 into at least two radiation sub-beams. For example, radiation beam 413 can be split into radiation sub-beams 415 and 417, as shown in FIG. Figure 4AAs shown. The beam splitter 414 can be further configured to direct the radiation sub-beam 415 onto a substrate 420 placed on a stage 422. In one example, the stage 422 is movable along a direction 424. The radiation sub-beam 415 can be configured to illuminate an alignment mark or target 418 located on the substrate 420. The alignment mark or target 418 can be coated with a radiation-sensitive film. In some aspects, the alignment mark or target 418 can have a one hundred and eighty degree (i.e., 180°) symmetry. That is, when 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 can be substantially identical to the unrotated alignment mark or target 418. The target 418 on the substrate 420 can be (a) a resist layer grating comprising strips formed from solid resist lines, or (b) a product layer grating, or (c) a composite grating stack in an overlay target structure comprising a resist grating overlying or interleaved on the product layer grating. Alternatively, the strips can be etched into the substrate. The pattern is sensitive to chromatic aberrations in the lithographic projection apparatus (particularly the projection system PL), and the illumination symmetry and the presence of such aberrations will manifest themselves in variations in the printed grating. One in-line method for measuring line width, spacing, and critical dimensions in device fabrication 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 in 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 reflection spectrum at a given angle is detected. The structure causing the reflection spectrum is reconstructed, for example, using rigorous coupled wave analysis (RCWA) or by comparison with a library of patterns derived by simulation. Thus, the scatterometry data of the printed grating are used to reconstruct the grating. The parameters of the grating, such as line width and shape, can be input to the reconstruction process performed by the processing unit PU based on knowledge of the printing step and / or other scatterometry processes.

[0068] In some aspects, according to one aspect, beam splitter 414 can be further configured to receive diffracted radiation beam 419 and split diffracted radiation beam 419 into at least two radiation sub-beams. Diffracted radiation beam 419 can be split into diffracted radiation sub-beams 429 and 439, as shown in FIG. Figure 4A shown.

[0069] It should be noted that even though beam splitter 414 is shown as directing radiation sub-beam 415 toward alignment mark or target 418 and directing diffracted radiation sub-beam 429 toward interferometer 426, the present disclosure is not limited thereto. Other optical arrangements may be used to achieve similar results of illuminating alignment mark or target 418 on substrate 420 and detecting an image of alignment mark or target 418.

[0070] like Figure 4A As illustrated, the interferometer 426 can be configured to receive the radiation sub-beam 417 and the diffracted radiation sub-beam 429 via the beam splitter 414. In an example aspect, the diffracted radiation sub-beam 429 can be at least a portion of the radiation sub-beam 415 that can be reflected from the alignment mark or target 418. In an example of this aspect, the interferometer 426 includes any suitable set of optical elements (e.g., a combination of prisms) that can be configured to form two images of the 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. Resolving features of the alignment mark 418 may be sufficient. The interferometer 426 can be further configured to rotate one of the two images 180° relative to the other of the two images and interferometrically recombine the rotated image with the unrotated image.

[0071] In some aspects, the detector 428 can be configured to receive the recombined image via the interferometer signal 427 and detect interference due to the recombined image when the alignment axis 421 of the inspection device 400 passes through the center of symmetry (not shown) of the alignment mark or target 418. According to example aspects, this interference can be due to the alignment mark or target 418 being 180° symmetrical and the recombined images interfering constructively or destructively. Based on the detected interference, the detector 428 can be further configured to determine the position of the center of symmetry of the alignment mark or target 418 and, therefore, detect the position of the substrate 420. According to an example, the alignment axis 421 can be aligned with a light beam that is perpendicular to the substrate 420 and passes through the center of the image rotation interferometer 426. The detector 428 can be further configured to estimate the position of the alignment mark or target 418 by implementing sensor characteristics and interacting with wafer marking process variations.

[0072] In other aspects, 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:

[0073] 1. Measure the positional shift of various wavelengths (positional shift between colors);

[0074] 2. Measure the positional variation of the various orders (positional shifts between diffraction orders); and

[0075] 3. Measure the positional changes of the various polarizations (positional shifts between polarizations).

[0076] 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, which uses a self-referencing interferometer with a single detector and four different wavelengths, and extracts the alignment signal in software, or an Athena (Advanced Technology with High-Order Alignment Enhancement) sensor as described in U.S. Patent 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.

[0077] In some aspects, beam analyzer 430 can be configured to receive and determine the optical state of diffracted radiation sub-beam 439. The optical state can be a measure of the beam wavelength, polarization, or beam profile. Beam analyzer 430 can further be configured to determine the position of stage 422 and relate the position of stage 422 to the position of the center of symmetry of alignment mark or target 418. In this way, the position of alignment mark or target 418 with reference to stage 422 and, therefore, the position of substrate 420 can be accurately known. Alternatively, beam analyzer 430 can be configured to determine the position of inspection device 400 or any other reference element so that the center of symmetry of alignment mark or target 418 with reference to inspection device 400 or any other reference element can be known. Beam analyzer 430 can be a point or imaging polarimeter with some form of wavelength band selectivity. In some aspects, according to other aspects, beam analyzer 430 can be directly integrated into inspection device 400 or connected via several types of optical fibers: polarization-maintaining single mode, multimode, or imaging.

[0078] In some aspects, beam analyzer 430 may be further configured to determine overlay accuracy data between two patterns on substrate 420. One of these patterns may be a reference pattern on a reference layer. The other pattern may be an exposed pattern on an exposure layer. The reference layer may be an etch layer already present on substrate 420. The reference layer may be generated by exposing a reference pattern on the substrate by lithography 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 exposing an exposure pattern on substrate 420 by lithography apparatus 100 or 100'. The exposure pattern on substrate 420 may correspond to movement of substrate 420 under the action of stage 422. In some aspects, the measured overlay accuracy data may also indicate an offset between the reference pattern and the exposure pattern. The measured overlay accuracy data may be used as calibration data for calibrating the exposure pattern exposed by lithography apparatus 100 or 100', such that, after calibration, the offset between the exposure layer and the reference layer can be minimized.

[0079] In some aspects, the beam analyzer 430 can be further configured to determine a model of the product stack profile of the substrate 420 and can be configured to measure the overlay accuracy, critical dimensions, and focus of the target 418 in a single measurement. The product stack profile contains information about the stacked product (such as alignment marks, the target 418, or the substrate 420) and can include optical signature metrics caused by mark processing variations based on illumination variations. The product stack profile can also include product grating profiles, mark stack profiles, and mark asymmetry information. An example of a beam analyzer 430 is the Yieldstar manufactured by ASML of Veldhoven, The Netherlands, as described in U.S. Patent No. 8,706,442. TM , which is incorporated herein by reference in its entirety. The beam analyzer 430 can further be configured to process information related to specific characteristics of the exposure pattern in the layer. For example, the beam analyzer 430 can process overlay accuracy parameters (an indication of the accuracy of positioning of the 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 are image parameters related to the quality of the depicted image of the exposure pattern.

[0080] In some aspects, a detector array (not shown) can be connected to the beam analyzer 430 and allow the possibility of accurate stack profile detection as discussed below. For example, the detector 428 can be a detector array. For the detector array, multiple options are possible: a multimode fiber bundle, a discrete PIN detector for each channel, or a CCD or CMOS (linear) array. The use of a multimode fiber bundle enables any dissipative elements to be remotely located for stability reasons. Discrete PIN detectors provide a large dynamic range, but each detector requires a separate preamplifier. Therefore, the number of elements is limited. CCD linear arrays provide many elements that can be read out at high speed and are particularly interesting if phase-stepped detection is used.

[0081] In some aspects, the second beam analyzer 430' can be configured to receive and determine the optical state of the diffracted radiation sub-beam 429, such as Figure 4B As shown. The optical state can be a measure of the beam wavelength, polarization, or beam profile. The second beam analyzer 430' can be identical to the beam analyzer 430. Alternatively, the second beam analyzer 430' can be configured to perform one or more of the 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. In this way, the position of the alignment mark or target 418 with reference to the stage 422 and, therefore, the position of the substrate 420 can be accurately known. The second beam analyzer 430' can also be configured to determine the position of the inspection device 400 or any other reference element, so that the center of symmetry of the alignment mark or target 418 with reference to the inspection device 400 or any other reference element can be known. The second beam analyzer 430' can further be configured to determine overlay accuracy data between the two patterns and a model of the product stacking profile of the substrate 420. The second beam analyzer 430' can further be configured to measure the overlay accuracy, critical dimension, and focus of the target 418 in a single measurement.

[0082] In some aspects, according to other aspects, second beam analyzer 430' can be integrated directly into inspection apparatus 400, or it can be connected via several types of optical fibers: polarization-maintaining single-mode, multimode, or imaging. Alternatively, second optical analyzer 430' and beam analyzer 430' can be combined to form a single analyzer (not shown) that is configured to receive and determine the optical state of both diffracted radiation sub-beams 429 and 439.

[0083] In some aspects, processor 432 receives information from detector 428 and beam analyzer 430. For example, processor 432 may be an overlay accuracy calculation processor. This information may include a model of the product stack profile constructed by beam analyzer 430. Alternatively, processor 432 may use information received about product markings to construct a model of the product marking profile. In either case, processor 432 uses or incorporates the model of the product marking profile to construct a model of the stacked product and overlay accuracy marking profile. This stack model is then used to determine overlay accuracy offset and minimize spectral effects on the overlay accuracy offset measurement. Processor 432 may create a basic correction algorithm based on information received from detector 428 and beam analyzer 430, including but not limited to the optical state of the illumination beam, alignment signals, associated position estimates, and optical states in pupil, image, and additional planes. The pupil plane is a plane in which the radial position of the radiation defines the angle of incidence and the angular position defines the azimuth angle of the radiation. Processor 432 may utilize this basic correction algorithm to characterize inspection apparatus 400 with reference to wafer marks and / or alignment marks 418.

[0084] In some aspects, the processor 432 can be further configured to determine the print 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 includes, but is not limited to, the product stack profile, the measured value of the overlay accuracy, the critical dimension, and the focus of each alignment mark or target 418 on the substrate 420. The processor 432 can use a clustering algorithm to group the marks into sets of similar constant offset errors and create an alignment error offset correction table based on this information. The clustering algorithm can be based on the overlay accuracy measurements, the position estimates, and additional optical stack processing information associated with each offset error set. Overlay accuracy is calculated for multiple different marks (e.g., at overlay accuracy targets with positive and negative offsets around the programmed overlay accuracy). The target with the minimum measured overlay accuracy is used as a reference (because it is measured with the best accuracy). Based on this measured small overlay accuracy and the known programmed overlay accuracy of its corresponding target, the overlay error can be inferred. Table 1 illustrates how this operation can be performed. In the example shown, the minimum measured overlay accuracy is -1 nm. However, this is relative to the goal of having a programmed overlay of -30nm. The process may introduce an overlay error of 29nm.

[0085]

[0086] The minimum value can be taken as a reference point, and relative to this, the offset between the measured overlay accuracy and the overlay accuracy expected due to the programmed overlay accuracy can be calculated. This offset determines the overlay accuracy error of each mark or a set of marks with similar offsets. Therefore, in the example of Table 1, at the target position, the minimum measured overlay accuracy is -1nm and the programmed overlay accuracy is 30nm. The difference between the expected overlay accuracy and the measured overlay accuracy at other targets is compared with this reference. A table (such as Table 1) can also be obtained from the mark and target 418 under different illumination settings, and the illumination setting and its corresponding calibration factor that obtain the minimum overlay accuracy error can be determined and selected. After this, the processor 432 can group the marks into a set of similar overlay accuracy errors. The criteria for the mark grouping can be adjusted based on different process controls (e.g., different error tolerances for different processes).

[0087] In some aspects, the processor 432 can determine that all or most members of the group have similar offset errors and apply individual offset corrections from the clustering algorithm to each mark based on its additional optical stack metric. The processor 432 can determine the correction for each mark and feed the correction back to the lithographic apparatus 100 or 100' to correct for errors in overlay accuracy, for example, by feeding the correction into the inspection apparatus 400.

[0088] Exemplary substrate alignment apparatus

[0089] Figure 5 1 , a substrate alignment device 500 is shown in accordance with some embodiments. The substrate alignment device 500 includes a beam splitter 501, an interferometer 502, an optical component 504, and an objective lens module 506. The beam splitter 501 receives a source radiation beam 510 from a radiation source via, for example, an illumination system IL as described above, and directs the source radiation beam 510 toward a pupil plane. The optical component 504 is located in the pupil plane of the objective lens 506. The optical component 504 is configured to redirect the source radiation beam 510 into a plurality of beams 511a, 511b, and 511c (collectively referred to as beams 511). The beams 511 are then directed through the objective lens module 506 to corresponding alignment marks in the alignment marks 509 placed on the substrate 508. The beam diffracted by the alignment marks 509a, 509b, 509c is collimated by the objective lens module 506 and directed to the optical component 504, which is configured to redirect the diffracted beam towards the interferometer 502 to generate an alignment signal.

[0090] Figure 5Show that optical component 504 is configured to redirect source radiation beam 510 into three beams: 511a, 511b and 511c, but this configuration is just shown for the purpose of illustration.The present invention is not limited to three beams, but contains and uses any number of beams, comprises and only uses two beams, uses three beams or uses more than three beams.In a non-restrictive aspect, optical component 504 is configured to redirect source radiation beam 510 into four beams.In practice, source radiation beam 510 can be redirected into n beams, and wherein n represents any integer.For example, the limitation of n may come from the spatial consideration of objective lens module 506, from the maximum desired number of alignment mark 509 on substrate 508 or from other actual considerations.

[0091] Preferably, interferometer 502 is a self-referencing interferometer (SRI). In some embodiments, interferometer 502 is a single SRI. In some aspects, interferometer 502 can receive radiation from a radiation source and transmit the radiation to optical component 504 (as well as objective module 506 and substrate 508). In some aspects, interferometer 502 can also receive radiation diffracted from substrate 508 (via objective module 506 and optical component 504). In some aspects, radiation diffracted from multiple alignment marks can constitute a diffracted radiation beam. Such a diffracted radiation beam can be collected by objective module 506 to be incident on optical component 504, which can then direct the diffracted radiation beam toward interferometer 502. That is, source radiation beam 510 and component beams 511 can include radiation that is both on its way to substrate 508 and incident on alignment mark 509, and that has been diffracted from substrate 508 by alignment mark 509. In some embodiments where interferometer 502 includes an SRI, radiation from optical component 504 may have a different phase than radiation to optical component 504, which may be measured by the SRI.

[0092] In some aspects, the optical component 504 may include a scanning galvanometer. The scanning galvanometer may have one or more degrees of freedom. For example, Figure 5 As shown, the optical component 504 can be a galvanometer having a certain degree of freedom, which is the angle formed between the normal vector at the surface of the scanning galvanometer and the normal vector at the surface of the substrate 508. The scanning galvanometer can be rotated along an axis to increase and / or decrease the angle. In some aspects, rapid rotation of the scanning galvanometer along the axis can redirect the source radiation beam 510 into multiple beams 511, each beam 511 is directed toward a different portion of the objective lens module 506. The scanning galvanometer can also operate with other degrees of freedom to spatially separate the beams 511 in both the x-direction and the y-direction, for example.

[0093] In some aspects, the objective lens module 506 can include a large field of view telecentric objective lens module. In some aspects, the large field of view telecentric objective lens module can have a numerical aperture of 0.6 and a field of view of at least 5 mm. The large field of view telecentric objective lens can be configured to have a wavelength range of 500 nm to 900 nm (including end values). The objective lens module 506 can image an area of ​​approximately 10 mm × 10 mm on the substrate 508, and can also be configured to image a larger area or a smaller area as desired. The objective lens module 506 can be configured to focus each component beam 511 onto the corresponding alignment mark in the alignment mark 509, as described above.

[0094] The substrate 508 may be a substrate on which a fabrication process is to be performed or a substrate on which a fabrication process has been performed. In some aspects, the substrate 508 may be a semiconductor wafer, but the invention is not limited to semiconductor wafers and it is contemplated that many different substrates may be used.

[0095] In some embodiments, source radiation beam 510 may include radiation from a monochromatic light source. However, source radiation beam 510 may also include radiation from a light source that generates radiation having multiple wavelengths. In some embodiments, source radiation beam 510 may be white light. In either case, the scanning galvanometer redirects source radiation beam 510 into beam 511 by separating the beam spatially and / or temporally.

[0096] Figure 6 Another substrate alignment apparatus 600 according to some embodiments is illustrated. The substrate alignment apparatus 600 includes a beam splitter 601, an interferometer 602, an optical component 604, an objective lens module 606, and a substrate 608, each of which functions similarly to the above with respect to Figure 5 In some embodiments, the optical component 604 includes a grating instead of a scanning mirror. The grating can redirect the source radiation beam 610 into a plurality of beams 611.

[0097] In some aspects, the source radiation beam 610 can include radiation having multiple wavelengths. Upon passing through the grating, the source radiation beam 610 can be separated into different beams 611a, 611b, 611c (collectively, beams 611) by optical diffraction of the radiation through the grating. In some aspects, if the source radiation beam 610 includes white light, the beams 611 can constitute, for example, a blue beam, a green beam, and a red beam. Of course, one of ordinary skill in the art will understand that the color of the resulting beam will depend on a variety of factors, including but not limited to the wavelength provided in the source radiation beam 610, the characteristics of the grating, etc. According to some embodiments, each beam 611 can correspond to radiation of a corresponding wavelength in the source radiation beam 610.

[0098] The grating in the optical component 604 can be any pattern that satisfactorily separates the source radiation beam 610 into beams 611. For example, the grating can be a complex two-dimensional structure or a hologram. Alternatively, the grating can be a micro-electromechanical system (MEMS) mirror or an acousto-optic tunable filter (AOTF).

[0099] In some embodiments, source radiation beam 610 can include radiation from a light source that generates radiation having multiple wavelengths. In some embodiments, source radiation beam 610 can be white light. In some aspects, a grating redirects source radiation beam 610 into beam 611 by distinguishing between light of different wavelengths.

[0100] Figure 7 Another substrate alignment apparatus 700 according to some embodiments is illustrated. The substrate alignment apparatus 700 includes a beam splitter 701, an interferometer 702, an optical component 704, an objective lens module 706, and a substrate 708, each of which functions similarly to the above with respect to Figure 5 709a, 709b, 709c (collectively referred to as alignment marks 709). Each objective lens 706 can be placed in the position of the corresponding beam received in beam 711a, 711b, 711c (collectively referred to as beam 711). Alternatively, one or more objective lenses 706 can be positioned to receive more than one beam 711a, 711b, 711c, and each beam 711a, 711b, 711c is guided to the corresponding alignment mark in alignment marks 709. Those skilled in the art will appreciate that objective lenses 706a to 706c can be easily combined with other embodiments of the present invention.

[0101] The following terms may be used to further describe the embodiments:

[0102] 1. A substrate alignment device, comprising:

[0103] an illumination system configured to receive a source radiation beam from a radiation source and direct the source radiation beam toward the pupil plane;

[0104] an optical component positioned at the pupil plane and configured to direct the split beams of the source radiation beam toward the plurality of alignment marks on the substrate;

[0105] at least one objective lens module disposed between the optical component and the substrate and configured to focus the separated beams of the source radiation beam onto corresponding separated marks in the plurality of alignment marks; and

[0106] An interferometer is configured to receive a diffracted radiation beam diffracted from the plurality of alignment marks, collected by the at least one objective lens module, and directed to the interferometer by the optical component.

[0107] 2. The substrate alignment apparatus of clause 1, wherein the interferometer is a self-referencing interferometer.

[0108] 3. The substrate alignment apparatus according to clause 2, wherein the optical component is a scanning galvanometer mirror having at least one degree of freedom.

[0109] 4. The substrate alignment apparatus according to clause 3, wherein the at least one objective lens module is a large field of view telecentric objective lens module.

[0110] 5. The substrate alignment apparatus according to clause 4, wherein the large field of view telecentric objective lens module has a numerical aperture of at least 0.6.

[0111] 6. The substrate alignment apparatus of clause 4, wherein the large field of view telecentric objective lens module has a field of view of at least 5 mm.

[0112] 7. The substrate alignment apparatus according to clause 4, wherein the large field-of-view telecentric objective lens module has a wavelength range greater than or equal to 500 nm and less than or equal to 900 nm.

[0113] 8. The substrate alignment apparatus according to clause 1, wherein the at least one objective lens module comprises a plurality of objective lenses placed at different positions above the substrate.

[0114] 9. The substrate alignment apparatus of clause 8, wherein the optical component is a scanning galvanometer mirror having at least one degree of freedom to direct the split beam and the diffracted radiation beam of the source radiation beam.

[0115] 10. The substrate alignment apparatus according to clause 9, wherein the at least one degree of freedom of the scanning mirror is an angle formed between a normal vector at a surface of the scanning mirror and a normal vector at a surface of the substrate.

[0116] 11. A substrate alignment apparatus according to clause 9, wherein each objective lens is positioned to focus one of the split beams of the source radiation beam and to collect at least one of the diffracted radiation beams.

[0117] 12. The substrate alignment apparatus according to clause 9, wherein the scanning mirror has two degrees of freedom.

[0118] 13. The substrate alignment apparatus of clause 1, wherein the radiation source generates monochromatic radiation.

[0119] 14. The substrate alignment apparatus of clause 1, wherein the radiation source generates radiation having a plurality of wavelengths.

[0120] 15. The substrate alignment apparatus according to clause 1, wherein the optical component is a grating.

[0121] 16. The substrate alignment apparatus according to clause 15, wherein the grating is a complex two-dimensional structure or a hologram.

[0122] 17. The substrate alignment apparatus of clause 15, wherein the grating is a micro-electromechanical system (MEMS) mirror or an acousto-optic tunable filter (AOTF).

[0123] 18. The substrate alignment apparatus of clause 1, wherein:

[0124] The optical component is configured to separate the optical axis at the pupil plane into a plurality of axes; and

[0125] Each axis of the plurality of axes corresponds to a respective wavelength of the source radiation beam from the radiation source.

[0126] 19. A lithographic apparatus comprising:

[0127] a radiation source configured to generate a source radiation beam;

[0128] a substrate holder configured to support a substrate; and

[0129] A substrate alignment device comprising:

[0130] an illumination system configured to receive a source radiation beam from a radiation source and direct the source radiation beam toward the pupil plane;

[0131] an optical component positioned at the pupil plane and configured to direct split beams of the source radiation beam received from the illumination system toward the plurality of alignment marks on the substrate;

[0132] at least one objective lens module positioned between the optical component and the substrate holder and configured to focus separated beams of the source radiation beam on corresponding separated marks of the plurality of alignment marks; and

[0133] An interferometer is configured to receive a diffracted radiation beam diffracted from the plurality of alignment marks, collected by the at least one objective lens module, and directed to the interferometer by the optical component.

[0134] 20. A method of aligning a substrate, comprising:

[0135] directing a source radiation beam from a radiation source toward a pupil plane using an illumination system;

[0136] directing the split beams of the source radiation beam toward a plurality of alignment marks on the substrate using an optical component;

[0137] focusing some of the split beams of the source radiation beam onto corresponding split marks in the plurality of alignment marks using at least one objective lens module positioned between the optical component and the substrate; and

[0138] A diffracted radiation beam diffracted from the plurality of alignment marks is received by an interferometer, collected by the at least one objective lens module, and directed by the optical component.

[0139] Through the above or other embodiments of the present invention, multiple alignment marks can be measured. For example, by redirecting the source radiation beam into separate beams according to the present invention and using other techniques known to those skilled in the art (including but not limited to signal multiplexing, rapid scanning, etc.), hundreds of alignment marks can be measured in a very limited time.

[0140] The terms "radiation," "beam," "light," "irradiation," and the like may be used herein to refer to one or more types of electromagnetic radiation, for example, visible radiation, ultraviolet (UV) radiation (e.g., having a wavelength λ of 365 nm, 248 nm, 193 nm, 157 nm, or 126 nm), extreme ultraviolet (EUV or soft X-ray) radiation (e.g., having a wavelength in the range of 5 nm to 100 nm, such as, for example, 13.5 nm), or hard X-rays operating at less than 5 nm, and particle beams, such as ion beams or electron beams. Generally, radiation having a wavelength between about 400 nm and about 700 nm is considered visible radiation, and radiation having a wavelength between about 780 nm and 3000 nm (or greater) is considered IR radiation. UV refers to radiation having a wavelength of approximately 100 nm to 400 nm. Within lithography, the term "UV" also applies to wavelengths that can be generated 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 nm to 200 nm. Deep UV (DU) generally refers to radiation having a wavelength in the range of 126 nm to 428 nm, and in some aspects, an excimer laser can generate DUV radiation for use within a lithographic apparatus. It should be understood that radiation having a wavelength in the range of, for example, 5 nm to 20 nm refers to radiation having a wavelength band, at least a portion of which is within the range of 5 nm to 20 nm.

[0141] Although some aspects of the present disclosure are described in the context of a lithography apparatus for manufacturing ICs, it will be understood that the lithography apparatus described herein may be used in other applications, for example, for manufacturing integrated optical systems, guidance and detection patterns for magnetic domain memories, flat panel displays, LCDs, thin film heads, etc. Those skilled in the art will understand that in the context of such alternative applications, any use of the terms "wafer" or "die" herein may be considered as specific examples of the more general terms "substrate" or "target portion", respectively. The substrate may be processed before or after exposure in, for example, a tracking 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, the various aspects disclosed herein may be applied to such and other substrate processing tools. In addition, a substrate may be processed more than once, for example to form a multi-layer IC, so that the term substrate as used herein may also refer to a substrate that already contains multiple processed layers.

[0142] Furthermore, while some aspects of the present disclosure are described in the context of optical lithography, it should be understood that aspects of the present disclosure are not limited to optical lithography. For example, in imprint lithography, the topography in the patterning device defines the pattern formed on the substrate. The topography of the patterning device can be pressed into a layer of resist supplied to the substrate, and the resist is then cured by applying electromagnetic radiation, heat, pressure, or a combination thereof. The patterning device is removed from the resist, leaving a pattern in the resist after it cures.

[0143] It should be understood that the phraseology or terminology herein is for the purpose of description rather than limitation, so that the phraseology or terminology of this specification will be interpreted by those skilled in the relevant art in accordance with the teachings herein.

[0144] The present disclosure has been described above with the aid of functional building blocks that illustrate the implementation of specified functions and their relationships. For ease of description, the boundaries of these functional building blocks have been arbitrarily defined herein. Alternative boundaries may be defined so long as the specified functions and their relationships are appropriately performed. The foregoing description of specific aspects will sufficiently reveal the general nature of the disclosure so that others can, by applying the knowledge within the art, easily modify and / or adjust such specific aspects for various applications without undue experimentation and without departing from the overall concept of the disclosure. Therefore, based on the teachings and guidance presented herein, such adjustments and modifications are intended to be within the meaning and scope of equivalents of the disclosed aspects.

[0145] It should be understood that the Detailed Description section, rather than the Summary and Abstract sections, is intended to be used to interpret the claims. The Summary and Abstract sections may set forth one or more (but not necessarily all) aspects of the disclosure as contemplated by the inventors, and thus are not intended to limit the disclosure and the appended claims in any way. The breadth and scope of the protected subject matter should not be limited by any of the above-described aspects, but should be defined only in accordance with the appended claims and their equivalents.

Claims

1. A substrate alignment device, comprising: an illumination system configured to receive a source radiation beam from a radiation source and direct the source radiation beam toward a pupil plane; an optical component positioned at the pupil plane and configured to direct the split beams of the source radiation beam towards a plurality of alignment marks on a substrate; at least one objective lens module disposed between the optical component and the substrate and configured to focus the separated beams of the source radiation beam on corresponding separated marks of the plurality of alignment marks; as well as An interferometer is configured to receive a diffracted radiation beam that is diffracted from the plurality of alignment marks, collected by the at least one objective lens module, and directed to the interferometer by the optical component. 2 . The substrate alignment apparatus according to claim 1 , wherein the interferometer is a self-referencing interferometer. 3 . The substrate alignment apparatus according to claim 2 , wherein the optical component is a scanning galvanometer mirror having at least one degree of freedom. 4 . The substrate alignment apparatus according to claim 3 , wherein the at least one objective lens module is a large field of view telecentric objective lens module. 5 . The substrate alignment apparatus according to claim 4 , wherein the large field-of-view telecentric objective lens module has a numerical aperture of at least 0.

6. 6 . The substrate alignment apparatus according to claim 4 , wherein the large-field-of-view telecentric objective lens module has a field of view of at least 5 mm. 7 . The substrate alignment apparatus according to claim 4 , wherein the large-field-of-view telecentric objective lens module has a wavelength range greater than or equal to 500 nm and less than or equal to 900 nm. 8 . The substrate alignment apparatus according to claim 1 , wherein the at least one objective lens module comprises a plurality of objective lenses disposed at different positions above the substrate.

9. The substrate alignment apparatus of claim 8, wherein the optical component is a scanning galvanometer mirror having at least one degree of freedom to direct the split beam and the diffracted radiation beam of the source radiation beam. 10 . The substrate alignment apparatus according to claim 9 , wherein the at least one degree of freedom of the scanning mirror is an angle formed between a normal vector at a surface of the scanning mirror and a normal vector at a surface of the substrate.

11. The substrate alignment apparatus of claim 9, wherein each objective lens is arranged to focus one of the split beams of the source radiation beam and to collect at least one of the diffracted radiation beams. 12 . The substrate alignment apparatus according to claim 9 , wherein the scanning galvanometer mirror has two degrees of freedom.

13. The substrate alignment apparatus of claim 1, wherein the radiation source generates monochromatic radiation.

14. The substrate alignment apparatus of claim 1, wherein the radiation source generates radiation having a plurality of wavelengths. The substrate alignment apparatus according to claim 1 , wherein the optical component is a grating.

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