Positioning system for optical element of metrology device

Abstract

A positioning system for an optical element, such as an objective lens of a metrology device (e.g., an overlay measurement device used in a semiconductor manufacturing process), is described. The positioning system comprises an objective table and a positioning device. The positioning device includes at least one flexible support coupled with the stage, the at least one flexible support configured to be relatively rigid in an axial direction of the positioning device and relatively flexible in other directions. The positioning device includes a base coupled to at least one flexible support, the base configured to be actuated to move in an axial direction and in turn to move the stage. The positioning device includes a guide configured to couple the base to the frame of the metrology device, the guide configured to bend when the base is actuated.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. application No. 63 / 409,354, filed on September 23, 2022, the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to a positioning system for an optical element of a measurement device. Background Art

[0004] Lithographic projection equipment can be used, for example, in the manufacture of integrated circuits (ICs). A pattern forming device (e.g., a mask) can include or provide a pattern corresponding to a single layer of the IC (a "design layout"), and the pattern can be transferred to a target portion (e.g., including one or more dies) on a substrate (e.g., a silicon wafer) that has been coated with a layer of radiation-sensitive material ("resist") by methods such as irradiating the target portion through a pattern on the pattern forming device. Typically, a single substrate includes multiple adjacent target portions, and the pattern is continuously transferred to the target portion by the lithographic projection equipment one target portion at a time. In one type of lithographic projection equipment, in one operation, the pattern on the entire pattern forming device is transferred to one target portion. Such a device is generally referred to as a stepper. In an alternative device, generally referred to as a step-scanning device, the projection beam is scanned on the pattern forming device in a given reference direction (the "scanning" direction), while the substrate is synchronously moved parallel to or antiparallel to the reference direction. Different portions of the pattern on the pattern forming device are gradually transferred to one target portion.

[0005] Before the pattern is transferred from the pattern forming device to the substrate, the substrate may undergo various processes, such as priming, resist coating, and soft baking. After exposure, the substrate may undergo other processes ("post-exposure processes"), such as post-exposure baking (PEB), development, hard baking, and measurement / inspection of the transferred pattern. This series of processes is used as the basis for manufacturing a single layer of a device (e.g., an IC). The substrate may then undergo various processes, such as etching, ion implantation (doping), metallization, oxidation, deposition, chemical mechanical polishing, etc., all of which are intended to complete a single layer of the device. If several layers are required in the device, the entire process or a variation of the entire process is repeated for each layer. Ultimately, the device will be present in each target portion on the substrate. The devices are then separated from each other by techniques such as cutting or sawing so that the individual devices can be mounted on a carrier, connected to pins, etc.

[0006] Therefore, manufacturing devices such as semiconductor devices generally involves using a variety of manufacturing processes to process substrates (e.g., semiconductor wafers) to form a variety of features and multiple layers of the device. These layers and features are generally manufactured and processed using, for example, deposition, lithography, etching, deposition, chemical mechanical polishing, and ion implantation. Multiple devices can be manufactured on multiple dies on a substrate and then separated into separate devices. The device manufacturing process can be considered a patterning process. The patterning process involves a patterning step, such as optical and / or nanoimprint lithography using a pattern forming device in a lithographic device to transfer the pattern on the pattern forming device to the substrate, and generally but optionally involves one or more related pattern processing steps, such as resist development by a developing device, baking the substrate using a baking tool, etching the pattern using an etching device, deposition, etc.

[0007] Photolithography is a central step in the manufacture of devices such as ICs, where patterns formed on a substrate define the functional elements of a device such as a microprocessor, memory chip, etc. Similar photolithography techniques are also used to form flat panel displays, microelectromechanical systems (MEMS), and other devices.

[0008] As semiconductor manufacturing processes continue to advance, the size of functional elements has continued to decrease, while the number of functional elements (e.g., transistors) per device has steadily increased for decades, following a trend generally referred to as "Moore's Law." In the current state of the art, device layers are fabricated using photolithographic projection equipment that projects a design layout onto a substrate using illumination from a deep ultraviolet illumination source, thereby producing individual functional elements having dimensions well below 100 nm (i.e., less than half the wavelength of the radiation from the illumination source (e.g., a 193 nm illumination source)).

[0009] This process of printing features with dimensions smaller than the classical resolution limit of a lithographic projection apparatus is often referred to as low-k1 lithography, according to the resolution formula CD = k1 × λ / NA, where λ is the wavelength of radiation employed (currently 248 nm or 193 nm in most cases), NA is the numerical aperture of the projection optics in the lithographic projection apparatus, CD is the "critical dimension" - usually the minimum feature size printed, and k1 is an empirical resolution factor. In general, the smaller the k1, the more difficult it is to reproduce on a substrate a pattern similar in shape and size to that designed by the designer to achieve specific electrical functions and performance. To overcome these difficulties, complex fine-tuning steps are applied to the lithographic projection apparatus, the design layout, or the patterning device. These complex fine-tuning steps include, for example, but not limited to, optimization of NA and optical coherence settings, customized illumination schemes, use of phase-shifted patterning devices, optical proximity correction (OPC, sometimes also called "optical and process correction") in the design layout, or other methods often defined as "resolution enhancement techniques" (RET). Summary of the invention

[0010] A positioning system (and associated method) for an optical element (e.g., an objective lens) of a measurement device is described. Compared to existing systems, the design of the present system provides three-dimensional (e.g., X, Y, and Z) motion of a lighter objective stage with repositionable dimensional (e.g., X, Y) actuators. The three degrees of freedom of motion are provided by independent, separate bases that drive the objective stage. The bases are configured to independently move the stage in the X, Y, and / or Z directions at different times and / or simultaneously to accurately position the objective lens (optical element) for measurement. Flexible supports between each base and the objective stage transfer motion from the base to the objective stage via a rigid axial connection. However, the flexible supports provide a sufficiently compliant connection in non-axial directions to reduce or prevent undesired translation, rotation, and / or tilt of the objective stage.

[0011] According to an embodiment, a positioning system for an optical element of a measuring device is provided. The positioning system includes a stage and a positioning device. The positioning device includes at least one flexible support member connected to the stage. The at least one flexible support member is configured to be relatively rigid in the axial direction of the positioning device and relatively flexible in other directions. The positioning device includes a base coupled to the at least one flexible support member. The base is configured to be actuated to move in the axial direction and thereby move the stage. The positioning device includes a guide member configured to couple the base to a frame of the measuring device. The guide member is configured to bend when the base is actuated.

[0012] In some embodiments, the positioning system includes a first positioning device, a second positioning device, and a third positioning device, which are connected to the stage and are configured to move the stage in the X direction, the Y direction, and the Z direction, respectively. The first positioning device, the second positioning device, and the third positioning device can be configured to independently move the stage in the X direction, the Y direction, and the Z direction at different times and / or simultaneously to accurately position the optical element for measurement, the optical element being supported by the stage.

[0013] In some embodiments, the first positioning device includes a single flexible support, the second positioning device includes two flexible supports, and the third positioning device includes at least three flexible supports. In some embodiments, the third positioning device includes four flexible supports positioned at or near four corresponding corners of the stage. In some embodiments, the single flexible support of the first positioning device is located at or near the center of the first side edge of the stage. In some embodiments, the two flexible supports of the second positioning device are located at or near the opposite corners of the second side edge of the stage. The two flexible supports are configured to reduce or prevent undesirable rotation of the stage. In some embodiments, the four flexible supports of the third positioning device are connected to the top surface of the stage and are configured to reduce or prevent undesirable rotation and / or tilting of the stage.

[0014] In some embodiments, four flexible supports of the third positioning device are positioned around a Porro prism of the measurement device.

[0015] In some embodiments, the optical element is an objective lens.

[0016] In some embodiments, the guide comprises two parallel flexible plates positioned on opposite sides of the base. In some embodiments, the frame is a sensor frame of a metrology device.

[0017] In some embodiments, the positioning device is configured to move the optical element for overlay measurement.The overlay measurement may be for a semiconductor wafer, and the overlay measurement may be performed as part of a semiconductor manufacturing process.

[0018] In some embodiments, the positioning device further comprises an actuator coupled to the base, the actuator being configured to move the base, and thereby the stage and the optical element, in an axial direction.

[0019] According to another embodiment, a measurement device is provided. The measurement device includes a radiation source configured to generate radiation directed toward a prism component and an objective lens along an optical path. The measurement device includes a positioning system for the objective lens. The positioning system includes: a stage configured to support the objective lens; and a first positioning device, a second positioning device, and a third positioning device, which are connected to the stage and configured to move the stage in the X direction, the Y direction, and the Z direction, respectively. The positioning device includes at least one flexible support member connected to the stage. At least one flexible support member is configured to be relatively rigid in the axial direction of the positioning device and relatively flexible in other directions. The positioning device includes a base connected to the at least one flexible support member. The base is configured to be actuated to move in the axial direction, and then move the stage and the objective lens to guide the radiation toward a target on a substrate. The positioning device includes a guide configured to connect the base to a frame of the measurement device. The guide is configured to bend when the base is actuated but remain coupled to the frame. The metrology device includes a detector. The detector is configured to receive diffracted and reflected radiation from a target and generate a detection signal.

[0020] In some embodiments, the metrology device includes a second positioning system. The second positioning system is configured to position the second objective lens so as to perform two simultaneous measurements on the same substrate. The second positioning system can be configured so that the distance from one objective lens to another objective lens in the metrology device is, for example, about 48 mm. In some embodiments, the metrology device includes a third positioning system and a fourth positioning system, and the third positioning system and the fourth positioning system are configured to position the third objective lens and the fourth objective lens, respectively, so as to perform two additional simultaneous measurements on the second substrate by the metrology device.

[0021] According to another embodiment, a method for positioning an optical element of a measurement device is provided. The method includes: supporting the optical element with a stage; coupling at least one flexible support of a positioning device to the stage, the at least one flexible support being configured to be relatively rigid in the axial direction of the positioning device and relatively flexible in other directions; coupling a base of the positioning device to the at least one flexible support, the base being configured to be actuated to move in the axial direction and in turn move the stage; coupling the base to a frame of the measurement device using a guide of the positioning device, the guide being configured to bend when the base is actuated; and actuating the base to move in the axial direction, thereby moving the stage and positioning the optical element.

[0022] According to another embodiment, a method performed using a metrology device is provided. The method comprises: generating radiation directed toward a prism component and an objective lens along an optical path using a radiation source of the metrology device; supporting the objective lens using a stage of the metrology device; moving the stage using a first positioning device, a second positioning device, and a third positioning device of a first positioning system of the metrology device, the first positioning device, the second positioning device, and the third positioning device being coupled to the stage and configured to move the stage in an X direction, a Y direction, and a Z direction, respectively; coupling at least one flexible support to the stage, the at least one flexible support being configured to be relatively rigid in an axial direction of the positioning device and relatively flexible in other directions; coupling a base to the at least one flexible support, the base being configured to be actuated to move in the axial direction and thereby move the stage and the objective lens to direct the radiation toward a target on a substrate; coupling the base to a frame of the metrology device using a guide, the guide being configured to bend when the base is actuated but remain coupled to the frame; and receiving diffracted and reflected radiation from the target using a detector and generating a detection signal.

[0023] According to another embodiment, a measurement device having a prism component and an objective lens is provided. The measurement device includes an objective lens positioning system. The objective lens positioning system includes: an objective lens stage, the objective lens stage is configured to support the objective lens; and a first objective lens positioning device, a second objective lens positioning device, and a third objective lens positioning device, the first objective lens positioning device, the second objective lens positioning device, and the third objective lens positioning device are connected to the objective lens stage and are configured to move the objective lens stage in the X direction, the Y direction, and the Z direction, respectively. An objective lens positioning device, comprising: at least one flexible objective lens support, the at least one flexible objective lens support is connected to the objective lens stage, the at least one flexible objective lens support is configured to be relatively rigid in the axial direction of the objective lens positioning device and relatively flexible in other directions; an objective lens base, the objective lens base is connected to the at least one flexible objective lens support, the objective lens base is configured to be actuated to move in the axial direction and thereby move the objective lens stage and the objective lens to direct the radiation toward a target on a substrate; and an objective lens guide, the objective lens guide is configured to couple the objective lens base to a frame of the metrology device, the objective lens guide is configured to bend when the objective lens base is actuated, but remain coupled to the frame. The metrology device includes a prism positioning system. The prism positioning system includes: a prism stage configured to support the prism component; and a first prism positioning device and a second prism positioning device, the first prism positioning device and the second prism positioning device are connected to the prism stage and are configured to move the prism stage in the X direction and the Y direction respectively. The prism positioning device includes: at least one flexible prism support, the at least one flexible prism support is connected to the prism stage, the at least one flexible prism support is configured to be relatively rigid in the axial direction of the prism positioning device and relatively flexible in other directions; a prism base, which is connected to the at least one flexible prism support, the prism base is configured to be actuated to move in the axial direction and in turn move the prism stage and the prism component to direct radiation toward a target on a substrate; and a prism guide, the prism guide is configured to connect the prism base to a frame of a metrology device, the prism guide is configured to bend when the prism base is actuated, but remain connected to the frame.

[0024] According to another embodiment, a method is provided for use with a measurement device having a prism assembly and an objective lens. The method includes: supporting the objective lens with an objective lens stage; and coupling a first objective lens positioning device, a second objective lens positioning device, and a third objective lens positioning device to the objective lens stage, and moving the objective lens stage in an X direction, a Y direction, and a Z direction, respectively. An objective lens positioning device comprises: at least one flexible objective lens support, the at least one flexible objective lens support is coupled to the stage, the at least one flexible objective lens support is configured to be relatively rigid in the axial direction of the objective lens positioning device and relatively flexible in other directions; an objective lens base, the objective lens base is coupled to the at least one flexible objective lens support, the objective lens base is configured to be actuated to move in the axial direction and thereby move the objective lens stage and the objective lens to direct the radiation toward a target on a substrate; and an objective lens guide, the objective lens guide is configured to couple the objective lens base to a frame of the measurement device, the objective lens guide is configured to bend when the objective lens base is actuated, but remain coupled to the frame. The method comprises: supporting a prism component with a prism stage; and coupling a first prism positioning device and a second prism positioning device to the prism stage and moving the prism stage in the X direction and the Y direction, respectively. The prism positioning device includes: at least one flexible prism support, the at least one flexible prism support is connected to the prism stage, the at least one flexible prism support is configured to be relatively rigid in the axial direction of the prism positioning device and relatively flexible in other directions; a prism base, the prism base is connected to the at least one flexible prism support, the prism base is configured to be actuated to move in the axial direction, and in turn moves the prism stage and the prism component to direct radiation toward a target on the substrate; and a prism guide, the prism guide is configured to connect the prism base to the frame of the measurement device, the prism guide is configured to bend when the prism base is actuated, but remain connected to the frame. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The above aspects and other aspects and features will become apparent to those of ordinary skill in the art after reading the following description of specific embodiments in conjunction with the accompanying drawings.

[0026] Figure 1 A lithographic apparatus according to an embodiment is schematically illustrated.

[0027] Figure 2 An embodiment of a lithography cell or cluster according to an embodiment is schematically shown.

[0028] Figure 3 An exemplary inspection system according to an embodiment is schematically depicted.

[0029] Figure 4 An exemplary metrology technique according to an embodiment is schematically depicted.

[0030] Figure 5 The relationship between the radiation illumination point and the measurement target of the inspection system according to one embodiment is described.

[0031] Figure 6 An exemplary metrology system configured for inspecting two substrates (supported by two corresponding wafer stages) using two corresponding sensors using two optical axes is shown in accordance with an embodiment.

[0032] Figure 7 An exemplary metrology system having two sets of positioning elements and optical components coupled to one central sensor rather than multiple sensors is shown in accordance with an embodiment. Figure 6 Two sensors are shown.

[0033] Figure 8 A mechanical system configured to achieve a desired movement of an objective lens included in a metrology system is shown according to an embodiment.

[0034] Fig. 9 A positioning system for an optical element such as an objective of a metrology device according to an embodiment is shown.

[0035] Fig.10 A metrology device comprising a second positioning system according to an embodiment is shown.

[0036] Fig.11 A measurement device including a third positioning system and a fourth positioning system according to an embodiment is shown.

[0037] Fig.12 According to an embodiment, Fig.11 A perspective view of the measurement equipment shown in FIG.

[0038] Fig.13 A metrology device with a prism assembly and an objective lens is shown according to an embodiment, the metrology device having a corresponding prism and objective lens positioning system.

[0039] Fig.14 A measurement method according to an embodiment is shown.

[0040] Fig.15 is a block diagram of an exemplary computer system according to an embodiment. DETAILED DESCRIPTION

[0041] In semiconductor device manufacturing, metrology operations typically involve determining the position of a metrology mark (or marks) and / or other targets in a layer of a semiconductor device structure. The position is typically determined by illuminating the metrology mark with radiation and comparing the characteristics of different diffraction orders of radiation reflected from the metrology mark. This technique is used to measure overlay, alignment, and / or other parameters.

[0042] Existing metrology systems are configured to move different objective lenses in different directions relative to a central sensor. The objective lens typically includes a plurality of lenses supported in a housing. In such systems, a dual Porro prism is typically used for path length compensation. The dual Porro prism directs incident light toward the objective lens. The Porro prism typically moves in a 1:2 ratio to the movement of the corresponding objective lens (e.g., XY direction). A dual Porro prism includes two Porro prisms, wherein a single Porro prism includes two reflective surfaces at 90 degrees. The Porro prisms are rotated 90 degrees relative to each other about the z-axis. Each Porro prism compensates for path length and provides a steered radiation beam in one degree of freedom (e.g., X or Y). The mechanical coupling device for the dual Porro prism movement is coupled to the movement of the objective lens in these systems through a connection at half the length of some (e.g., XY direction) flexures, and the first dimension (e.g., Z direction) actuator is connected in series to the other dimension (e.g., XY) actuator to move the entire Porro prism and objective lens system to focus radiation on a target on a substrate. This design has a large moving mass in the Z direction due to the XY actuator and the Porro prism. The Lorentz motors included in such a system are inefficient due to the required spacing between the coils and magnets to allow Z-direction motion. Furthermore, the thermal load on the objective lenses is increased due to the proximity of the XY actuators, adequate prism positioning is not provided due to the inherent inefficiency of the XY flexure, additional external fine alignment methods are required to focus the radiation on the objective lenses, and multiple pitch distances (>2x) between the objective lenses are required for simultaneous measurements on a single substrate.

[0043] Advantageously, the present system(s) and method(s) provide an improved positioning system for an optical element (e.g., an objective lens) of a measurement device. Compared to existing systems, the design of the present system provides three-dimensional (e.g., X, Y, and Z) motion of a lighter objective stage with a repositioned dimensional (e.g., X, Y) actuator. The three degrees of freedom of motion are provided by an independent, separate base that drives the objective stage. The base is configured to independently move the stage in the X, Y, and / or Z directions at different times and / or simultaneously to accurately position the objective lens (optical element) for measurement. A flexible support between each base and the objective stage transfers motion from the base to the objective stage via a rigid axial connection. However, the flexible support provides a sufficiently compliant connection in a non-axial direction to reduce or prevent undesired translation, rotation, and / or tilt of the objective stage. This reduces the moving mass in the Z direction, reduces the spacing required between the actuator coils and magnets to allow Z direction motion, reduces thermal loading on the objective, provides adequate prism positioning, eliminates the need for external fine alignment methods to focus radiation on the objective, and eliminates the need for multiple pitch distances between objectives for simultaneous measurements on a single substrate.

[0044] By way of brief introduction, the following description relates to semiconductor device manufacturing and patterning processes. The following paragraphs also describe several components of systems and / or methods for semiconductor device measurement. These systems and methods can be used, for example, to measure overlay, alignment, etc., during semiconductor device manufacturing, or for other operations.

[0045] Although specific reference may be made herein to the measurement of overlay, alignment or other parameters, and the manufacture of integrated circuits (ICs) for semiconductor devices, it should be understood that the description herein has many other possible applications. For example, the description herein may be used in the manufacture of integrated optical systems, guidance and detection patterns for magnetic domain memories, liquid crystal display panels, thin film magnetic heads, etc. Those skilled in the art will appreciate that in the context of these alternative applications, any use of the terms "reticle", "wafer" or "die" herein should be considered interchangeable with the more general terms "mask", "substrate" and "target portion", respectively.

[0046] The term "projection optics" as used herein should be interpreted broadly to include various types of optical systems, including, for example, refractive optics, reflective optics, apertures, and reflective-refractive optics. The term "projection optics" may also include components for guiding, shaping, or controlling a radiation projection beam, either collectively or individually, operating according to any of these design types. The term "projection optics" may include any optical component in a lithographic projection apparatus, regardless of where the optical component is located on the optical path of the lithographic projection apparatus. The projection optics may include optical components for shaping, conditioning, and / or projecting radiation from a source before the radiation passes through a patterning device, and / or optical components for shaping, conditioning, and / or projecting radiation after the radiation passes through a patterning device. Projection optics typically do not include a source and a patterning device.

[0047] Figure 1 An embodiment of a lithographic apparatus LA is schematically shown. The apparatus comprises an illumination system (illuminator) IL configured to condition a radiation beam B (e.g., UV radiation, DUV radiation, or EUV radiation); a support structure (e.g., a mask stage) MT constructed to support a patterning device (e.g., a mask) MA and connected to a first positioning device PM configured to accurately position the patterning device according to determined parameters; a substrate stage (e.g., a wafer stage) WT (e.g., WTa, WTb, or both) configured to hold a substrate (e.g., a wafer coated with resist) W and connected to a second positioning device PW configured to accurately position the substrate according to determined parameters; and a projection system (e.g., a refractive projection lens system) PS configured to project a pattern imparted to the radiation beam B by the patterning device MA onto a target portion C (e.g., comprising one or more dies and commonly referred to as a field) of the substrate W. The projection system is supported on a reference frame RF. As shown, the apparatus is of a transmissive type (e.g., employing a transmissive mask). Alternatively, the device may be reflective (eg, using a programmable mirror array, or using a reflective mask).

[0048] The illuminator IL receives a radiation beam from a radiation source SO. For example, when the source is an excimer laser, the source and the lithographic apparatus may be separate entities. In this case, the radiation source is not considered to constitute a part of the lithographic apparatus, the radiation beam being transmitted from the source SO to the illuminator IL by means of a beam delivery system BD, which for example comprises suitable directional mirrors and / or a beam expander. In other cases, for example, when the source is a mercury lamp, the source may be an integral part of the apparatus. The source SO and the illuminator IL, together with the beam delivery system BD if necessary, may be referred to as a radiation system.

[0049] The illuminator IL may vary the intensity distribution of the radiation beam. The illuminator may be arranged to limit the radial extent of the radiation beam so that the intensity distribution is non-zero within an annular region in a pupil plane of the illuminator IL. Additionally or alternatively, the illuminator IL may be operable to limit the distribution of the beam in the pupil plane so that the intensity distribution is non-zero in a plurality of equally spaced segments in the pupil plane. The intensity distribution of the radiation beam in the pupil plane of the illuminator IL may be referred to as an illumination pattern.

[0050] The illuminator IL may comprise an adjustment device AD ​​configured to adjust the (angular / spatial) intensity distribution of the beam. Typically, at least the outer radial extent and / or the inner radial extent (typically referred to as σ-outer and σ-inner, respectively) of the intensity distribution in a pupil plane of the illuminator may be adjusted. The illuminator IL may be operable to change the angular distribution of the light beam. For example, the illuminator may be operable to change the number and angular extent of the segments in the pupil plane, in which the intensity distribution is non-zero. By adjusting the intensity distribution of the beam in the pupil plane of the illuminator, different illumination modes may be achieved. For example, by limiting the radial and angular extent of the intensity distribution in the pupil plane of the illuminator IL, the intensity distribution may have a multipolar distribution, such as, for example, a dipole, quadrupole or hexapole distribution. For example, by inserting an optical device providing the illumination mode into the illuminator IL or using a spatial light modulator, a desired illumination mode may be obtained.

[0051] The illuminator IL may be operable to change the polarization of the beam, and may be operable to adjust the polarization using an adjuster AD. The polarization state of the radiation beam on the pupil plane of the illuminator IL may be referred to as a polarization mode. Using different polarization modes may allow greater contrast to be achieved in the image formed on the substrate W. The radiation beam may be unpolarized. Alternatively, the illuminator may be arranged to linearly polarize the radiation beam. The polarization direction of the radiation beam may vary on the pupil plane of the illuminator IL. The polarization direction of the radiation may be different in different regions in the pupil plane of the illuminator IL. The polarization state of the radiation may be selected according to the illumination mode. For a multi-pole illumination mode, the polarization of each pole of the radiation beam may generally be perpendicular to the position vector of the pole in the pupil plane of the illuminator IL. For example, for a dipole illumination mode, the radiation may be linearly polarized in a direction substantially perpendicular to a line that bisects two opposing segments of the dipole. The radiation beam may be polarized in one of two different orthogonal directions, which may be referred to as an X polarization state and a Y polarization state. For a quadrupole illumination mode, the radiation in the segments of each pole may be linearly polarized in a direction substantially perpendicular to a line bisecting the segment. This polarization mode may be referred to as XY polarization. Similarly, for a hexapole illumination mode, the radiation in the segments of each pole may be linearly polarized in a direction substantially perpendicular to a line bisecting the segment. This polarization mode may be referred to as TE polarization.

[0052] In addition, the illuminator IL typically includes various other components, such as an integrator IN and a condenser CO. The illumination system may include various types of optical components for directing, shaping, or controlling the radiation, such as refractive, reflective, magnetic, electromagnetic, electrostatic or other types of optical components, or any combination thereof. Thus, the illuminator provides a conditioned radiation beam B having a desired uniformity and intensity distribution in the cross-section of the radiation beam B.

[0053] The support structure MT supports the patterning device in a manner that depends on the orientation of the patterning device, the design of the lithographic apparatus, and other conditions (such as, for example, whether the patterning device is maintained in a vacuum environment). The support structure can use mechanical, vacuum, electrostatic or other clamping techniques to hold the patterning device. The support structure can be a frame or a stage, for example, which can be fixed or movable as required. The support structure can ensure that the patterning device is in a desired position, for example relative to a projection system. The terms "reticle" or "mask" used herein can be considered to be synonymous with the more general term "patterning device".

[0054] The term "patterning device" as used herein should be broadly interpreted as referring to any device that can be used to impart a pattern in a target portion of a substrate. In one embodiment, the patterning device is any device that can be used to impart a pattern in a cross-section of the radiation beam to form a pattern in the target portion of the substrate. It should be noted that the pattern imparted to the radiation beam may not exactly correspond to the desired pattern in the target portion of the substrate, for example if the pattern includes phase-shifting features or so-called assist features. Typically, the pattern imparted to the radiation beam will correspond to a specific functional layer in a device formed in the target portion of the device, such as an integrated circuit.

[0055] The patterning device may be transmissive or reflective. Examples of patterning devices include masks, programmable mirror arrays, and programmable LCD panels. Masks are well known in lithography and include mask types such as binary, alternating phase shift, and attenuated phase shift, as well as various hybrid mask types. An example of a programmable mirror array employs a matrix arrangement of small mirrors, each of which can be individually tilted to reflect an incoming radiation beam in different directions. The tilted mirrors impart a pattern in the radiation beam reflected by the matrix of mirrors.

[0056] The term "projection system" should be broadly interpreted as including any type of projection system, including refractive, reflective, catadioptric, magnetic, electromagnetic and electrostatic optical systems, or any combination thereof, as appropriate to the exposure radiation used, or to other factors such as the use of immersion liquid or the use of a vacuum. The term "projection lens" as used herein may be considered synonymous with the more general term "projection system".

[0057] The projection system PS may include a plurality of optical (e.g., lens) elements, and may further include an adjustment mechanism configured to adjust one or more of the optical elements to correct aberrations (phase variations across the pupil plane over the entire field). To achieve this, the adjustment mechanism may be operable to manipulate one or more optical (e.g., lens) elements within the projection system PS in one or more different ways. The projection system may have a coordinate system in which the optical axis of the projection system extends in the z direction. The adjustment mechanism may be operable to perform any combination of the following: displacing one or more optical elements; tilting one or more optical elements; and / or deforming one or more optical elements. The displacement of the optical element may be in any direction (x, y, z, or a combination thereof). Although rotation about the z-axis may be used for non-rotationally symmetric aspheric optical elements, the tilt of the optical element is typically outside a plane perpendicular to the optical axis by rotating about an axis in the x and / or y directions. The deformation of the optical element may include a low-frequency shape (e.g., astigmatism) and / or a high-frequency shape (e.g., a free-form aspheric surface). For example, deformation of the optical element may be performed by applying a force on one or more sides of the optical element using one or more actuators and / or by heating one or more selected regions of the optical element using one or more heating elements. Typically, it is not possible to adjust the projection system PS to correct for apodization (transmission variations in the pupil plane). When designing a patterning device (e.g., mask) MA for the lithographic apparatus LA, a transmission map of the projection system PS may be used. Using computational lithography techniques, the patterning device MA may be designed to at least partially correct for apodization.

[0058] The lithographic apparatus may be of a type having two (dual stage) or more stages (e.g. two or more substrate tables WTa, WTb, two or more patterning device tables, a substrate table WTa and a table WTb below the projection system, without a dedicated substrate table for example to facilitate measurement and / or cleaning etc.). In such a "multi-stage" machine, the additional stages may be used in parallel, or preparatory steps may be performed on one or more stages while one or more other stages are being used for exposure. For example, alignment measurements may be made using an alignment sensor AS and / or level (height, tilt etc.) measurements may be made using a level sensor LS.

[0059] 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) to fill the space between the projection system and the substrate. Immersion liquid may also be applied to other spaces in the lithographic apparatus, for example, between the patterning device and the projection system. Immersion techniques for increasing the numerical aperture of the projection system are well known in the art. The term "immersion" as used herein does not mean that structures such as the substrate must be immersed in the liquid, but only means that the liquid is located between the projection system and the substrate during exposure.

[0060] In operation of the lithographic apparatus, a radiation beam is conditioned and provided by an illumination system IL. The radiation beam B is incident on a patterning device (e.g. a mask) MA held on a support structure (e.g. a mask table) MT and is patterned by the patterning device. After having passed through the patterning device MA, the radiation beam B passes through a projection system PS which focuses the radiation beam onto a target portion C of the substrate W. With the aid of a second positioning device PW and a position sensor IF (e.g. an interferometric device, a linear encoder, a 2-D encoder or a capacitive sensor), the substrate table WT can be precisely moved, for example to position different target portions C in the path of the radiation beam B. Similarly, for example, after mechanical acquisition from a mask library or during scanning, the first positioning device PM and a further position sensor (in Figure 1 A further position sensor (not clearly shown in the figure) can be used to accurately customize the pattern forming device MA relative to the path of the radiation beam B. In general, movement of the support structure MT can be achieved with the help of a long-stroke module (coarse positioning) and a short-stroke module (fine positioning), which form part of the first positioning device PM. Similarly, movement of the substrate table WT can be achieved using a long-stroke module and a short-stroke module that form part of the second positioning device PW. In the case of a stepper (as opposed to a scanner), the support structure MT may be connected only to the short-stroke actuator, or may be fixed. The pattern forming device MA and the substrate W can be aligned using pattern forming device alignment marks M1, M2 and substrate alignment marks P1, P2. Although the substrate alignment marks as shown occupy dedicated target portions, the substrate alignment marks may be located in the space between target portions (these are called scribe alignment marks). Similarly, where more than one die is provided on the pattern forming device MA, the pattern forming device alignment marks may be located between the dies.

[0061] The described apparatus can be used in at least one of the following modes. In step mode, the support structure MT and the substrate table WT remain substantially stationary while the pattern imparted to the radiation beam is projected onto the target portion C once (i.e., a single static exposure). The substrate table WT is then moved in the X and / or Y direction so that different target portions C can be exposed. In step mode, the maximum size of the exposure field limits the size of the target portion C imaged in a single static exposure. In scan mode, the support structure MT and the substrate table WT are scanned synchronously while the pattern imparted to the radiation beam is projected onto the target portion C (i.e., a single dynamic exposure). The speed and direction of the substrate table WT relative to the support structure MT can be determined by the (reduced) magnification and image reversal characteristics of the projection system PS. In scan mode, the maximum size of the exposure field limits the width of the target portion (in the non-scanning direction) in a single dynamic exposure, while the length of the scanning movement determines the height of the target portion (in the scanning direction). In another mode, the support structure MT remains substantially stationary, thereby being used to hold a programmable pattern forming device, and the substrate table WT is moved or scanned while the pattern imparted to the radiation beam is projected onto the target portion C. In this mode, a pulsed radiation source is typically 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 using a programmable patterning device, for example a programmable mirror array of the type mentioned above.

[0062] Combinations and / or variations on the above described modes of use or entirely different modes of use may also be employed.

[0063] Before or after exposure, the substrate may be processed in, for example, a track or developer coating system (a tool that typically applies a resist layer to a substrate and develops the exposed resist) or a metrology or inspection tool. Where applicable, the disclosure herein may be applied to such and other substrate processing tools. Furthermore, a substrate may be processed more than once, such as to produce a multi-layer IC, so that the term "substrate" as used herein may also refer to a substrate that already includes multiple processed layers.

[0064] The terms “radiation” and “beam” as used herein with respect to lithography include all types of electromagnetic radiation, including ultraviolet (UV) or deep ultraviolet (DUV) radiation (e.g., having a wavelength of 365 nm, 248 nm, 193 nm, 157 nm, or 126 nm) and extreme ultraviolet (EUV) radiation (e.g., having a wavelength in the range of 5 nm to 20 nm), as well as particle beams, such as ion beams or electron beams.

[0065] Various patterns on or provided by a pattern forming device may have different process windows. That is, the space of process variables that will produce patterns within the specifications. Examples of pattern specifications associated with potential system defects include inspections for necking, line pullback, line thinning, CD, edge placement, overlap, resist top loss, resist undercut and / or bridging. The process window of a pattern on a pattern forming device or the region of the process window can be obtained by merging (e.g., overlapping) the process windows of each individual pattern. The boundaries of the process window of a group of patterns include the boundaries of the process windows of some individual patterns. In other words, these individual patterns limit the process window of the pattern group.

[0066] like Figure 2 As shown, the lithography apparatus LA may form part of a lithography cell LC, which is sometimes also referred to as a lithography cell or lithography cluster, and which also includes equipment for performing pre-exposure and post-exposure processing on a substrate. Conventionally, these equipment include one or more spin coaters SC for depositing one or more resist layers, one or more developing devices for developing the exposed resist, one or more cooling plates CH and / or one or more baking plates BK. A substrate carrier or robot RO picks up one or more substrates from input / output ports I / O1, I / O2, moves the one or more substrates between different processing equipment, and delivers the one or more substrates to a loading bay LB of the lithography apparatus. These equipment are generally collectively referred to as a track or development and coating system, which is under the control of a track or development and coating system control unit TCU, which itself is controlled by a supervisory control system SCS, which also controls the lithography apparatus through a lithography control unit LACU. Therefore, different equipment may be operable to maximize productivity and processing efficiency.

[0067] In order to correctly and consistently expose a substrate exposed by a lithographic apparatus and / or to monitor a portion of a patterning process (e.g., a device manufacturing process) that includes at least one pattern transfer step (e.g., an optical lithography step), it is desirable to inspect a substrate or other object to measure or determine one or more properties, such as alignment, overlay (the overlay may be, for example, between structures in overlapping layers or between structures in the same layer that have been provided separately from the layer by, for example, a double patterning process), line width, critical dimension (CD), focus offset, material properties, etc. Therefore, a manufacturing facility in which a lithography cell LC is located typically also includes measuring some or all substrates W ( Figure 1 ) or other objects in the lithography cell. The measurement system may be part of the lithography cell LC, for example, the measurement system may be the lithography apparatus LA (eg, the alignment sensor AS ( Figure 1 )).

[0068] The one or more measured parameters may include, for example, alignment, overlap between successive layers formed in or on a patterned substrate, critical dimensions (CD) of features formed on or on the patterned substrate (e.g., critical line width), focus or focus error of an optical lithography step, dose or dose error of an optical lithography step, optical aberrations of an optical lithography step, etc. Such measurements are typically performed on one or more dedicated metrology targets provided on the substrate. The measurements may be performed after resist development but before etching, after etching, after deposition, and / or at other times.

[0069] There are various techniques for measuring structures formed during the patterning process, including the use of scanning electron microscopes, image-based measurement tools, and / or various specialized tools. A rapid and non-invasive form of a specialized metrology tool is one in which a radiation beam is directed onto a target on the surface of a substrate and the properties of the scattered (diffraction / reflection) beam are measured. By evaluating one or more properties of the radiation scattered by the substrate, one or more properties of the substrate can be determined. Traditionally, this may be referred to as diffraction-based metrology. Applications of such diffraction-based metrology include measurement of overlay, alignment, and the like. For example, overlay and / or alignment may be measured by comparing multiple portions of a diffraction spectrum (e.g., comparing different diffraction orders in the diffraction spectrum of a periodic grating).

[0070] Thus, in a device manufacturing process (e.g., a patterning process or a lithography process), a substrate or other object may be subjected to various types of measurements during or after the process. The measurements may determine whether a particular substrate is defective, may establish adjustments to the process and equipment used in the process (e.g., aligning two layers on a substrate or aligning a patterning device with a substrate), may measure the performance of the process and equipment, or may be used for other purposes. Examples of measurements include optical imaging (e.g., optical microscopy), non-imaging optical measurements (e.g., diffraction-based measurements, such as ASML YieldStar metrology tools, ASML SMASH metrology systems), mechanical measurements (e.g., profiling using a stylus, atomic force microscope (AFM)), and / or non-optical imaging (e.g., scanning electron microscope (SEM)). U.S. Patent No. 6,961,116, which is incorporated herein by reference in its entirety, describes a self-referencing interferometer that produces two overlapping and relatively rotated images of an alignment mark, detects the intensity in a pupil plane in which a Fourier transform of the images is induced to interfere, and extracts position information from the phase difference between the diffraction orders of the two images, which phase difference manifests itself as intensity variations in the interfered orders.

[0071] The measurement results may be provided directly or indirectly to the supervisory control system SCS. If an error is detected, the exposure of subsequent substrates (especially if the inspection can be completed quickly and quickly enough so that one or more other substrates in the batch of substrates are still to be exposed) and / or the subsequent exposure of the exposed substrate may be adjusted. In addition, the exposed substrate may be stripped and reprocessed to improve yield, or discarded to avoid further processing of the substrate known to be defective. In the case where only some target portions of the substrate are defective, further exposure may be performed only on those target portions that meet the specifications. Other manufacturing process adjustments are contemplated.

[0072] The metrology system may be used to determine one or more properties of a substrate structure, and in particular, to determine how one or more properties of different substrate structures vary, or how different layers of the same substrate structure vary from layer to layer. The metrology system may be integrated into the lithographic apparatus LA or the lithocell LC, or may be a standalone device.

[0073] In order to enable measurement, one or more targets are typically specifically provided on the substrate. Typically, the target is specially designed and may include a periodic structure. For example, the target on the substrate may include one or more 1-D periodic structures (e.g., geometric features such as gratings, etc.), and the one or more 1-D periodic structures are printed so that after development, the periodic structure features are formed by solid resist lines. As another example, the target may include one or more 2-D periodic structures (e.g., gratings), and the one or more 2-D periodic structures are printed so that after development, the one or more periodic structures are formed by solid resist columns or vias in the resist. The bars, columns or vias may be alternatively etched into the substrate (e.g., etched into one or more layers on the substrate).

[0074] Figure 3 An exemplary metrology (inspection) system 10 that can be used to detect overlay, alignment, and / or perform other metrology operations is depicted. The exemplary metrology (inspection) system 10 includes a radiation or illumination source 2 that projects or otherwise illuminates radiation onto a substrate W (e.g., the substrate W may typically include metrology marks). The redirected radiation is passed to a sensor, such as a spectrometer detector 4 and / or other sensor, which measures the spectrum (intensity as a function of wavelength) of the specularly reflected and / or diffracted radiation, such as Figure 4 The sensor may generate a measurement signal conveying measurement data representative of the characteristics of the reflected radiation. Based on this data, the structure or profile of the detected spectrum may be generated by one or more processors PRO (a generalized example of one or more processors PRO is shown in FIG. Figure 4 ) or reconstructed through other operations.

[0075] As in Figure 1 In the lithographic apparatus LA in FIG. 1 , one or more substrate tables ( Figure 4 (not shown) to hold the substrate W during the measurement operation. One or more substrate tables may be used with Figure 1 The substrate tables WT (WTa or WTb or both) are similar or identical in form. In the example where the inspection system 10 is integrated with the lithographic apparatus, the one or more substrate tables may even be the same substrate table. Coarse and fine positioning devices may be provided and configured to accurately position the substrate relative to the measuring optical system. Various sensors and actuators are provided, for example, to obtain the position of the target portion of interest (e.g., measurement marks) of the structure and bring the target portion of interest to a position below the objective lens (lens). Typically, many measurements will be made on the target portion of the structure at different positions across the substrate W. The objective lens and / or the substrate support may be moved in the X-direction and the Y-direction to obtain different targets, and may be moved in the Z-direction to obtain the desired position of the target portion relative to the focus of the optical system. It is convenient to consider and describe the operation as if the objective lens is brought to different positions relative to the substrate. Provided that the relative position of substrate and optical system is correct, it is in principle irrelevant which of the objective and / or the base is moving or both are moving, or a combination of one part of the optical system moving (e.g. in Z and / or tilt direction) while the rest of the optical system is stationary and the substrate is moving (e.g. in X and Y direction, but optionally also in Z and / or tilt direction).

[0076] For typical metrology measurements, the target (portion) 30 on the substrate W may be a 1-D grating that is printed so that after development, the bars are formed by solid resist lines (e.g., which may be covered by a deposited layer) and / or other materials. Alternatively, the target 30 may be a 2-D grating that is printed so that after development, the grating is formed by solid resist pillars and / or other features in the resist.

[0077] The bars, pillars, vias, and / or other features may be etched into or onto the substrate (e.g., etched into one or more layers on the substrate), deposited on the substrate, covered by a deposited layer, and / or have other properties. The target (portion) 30 (e.g., of the bars, pillars, vias, etc.) is sensitive to process variations in the patterning process (e.g., optical aberrations in the lithographic projection apparatus, such as in the projection system, focus variations, dose variations, etc.), such that process variations manifest as variations in the target 30. Thus, measurement data from the target 30 may be used to determine adjustments to one or more manufacturing processes, and / or used as a basis for making actual adjustments.

[0078] For example, the measured data from the target 30 may indicate an overlap of layers of a semiconductor device. The measurement data from the target 30 may be used (e.g., by one or more processors PRO and / or other processors) to determine one or more semiconductor device manufacturing process parameters based on the overlap, and to determine adjustments to semiconductor device manufacturing equipment based on one or more determined semiconductor device manufacturing process parameters. In some embodiments, this may include, for example, stage position adjustments, or this may include determining adjustments to mask design, measurement target design, semiconductor device design, intensity of radiation, incident angle of radiation, wavelength of radiation, pupil size and / or shape, resist material, and / or other process parameters.

[0079] Figure 5 A plan view of a typical target (eg, metrology mark) 30 is shown, and Figure 4 The range of a typical radiation illumination spot S in a system. Typically, in order to obtain a diffraction spectrum that is not interfered with by surrounding structures, in one embodiment, the target 30 is a periodic structure (e.g., a grating) that is larger than the width (e.g., diameter) of the illumination spot S. The width of the spot S may be smaller than the width and length of the target. In other words, the target is "underfilled" by illumination, and the diffraction signal is substantially free of any signal from product features, etc., other than the target itself. For example, the illumination device may be configured to provide illumination of uniform intensity at the back focal plane of the objective. Alternatively, the illumination may be limited to an axial direction or an off-axis direction, for example by including an aperture in the illumination path.

[0080] Figure 6 An exemplary measurement system 600 is shown, which is configured to use two optical axes 606 and 608, using two corresponding sets of optical components and positioning elements ( Figure 6 604 (supported by two respective wafer stages 603 and 605). The wafer stages 603 and / or 605 in such a system typically have only four degrees of freedom (X, Y, ΔY, Rz). Therefore, the positioning system for the second sensor 612 requires at least an X-axis (in this example) degree of freedom (relative to the positioning system for the first sensor 610) to accommodate the ΔX error between the two substrates (wafers) 602 and 604. A second degree of freedom (e.g., a Y-axis degree of freedom) of the positioning system of the second sensor 612 may also be advantageous.

[0081] Note that the descriptions of the various axes (e.g., X, Y, and Z axes) provided herein are intended to provide the reader with a clearer understanding of the described (multiple) systems, rather than to limit the components of such systems to the specific axes, directions, etc. shown in a particular figure. The various axes are described relative to each other so that the reader understands how one component is positioned relative to another component. For example, axes such as the X, Y, and Z axes can be easily replaced by a first axis, a second axis, and a third axis, and / or the coordinate system in a given figure can be easily rotated in one direction or another (e.g., so that certain components are then located on the Y axis instead of the X axis, etc.) without changing the described (multiple) systems themselves.

[0082] Figure 7 An exemplary metrology system 700 is shown having two sets of positioning elements and optical components 702 and 704 coupled to a central sensor 706, rather than as Figure 6 Two sensors are shown. Substrates 710 and 712 and corresponding wafer stages 714 and 716 are also shown. Figure 7 The central sensor 706 is shown in relation to two optical components, objective lens 719 and objective lens 721, formed using two Porro prisms 730 and 732 (e.g., a dual Porro prism system). Each objective lens 719 and 721 is configured to move in the X / Y direction relative to the central sensor 706. This is achieved using a dual Porro prism system, which is used for path length compensation, such as Figure 7 Directional flexible supports (e.g., XY-direction flexible supports 750 and 752 and Z-direction flexible supports 754 and 756) are used to reduce or prevent unwanted movement of objective lenses 719 and 721, respectively (e.g., unwanted XY movement when the objective lens moves in the Z direction, unwanted Z movement when the objective lens moves in the X or Y direction, etc.).

[0083] Figure 8 A mechanical system 800 is shown configured to achieve the desired motion of an objective lens 802 included in a metrology system. In the system 800, the motion of the dual porro prism 804 is coupled to the motion of the objective lens 802 by connectors 805, 807, 809 at approximately half the length of the XY flexible supports 810, 812, and 814. Figure 8 As shown, system 800 includes a Z actuator 820 connected in series to an XY actuator 830 to move objective lens 802 for focusing radiation on a substrate. Figure 8 Also shown are a substrate 850, a center sensor 860, a Z-flexure 870, and other components.

[0084] Fig. 9A positioning system 900 is shown for an optical element, such as a metrology device (e.g., Figure 3 The objective lens 950 of the system 10 shown in FIG. 1 is a system 10 of the embodiment of the present invention. The measurement device uses radiation to obtain information from the measurement target, and / or for other purposes. The radiation may include irradiation such as light and / or other radiation. For example, the target (e.g., the target 30 described above) may include one or more measurement marks formed in a substrate such as a semiconductor wafer, such as a diffraction grating target. The target may be one or more measurement marks, such as a diffraction grating target on a semiconductor wafer, as described herein, for example, the one or more measurement marks are collectively referred to as a single target. The target may include one or more structures in a patterned substrate that can provide a diffraction signal. For example, one or more targets may be included in a layer of a substrate in a semiconductor device structure. In some embodiments, the target includes geometric features such as 1D or 2D features and / or other geometric features. By way of several non-limiting examples, the target may include gratings, lines, edges, a series of lines and / or edges of fine pitch, and / or other features.

[0085] Positioning system 900 can form the above Figure 3 For example, positioning system 900 can be a subsystem of system 10. In some embodiments, one or more components of positioning system 900 can be similar to and / or identical to one or more components of system 10. In some embodiments, one or more components of positioning system 900 can replace one or more components of system 10, be used together with one or more components of system 10, and / or otherwise augment one or more components of system 10.

[0086] Positioning system 900 provides a comparison with existing systems (e.g., Figure 6 , 78). While the first dimension (e.g., Z direction) actuator is connected in series to the other dimension (e.g., XY) actuators to move the entire Porro prism and objective lens system to focus radiation on the target on the substrate, the system 900 uses the repositioned dimension (e.g., X, Y) actuators to provide three-dimensional (e.g., X, Y and Z) movement of the lighter objective lens stage, rather than mechanically coupling the movement of the Porro prism to the movement of the objective lens through a connection at half the length of a certain (e.g., XY direction) flexure. Positioning system 900 includes an objective stage 970, positioning devices such as positioning devices 902, 904 and / or 906, and / or other components. Positioning devices 902, 904 and / or 906 can be configured to move objective lens 950 (e.g., optical element) for, for example, overlay measurement. Overlay measurement can be for semiconductor wafers (e.g., substrates) and can be performed as part of a semiconductor manufacturing process (e.g., as described above).

[0087] Objective lens 950 (optical element) is supported by stage 970. Objective lens 950 may include one or more lenses formed of any transparent material having a curved surface configured to converge or otherwise focus one or more radiation spots onto (multiple) substrate targets (as described above). Stage 970 may support objective lens 950 by holding objective lens 950, coupling to objective lens 950, surrounding objective lens 950, and / or otherwise supporting objective lens 950. In some embodiments, objective lens 950 may be coupled to stage 970 via structural members, clips, clamps, screws, nuts, bolts, adhesives, and / or other mechanical devices. For example, as Fig. 9 As shown, stage 970 can have a rectangular prism shape (having a length, width, and thickness configured to be compatible with positioning system 900 and / or other components of metrology system 10) with a cylindrical aperture 967 at or near the center of a top surface 975 of stage 970. Aperture 967 is configured to receive and hold objective 950 such that a portion 951 of objective 950 is located on one side of stage 970 and a different portion 953 of objective 950 is located on an opposite side of stage 970. In some embodiments, objective 950 can, for example, be screwed into stage 970. Note that this is one possible embodiment of many ways that stage 970 can support objective 950.

[0088] In addition to objective lens 950, metrology system 10 may include (and stage 970 and / or other components may support) various lenses, reflectors, and other optical components that are configured to receive, transmit, reflect, focus, and / or perform other operations on radiation generated by a radiation source of metrology system 20, separated by a beam splitter, transmitted or reflected by other optical elements, and / or used by other portions of metrology system 10. These various lenses, reflectors, and / or other optical components may include any type of lenses, reflectors, and / or other optical components configured to allow system 10 and system 900 to function as described above. The various lenses, reflectors, optical elements, beam splitters, and / or other components may be positioned relative to each other at any position and / or at any angle that allows system 10 (including system 900) to function as described herein. This may include positioning at specific relative distances between elements, specific angles between elements, and the like. Fig. 9 The number of various lenses, reflectors, and / or other optical components shown in is not limiting. The principles described herein can be extended so that in some embodiments, system 900 includes additional or fewer lenses, reflectors, and / or other optical components.

[0089] The positioning device 902, 904 and / or 906 includes at least one flexible support (e.g., 910, 912, 914, 916, 918, 920, 922 as described below), a base (e.g., 930, 932, 934 as described below), a guide (e.g., 940, 942, 944 as described below) and / or other components connected to the object stage 970. At least one flexible support is configured to be relatively rigid in the axial direction of the positioning device and relatively flexible in other directions. The base is connected to the at least one flexible support. The base is configured to be actuated to move in the axial direction and thereby move the object stage 970. The guide is configured to connect the base to the frame of the measurement device. The guide is configured to bend when the base is actuated.

[0090] For example, Fig. 9As shown, the positioning system 900 includes a first positioning device 902, a second positioning device 904, and a third positioning device 906, which are connected to a stage 970 and are configured to move the stage 970 in a first direction 903 (e.g., X), a second direction 905 (e.g., Y), and a third direction 907 (e.g., Z), respectively. The first positioning device 902, the second positioning device 904, and the third positioning device 906 are configured to independently move the stage in the first direction 903 (X), the second direction 905 (Y), and the third direction 907 (Z) at different times and / or simultaneously to accurately position the objective lens 950 (optical element for measurement). In some embodiments, the connection between various components of each positioning device, the stage 970, and / or other components of the positioning system 900 is provided by structural members, clips, clamps, screws, nuts, bolts, adhesives, orifices, and / or other mechanical devices.

[0091] The first positioning device 902 includes a single flexible support member 910. The single flexible support member 910 is located at or near the center of the first side edge 971 of the stage 970. The second positioning device 904 includes two flexible supports 912 and 914. The two flexible supports 912 and 914 are located at opposite corners 921 and 923 (at the center of the second side edge 973 of the stage 970) of the stage 970. Fig. 9 The two flexible supports 912 and 914 are configured to reduce or prevent, for example, undesired rotation and / or other movement of the stage 970. The third positioning device 906 includes at least three flexible supports. Fig. 9 In the example shown, the third positioning device 906 includes flexible supports 916, 918, 920, and 922. The third positioning device 906 includes four flexible supports 916, 918, 920, and 922, and the four flexible supports 916, 918, 920, and 922 are located at four corresponding corners 917, 919, 921, and 923 of the stage 970 (in Fig. 9 The four flexible supports 916, 918, 920, and 922 are coupled to the top surface 975 of the stage 970 and are configured to reduce or prevent undesired rotation and / or tilting (and / or other movements) of the stage 970. The four flexible supports 916, 918, 920, and 922 of the third positioning device 906 are positioned around the porro prism 960 of the measurement device.

[0092] The flexible supports 910, 912, 914, 916, 918, 920, and 922 are configured to be relatively rigid in the axial direction (e.g., the first direction 903 (X), the second direction 905 (Y), or the third direction 907 (Z)) of the corresponding positioning device 902, 904, or 906, and relatively flexible in other directions. Fig. 9 As shown, the flexible supports 910, 912, 914, 916, 918, 920 and 922 can have an elongated body 991 in the corresponding axial direction. The elongated body 991 can have a square, rectangular, circular and / or other cross-sectional shape (the elongated body 991 is Fig. 9 The elongated body 991 provides a rigid axial connection between the stage 970 and other components of a given positioning device 902, 904, and / or 906. The rigid axial connection is configured to translate movement of the other components of a given positioning device to the stage 970.

[0093] Flexible supports 910, 912, 914, 916, 918, 920 and 922 also include one or more portions 993 with reduced cross-sections, which are configured to provide relative flexibility in non-axial directions. In some embodiments, one or more spherical ball bearings may be provided to facilitate similar behavior. This relative flexibility is configured to absorb, reduce, or prevent the undesirable movement of stage 970. For example, undesirable motion may include rotation along directions Rx, Ry, and / or Rz. Here, Rz is constrained by 912 and 914. Rx and Ry are constrained by the four vertical struts. Relative flexibility is configured to allow the desired XYZ motion in a direction perpendicular to the drive direction. For example, positioning device 904 provides Y motion, and supports 912 and 914 are flexible in X and Z directions to allow the motion.

[0094] In some embodiments, the flexible supports 910, 912, 914, 916, 918, 920, and 922 may be formed of metals, polymers, composite materials, and / or other materials. The relative stiffness in the axial direction and the flexibility in the non-axial direction may be provided at least in part by the material properties used to form the flexible supports 910, 912, 914, 916, 918, 920, and 922.

[0095] Bases 930, 932, and 934 are coupled to respective flexible supports for different positioning devices 902, 904, and 906. For example, in positioning device 902, base 930 is coupled to flexible support 910. In positioning device 904, base 932 is coupled to flexible supports 912, 914. In positioning device 906, base 934 is coupled to flexible supports 916, 918, 920, and 922. Bases 930, 932, and 934 are configured to be actuated to move along their respective axial directions (e.g., first direction 903 (X), second direction 905 (Y), or third direction 907 (Z)), and thereby move stage 970. In some embodiments, positioning devices 902, 904, 906 may include actuators coupled to bases 930, 932, 934, the actuators being configured to move the bases in an axial direction, and thereby move stage 970 and optical element (objective lens 950). Fig. 9 In the example shown, each base 930, 932, and 934 is shown as a rectangular surface configured to couple with such an actuator.Bases 930, 932, and 934 may have any shape and size that allows bases 930, 932, and 934 to function as described herein.

[0096] In some embodiments, one or more actuators ( Fig. 9 904 and / or 906 (and / or system 10) can be coupled to and configured to move one or more positioning devices 902, 904, and / or 906 of system 900. The actuators can be coupled to one or more components of positioning devices 902, 904, and / or 906 (and / or system 10) by adhesives, clips, clamps, screws, collars, and / or other mechanisms. The actuators can be configured to be controlled electronically. Individual actuators can be configured to convert electrical signals into mechanical displacements. The mechanical displacements are configured to move components of positioning devices 902, 904, and / or 906 as previously described. As an example, one or more of the actuators can be piezoelectric. One or more processors (see Figure 3 The PRO in the embodiment may be configured to control the actuator. One or more processors may be configured to individually control each of the one or more actuators.

[0097] For example, the movement can be configured to adjust the position of a corresponding radiation spot on one or more substrate targets. In some embodiments, the movement includes translating or otherwise changing the distance between various components of the system 900. In some embodiments, the movement can be electronically controlled by a processor, such as Figure 3 The processor PRO shown in (and discussed below) Fig.14 The processor PRO may be included in the computing system CS ( Fig.14 ) and can be based on computer or machine readable instructions MRI (e.g., as described below with respect to Fig.14 Electronic communication can be performed by transmitting electronic signals between separate components, transmitting data between separate components of system 900 and / or system 10, transmitting data from a lithographic apparatus (e.g., such as Figure 1 1 and / or 900. The components of system 10 and / or system 900 may communicate by wire or wirelessly via a network, such as the Internet or the Internet in combination with various other networks, such as a local area network, a cellular network, or a personal area network, an intra-organizational network, and / or other networks.

[0098] Note that in both system 900 and system 10, the motion of Porro prism 960 is provided by separate but similar components. Figure 8 The concept shown is different. Figure 8 In the prism, the prism is coupled to the stage of the objective, and the motion ratio is controlled by a linkage mechanism.

[0099] Guides 940, 942 and 944 are configured to connect bases 930, 932 and 934 to the frame of the measurement device (e.g., measurement system 10), respectively. For example, the frame can be the sensor frame of the measurement system 10. Different guides connect different bases to the same sensor frame. Guides 940, 942 and 944 are configured to bend when the corresponding bases 930, 932, 934 are actuated. In some embodiments, guides 940, 942, 944 include two parallel flexible plates located on opposite sides of the corresponding bases. For example, guide 940 includes parallel flexible plates 941 and 943. Plates 941 and 943 are connected to opposite sides of base 930 in positioning device 902. Plates 941 and 943 are configured to allow base 930 to move axially (as described above) when actuated without twisting, rotating or separating from the sensor frame. The guide 942 includes parallel flexible plates 945 and 947. The plates 945 and 947 are coupled to opposite sides of the base 932 in the positioning device 904. The plates 945 and 947 are configured to allow the base 932 to move axially when actuated (as described above) without twisting, rotating, or separating from the sensor frame. The guide 944 includes parallel flexible plates 949 and 955. In the positioning device 906, the plates 949 and 955 are coupled to opposite sides of the base 934. The plates 949 and 955 are configured to allow the base 934 to move axially when actuated (as described above) without twisting, rotating, or separating from the sensor frame.

[0100] In some embodiments, the parallel flexible plates can be formed from metals, polymers, composite materials, and / or other materials. The flexibility can be provided at least in part by the material properties used to form the parallel plates, the mechanical design of the parallel plates, the length, width, or thickness of the parallel plates, and / or other properties of the parallel plates. In some embodiments, a negative stiffness mechanism can be used to overcome the parasitic stiffness of the flexible support. Parasitic stiffness is the stiffness in the direction of motion that needs to be overcome by the actuator. Negative stiffness offsets parasitic stiffness, thereby reducing the force that needs to be applied by the actuator. The negative stiffness is not in the Fig. 9 Shown in , but can be added to the stage.

[0101] Fig.10 1 shows a metrology device, such as the system 10 described above, which includes a second positioning system 1000 (in addition to the positioning system 900). The second positioning system 1000 is configured to position a second objective lens 1050 so as to facilitate positioning on the same substrate ( Fig.10 Compared with the existing system, including two positioning systems in the measurement device to position the two objective lenses improves the utilization rate of the measurement device.

[0102] The pitch spacing can be defined as the distance from target to target within the substrate, which varies based on the customer design (e.g., small field: 22 mm, large field: 26 mm). The efficiency of the entire measurement system is improved by using objective lenses placed at a smaller pitch spacing. In some embodiments, the second positioning system 1000 is configured so that the distance D from the objective lens 1050 to the objective lens 950 in the measurement device is equal to or less than the target distance. For example, the distance D can be less than or equal to about 60 mm. In some embodiments, the distance D can be less than or equal to about 48 mm. In some embodiments, the distance D can be less than or equal to about 45 mm. In some embodiments, the distance D can be between 44 mm and 52 mm. Note that in some embodiments, the system components as described above can be oriented in the y direction of the system (as described above, the system components as described above are oriented in the x direction). In this orientation, the maximum field size can be about 33 mm and the minimum field size can be about 28 mm, but this is only an example and larger or smaller field sizes can also be configured.

[0103] like Fig.10 As shown, the components of the second positioning system 1000 correspond to the components of the positioning system 900. By way of several examples, Fig.10 The positioning devices 1002, 1004 and 1006 are shown; flexible supports 1012 and 1014; stage 1070; objective lens 1050; bases 1030, 1032 and 1034; and guides 1040, 1042, 1044 (note that due to Fig.10The size and perspective of the image obscure some parts from a clear view, so Fig.10 Each corresponding component is not shown).

[0104] Fig.11 A metrology apparatus such as the system 10 described above is shown, the system 10 comprising, in addition to the second positioning system 1000 and the positioning system 900, a third positioning system 1100 and a fourth positioning system 1102. For example, the third positioning system 1100 and the fourth positioning system 1102 are configured to position a third objective lens 1150 and a fourth objective lens 1152, respectively, to facilitate simultaneous measurement of, for example, different substrates 1060 and 1062 (supported by substrate tables WT1 and WT2). Fig.11 Also shown is the sensor frame 1151 (shown in cross section). As described above, guide members 940, 942 and 944 ( Fig. 9 ) and the corresponding guide members of the positioning systems 1000, 1100 and 1102 are configured to position the bases 930, 932 and 934 ( Fig. 9 ) and the corresponding bases of the positioning systems 1000, 1100 and 1102 are respectively connected to the frame 1151.

[0105] Fig.12 Provided Fig.11 In addition to the second positioning system 1000 and the positioning system 900, Fig.11 Also shown are a third positioning system 1100 and a fourth positioning system 1102. Also shown are the first objective 950, the second objective 1050, the third objective 1150 and the fourth objective 1152, respectively, as well as the substrates 1060 and 1062, and the substrate tables WT1 and WT2. Note that the light from the four objectives comes from and reaches a central sensor located in the metrology frame (but not visible in this figure).

[0106] Fig.13 A (portion of) a metrology apparatus is shown having a prism assembly 1300 (eg, a dual Porro prism as described above) and an objective lens 1302 and corresponding prism positioning systems 1304 and objective lens positioning systems 1306. Fig.13 The objective lens positioning system 1306 shown may have, for example, Fig. 9 Some and / or all of the same components (or similar components) as the system 900 shown. Fig.13, the objective lens positioning system 1306 includes an objective lens stage 1308 configured to support the objective lens 1302; and a first objective lens positioning device 1310, a second objective lens positioning device 1312, and a third objective lens positioning device 1314, which are connected to the objective lens stage and are configured to move the objective lens stage in the X direction, the Y direction, and the Z direction, respectively. The objective lens positioning devices 1310, 1312, and / or 1324 include at least one flexible objective lens support 1318, 1320, 1322, 1324, 1326, 1328, and / or 1330 connected to the stage 1308. At least one flexible objective lens support 1318 to 1330 is configured to be relatively rigid in the axial direction of the objective lens positioning device and relatively flexible in other directions. The objective lens positioning devices 1310 to 1314 include respective objective lens bases 1332, 1334 and / or 1336 coupled to at least one flexible objective lens support 1318 to 1330. The objective lens bases 1332 to 1336 are configured to be actuated to move in an axial direction (for the positioning device) and in turn move the objective lens stage 1308 and the objective lens 1302 to direct radiation toward a target on a substrate. The objective lens positioning devices 1310 to 1314 include respective objective lens guides 1338, 1340 ( Fig.13 ), 1342, objective lens guides 1338, 1340, 1342 are configured to connect the objective lens bases 1332 to 1336 to the frame of the measurement device ( Fig.13 ). The objective lens guides 1338 to 1342 are configured to flex when the corresponding objective lens base 1332 to 1336 is actuated, but remain coupled to the frame.

[0107] The prism positioning system 1304 includes a prism stage 1350 configured to support the prism assembly 1300. A first prism positioning device 1352 and a second prism positioning device 1354 are coupled to the prism stage 1350 and are configured to move the prism stage 1350 in the X direction and the Y direction, respectively. The prism positioning devices 1352 and / or 1354 include at least one flexible prism support 1356, 1358, 1360 coupled to the prism stage 1350. The at least one flexible prism support 1356 to 1360 is configured to be relatively rigid in the axial direction of the prism positioning device 1310 or 1312 and relatively flexible in other directions. The prism positioning devices 1352 and / or 1354 include a prism base 1362, 1364 coupled to the at least one flexible prism support 1356 to 1360. The prism base 1362 and / or 1364 is configured to be actuated to move the positioning device in an axial direction, and in turn move the prism stage 1350 and the prism assembly 1300 to direct radiation toward a target on the substrate. The prism positioning device 1352 and / or 1354 includes a prism guide 1370 and / or 1372 ( configured to couple the prism base 1362 and / or 1364 to the frame of the metrology device. Fig.13 ). The prism guides 1370 and / or 1372 are configured to flex when the corresponding prism base 1362, 1364 is actuated, but remain coupled to the frame.

[0108] In some embodiments, the first objective lens positioning device 1310, the second objective lens positioning device 1312, and the third objective lens positioning device 1314 are configured to move the objective lens stage 1308 in the X direction, the Y direction, and the Z direction; and the first prism positioning device 1352 and the second prism positioning device 1354 are configured to independently move the prism stage 1350 in the X direction and the Y direction at different times and / or simultaneously to accurately position the objective lens 1302 and / or the prism member 1300 for measurement. In some embodiments, the first (X direction) prism positioning device 1352 includes a single flexible support 1356, and the second (Y direction) prism positioning device 1354 includes two flexible supports 1358 and 1360. The two flexible supports 1358 and 1360 of the second prism positioning device 1354 can be, for example, located at or near opposite corners of a first side edge of the prism stage 1350, and the single flexible support 1356 of the first prism positioning device 1352 can be located at or near the center of the second side edge of the prism stage 1350 (e.g., according to Fig.131354). In some embodiments, the two flexible supports 1358 and 1360 of the second prism positioning device 1354 include parallel rectangular plates, and the single flexible support 1356 of the first prism positioning device 1352 includes an elongated body having a square or rectangular cross-section, but these are only some examples of many possible configurations of supports 1356, 1358 and / or 1360.

[0109] In some embodiments, the voice coil and / or other actuators (e.g., Fig.13 1375 shown in ), an optical encoder (e.g., Fig.13 1377) and / or other components shown in the figure can be convenient for Fig.13 (or any other figure) actuation of one or more positioning devices shown in FIG.

[0110] Fig.14 A measurement method 1400 is shown. Some or all of the method 1400 may be performed using a measurement device, such as a Figure 3 The measurement (inspection) system 10 shown in and described above, the positioning system described above, the computer system (e.g., Fig.15 and / or other systems shown in and described below. In some embodiments, for example, method 1400 is performed as part of an overlay and / or alignment sensing operation in a semiconductor device manufacturing process. In some embodiments, method 1400 includes generating (operation 1402) radiation, supporting (operation 1404) an optical component such as an objective lens using a stage of a metrology device, moving (operation 1406) the stage using a first positioning device, a second positioning device, and a third positioning device of a first positioning system of the metrology device, coupling (operation 1408) at least one flexible support to the stage, coupling (operation 1410) a base to at least one flexible support, coupling (operation 1412) the base to a frame of the metrology device, and receiving (operation 1414) radiation diffracted and reflected from a target using a detector and generating a detection signal and / or other operations.

[0111] The operations of method 1400 are intended to be illustrative. In some embodiments, method 1400 may utilize one or more additional operations not described and / or be accomplished without one or more of the operations discussed. For example, in some embodiments, method 1400 may include additional operations including determining adjustments to a semiconductor device manufacturing process. As another example, method 1400 may include using Fig.13 The device shown positions the double porro prism and combines the corresponding operation of positioning the objective lens. Note that Fig.14 The order in which the operations of method 1400 are illustrated and described herein is not intended to be limiting.

[0112] In some embodiments, one or more portions of method 1400 may be implemented in and / or controlled by one or more processing devices (e.g., a digital processor, an analog processor, a digital circuit designed to process information, an analog circuit designed to process information, a state machine, and / or other mechanism for electronically processing information). The one or more processing devices may include one or more devices that perform some or all of the operations of method 1400 in response to instructions stored electronically on an electronic storage medium. The one or more processing devices may include one or more devices configured by hardware, firmware, and / or software that are specifically designed to perform one or more of the operations of method 1400 (e.g., see below regarding Fig.15 for discussion).

[0113] At operation 1402, radiation is generated using a radiation source of a metrology device and directed along an optical path toward a prismatic component and an objective lens. In some embodiments, operation 1402 includes illuminating (and / or otherwise irradiating) one or more targets (e.g., Figure 3 The radiation may be provided by a radiation source (e.g., Figure 3 2). In some embodiments, radiation can be directed by a radiation source onto multiple targets, a single target, a sub-portion of a target (e.g., a portion that is smaller than the whole), and / or onto a substrate in other ways. In some embodiments, radiation can be directed by a radiation source onto a target in a time-varying manner. For example, the radiation can be rasterized on the target (e.g., by moving the target under the radiation) so that different portions of the target are irradiated at different times. As another example, the characteristics of the radiation (e.g., wavelength, intensity, etc.) can vary. This can create a time-varying data envelope or window for analysis. The data envelope can facilitate analysis of separate sub-portions of a target, comparison of one portion of a target with another portion and / or with other targets (e.g., in other layers), and / or other analysis.

[0114] In some embodiments, the prism component is a Porro prism such as the Porro prism 960 described above and / or other prism components. In some embodiments, the objective lens is similar to and / or the same as the objective lens 950 and / or other objective lenses described above. In some embodiments, operation 1402 includes providing a radiation source (e.g., Figure 3 Source shown in 2).

[0115] At operation 1404, the objective lens is supported using a stage of the metrology apparatus. The stage may be similar and / or the same as stage 970 and / or other stages described above.

[0116] At operation 1406, the first positioning device, the second positioning device and the third positioning device of the first positioning system of the measuring device are used to move the stage. The first positioning device, the second positioning device and the third positioning device are connected to the stage and are configured to move the stage in the X direction, the Y direction and the Z direction respectively. The first positioning device, the second positioning device and the third positioning device are configured to independently move the stage in the X direction, the Y direction and the Z direction at different times and / or simultaneously, so as to accurately position the object lens for measurement. The positioning system can be similar to the above-mentioned positioning system 900 and / or other positioning systems and / or be identical with the above-mentioned positioning system 900 and / or other positioning systems. The first positioning device, the second positioning device and the third positioning device can be similar and / or identical with the above-mentioned positioning devices 902,904 and 906 and / or other positioning devices.

[0117] In some embodiments, operation 1406 includes positioning the second objective lens using a second positioning system to facilitate two simultaneous measurements on the same substrate (see above regarding Fig.10 In some embodiments, the second positioning system is configured such that the distance from one objective lens to another objective lens in the metrology apparatus is about 48 mm. In some embodiments, operation 1406 includes positioning the third objective lens and the fourth objective lens using the third positioning system and the fourth positioning system, respectively, to facilitate two additional simultaneous measurements by the metrology apparatus on the second substrate (see the discussion above). Fig.11 Related discussion).

[0118] At operation 1408, at least one flexible support is coupled to the stage. The at least one flexible support is configured to be relatively rigid in the axial direction of the positioning device and relatively flexible in other directions. The at least one flexible support can be similar and / or identical to any of the flexible supports 910 to 922 and / or other flexible supports described above.

[0119] In some embodiments, the first positioning device includes a single flexible support, the second positioning device includes two flexible supports, and the third positioning device includes four flexible supports. In some embodiments, the single flexible support of the first positioning device is located at the center of the first side edge of the stage or near the center of the first side edge of the stage. The two flexible supports of the second positioning device can be located at the relative corners of the second side edge of the stage or near the relative corners of the second side edge of the stage. The two flexible supports are configured to reduce or prevent undesirable rotation of the stage. The four flexible supports of the third positioning device can be connected to the top surface of the stage and are configured to reduce or prevent, for example, undesirable rotation and / or tilting of the stage. The four flexible supports of the third positioning device can be positioned around a prismatic component (e.g., a porro prism) of a measurement device.

[0120] At operation 1410, a pedestal is coupled to at least one flexible support. The pedestal is configured to be actuated to move in an axial direction and, in turn, to move the stage and objective lens to direct radiation toward a target on a substrate. The pedestal may be similar and / or identical to any of the pedestals 930 to 934 described above and / or other pedestals.

[0121] At operation 1412, the base is connected to the frame of the measuring device by a guide. The guide is configured to bend when the base is actuated, but remains connected to the frame. In some embodiments, the guide includes two parallel flexible plates positioned on opposite sides of the base. The guide can be similar and / or identical to any one of the guides 940 to 944 and / or other guides described above.

[0122] At operation 1414, diffracted and reflected radiation from the target is received with a detector, and a detection signal is generated. In some embodiments, operation 1414 includes detecting reflected radiation from one or more diffraction grating targets. Detecting the reflected radiation includes detecting one or more phase and / or amplitude (intensity) shifts in the reflected radiation from one or more geometric features of the target(s). The one or more phase and / or amplitude shifts correspond to one or more dimensions of the target. For example, the phase and / or amplitude of the reflected radiation from one side of the target is different relative to the phase and / or amplitude of the reflected radiation from the other side of the target.

[0123] Detecting one or more phase and / or amplitude (intensity) shifts in reflected radiation from a target includes measuring local phase shifts (e.g., local phase increments) and / or amplitude changes corresponding to different parts of the target. For example, reflected radiation from a specific area of ​​the target may include a sinusoidal waveform with a specific phase and / or amplitude. Reflected radiation from different areas of the target (or targets in different layers) may also include sinusoidal waveforms, but the sinusoidal waveforms have different phases and / or amplitudes. The detected reflected radiation also includes measuring phase and / or amplitude differences in reflected radiation of different diffraction orders. For example, Hilbert transforms and / or other techniques can be used to perform detection of one or more local phase and / or amplitude shifts. Interferometric measurement techniques and / or other operations can be used to measure phase and / or amplitude differences in reflected radiation of different diffraction orders.

[0124] In some embodiments, generating the detection signal includes generating a measurement signal based on the detected reflected radiation from the diffraction grating target(s), as described above. Figure 3 The detector 4, camera and / or other sensor in the apparatus generates a measurement signal based on the radiation received by the sensor. The measurement signal includes measurement information about the target(s). For example, the measurement signal may be an overlap and / or alignment signal including overlap and / or alignment measurement information, and / or other measurement signals. The measurement information (e.g., overlap value, alignment value and / or other information) may be determined using interferometry principles and / or other principles.

[0125] The measurement signal includes an electronic signal representing and / or otherwise corresponding to radiation reflected from the target(s). The measurement signal may indicate, for example, a measurement value and / or other information associated with a diffraction grating target. Generating the measurement signal includes sensing the reflected radiation and converting the sensed reflected radiation into the electronic signal. In some embodiments, generating the measurement signal includes sensing different portions of the reflected radiation from different regions and / or different geometries of the target and / or multiple targets, and combining the different portions of the reflected radiation to form the measurement signal. This may include generating and / or analyzing one or more images of the target using the radiation described herein. The sensing and conversion may be performed by a computer program product associated with the computer program product. Figure 3 The detector 4 and / or the processor PRO shown in FIG. 4 may be implemented using similar and / or identical components and / or other components.

[0126] Operation 1414 may include determining overlap and / or alignment. Overlap and / or alignment may be determined based on, for example, reflected diffracted radiation from a diffraction grating target and / or based on other information. In some embodiments, operation 1414 is performed by Figure 3 The detector 4 and processor PRO shown and described above may be the same or similar detectors and / or other detectors implemented.

[0127] In some embodiments, method 1400 includes one or more additional operations, such as determining adjustments for a semiconductor device manufacturing process. In some embodiments, method 1400 includes determining one or more semiconductor device manufacturing process parameters. The one or more semiconductor device manufacturing process parameters can be determined based on one or more detected phase and / or amplitude changes, overlap and / or alignment values ​​indicated by the measurement signal, and / or other similar systems and / or other information. The one or more parameters may include parameters of radiation (radiation for measurement), overlap values, alignment values, measurement inspection positions on layers of semiconductor device structures, radiation beam trajectories across targets, and / or other parameters. In some embodiments, process parameters may be broadly interpreted as including (measurement and / or wafer) stage positions, mask designs, measurement target designs, semiconductor device designs, radiation intensity (for exposure resists, etc.), radiation incident angles (for exposure resists, etc.), radiation wavelengths (for exposure resists, etc.), pupil sizes and / or shapes, resist materials, and / or other parameters.

[0128] In some embodiments, method 1400 includes determining a process adjustment based on one or more determined semiconductor device manufacturing process parameters, adjusting semiconductor device manufacturing equipment based on the determined adjustment, and / or other operations. For example, if the determined metrology measurement result is not within the process tolerance, then the measurement result outside the tolerance may be caused by one or more manufacturing processes where the process parameters have drifted and / or otherwise changed so that the process no longer produces acceptable devices (e.g., the measurement may exceed a threshold of acceptability). One or more new or adjusted process parameters may be determined based on the measurement result. The new or adjusted process parameters may be configured to cause the manufacturing process to produce acceptable devices again.

[0129] For example, a new or adjusted process parameter may cause a previously unacceptable measurement to be adjusted back into an acceptable range. The new or adjusted process parameter may be compared to the existing parameters for a given process. For example, if there is a difference, the difference may be used to determine an adjustment to an apparatus used to produce the device (e.g., parameter "x" should be increased / decreased / changed so that parameter "x" matches a new or adjusted version of parameter "x" determined as part of method 1400). In some embodiments, method 1300 may include electronically adjusting the apparatus (e.g., based on the determined process parameter). Electronically adjusting the apparatus may include sending an electronic signal and / or other communication to the apparatus, for example, which causes a change in the apparatus. Electronically adjusting may include, for example, changing settings on the apparatus and / or other adjustment methods.

[0130] Fig.151 is a diagram of an exemplary computer system CS that can be used for one or more operations described herein. The computer system CS includes a bus BS or other communication mechanism for transmitting information, and a processor PRO (or processors) coupled to the bus BS for processing information. Figure 3 The computer system CS further comprises a main memory MM, such as a random access memory (RAM) or other dynamic storage device, which is connected to the bus BS for storing information and instructions to be executed by the processor PRO. The main memory MM can also be used to store temporary variables or other intermediate information during the execution of instructions by the processor PRO. The computer system CS further comprises a read-only memory (ROM) ROM or other static storage device, which is connected to the bus BS for storing static information and instructions of the processor PRO. A storage device SD, such as a magnetic disk or optical disk, is provided, which is connected to the bus BS for storing information and instructions.

[0131] The computer system CS can be connected to a display DS via a bus BS, such as a flat panel or touch panel display or a cathode ray tube (CRT), for displaying information to a computer user. An input device ID including alphanumeric keys and other keys is connected to the bus BS for transmitting information and command selections to the processor PRO. Another type of user input device is a cursor control CC, such as a mouse, a trackball, or cursor direction keys, for transmitting direction information and command selections to the processor PRO, and for controlling the movement of the cursor on the display DS. The input device typically has two degrees of freedom on two axes (a first axis (e.g., x) and a second axis (e.g., y)), which allows the device to specify a position in a plane. A touch panel (screen) display can also be used as an input device.

[0132] In some embodiments, all or some of one or more operations described herein (e.g., controlling an actuator to move a stage, controlling a measuring device, analyzing sensor data, etc.) can be performed by a computer system CS in response to a processor PRO executing one or more sequences of one or more instructions contained in a main memory MM. These instructions can be read into the main memory MM from another computer-readable medium such as a storage device SD. The sequence of instructions included in the main memory MM is executed so that the processor PRO performs the processing steps (operations) described herein. One or more processors in a multiprocessing device can also be used to execute the sequence of instructions contained in the main memory MM. In some embodiments, a hard-wired circuit can be used to replace a software instruction or to combine with a software instruction. Therefore, the description herein is not limited to any specific combination of hardware circuits and software.

[0133] As used herein, the term "computer-readable medium" or "machine-readable medium" refers to any medium that participates in providing instructions to the processor PRO for execution. This medium can take many forms, including but not limited to non-volatile media, volatile media and transmission media. For example, non-volatile media include optical disks or disks, such as storage devices SD. Volatile media include dynamic memory, such as main memory MM. Transmission media include coaxial cables, copper wires and optical fibers, including wires containing bus BS. Transmission media can also take the form of sound waves or light waves, such as those generated during radio frequency (RF) and infrared (IR) data communication. Computer-readable media can be non-temporary, such as floppy disks, flexible disks, hard disks, magnetic tapes, any other magnetic media, CD-ROMs, DVDs, any other optical media, punch cards, paper tapes, any other physical media with hole patterns, RAMs, PROMs and EPROMs, FLASH-EPROMs, any other memory chips or cassettes. Non-temporary computer-readable media can have instructions recorded thereon. When executed by a computer, instructions can implement any operation described herein. For example, transitory computer readable media may include carrier waves or other propagated electromagnetic signals.

[0134] Various forms of computer-readable media can be used to transmit one or more sequences of one or more instructions to the processor PRO for execution. For example, the instructions may initially be carried on a disk of a remote computer. The remote computer may load the instructions into its dynamic memory and send the instructions via a telephone line using a modem. The modem local to the computer system CS may receive data on the telephone line and convert the data into infrared signals using an infrared transmitter. An infrared detector connected to the bus BS may receive the data carried in the infrared signal and place the data on the bus BS. The bus BS transmits the data to the main memory MM, from which the processor PRO retrieves and executes the instructions. The instructions received by the main memory MM may optionally be stored on a storage device SD before or after being executed by the processor PRO.

[0135] The computer system CS may also include a communication interface CI connected to the bus BS. The communication interface CI provides a bidirectional data communication connection with a network link NDL connected to the local area network LAN. For example, the communication interface CI may be an integrated services digital network (ISDN) card or a modem to provide a data communication connection to a telephone line of a corresponding type. As another example, the communication interface CI may be a local area network (LAN) card to provide a data communication connection to a compatible LAN. A wireless link may also be implemented. In any such implementation, the communication interface CI sends and receives electrical signals, electromagnetic signals, or optical signals carrying digital data streams representing various types of information.

[0136] The network link NDL usually provides data communication to other data devices through one or more networks. For example, the network link NDL can provide a connection to the host computer HC through a local network LAN. This can include data communication services provided by a global packet data communication network, which is now generally referred to as the "Internet" INT. The local area network LAN (Internet) can use electrical signals, electromagnetic signals, or optical signals carrying digital data streams. Signals through various networks and signals on the network data link NDL and signals through the communication interface CI that carry digital data to and from the computer system CS are exemplary forms of carrier waves that transmit information.

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

[0138] Various embodiments of the present system and method are disclosed in the list of numbered aspects that follow. Below, additional features, characteristics, and exemplary technical solutions of the present disclosure will be described according to aspects that can be optionally claimed in any combination:

[0139] 1. A positioning system for an optical element of a measuring device, the positioning system comprising: a stage; and a positioning device, the positioning device comprising: at least one flexible support member, the at least one flexible support member is connected to the stage, the at least one flexible support member is configured to be relatively rigid in the axial direction of the positioning device and relatively flexible in other directions; a base, the base is connected to the at least one flexible support member, the base is configured to be actuated to move in the axial direction and in turn move the stage; and a guide member, the guide member is configured to connect the base to the frame of the measuring device, the guide member is configured to bend when the base is actuated.

[0140] 2. A system according to aspect 1, wherein the positioning system includes a first positioning device, a second positioning device and a third positioning device, and the first positioning device, the second positioning device and the third positioning device are connected to the worktable and are configured to move the worktable in the X direction, the Y direction and the Z direction respectively.

[0141] 3. A system according to any one of the preceding aspects, wherein the first positioning device, the second positioning device and the third positioning device are configured to independently move the stage in the X direction, the Y direction and the Z direction at different times and / or simultaneously to accurately position the optical element for measurement, the optical element being supported by the stage.

[0142] 4. The system according to any of the preceding aspects, wherein the first positioning device comprises a single flexible support, the second positioning device comprises two flexible supports, and the third positioning device comprises at least three flexible supports.

[0143] 5. The system according to any one of the preceding aspects, wherein the third positioning device comprises four flexible supports positioned at or near four corresponding corners of the stage.

[0144] 6. The system of any of the preceding aspects, wherein the single flexible support of the first positioning device is located at or near the center of a first side edge of the stage.

[0145] 7. A system according to any one of the preceding aspects, wherein the two flexible supports of the second positioning device are located at or near opposite corners of the second side edge of the worktable, and the two flexible supports are configured to reduce or prevent unwanted rotation of the worktable.

[0146] 8. A system according to any of the preceding aspects, wherein the four flexible supports of the third positioning device are connected to the top surface of the worktable and are configured to reduce or prevent undesired rotation and / or tilting of the worktable.

[0147] 9. The system according to any of the preceding aspects, wherein the four flexible supports of the third positioning device are positioned around a Porro prism of the metrology device.

[0148] 10. A system according to any of the preceding aspects, wherein the optical element is an objective lens.

[0149] 11. A system according to any of the preceding aspects, wherein the guide comprises two parallel flexible plates positioned on opposite sides of the base.

[0150] 12. The system according to any of the preceding aspects, wherein the frame is a sensor frame of the measurement device.

[0151] 13. The system according to any of the preceding aspects, wherein the positioning device is configured to move the optical element for overlay measurement.

[0152] 14. The system according to any of the preceding aspects, wherein the overlay measurement is for a semiconductor wafer and is performed as part of a semiconductor manufacturing process.

[0153] 15. The system according to any one of the preceding aspects, the positioning device further comprising an actuator coupled to the base, the actuator being configured to move the base in the axial direction and in turn move the stage and the optical element.

[0154] 16. A measurement device, comprising: a radiation source, the radiation source being configured to generate radiation directed along an optical path toward a prism component and an objective lens; a positioning system for the objective lens, the positioning system comprising: a stage, the stage being configured to support the objective lens; and a first positioning device, a second positioning device, and a third positioning device, the first positioning device, the second positioning device, and the third positioning device being coupled to the stage and configured to move the stage in an X direction, a Y direction, and a Z direction, respectively; a positioning device, the positioning device comprising: at least one flexible support, the at least one flexible support being coupled to the stage, the at least one flexible support The at least one flexible support member is configured to be relatively rigid in the axial direction of the positioning device and relatively flexible in other directions; a base, the base is connected to the at least one flexible support member, the base is configured to be actuated to move in the axial direction, and in turn moves the stage and the objective lens to guide the radiation toward the target on the substrate; and a guide member, the guide member is configured to couple the base to the frame of the measurement device, the guide member is configured to bend when the base is actuated, but remain connected to the frame; and a detector, the detector is configured to receive diffracted and reflected radiation from the target and generate a detection signal.

[0155] 17. The metrology apparatus of clause 16, further comprising a second positioning system configured to position the second objective lens to facilitate two simultaneous measurements on the same substrate.

[0156] 18. A metrology apparatus according to any one of the preceding aspects, wherein the second positioning system is configured such that a distance from one objective lens to another objective lens in the metrology device is approximately 48 mm.

[0157] 19. The measurement device according to any one of the preceding aspects further includes a third positioning system and a fourth positioning system, wherein the third positioning system and the fourth positioning system are configured to position the third objective lens and the fourth objective lens, respectively, so as to facilitate two additional simultaneous measurements to be performed on the second substrate by the measurement device.

[0158] 20. A measurement device according to any one of the preceding aspects, wherein the first positioning device, the second positioning device and the third positioning device are configured to independently move the stage in the X direction, the Y direction and the Z direction at different times and / or simultaneously to accurately position the objective lens for measurement.

[0159] 21. The metrology apparatus according to any of the preceding aspects, wherein the first positioning device comprises a single flexible support, the second positioning device comprises two flexible supports, and the third positioning device comprises four flexible supports.

[0160] 22. A measuring device according to any one of the preceding aspects, wherein the single flexible support member of the first positioning device is located at the center of the first side edge of the worktable or near the center of the first side edge of the worktable; the two flexible supports of the second positioning device are located at opposite corners of the second side edge of the worktable or near opposite corners of the second side edge of the worktable, and the two flexible supports are configured to reduce or prevent unwanted rotation of the worktable; and the four flexible supports of the third positioning device are connected to the top surface of the worktable and are configured to reduce or prevent unwanted rotation and / or tilting of the worktable.

[0161] 23. The metrology apparatus according to any one of the preceding aspects, wherein the four flexible supports of the third positioning device are positioned around the prismatic component of the metrology device.

[0162] 24. A metrology apparatus according to any one of the preceding aspects, wherein the guide comprises two parallel flexible plates positioned on opposite sides of the base.

[0163] 25. The metrology apparatus according to any of the preceding aspects, wherein the metrology device is configured for overlay measurement of semiconductor wafers and is made part of a semiconductor manufacturing process.

[0164] 26. A method for positioning an optical element of a measuring device, the method comprising: supporting the optical element with a stage; connecting at least one flexible support member of a positioning device to the stage, the at least one flexible support member being configured to be relatively rigid in an axial direction of the positioning device and relatively flexible in other directions; connecting a base of the positioning device to the at least one flexible support member, the base being configured to be actuated to move in the axial direction and, in turn, move the stage; connecting the base to a frame of the measuring device using a guide member of the positioning device, the guide member being configured to bend when the base is actuated; and actuating the base to move in the axial direction, thereby moving the stage and positioning the optical element.

[0165] 27. The method according to aspect 26, wherein the positioning system includes a first positioning device, a second positioning device and a third positioning device, wherein the first positioning device, the second positioning device and the third positioning device are connected to the worktable and configured to move the worktable in the X direction, the Y direction and the Z direction respectively.

[0166] 28. A method according to any one of the preceding aspects, wherein the first positioning device, the second positioning device and the third positioning device are configured to independently move the stage in the X direction, the Y direction and the Z direction at different times and / or simultaneously so as to accurately position the optical element for measurement, the optical element being supported by the stage.

[0167] 29. The method according to any of the preceding aspects, wherein the first positioning device comprises a single flexible support, the second positioning device comprises two flexible supports, and the third positioning device comprises at least three flexible supports.

[0168] 30. A method according to any one of the preceding aspects, wherein the third positioning device comprises four flexible supports positioned at or near four corresponding corners of the worktable.

[0169] 31. A method according to any of the preceding aspects, wherein the single flexible support member of the first positioning device is located at or near the center of the first side edge of the worktable.

[0170] 32. A method according to any one of the preceding aspects, wherein the two flexible supports of the second positioning device are located at or near the second side edge of the worktable, and the two flexible supports are configured to reduce or prevent unwanted rotation of the worktable.

[0171] 33. A method according to any of the preceding aspects, wherein the four flexible supports of the third positioning device are connected to the top surface of the worktable and are configured to reduce or prevent undesired rotation and / or tilting of the worktable.

[0172] 34. The method according to any of the preceding aspects, wherein the four flexible supports of the third positioning device are positioned around a Porro prism of the metrology device.

[0173] 35. A method according to any of the preceding aspects, wherein the optical element is an objective lens.

[0174] 36. A method according to any of the preceding aspects, wherein the guide comprises two parallel flexible plates positioned on opposite sides of the base.

[0175] 37. A method according to any of the preceding aspects, wherein the frame is a sensor frame of the measurement device.

[0176] 38. The method according to any of the preceding aspects, further comprising moving the optical element with the positioning device for overlay measurement.

[0177] 39. The method according to any of the preceding clauses, wherein the overlay measurement is of a semiconductor wafer and is performed as part of a semiconductor manufacturing process.

[0178] 40. The method according to any of the preceding aspects, the positioning device further comprising an actuator coupled to the base, the actuator being configured to move the base in an axial direction and thereby move the stage and the optical element.

[0179] 41. A method performed using a measurement device, the method comprising: using a radiation source of the measurement device to generate radiation directed along an optical path toward a prism component and an objective lens; using a stage of the measurement device to support the objective lens; using a first positioning device, a second positioning device, and a third positioning device of a first positioning system of the measurement device to move the stage, the first positioning device, the second positioning device, and the third positioning device being connected to the stage and configured to move the stage in an X direction, a Y direction, and a Z direction, respectively; connecting at least one flexible support member to the stage, the at least one flexible support member A flexible support is configured to be relatively rigid in an axial direction of the positioning device and relatively flexible in other directions; a base is connected to at least one of the flexible supports, the base is configured to be actuated to move in the axial direction, and thereby move the stage and the objective lens to direct the radiation toward a target on the substrate; the base is connected to a frame of the measurement device using a guide, the guide is configured to bend when the base is actuated but remain connected to the frame; and a detector is used to receive diffracted and reflected radiation from the target and generate a detection signal.

[0180] 42. The method of clause 41, further comprising positioning the second objective lens using a second positioning system to facilitate two simultaneous measurements on the same substrate.

[0181] 43. A method according to any of the preceding aspects, wherein the second positioning system is configured so that the distance from one objective lens to another objective lens in the measurement device is approximately 48 mm.

[0182] 44. The method according to any of the preceding aspects further comprises positioning a third objective lens and a fourth objective lens using a third positioning system and a fourth positioning system, respectively, to facilitate two additional simultaneous measurements by the metrology device on a second substrate.

[0183] 45. A method according to any one of the preceding aspects, wherein the first positioning device, the second positioning device and the third positioning device are configured to independently move the stage in the X direction, the Y direction and the Z direction at different times and / or simultaneously to accurately position the objective lens for measurement.

[0184] 46. ​​The method according to any of the preceding aspects, wherein the first positioning device comprises a single flexible support, the second positioning device comprises two flexible supports, and the third positioning device comprises four flexible supports.

[0185] 47. A method according to any one of the preceding aspects, wherein the single flexible support member of the first positioning device is located at the center of the first side edge of the worktable or near the center of the first side edge of the worktable; the two flexible supports of the second positioning device are located at opposite corners of the second side edge of the worktable or near opposite corners of the second side edge of the worktable, and the two flexible supports are configured to reduce or prevent unwanted rotation of the worktable; and the four flexible supports of the third positioning device are connected to the top surface of the worktable and are configured to reduce or prevent unwanted rotation and / or tilting of the worktable.

[0186] 48. A method according to any of the preceding aspects, wherein the four flexible supports of the third positioning device are positioned around the prismatic component of the measurement device.

[0187] 49. A method according to any of the preceding aspects, wherein the guide member comprises two parallel flexible plates positioned on opposite sides of the base.

[0188] 50. The method according to any of the preceding clauses, wherein the metrology equipment is configured for overlay measurement of semiconductor wafers and is performed as part of a semiconductor manufacturing process.

[0189] 51. A measuring device having a prism component and an objective lens, the measuring device comprising: an objective lens positioning system, the objective lens positioning system comprising: an objective lens stage, the objective lens stage being configured to support the objective lens; and a first objective lens positioning device, a second objective lens positioning device and a third objective lens positioning device, the first objective lens positioning device, the second objective lens positioning device and the third objective lens positioning device being connected to the objective lens stage and configured to move the objective lens stage in the X direction, the Y direction and the Z direction respectively, the objective lens positioning device comprising: at least one flexible objective lens support, the at least one flexible objective lens support being connected to the objective lens stage; connected to the objective stage, the at least one flexible objective lens support being configured to be relatively rigid in the axial direction of the objective lens positioning device and relatively flexible in other directions; an objective lens base, the objective lens base being connected to the at least one flexible objective lens support, the objective lens base being configured to be actuated to move in the axial direction and thereby move the objective lens stage and the objective lens to direct the radiation toward a target on a substrate; and an objective lens guide being configured to couple the objective lens base to a frame of the measurement device, the objective lens guide being configured to move when The objective lens base is bent when actuated, but remains connected to the frame; and a prism positioning system, the prism positioning system comprising: a prism stage, the prism stage is configured to support the prism component; and a first prism positioning device and a second prism positioning device, the first prism positioning device and the second prism positioning device are connected to the prism stage and are configured to move the prism stage in the X direction and the Y direction, respectively, the prism positioning device comprising: at least one flexible prism support, the at least one flexible prism support is connected to the prism stage, the at least one flexible A prism support is configured to be relatively rigid in an axial direction of the prism positioning device and relatively flexible in other directions; a prism base, which is connected to the at least one flexible prism support, and is configured to be actuated to move in the axial direction and thereby move the prism stage and the prism component to direct radiation toward a target on the substrate; and a prism guide, which is configured to connect the prism base to a frame of the measurement device, and the prism guide is configured to bend when the prism base is actuated but remain connected to the frame.

[0190] 52. A measuring device according to any one of the preceding aspects, wherein the first objective lens positioning device, the second objective lens positioning device and the third objective lens positioning device are configured to move the objective lens stage in the X direction, the Y direction and the Z direction, and wherein the first prism positioning device and the second prism positioning device are configured to move the prism stage independently along the X and Y directions at different times and / or simultaneously to accurately position the objective lens and / or the prism component for measurement.

[0191] 53. A metrology apparatus according to any one of the preceding aspects, wherein the first (X direction) prism positioning device comprises a single flexible support and the second (Y direction) prism positioning device comprises two flexible supports.

[0192] 54. A measuring device according to any one of the preceding aspects, wherein the two flexible support members of the second prism positioning device are located at opposite corners of the first side edge of the prism stage or near opposite corners of the first side edge of the prism stage, and the single flexible support member of the first prism positioning device is located at the center of the second side edge of the prism stage or near the center of the second side edge of the prism stage.

[0193] 55. The measurement device according to any one of the preceding aspects, wherein the two flexible supports of the second prism positioning device comprise parallel rectangular plates, and the single flexible support of the first prism positioning device comprises an elongated body with a square or rectangular cross-section.

[0194] 56. A method performed using a measurement device having a prism component and an objective lens, the method comprising: supporting the objective lens with an objective lens stage; connecting a first objective lens positioning device, a second objective lens positioning device, and a third objective lens positioning device to the objective lens stage, and moving the objective lens stage in the X direction, the Y direction, and the Z direction, respectively, the objective lens positioning device comprising: at least one flexible objective lens support, the at least one flexible objective lens support being connected to the stage, the at least one flexible objective lens support being configured to be relatively rigid in the axial direction of the objective lens positioning device and relatively flexible in other directions; an objective lens base, the objective lens base being connected to the at least one flexible objective lens support, the objective lens base being configured to be actuated to move in the axial direction, and thereby moving the objective lens stage and the objective lens to guide the radiation toward a target on a substrate; and an objective lens guide, the objective lens guide being configured to connect the objective lens base to a frame of the measurement device, the objective lens guide being configured to move when the objective lens base is moved. The objective lens base bends when actuated but remains connected to the frame; the prism component is supported by a prism stage; and a first prism positioning device and a second prism positioning device are connected to the prism stage and move the prism stage in the X direction and the Y direction respectively, the prism positioning device comprising: at least one flexible prism support, the at least one flexible prism support is connected to the prism stage, the at least one flexible prism support is configured to be relatively rigid in the axial direction of the prism positioning device and relatively flexible in other directions; a prism base, the prism base is connected to the at least one flexible prism support, the prism base is configured to be actuated to move in the axial direction, and thereby move the prism stage and the prism component to guide radiation to a target on the substrate; and a prism guide, the prism guide is configured to connect the prism base to the frame of the measurement device, the prism guide is configured to bend when the prism base is actuated but remain connected to the frame.

[0195] 57. A method according to any one of the preceding aspects, wherein the first objective lens positioning device, the second objective lens positioning device and the third objective lens positioning device are configured to move the objective lens stage in the X direction, the Y direction and the Z direction, and wherein the first prism positioning device and the second prism positioning device are configured to independently move the prism stage in the X direction and the Y direction at different times and / or simultaneously to accurately position the objective lens and / or prism components for measurement.

[0196] 58. A method according to any of the preceding aspects, wherein the first (X direction) prism positioning device includes a single flexible support and the second (Y direction) prism positioning device includes two flexible supports.

[0197] 59. A method according to any one of the preceding aspects, wherein the two flexible support members of the second prism positioning device are located at opposite corners of the first side edge of the prism stage or near opposite corners of the first side edge of the prism stage, and the single flexible support member of the first prism positioning device is located at the center of the second side edge of the prism stage or near the center of the second side edge of the prism stage.

[0198] 60. The method according to any of the preceding aspects, wherein the two flexible supports of the second prism positioning device comprise parallel rectangular plates and the single flexible support of the first prism positioning device comprises an elongated body having a square or rectangular cross-section.

[0199] The concepts disclosed herein can be associated with any superordinate imaging system for imaging sub-wavelength features, and can be used specifically with emerging imaging technologies that can produce shorter and shorter wavelengths. Emerging technologies that have been used include EUV (extreme ultraviolet), DUV lithography, which can produce wavelengths of 193nm using ArF lasers, and even 157nm using fluorine lasers. In addition, EUV lithography can produce wavelengths in the range of 20nm to 5nm by using a synchrotron or by hitting materials (solid or plasma) with high-energy electrons to produce photons in the range.

[0200] Although the concepts disclosed herein can be used for imaging on substrates such as silicon wafers, it should be understood that the disclosed concepts can be used with any type of lithography imaging system, for example, for imaging on substrates other than silicon wafers. In addition, the combinations and sub-combinations of the disclosed elements may include separate embodiments. For example, one or more of the above-mentioned elements and / or operations and / or operations may be included in separate embodiments, or one or more of the above-mentioned elements and / or operations and / or operations may be included together in the same embodiment.

[0201] The above description is intended to be illustrative rather than limiting. Therefore, it will be readily apparent to one skilled in the art that modifications may be made as described without departing from the scope of the claims described below.

Claims

1. A positioning system for an optical element of a measuring device, the positioning system comprising: Stage; as well as A positioning device, the positioning device comprising: at least one flexible support coupled to the stage, the at least one flexible support configured to be relatively rigid in an axial direction of the positioning device and relatively flexible in other directions; a base coupled to the at least one flexible support, the base being configured to be actuated to move in the axial direction and thereby move the stage; and A guide is configured to couple the base to a frame of the metrology device, the guide being configured to flex when the base is actuated.

2. The system according to claim 1, wherein: The positioning system includes a first positioning device, a second positioning device, and a third positioning device, which are coupled to the stage and are configured to move the stage in an X direction, a Y direction, and a Z direction, respectively.

3. The system according to claim 2, wherein: The first positioning device, the second positioning device and the third positioning device are configured to independently move the stage in the X direction, the Y direction and the Z direction at different times and / or simultaneously to accurately position the optical element for measurement, the optical element being supported by the stage.

4. The system according to claim 2 or 3, wherein: The first positioning device comprises a single flexible support, the second positioning device comprises two flexible supports, and the third positioning device comprises at least three flexible supports.

5. The system according to any one of claims 2 to 4, wherein: The third positioning device includes four flexible supports, and the four flexible supports are positioned at or near four corresponding corners of the stage.

6. The system according to claim 4 and 5, wherein: The single flexible support of the first positioning device is located at or near the center of a first side edge of the stage.

7. The system according to claim 6, wherein: The two flexible supports of the second positioning device are located at or near opposite corners of a second side edge of the stage, and the two flexible supports are configured to reduce or prevent undesired rotation of the stage.

8. The system according to claim 7, wherein: The four flexible supports of the third positioning device are coupled to the top surface of the stage and are configured to reduce or prevent undesired rotation and / or tilting of the stage.

9. The system according to claim 8, wherein: The four flexible supports of the third positioning device are positioned around the Porro prism of the measurement device.

10. The system according to any one of claims 1 to 9, wherein: The optical element is an objective lens.

11. The system according to any one of claims 1 to 10, wherein: The guide includes two parallel flexible plates positioned on opposite sides of the base.

12. The system according to any one of claims 1 to 11, wherein: The frame is a sensor frame of the measurement device.

13. The system according to any one of claims 1 to 12, wherein: The positioning device is configured to move the optical element for overlay measurement.

14. The system according to claim 13, wherein: The overlay measurement is for a semiconductor wafer and is performed as a part of a semiconductor manufacturing process.

15. The system of any one of claims 1 to 14, the positioning device further comprising an actuator coupled to the base, the actuator being configured to move the base in the axial direction and thereby move the stage and the optical element supported by the stage.

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