KR20240011734A - Measurement system for extreme ultraviolet light sources - Google Patents

Abstract

The metrology system includes an optical device, a detection device, and a control device in communication with the detection device. The optical device is configured to generate an optical probe that propagates in the probe area along a probe optical axis that intersects the target axial path, the target axial path extending primarily along the X axis of the X, Y, Z coordinate system. The detection device is configured to detect light generated at a plurality of distinct wavelengths, each wavelength being associated with a distinct position along the It is generated from interactions in the probe area between targets moving along a directional path. The control device is configured to analyze the detected light and determine position information related to the target along the X-transverse axis of the X, Y, Z coordinate system.

Description

Measurement system for extreme ultraviolet light sources

Cross-reference to related applications

This application claims priority from U.S. Application No. 63/191,584, entitled “METROLOGY SYSTEM FOR EXTREME ULTRAVIOLET LIGHT SOURCE,” filed May 21, 2021, which application is hereby incorporated by reference in its entirety .

The disclosed object relates to a measurement system for determining positional information of a target moving along a target axial path.

Extreme ultraviolet (EUV) light, e.g., electromagnetic radiation (sometimes also referred to as soft For example, very small features are manufactured on silicon wafers.

Methods for generating EUV light include, but are not necessarily limited to, converting a material with an element, such as xenon, lithium, or tin, into a plasma state with an emission line in the EUV range. In one such method, commonly called laser-generated plasma (“LPP”), the required plasma is an amplified light beam, which can be referred to as a driving laser, targeting a target in the form of, for example, a droplet, plate, tape, stream or cluster of material. It can be created by irradiating materials. For this process, plasma is typically generated in a sealed vessel, such as a vacuum chamber, and is monitored using various types of metrology equipment.

A lithographic apparatus is a machine that applies a desired pattern onto a substrate, usually a target portion of the substrate. Lithographic devices can be used, for example, in the manufacture of integrated circuits (ICs). In that case, a patterning device, interchangeably referred to as a mask or reticle, can be used to create a circuit pattern to be formed on the individual layers of the IC being formed. This pattern may be transferred onto a target portion (e.g., comprising a portion of one or several dies) on a substrate (e.g., a silicon wafer). Transfer of the pattern is typically through imaging into a layer of radiation-sensitive material (e.g., resist) provided on the substrate. Typically, a single substrate will contain a network of sequentially patterned adjacent target portions. A typical lithographic apparatus exposes the entire pattern to the target part at once, a so-called stepper, in which each target part is irradiated, and the radiation beam scans the pattern in a given direction (the "scanning" direction) and parallel or anti-parallel to this direction. It includes a so-called scanner in which each target portion is irradiated by simultaneously scanning the target portions. It is also possible to transfer the pattern from the patterning device to the substrate by imprinting the pattern onto the substrate.

Extreme ultraviolet (EUV) light, e.g., electromagnetic radiation (sometimes referred to as soft The device can be used to create extremely small features on a substrate, such as a silicon wafer. Methods for generating EUV light include, but are not necessarily limited to, converting a material with an element with an emission line in the EUV range, such as xenon (Xe), lithium (Li), or tin (Sn), to a plasma state. It doesn't work. For example, in one such method, called laser-generated plasma (LPP), a plasma can be generated by irradiating a target material with an amplified light beam, which can be referred to as a driving laser, which can be driven into, for example, droplets. , are interchangeably referred to as fuels with reference to LPP sources in the form of plates, tapes, streams or material clusters. For this process, plasma is typically generated in a sealed vessel, such as a vacuum chamber, and is monitored using various types of metrology equipment.

In some overall aspects, a metrology system includes an optical device, a detection device, and a control device in communication with the detection device. The optical device is configured to generate an optical probe containing a plurality of distinct wavelengths of light. The optical probe includes distinct wavelengths of light propagating along the probe optical axis intersecting the target axial path in the probe area. The detection device is configured to detect light generated at a plurality of distinct wavelengths. The generated light results from interaction in the probe area between the optical probe and the target moving along the target axial path. The control device is configured to analyze the detected light and determine, based on the analysis, one or more characteristics associated with one or more of the target and the target axial path.

An implementation form may include one or more of the following features. For example, the control device may also be in communication with the optical device.

The optical device may include, as an optical probe, one or more optical sources configured to generate a plurality of probing light beams, each probing light beam propagating along a probe optical axis intersecting the target axial path, each probing light beam having a distinct It has a central wavelength. Each probing light beam may have a distinct central wavelength focused at a distinct location along the probe optical axis and within the probe area. The optical device may include, as an optical probe, one or more optical sources configured to generate a probing light beam, the probing light beam propagating along a probe optical axis intersecting the target axial path, the probing light beam being a continuous beam of central wavelength. Defined by the spectrum.

An optical probe can have distinct focal points along the probe optical axis and within the probe area. The metrology system may also include cylindrical focusing optics in the path of the optical probe, the cylindrical focusing optics being configured to form a separate focus as an optical curtain of the optical probe along a direction perpendicular to the probe optical axis.

The optical probe may be collimated along the probe optical axis or may be imaged in the probe area.

The detection device may include a plurality of detectors, each detector configured to detect light generated from the interaction between each probing light beam of the optical probe and the target. Each detector may be configured to detect a portion of each probing light beam incident on the target. Each detector being configured to detect a portion of each probing light beam incident on the target may include each detector being configured to detect a portion of each probing light beam being reflected or scattered from the target. Each detector may be configured to detect generated light having a wavelength distinct from the wavelength of generated light detected by the remaining detectors. The detection device may be configured to distinguish the light produced between each distinct wavelength.

The generated light may travel along a path that is separate from the probe optical axis and also separate from the target axial path.

The generated light may travel along a path parallel to the actuation axis, the actuation axis being defined by the direction in which the one or more actuating light beams travel, and the one or more actuating light beams interacting with the target in a target area downstream of the probe area. do. The generated light may be or include a portion of the probe light beam reflected back from the target along the operating axis. The generated light may interact with at least a portion of the same optical system with which the one or more actuating light beams interact.

Along the target axial path, the probe area may be upstream of the target area where the target interacts with one or more actuating light beams. The target axial path may extend at least along the X axis and the probe optical axis may not be parallel to the X axis. The control device may be configured to determine the position of the target along the Y direction perpendicular to the X axis. The probe optical axis may be parallel to the Y axis and the actuating light beam may move generally along the Z axis. The plurality of wavelengths of light may have a range such that the wavelength of the light changes along the Y axis. The probe optical axis may be perpendicular to the Y axis. Light of multiple wavelengths may be extended such that the wavelength of light changes along the Y axis.

One or more actuating light beams comprising: a first amplified light beam configured to interact with the target to modify the shape and movement of the target and thereby form a modified target; and a first amplified light beam configured to interact with the modified target to polarize the modified target. and a second amplified light beam configured to convert the ultraviolet light into an emitting plasma.

The control device is configured to adjust one or more characteristics associated with one or more of the target and the target axial path, wherein the control device is configured to: instruct the target material supply to adjust one or more aspects associated with the creation of the target; and the control device is configured to instruct the actuating light source to adjust one or more aspects related to the production of one or more actuating light beams that interact with a target in a target area downstream of the probe area; It may include one or more of:

The detection device may be configured to detect light produced at a plurality of distinct wavelengths at a rate as fast as or faster than the rate at which the target passes through the probe area. The control device may be configured to effect adjustments to one or more characteristics associated with the target on which analysis of the target is based. The control device is configured to adjust one or more characteristics associated with the target, wherein the control device is configured to instruct the actuating light source to adjust the pointing of the one or more actuating light beams that interact with the target at a target area downstream of the probe area. This may include coordination of pointing with respect to the Z axis of the X, Y, Z coordinate system - where the target axial path extends mostly along the

In another overall aspect, an extreme ultraviolet (EUV) optical system is configured to form a flow of targets directed to a target area, each target moving along a target axial path extending primarily along the X axis of the X, Y, Z coordinate system. target supply; an actuating optical source configured to generate one or more actuating light beams directed to a target area, wherein the at least one actuating light beam is configured to interact with the target to form a modified target; and a measurement system. The metrology system includes an optical device, a detection device, and a control device in communication with the detection device. The optical device is configured to generate an optical probe that propagates along the probe optical axis intersecting the target axial path in the probe area. The detection device is configured to detect light generated at a plurality of distinct wavelengths, each wavelength being associated with a distinct position along the It is generated from interactions in the probe area between targets moving along a directional path. The control device is configured to analyze the detected light and determine position information related to the target along the X-transverse axis of the X, Y, Z coordinate system.

An implementation form may include one or more of the following features. For example, the one or more actuating light beams may include a first amplified light beam configured to interact with the target to modify the shape and movement of the target and thereby form a modified target, and a first amplified light beam configured to interact with the modified target to thereby modify the target. and a second amplified light beam configured to convert the target into a plasma that emits extreme ultraviolet light.

In another general aspect, a metrology system includes an optical device, a detection device, and a control device in communication with the detection device. The optical device is configured to generate an optical probe that propagates in the probe area along a probe optical axis that intersects the target axial path, the target axial path extending primarily along the X axis of the X, Y, Z coordinate system. The detection device is configured to detect light generated at a plurality of distinct wavelengths, each wavelength being associated with a distinct position along the It is generated from interactions in the probe area between targets moving along a directional path. The control device is configured to analyze the detected light and determine position information related to the target along the X-transverse axis of the X, Y, Z coordinate system.

An implementation form may include one or more of the following features: For example, the optical probe may be a broadband optical probe. The control device may be configured to determine position information related to the target along the X axis of the X, Y, Z coordinate system based on analysis of the detected light.

1 includes an optical device for generating an optical probe directed to a probe area through which a target passes, a detection device for detecting generated light from the probe area, and a control device configured to determine position information of the target from the generated light. This is a block diagram of the measurement system.
Figure 2A is a block diagram of an implementation of the metrology system of Figure 1, where the probe optical axis of the optical probe is parallel to the Y axis of the X, Y, Z coordinate system.
Figure 2b is a schematic diagram showing the probe area of the metrology system of Figure 2a, where the target moves along the -X direction and is not offset from Y=0 and the optical probe contains three probing light beams.
FIG. 2C is a schematic diagram showing the detection device of the measurement system of FIGS. 2A and 2B.
Figure 2d is a front view of an implementation of the sensor device of the detection device of Figure 2c, the sensor device comprising a plurality of detectors, each detector emitting generated light of one of the distinct wavelengths λ1, λ2, λ3. configured to detect.
FIG. 2E is a set of graphs, each graph corresponding to the output from each detector of the sensor device of FIGS. 2C and 2D for a target positioned as shown in FIG. 2B.
Figure 2f is a schematic diagram showing the probe area of the metrology system of Figure 2a, where the target is offset from Y=0.
FIG. 2G is a set of graphs, each graph corresponding to the output from each detector of the sensor device of FIGS. 2C and 2D for a target positioned as shown in FIG. 2F.
Figure 3A is a block diagram of an implementation of the metrology system of Figure 1, where the probe optical axis of the optical probe is parallel to the Z axis of the X, Y, Z coordinate system such that the probe optical axis intersects the target axial path.
Figure 3b is a schematic diagram showing the probe area of the metrology system of Figure 3a, where the target moves along the -X direction and is not offset from Y=0, the optical probe has a lateral extent along the Y axis, and also There is color variation along the range.
FIG. 3C is an illustrative schematic diagram showing a view of the probe area of the metrology system of FIGS. 3A and 3B, including a block diagram of an implementation of the detection device.
4A to 4C are schematic diagrams of the probe area of the metrology system of FIGS. 3A to 3C, where the target interacts with the optical probe at different positions along the Y axis and the detection device detects these differences in positions along the Y axis. It is configured to capture.
Figure 5 is a schematic diagram of an implementation of the metrology device of Figure 3A, wherein optical probes (collectively, probing light beams) move in the probe area along a path parallel to an actuation axis, such actuation axis being such that one or more actuation light beams It is defined by the direction of movement in the target area.
FIG. 6 is a block diagram of an extreme ultraviolet (EUV) light source including an implementation of the metrology system of FIG. 1 , wherein the EUV light source, when operating, supplies an EUV light beam to an output device, which may be a lithography exposure device.
FIG. 7 is a flow diagram of the procedure performed by the metrology system of FIG. 1 , FIG. 2A or FIG. 3A to determine positional information related to a target along the X-axis and the X-transverse axis.

Referring to FIG. 1 , the metrology system 100 is configured to determine position information of a target 105 moving along a target axial path 110 toward the target area 115 . At target area 115 , target 105 interacts with one or more actuating light beams 120 . Target axial path 110 extends generally along the -X direction of the (shown in ), one or more actuating light beams 120 extend generally along the Z axis of this X, Y, Z coordinate system. Accordingly, the target 105 generally moves along the -X direction while heading toward the target area 115. However, due to various perturbations within the chamber or due to the flow physics of target 105, target 105 may also include movement along one or more directions perpendicular to the X axis and such movement is in the YZ plane. The metrology system 100 is configured to determine positional information of the target 105 along the X axis and also along a direction perpendicular to or across the X axis (X-transverse axis). And in some implementations, metrology system 100 is particularly useful for determining positional information of a target 105 along a Y axis, which Y axis is generally perpendicular to the Z axis, and wherein one or more actuating light beams are positioned along the Z axis. move (Figures 2a and 3a).

The measurement system 100 includes an optical device 125, a detection device 135, and a control device 150. The optical device 125 is configured to generate an optical probe 130 that propagates along the probe optical axis 130OA intersecting the target axial path 110 in the probe area 131 . The detection device 135 is configured to detect the generated light 136. The generated light 136 is generated from the interaction in the probe area 131 between the optical probe 130 and the target 105 (within the probe area 131 ) moving along the target axial path 110 . For example, the generated light 136 may be a portion of the optical probe 130 reflected off the target 105, with the signal reaching a maximum as the target 105 is completely contained within the thickness of the optical probe 103. This signal increases as the target 105 first reaches the optical probe 130, and then decreases as the target 105 exits the optical probe 130.

The generated light 136 may have a specific wavelength selected from a plurality of distinct wavelengths at any one instant. Detection device 135 is configured to detect light of any of these distinct wavelengths. Moreover, each wavelength is associated with a distinct position along the X-transverse axis of the X, Y, Z coordinate system, with the X-transverse axis being the Y or Z axis of the In some specific examples that follow, the X-transverse axis is the Y axis.

The control device 150 is in communication with the detection device 135. Control device 150 may also be in communication with optical device 125. The control device 150 is configured to analyze the detected generated light 136 and determine positional information about the target 105 along both the X axis and the X-transverse axis of the X, Y, Z coordinate system. Accordingly, in addition to determining the time at which the target 105 interacts with the optical probe 130, the control device 150 determines the wavelength of the generated light 136 along the same direction in which it changes, i.e. the Positional information regarding the target 105 along an axis may be determined. The control device 150 also controls the target 105 and the target 105 based on the determined positional information of the target 105 along the Adjustment 160 may be effected on one or more characteristics associated with one or more of the axial paths 110 . For example, adjustments 160 may be made to one or more actuating light beams 120 to change one or more aspects of actuating light beams 120 relative to target 105 . As another example, the pointing and/or timing of the pulses of the actuating light beam 120 may be adjusted. As another example, adjustment 160 may be for a target supply device ( FIGS. 2 and 3 ) that creates a target 105 and thereby adjusts aspects related to how the target 105 is created. In this way, the control device 150 controls the trajectory of the target 105 and the timing at which the target reaches the target area 115, so that the pulses of the actuating light beam 105 are directed from the target area 115 to the target 105. ) to investigate.

Target 105 is a target mixture containing target material and optional impurities such as non-target particles. Target 105 may be, for example, a droplet of liquid or molten metal, a portion of a liquid stream, a solid particle or cluster, a solid particle contained within a liquid droplet, a foam of target material, or a portion of a liquid stream. It may be a solid particle. Target 105 may include, for example, water, tin, lithium, xenon, or any material that has an emission line in the EUV range when converted to a plasma state. For example, target 105 may include elemental tin, such as pure tin (Sn); As tin compounds such as SnBr ₄ , SnBr ₂ , and SnH ₄ ; It can be used as a tin alloy, such as a tin-gallium alloy, a tin-indium alloy, a tin-indium-gallium alloy, or any combination of these alloys. Target 105 is formed as a stream of targets 105 that pass through probe area 131 and are directed to target area 115 . The rate at which the target 105 is generated, and also the rate at which the target 105 passes through the probe area 131, is on the order of several or tens of kilohertz (e.g., at least 50 kHz and at most 100 kHz or more). kHz). Details on how target 105 is created are provided below with reference to FIG. 6.

Optical device 125 may be configured to generate optical probe 130 containing multiple distinct wavelengths of light simultaneously. Moreover, each of the components of light within optical probe 130 having a distinct wavelength may interact with target 105 at a distinct location along the X-transverse axis within probe area 131 . Accordingly, the optical probe 130 has a chromatic variation along the X-transverse axis. For example, optical probe 130 may have a first wavelength generated at a first location along the X-transverse axis, a second wavelength generated at a second location along the It may include a third wavelength generated at 3 positions. As another example, the optical probe 130 is created as a light curtain or other beam shape that is a light beam crossing the target axial path 110 of the target 105. In some implementations, optical probe 130 is a continuous wave light beam. It is possible in some implementations for the optical probe 130 to become a pulsed light beam if the optical probe 130 is pulsed at a sufficiently high frequency (e.g., higher than the rate at which the target 105 is generated). In some implementations, optical probe 130 consists of one or more laser beams. In another implementation, optical probe 130 consists of one or more light beams, which may not be laser beams.

This This is because the detection device 135 is configured to detect this change in the wavelength distribution along the X-transverse axis. Different implementation forms for optical device 125 and optical probe 130 are described with reference to FIGS. 2A, 3A and 5.

Detection device 135 may include one or more optical sensors, such as photodiodes, operating at a sufficiently high bandwidth to detect (via generated light 136) each target 105 in the stream. Therefore, if target 105 is generated at a rate of 50 kHz, the optical sensor in detection device 135 is fast enough to detect and process the generated light 136 at a rate of 50 kHz (without aliasing). . The detection device 135 is configured to detect the wavelength distribution of the generated light 136. This means that the detection device 135 can distinguish between different wavelengths of light in the light 136 generated due to the X-transverse color change in the optical probe 130. Details of detection device 135 are described below with reference to FIGS. 2A, 3A and 5.

The control device 150 includes an electronic processor and an electronic storage unit. The processor may be any type of electronic processor and may also be more than one electronic processor. The processor may include one or more processors suitable for executing computer programs, such as general-purpose or special-purpose microprocessors, and any one or more processors of any type of digital computer. Typically, a processor receives instructions and data from read-only memory, random access memory, or both. The electronic storage may, when executed, cause the processor to effect adjustments to other components of metrology system 100, such as detection device 135, and one or more characteristics associated with one or more of target 105 and target axial path 110. It stores instructions, possibly as a computer program, that allow it to be in communication with its components. Electronic storage may include volatile memory such as RAM. Electronic storage may include both non-volatile portions or components and volatile portions or components. Moreover, control device 150 may include a variety of individual modules, each module may be dedicated to a particular task. Additionally, these modules may be physically separate from each other or may be integrated with other parts of metrology system 100.

2A and 2B, an implementation 200 of the metrology system 100 is shown. In metrology system 200, probe optical axis 230OA is parallel to the Y axis of the X, Y, Z coordinate system. Accordingly, the optical probe 230 moves along the Y axis of the measurement system 200. Metrology system 200 includes an optical device 225 that produces an optical probe 230 . Optical probe 230 includes three probing light beams 230_1, 230_2, 230_3 (more clearly visible in FIG. 2B), each of which has a separate central wavelength. It is at (λ1, λ2, λ3). Each probing light beam 230_1, 230_2, 230_3 propagates along probe optical axis 230OA (parallel to the Y axis) and intersects target axial path 210. Moreover, each probing light beam 230_1, 230_2, and 230_3 is focused at a separate respective location Y_1, Y_2, and Y_3 along the probe optical axis 230OA.

In some implementations, the probing light beams 230_1, 230_2, and 230_3 are laser beams. The probing light beams 230_1, 230_2, and 230_3 may be circular in intensity profile (i.e., in the XZ plane plane), so they have a typical through focus laser waist profile. In this implementation, the probing light beams 230_1, 230_2, 230_3 have a transverse shape symmetrical about the Y axis. In some implementations, the probing light beams 230_1, 230_2, 230_3 may be non-circular beams, where the longitudinal position of the beam waist may be different for different transverse directions. This shape can be created by using a cylindrical lens. For cylindrical focused beams (“curtains”) the transverse profile has a chisel-like shape and is elongated in the Z axis.

In some implementations, optical device 225 includes a light source, such as a laser, and a device for converting a single light beam into three probing light beams 230_1, 230_2, 230_3 of distinct wavelengths λ1, λ2, λ3. And also includes optical components with distinct wavelengths at Y_l, Y_2, and Y_3. In another implementation, optical device 225 includes three lasers, each laser producing respective probing light beams 230_1, 230_2, 230_3 of distinct wavelengths λ1, λ2, λ3. In another implementation, optical device 225 includes a single laser or broadband light source that generates three probing light beams 230_1, 230_2, 230_3 of distinct wavelengths λ1, λ2, λ3. Probing light beams 230_1, 230_2, and 230_3 may be combined from a light source or light sources toward the probe area 231 using one or more fiber optic devices. Optical device 225 may further include a focusing device within the path of each probing light beam 230_1, 230_2, 230_3, wherein the focusing device directs this particular probing light beam to its respective and It is configured to focus on separate focus positions (Y_1, Y_2, Y_3).

In some implementations, the wavelengths λ1, λ2, λ3 may be in the visible and/or near-infrared (NIR) range. The spacing between each wavelength (e.g., between λ1 and λ2 or between λ2 and λ3) depends on the type and design of the optics (such as filters) within optical device 225. And in some implementations, the wavelength spacing may be on the order of tens of nanometers (nm), about 20 nm, about 30 nm, or about 40 nm.

Although three probing light beams 230_1, 230_2, and 230_3 are shown in one implementation of metrology system 200, in other implementations optical probe 230 includes more than three probing light beams.

Referring also to FIG. 2C , the detection device 235 is configured to receive the generated light 236. Moreover, the detector 235 is oriented so that it can detect the generated light 236 (which may be light reflected by the target 205) regardless of the position of the target 205 within the probe area 231. The generated light 236 may correspond to that portion of each probing light beam 230_1, 230_2, and 230_3 that is reflected from or scattered from the target 205. As can be seen, the generated light 236 may travel along a path different from the probe optical axis 230OA and also different from the target axial path 210.

The detection device 235 includes an optical component 237 for processing and modifying the generated light 236 and a sensor device 242 for receiving the processed light 239 from the optical component 237 . Optical components 237 include one or more collection optics 238, such as lenses, for beam shaping of the generated light 236, and optionally include spatial filters and/or slit apertures. Optical components 237 may also include folding optics, such as mirrors and/or prisms. The optical component 237 includes a chromatic separation device 240 which splits the generated light 236 into light portions 241_1 and 241_2, respectively, having separate respective wavelengths λ1, λ2 and λ3. , 241_3) may be a passive set of optical devices for separation. For example, chromatic separation device 240 may include a set of dichroic beam splitters or mirrors. In this way, the detection device 235 can distinguish the generated light 236 between distinct wavelengths λ1, λ2, and λ3.

Referring also to FIG. 2D, the sensor device 242 includes a plurality of detectors 242_1, 242_2, and 242_3, each detector generating light 236 of one of distinct wavelengths λ1, λ2, and λ3. and the generated light 236 is generated from the interaction between the optical probe 230 and the target 205 in the probe area 231. Each detector 242_1, 242_2, and 242_3 may be a zone or region of a light detector. For example, detector 242_1 may correspond to a first set of pixels of the photodiode array, detector 242_2 may correspond to a second set of pixels of the photodiode array, and detector 242_3 may correspond to a first set of pixels of the photodiode array. It can correspond to 3 pixel sets. In other implementations, each detector 242_1, 242_2, 242_3 may correspond to a separate and distinct photodiode or photodiode array.

The outputs 243_1, 243_2, and 243_3 of each detector 242_1, 242_2, and 242_3 are provided to the control device 250 for analysis. If the detector is a photodetector, outputs 243_1, 243_2, 243_3 correspond to the amplitude of the photocurrent generated from light interacting with the active area of that detector over time. This photocurrent is proportional to the absorbed (or incident) light intensity over a wide range of light output. Additionally, the use of photodetectors allows detection of targets 205 at a rate as fast as they are generated, such that control device 250 can analyze each target 205 that interacts with optical probe 230. makes it possible to carry out

As shown in Figure 2E, the respective outputs 243_1, 243_2, 243_3 of detectors 242_1, 242_2, 242_3 are shown for interaction in Figure 2B. Specifically, and for example in Figure 2B, target 205 is mostly aligned with focus Y_2 of probing light beam 230_2. Accordingly, the output 243_2 of the detector 242_2 has a larger amplitude than the output 243_1 of the detector 242_1 and the output 243_3 of the detector 242_3.

As another example, in Figure 2F, target 205 has deviated along the -Y direction and is now more closely aligned with the focus Y_1 of probing light beam 230_1. The respective outputs 243_1, 243_2, and 243_3 of the detectors 242_1, 242_2, and 242_3 for the location of the target 205 in FIG. 2F are shown in FIG. 2G. As can be seen, the amplitude of output 243_1 from detector 242_1 is largest. Additionally, because the target 205 is offset from Y=0, the output 243_3 at detector 242_3 is less than the output 243_2 at detector 242_2.

Control device 250 can determine the position of target 205 along the Y direction by analyzing the ratio of these output signals to each other. For example, control device 250 may determine a ratio R12 of output 243_1 to output 243_2; ratio of output 243_3 to output 243_2 (R32); Alternatively, the ratio (R13) of the output (243_1) to the output (243_3) can be analyzed.

In the implementation of FIG. 2A , one or more actuating light beams 220 are generated by an actuating light source 221 . One or more actuating light beams 220 extend generally along a direction parallel to the Z axis such that the actuating light beam 220 interacts with the target 205 in the target area 215 downstream of the probe area 231. . In this implementation, optical probe 230 and probing light beams 230_1, 230_2, 230_3 propagate along a direction that is not parallel to the direction of actuating light beam 220. For example, optical probe 230 (and probing light beams 230_1, 230_2, 230_3) may be perpendicular to the direction of actuating light beam 220. Additionally, target 205 is created by target supply device 206. One or more of the target supply 206 and the actuating light source 221 may receive commands for adjustments 260 from the control device 250 based on the control device 250's analysis of the output from the detection device 235. Receive. Specifically, the control device 250 determines position information (e.g., position) of the target 205 along the Y axis of the X, Y, Z coordinate system. The control device 250 then determines whether and how to adjust the target supply 206 and/or the actuating light source 221 to account for drift of the target 205 along the Y axis so that the target 205 has one It is possible to ensure that the above actuating light beam 220 enters the target area 215 at the appropriate moment and location to interact with it, thereby efficiently generating EUV light.

Referring to FIG. 3A, another implementation of the metrology system 100 is shown. In metrology system 300, probe optical axis 330OA is parallel to the Z axis of the X, Y, Z coordinate system such that probe optical axis 330OA intersects target axial path 310. Accordingly, in metrology system 300, optical probe 330 moves along the Z axis at least in probe area 331.

Metrology system 300 includes an optical device 325 that produces an optical probe 330 . The optical probe 330 is a beam with a transverse color change. That is, the color change extends along a direction perpendicular to the direction in which the optical probe 330 moves. In this example, the color change extends along the Y axis. Since the wavelength distribution of the generated light 336 changes as the target 305 moves along the Y axis, the lateral color change of the optical probe 330 enables measurement of the change in position of the target 305 along the Y axis. do.

For this purpose, the metrology system 300 includes a detection device 335 configured to receive the generated light 336, and a detection device 335 configured to receive the output from the detection device 335 and analyze the output and target along the X and Y directions ( and a control device 350 configured to determine location information regarding 305). The control device 350 may also control the target 305 and the target axis based on the determined positional information of the target 305 along the Adjustment 360 of one or more characteristics associated with one or more of the directional paths 310 may be effected. Adjustment 360 is one of an actuating light source 321 (thereby altering one or more aspects of the actuating light beam 320 relative to the target 305) and a target supply device 306 that generates the target 305. Or it can be done for both, thereby adjusting aspects related to how the target 305 is created. In this way, the control device 350 controls the trajectory of the target 305 and the timing at which the target reaches the target area 315, such that the pulses of the actuating light beam 305 are directed from the target area 315 to the target 305. ) and effectively generate EUV light.

3B and 3C, the optical probe 330 has a lateral extent along the Y axis, and furthermore there is a color change along this lateral extent. In this particular implementation, for simplicity, five distinct wavelengths (λ1, λ2, λ3, λ4, λ5) are positioned across each portion of the optical probe 330 (330_1, 330_2, 330_3, 330_4, 330_5). It is expressed as a color change in (330). However, there may be fewer or more distinct waves than five. And (as shown in Figure 3c) it is possible for the chromatic changes to be at distinct central wavelengths; Or alternatively, it is possible for the chromatic change to be a continuous change in wavelength over a transverse range.

The detection device 335 includes a chromatic separation device 340, which is a passive set of optical devices that separates the generated light 336 into light portions 341_1, 341_2, 341_3, 341_4, and 341_5. Each part has a separate wavelength (λ1, λ2, λ3, λ4, λ5). Color separation device 340 converts wavelength spacing to spatial spacing. For example, chromatic separation device 340 may include a set of dichroic beam splitters or mirrors. As another example, chromatic separation device 340 includes a dispersive element, such as a grating, or a dispersive optical element, such as a prism, that can be transmissive or reflective. In this way, the detection device 335 can distinguish the generated light 336 between distinct wavelengths λ1, λ2, λ3, λ4, and λ5.

The detection device 335 also includes a sensor device 342 that receives the processed light portions 341_1, 341_2, 341_3, 341_4, 341_5. The sensor device 342 includes a plurality of detectors 342_1, 342_2, 342_3, 342_4, and 342_5, each detector generating light 336 at one of distinct wavelengths λ1, λ2, λ3, λ4, and λ5. This generated light is generated from the interaction between the optical probe 330 and the target 305 in the probe area 331. Sensor device 342 may further include a chromatic beam separation system, such as a dispersive element (e.g., a grating or prism), or a series of dichroic filters or beam splitters, or a monolithic filter configuration.

Each detector 342_1, 342_2, 342_3, 342_4, and 342_5 may be a region or region of photodetectors. For example, detector 342_1 may correspond to a first set of pixels of the photodiode array, detector 342_2 may correspond to a second set of pixels of the photodiode array, and detector 342_3 may correspond to a first set of pixels of the photodiode array. It can correspond to 3 pixel sets. Detector 342_4 may correspond to a fourth set of pixels of the photodiode array, and detector 342_5 may correspond to a fifth set of pixels of the photodiode array. In another implementation, each detector 342_1, 342_2, 342_3, 342_4, 342_5 may correspond to a separate and distinct photodiode or photodiode array.

In the example shown in Figure 3C, target 305 is interacting with portion 330_3 of optical probe 330. In this example, target 305 is fairly well aligned with the X axis and does not deviate too far along the Y axis. Therefore, the generated light 336 will have a dominant wavelength λ3 and the signal associated with wavelength λ3 will dominate the overall signal analyzed by detection device 335. Accordingly, the optical portion 341_3 has much greater amplitude and power than the other optical portions and the signal at detector 342_3 is much larger than the signal at the other detectors.

Figures 4A-4C show the generated light 336 for various positions of the target 305 along the Y axis. For example, in Figure 4A, target 305 interacts with portion 330_4 and the dominant wavelength λ4 is reflected in the -Y direction as the generated light 336 to detection device 335. is offset along . Accordingly, detector 342_4 detects the largest amplitude of light, while the other detectors detect relatively small amplitudes of light. In Figure 4b, target 305 is offset along the +Y direction such that target 305 interacts with portion 330_2 and the dominant wavelength λ2 is reflected as generated light 336 to detection device 335. . Accordingly, detector 342_2 detects the largest amplitude of light, while the other detectors detect relatively small amplitudes of light. 4C, target 305 is offset significantly along the -Y direction such that target 305 interacts with portion 330_5 and the dominant wavelength λ5 is reflected as generated light 336 to detection device 335. do. Accordingly, detector 342_5 detects the largest amplitude of light, while the other detectors detect relatively small amplitudes of light.

In some implementations, optical probe 305 may be a broadband optical probe beam, a beam with a continuous optical spectrum across the Y axis. In this example, optical device 325 may include a single broadband light source that produces optical probe 305 . In another implementation, optical probe 305 may be comprised of a plurality of probing light beams, each probing light beam having a distinct center wavelength. In this example, optical device 325 may include a plurality of physically distinct light sources, each producing a probing light beam of a distinct central wavelength. In another implementation, optical device 325 may be a supercontinuum light source for converting laser light into light with a very wide spectral bandwidth to generate a supercontinuous optical spectrum. Optical device 325 may use prisms and/or gratings to achieve color separation. Additionally, the design of the optical device 325 is used to generate the optical probe 305, including evaluation of the physical distance and signal level (that the optical probe 305 must travel to reach the probe area 331). Parameters such as magnification and numerical aperture of the components can be determined.

The detection device 335 may be implemented in any suitable manner, for example as a linear sensor array with a grating, to convert the wavelength of the generated light 336 into a spatial interval. Detection device 335 may include a camera pixel array with an integrated color filter, or may include a plurality of photodiodes with a dichroic coating.

An implementation 500 of the metrology system 300 is shown in FIG. 5 . Similar to metrology system 300, in metrology system 500, probe optical axis 530OA is aligned with the Z axis of the X, Y, Z coordinate system such that probe optical axis 530OA intersects target axial path 510. parallel Accordingly, in metrology system 500, optical probe 530 moves along the Z axis at least in probe area 531.

Metrology system 500 includes an optical device 525 that produces an optical probe 530 . Optical probe 530 is a beam with a transverse chromatic variation that is projected onto a target axial path 510 . That is, the color change extends along a direction perpendicular to the direction in which the optical probe 530 moves. In this example, the chromatic change extends along the Y axis (as shown in Figures 3b and 3c). Since the wavelength distribution of the generated light 536 changes as the target 505 moves along the Y axis, the lateral color change of the optical probe 530 allows measurement of the change in the position of the target 505 along the Y axis. Let it be done.

To this end, the metrology system 500 includes a detection device 535 configured to receive the generated light 536, and to receive the output from the detection device 535 and analyze the output and target the target along the X and Y directions. and a control device 550 configured to determine location information regarding 505 . The control device 550 also controls the target 505 and the target 505 based on the determined positional information of the target 505 along the Adjustment 560 of one or more characteristics associated with one or more of the axial paths 510 may be effected. Adjustment 560 may be performed by one of the actuating light source 521 (thereby altering one or more aspects of the actuating light beam 520 relative to the target 505) and the target supply device 506 producing the target 505. Or it can be done for both, thereby adjusting aspects related to how the target 505 is created. In this way, the control device 550 controls the trajectory of the target 505 and the timing at which the target reaches the target area 515, such that the pulses of the actuating light beam 505 are directed from the target area 515 to the target 305. ) and effectively generate EUV light.

In this implementation, optical device 525 includes a broadband light source 526, a color shaping optical element 527, and an imaging optical element 528 that generate a broadband light beam 526b having all wavelengths of interest. Chromatic shaping optical element 527 splits broadband light beam 526b into probing light beams 530_1, 530_2, 530_3, 530_4, and 530_5, each light beam having a distinct center wavelength λ1, λ2, λ3, λ4. , λ5) of the light beam. In some implementations, imaging optical element 528 includes cylindrical focusing optics (such as a cylindrical lens) within the path of probing light beams 530_1, 530_2, 530_3, 530_4, 530_5, wherein the cylindrical focusing optics are within probe area 531 ) is configured to form a distinct focus as an optical curtain along the Y axis. In another implementation, the imaging optical element 528 includes collimating optics in the path of the probing light beams 530_1, 530_2, 530_3, 530_4, and 530_5, wherein the collimating optics are configured to collimate the probing light beams 530_1 and 530_5 in the probe area 531. It is configured to collimate 530_2, 530_3, 530_4, 530_5). In another implementation, imaging optical element 528 images probing light beams 530_1, 530_2, 530_3, 530_4, 530_5 into probe area 531. That is, imaging optical elements 528 cause an image of each probing light beam to be delivered to the probe area.

In this implementation, optical probes 530 (collectively probing light beams 530_1, 530_2, 530_3, 530_4, 530_5) move in probe area 531 along a path parallel to an actuation axis, which actuation axis has one The direction in which the above operating light beam 520 moves in the target area 515 is defined. Moreover, the optical probe 530 may interact with at least some of the optical elements 523 with which the actuating light beam 520 interacts (the optical elements 523 may be referred to as actuating optical elements). For example, this may be enabled if the operating optical element has an operating range that includes the central wavelengths (λ1, λ2, λ3, λ4, λ5) of the optical probe 530. Optical probe 530 also passes through EUV light collector (e.g., mirror) 524 along a parallel path with actuating light beam 520.

The generated light 536 may be a portion of the optical probe 530 reflected from the target 505 . Moreover, the generated light 536 may be reflected back along the operating axis in the probe area 531 . In this way, the generated light 536 also interacts with at least some of the operative optical elements. Optical probe 530 is coupled into the working optical path via beam splitter 522 and the generated light 536 is coupled out of the working optical path via beam splitter 522. Beam splitter 522 may be a chromatic splitter, so that the resulting light 536 is transmitted, for example, and reflected by optical probe 530.

While the optical probe 530 and the generated light 536 interact with at least some of the actuated optical elements 523 of the metrology system 500, the optical probe 530 and/or the generated light 536 are actuated. It is possible to follow a completely separate path from optical element 523.

As discussed above, detection device 535 includes a color separation device 540 that separates generated light 536 into light portions 541_1, 541_2, 541_3, 541_4, and 541_5. It may be a passive set of optical devices 540_1, 540_2, 540_3, 540_4, and 540_5, each part having a separate respective wavelength (λ1, λ2, λ3, λ4, λ5). In this implementation, optical devices 540_1, 540_2, 540_3, 540_4, 540_5 are dichroic beam splitters or mirrors. In this way, the detection device 535 can distinguish the generated light 536 between distinct wavelengths λ1, λ2, λ3, λ4, and λ5.

Detection device 535 also includes a sensor device 542 that receives processed light portions 541_1, 541_2, 541_3, 541_4, 541_5. In practice, the relative sizes of light portions 541_1, 541_2, 541_3, 541_4, 541_5 will indicate the position of target 505 along the Y axis, while the totality of all light portions 541_1, 541_2, 541_3, 541_4, 541_5 The signal or amplitude will indicate the position of target 505 along the X axis. The sensor device 542 includes a plurality of detectors 542_1, 542_2, 542_3, 542_4, and 542_5, each detector generating one light 536 of distinct wavelengths λ1, λ2, λ3, λ4, and λ5. configured to detect a portion of, wherein the generated light 536 is generated from the interaction between the optical probe 530 and the target 505 in the probe area 531. Each detector 542_1, 542_2, 542_3, 542_4, and 542_5 may be a region or region of photodetectors. For example, detector 542_1 may correspond to a first set of pixels of the photodiode array, detector 542_2 may correspond to a second set of pixels of the photodiode array, and detector 542_3 may correspond to a first set of pixels of the photodiode array. 3 sets of pixels, with detector 542_4 corresponding to the fourth set of pixels of the photodiode array, and detector 542_5 corresponding to the fifth set of pixels of the photodiode array. In another implementation, each detector 542_1, 542_2, 542_3, 542_4, 542_5 may correspond to a separate and distinct photodiode or photodiode array.

In another implementation, the generated light 536 may be separated from the optical probe 530 using a polarization manager instead of the beam splitter 522. For example, such a polarization manager can include a polarization beam splitter system with a polarizer in front and a quarter wavelength behind to generate and split rotationally polarized beams of different handedness.

Referring to Figure 6, an implementation 600 of metrology system 100 is integrated in operation with an EUV light source 670 that supplies an EUV light beam 671 to an output device 672, which can be a lithographic exposure device. The EUV light source 670 has a first target space where each target 605 interacts with the first actuating light beam 620A to form a modified target 605m and each modified target 605m generates a second actuating light beam. and a vacuum chamber 673 defining a second target space that interacts with beam 620B. The first and second target spaces are in target area 615.

The optical device 625 and the detection device 635 are arranged to interact with the target 605 in the probe area 631 before the target enters the target area 615 .

EUV light source 670 includes an EUV light collector (such as a mirror) arranged relative to the second target space. EUV light collector 624 collects EUV light 674 emitted from plasma 675 generated when modified target 605m interacts with second actuating light beam 620B. EUV light collector 624 redirects the collected EUV light 674 as EUV light beam 671 toward output device 672. EUV collector 624 may be a reflective optical device, such as a curved mirror, that can reflect light having an EUV wavelength (i.e., EUV light 674) to form the generated EUV light beam 671.

EUV light source 670 includes a target supply device 606 that forms a stream of targets 605 directed toward a first target space for interaction with first actuating light beam 620A. Target 605 is formed of a target material that produces EUV light 674 when in a plasma state such as after interaction with second actuating light beam 620B. The first target space is, for example, a location where the target 605 is converted to a plasma state. Target supply device 606 includes a reservoir 607 defining a hollow interior configured to contain fluid target material. The target supply device 606 includes a nozzle structure 608 having an opening (or orifice) 609 at one end in fluid communication with the interior of the reservoir 607. The target material in a fluid state under the force of pressure P (as well as other possible forces such as gravity) flows from the interior of the reservoir 607 and through the opening 609 to form a flow of the target 605. The trajectory of target 605 as it emerges from aperture 609 (target axial path 610) extends generally along the -X direction; however, as discussed above, the trajectory of target 605 is in the -X direction. It is possible to include components along a vertical plane (i.e. Y and Z components).

Each modified target 605m is converted at least partially or mostly into plasma through its interaction with pulses of the second actuating light beam 620B generated by the actuating light source 621, which interaction is achieved by the second actuating light source 621. Occurs in target space. As discussed above, each target 605 is a target mixture containing target material and optionally impurities such as non-target particles. Target 605 may be, for example, a droplet of liquid or molten metal, a portion of a liquid stream, a solid particle or cluster, a solid particle contained within a liquid droplet, a foam of target material, or a portion of a liquid stream. It may be a solid particle. Target 605 may include, for example, water, tin, lithium, xenon, or any material that has an emission line in the EUV range when converted to a plasma state. For example, target 605 may include elemental tin, such as pure tin (Sn); As tin compounds such as SnBr ₄ , SnBr ₂ , and SnH ₄ ; It can be used as a tin alloy, such as a tin-gallium alloy, a tin-indium alloy, a tin-indium-gallium alloy, or any combination of these alloys.

EUV light source 670 may include a dedicated controller 678 in communication with control device 650 as well as other components of EUV light source 670 (such as target supply 606). Alternatively, it is possible for control device 650 to be part of controller 678.

The X, Y, and Z coordinate systems of the EUV light source 670 may be fixed or determined depending on the type of vacuum chamber 673. For example, chamber 673 may be defined by a series of walls, and three points on one or more walls of chamber 673 or within the space of chamber 673 have reference to the X, Y, Z coordinate system. can be provided. It is possible to secure one or more of the components of the optical device 625 and the detection device 635 to one or more walls of the chamber 673.

The EUV light source 670 may further include other measurement devices not shown. For example, EUV light source 670 may include a coarse target steering camera and a fine target steering camera positioned to view target 605 as the target moves toward the first target space. It is in communication with the controller 678. Controller 678 may analyze data from this steering camera to determine the position of target 815 in one or more of the Y and Z directions. As another example, EUV light source 670 may include a set of sensors arranged and configured to detect or sense EUV light 674; This information about EUV light 674 may be analyzed by controller 678 for use in other aspects or control of EUV light source 670.

Referring to FIG. 7 , metrology system 100 (which may be metrology system 200, 300, or 500) may perform procedure 780. As described above, metrology system 100 generates optical probe 130 (781). The optical probe 130 is directed as a curtain to cross the target axial path 110 along the X-transverse direction (which may be in the YZ plane). As target 105 traverses the curtain of optical probe 130 (and interacts with optical probe 130), light 136 is generated and then detected (782). In particular, the detection device 135 detects a plurality of distinct wavelengths of generated light 136, each wavelength being associated with a distinct location along the X-transverse direction in the X, Y, Z coordinate system. Control device 150 analyzes this detected light and determines positional information related to the target along the X-axis and the X-transverse axis (783). Based on the determined position information (783), the control device 150 determines (784) whether the target 105 is on a desired trajectory (or target axial path 110) to the target area 115. If the target 105 is not on the desired trajectory (784), the control device 150 adjusts the target 105 and the target axial direction based on the determined position information of the target 105 along the Affects adjustment 160 to one or more characteristics associated with one or more of the pathways 110 (785). The control device 150 may additionally perform other analyzes 786, such as calculating the time for the target 105 to reach the target area 115, and also to ensure that the pulse is simultaneously with the target 105 in question. A signal may be sent to the actuating light source (such as 221, 331) instructing the actuating light source (221, 331) to generate a pulse of the actuating light beam (220) at the time of reaching the target area (115) (787). . The control device 150 may additionally use the information obtained for diagnostic purposes to make long-term predictions regarding the components or stability of the EUV light source 670 over time.

The flow chart shown in FIG. 7 only shows operations related to a single target 105. In reality, target supply devices 206 and 306 are continuously producing targets 105 as described above. And because there is a continuous series of targets 105 , a continuous series of flashes of light 136 generated are detected at the detection device 135 and generated at the detection device 135 and the control device 150 There will similarly be a series of timing signals that are analyzed by . This causes the actuating light sources 221 and 321 to fire a series of pulses and irradiate the series of targets 105 in the target area 115 to generate EUV light 674. Additionally, the control device 150 may effect the adjustment 160 sequentially and for each target 105 in a feed-forward manner (i.e., before the target 105 reaches the target area 115). It works like this. This allows the target 105 to be adjusted before the target reaches the target area 115.

Embodiments may be further described using the following provisions:

1. The measurement system is:

an optical device configured to generate an optical probe comprising a plurality of distinct wavelengths of light, the optical probe comprising distinct wavelengths of light propagating along a probe optical axis that intersects the target axial path in the probe area;

a detection device configured to detect generated light at a plurality of distinct wavelengths, wherein the generated light results from interaction in the probe area between an optical probe and a target moving along a target axial path; and

A control device in communication with the detection device and configured to analyze the detected light and adjust one or more characteristics associated with one or more of the target and the target axial path based on the analysis.

2. The metrology system of clause 1, wherein the optical device is an optical probe, comprising one or more optical sources configured to generate a plurality of probing light beams, each probing light beam propagating along a probe optical axis intersecting the target axial path, Each probing light beam has a distinct central wavelength.

3. In the metrology system of clause 2, each probing light beam with a distinct central wavelength is focused at a distinct location along the probe optical axis and within the probe area.

4. The metrology system of clause 1, wherein the optical device is an optical probe, comprising at least one optical source configured to generate a probing light beam, the probing light beam propagating along a probe optical axis intersecting the target axial path, and the probing light The beam is defined by a continuous spectrum of central wavelengths.

5. In the metrology system of clause 1, the optical probe has a separate focus along the probe optical axis and within the probe area.

6. The metrology system of clause 5 further includes cylindrical focusing optics in the path of the optical probe, the cylindrical focusing optics being configured to form a separate focus as an optical curtain of the optical probe along a direction perpendicular to the probe optical axis.

7. In the metrology system of clause 1, the optical probe is collimated along the probe optical axis or imaged in the probe area.

8. The metrology system of clause 1, wherein the detection device includes a plurality of detectors, each detector configured to detect light generated from the interaction between the respective probing light beams of the optical probe and the target.

9. The metrology system of clause 8, wherein each detector is configured to detect a portion of each probing light beam incident on the target.

10. The metrology system of clause 9, wherein each detector is configured to detect a portion of each probing light beam incident on the target, and each detector is configured to detect a portion of each probing light beam that is reflected or scattered from the target. Includes.

11. The metrology system of clause 8, wherein each detector is configured to detect generated light having a wavelength distinct from the wavelength of the generated light detected by the remaining detectors.

12. In the metrology system of clause 1, the detection device is configured to distinguish the light produced between each distinct wavelength.

13. In the metrology system of clause 1, the generated light travels along a path that is separate from the probe optical axis and also separate from the target axial path.

14. In the metrology system of clause 1, the generated light moves along a path parallel to the working axis, the working axis being defined by the direction in which one or more working light beams move, and the one or more working light beams downstream of the probe area. Interact with the target in the target area.

15. In the metrology system of clause 14, the generated light is that portion of the probe light beam that is reflected back from the target along the operating axis.

16. The metrology system of clause 15, wherein the generated light interacts with at least a portion of the same optical system with which the one or more actuating light beams interact.

17. In the metrology system of clause 1, along the target axial path, the probe area is upstream of the target area where the target interacts with one or more actuating light beams.

18. In the metrology system of clause 17, the target axial path extends at least along the X axis and the probe optical axis is not parallel to the X axis.

19. In the metrology system of clause 18, the control device is configured to determine the position of the target along the Y direction perpendicular to the X axis.

20. In the metrology system of clause 19, the probe optical axis is parallel to the Y axis and the working light beam moves generally along the Z axis.

21. In the metrology system of clause 20, the plurality of wavelengths of light have a range such that the wavelengths of the light vary along the Y axis.

22. In the metrology system of clause 19, the probe optical axis is perpendicular to the Y axis.

23. In the metrology system of clause 22, the plurality of wavelengths of light are extended such that the wavelengths of the light vary along the Y axis.

24. The metrology system of clause 17, wherein one or more actuating light beams comprises: a first amplified light beam configured to interact with the target to modify the shape and movement of the target and thereby form a modified target; and a first amplified light beam configured to interact with the modified target. and a second amplifying light beam configured to operate to convert the target modified thereby into a plasma that emits extreme ultraviolet light.

25. The metrology system of clause 1, wherein the control device is configured to adjust one or more characteristics associated with the target and one or more of the target axial paths:

wherein the control device is configured to instruct the target material supply to adjust one or more aspects related to creation of the target; and

wherein the control device is configured to instruct the actuating light source to adjust one or more aspects related to the generation of one or more actuating light beams that interact with a target in a target area downstream of the probe area.

26. The metrology system of clause 1, wherein the detection device is configured to detect light generated at a plurality of distinct wavelengths at a rate as fast as or faster than the rate at which the target passes through the probe area, and the control device is configured to perform analysis on the target. It is configured to effect adjustments to one or more characteristics associated with the target on which it is based.

27. The metrology system of clause 26, wherein the control device is configured to adjust one or more characteristics associated with the target, wherein the control device directs the operating light source to one or more operating light beams that interact with the target in a target area downstream of the probe area. and configured to command adjustment of the pointing of an X, Y, Z coordinate system, wherein the target axial path extends predominantly along the is about the Z axis.

28. Extreme ultraviolet (EUV) optical systems

a target supply device configured to form a flow of targets toward the target area, each target moving along a target axial path extending primarily along the X axis of the X, Y, Z coordinate system;

an actuating optical source configured to generate one or more actuating light beams directed to a target area, wherein the at least one actuating light beam is configured to interact with the target to form a modified target; and

Measurement system: includes,

The measurement system is

an optical device configured to generate an optical probe propagating along a probe optical axis intersecting the target axial path in the probe area;

A detection device configured to detect light generated at a plurality of distinct wavelengths, each wavelength being associated with a distinct position along the Generated from interactions in the probe area between targets moving along -; and

A control device in communication with the detection device, configured to analyze the detected light and determine position information associated with the target along the X-transverse axis of the X, Y, Z coordinate system.

29. The EUV optical system of clause 28, wherein the one or more actuating light beams comprises: a first amplified light beam configured to interact with the target to modify the shape and movement of the target and thereby form a modified target, and the modified target; and a second amplifying light beam configured to interact and transform the target modified thereby into a plasma that emits extreme ultraviolet light.

30. The measurement system is,

an optical device configured to generate an optical probe propagating along a probe optical axis intersecting a target axial path in the probe area, the target axial path extending primarily along the X axis of the X, Y, Z coordinate system;

A detection device configured to detect light generated at a plurality of distinct wavelengths, each wavelength being associated with a distinct position along the Generated from interactions in the probe area between targets moving along -; and

A control device in communication with the detection device, configured to analyze the detected light and determine position information associated with the target along the X-transverse axis of the X, Y, Z coordinate system.

31. In the metrology system of clause 30, the optical probe is a broadband optical probe.

32. In the metrology system of clause 30, the control device is configured to determine, on the basis of analysis of the detected light, positional information about the target along the X axis of the X, Y, Z coordinate system.

Other implementation forms are within the scope of the claims.

Claims (32)

In metrology systems:
an optical device configured to generate an optical probe comprising a plurality of distinct wavelengths of light, the optical probe comprising the distinct wavelengths of light propagating along a probe optical axis intersecting a target axial path in the probe area;
a detection device configured to detect light generated at the plurality of distinct wavelengths, the generated light resulting from interaction in the probe area between the optical probe and a target moving along the target axial path; and
A metrology system comprising a control device in communication with the detection device and configured to analyze the detected light and adjust one or more characteristics associated with one or more of the target and the target axial path based on the analysis. 2. The optical device of claim 1, wherein the optical device comprises one or more optical sources configured as the optical probe to generate a plurality of probing light beams, each probing light beam propagating along an optical axis of the probe intersecting the target axial path. A metrology system where each probing light beam has a distinct central wavelength. 3. The metrology system of claim 2, wherein each probing light beam having a distinct central wavelength is focused at a distinct location along the probe optical axis and within the probe area. 2. The optical device of claim 1, wherein the optical device comprises one or more optical sources configured as the optical probe to generate a probing light beam, the probing light beam propagating along an optical axis of the probe intersecting the target axial path, and A metrology system wherein the probing light beam is defined by a continuous spectrum of central wavelengths. 2. The metrology system of claim 1, wherein the optical probe has separate focal points along the probe optical axis and within the probe area. 6. The method of claim 5, wherein the metrology system further comprises cylindrical focusing optics in the path of the optical probe, wherein the cylindrical focusing optics serve as an optical curtain of the optical probe along a direction perpendicular to the probe optical axis. A measurement system configured to form a. 2. The metrology system of claim 1, wherein the optical probe is collimated along the probe optical axis or imaged in the probe area. 2. The metrology system of claim 1, wherein the detection device includes a plurality of detectors, each detector configured to detect light generated from an interaction between a respective probing light beam of the optical probe and the target. 9. The metrology system of claim 8, wherein each detector is configured to detect a portion of each probing light beam incident on the target. 10. The method of claim 9, wherein each detector is configured to detect a portion of the respective probing light beam incident on the target, such that each detector detects a portion of the respective probing light beam that is reflected or scattered from the target. A measurement system comprising: 9. The metrology system of claim 8, wherein each detector is configured to detect generated light having a wavelength distinct from the wavelength of the generated light detected by the remaining detectors. 2. The metrology system of claim 1, wherein the detection device is configured to distinguish light produced between each of the distinct wavelengths. 2. The metrology system of claim 1, wherein the generated light travels along a path that is distinct from the probe optical axis and also distinct from the target axial path. 2. The method of claim 1, wherein the generated light travels along a path parallel to an actuation axis, the actuation axis being defined by a direction in which the one or more actuating light beams move, and the one or more actuating light beams are positioned in the probe area. A metrology system that interacts with a target in a downstream target area. 15. The metrology system of claim 14, wherein the generated light is a portion of the probe light beam reflected back from the target along the actuation axis. 16. The metrology system of claim 15, wherein the generated light interacts with at least a portion of the same optical system with which the one or more actuating light beams interact. 2. The metrology system of claim 1, wherein along the target axial path, the probe area is upstream of a target area where the target interacts with one or more actuating light beams. 18. The metrology system of claim 17, wherein the target axial path extends at least along the X axis and the probe optical axis is not parallel to the X axis. 19. The metrology system of claim 18, wherein the control device is configured to determine the position of the target along a Y direction perpendicular to the X axis. 20. The metrology system of claim 19, wherein the probe optical axis is parallel to the Y axis and the operating light beam moves generally along the Z axis. 21. The metrology system of claim 20, wherein the plurality of wavelengths of light have a range such that the wavelength of light changes along the Y axis. 20. The metrology system of claim 19, wherein the probe optical axis is perpendicular to the Y axis. 23. The metrology system of claim 22, wherein the plurality of wavelengths of light are extended such that the wavelengths of the light vary along the Y axis. 18. The method of claim 17, wherein the at least one actuating light beam comprises: a first amplified light beam configured to interact with the target to modify the shape and movement of the target and thereby form a modified target; and A metrology system comprising a second amplified light beam configured to interact thereby converting the modified target into a plasma that emits extreme ultraviolet light. 2. The method of claim 1, wherein the control device is configured to adjust one or more characteristics associated with one or more of the target and the target axial path:
wherein the control device is configured to instruct a target material supply to adjust one or more aspects related to creation of the target; and
wherein the control device is configured to instruct the actuating light source to adjust one or more aspects related to the generation of one or more actuating light beams that interact with the target in a target region downstream of the probe region.
A metrology system that includes one or more of the following: 2. The method of claim 1, wherein the detection device is configured to detect light generated at the plurality of distinct wavelengths at a rate as fast as or faster than the rate at which a target passes through the probe area, and wherein the control device A metrology system configured to effect adjustments to one or more characteristics associated with the target on which the analysis is based. 27. The method of claim 26, wherein the control device is configured to adjust one or more characteristics associated with the target, wherein the control device provides an actuation light source, one or more actuation lights interacting with the target in a target area downstream of the probe area. and configured to command adjustment of the pointing of the beam, wherein the adjustment of the pointing is relative to the Z axis of an X, Y, Z coordinate system, wherein the target axial path extends predominantly along the A metrology system aligned with the Y axis or aligned with the Z axis. An extreme ultraviolet (EUV) optical system, comprising: a target supply device configured to form a flow of targets directed to a target area, each target moving along a target axial path extending primarily along the X axis of the X, Y, Z coordinate system; ;
an actuating optical source configured to generate one or more actuating light beams directed to a target area, wherein the at least one actuating light beam is configured to interact with the target to form a modified target; and
Measurement system: includes,
The measurement system is
an optical device configured to generate an optical probe propagating along a probe optical axis intersecting the target axial path in the probe area;
A detection device configured to detect light generated at a plurality of distinct wavelengths, each wavelength being associated with a distinct position along the resulting from interactions in the probe area between targets moving along the target axial path; and
An EUV optical system comprising: a control device in communication with the detection device, the control device configured to analyze the detected light and determine position information associated with the target along the X-transverse axis of the X, Y, Z coordinate system; . 29. The method of claim 28, wherein the at least one actuating light beam comprises: a first amplified light beam configured to interact with the target to modify the shape and movement of the target and thereby form a modified target; and an EUV optical system comprising: a second amplified light beam configured to interact thereby converting the modified target into a plasma that emits extreme ultraviolet light. In metrology systems:
an optical device configured to generate an optical probe propagating along a probe optical axis that intersects the target axial path in the probe area, the target axial path extending primarily along the X axis of the X, Y, Z coordinate system;
A detection device configured to detect light generated at a plurality of distinct wavelengths, each wavelength being associated with a distinct position along the resulting from interactions in the probe area between targets moving along the target axial path; and
A control device in communication with the detection device, the control device configured to analyze the detected light and determine position information associated with the target along the X-transverse axis of the X, Y, Z coordinate system. 31. The metrology system of claim 30, wherein the optical probe is a broadband optical probe. 31. The metrology system of claim 30, wherein the control device is configured to determine position information associated with the target along the X axis of the X, Y, Z coordinate system based on analysis of detected light.