System for path compensation with moving objective lens

Abstract

Disclosed is a mirror group having a first mirror, a second mirror, and a movable table, the mirror group being mounted to the movable table to move the first mirror and the second mirror together with the movable table. The first mirror is configured to receive a beam at a first angle to an axis of the set of mirrors, and the second mirror is configured to provide a beam at a second angle to the axis of the set of mirrors, the beam providing an output after being reflected by the second mirror. Movement of the mirror set parallel to the axis causes parallel displacement of the output along the beam, and movement of the mirror set perpendicular to the axis causes vertical displacement of the output perpendicular to the beam.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to U.S. application 63 / 410,700, filed on September 28, 2022, and incorporated herein by reference in its entirety. Technical Field

[0003] The description herein generally relates to optical systems for measurement or metrology. More specifically, the disclosure includes an apparatus for compensating for changes in a beam path in a system with a moving objective lens. Background Art

[0004] Lithographic projection apparatus may, for example, be used in the manufacture of integrated circuits (ICs). In this case, a patterning device (e.g. a mask) may contain or provide patterns corresponding to the various layers of the IC (a "design layout"), and the pattern may be transferred to a target portion (e.g. comprising one or more dies) on a substrate (e.g. a silicon wafer) which has been coated with a layer of radiation-sensitive material ("resist"), such as by irradiating the target portion through the pattern on the patterning device. Typically, a single substrate contains a plurality of adjacent target portions to which the pattern is transferred successively, one at a time, by the lithographic projection apparatus. In one type of lithographic projection apparatus, the entire pattern on the patterning device is transferred to one target portion at a time; such an apparatus may also be referred to as a stepper. In an alternative apparatus, a stepper-scan apparatus may cause the projection beam to be scanned over the patterning device along a given reference direction (the "scanning" direction) while synchronously moving the substrate parallel or antiparallel to the reference direction. Different portions of the pattern on the patterning device are progressively transferred to one target portion. Typically, since the lithographic projection apparatus will have a demagnification factor M (eg 4), the speed F at which the substrate is moved will be 1 / M times that of the projection beam scanning patterning device. More information on lithographic apparatus can be found, for example, in US 6,046,792, which is incorporated herein by reference.

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

[0006] Therefore, manufacturing devices such as semiconductor devices typically involves processing a substrate (e.g., a semiconductor wafer) using a number of fabrication processes to form various features and multiple layers of the device. Such layers and features are typically manufactured and processed using, for example, deposition, lithography, etching, chemical mechanical polishing, and ion implantation. Multiple devices can be fabricated on multiple dies on a substrate and then separated into individual 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 lithography apparatus to transfer the pattern on the pattern forming device to the substrate, and typically but optionally, involves one or more associated pattern processing steps, such as resist development by a developing apparatus, baking of the substrate using a baking tool, etching using the pattern using an etching apparatus, and the like.

[0007] As mentioned, photolithography is a central step in the fabrication of devices such as ICs, where patterns formed on a substrate define the functional elements of devices such as microprocessors, memory chips, etc. Similar photolithography techniques are also used in the formation of flat panel displays, microelectromechanical systems (MEMS), and other devices.

[0008] As semiconductor manufacturing processes continue to advance, following a trend known as "Moore's Law," the size of functional elements has been continuously reduced, while the number of functional elements (such as transistors) per device has steadily increased for decades. At the current state of the art, the layers of a device are manufactured using a lithography projection device that projects a design layout onto a substrate using illumination from a deep ultraviolet illumination source, thereby creating individual functional elements with 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 may be referred to as low-k1 lithography, according to the resolution formula CD=k1×λ / NA, where λ is the wavelength of the radiation employed (e.g., 248 nm or 193 nm), NA is the numerical aperture of the projection optics in the lithographic projection apparatus, CD is the "critical dimension" (usually the smallest printed feature size), and k1 is an empirical resolution factor. In general, the smaller the k1, the more difficult it is to reproduce a pattern on a substrate that is similar in shape and size to that planned by the designer to achieve specific electrical functionality and performance. To overcome these difficulties, complex fine-tuning steps are applied to the lithographic projection apparatus, the design layout, or the patterning device. For example, these include, but are not limited to, optimization of NA and optical coherence settings, customized illumination schemes, the use of phase-shifting patterning devices, optical proximity correction (OPC, sometimes also referred to as "optical and process correction") in the design layout, or other methods generally defined as "resolution enhancement techniques" (RET). The term "projection optics" as used herein should be broadly interpreted to cover various types of optical systems, including, for example, refractive optics, reflective optics, aperture stops, and reflective-refractive optics. The term "projection optics" may also include components that operate according to any of these design types for collectively or individually directing, shaping, or controlling a projection beam of radiation. The term "projection optics" may include any optical component in a lithographic projection apparatus, regardless of where the optical component is located in the optical path of the lithographic projection apparatus. 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. Summary of the invention

[0010] A system is disclosed, the system comprising a reflector assembly and a movable stage, the reflector assembly comprising a first reflector, a second reflector, the reflector assembly being mounted to the movable stage so that the first reflector and the second reflector move together with the movable stage. The first reflector is configured to receive a beam at a first angle to the axis of the reflector assembly. The second reflector is configured to provide the beam at a second angle to the axis of the reflector assembly, the beam providing an output after being reflected by the second reflector. Movement of the reflector assembly parallel to the axis causes parallel displacement of the output along the beam, and movement of the reflector assembly perpendicular to the axis causes vertical displacement of the output perpendicular to the beam.

[0011] In some embodiments, the beam is a light beam from a light source in an optical scanning device, and the output may be a focus of the light beam.

[0012] In some embodiments, the system may further include an objective lens for receiving the output and configured to move with the movable stage, wherein during movement of the movable stage and the objective lens, the output remains stationary relative to the objective lens.

[0013] In some embodiments, the angle ratio as the ratio between the first angle and the second angle determines the movement ratio of the movable stage, which is the ratio of the movement at the output to the movement at the movable stage. The angle between the input and the output can be 120 degrees, so that the ratio is 1.

[0014] In some embodiments, the system may include an objective lens for receiving the output, the objective lens being configured to move in a first direction with the movable stage. The system may also include a first static mirror configured to direct the beam to the objective lens, wherein moving the movable stage and the objective lens along the first direction maintains the position of the output at the objective lens along the second direction.

[0015] In some embodiments, the objective lens may be mechanically coupled to the movable stage or electronically controlled to move in correspondence with movement of the movable stage. Movement of the movable stage in the second direction may cause corresponding movement of the output relative to the objective lens.

[0016] In some embodiments, the system may further include an objective lens for receiving the output, the objective lens being configured to move in the first direction and / or the second direction with the movable stage. The first static reflector may be configured to redirect the beam to the objective lens, and the second static reflector may be configured to direct the beam to the first static reflector. The movable stage and the objective lens are moved to maintain the position of the output at the objective lens by maintaining the displacement along the first direction and along the second direction.

[0017] In some embodiments, the system may further include: a second static reflector, the second static reflector configured to direct the beam to the reflector group; and a second reflector group, the second reflector group oriented perpendicular to and beyond the plane of the reflector group, and the second reflector group configured to direct the beam from the second reflector group to the reflector group. There may be a second movable stage and a third static reflector, the second reflector group being mounted to the second movable stage, the third static reflector configured to direct the beam from the second reflector group to the second static reflector, wherein moving the second reflector group in a first direction allows adjustment of the output in the first direction, moving the second reflector group in a second direction allows adjustment of the output in the second direction, and moving the second reflector group in a third direction does not change the positioning of the output in the third direction.

[0018] In some embodiments, the system is configured to move the second mirror group and the objective lens relative to the mirror group in a second direction, thereby moving the output along the second direction.

[0019] In some embodiments, the objective lens is further configured to move in a second direction independently of the mirror group, wherein maintaining a displacement between the second mirror group and the objective lens in the second direction maintains a position of the output relative to the objective lens in the second direction.

[0020] In some embodiments, the system further comprises an objective lens for receiving the output, the objective lens being configured to move with the movable stage to maintain the same displacement between the objective lens and the movable stage in both the first direction and the third direction. The system may further comprise a first static mirror configured to direct the beam to the objective lens, a second static mirror configured to direct the beam to the first static mirror, and a folding mirror coupled to the movable stage and configured to rotate the beam to be along the second direction, wherein moving the movable stage and the objective lens to maintain the displacement maintains the position of the output at the objective lens along the second direction. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate certain aspects of the subject matter disclosed herein and, together with the description, help explain some principles associated with the disclosed implementations.

[0022] Figure 1 is a schematic diagram of a dual objective lens measurement system with a movable objective lens according to an embodiment of the present disclosure.

[0023] Figure 2 is a schematic diagram of a metrology system having a mirror set for directing light to / from an objective lens according to an embodiment of the present disclosure.

[0024] Figure 3 is a schematic diagram of a mirror group for compensating for movement of a movable stage according to an embodiment of the present disclosure.

[0025] Figure 4 is a schematic diagram of a mirror group that compensates for the movement of a movable stage and delivers a beam to an objective lens according to an embodiment of the present disclosure.

[0026] FIG. 5A to FIG. 5C is a schematic diagram of alternative configurations of reflector assemblies according to various embodiments of the present disclosure.

[0027] Figure 6 is a schematic diagram of a mirror assembly that allows movement with two degrees of freedom according to an embodiment of the present disclosure.

[0028] Figure 7is a schematic diagram of a plurality of reflector groups that allow movement perpendicular to the plane of one of the reflector groups according to an embodiment of the present disclosure.

[0029] Figure 8 is a schematic diagram of a mirror assembly including a tunable mirror for an objective lens according to an embodiment of the present disclosure.

[0030] Fig. 9 is a block diagram of an example computer system according to an embodiment of the present disclosure.

[0031] Fig.10 is a schematic diagram of a lithography projection apparatus according to an embodiment of the present disclosure.

[0032] Fig.11 is a schematic diagram of another lithography projection apparatus according to an embodiment of the present disclosure.

[0033] Fig.12 is a detailed view of a lithographic projection apparatus according to an embodiment of the present disclosure.

[0034] Fig.13 is a detailed view of a source collector module of a lithographic projection apparatus according to an embodiment of the present disclosure. DETAILED DESCRIPTION

[0035] Metrology systems (e.g., electron beam, optical, etc.) can be used to measure and / or characterize printed products (e.g., semiconductor chip wafers) or other manufactured components. For example, during or after the manufacture of wafers for semiconductor processors, memory, etc., printed or etched features on the wafer can be measured to determine how well the product matches the target pattern. These measurements can include measuring aspects such as critical dimension (CD), overlay, edge placement error (EPE). The present disclosure is generally directed to measurements made using an optical metrology system that provides light to the surface of a target product and then detects and analyzes the light to generate an image of the target for further analysis.

[0036] Figure 1 is a schematic diagram of a dual objective lens measurement system with a movable objective lens according to an embodiment of the present disclosure. Some measurement systems may allow for parallel measurement of multiple targets (eg, wafers) using two separate objective lenses. Figure 1As shown, the metrology system 100 may include a source / sensor 130, the source / sensor 130 illumination light is split between two objective lenses 110, 112. The architecture may have at least one objective lens that can be moved, for example, to be able to measure targets 120 separated by different distances, for example due to being separate targets, or due to misalignment between two wafers being measured simultaneously. The split light may be directed through two mirror groups 140, 142, wherein at least a portion of one of the mirror groups (e.g., mirror group 140) is movable with the objective lens 110.

[0037] Figure 2 is a schematic diagram of a metrology system having a mirror set for directing light to / from an objective lens according to an embodiment of the present disclosure. Figure 2 Including about Figure 1 Many of the features described herein (e.g., objective lens 110, target 120, source / sensor 130). Figure 2 As shown in the simplified example in , the present disclosure provides many embodiments that allow a light beam 250 from a source / sensor 130 to be delivered to an objective lens 110. In various embodiments, this can be achieved by moving the objective lens 110 relative to some components of the system, but leaving the objective lens 110 stationary relative to at least some portion of a movable stage 210 that can hold a mirror group 220. For example, the objective lens 110 can be fixed to the movable stage 210 so that the objective lens 110 and the movable stage 210 move together, or in other embodiments, the objective lens 110 can be independently controlled to move synchronously with some portion of the mirror group 220.

[0038] Figure 3 is a schematic diagram of a mirror group for compensating for movement of a movable stage according to an embodiment of the present disclosure. Figure 3 A system is depicted that is insensitive (also referred to herein as "compensated") to movement of the movable stage in certain directions due to the geometry of the example mirror 222 in the mirror set 220. Such a system can cause a displaced light beam 330 (e.g., displaced relative to the movable stage) to reach a target and / or cause light from the target to return to the sensor along the same path. In some embodiments, the beam can be from an optical scanning device or a metrology system (such as Figure 1 and 2 The light beam of the light source in FIG. Figure 3The depicted system includes a reflector assembly 320 having a first reflector 322 (here used to receive a beam 330 illustrated by a dashed line) and a second reflector 324 (here shown to provide the beam 330 after reflection from the first reflector 322 and the second reflector 324). There may be a movable stage 310 to which the reflector assembly 320 may be mounted so that the first reflector 322 and the second reflector 324 move with the movable stage 310. The movable stage may be, for example, an optical table, a plate, or any other object to which the reflectors / optics may be mounted and may be configured to move in one or more directions, for example, using a motor, on a track or rail, using a belt, using a piezoelectric transducer, etc. As shown, the first reflector 322 may be configured to receive the beam 330 at a first angle 340 to an axis 342 of the reflector assembly. The first angle 340 may be any angle between 0 and 180 degrees, for example, +75 degrees, 60 degrees, 45 degrees, 30 degrees, 15 degrees. Similarly, the second reflector 324 can be configured to provide a beam 330 at a second angle 344 with respect to an axis 342 of the reflector stack 320, which provides an output 350 (e.g., a focus, a spot, etc. of the beam) after reflection by the second reflector 324. The output 350 can be located at any point along the beam path after the last reflector in the reflector stack.

[0039] In general, movement of the mirror group 320 parallel to the axis 342 (e.g., parallel movement 360) can cause a parallel displacement 362 of the output 350 along the beam (i.e., parallel to the beam direction at the target). For example, as shown, movement along the Y direction (along the axis 342) is used to shorten / lengthen the beam path without changing any reflection angles. In the example where the output is the focus of the beam, this has the effect of moving the focus but not perpendicular to the beam path. Similarly, movement 370 of the mirror group 320 perpendicular to the axis 342 can cause a vertical displacement 372 of the output 350 perpendicular to the beam. The angle ratio (which can be the ratio between the first angle 340 and the second angle 344) can determine the movement ratio of the movable stage 310. The movement ratio is the ratio of the amount of movement of the output to the amount of movement of the movable stage. Specifically, in embodiments where the first angle 340 and the second angle 344 are the same, the ratio may vary from 1.73 when both angles are 30 degrees, to 1.0 when both angles are 60 degrees, to 0.52 when both angles are 75 degrees, and so on. For example, if both angles are 60 degrees, then a 1 mm parallel translation 360 would result in a 1 mm parallel displacement 362 of the output 350. While in some embodiments, ratios other than 1.0 may be useful, in most embodiments, the angle between the input and output (i.e., the sum of the first angle 340 and the second angle 344) is 120 degrees, resulting in a ratio of 1.0. In embodiments where the angles are different, this may result in a compound motion where, for example, in response to the parallel translation 360, the output 350 may exhibit a parallel displacement 362, but may also exhibit a perpendicular displacement 372.

[0040] Despite Figure 3 Not shown, but in any embodiment of the present invention, the system may include an objective lens for receiving the output and configured to move with the movable stage. Also as shown in many embodiments of the present invention, during the movement of the movable stage and the objective lens, the output may remain stationary relative to the objective lens. As previously described, any objective lens in the present invention may be configured to move with the movable stage by being mechanically coupled to the movable stage, or may be independently (e.g., electronically) controlled to move corresponding to the movement of the movable stage. As used herein, "mechanical coupling" or simply "coupling" means that there is a rigid connection (e.g., the objective lens is fastened to the movable stage in some way). Although the objective lens may be a lens for focusing on a wafer or other target, the objective lens may be any other optical component (such as a lens, a reflector, etc.) or any component that may require a beam to be located at a specific focal position. Moreover, although the objective lens is listed as included in many embodiments, the present disclosure contemplates that the objective lens does not need to be included in the specific physical system of any embodiment. For example, some embodiments may only include a reflector system, in which the objective lens, the movable stage, etc. are supplied separately to be used as described herein.

[0041] Various embodiments herein are described with reference to an orthogonal XYZ coordinate system. This is for explanation purposes only, and therefore any embodiment does not require any particular orientation. The X direction is referred to herein as the "first direction" (and may be positive or negative), and the Z direction is referred to herein as the "second direction" (and may be positive or negative). Some embodiments may include a Y direction, which is referred to herein as the "third direction" (and may be positive or negative).

[0042] Figure 4 is a schematic diagram of a mirror set that compensates for the movement of a movable stage and delivers a beam to an objective lens according to an embodiment of the present disclosure. The mirror set is depicted as being located in the XZ plane. Figure 4 Also similar to Figure 3 , in which many elements are reproduced. However, Figure 4 The depicted embodiment also includes an objective lens 480 for receiving the output 350. The objective lens 480 can be configured to move along the first direction with the movable stage 310, such as by mechanical coupling or by electronic control in a manner corresponding to the movement of the movable stage 310. Some embodiments can include a first static mirror 490 configured to direct the beam 330 to the objective lens 480. As used herein, the term "static" means "stationary relative to the input beam of light" (e.g., stationary relative to the light source, the last optical component before the beam reaches the mirror group, etc.). Although in some embodiments the static mirror may be movable, as used herein, any static mirror is considered to remain in place relative to any movement of the movable stage.

[0043] Moving the movable stage and objective lens 480 along a first direction (e.g., the X direction) maintains the position of the output 350 at the objective lens 480 along a second direction (e.g., the Z direction) as the first static mirror 490 substantially redirects the output 350 to the objective lens 480. Similarly, in some embodiments, movement of the movable stage 310 in the second direction can cause a corresponding movement of the output 350 relative to the objective lens 480.

[0044] FIG. 5A to FIG. 5C Schematic diagram of alternative configurations of reflector assemblies according to various embodiments of the present disclosure. These alternative configurations perform the same Figure 4 However, it can be seen that the various mirrors and movable stages in the mirror assembly have different geometries. The element numbers are from Figure 4 The corresponding elements of FIG. 5 are reproduced, but with the name (A, B or C) of FIG. 5 added (e.g. Figure 5A The movable stage 310A in FIG. Figure 4 The movable stage 310 in FIG.

[0045] Figure 6 is a schematic diagram of a mirror assembly that allows movement with two degrees of freedom according to an embodiment of the present disclosure. This embodiment is similar to Figure 3 , but in particular, the mirror set 320 is inverted, and static mirrors 690, 692 and an objective lens 680 are added. The objective lens 680 can receive the output 350, and the objective lens 680 is configured to move in a first direction (e.g., X direction) and / or a second direction (e.g., Z direction) with the movable stage 310. The system can also include a first static mirror 690 configured to redirect the beam 330 to the objective lens 680 and a second static mirror 692 configured to direct the beam 330 to the first static mirror 690.

[0046] The system can be configured so that moving the movable stage 310 and the objective lens 680 to maintain displacement along the first direction and along the second direction maintains the position of the output 350 at the objective lens 680. As used herein, the phrase "maintaining displacement" means that certain elements of the system (e.g., the movable stage 310 and the objective lens 680) move together, such as via mechanical coupling or independent but synchronized control. This also means that the movable stage 310 and the objective lens 680 can move freely in the XZ plane, as shown, and the output 350 remains at the same position in the objective lens 680.

[0047] Figure 7 is a schematic diagram of a plurality of reflector groups that allow movement perpendicular to the plane of one of the reflector groups according to an embodiment of the present disclosure. Figure 7 An illustration 702 is included that depicts a three-dimensional view of an embodiment having multiple mirror groups arranged in orthogonal planes. An illustration 704 that illustrates components in the YZ plane and an illustration 706 that illustrates components in the XZ plane are also shown. By including another mirror group in an orthogonal plane (e.g., the YZ plane), which is thus configured to allow the objective lens to move in the Y direction, the depicted system is simplified. Figure 4 By folding the diagram 704 to a 90 degree "off-page" similar to the situation depicted in the diagram 702, it can also be understood that Figure 7 Furthermore, the bundle 330 exiting diagram 704 is the input bundle in diagram 706 .

[0048] Apart from Figure 4In addition to the depicted elements (some of which are reproduced in illustrations 702, 704, and 706), some embodiments may further include a second static mirror 792 configured to direct beam 330 to mirror group 320 (in illustration 706). Also shown is a second mirror group 720 (in illustration 704), which is oriented perpendicular to and out of the plane of mirror group 320 and is configured to direct beam 330 from second mirror group 720 to mirror group 320. A second movable stage 710 is shown to which second mirror group 720 may be mounted. Second movable stage 710 and second mirror group 720 may be similar to Figure 4 The movable stage and mirror group of FIG. 720 are shown in FIG. 721 , but in this embodiment, the second mirror group 720 is inverted. There may also be a third static mirror 794 configured to direct the beam 330 from the second mirror group 720 to the second static mirror 792. Therefore, Figure 7 The embodiment is configured such that: moving the second reflector group 720 in the second direction allows the output 350 to be adjusted in the second direction, moving the first reflector group 720 in the third direction allows the output 350 to be adjusted in the third direction, and moving the second reflector group 720 in the first direction does not change the positioning of the output 350 in the first direction. Similarly, moving the first reflector group 320 in the first direction allows the output 350 to be adjusted in the first direction, moving the first reflector group 320 in the second direction allows the output 350 to be adjusted in the second direction, and moving the first reflector group 320 in the third direction does not change the positioning of the output 350 in the third direction.

[0049] In some embodiments, the system can be configured to move the second mirror group 720 and the objective lens 480 in the second direction relative to the mirror group 320, thereby causing the output 350 to move along the second direction. In other embodiments, the mirror group 320 and the objective lens 480 can be moved in the second direction relative to the second mirror group 720, thereby also causing the output 350 to move along the second direction.

[0050] In some embodiments, the objective lens 480 can also be configured to move in the second direction independently of the mirror group. In such embodiments, maintaining the displacement between the second mirror group 720 and the objective lens 480 in the second direction maintains the position of the output 350 relative to the objective lens 480 in the second direction.

[0051] Figure 8 is a schematic diagram of a mirror assembly including a tunable mirror for an objective lens according to an embodiment of the present disclosure. Figure 8The embodiment depicts a mirror assembly that can have an objective lens oriented perpendicular to the plane of the mirror assembly. For example, the mirror assembly 320 can be mounted horizontally (e.g., in the XY plane) with the objective lens 480 oriented vertically (e.g., along Z). Figure 8 Also Figure 3 Based on the embodiment of the present invention, it may further include an objective lens 480 (similar to Figure 4 The objective lens 480 may be configured to move with the movable stage 310 to maintain the same displacement between the objective lens 480 and the movable stage 310 in both the first direction (e.g., in the X direction) and the third direction (e.g., along the Y direction). The system may also include a first static mirror 890 configured to direct the beam 330 to the objective lens 480 and a second static mirror 892 configured to direct the beam 330 to the first static mirror 890.

[0052] The system may also include a fold mirror 894 coupled to the movable stage 310 and configured to turn the beam 330 to be along a second direction (e.g., along Z). The fold mirror may be any type of mirror, but is described herein as "folding" because the fold mirror "folds" the beam from being in the XY plane as shown to being along Z (or any other direction in other embodiments). Thus, in such embodiments, moving the movable stage 310 and the objective lens 480 to maintain the displacement may maintain the position of the output 350 at the objective lens 480 along the second direction (e.g., along Z).

[0053] As mentioned previously, embodiments disclosed herein can improve measurement and / or metrology of devices such as those fabricated using photolithographic processes.An example of a photolithographic system that can be used with the disclosed embodiments is described below.

[0054] Fig. 9 is a block diagram of an example computer system CS according to an embodiment of the present disclosure.

[0055] The computer system CS comprises a bus BS or other communication mechanism for transferring information and a processor PRO (or multiple processors) coupled to the bus BS for processing information. The computer system CS also comprises a main memory MM, such as a random access memory (RAM) or other dynamic storage device, which is coupled 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 to be executed by the processor PRO. The computer system CS also comprises a read-only memory (ROM) ROM or other static storage device coupled to the bus BS for storing static information and instructions of the processor PRO. Storage devices SD such as magnetic disks or optical disks are provided and coupled to the bus BS for storing information and instructions.

[0056] The computer system CS can be coupled to a display DS via a bus BS, such as a cathode ray tube (CRT) or a flat panel or touch panel display, for displaying information to a computer user. An input device ID including alphanumeric keys and other keys is coupled to the bus BS for passing 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 passing direction information and command selections to the processor PRO and controlling cursor movement 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), allowing the device to specify a position in a plane. A touch panel (screen) display can also be used as an input device.

[0057] According to one embodiment, in response to the processor PRO executing one or more sequences of one or more instructions contained in the main memory MM, the part of one or more methods described herein can be executed by the computer system CS. Such instructions can be read into the main memory MM from another computer-readable medium (such as a storage device SD). The execution of the instruction sequence contained in the main memory MM prompts the processor PRO to perform the process steps described herein. One or more processors in a multi-processing arrangement can also be adopted to execute the instruction sequence contained in the main memory MM. In an alternative embodiment, a hard-wired circuit system can be used instead of a software instruction or in combination with a software instruction. Therefore, the description herein is not limited to any specific combination of hardware circuit system and software.

[0058] The term "computer-readable medium" used herein refers to any medium that participates in providing instructions to the processor PRO for execution. Such a medium can take many forms, including but not limited to non-volatile media, volatile media and transmission media. Non-volatile media include, for example, 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 that constitute 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 communications. Computer-readable media can be non-transient, such as floppy disks, foldable disks, hard disks, tapes, any other magnetic media, CD-ROMs, DVDs, any other optical media, punch cards, paper tapes, any other physical media with hole patterns, RAM, PROMs and EPROMs, flash EPROMs, any other memory chips or memory cartridges. Non-transient computer-readable media can have instructions recorded thereon. When executed by a computer, instructions can implement any feature described herein. Transient computer-readable media can include carriers or other propagating electromagnetic signals.

[0059] Various forms of computer-readable media may be involved in carrying 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 over 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 an infrared signal using an infrared transmitter. An infrared detector coupled to the bus BS may receive the data carried in the infrared signal and place the data on the bus BS. The bus BS carries the data to the main memory MM, from which the processor PRO retrieves and executes the instructions. Before or after execution by the processor PRO, the instructions received by the main memory MM may optionally be stored on a storage device SD.

[0060] The computer system CS may also include a communication interface CI coupled to the bus BS. The communication interface CI provides a bidirectional data communication coupling with a network link NDL connected to a local 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 with a corresponding type of telephone line. As another example, the communication interface CI may be a local area network (LAN) card to provide a data communication connection with 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 that carry digital data streams representing various types of information.

[0061] 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 the global packet data communication network (now generally called the "Internet" INT). The local network LAN (Internet) all use electrical signals, electromagnetic signals or optical signals that carry digital data streams. The signals through the various networks and the signals on the network data link NDL and through the communication interface CI (carrying digital data to and from the computer system CS) are exemplary forms of carrier waves that transport information.

[0062] 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 Internet example, the host computer HC can send the request code of the application program through the Internet INT, the network data link NDL, the local network LAN and the communication interface CI. For example, one such download application can provide all or part of the method described herein. The received code can be executed by the processor PRO when it 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.

[0063] Fig.10 is a schematic diagram of a lithography projection apparatus according to an embodiment of the present disclosure.

[0064] The lithographic projection apparatus may include an illumination system IL, a first stage MT, a second stage WT and a projection system PS.

[0065] The illumination system IL may condition the radiation beam B. In this particular case, the illumination system also includes a radiation source SO.

[0066] A first stage (eg patterning device table) MT may be provided with a patterning device holder to hold a patterning device MA (eg reticle) and connected to a first positioner to accurately position the patterning device relative to the object PS.

[0067] A second workpiece table (substrate table) WT may be provided with a substrate holder to hold a substrate W (eg a resist coated silicon wafer) and connected to a second positioner to accurately position the substrate relative to the item PS.

[0068] A projection system ("lens") PS (eg, a refractive, reflective or catadioptric optical system) may image the irradiated portion of the patterning device MA onto a target portion C of the substrate W (eg, comprising one or more dies).

[0069] As depicted herein, the device may be transmissive (i.e., having a transmissive patterning device). However, in general, it may also be reflective, for example (having a reflective patterning device). The device may employ different kinds of patterning devices than classical masks; examples include programmable mirror arrays or LCD matrices.

[0070] A source SO (e.g. a mercury lamp or an excimer laser, an LPP (laser produced plasma) EUV source) generates a radiation beam. This beam is fed into an illumination system (illuminator) IL, for example directly or after having passed through a conditioning device such as a beam expander Ex. The illuminator IL may comprise an adjustment device AD ​​for setting the outer and / or inner radial extent (commonly referred to as σ-outer and σ-inner, respectively) of the intensity distribution in the beam. In addition, it will typically comprise various other components, such as an integrator IN and a condenser CO. In this way, the beam B impinging on the patterning device MA has a desired uniformity and intensity distribution in its cross section.

[0071] In some embodiments, the source SO may be within the housing of the lithographic projection apparatus (e.g. this is typically the case when the source SO is a mercury lamp), but it may also be remote from the lithographic projection apparatus, the radiation beam it generates being introduced into the apparatus (e.g. with the aid of suitable directing mirrors); this latter scenario may be the case when the source SO is an excimer laser (e.g. based on KrF, ArF or F2 laser irradiation).

[0072] The beam PB may then intersect the patterning device MA, which is held on the patterning device table MT. After passing through the patterning device MA, the beam PB may pass through a lens PL, which focuses the beam B onto a target portion C of the substrate W. With the aid of a second positioning device (and an interferometric measurement device IF), the substrate table WT may be accurately moved, for example to position different target portions C in the path of the beam PB. Similarly, the first positioning device may be used to accurately position the patterning device MA relative to the path of the beam B, for example after mechanically retrieving the patterning device MA from a patterning device library or during a scan. Typically, movement of the stage MT, WT may be achieved with the aid of a long-stroke module (coarse positioning) and a short-stroke module (fine positioning). However, in the case of a stepper (as opposed to a step-and-scan tool), the patterning device table MT may be connected only to a short-stroke actuator, or may be fixed.

[0073] The depicted tool can be used in two different modes: a step mode and a scan mode. In the step mode, the patterning device table MT remains substantially stationary and the entire patterning device image is projected onto a target portion C at one time (i.e. a single "flash"). The substrate table WT can be shifted in the x and / or y direction so that a different target portion C can be irradiated by the beam PB.

[0074] In scan mode, essentially the same scenario applies, except that a given target portion C is not exposed in a single "flash". Instead, the patterning device table MT can be moved in a given direction (the so-called "scanning direction", e.g. the y-direction) at a speed v, so as to cause the projection beam B to scan over the patterning device image; concurrently, the substrate table WT is simultaneously moved in the same or opposite direction at a speed V=Mv, where M is the magnification of the lens PL (typically M=1 / 4 or 1 / 5). In this way, a relatively large target portion C can be exposed without having to sacrifice resolution.

[0075] Fig.11 is a schematic diagram of another lithographic projection apparatus (LPA) according to an embodiment of the present disclosure.

[0076] The LPA may comprise a source collector module SO, an illumination system (illuminator IL) configured to condition a radiation beam B (eg EUV radiation), a support structure MT, a substrate table WT and a projection system PS.

[0077] The support structure (e.g., patterning device table) MT may be constructed to support a patterning device (e.g., mask or reticle) MA and be connected to a first positioner PM configured to accurately position the patterning device;

[0078] The substrate table (eg, wafer stage) WT may be configured to hold a substrate (eg, a resist-coated wafer) W and be connected to a second positioner PW configured to accurately position the substrate.

[0079] The projection system (eg, a reflective projection system) PS may be configured to project the pattern imparted to the radiation beam B by the patterning device MA onto a target portion C of the substrate W (eg, comprising one or more dies).

[0080] As depicted here, the LPA can be reflective (e.g., using a reflective patterning device). Note that because most materials are absorptive in the EUV wavelength range, the patterning device can have a multilayer reflector that includes multiple stacks of, for example, molybdenum and silicon. In one example, the multilayer reflector has 40 layer pairs of molybdenum and silicon, where each layer is a quarter wavelength thick. Even smaller wavelengths can be produced with x-ray lithography. Since most materials are absorptive at both EUV and x-ray wavelengths, a thin sheet of patterned absorbing material on the patterning device topography (e.g., a TaN absorber on top of a multilayer reflector) defines where features will be printed (positive resist) or not (negative resist).

[0081] The illuminator IL may receive an extreme ultraviolet radiation beam from a source collector module SO. Methods for generating EUV radiation include, but are not necessarily limited to, converting a material into a plasma state having at least one element (e.g., xenon, lithium, or tin) having one or more emission lines in the EUV range. In one such method, a fuel (such as a droplet, stream, or cluster of a material having a line-emitting element) may be generated by irradiating the fuel with a laser beam, and the plasma is generally referred to as a laser produced plasma ("LPP"). The source collector module SO may be part of an EUV radiation system that includes a laser for providing a laser beam to excite the fuel. The resulting plasma emits output radiation, such as EUV radiation, which is collected using a radiation collector disposed in the source collector module. For example, when a CO2 laser is used to provide a laser beam for fuel excitation, the laser and the source collector module may be separate entities.

[0082] In this case, the laser may not be considered to form part of the lithographic apparatus, and the radiation beam may be delivered from the laser to the source collector module with the aid of a beam delivery system including, for example, suitable directing mirrors and / or a beam expander. In other cases, the source may be an integrated part of the source collector module, for example when the source is a discharge produced plasma EUV generator, often referred to as a DPP source.

[0083] The illuminator IL may include an adjuster for adjusting the angular intensity distribution of the radiation beam. Typically, at least the outer and / or inner radial extent (generally referred to as σ-outer and σ-inner, respectively) of the intensity distribution in a pupil plane of the illuminator may be adjusted. In addition, the illuminator IL may include various other components, such as a facet field and a pupil mirror arrangement. The illuminator may be used to adjust the radiation beam to have a desired uniformity and intensity distribution in its cross-section.

[0084] A radiation beam B may be incident on and patterned by a patterning device (e.g. a mask) MA, which is held on a support structure (e.g. a patterning device table) MT. After being reflected from the patterning device (e.g. a mask) MA, the radiation beam B passes through a projection system PS, which focuses the beam onto a target portion C of a substrate W. With the aid of a second positioner PW and a position sensor PS2 (e.g. an interferometer, a linear encoder or a capacitive sensor), the substrate table WT may be accurately moved, for example to position different target portions C in the path of the radiation beam B. Similarly, a first positioner PM and a further position sensor PS1 may be used to accurately position the patterning device (e.g. a mask) MA relative to the path of the radiation beam B. The patterning device (e.g. a mask) MA and the substrate W may be aligned using patterning device alignment marks M1, M2 and substrate alignment marks P1, P2.

[0085] The depicted device LPA can be used in at least one of the following modes: a stepping mode, a scanning mode and a stationary mode.

[0086] In step mode, the support structure (e.g. patterning device table) MT and the substrate table WT remain substantially stationary while the entire pattern imparted to the radiation beam is projected at one time (i.e. a single static exposure) onto a target portion C. The substrate table WT is then shifted in the X and / or Y direction so that a different target portion C can be exposed.

[0087] In scan mode, the support structure (e.g. patterning device table) MT and substrate table WT are scanned synchronously as a pattern imparted to the radiation beam is projected onto a target portion C (i.e. a single dynamic exposure). The velocity and direction of the substrate table WT relative to the support structure (e.g. patterning device table) MT may be determined by the (de-)magnification and image reversal characteristics of the projection system PS.

[0088] In stationary mode, the support structure (e.g. patterning device table) MT remains essentially stationary, thereby holding the programmable patterning device, and the substrate table WT is moved or scanned, while a pattern imparted to the radiation beam is projected onto a target portion C. In this mode, a pulsed radiation source is typically used, 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, such as a programmable mirror array.

[0089] Fig.12 is a detailed view of a lithographic projection apparatus according to an embodiment of the present disclosure.

[0090] As shown, the LPA may include a source collector module SO, an illumination system IL, and a projection system PS. The source collector module SO is constructed and arranged so that a vacuum environment can be maintained in the closed structure ES of the source collector module SO. A plasma source that can be generated by a discharge forms an EUV radiation emitting thermal plasma HP. EUV radiation can be generated by a gas or vapor, such as xenon, lithium vapor, or tin vapor, wherein the thermal plasma HP is generated to emit radiation in the EUV range of the electromagnetic spectrum. The thermal plasma HP is generated by, for example, a discharge that results in at least partially ionized plasma. In order to efficiently generate radiation, a partial pressure of, for example, Xe, Li, Sn vapor, or any other suitable gas or vapor of 10 Pa may be required. In an embodiment, an excited plasma of tin (Sn) is provided to generate EUV radiation.

[0091] The radiation emitted by the hot plasma HP is transferred from the source chamber SC to the collector chamber CC via an optional gas barrier or contaminant trap CT (also referred to as a contaminant barrier or foil trap in some cases) positioned in or behind an opening in the source chamber SC. The contaminant trap CT may include a channel structure. The contaminant trap CT may also include a gas barrier, or a combination of a gas barrier and a channel structure. As is known in the art, the contaminant trap or contaminant barrier CT further indicated herein includes at least a channel structure.

[0092] The collector chamber CC may include a radiation collector CO, which may be a so-called grazing incidence collector. The radiation collector CO has an upstream radiation collector side US and a downstream radiation collector side DS. Radiation passing through the radiation collector CO may be reflected by a grating spectral filter SF to be focused in a virtual source point IF along an optical axis indicated by a dash-dot line 'O'. The virtual source point IF may be referred to as an intermediate focus, and the source collector module may be arranged such that the intermediate focus IF is located at or near an opening OP in the enclosed structure ES. The virtual source point IF is an image of the radiation emitting plasma HP.

[0093] The radiation then passes through an illumination system IL which may include a faceted field mirror arrangement FM and a faceted pupil mirror arrangement pm arranged to provide a desired angular distribution of the radiation beam B at the patterning device MA and a desired uniformity of the amplitude of the radiation at the patterning device MA. Upon reflection of the radiation beam B at the patterning device MA held by the support structure MT, a patterned beam PB is formed and is imaged by the projection system PS via a reflective element RE onto a substrate W held by a substrate table WT.

[0094] More elements than those illustrated may typically be present in the illumination optics unit IL and the projection system PS. Depending on the type of lithographic apparatus, a grating spectral filter SF may optionally be present. Further, there may be more mirrors than shown in the drawings, for example there may be 1 to 6 additional reflective elements in the projection system PS.

[0095] The collector optics CO may be a nested collector with a grazing incidence reflector GR, like the example of a collector (or collector mirror). The grazing incidence reflector GR is arranged axisymmetrically around the optical axis O, and this type of collector optics CO may be used in combination with a discharge produced plasma source, generally referred to as a DPP source.

[0096] Fig.13 is a detailed view of a source collector module SO of a lithographic projection apparatus LPA according to an embodiment of the present disclosure.

[0097] The source collector module SO may be part of an LPA radiation system. The laser LA may be arranged to deposit laser energy into a fuel, such as xenon (Xe), tin (Sn) or lithium (Li), thereby producing a highly ionized plasma HP with an electron temperature of several tens of eV. The energetic radiation generated during the deexcitation and recombination of these ions is emitted from the plasma, collected by a collector optical device CO at near normal incidence and focused onto an opening OP in the enclosed structure ES.

[0098] The embodiments may also be described using the following terms:

[0099] 1. A system comprising:

[0100] a reflector assembly, comprising a first reflector and a second reflector; and

[0101] a movable stage to which the mirror group is mounted so that the first mirror and the second mirror move together with the movable stage,

[0102] wherein the first reflector is configured to receive the beam at a first angle to the axis of the reflector assembly,

[0103] wherein the second reflector is configured to provide said beam at a second angle to the axis of the reflector assembly, the beam providing the output after reflection by the second reflector,

[0104] wherein movement of the mirror assembly parallel to the axis causes a parallel displacement of the output along the beam, and

[0105] Wherein movement of the mirror assembly perpendicular to the axis causes a vertical displacement of the output perpendicular to the beam.

[0106] 2. A system according to clause 1, wherein the beam is a light beam from a light source in an optical scanning device.

[0107] 3. A system according to clause 2, wherein the output is a focus of the light beam.

[0108] 4. A system according to clause 1, further comprising an objective lens for receiving the output and configured to move with the movable stage, wherein during movement of the movable stage and the objective lens, the output remains stationary relative to the objective lens.

[0109] 5. A system according to clause 1, wherein the angle ratio being the ratio between the first angle and the second angle determines a movement ratio of the movable stage, the movement ratio being the ratio of the amount of movement at the output to the amount of movement at the movable stage.

[0110] 6. A system according to clause 5, wherein the angle between the input and the output is 120 degrees, such that the ratio is 1.

[0111] 7. A system according to clause 1, further comprising:

[0112] an objective lens for receiving the output, the objective lens being configured to move in a first direction together with the movable stage; and

[0113] a first static mirror, the first static mirror being configured to direct the beam to the objective lens,

[0114] Wherein moving the movable stage and the objective lens along the first direction maintains the position of the output at the objective lens along the second direction.

[0115] 8. A system according to clause 7, wherein the objective lens is mechanically coupled to the movable stage.

[0116] 9. A system according to clause 7, wherein the objective lens is electronically controlled to move in correspondence with movement of the movable stage.

[0117] 10. A system according to clause 7, wherein movement of the movable stage in the second direction causes corresponding movement of the output relative to the objective lens.

[0118] 11. A system according to clause 1, further comprising:

[0119] an objective lens for receiving the output, the objective lens being configured to move in the first direction and / or the second direction together with the movable stage; and

[0120] a first static mirror configured to redirect the beam toward the objective lens;

[0121] a second static mirror, the second static mirror being configured to direct the beam to the first static mirror,

[0122] Wherein the movable stage and the objective lens are moved to maintain a displacement along the first direction and along the second direction to maintain a position of the output at the objective lens.

[0123] 12. A system according to clause 7, further comprising:

[0124] a second static reflector configured to direct the beam to the reflector set;

[0125] a second mirror group, the second mirror group being oriented perpendicular to and beyond the plane of the mirror group, and the second mirror group being configured to direct the beam from the second mirror group to the mirror group;

[0126] a second movable stage to which the second reflective mirror set is mounted;

[0127] a third static mirror, the third static mirror being configured to direct the beam from the second mirror group to the second static mirror,

[0128] Wherein moving the second reflector set in a first direction allows adjustment of the output in the first direction, moving the second reflector set in a second direction allows adjustment of the output in the second direction, and moving the second reflector set in a third direction does not change the positioning of the output in the third direction.

[0129] 13. A system according to clause 12, wherein the system is configured to move the second mirror group and the objective lens relative to the mirror group in the second direction, thereby moving the output along the second direction.

[0130] 14. A system according to clause 12, wherein the objective lens is further configured to move in the second direction independently of the mirror group, wherein maintaining a displacement between the second mirror group and the objective lens in the second direction maintains the position of the output relative to the objective lens in the second direction.

[0131] 15. A system according to clause 1, further comprising:

[0132] an objective lens for receiving the output, the objective lens being configured to move together with the movable stage to maintain the same displacement between the objective lens and the movable stage in both the first direction and the third direction;

[0133] a first static mirror configured to direct the beam to an objective lens;

[0134] a second static mirror configured to direct the beam to the first static mirror; and

[0135] a folding mirror coupled to the movable stage and configured to rotate the beam along a second direction;

[0136] The movable stage and the objective lens are moved to maintain the displacement to keep the position of the output at the objective lens along the second direction.

[0137] The concepts disclosed herein can simulate or mathematically model any general imaging system for imaging sub-wavelength features and may be particularly useful for emerging imaging technologies that can produce shorter and shorter wavelengths. Emerging technologies already in use include EUV (extreme ultraviolet), DUV lithography, which can produce wavelengths of 193 nm using ArF lasers, and even 157 nm using fluorine lasers. Moreover, EUV lithography can produce wavelengths in the range of 20 nm to 50 nm by using synchrotrons or by bombarding materials (solid or plasma) with high-energy electrons to produce photons in this range.

[0138] Although the concepts disclosed herein may be used for imaging on substrates such as silicon wafers, it should be understood that the disclosed concepts may be used with any type of lithography imaging system, such as those used for imaging on substrates other than silicon wafers.

[0139] The combinations and sub-combinations of the elements disclosed herein constitute separate embodiments and are provided as examples only. Moreover, the above description is intended to be illustrative, not restrictive. Therefore, it will be apparent to those skilled in the art that modifications may be made as described without departing from the scope of the claims set forth below.

Claims

1. A system comprising: A reflector group, the reflector group comprising a first reflector and a second reflector; as well as a movable stage to which the reflector group is mounted so that the first reflector and the second reflector can move together with the movable stage, wherein the first reflector is configured to receive a beam at a first angle to an axis of the reflector assembly, wherein the second reflector is configured to provide the beam at a second angle to the axis of the reflector assembly, the beam providing an output after being reflected by the second reflector, wherein movement of the mirror set parallel to the axis causes a parallel displacement of the output along the beam, and Wherein, movement of the mirror assembly perpendicular to the axis causes a vertical displacement of the output perpendicular to the beam.

2. The system according to claim 1, wherein: The beam is a light beam from a light source in an optical scanning device.

3. The system according to claim 2, wherein: The output is the focus of the light beam.

4. The system of claim 1 , further comprising an objective lens for receiving the output and configured to move with the movable stage, wherein during movement of the movable stage and the objective lens, the output remains stationary relative to the objective lens.

5. The system according to claim 1, wherein: The angle ratio, which is a ratio between the first angle and the second angle, determines a movement ratio of the movable stage, the movement ratio being a ratio of a movement amount at the output to a movement amount at the movable stage.

6. The system according to claim 5, wherein: The angle between the input and the output is 120 degrees, making the ratio 1.

7. The system of claim 1, further comprising: an objective lens for receiving the output, the objective lens being configured to move in a first direction together with the movable stage; as well as a first static mirror configured to direct the beam to the objective lens, wherein moving the movable stage and the objective lens along the first direction maintains a position of the output at the objective lens along a second direction.

8. The system according to claim 7, wherein: The objective lens is mechanically coupled to the movable stage.

9. The system according to claim 7, wherein: The objective lens is electronically controlled to move corresponding to the movement of the movable stage.

10. The system according to claim 7, wherein: Movement of the movable stage in the second direction causes corresponding movement of the output relative to the objective lens.

11. The system of claim 1 , further comprising: an objective lens for receiving the output, the objective lens being configured to move in a first direction and / or a second direction together with the movable stage; a first static mirror configured to redirect the beam toward the objective lens; a second static mirror configured to direct the beam to the first static mirror, wherein moving the movable stage and the objective lens to maintain displacement along the first direction and along the second direction maintains the position of the output at the objective lens.

12. The system according to claim 7, further comprising: a second static mirror configured to direct the beam to the mirror set; a second reflector group oriented perpendicular to and beyond the plane of the reflector group and configured to direct the beam from the second reflector group to the reflector group; a second movable stage, the second reflective mirror set being mounted to the second movable stage; a third static mirror configured to direct the beam from the second mirror group to the second static mirror, Wherein moving the second reflector group in the first direction allows the output to be adjusted in the first direction, moving the second reflector group in the second direction allows the output to be adjusted in the second direction, and moving the second reflector group in a third direction does not change the positioning of the output in the third direction.

13. The system according to claim 12, wherein: The system is configured to move the second mirror group and the objective lens in the second direction relative to the mirror group, thereby moving the output along the second direction.

14. The system according to claim 12, wherein: The objective lens is also configured to move in the second direction independently of the mirror group, wherein maintaining a displacement between the second mirror group and the objective lens in the second direction maintains the position of the output relative to the objective lens in the second direction.

15. The system of claim 1, further comprising: an objective lens for receiving the output, the objective lens being configured to move together with the movable stage to maintain the same displacement between the objective lens and the movable stage in both the first direction and the third direction; a first static mirror configured to direct the beam to the objective lens; a second static reflector configured to direct the beam to the first static reflector; as well as a folding mirror coupled to the movable stage and configured to rotate the beam along a second direction; wherein the movable stage and the objective lens are moved to maintain the displacement to keep the position of the output at the objective lens along the second direction.

Images