Two-axis movement with linear actuators

Abstract

Various examples include an apparatus that provides motion in at least two linear axes, each of the linear axes being substantially orthogonal to one another. The apparatus can include a load stage having a first actuator (e.g., a modified linear motor) coupled to the load stage to provide linear motion to the load stage in a first direction. A wide magnet pack is coupled to the first actuator or included as part of the first actuator. The wide magnet pack has a width sufficient to allow movement of the load stage in a second direction without impairing operation of the linear motor, the second direction being substantially orthogonal to the first direction. A second actuator is also coupled to the load stage to provide linear motion in the second direction, substantially within the magnetic field constraints of the wide magnet pack. Other systems, apparatus, and devices are also disclosed.

Description

[Technical Field]

[0001] (Priority Claim) This application claims the benefit of priority to U.S. Provisional Patent Application No. 63 / 385,356, entitled "TWO-AXIS-MOTION FROM A LINEAR ACTUATOR," filed November 29, 2022, and U.S. Provisional Patent Application No. 63 / 545,815, entitled "BELL-CRANK ASSEMBLY TO PROVIDE DIRECTIONAL MOTION," filed October 26, 2023, each of which is incorporated by reference in its entirety.

[0002] FIELD OF THE INVENTION The disclosed subject matter generally relates to the field of movement of equipment and devices in various physical directions, such as lithography, substrate inspection, and metrology tools used in three-dimensional printing and other applications, as well as semiconductor and related industries (e.g., flat panel display and solar cell production facilities). More specifically, in various embodiments, the disclosed subject matter relates to two-axis linear actuators used to transport various types of inspection and metrology tools in two or more directions, including x, y, z, and theta directions, relative to a substrate mounted below the linear actuator. In other embodiments, the disclosed subject matter relates to linear motion systems that control the height of a load stage in the z direction (e.g., above a substrate mounted below the load stage) without substantially tilting or other theta rotation of the load stage. [Background technology]

[0003] Current linear motion systems typically provide positioning in two or more directions using independent motion and bearing systems. These linear motion systems often include a linear motion x-axis table and a separate linear motion y-axis table attached to the x-axis table to provide x-y positioning capability. Additionally, a theta rotation stage is often attached to the x-axis and y-axis table combination, providing movement of a load (e.g., substrate, metrology tool component, optical system, etc.) in the x-direction, z-direction, and the theta rotational direction.

[0004] Additionally, current types of linear motion systems often face problems with keeping the load stage (e.g., to which various types of optical metrology and other devices may be attached) moving in a straight line and in-line at speeds encountered in high-speed operations such as metrology, overlay, characterization, and / or inspection equipment.

[0005] What is needed is a lightweight device that does not use a separate linear motion x-axis table and a separate linear motion y-axis table to provide load positioning. Various embodiments of the disclosed subject matter can provide at least two axes (e.g., linear or rotational) of motion within an actuator (e.g., a single linear actuator). The same single linear actuator can also provide theta rotational motion.

[0006] Additionally, various embodiments disclose apparatus that provide motion to a load stage configured to hold optical components, such as those used in various types of equipment, such as metrology, overlay, characterization, and / or inspection equipment, as the load stage passes over a substrate (e.g., semiconductor substrate, flat panel display, panel, wafer, etc.). Consequently, in various embodiments, the disclosed subject matter is configured to move the load stage in the z-direction (e.g., in a first direction relative to the substrate) without substantially tilting or other theta rotation from a selected z-height, while allowing other linear actuators to move the load stage in the x- and y-directions (e.g., in a second and third direction, respectively). Summary of the Invention

[0007] This document describes, among other things, an apparatus providing motion in at least two axes, each of the linear axes being substantially orthogonal to one another. In various embodiments, the apparatus can also include a theta rotation stage. The apparatus can include a load stage having a first actuator (e.g., a modified linear motor) coupled to the load stage to provide linear motion to the load stage in a first direction. A wide magnet pack is coupled to the first actuator or included as part of the first actuator. The wide magnet pack has a width sufficient to allow movement of the load stage in a second direction substantially orthogonal to the first direction. A second actuator is also coupled to the load stage to provide linear motion in the second direction, substantially within the constraints of the wide magnet pack. As described in more detail herein, the second actuator is arranged to provide at least one of linear motion and rotational motion in the second direction to the load stage by moving the load stage in the second direction, for example, using one or more linear actuators or one or more voice coil motors.

[0008] Additionally, various embodiments disclosed herein can provide motion to a load stage configured to hold optical components, such as those used in various types of equipment, such as metrology, overlay, characterization, and / or inspection equipment, as the load stage passes over a substrate (e.g., a semiconductor substrate, a flat panel display, a panel, a wafer, etc.).

[0009] In various embodiments, the disclosed subject matter is an apparatus for providing motion in at least two linear axes, each of the at least two linear axes being substantially orthogonal to one another. The apparatus includes a load stage. A first actuator is coupled to the load stage to provide linear motion to the load stage in a first direction. A wide magnet pack is coupled within the first actuator. The wide magnet pack has a width sufficient to allow movement of the load stage in a direction substantially orthogonal to the first direction. At least one second actuator is also coupled to the load stage to provide at least one of linear and rotational motion to the load stage in a second direction substantially orthogonal to the first direction.

[0010] In various embodiments, the disclosed subject matter is an apparatus for providing motion in at least two linear axes, each of the at least two linear axes being substantially orthogonal to one another. The apparatus includes a load stage having a mounting plate and a first linear motor configured to provide linear motion to the load stage in a first direction. The first linear motor includes a magnet pack and a coil bearing plate. The coil bearing plate is coupled to the mounting plate of the load stage and is substantially surrounded on at least two sides by the magnet pack. The coil bearing plate is positioned to move the load stage in at least the first direction via a magnetic field generated within the first linear motor. The present application further includes at least one second actuator coupled to the load stage. The at least one second actuator provides linear motion to the load stage in at least a second direction substantially orthogonal to the first direction.

[0011] In various embodiments, the disclosed subject matter is an apparatus for providing motion in at least two linear axes, each of the at least two linear axes being substantially orthogonal to one another. The apparatus includes a first linear motor for providing linear motion in a first direction. The first linear motor includes a magnet pack and a coil bearing plate. The coil bearing plate is substantially surrounded on at least two sides by the magnet pack. The coil bearing plate is positioned to move in at least the first direction via a magnetic field generated within the first linear motor.

[0012] In various embodiments, the disclosed subject matter is configured to move the load stage in the z direction (e.g., a first direction relative to the substrate) without substantially tilting or other theta rotation from a selected z height, while allowing other linear actuators to move the load stage in the x and y directions (e.g., a second and third direction, respectively).

[0013] In various embodiments, the disclosed subject matter is an apparatus for providing motion to a load stage in a first direction while simultaneously enabling motion of the load stage in a second and third direction. The apparatus includes a shaft that applies torque to the load stage and one or more z-direction load-stage actuators mechanically coupled to the shaft to adjust the height of the load stage above the workpiece. A motion actuator is mechanically coupled to the shaft and positioned proximate to the one or more z-direction load-stage actuators for applying a force to the shaft.

[0014] In various embodiments, the disclosed subject matter is an apparatus for providing motion to a load stage in a first direction while simultaneously enabling motion of the load stage in a second and third directions, each of which is substantially orthogonal to one another. The apparatus includes a shaft for applying torque to the load stage, at least one pair of z-direction load-stage actuators mechanically coupled to one another and attached to opposite ends of the shaft, the at least one pair of z-direction load-stage actuators adjusting the height of the load stage above the substrate, and a motion actuator located between the at least one pair of z-direction load-stage actuators. The motion actuators are configured to apply a force to the shaft in a direction substantially transverse to the direction of a force applied to the load stage by the at least one pair of z-direction load-stage actuators. A bell crank assembly is coupled between the motion actuators and the shaft. The bell crank assembly is configured to supply a force to the shaft to apply torque to the at least one pair of z-direction load-stage actuators.

[0015] The various accompanying drawings merely illustrate example implementations of the present disclosure and are not to be considered as limiting its scope. [Brief explanation of the drawings]

[0016] [Figure 1] 1 illustrates an example of an apparatus configured to move instruments and devices in various physical directions that incorporates various embodiments of the disclosed subject matter. [Figure 2A] 2 shows a perspective view of another example of a multi-axis motion system incorporating air bearings and a modified version of a linear motor that may be used with the substrate inspection system of FIG. 1. [Figure 2B] 2B shows a side view of the example multi-axis motion system of FIG. 2A. [Figure 3] 2A and 2B, to which a load, such as an optical assembly of a substrate inspection or metrology system, may be attached. [Figure 4A]4 illustrates a rear perspective view of the multi-axis motion system of FIG. 3 in accordance with various embodiments. [Figure 4B] 4 illustrates a front perspective view of the multi-axis motion system of FIG. 3 in accordance with various embodiments. [Figure 5A] FIG. 1 illustrates an example of a rear perspective view of an exemplary load stage incorporating various embodiments of the disclosed subject matter. [Figure 5B] 5B illustrates a top perspective view of the load stage of FIG. 5A incorporating various embodiments of the disclosed subject matter. [Figure 5C] FIG. 5B illustrates a front perspective view of a portion of the load stage of FIG. 5A incorporating various embodiments of the disclosed subject matter. [Figure 5D] 5B shows a top perspective view of a portion of the load stage of FIG. 5A housing a motion actuator, according to various embodiments of the disclosed subject matter. [Figure 5E] 5D shows a top perspective view of a portion of the load stage of FIG. 5A, showing the motion actuator and z-direction load stage actuator mounted transversely to the z-direction load stage actuator linear actuator of FIG. 5D. [Figure 6] 1 illustrates an example block diagram comprising a machine upon which any one or more of the techniques (eg, methodologies) discussed herein may be implemented. DETAILED DESCRIPTION OF THE INVENTION

[0017] Various embodiments of the disclosed subject matter are directed to an apparatus providing motion in at least two linear axes, each of the linear axes being substantially orthogonal to one another. The apparatus can include a load stage having a first actuator (e.g., a modified linear motor) coupled to the load stage to provide linear motion to the load stage in a first direction. A wide magnet pack is coupled to the first actuator or included as part of the first actuator. The wide magnet pack has a width sufficient to allow movement of the load stage in a second direction substantially orthogonal to the first direction. A second actuator is also coupled to the load stage to provide linear motion in the second direction, substantially within the constraints of the wide magnet pack. As described in more detail herein, the second actuator is arranged to provide at least one of linear and rotational motion in the second direction to the load stage by moving the load stage in the second direction, for example, using one or more linear actuators or one or more voice coil motors.

[0018] Various embodiments of the disclosed subject matter include bell crank assemblies as disclosed herein that adjust the orthogonality and alignment of mechanisms that provide two-axis motion. Consequently, various examples herein describe apparatus that provide motion to a load stage configured to hold optical components, such as those used in various types of equipment, such as overlay, characterization, and / or inspection equipment, as the load stage passes over a substrate (e.g., a semiconductor substrate, a flat panel display, a panel, a wafer, etc.). In various embodiments, the disclosed subject matter is configured to move the load stage in the z-direction relative to the substrate without substantial tilt or other theta rotation from a selected z-height, while allowing other linear actuators to move the load stage in the x- and y-directions.

[0019] Thus, the disclosed subject matter in various embodiments provides precision motion in at least two axes. Rotational motion may also be imparted to the load stage by using another linear actuator mounted near the load stage, off-center, or on one edge of the load stage, thereby imparting tilt or twist motion (providing theta rotation).

[0020] Current two-axis linear motion systems typically provide positioning in two or more directions using independent motion and bearing systems. These linear motion systems often include a linear motion x-axis table and a separate linear motion y-axis table attached to the x-axis table to provide x-y positioning capabilities. Typically, each current linear motion system uses a separate linear electric motor in each orthogonal direction to generate linear force along the length of the linear motor. Additionally, a theta rotation stage is often attached to the x-axis and y-axis table combination to provide movement of a load (e.g., substrate, metrology tool component, optical system, etc.) in the x-, y-, and theta rotational directions. Each of these separate translation stages can add significant weight and physical size to current linear motion systems.

[0021] In various embodiments, encoding the direction of linear motion (e.g., scanning motion) may use a laser interferometer to determine the distance traveled by the load stage. Multiple laser interferometers may be used to encode linear motion in two or more directions and theta rotation. However, other non-contact and contact techniques can also be used to determine encoded position. For example, non-contact sensors can detect or measure physical properties, such as the distance of an object, without directly contacting the object. Examples of non-contact sensors include fiber optic sensors (which use an optical fiber with a pair of photodetectors located at each end of the fiber and a light source attached to the object) and capacitive probe sensors (which rely on detecting changes in capacitance to establish the position of the measured object). Contact sensors include, for example, potentiometric position sensors (which use a resistive track and wiper to measure resistance changes due to object movement) and inductive position sensors (which use a contact probe located within a coil whose magnetic field changes depending on the position of the probe connected to the object).

[0022] The orientation of the load is controlled using a set of bearings, which can be adjusted using one or more actuators. Adjustment of the one or more actuators can change the orientation of the load rotationally and laterally, as described in detail below. As discussed above, the position of these actuators can be monitored using various types of position encoding systems and techniques.

[0023] Overall, the design of the disclosed subject matter creates planar motion of the load, eliminating the need for stacked stages (e.g., an x-axis stage mounted on a y-axis stage (or z-axis stage) for two-dimensional motion, or a theta rotation stage mounted on a one- or two-dimensional linear axis stage). Additionally, using a two-axis motion design as disclosed herein reduces the moving mass of the combined axes, thereby improving dynamic performance and throughput. The use of a single air bearing system to define the motion plane in scan and theta can also improve stability and predictability while also improving autofocus operation, thereby improving the focus position of the load in metrology applications, for example.

[0024] For example, referring now to FIG. 1 , an example of a substrate inspection or metrology system 100 incorporating various embodiments of the disclosed subject matter is shown. FIG. 1 is shown to include a transfer bridge 101, a substrate stage platform 103, system legs 105, a substrate stage 107, and a y-direction substrate stage transport mechanism 109. FIG. 1 is also shown to include an example of a substrate inspection or metrology load, such as an optical assembly 111, having an exemplary objective lens turret 115. The optical assembly 111 is attached to an exemplary version of a modified linear motor 113. However, the optical assembly 111 is provided merely as an example of a device or one piece of equipment that can benefit from the disclosed subject matter. As mentioned above, the disclosed subject matter generally relates to the field of movement of equipment and devices in various physical directions, such as lithography, substrate inspection, and metrology tools used in three-dimensional printing and other applications, as well as semiconductor and related industries (e.g., flat panel display, battery, and solar cell production facilities).

[0025] The transfer bridge 101 is positioned such that the optical assembly 111 may be traversed in the ±x direction over the substrate stage 107 by a modified linear motor 113. The modified linear motor 113 further enables the optical assembly 111 to move in the ±z direction, as described in more detail below. However, as described herein, movement in the ±z direction does not require a separate second motor (e.g., a linear motor) mounted orthogonally to a first motor (e.g., another linear motor moving in the ±x direction), as is found in the prior art. Upon reading and understanding the disclosed subject matter, those skilled in the art will recognize that the modified linear motor 113 may be oriented in a variety of positions. Thus, the modified linear motor 113 may be positioned to move any load, for example, in the ±x and ±y directions. Alternatively, the modified linear motor 113 can be positioned to provide movement in the ±y and ±z directions. As described in more detail below with reference to FIGS. 4A and 4B, a load stage actuator can be used to impart an optional theta rotation to the optical assembly 111 or other load stage.

[0026] The substrate stage 107 allows a substrate attached to it to move in ±y directions beneath the transfer bridge 101. A y-direction substrate stage transport mechanism 109 can move the substrate stage 107 in ±y directions that are substantially perpendicular to the direction in which the transfer bridge 101 is disposed. The y-direction substrate stage transport mechanism 109 is attached to the substrate stage platform 103. In various embodiments, the substrate stage platform 103 may include a granite block that rests on or is supported by the system legs 105. In other embodiments, the substrate stage transport mechanism 109 can move the substrate stage 107 in a direction that is non-orthogonal to the direction in which the transfer bridge 101 is disposed.

[0027] The optical assembly 111 is mechanically coupled to a load stage (not shown, but described below beginning with FIG. 2A ), which is mechanically coupled to a modified linear motor 113. Although the optical assembly 111 is shown in conjunction with a substrate inspection device (e.g., a substrate scanner) or a metrology device (e.g., an optical profilometer), this configuration is provided only as an example to describe various ways in which the modified linear motor 113 may be used.

[0028] As described in more detail below, the modified linear motor 113 allows for attachment of various types of devices. As shown in the exemplary embodiment of Figure 1, the modified linear motor 113 is configured to move the optical assembly 111 in both the x and z directions.

[0029] As partially described above, current two-axis linear motion systems typically provide positioning in two or more directions using independent motion and bearing systems. These linear motion systems often include a linear motion x-axis table and a separate linear motion y-axis table attached to the x-axis table to provide x-y positioning capabilities. Other types of two-axis linear motion systems, such as two-axis linear stepper motors (e.g., Sawyer motors), are linear motors with a plate that can move in the x and y directions, but require magnets laid out in two directions on the platen, or a grid pattern laid out in a ferrous material. Using the system described herein, there is no need to lay out magnets in two directions.

[0030] In contrast to prior art systems, the disclosed subject matter has a first actuator (e.g., a modified linear motor) coupled to the optical assembly 111 to provide linear motion in a first direction (e.g., ±x direction) to a load stage (on which the optical assembly 111 is mounted). A wide magnet pack is coupled to the first actuator or included as part of the first actuator. The wide magnet pack has a width sufficient to allow movement of the load stage in a second direction (e.g., ±x direction) substantially orthogonal to the first direction. As a result, the width of the magnet pack proximate to the coil of the actuator remains within the effective magnetic field even when the coil is moved in the orthogonal direction. As described below, a second actuator is also coupled to the load stage to provide linear motion in the second direction, substantially within the confines of the useful magnetic field region of the wide magnet pack. The term “useful” may be considered to be within the turns of the coil, such that the same or substantially the same magnetic field pattern is experienced by the coil regardless of its position within the wide magnet pack.

[0031] Figure 2A shows a perspective view of another example of a multi-axis motion system 200 incorporating air bearings and a modified version of a linear motor that may be used with the substrate inspection system of Figure 1. Figure 2A is shown to include a transfer bridge 201, a substrate stage platform 203, system legs 205, a substrate stage 207, a y-direction substrate stage transport mechanism 209, and a modified linear motor 213A. Each of the components including the transfer bridge 201, the substrate stage platform 203, the system legs 205, the substrate stage 207, the y-direction substrate stage transport mechanism 209, and the modified linear motor 213A may be the same as or similar to the similar components identified in Figure 1. Figure 2A is also shown to include a bearing 215 (e.g., an air bearing or a vacuum air bearing) and a position encoder 219.

[0032] Figure 2A is also shown to include a load stage 211, to which various types of substrate inspection and metrology devices, such as the optical assembly 111 of Figure 1, may be attached. The load stage 211 is mechanically coupled to a modified linear motor 213A. Also shown in Figure 2A are z-direction load stage actuators 217A, 217B, which can be used to apply vertical (e.g., ±z) forces to the load stage 211, as described in more detail below. The load stage actuators 217A, 217B can also be used to impart an optional theta rotation to the load stage 211, as described below with reference to Figures 4A and 4B.

[0033] The z-direction load stage actuators 217A, 217B are arranged to move the load stage 211 (and any devices attached to it) in the ±z direction in this example. The load stage actuators 217A, 217B may be used, for example, to allow movement of an optical assembly attached to the load stage perpendicular to the substrate stage 207 (e.g., in the z direction) to allow the optical assembly to be focused over a range.

[0034] The load-stage actuators 217A, 217B may comprise various types of linear displacement transducers, such as linear variable-displacement transducers (LVDTs), or various types of pneumatically, hydraulically, magnetically, and electrically actuated slides (e.g., spring-loaded or double-acting), voice coil actuators, vise-coil motors, etc. When actuated, the load-stage actuators 217A, 217B move the load stage 211 generally in the ±z direction. Because the wide magnet pack is coupled to or included as part of the first actuator, no second linear motor is required to enable z-direction movement of the modified linear motor 213A. The load stage 211 is coupled to a plate (described in more detail below with reference to FIG. 3) with a coil pack mounted within the actuator and moves within the track of the modified linear motor 213A. The wide magnet pack within the modified linear motor 213A allows the coupled load stage 211 to move along the modified linear motor 213A while still allowing movement in the z direction within the modified linear motor 213A.

[0035] The substrate stage 207, on which the substrate may be mounted or otherwise supported, is supported by bearings 215, which allow for mechanical stabilization of the substrate stage 207. In various embodiments, the bearings 215 may include low-friction supports, such as air bearings or vacuum air bearings, as described above. Air bearings are fluid bearings that use a thin film of pressurized gas to provide a low-friction interface between surfaces. The load stage 211 is also supported by several preload bearings, which are not shown in FIG. 2A but are discussed below with reference to FIGS. 2B and 3.

[0036] The position encoder 219 enables the multi-axis motion system 200 to determine the position of the load stage 211 (e.g., lateral movement of the load stage 211 in the x-direction). In various embodiments, the position encoder 219 may include various types of position sensors, such as, for example, a laser interferometer. Although not explicitly shown, such a position encoder may also be used to determine the position of the load stage 211 in other directions (e.g., the z-direction).

[0037] Figure 2B shows a side view 230 of the example multi-axis motion system 200 of Figure 2A. In addition to the components described above with reference to Figure 2A, Figure 2B is also shown to include support portion 231A, top preload bearing 235, front preload bearing 233, bottom preload bearing 237, and rear preload bearing 239. Only one of each of the preload bearings is shown in Figure 2A, but they are shown in more detail with respect to Figures 4A and 4B, described below.

[0038] Front preload bearing 233 is shown mounted to a front frame portion 243 of load stage 211, and rear preload bearing 239 is shown mounted to a rear frame portion 241 of load stage 211. Bottom preload bearing 237 is shown mounted to a bottom frame portion 245 of load stage 211. In various embodiments, bottom frame portion 245 may not be used.

[0039] Support portion 231 provides additional structural support for transfer bridge 201. Except for a possible preload condition, each of preload bearings 233, 235, 237, 239 is supported by transfer bridge 201 and may be the same as or similar to bearing 215. For example, front preload bearing 233 and top preload bearing 235 maintain a fixed distance relationship between load stage 211 and transfer bridge 201. As shown in more detail with reference to FIG. 3 , each of load stage actuators 217A, 217B is coupled at its lower end to a respective one of top preload bearings 235 to remain in contact with the top portion of transfer bridge 201 regardless of the vertical position (e.g., z-direction) of load stage 211. Each of load stage actuators 217A, 217B is coupled to load stage 211 when load stage actuators 217A, 217B press down on top preload bearing 235.

[0040] The rear preload bearing 239 also maintains a fixed distance relationship between the rear of the load stage 211 and the translation bridge 201. Additionally, the rear preload bearing 239 is arranged as one or more catch bearings that limit the engagement and disengagement of the load stage 211 from the modified linear motor 213A. Thus, the combination of the front preload bearing 233, the top preload bearing 235, and the rear preload bearing 239 all function to mechanically position and stabilize the load stage 211 relative to the translation bridge 201.

[0041] 2B, the bottom preload bearing 237 is shown in contact with the bottom portion of the transfer bridge 201. However, the load stage actuators 217A, 217B can lower and position the load stage 211 closer to the substrate stage 207. In various embodiments, when the load stage 211 is lowered, the bottom preload bearing 237 no longer contacts the transfer bridge 201. In other embodiments, the bottom preload bearing 237 is spring-loaded, for example, and can therefore maintain contact with the transfer bridge 201 regardless of the z-position of the load stage 211.

[0042] FIG. 3 shows a side view 300 of a portion of the multi-axis motion system 200, 230 of FIGS. 2A and 2B to which a load, such as the optical assembly of the substrate inspection or metrology system described above, may be attached. However, as noted above, the disclosed subject matter generally relates to the field of movement of equipment and devices in various physical directions, such as lithography, substrate inspection, and metrology tools used in three-dimensional printing and other applications, as well as semiconductor and related industries (e.g., flat panel display, battery, and solar cell production facilities). In addition to the components described above with reference to FIGS. 2A and 2B, FIG. 3 is shown to include a load stage 211 mechanically coupled to a mounting plate 213C, which is in turn mechanically coupled to a coil bearing plate 213B within a modified linear motor 213A. The coil bearing plate 213B moves within a magnetic field generated within the modified linear motor 213A, thereby actuating motion in the x-direction (see FIG. 2A). The coil bearing plate 213B thereby behaves in a manner similar to the rotor of a rotary motor, and a magnetic field is generated in a manner similar to the stator of a rotary motor. The difference between the modified linear motor 213A and a rotary motor is that the modified linear motor 213A moves in a linear direction rather than a rotational direction. However, because the modified linear motor 213A uses a wider magnet pack (a magnet pack whose width is increased by the expected amount of movement in the z direction), a second linear stage mounted substantially orthogonal to the first linear stage is not required.

[0043] FIG. 4A shows a rear perspective view 400 of the multi-axis motion system 300 of FIG. 3, according to various embodiments. FIG. 4B shows a front perspective view 430 of the multi-axis motion system 300 of FIG. 3, also according to various embodiments. By applying a downward force (negative z-direction) to both load-stage actuators 217A, 217B, the load stage 211 is raised away from the substrate stage 207 (see FIG. 2A). As a result, the load stage 211 is raised in the positive z-direction. Conversely, by applying an upward force (positive z-direction) to both load-stage actuators 217A, 217B, the load stage 211 is lowered toward the substrate stage 207 (the load stage 211 moves in the negative z-direction).

[0044] By applying a downward force (negative z-direction) to a single one of the actuators, for example, load stage actuator 217A, the load stage 211 is tilted in a clockwise direction (as viewed from the front of the load stage 211, as shown in FIG. 2A or 4B), thereby providing the load stage with a theta rotational movement. In a similar manner, by applying a force to load stage actuator 217B, the load stage 211 is tilted in a counterclockwise direction, also as viewed from the front of the load stage 211. In addition to separately applying downward forces to either of the load stage actuators 217A, 217B, an opposing force (one actuator moving upward in the positive z-direction and the other actuator moving downward in the negative z-direction) may achieve an additional amount of theta rotational tilt of the load stage 211.

[0045] In various types of systems, the moving mass of the optical assembly (e.g., focus stage) can be significantly reduced or eliminated by using aspects of the disclosed subject matter. By eliminating a second linear motion system as used by the prior art, dynamic mass can be reduced by approximately 45 kilograms (100 pounds mass) or more. Furthermore, using a single bearing system as described herein to define the plane of motion of an optical system can improve optical alignment, speed, and mechanical stability.

[0046] In various embodiments, the disclosed subject matter is directed to an apparatus for providing z-direction motion to a load stage. In various embodiments, as described in more detail below, the load stage, which can be configured to move across a bridge (e.g., a granite bridge) positioned above the substrate under investigation, is supported above the bridge, e.g., by an air bearing. The load stage can be driven up (+z direction) and down (-z direction) by one or more z-direction load-stage actuators, such as voice coil motors (which act to apply a force to the load stage in the z direction). A motion actuator (e.g., a pneumatically actuated bellows, in some embodiments, acting in a linear direction) acting as part of a bell crank assembly (described below with reference to FIGS. 5C-5E) is coupled between one or more z-direction load-stage actuators and a shaft attached to the motion actuator, the shaft being mechanically coupled to the z-direction load-stage actuators at both ends of the shaft. However, as described in more detail below, only a single z-direction load-stage actuator may be used. As shown in various figures, two z-direction load-stage actuators are shown merely to better illustrate one embodiment of the disclosed subject matter. The shaft is configured to apply torque from a motion actuator, for example, to one or more z-direction load stage actuators, as described below.

[0047] The motion actuator applies a force to the shaft through a bell crank assembly, thereby applying a torque to the shaft. The shaft then applies a torque to one or more z-direction load-stage actuators. The torque applied to the one or more z-direction load-stage actuators serves to maintain or provide a substantially uniform force on the load stage (e.g., synchronized for vertical movement) and substantially prevents any theta rotation of the load stage (relative to the axis about which the load stage is moved in the x-direction, for each side of the load stage, as defined with reference to FIG. 1 ). Thus, the motion actuator applies a force to the shaft in a direction substantially transverse to the direction of the force applied to the load stage by the one or more z-direction load-stage actuators.

[0048] The disclosed subject matter thus limits the amount of rotation in the system, thereby limiting tilt of the load stage. The disclosed bell crank assembly acts as a crank arm that adjusts the relative height of the load stage above the substrate so that the forces from each of the z-direction load stage actuators act in unison on the load stage. The motion actuators carry most of the weight of the load stage, with the z-direction load stage actuators providing the desired height of the load stage above the substrate being inspected (e.g., for focusing optical components mounted on the load stage).

[0049] In an embodiment, an optical encoder may be coupled to at least one end of the shaft and may be used to monitor the z-height of the load stage (e.g., based on the sine (theta) of the shaft rotation). As described above, the motion actuator supplying force to the shaft acts in a direction substantially transverse to the direction of the z-direction load stage actuator acting on the load stage.

[0050] The disclosed subject matter can be used with any type of high-speed system where speed, stability, and linear motion are considerations, such as systems incorporating linear motors mechanically coupled to one another through bell crank assemblies, each motor ensuring perfect coordination between the z-direction load stage actuators to provide high precision z-direction "lift."

[0051] 5A shows a rear perspective view 500 of a load stage 511 incorporating various embodiments of the disclosed subject matter. FIG. 5A shows a first z-direction load-stage actuator 517A, a second z-direction load-stage actuator 517B, a motion actuator 515 located proximate at least one of the z-direction load-stage actuators 517A, 517B, and a pivot point 509 at which each of the z-direction load-stage actuators 517A, 517B may be provided with limited rotational motion substantially about an imaginary line drawn from an approximate center position of the first z-direction load-stage actuator 517A to the second z-direction load-stage actuator 517B. The z-direction load-stage actuators 517A, 517B allow the load stage 511 to be positioned at a height away from the substrate stage 207 (see FIGS. 2A and 2B), for example, to enable focus or other motion that may be mounted on the load stage 511. Although only two z-direction load stage actuators are shown, additional pairs of z-direction load stage actuators may be used. Furthermore, a single z-direction load stage actuator may be used. As shown in the various figures, the two z-direction load stage actuators 517A, 517B are shown merely to better illustrate the disclosed subject matter and one embodiment of the disclosed subject matter.

[0052] As described in more detail below, the motion actuator 515 exerts a force substantially transverse to the force exerted in the ±z direction by the z-direction load stage actuators 517A, 517B on a shaft (not shown in FIG. 5A, but shown and described with reference to FIGS. 5C-5E below).

[0053] 5A is also shown to include z-direction bearing 501 (e.g., air bearings, only one of which is shown in FIG. 5A), encoder 507A and encoder reader 507B, front bearing 503, back bearing 505, and modified linear motor 513 (e.g., x-direction motor). Motion actuator 515 further provides support to the approximate center of load stage 511 and also preloads z-direction bearing 501. Each of the components including load stage 511, z-direction load-stage actuators 517A, 517B, motion actuator 515, and modified linear motor 513 may be the same as or similar to the analogous components described in FIGS. 1, 2A, and 2B.

[0054] The back bearing 505 can be used to maintain a fixed distance relationship between the back of the load stage 511 and the transfer bridge 201 (see FIGS. 2A and 2B). Additionally, the back bearing 505 is arranged as one or more catch bearings that limit the engagement and disengagement of the load stage 511 from the modified linear motor 513. Thus, the combination of the front bearing 503, z-direction bearing 501, and back bearing 505 all function to mechanically position and stabilize the load stage 511 relative to the transfer bridge 201 (see FIGS. 2A and 2B), while still allowing movement in each of the x-, y-, and z-directions.

[0055] The motion actuator 515 comprises one of various types of linear or rotary actuators or other force-applying mechanisms, such as, for example, a pneumatically or hydraulically actuated actuator capable of applying a force to a portion of a bell crank assembly (not shown in FIG. 5A , but shown and described with reference to FIGS. 5C-5E below). The z-direction load-stage actuators 517A, 517B can also comprise, for example, pneumatically or hydraulically actuated actuators capable of applying a force to each of the z-direction bearings 501. In certain exemplary embodiments, the z-direction load-stage actuators 517A, 517B comprise voice coil motors. Each of the voice coil motors, in this example, can receive an electrical signal substantially simultaneously from an electrical signal line (not shown), causing the voice coil motors to operate in unison to raise or lower the load stage 511. If the z-direction load-stage actuators 517A, 517B are, for example, pneumatically or hydraulically actuated, a signal may be sent, for example, to an air reservoir or an oil-filled reservoir, to provide the appropriate fluid to the z-direction load-stage actuators 517A, 517B to operate the actuators substantially in unison to raise or lower the load stage 511. When the z-direction load-stage actuators 517A, 517B are actuated, the z-direction bearings 501 coupled to each of the z-direction load-stage actuators 517A, 517B then exert a force against, for example, a portion of the transfer bridge 201 (see FIGS. 2A and 2B) to raise or lower the load stage 511 in the z direction (see, for example, FIG. 5C).

[0056] By way of example, when an instrument's metrology and / or substrate inspection component (such as, for example, the optical assembly 111 of FIG. 1 ) is attached to the load stage, the load stage 511 may provide movement in the +z direction using a force of approximately 1000 Newtons (approximately 225 pounds-force). In one embodiment, if the z-direction load-stage actuators 517A, 517B comprise voice coil motors, a typical force provided by each voice coil motor may be approximately 250 Newtons (approximately 56 pounds-force) per motor. The interaction between these forces supplied by the z-direction load-stage actuators 517A, 517B and the motion actuators 515 used to stabilize and provide additional and uniform force between the z-direction load-stage actuators 517A, 517B is described in more detail below with reference to FIGS. 5C and 5D . Additionally, various types of force application mechanisms may be used in addition to the disclosed subject matter described herein. Such force application mechanisms include, for example, springs (e.g., extension, compression, torsion), pneumatic cylinders, counterweights, and the like.

[0057] In various embodiments, each of the z-bearing 501, front bearing 503, and rear bearing 505 may include, for example, an air bearing or a vacuum bearing. An air bearing is a fluid bearing that uses a thin film of pressurized gas to provide a low-friction interface between surfaces. The load stage 511 may also be supported by a number of preload bearings, not shown but known in the relevant art.

[0058] The front bearing 503 provides a low-friction interface between the front of the load stage 511 (because the front bearing 503 is attached to the rear portion of the front part of the load stage 511) and, for example, the front portion of the transfer bridge 201 (see FIGS. 2A and 2B), regardless of the vertical position (e.g., in the z direction) of the load stage 511. Similarly, the back bearing 505 provides a low-friction interface between the rear of the load stage (because the rear bearing 505 is attached to the front portion of the rear part of the load stage 511) and, for example, the rear portion of the transfer bridge 201 (see FIGS. 2A and 2B), regardless of the vertical position (e.g., in the z direction) of the load stage 511.

[0059] In various embodiments, encoding of the z-height position is based on the rotation of a shaft (as shown and described below with reference to FIGS. 5C-5E) mechanically coupled between the motion actuator 515 and the z-direction load-stage actuators 517A, 517B. The encoder 507A and encoder reader 507B may be based, for example, on mechanically or optically based encoders that determine the rotation of the shaft. The z-height difference may be calculated, for example, based on the sine of the angular rotation of the shaft. Thus, the difference in height traveled by the load stage 511 may be determined based on a circle-to-line transformation, for example, by applying trigonometric functions. However, other non-contact and contact techniques may also be used to determine the overall z-height of the load stage 511.

[0060] Figure 5B shows a top perspective view 530 of the load stage 511 of Figure 5A incorporating various embodiments of the disclosed subject matter. Figure 5B is shown to include force coupling linkages 519A (located on either side of the motion actuator 515, shown in Figure 5B as exemplary pneumatically actuated bellows) and shaft coupling mechanisms 531 that couple the force generated by the motion actuator 515 to the shaft via the force coupling linkages 519A (each of which is described in more detail below with reference to Figures 5C and 5D). Additionally, Figure 5B shows z-direction bearings 501 mechanically coupled below each of the z-direction load-stage actuators 517A, 517B.

[0061] FIG. 5C shows a front perspective view 550 of a portion of the load stage 511 of FIG. 5A incorporating various embodiments of the disclosed subject matter. FIG. 5C is shown to include a shaft 551, an actuator coupler 553 coupled to the shaft 551 from each of z-direction load stage actuators 517A, 517B, a fixed linear actuator block 519B, and a movable linear actuator block 519C. The force coupling linkage 519A, the fixed linear actuator block 519B, and the movable linear actuator block 519C together form a bell crank assembly. Once actuated, the bell crank assembly provides stabilization to the load stage 511 for a high-precision system. The motion actuator 515 is not shown in FIG. 5C to avoid obscuring the components of the bell crank assembly.

[0062] In operation, when motion actuator 515 applies a force in linear direction 560A from fixed linear actuator block 519B toward movable linear actuator block 519C, the force from motion actuator 515 is transmitted through force coupling linkage 519A and through shaft coupling mechanism 531 to rotate shaft 551 to generate rotational force 560B. Shaft 551 applies a torque to actuator coupler 553 of each of z load-stage actuators 517A, 517B, which applies an additional force that lifts load stage 511 in the +z direction. Z load-stage actuators 517A, 517B are each allowed to rotate slightly about their respective pivot points 509 to reduce or eliminate any coupling that could occur if z load-stage actuators 517A, 517B were fixed and not allowed to rotate slightly.

[0063] The torque applied by shaft 551 also applies substantially the same force to each of z-direction load-stage actuators 517A, 517B, thereby maintaining substantially the same "lift" applied to each side of load stage 511. As a result, in this example, the transfer force applied by motion actuator 515 supplements the lift force supplied through z-direction load-stage actuators 517A, 517B while preventing torsional motion of load stage 511 that could occur if each of z-direction load-stage actuators 517A, 517B did not apply substantially the same force equally.

[0064] When load stage 511 is lowered in the -z direction, the forces described above act in substantially the same manner, with the forces applied in directions opposite those indicated by the linear 560A and rotational 560B arrows. Thus, motion actuator 515 provides additional forces to each of z-direction load-stage actuators 517A, 517B to act in unison after an external up or down signal is provided, as described above. Consequently, in addition to providing additional lift and lateral stabilization of the forces on load stage 511, motion actuator 515 can be considered a type of ballast system.

[0065] An initial calibration of the system may also be applied, adjusting the amount of torque applied to each of the z-direction load stage actuators 517A, 517B by the motion actuator 515. Adjusting the relative position of the shaft coupling mechanism 531 and each of the actuator couplers 553 with respect to their positions on the shaft 551 can provide a calibration that adjusts the amount of torque applied from the shaft 551 to each of the z-direction load stage actuators 517A, 517B in a substantially equal manner.

[0066] In certain exemplary embodiments, shaft 551 may comprise a solid stainless steel rod having a diameter of approximately 35 mm and a length sufficient to span from one of z-direction load-stage actuators 517A, 517B to the other. In embodiments, shaft 551 may comprise other material types predetermined to provide sufficient torque required for a given mass on load stage 511. In embodiments, a larger diameter of shaft 551 may be selected so that the same torque may be applied, but through a hollow (e.g., tubular) shaft 551.

[0067] Continuing with reference to Figures 5B and 5C, Figure 5D shows a top perspective view 570 of a portion of the load stage 511 of Figure 5A housing a motion actuator 515 (not shown in Figure 5D to avoid obscuring the components of the bell crank assembly), in accordance with various embodiments of the disclosed subject matter. As discussed above, the bell crank assembly comprises a force coupling linkage 519A, a fixed linear actuator block 519B, and a movable linear actuator block 519C. Figure 5D provides an additional view of the force applied in a linear direction 560A and the resulting torque in a rotational direction 560B.

[0068] Continuing with reference to Figures 5B-5D, Figure 5E shows a top perspective view 590 of a portion of the load stage 511 of Figure 5A, showing motion actuator 515 (not shown in Figure 5D to avoid obscuring components of the bell crank assembly) and z-direction load-stage actuators 517A, 517B mounted transversely to the motion actuator 515 of Figure 5B. As illustrated by the linear force 560A applied by motion actuator 515 (see Figures 5C and 5D), z-direction load-stage actuators 517A, 517B apply forces in the ±z directions (see Figure 5C). As a result, the linear force 560A is substantially transverse to the forces applied by the z-direction load-stage actuators 517A, 517B.

[0069] The examples described herein may include or operate by logic or several components or mechanisms. Circuitry is a collection of circuits implemented in tangible entities including hardware (e.g., simple circuits, gates, logic, etc.). Circuitry membership may be flexible over time and the variability of the underlying hardware. Circuitry includes elements that, alone or in combination, may, when operating, perform specified operations.

[0070] In one example, for example, the hardware circuitry controlling the z-direction load stage actuators 517A, 517B may be invariably designed (e.g., hardwired) to perform specific operations. In one example, the hardware comprising the circuitry may include variably connected physical components (e.g., execution units, transistors, simple circuits, etc.) including computer-readable media that are physically altered (e.g., magnetically, electrically, etc., via a change in physical state or a transformation of another physical property, etc.) to encode instructions for specific operations.

[0071] When connecting physical components, the underlying electrical properties of the hardware components may be changed, for example, from insulating properties to conductive properties, or vice versa. The instructions enable the embedded hardware (e.g., an execution unit or load mechanism) to create circuit configuration members within the hardware through variable connections to perform portions of specific operations during operation. In one example, any of the physical components may be used in two or more members of two or more circuit configurations. For example, during operation, an execution unit may be used in a first circuit of a first circuit configuration at one time and reused by a second circuit within the first circuit configuration, or by a third circuit within the second circuit configuration at a different time.

[0072] The methods and techniques shown and described herein can be implemented using part or all of a machine 600, as discussed below in connection with Figure 6. Figure 6 shows an example block diagram comprising a machine 600 on which any one or more of the techniques (e.g., methodologies) discussed herein may be performed. In various examples, machine 600 may operate as a standalone device or may be connected (e.g., networked) to other machines.

[0073] In a networked deployment, machine 600 may operate as a server machine, a client machine, or in both capacities in a server-client network environment. In one example, machine 600 may act as a peer machine in a peer-to-peer (P2P) (or other distributed) network environment. Machine 600 may be a personal computer (PC), a tablet device, a set-top box (STB), a personal digital assistant (PDA), a mobile phone, a web appliance, a network router, switch, or bridge, or any machine capable of executing instructions (sequential or otherwise) that specify actions to be taken by that machine. Furthermore, while only a single machine is illustrated, the term “machine” is intended to include any collection of machines individually or collectively executing a set (or sets) of instructions to perform any one or more of the methodologies discussed herein, such as cloud computing, software as a service (SaaS), other computer cluster configurations, etc.

[0074] Examples described herein may include or operate by logic or multiple components or mechanisms. Circuitry is a collection of circuits implemented in tangible entities including hardware (e.g., simple circuits, gates, logic, etc.). Circuitry membership may be flexible over time and the variability of the underlying hardware. Circuitry includes elements that, alone or in combination, may perform specified operations when in operation. In one example, the hardware of a circuitry may be invariably designed (e.g., hardwired) to perform specific operations. In one example, hardware comprising circuitry may include variably connected physical components (e.g., execution units, transistors, simple circuits, etc.) including computer-readable media that are physically altered (e.g., magnetically, electrically, etc., via a change in physical state or a transformation of another physical property) to encode instructions for specific operations. When connecting the physical components, the underlying electrical properties of the hardware components may be altered, for example, from insulating to conductive properties, or vice versa. The instructions enable embedded hardware (e.g., an execution unit or a load mechanism) to create circuitry members within the hardware via variable connections to perform portions of specific operations during operation. Thus, the computer-readable medium is communicatively coupled to other components of the circuitry when the device is operating. In one example, any of the physical components may be used in more than one member of more than one circuitry. For example, during operation, an execution unit may be used in a first circuit of a first circuitry at one time and reused by a second circuit within the first circuitry or by a third circuit within the second circuitry at a different time.

[0075] The machine 600 (e.g., a computer system) may include a hardware-based processor 601 (e.g., a central processing unit (CPU), a graphics processing unit (GPU), a hardware processor core, or any combination thereof), a main memory 603, and a static memory 605, some or all of which may communicate with each other via an interlink 630 (e.g., a bus). The machine 600 may further include a display device 609, an input device 611 (e.g., an alphanumeric keyboard), and a user interface (UI) navigation device 613 (e.g., a mouse). In one example, the display device 609, the input device 611, and the UI navigation device 613 may include at least a portion of a touchscreen display. Machine 600 may additionally include a storage device 620 (e.g., a drive unit), a signal generating device 617 (e.g., a speaker), a network interface device 650, and one or more sensors 615, such as a global positioning system (GPS) sensor, a compass, an accelerometer, or another sensor type. Machine 600 may also include an output controller 619, such as a serial controller or interface (e.g., universal serial bus (USB)), a parallel controller or interface, or other wired or wireless (e.g., infrared (IR) controller or interface, near field communication (NFC)), coupled to communicate with or control one or more peripheral devices (e.g., a printer, a card reader, etc.).

[0076] Storage device 620 may include a machine-readable medium on which is stored one or more sets of data structures or instructions 624 (e.g., software or firmware) that embody or are utilized by any one or more of the techniques or functions described herein. Instructions 624 may also reside, completely or at least partially, within main memory 603, static memory 605, mass storage device 607, or hardware-based processor 601 during execution thereof by machine 600. In one example, one or any combination of hardware-based processor 601, main memory 603, static memory 605, or storage device 620 may constitute a machine-readable medium.

[0077] Although the machine-readable medium is considered a single medium, the term "machine-readable medium" may include a single medium or multiple media (e.g., a centralized or distributed database, and / or associated caches and servers) configured to store one or more instructions 624.

[0078] The term "machine-readable medium" may include any medium capable of storing, encoding, or carrying instructions for execution by machine 600 and causing machine 600 to perform any one or more of the techniques of this disclosure, or capable of storing, encoding, or carrying data structures used by or associated with such instructions. Non-limiting examples of machine-readable media include solid-state memory and optical and magnetic media. Thus, machine-readable media are not transitory, propagating signals. Specific examples of large-scale machine-readable media include semiconductor memory devices (e.g., Electrically Programmable Read-Only Memory (EPROM), Electrically Erasable Programmable Read-Only Memory (EEPROM)) and non-volatile memory such as flash memory devices, magnetic or other phase-change or state-change memory circuits, magnetic disks such as internal hard disks and removable disks, magneto-optical disks, and CD-ROM and DVD-ROM disks.

[0079] The instructions 624 may further be transmitted or received over a communications network 621 using a transmission medium via a network interface device 650 utilizing any one of several transport protocols (e.g., frame relay, internet protocol (IP), transmission control protocol (TCP), user datagram protocol (UDP), hypertext transfer protocol (HTTP), etc.). Exemplary communication networks can include local area networks (LANs), wide area networks (WANs), packet data networks (e.g., the Internet), mobile phone networks (e.g., cellular networks), Plain Old Telephone (POTS) networks, and wireless data networks (e.g., the Institute of Electrical and Electronics Engineers (IEEE) 802.22 family of standards known as Wi-Fi®, the IEEE 802.26 family of standards known as WiMax®), the IEEE 802.25.4 family of standards, peer-to-peer (P2P) networks, among others. In one example, network interface device 650 may include one or more physical jacks (e.g., Ethernet, coaxial, or telephone jacks) or one or more antennas that connect to communication network 621. In one example, the network interface device 650 may include multiple antennas that communicate wirelessly using at least one of single-input multiple-output (SIMO), multiple-input multiple-output (MIMO), or multiple-input single-output (MISO) techniques.The term "transmission medium" is intended to include any intangible medium capable of storing, encoding, or carrying instructions for execution by machine 600, including digital or analog communication signals or other intangible media to facilitate communication of such software.

[0080] Upon reading and understanding the disclosed subject matter, those skilled in the art will recognize that while the disclosed subject matter is described in conjunction with a substrate inspection system or metrology system, no such limitation is intended. The use of the disclosed subject matter with a substrate inspection system or metrology system is provided to more readily illustrate possible uses of the disclosed subject matter. Thus, various aspects of the disclosed subject matter can be readily used in many different industries.

[0081] As used herein, the term "or" may be interpreted in an inclusive or exclusive sense. Additionally, other embodiments will be understood by those of ordinary skill in the art based on reading and understanding the disclosure provided. Furthermore, those of ordinary skill in the art will readily understand that the various combinations of the techniques and examples provided herein may all be applied in various combinations.

[0082] Throughout this specification, multiple instances may implement components, operations, or structures that are described as a single instance. Although individual operations are illustrated and described as separate operations, one or more of the individual operations may be performed simultaneously, and unless otherwise stated, the operations do not necessarily require that they be performed in the order illustrated. Structures and functions presented as separate components in example configurations may be implemented as combined structures or components. Similarly, structures and functions presented as a single component may be implemented as separate components. These and other variations, modifications, additions, and improvements fall within the scope of the subject matter described herein.

[0083] Furthermore, although not explicitly shown, one skilled in the art will understand that each of the various arrangements, quantities, and numbers of elements (e.g., the number of preload bearings or the number of load stage actuators) may be varied. Furthermore, each of the examples shown and described herein is merely representative of one possible configuration and should not be considered as limiting the scope of the present disclosure.

[0084] Although various embodiments are discussed separately, these separate embodiments are not intended to be considered independent technologies or designs. As indicated above, each of the various portions may be interrelated, and each may be used separately or in combination with other embodiments discussed herein. For example, while various embodiments of operations, systems, and processes have been described, these methods, operations, systems, and processes may be used separately or in various combinations.

[0085] Consequently, many modifications and variations are possible, as will be apparent to those skilled in the art upon reading and understanding the disclosure provided herein. In addition to those enumerated herein, functionally equivalent methods and devices within the scope of the present disclosure will be apparent to those skilled in the art from the foregoing description. Portions and features of some embodiments may be included in, or substituted for, portions and features of other embodiments. Such modifications and variations are intended to fall within the scope of the appended claims. Accordingly, the present disclosure is to be limited only by the appended claims, along with the full scope of equivalents to which such claims are entitled. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only, and is not intended to be limiting.

[0086] The Abstract is provided to allow the reader to quickly ascertain the nature of the technical disclosure. The Abstract is submitted with the understanding that it will not be used to interpret or limit the claims. Additionally, in the foregoing Detailed Description, it is recognized that, for the purpose of streamlining the disclosure, various features may be grouped together in a single embodiment. This method of disclosure should not be construed as limiting the claims. Accordingly, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment.

[0087] The description provided herein includes illustrative examples, devices, and apparatuses that embody various aspects of the subject matter described in this document. In the description, for purposes of explanation, numerous specific details are set forth in order to provide an understanding of various embodiments of the subject matter discussed. However, it will be apparent to those skilled in the art that various embodiments of the disclosed subject matter may be practiced without these specific details. Additionally, well-known structures, materials, and techniques have not been shown in detail so as not to obscure the various illustrated embodiments. As used herein, the terms "about," "approximately," and "substantially" may refer to values ​​that are, for example, within +10% of a given value or range of values. The following numbered examples are specific embodiments of the disclosed subject matter.

[0088] Example 1: One embodiment of the disclosed subject matter describes an apparatus for providing motion in at least two linear axes, each of the at least two linear axes being substantially orthogonal to one another. The apparatus includes a load stage. A first actuator is coupled to the load stage to provide linear motion to the load stage in a first direction. A wide magnet pack is coupled within the first actuator. The wide magnet pack has a width sufficient to allow movement of the load stage in a direction substantially orthogonal to the first direction. At least one second actuator is also coupled to the load stage to provide at least one of linear and rotational motion to the load stage in a second direction substantially orthogonal to the first direction.

[0089] Example 2: The apparatus of example 1, wherein the first actuator comprises a linear motor.

[0090] Example 3: The apparatus of any of Examples 1 or 2, wherein the at least one second actuator comprises a voice coil motor.

[0091] Example 4: The apparatus of any of Examples 1 or 2, wherein the at least one second actuator comprises a linear motor.

[0092] Example 5: The apparatus of any one of Examples 1-4, further comprising at least a first set of air bearings coupled to the load stage.

[0093] Example 6: An apparatus described in any one of Examples 1 to 5, further comprising at least one third actuator, the at least one third actuator being coupled proximate to one edge of the load stage and configured to apply a lateral force to the edge to which the third actuator is coupled, the force providing rotational motion to the load stage.

[0094] Example 7: The apparatus of any one of Examples 1 to 6, further comprising at least one back preload bearing attached to a portion of the load stage opposite the portion where the component is attached to the load stage.

[0095] Example 8: The apparatus of any one of Examples 1 to 7, further comprising at least one bottom preload bearing attached to the bottom of the load stage.

[0096] Example 9: The apparatus of example 8, wherein the at least one back preload bearing and the at least one bottom preload bearing each comprise an air bearing.

[0097] Example 10: The apparatus of any one of Examples 1 to 9, further comprising a vacuum air bearing attached to a portion of the load stage opposite the portion where the component is attached to the load stage.

[0098] Example 11: The apparatus of any one of Examples 1 to 10, further comprising at least one position encoding system that indicates the distance of linear movement to the load stage in at least the first direction.

[0099] Example 12: One embodiment of the disclosed subject matter describes an apparatus for providing motion in at least two linear axes, each of the at least two linear axes being substantially orthogonal to one another. The apparatus includes a load stage having a mounting plate and a first linear motor configured to provide linear motion to the load stage in a first direction. The first linear motor includes a magnet pack and a coil bearing plate. The coil bearing plate is coupled to the mounting plate of the load stage and is substantially surrounded on at least two sides by the magnet pack. The coil bearing plate is positioned to move the load stage in at least the first direction via a magnetic field generated within the first linear motor. The apparatus further includes at least one second actuator coupled to the load stage. The at least one second actuator provides linear motion to the load stage in at least a second direction substantially orthogonal to the first direction.

[0100] Example 13: The apparatus of Example 12, wherein the magnet pack has a width sufficient to allow movement of the load stage in a direction substantially perpendicular to the first direction.

[0101] Example 14: The apparatus of either example 12 or example 13, wherein the magnet puck is wide enough to accommodate the expected amount of movement in the second direction.

[0102] Example 15: The apparatus of example 14, wherein the width of the magnet pack is selected such that the coil bearing plate remains substantially within the magnetic field generated by the magnet pack.

[0103] Example 16: An apparatus described in any one of Examples 12 and following, wherein at least one second actuator coupled to the load stage is further configured to provide rotational motion to the load stage.

[0104] Example 17: One embodiment of the disclosed subject matter describes an apparatus providing motion in at least two linear axes, each of the at least two linear axes being substantially perpendicular to one another. The apparatus includes a first linear motor providing linear motion in a first direction. The first linear motor includes a magnet pack and a coil bearing plate. The coil bearing plate is substantially surrounded on at least two sides by the magnet pack. The coil bearing plate is positioned to move in at least the first direction via a magnetic field generated within the first linear motor.

[0105] Example 18: The apparatus of example 17, wherein the linear motion in the second direction does not require a second linear motor attached to the first linear motor.

[0106] Example 19: An apparatus described in any one of Examples 17 and following, wherein the magnet pack has a width sufficient to allow movement of the load stage in a direction substantially perpendicular to the first direction.

[0107] Example 20: An apparatus described in any one of Examples 17 and following, wherein at least one second actuator coupled to the load stage is further configured to provide rotational motion to the load stage.

[0108] Example 21: One embodiment of the disclosed subject matter describes an apparatus that provides motion to a load stage in a first direction while simultaneously enabling motion of the load stage in a second and third direction. The apparatus includes a shaft that applies torque to the load stage and one or more z-direction load-stage actuators mechanically coupled to the shaft to adjust the height of the load stage above the substrate. A motion actuator is mechanically coupled to the shaft and positioned proximate to the one or more z-direction load-stage actuators to apply a force to the shaft.

[0109] Example 22. The apparatus of Example 21, further comprising a bell crank assembly coupled between the motion actuator and the shaft. The bell crank assembly is configured to supply a force to the shaft to apply a torque to the one or more z-direction load stage actuators.

[0110] Example 23: An apparatus as described in Example 22, wherein torque applied to one or more z-direction load stage actuators provides a substantially uniform force on the load stage in the z-direction and substantially prevents any theta rotation of the load stage.

[0111] Example 24: An apparatus described in any one of Examples 1 to 23, wherein the motion actuator is configured to apply a force to the shaft in a direction substantially transverse to the direction of the force applied to the load stage by one or more z-direction load stage actuators.

[0112] Example 25: The device described in any one of Examples 1 to 24, further comprising an encoder that determines a difference in linear distance in the first direction based on a circle-to-straight line transformation.

[0113] Example 26: The device of any one of Examples 1 to 25, wherein the first direction, the second direction, and the third direction are each substantially perpendicular to one another.

[0114] Example 27: An apparatus described in any one of Examples 1 to 26, wherein one or more z-direction load stage actuators are electrically coupled to electrical signal lines to control the height of the load stage above the substrate in the first direction.

[0115] Example 28. An apparatus described in any one of Examples 1 to 27, further comprising a first set of air bearings and a second set of air bearings coupled to the load stage for maintaining a fixed distance relationship between a back surface of the load stage and a transfer bridge on which the load stage is positioned.

[0116] Example 29: An apparatus described in any one of Examples 1 to 28, further comprising at least one back bearing attached to a portion of the load stage opposite the portion where the component is attached to the load stage.

[0117] Example 30: An apparatus described in any one of Examples 1 to 29, further comprising a vacuum air bearing attached to a portion of the load stage opposite the portion where the component is attached to the load stage.

[0118] Example 31: One embodiment of the disclosed subject matter describes an apparatus that provides motion to a load stage in a first direction while simultaneously enabling motion of the load stage in a second direction and a third direction, each of the directions being substantially perpendicular to one another. The apparatus includes a shaft that applies torque to the load stage, at least one pair of z-direction load stage actuators mechanically coupled to one another and attached to opposite ends of the shaft, the at least one pair of z-direction load stage actuators adjusting the height of the load stage above a substrate, and a motion actuator located between the at least one pair of z-direction load stage actuators. The motion actuators are configured to apply a force to the shaft in a direction substantially transverse to the direction of force applied to the load stage by the at least one pair of z-direction load stage actuators. A bell crank assembly is coupled between the motion actuators and the shaft. The bell crank assembly is configured to supply a force to the shaft to apply torque to the at least one pair of z-direction load stage actuators.

[0119] Example 32: An apparatus as described in Example 31, wherein torque applied to at least one pair of z-direction load stage actuators provides a substantially uniform force on the load stage in the z-direction and substantially prevents any theta rotation of the load stage.

[0120] Example 33. An apparatus described in Example 31 or Example 32, wherein the motion actuator applies a force to the shaft in a direction substantially transverse to the direction of the force applied to the load stage by at least one pair of z-direction load stage actuators.

[0121] Example 34: An apparatus described in any one of Examples 31 to 33, wherein at least one pair of z-direction load stage actuators are electrically coupled to electrical signal lines to control the height of the load stage above the substrate in the first direction.

Claims

1. 1. An apparatus for providing motion in at least two linear axes, each of the at least two linear axes being substantially perpendicular to one another, the apparatus comprising: Loading stage and a first actuator coupled to the load stage and configured to provide linear motion to the load stage in a first direction; a wide magnet pack coupled within the first actuator, the wide magnet pack having a width sufficient to allow movement of the load stage in a direction substantially perpendicular to the first direction; and at least one second actuator coupled to the load stage and configured to provide at least one of linear and rotational motion to the load stage in a second direction substantially perpendicular to the first direction.

2. 10. The apparatus of claim 1, further comprising at least one third actuator coupled proximate to an edge of the load stage and configured to apply a transverse force to the edge to which the third actuator is coupled, the force providing rotational motion to the load stage.

3. The apparatus of claim 1 , further comprising at least one back preload bearing mounted on a portion of the load stage opposite the portion where components are mounted on the load stage.

4. The apparatus of claim 1 , further comprising at least one bottom preload bearing mounted to a bottom of the load stage.

5. The apparatus of claim 4 , wherein each of the at least one back preload bearing and the at least one bottom preload bearing comprises an air bearing.

6. The apparatus of claim 1 , further comprising a vacuum air bearing attached to a portion of the load stage opposite the portion where components are attached to the load stage.

7. The apparatus of claim 1 , further comprising at least one position coding system indicating a distance of said linear motion to said load stage in at least said first direction.

8. The apparatus of claim 1 , wherein the first actuator comprises a linear motor.

9. The apparatus of claim 1 , wherein the at least one second actuator comprises a voice coil motor.

10. The apparatus of claim 1 , wherein the at least one second actuator comprises a linear motor.

11. The apparatus of claim 1 , further comprising at least a first set of air bearings coupled to the load stage.

12. 1. An apparatus for providing motion in at least two linear axes, each of the at least two linear axes being substantially perpendicular to one another, the apparatus comprising: a load stage having a mounting plate; a first linear motor configured to provide linear motion to the load stage in a first direction, the first linear motor including a magnet pack and a coil bearing plate, the coil bearing plate coupled to the mounting plate of the load stage and substantially surrounded on at least two sides by the magnet pack, the coil bearing plate positioned to move the load stage in at least the first direction via a magnetic field generated within the first linear motor; and at least one second actuator coupled to the load stage, the at least one second actuator providing at least linear motion to the load stage in a second direction substantially perpendicular to the first direction.

13. 13. The apparatus of claim 12, wherein the magnet pack has a width in a direction substantially perpendicular to the first direction sufficient to allow movement of the load stage in a direction substantially perpendicular to the first direction.

14. 13. The apparatus of claim 12, wherein the magnet pack is wide enough to accommodate an expected amount of movement in the second direction.

15. 15. The apparatus of claim 14, wherein the width of the magnet pack is selected so that the coil bearing plate remains substantially within the magnetic field generated by the magnet pack.

16. The apparatus of claim 12 , wherein the at least one second actuator coupled to the load stage is further configured to provide rotational motion to the load stage.

17. 1. An apparatus for providing motion in at least two linear axes, each of the at least two linear axes being substantially perpendicular to one another, the apparatus comprising:

1. An apparatus comprising: a first linear motor providing linear motion in a first direction, the first linear motor including a magnet pack and a coil bearing plate, the coil bearing plate being substantially surrounded on at least two sides by the magnet pack, the coil bearing plate being arranged to move in at least the first direction via a magnetic field generated within the first linear motor.

18. 18. The apparatus of claim 17, wherein the linear motion in a second direction does not require a second linear motor attached to the first linear motor.

19. 20. The apparatus of claim 17, wherein the magnet pack has a width in a direction substantially perpendicular to the first direction sufficient to allow movement of a load stage in a direction substantially perpendicular to the first direction.

20. 20. The apparatus of claim 17, wherein at least one second actuator coupled to the load stage is further configured to provide rotational motion to the load stage.

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