Platform actuator particle shield

Abstract

A particle shield for an actuator housing in a semiconductor equipment system includes a ring mounted to the actuator housing and a plate mounted to a Z-axis stage that moves relative to the actuator housing. The ring includes a collar that extends from a flange in a Z-coordinate direction. The collar and the plate or a skirt that extends from an outer side perimeter of the plate in the Z-coordinate direction are held in the same plane and do not contact each other during movement of the first Z-axis stage in the Z-coordinate direction. The plate and the collar can be coaxial such that the plate and the collar do not contact each other during rotation of the Z-axis stage relative to the actuator housing. A second Z-axis stage to which a chuck can be mounted passes through a hole in the plate.

Description

[0001] Cross-reference to related applications

[0002] This application claims priority to U.S. Provisional Application No. 63 / 429,912, filed December 2, 2022, entitled “STAGE ACTUATOR PARTICLE SHIELD,” and U.S. Non-Provisional Application No. 18 / 522,038, filed November 28, 2023, both of which are incorporated herein by reference in their entirety. Technical Field

[0003] The subject matter described herein generally relates to a particulate shield, and more specifically, to a particulate shield for an actuator that moves a semiconductor device platform. Background Technology

[0004] The semiconductor and other similar industries typically use metrology or inspection equipment to evaluate substrates during processing, and semiconductor fabrication equipment to fabricate integrated circuits on wafers. During metrology or inspection, relative movement between the optical head and the substrate is often necessary, for example, to measure or inspect multiple areas on the substrate and to position the substrate at the appropriate focal point relative to the optical head. The same applies to fabrication equipment. Various types of platforms have been developed to rapidly position substrates at the desired measurement or inspection location relative to the optical head. For example, platforms can move the substrate (or optical head) using Cartesian (i.e., X and Y) coordinates, polar (i.e., R and θ) coordinates, or some combination of both. Additionally, platforms can move the substrate (or optical head) along a vertical (i.e., Z) coordinate for focusing or for loading and unloading substrates. Actuators can be used to generate the movement of the platform. However, actuators necessarily require physical movement between components and may generate particles. These particles may be small and sparse, but it is important to avoid particle contamination of substrates used in the semiconductor and similar industries. Utility Model Content

[0005] In some aspects, the technology described herein relates to a two-degree-of-freedom particle shield for an actuator housing, the actuator housing comprising a first Z-axis platform, a second Z-axis platform, and a Theta(θ) actuator that causes the first and second Z-axis platforms to rotate relative to the actuator housing. The particle shield may include a ring mounted on the actuator housing. The ring includes a flange coupled to the actuator housing and a collar extending from the flange along the Z-coordinate direction. The particle shield may also include a plate mounted to the first Z-axis platform. The plate includes a hole through which the second Z-axis platform passes. The plate also includes a skirt located at its outer periphery, the skirt extending along the Z-coordinate direction. The collar and the skirt are coaxial and do not contact each other during rotation of the first Z-axis platform, and remain in the same plane orthogonal to the Z-coordinate direction during movement of the first Z-axis platform along the Z-axis.

[0006] In some aspects, the technology described herein relates to a particulate shield for an actuator housing comprising a first Z-axis platform and a theta actuator that causes the first Z-axis platform to rotate relative to the actuator housing. The particulate shield may include a ring mounted on the actuator housing. The ring includes a flange coupled to the actuator housing and a collar extending from the flange in the Z-coordinate direction. The particulate shield may also include a plate mounted to the first Z-axis platform. The collar and the plate are coaxial and do not contact each other during rotation of the first Z-axis platform relative to the actuator housing, and remain in the same plane orthogonal to the Z-coordinate direction during movement of the first Z-axis platform in the Z-coordinate direction.

[0007] In some aspects, the technology described herein relates to a particulate shield for an actuator housing. The particulate shield may include a ring mounted on the actuator housing. The ring includes a flange coupled to the actuator housing and a collar extending from the flange along a Z-coordinate direction. The particulate shield may also include a plate mounted to a first Z-axis platform. The collar and the plate are held in the same plane orthogonal to the Z-coordinate direction and do not contact each other during movement of the first Z-axis platform in the Z-coordinate direction. Attached Figure Description

[0008] Figure 1 A schematic side view of a semiconductor device system including actuator components is shown.

[0009] Figure 2 Examples Figure 1 A perspective view of the actuator assembly shown in the figure.

[0010] Figure 3 A perspective view of a particle shield installed on an actuator assembly to reduce particulate contamination is shown.

[0011] Figure 4 A side view illustrates a portion of a particulate shield installed on an actuator assembly to reduce particulate contamination.

[0012] Figure 5A and Figure 5B Perspective views illustrating different specific implementations of the ring portion of the particle shield are shown.

[0013] Figure 6A and Figure 6B Perspective views illustrating different specific implementations of the plate portion of the particle shield are shown.

[0014] Figures 7A to 7E Side views illustrating different specific embodiments of rings and plates used for particle shielding are shown.

[0015] Figure 8A and Figure 8B Top views illustrating different specific implementations of rings and plates for particle shielding are shown. Detailed Implementation

[0016] During the metrology, fabrication, or inspection of semiconductor (or other similar) substrates, particulate contamination sources arise from moving parts within the platform that provide relative motion between the substrate and the optical head or tool. For example, during motion, materials within the internal volume of the platform (e.g., an actuator) rub against each other, generating particles. Additionally, particles from lubricants may be airborne. These particles may escape from the platform's internal volume and settle on the substrate, thus contaminating it.

[0017] The motion required in semiconductor devices can be complex. For example, while a platform can use Cartesian (i.e., X and Y) coordinates to move a substrate (or optical head), such motion requires a large area to reach all locations on the substrate. Polar (i.e., R and θ) coordinates are used to pre-align the Cartesian coordinates of the substrate with the Cartesian coordinates of the platform, but rotational motion is still required in addition to linear motion. Furthermore, motion along the Z-coordinate is used for focusing and for loading and unloading the substrate. Additionally, multiple platforms can be used to perform the same motion (e.g., a coarse-tuning motion platform and a fine-tuning motion platform). The resulting assembly can have multiple degrees of freedom (DOF), where each DOF can lead to particle generation and contamination of the substrate.

[0018] As discussed herein, a particle shield for an actuator housing of a platform can be used to reduce or eliminate the amount of particles escaping from the internal volume of the platform while allowing one or more DOFs of the platform. For example, the actuator housing may include a Z-axis platform for moving a substrate along the Z-axis, or may include both a Z-axis platform and a θ-coordinate platform for rotating the substrate in the θ direction. For example, the particle shield includes a ring having a flange coupled to the actuator housing and a collar extending from the flange along the Z-axis. The particle shield also includes a separate plate mounted to the Z-axis platform. The collar of the ring and the plate remain in the same plane but do not contact each other during movement of the Z-axis platform along the Z-axis. For example, the outer periphery of the plate may be positioned near the inner periphery of the collar (e.g., no more than 2 mm) and may be less than 1.5 mm, 1 mm, or 0.5 mm, but do not contact the collar during movement. In some specific embodiments, the inner periphery of the collar and the plate may be circular, thereby allowing the Z-axis platform to rotate (θ direction) without contacting each other. Additionally, the plate may include a skirt extending along the Z-axis at its outer diameter, wherein the collar and the skirt remain in the same plane during movement of the Z-axis platform along the Z-axis. The plate may also include a second Z-axis platform passing through a hole, for example, to allow both coarse and fine vertical movements.

[0019] As an example, Figure 1 This is a schematic side view of a semiconductor device system 100, which includes an actuator assembly 110 as a source of particulate contamination. The actuator assembly 110 is illustrated as realizing motion on the Z-axis (both coarse and fine adjustment motions) and rotational Theta(θ) motion, and is therefore sometimes referred to as a ZT box.

[0020] Semiconductor device system 100 is illustrated as including housing 102 and optical head or tool 104. Tool 104 may be a lithography camera, an optical system or other system for metrology / inspection, a drilling tool, an electroplating tool, an ion implantation tool, or any other metrology tool or semiconductor manufacturing tool. A chuck 106 for holding substrate 101 is illustrated as being mounted to actuator assembly 110. Additionally, as illustrated, semiconductor device system 100 may include a linear (R) platform 108 on which actuator assembly 110 is located. In some embodiments, platform 108 may generate movement along both the X and Y motion coordinates.

[0021] Actuator assembly 110 includes an outer housing 112 containing a first (e.g., fine-tuning) Z-axis platform 120, a second (e.g., coarse-tuning) Z-axis platform 130, and an θ actuator 140. The θ actuator 140 is operable to rotate both the first Z-axis platform 120 and the second Z-axis platform 130, exemplified by the Theta (θ) coordinate. Additionally, as illustrated, the first Z-axis platform 120 is mounted to the θ actuator 140, which is mounted to the Z (fine-tuning) actuator 122, which operates to move the first Z-axis platform 120, the θ actuator 140, and the second Z-axis platform 130 along the Z-coordinate direction. The second Z-axis platform 130 is mounted on the second Z (coarse-tuning) actuator 132, which operates to move the second Z-axis platform 130 along the Z-coordinate direction. The suction cup 106 is illustrated as being mounted on the second Z-axis platform 130.

[0022] Additionally, as illustrated, a plurality of lifting pins 124 may be coupled to the first Z-axis platform 120 and may pass through the suction cup 106. When the second Z-platform 130 descends, thereby causing the suction cup 106 to descend, the lifting pins 124 will rise above the top surface of the suction cup 106 to load or unload the substrate 101 from the suction cup, for example by allowing a paddle to enter to transport the substrate 101 to and from the suction cup 106.

[0023] It should be understood that actuator assembly 110 is exemplary, and actuator assemblies may have other configurations. For example, the types of platforms and actuators may vary. For example, actuator assembly 110 is illustrated as having two DOFs (Z and θ), but may have a single DOF (e.g., Z or θ). Furthermore, actuator assembly 110 may include only a single Z-axis platform (e.g., platform 120). In some specific embodiments, the order of the platform and actuators may vary. For example, the θ actuator 140 is illustrated as being mounted between the Z (fine-tuning) actuator 122 and the Z (coarse-tuning) actuator 132; however, in some embodiments, the first Z-axis platform 120 may be mounted to the Z (fine-tuning) actuator 122, and the θ actuator 140 may be mounted below both the Z (fine-tuning) actuator 122 and the Z (coarse-tuning) actuator 132, or the Z actuator 122 may be a coarse-tuning motion actuator, and the Z actuator 132 may be a fine-tuning motion actuator.

[0024] As an example, Figure 2 yes Figure 1 The perspective view of actuator assembly 110 shown illustrates the outer housing 112, the first Z-axis platform 120, and the second Z-axis platform 130. Figure 2Z-actuators 122 and 132 and θ-actuator 140 are not shown. As illustrated, the second Z-axis platform 130 may include mounting holes 134 through which the chuck 106 can be mounted (e.g., bolted) to the second Z-axis platform 130. Additionally, the second Z-axis platform 130 includes a hole 136 and a washer 138, which can be used to apply a vacuum to the chuck 106 (if needed) to hold the substrate. A lifting pin 124 may be mounted on a tab 126 to the first Z-axis platform 120. For example, the tab 126 may allow the lifting pin 124 to be mounted at different locations (radii) to accommodate different chuck designs. As illustrated, the housing 112 may include a cutout 117 larger than the tab 126 to allow the first Z-axis platform 120 to move the tab 126 below the top surface of the housing 112.

[0025] Particulate contamination sources from actuator assembly 110 include moving parts (such as actuators 122, 132, and 140). Figure 1 As shown in the diagram, and platforms 120 and 130), these moving parts may generate particles through friction with other components. Additionally, particles from the lubricant may be transmitted through the air. Figure 1 As illustrated by arrow 111, particles generated within actuator assembly 110 can be placed in the space 150 between housing 112 and moving part (e.g., platform 120). Figure 1 and Figure 2 Particles may escape between the housing 112 and the platform 120 (as illustrated in the diagram), and may fall onto the substrate 101 and contaminate it. A vacuum may be applied to the internal volume of the housing 112, for example, in an attempt to expel any generated particles from the housing 112. For a relatively large space 150, there may be insufficient contraction between the housing 112 and the platform 120, and a vacuum may be insufficient to prevent particles from escaping the housing along the path illustrated by arrow 111.

[0026] The particle shield includes a ring and a separate plate. The ring is mounted to the actuator housing 112 and the plate is mounted to the Z-axis platform 120. The particle shield can be used to improve the discharge of particles from the housing 112 by reducing the cross-sectional area through which particulate contaminants can leave the housing 112 and by increasing the pressure difference between the internal volume of the housing 112 and the ambient atmosphere (outside the housing 112), thereby significantly reducing particulate contamination of the substrate 101.

[0027] As an example, Figure 3 Is it installed to Figure 1 and Figure 2 The image shows a perspective view of the particle shield 300 of the actuator assembly 110, and... Figure 4 A side view of a portion of a particle shield 300 mounted to actuator assembly 110 to reduce particulate contamination is shown.

[0028] As illustrated in the figure, the particle shield 300 includes a ring 310 with a flange 312, which is secured by screws or bolts 313. Figure 3 (as shown in the figure) or other suitable mounting members are mounted to the housing 112 (e.g., the top surface of the housing 112). The ring 310 also includes a collar 314 that extends from the flange 312 along the Z-axis direction. As illustrated in the figure, in Figure 3 In the original design, the collar 314 can extend upward in the Z direction, but in the modification of the collar 310, the collar 314 can extend downward in the Z direction.

[0029] The particle shield 300 also includes a plate 320, which is mounted to a Z-axis platform 120, the Z-axis platform being... Figure 4 It is shown in the middle but Figure 3 The plate 320 may be obscured and not visible. The plate 320 may include a cover 322, which may include a hole 321 through which the second Z-axis platform 130 (if present) passes. Figure 3 Hole 321 is illustrated as circular to accommodate a circular second Z-axis platform 130; however, it should be understood that the second Z-axis platform 130 may have other geometries (e.g., square, triangle, etc.), and hole 321 will have a corresponding shape to accommodate the shape of the second Z-axis platform 130. Plate 320 may be secured using screws or bolts 323. Figure 3 (as shown in) or other suitable mounting components (e.g., in) Figure 2 The plate 320 (shown as tab 126) is mounted to the Z-axis platform 120. A lifting pin 124 mounted to the Z-axis platform 120 may extend through a hole in the plate 320. The plate 320 may include a skirt 324 located at the outer periphery of the plate 320, extending in the Z-coordinate direction. Typically, the skirt 324 may extend in the opposite direction to the collar 314. The skirt 324 and the collar 314 may be concentric to allow the plate 320 (e.g., the skirt 324) to rotate within the collar 314 without contact during rotation of the Z-axis platform 120 relative to the housing 112 generated by the θ actuator 140. Additionally, the lengths of the skirt 324 and the collar 314 are configured such that they do not contact the housing 112 or the suction cup 106, for example, as shown in the figure. Figure 4 As illustrated, throughout the entire Z-coordinate movement range of the Z-axis platform 120, the collar 314 does not contact the suction cup 106 and the skirt 324 does not contact the housing 112. Furthermore, the plate 320 (e.g., the skirt 324) and the collar 314 are configured such that the plate 320 (e.g., the skirt 324) and the collar 314 remain orthogonal to the Z-axis (by...) during the entire Z-coordinate movement range of the Z-axis platform 120. Figure 4(Illustrated by dashed line 327) In the same plane. The space 350 between plate 320 (e.g., skirt 324) and collar 314 may not exceed 2 mm, and may be less than 1.5 mm, 1 mm, or 0.5 mm. The tight relationship between plate 320 (e.g., skirt 324) and collar 314 reduces the cross-sectional area of ​​the space 350 through which particles can exit the housing 112 (illustrated by arrow 113). Furthermore, when a vacuum 115 is applied to the internal volume of housing 112, the tight relationship between plate 320 (e.g., skirt 324) and collar 314 increases the pressure difference between the internal volume of housing 112 and the ambient atmosphere (outside housing 112), which improves the discharge of particles from housing 112.

[0030] Ring 310 and plate 320 may be made of the same or different materials, such as aluminum (which may be anodized or plated, for example, by electroless nickel plating or other plating methods), steel, stainless steel, or polymers (such as polytetrafluoroethylene (PTFE), polyoxymethylene (POM), polyetheretherketone (PEEK)). Plate 320, mounted on the moving Z-axis platform 120, should therefore have a sufficiently small mass (e.g., thickness and / or material) to have an insignificant effect on the performance characteristics of actuators 122, 140, and / or may require modification of the motion curve parameters of one or both actuators 122 and 140 to accommodate the additional mass and moment of inertia of plate 320. Additionally, the thickness and / or material of plate 320 should provide sufficient stiffness to prevent undesirable vibrations.

[0031] As an example, Figure 5A yes Figure 3 and Figure 4 The image shows a perspective view of the ring 310 portion of the particle shield 300. The ring 310 may be a single unit comprising a flange 312 and a collar 314, illustrated as extending upward from the flange 312 (e.g., along the Z-axis). The flange 312 is illustrated as having a circular outer diameter but may have any desired shape. The flange 312 may include provisions for screws or bolts 313 (…). Figure 3 (As shown in the diagram) a plurality of holes 311 are used to fasten the ring 310 to the housing 112 of the actuator assembly 110. The collar 314 is illustrated as having a circular inner periphery, which causes the circular plate 320 ( Figure 3 and Figure 4 (As shown in the diagram) It can rotate along the Theta (θ) coordinate. If needed, without using the rotation of plate 320 relative to ring 310 (i.e., the Z-axis platform plate 120 relative to...), Figure 4 In the case of rotation of the housing 112 shown in the figure, the inner periphery of the collar 314 may have other geometries.

[0032] As an example, Figure 5BThis is a perspective view of another specific embodiment of the ring 310' portion of the particle shield 300. Figure 5B The ring 310' shown in the example is similar to Figure 5A The ring 310 illustrated includes a flange 312 with a hole 311 and an upwardly extending collar 314. However, unlike ring 310, ring 310' is formed by separate segments. For example, as... Figure 5B As illustrated, ring 310 may include two separable segments 310A and 310B, which are connected via tabs 316 extending from flanges 312 and collars 314 of each segment 310A and 310B. When mounted on housing 112 of actuator assembly 110, the tabs 316 from segments 310A and 310B may be press-fitted together or otherwise coupled together. Using multiple separable segments to form ring 310' has the advantages of ease of assembly and simplified use of calibration screws (e.g., wedge locking screws and oscillating locking screws) on actuator assembly 110 (not shown) that may otherwise be obscured by ring 310'.

[0033] As an example, Figure 6A yes Figure 3 and Figure 4 The image shows a perspective view of a plate 320 portion of the particle shield 300 illustrated herein. Plate 320 may be a single unit comprising a cover 322 and a skirt 324, illustrated as extending downward from the cover 322 (e.g., along the Z-axis). The cover 322 may include a hole 321 through which a second Z-axis platform 130 (if present) passes. Plate 320 may include means for screws or bolts 323 (…). Figure 3 (As shown in the diagram) A plurality of holes 325 secure the plate 320 to the Z-axis platform 120. Additionally, the plate 320 may include a plurality of holes 326 through which a lifting pin 124 can pass. The plate 320 (e.g., skirt 324) is illustrated as having a circular outer periphery that allows the plate 320 to rotate in the Theta(θ) coordinate within the collar 314 of the ring 310. If desired, rotation of the plate 320 relative to the ring 310 (i.e., the Z-axis platform plate 120 relative to the ring 310) can be used without rotation of the plate 320 relative to the ring 310. Figure 4 In the case of rotation of the housing 112 shown in the figure, the outer periphery of the plate 320 (e.g., the skirt 324) may have other geometries that match the inner periphery of the collar 314.

[0034] As an example, Figure 6B This is a perspective view of another specific embodiment of the plate 320' portion of the particle shield 300. Figure 6B The plate 320' shown in the example is similar to Figure 6AThe plate 320 illustrated includes a cover 322 and holes 321, 325, and 326. However, unlike plate 320, plate 320' does not include a downwardly extending skirt. For example, the outer periphery of plate 320 may serve as a skirt. In some embodiments, it may be desirable for plate 320' to be relatively thick, for example, compared to plate 320, to compensate for the lack of a skirt.

[0035] As an example, Figures 7A to 7E Examples of various specific implementations are provided. Figure 3 and Figure 4 The image shows a side view of the ring and plate used together with the particle shield 300.

[0036] For example, Figure 7A An example is illustrated by a ring 710A and a plate 720A, the ring having an upwardly extending collar 714A at the inner periphery of a flange 712A, and the plate having a downwardly extending skirt 724A at the outer periphery of a cover 722A. As illustrated, the skirt 724A is positioned inside the collar 714A. Figure 7A A further example is plane 701A, orthogonal to the Z direction, in which ( Figure 4 During the vertical movement of plate 720A (illustrated by double arrows) caused by the movement of Z-axis platform 120 (shown in the diagram), both collar 714A and skirt 724A remain across the plane.

[0037] Figure 7B An example is illustrated by a ring 710B and a plate 720B, the ring having an upwardly extending collar 714B at the inner periphery of a flange 712B, and the plate having a downwardly extending skirt 724B at the outer periphery of a cover 722B. As illustrated, the skirt 724B is positioned outside the collar 714B. Figure 7B A further example is the plane 701B, orthogonal to the Z direction, in which ( Figure 4 During the vertical movement of plate 720B (illustrated by double arrows) caused by the movement of Z-axis platform 120 (shown in the diagram), both collar 714B and skirt 724B remain across the plane.

[0038] Figure 7C An example is illustrated by a ring 710C and a plate 720C, the ring having an upwardly extending collar 714C at the outer periphery of a flange 712C, and the plate having a downwardly extending skirt 724C at the outer periphery of a cover 722C. As illustrated, the skirt 724C is positioned inside the collar 714C. Figure 7C A further example is the plane 701C, orthogonal to the Z direction, in which ( Figure 4 During the vertical movement of plate 720C (illustrated by double arrows) caused by the movement of Z-axis platform 120 (shown in the diagram), both collar 714C and skirt 724C remain across the plane.

[0039] Figure 7D An example is illustrated by a ring 710D and a plate 720D, the ring having an upwardly extending collar 714D at the outer periphery of a flange 712D, and the plate having a downwardly extending skirt 724D at the outer periphery of a cover 722D. As illustrated, the skirt 724D is positioned outside the collar 714D. Figure 7D A further example is the plane 701D orthogonal to the Z direction, in which ( Figure 4 During the vertical movement of plate 720D (illustrated by double arrows) caused by the movement of Z-axis platform 120 (shown in the diagram), both collar 714D and skirt 724D remain across the plane.

[0040] Figure 7E An example is illustrated with a ring 710E and a plate 720E, the ring having an upwardly extending collar 714E at the inner periphery of a flange 712E, and the plate comprising only a cover 722E without a skirt. As illustrated, the outer periphery of the cover 722E is positioned inside the collar 714E. Figure 7E A further example is the plane 701E, orthogonal to the Z direction, in which ( Figure 4 During the vertical movement of plate 720E (illustrated by double arrows) caused by the movement of Z-axis platform 120 (shown in the diagram), both collar 714E and cover 722E remain across the plane.

[0041] As an example, Figure 8A and Figure 8B Examples of various specific implementations are provided. Figure 3 and Figure 4 The image shows a top view of the ring and plate used together with the particle shield 300. It should be understood that... Figure 8A or Figure 8B The specific implementation illustrated herein may be related to Figures 7A to 7E Any of the specific implementations exemplified herein may be used in combination.

[0042] For example, Figure 8A An example is illustrated with a ring 810A and a plate 820A, the ring having a collar 814A at the inner periphery of a flange 812A, and the plate including a skirt (not shown) at the outer periphery of a cover 822A. The cover 822A (or the skirt, if present) is positioned inside the collar 814A. Figure 8AAs illustrated, the inner peripheries of plate 820A, ring 810A, and collar 814A are circular and separable by no more than 2 mm, and may be less than 1.5 mm, 1 mm, or 0.5 mm, to reduce the cross-sectional area through which particles can exit. The outer periphery of cover 822A (e.g., the outer periphery of skirt, if present) and the inner periphery of collar 814A are coaxial, for example, both centered at the same center point 801A, which allows plate 820A to rotate non-contactly within collar 814A, as illustrated by the double arrows. Therefore, both rotational and vertical movements along the Z-axis are possible, thus achieving a particle shield with two degrees of freedom.

[0043] Figure 8B An example is illustrated by a ring 810B and a plate 820B, the ring having a collar 814B at the inner periphery of a flange 812B, the plate including a skirt (not shown) at the outer periphery of a cover 822B. The cover 822B (or the skirt, if present) is positioned inside the collar 814B. Figure 8B As illustrated, the outer periphery of the plate 820B and ring 810B, and more specifically, the outer periphery of the cover 822B (e.g., the outer periphery of the skirt, if present) and the inner periphery of the collar 814B are not circular, but rather triangular in shape. The outer periphery of the cover 822B (e.g., the outer periphery of the skirt, if present) and the inner periphery of the collar 814B may have geometries other than triangular or circular, but they should be identical in shape. The outer periphery of the cover 822B (e.g., the outer periphery of the skirt, if present) and the inner periphery of the collar 814B may be separated by no more than 2 mm, and may be less than 1.5 mm, 1 mm, or 0.5 mm, to reduce the cross-sectional area through which particles can exit. When using geometries other than circular, rotational movement of the plate 820B relative to the ring 810B is not possible, but vertical movement along the Z-axis is possible, thus achieving a particle shield with a single degree of freedom.

[0044] The above description is intended to be illustrative and not restrictive. For example, the examples (or one or more aspects thereof) described above may be used in combination with each other. Other specific embodiments may be used by those skilled in the art after reading the above description. Furthermore, various features may be grouped together, and fewer than all features of a particular disclosed specific embodiment may be used. Therefore, the following aspects are thus incorporated into the above description as examples or specific embodiments, each aspect being an independent, separate specific embodiment, and it is contemplated that such specific embodiments may be combined or arranged in various ways with each other. Therefore, the substance and scope of the appended claims should not be limited to the foregoing description.

Claims

1. A particle shield with two degrees of freedom for an actuator housing, the actuator housing comprising a first Z-axis platform, a second Z-axis platform, and a θ actuator, the θ actuator causing the first Z-axis platform and the second Z-axis platform to rotate relative to the actuator housing, the particle shield comprising: A ring, which is mounted on the actuator housing, includes a flange and a collar, the flange being connected to the actuator housing and the collar extending from the flange along the Z-coordinate direction; and A plate, the plate being mounted to a first Z-axis platform, the plate including a hole through which a second Z-axis platform passes and a skirt extending along the Z-coordinate direction at the outer periphery of the plate, wherein the collar and the skirt are coaxial and do not contact each other during rotation of the first Z-axis platform, and the collar and the skirt remain in the same plane orthogonal to the Z-coordinate direction during movement of the first Z-axis platform along the Z-coordinate direction.

2. The particle shielding body according to claim 1, wherein the skirt is located inside the collar.

3. The particle shielding body according to claim 1, wherein the collar is located inside the skirt.

4. The particle shielding body according to claim 1, wherein the collar is circular and the skirt is circular.

5. The particle shielding body according to claim 1, wherein the gap between the collar and the skirt does not exceed 2 mm.

6. The particle shielding body according to claim 1, wherein the skirt and the collar remain in the same plane throughout the entire range of motion of the first Z-axis platform along the Z-coordinate direction.

7. The particle shielding body according to claim 1, wherein the plate further includes a plurality of holes through which lifting pins extend.

8. The particle shielding body according to claim 1, wherein the suction cup is mounted to the second Z-axis platform.

9. A particle shield for an actuator housing, the actuator housing including a first Z-axis platform and a θ actuator, the θ actuator causing the first Z-axis platform to rotate relative to the actuator housing, the particle shield comprising: A ring, which is mounted on the actuator housing, includes a flange and a collar, the flange being connected to the actuator housing and the collar extending from the flange along the Z-coordinate direction; and A plate is mounted to the first Z-axis platform, wherein the collar and the plate are coaxial and do not contact each other during rotation of the first Z-axis platform relative to the actuator housing, and the collar and the plate remain in the same plane orthogonal to the Z-coordinate direction during movement of the first Z-axis platform in the Z-coordinate direction.

10. The particle shielding body according to claim 9, wherein the outer periphery of the plate and the collar are coaxial and the outer periphery of the plate and the collar do not contact each other during rotation of the first Z-axis platform.

11. The particle shielding body according to claim 9, wherein the distance between the outer periphery of the plate and the collar does not exceed 2 mm.

12. The particle shielding body according to claim 9, wherein the plate and the collar are maintained in the same plane throughout the entire range of motion of the first Z-axis platform along the Z-coordinate direction.

13. The particle shielding body of claim 9, wherein the plate further includes a hole through which a second Z-axis platform passes.

14. The particle shielding body according to claim 13, wherein the suction cup is mounted to the second Z-axis platform.

15. The particle shielding body of claim 9, wherein the plate further includes a plurality of holes through which lifting pins extend.

16. A particulate shield for an actuator housing, the particulate shield comprising: A ring, which is mounted on the actuator housing, includes a flange and a collar, the flange being connected to the actuator housing and the collar extending from the flange along the Z-coordinate direction; and A plate is mounted to a first Z-axis platform, wherein the collar and the plate are held in the same plane orthogonal to the Z-coordinate direction, and the collar and the plate do not contact each other during movement of the first Z-axis platform in the Z-coordinate direction.

17. The particle shield of claim 16, wherein the actuator housing includes a theta actuator that rotates the first Z-axis platform relative to the actuator housing, wherein the plate and the collar are coaxial and do not contact each other during rotation of the first Z-axis platform.

18. The particle shielding body of claim 16, wherein the outer periphery of the plate includes a skirt extending along the Z-coordinate direction, and the collar and the skirt remain in the same plane during movement of the first Z-axis platform in the Z-coordinate direction.

19. The particle shielding body according to claim 16, wherein the distance between the outer periphery of the plate and the collar does not exceed 2 mm.

20. The particle shield of claim 16, wherein the plate further includes a plurality of holes through which lifting pins extend.

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