Lifter assembly with guide tube for optical inspection system

Abstract

This invention discloses a lifter assembly for an optical system, comprising a chuck with a chuck base and a removable top plate, wherein the removable top plate is one of a plurality of replaceable removable top plates configured to support a substrate. The lifter assembly further includes a movable plate for supporting the chuck on its upper surface, the movable plate being vertically adjustable between a retracted position and an extended position. The lifter assembly further includes a guide tube structure operatively coupled to the movable plate. The lifter assembly further includes a pneumatic system fluidly coupled to the guide tube structure for selective expansion and contraction, wherein expansion of the guide tube structure vertically adjusts the movable plate to the extended position, and contraction of the guide tube structure vertically adjusts the movable plate to the retracted position.

Description

[0001] Cross-reference of related applications

[0002] This application claims priority to U.S. Provisional Application No. 63 / 430,412, filed December 6, 2022, the disclosure of which is incorporated herein by reference in its entirety. Technical Field

[0003] The embodiments described herein relate to optical inspection systems, and more specifically, to a pneumatic lift assembly for such systems. Background Technology

[0004] Inspection processes are used at various stages during semiconductor manufacturing to detect defects on wafers, thereby improving manufacturing yield and ultimately increasing profits. Inspection has always been a crucial part of manufacturing semiconductor devices. However, as the size of semiconductor devices shrinks, inspection becomes even more critical to the successful manufacture of acceptable semiconductor devices, as even smaller defects can cause device failure.

[0005] Some manufacturing, measurement, and defect inspection processes require a chuck that vertically moves a substrate positioned on its top surface. A lifter assembly supports the chuck and actuates its vertical movement. For example, a pneumatic rod may be located within the lifter assembly's chamber and connected to a support feature and a movable plate to perform vertical movement of the chuck by introducing and removing fluid. Some tools that work with the lifter assembly can provide limited space during operation to accommodate all lifter assembly features. The aforementioned pneumatic rod occupies more space when the lifter assembly extends from its retracted (i.e., downward) position to its upward position. Furthermore, the pneumatic rod cannot maintain perpendicularity to its adjacent support feature when lifting or applying uneven loads, leading to wear within the hole through which the rod slides. Finally, the pneumatic rod can only extend to a fixed, non-adjustable stroke length.

[0006] The aforementioned issues pose challenges to the substrate inspection process. Summary of the Invention

[0007] According to one aspect of the invention, a lifter assembly for an optical system includes a chuck having a chuck base and a removable top plate, wherein the removable top plate is one of a plurality of replaceable removable top plates configured to support a substrate. The lifter assembly further includes a movable plate for supporting the chuck on an upper surface of the movable plate, the movable plate being vertically adjustable between a retracted position and an extended position. The lifter assembly further includes a guide tube structure operatively coupled to the movable plate. The lifter assembly further includes a pneumatic system fluidly coupled to the guide tube structure for selective expansion and contraction, wherein expansion of the guide tube structure vertically adjusts the movable plate to the extended position and contraction of the guide tube structure vertically adjusts the movable plate to the retracted position.

[0008] According to another aspect of the invention, an optical system includes a substrate chuck system having a chuck with a chuck base and a removable top plate configured to support a substrate. The optical system further includes a movable plate for supporting the chuck on an upper surface of the movable plate, the movable plate being vertically adjustable between a retracted position and an extended position. The optical system further includes a guide tube structure operatively coupled to the movable plate, wherein expansion of the guide tube structure vertically adjusts the movable plate to the extended position and contraction of the guide tube structure vertically adjusts the movable plate to the retracted position. The optical system further includes an illumination source configured to illuminate one or more portions of the substrate. The optical system also includes a detector configured to collect illumination from the illuminated portions of the substrate.

[0009] According to another aspect of the invention, a lifter assembly for vertically repositioning a substrate includes a vacuum chuck configured to support the substrate and hold it in place by vacuum pressure. The lifter assembly further includes a movable plate to support the vacuum chuck on an upper surface of the movable plate, the movable plate being vertically adjustable between a retracted position and an extended position. The lifter assembly further includes a welded guide tube structure operatively coupled to the movable plate, wherein expansion of the welded guide tube structure vertically adjusts the movable plate to the extended position and contraction of the guide tube structure vertically adjusts the movable plate to the retracted position.

[0010] These aspects and other advantages and features will become clear from the following description taken in conjunction with the accompanying drawings. Attached Figure Description

[0011] The objectives of embodiments of the present invention are specifically pointed out and expressly claimed in the claims at the end of this specification. The features and advantages of the disclosed embodiments will become clear from the following detailed description taken in conjunction with the accompanying drawings, wherein:

[0012] Figure 1 This is a partial cross-sectional front view of the lifting assembly of the optical inspection system that supports the chuck;

[0013] Figure 2 This is a perspective view of the elevator assembly;

[0014] Figure 3A Describe the elevator assembly in the retracted position and its connected fluid lines;

[0015] Figure 3B Describe the lifting assembly and its connected fluid lines in the extended position;

[0016] Figure 4A Description of the lifting assembly in the retracted position;

[0017] Figure 4B Explain the lifting assembly in the extended position;

[0018] Figure 5 This is a cross-sectional front view of a lifting assembly according to another aspect of the present invention;

[0019] Figure 6A An illustrative description of an optical system according to an embodiment of the lift assembly disclosed herein, based on one aspect of the present invention; and

[0020] Figure 6B An optical system according to an embodiment of the lift assembly disclosed herein, based on another aspect of the present invention, is illustrated. Detailed Implementation

[0021] Referring to the figures, when the invention is described with reference to specific embodiments, it should be understood that the disclosed embodiments are merely examples of the invention that may be embodied in various and alternative forms. The figures are not necessarily drawn to scale, as some features may be enlarged, reduced, or simplified to show details of specific components. Therefore, the specific structural and functional details disclosed herein and illustrated in the figures should not be construed as limiting, but are merely representative bases for teaching those skilled in the art to employ the invention in different ways.

[0022] refer to Figure 1A portion of a substrate chuck system for optical systems is shown and is generally referred to by element symbol 11. An embodiment of the lift assembly 10 is disclosed herein as supporting and vertically adjusting the chuck 14. The lift assembly 10 includes a movable plate 12 supporting the chuck 14. The chuck 14 is configured to support a substrate, for example, a semiconductor wafer (not shown). Various types of contemplated chucks may be used with the lift assembly 10 disclosed herein. By a non-limiting example, the lift assembly 10 may be used with the substrate chuck system disclosed in U.S. Patent Application No. 17 / 562,544, the disclosure of which is incorporated herein by reference in its entirety. In the illustrated embodiment, the chuck 14 is a vacuum chuck that holds the substrate in place on the top surface 13 of the chuck 14, wherein vacuum pressure is routed through the chuck 14 via one or more vacuum inlets 15 and a vacuum reservoir 17. Additionally, in the illustrated embodiment, the chuck 14 includes a chuck base 16 and a removable plate 18. The removable plate 18 is secured to the chuck base 16 via one or more fasteners or guides 20. However, it should be understood that having a single-structure chuck 14 is within the scope of the disclosed embodiments.

[0023] The chuck base 16 is structured to advantageously allow different types of removable plates 18 to be secured thereto. The removable plates 18 are adapted for quick replacement on the chuck base 16. This configuration is more time- and cost-effective during substrate chuck replacement because it allows a common chuck base to accommodate multiple top plates for various substrates.

[0024] Regardless of the specific type of chuck, integral tool / stage, and optical system, embodiments of the lift assembly 10 disclosed herein include a guide tube structure 22, which actuates the movable plate 12 and thus the chuck 14 and a substrate supported on the chuck for substantially vertical movement. In some embodiments, the guide tube structure 22 is of the welded guide tube type. The guide tube structure 22 is formed as a folded structure such that a plurality of annular guide tube plates with radial curvature are alternately connected on the outer diameter side and the inner diameter side. The guide tube plates are joined together by TIG welding or the like in, for example, an atmospheric or Ar gas environment. The guide tube structure 22 defines a hollow internal chamber.

[0025] The vertical adjustment of the movable plate 12 changes the distance between the chuck 14 (on which the substrate is held) and the measuring device of the optical system. As used herein, the term "measuring device" is generally used to refer to a measuring device, an inspection device, or a combination of measuring and inspection devices. The vertical adjustment of the movable plate 12, the chuck 14, and the substrate facilitates various operations of the optical system.

[0026] For reference Figure 2Additionally, the lifting assembly 10 is shown in detail. As shown, in the illustrated embodiment, the fasteners and guides 20 are radially outward from the vacuum inlet 15, which is consistent with... Figure 1 The configuration shown is the opposite of the one described above. Therefore, it should be understood that either configuration can be considered.

[0027] In the illustrated embodiment, the movable plate 12 has a central portion 24 and a plurality of arms 26 extending from the central portion 24. Specifically, the illustrated embodiment has three arms, but it should be understood that alternative numbers of arms may exist in other embodiments. The lifter assembly 10 also includes a base flange 28 and a top cover 30. A plurality of guide shafts 32 each extend through a corresponding hole in the movable plate 12 and are operatively coupled to the base flange 28 and the top cover 30. Each guide shaft 32 may have a threaded end for engaging a threaded area of ​​the base flange 28 and the top cover 30. Alternatively, the guide shafts 32 may be coupled to the base flange 28 and the top cover 30 via a nut or the like. When the guide tube structure 22 actuates the vertical adjustment of the movable plate 12, the chuck 14, and the substrate, the guide shafts 32 guide vertical movement to maintain adjustment in the vertical direction. The number of the plurality of guide shafts 32 may vary depending on the specific application.

[0028] For reference Figure 3A and 3B Continue to refer to Figure 2 The lifter assembly 10 is fluidly coupled to the pneumatic system 40. A first fluid connection is formed via a first conduit arrangement 42 between at least one of the plurality of arms 26 of the movable plate 12. The first fluid connection provides the vacuum pressure required to hold the substrate on the chuck 14, as described above. A second fluid connection is formed via a second conduit arrangement 48 between the internal chamber of the port tube structure 22 and a selectively switchable supply from a compressed air source 44 and a vacuum pressure source 46. With respect to the second fluid connection, the open solenoid 50 has: an inlet 52 for receiving compressed air from the compressed air source 44; an outlet 54 for routing compressed air to the internal chamber of the port tube structure 22; and a discharge port 56 for extracting compressed air from the internal chamber of the port tube structure 22 via the vacuum pressure source 46.

[0029] In the illustrated embodiment, the open solenoid 50 is a 3-way solenoid; however, it should be understood that other types of piping arrangements may be used for the second fluid connection to selectively route compressed air into and out of the internal chamber of the port structure 22. In the illustrated embodiment of the open solenoid 50, when the open solenoid 50 is de-energized, vacuum pressure is supplied to the port structure 22 to contract the port structure 22, thereby lowering the movable plate 12. Conversely, when the open solenoid 50 is energized, compressed air enters the port structure 22 through a pressure regulator 58 preset to a pressure value sufficient to expand the port structure 22, thereby increasing the mobility of the movable plate 12, the chuck 14, and the substrate supported thereon.

[0030] refer to Figure 4A and 4B The lifting assembly 10 according to the first embodiment is described in more detail. The guide tube structure 22 can be in the lower retracted position ( Figure 4A ) and the upper extension position ( Figure 4B Vertical adjustment is made between the movable plate 12, chuck 14, and substrate to vertically adjust them. As described above, a plurality of guide shafts 32 extend through corresponding holes in the movable plate 12 and are operatively coupled to the base flange 28 and the top cover 30 to guide the vertical movement of the movable plate 12. Stable movement of the movable plate 12 during vertical translation along the guide shafts 32 is provided by a plurality of bushing arrangements 60. Specifically, the movable plate 12 has several bushing arrangements 60 mounted on its upper surface 62, corresponding to the number of guide shafts 32. Thus, each guide shaft 32 passes through a corresponding bushing arrangement 60. Each bushing arrangement 60 includes a bushing housing 64 containing bushings 68. The bushing arrangements 60 concentrically surround a portion of the guide shaft 32 and translate together with the movable plate 12.

[0031] The lower retracted position of the lifting assembly 10 ( Figure 4A ) and the upper extension position ( Figure 4B The corresponding upper and lower stop structures are defined as described herein. The disclosed stop structures provide predefined limits on the vertical travel of the guide tube structure 22, the movable plate 12, the chuck 14, and therefore the substrate held thereon.

[0032] The upper extension position is defined by the contact between the upper travel limiting feature 70 and the upper stop 72, which is operatively coupled to or integrally formed with the movable plate 12. In some embodiments, the upper travel limiting feature 70 is integrally formed with the top cover 30 and is part of the lower surface 74 of the top cover 30. In other embodiments, the upper travel limiting feature 70 is a component separate from and operatively coupled to the top cover 30, as described. For example, the upper travel limiting feature 70 may be directly screwed to the top cover 30 or coupled to the top cover 30 by mechanical fasteners. The upper travel limiting feature 70 is positioned to contact the upper stop 72, which extends upward from the upper surface 62 of the movable plate 12. As mentioned above, the upper stop 72 may be integrally formed with the movable plate 12. In embodiments where the upper stop 72 is operatively coupled to the movable plate 12, the upper stop 72 may have a coupling section 76 extending through the movable plate 12 to engage with it, or may extend completely through the movable plate 12 to couple to an upper flange 78 disposed below the movable plate 12. Either of the embodiments disclosed herein results in contact between the upper travel limiting feature 70 and the upper stop 72 to define an upper extended position of the movable plate 12.

[0033] The lower retracted position is defined by the contact between the lower travel limiting feature 80 and the lower stop 82, which is operatively coupled to or integrally formed with the movable plate 12. In the illustrated embodiment, the upper flange 78 includes a body portion 84 disposed between the top of the guide tube structure 22 and the movable plate 12. The upper flange 78 also includes a downwardly projecting portion, which in the illustrated embodiment is the lower stop 82. The lower stop 82 is positioned to contact an upwardly projecting portion of the base flange 28, which in the illustrated embodiment is the lower travel limiting feature 80. The contact between the lower stop 82 and the lower travel limiting feature 80 defines the lower retracted position of the movable plate 12. It should be understood that in alternative embodiments, the lower travel limiting feature 80 may be an assembly operatively coupled to the base flange 28 rather than integrally formed with it. Similarly, in other embodiments, the lower stop 82 is operatively coupled to either the upper flange 78 or the movable plate 12.

[0034] For reference Figure 5 The slider assembly 90 is provided as Figure 4A and 4BThe multiple guide shafts 32 and bushing arrangements 60 shown are alternatives. The slider assembly 90 includes multiple slide rails 92 extending through corresponding holes defined by the movable plate 12. Each of the slide rails 92 is operatively coupled to the base flange 28 and the top cover 30. Each slide rail 92 may have a threaded end for engaging the threaded area of ​​the base flange 28 and the top cover 30. Alternatively, the slide rails 92 may be coupled to the base flange 28 and the top cover 30 via a nut or the like. When the guide tube structure 22 actuates the vertical adjustment of the movable plate 12, the chuck 14, and the substrate, the slide rails 92 guide vertical movement to maintain vertical adjustment. The number of slide rails 92 may vary depending on the specific application.

[0035] A plurality of mounting plates 94, corresponding to the number of slide rails 92, are coupled to the upper surface 62 of the movable plate 12. Each of the mounting plates 94 has a sliding member 96 disposed between the respective mounting plate 94 and the slide rail 92. Thus, during vertical movement of the movable plate 12, the slider assembly 90 ensures smooth guided movement of the movable plate 12.

[0036] For reference Figure 6A and 6B This illustrates a simplified schematic diagram of an optical system 200, 210 equipped with the lift assembly 10 and chuck 14 previously described herein. In one embodiment, the optical system 200, 210 further includes at least one light source 202 (e.g., one or more lasers, one or more broadband light sources, etc.) configured to illuminate a region on the surface of a substrate. In another embodiment, the optical system 200, 210 includes one or more detectors 204 or cameras adapted to detect light reflected, diffracted, or scattered from the region illuminated by the light source 202. In one embodiment, the one or more detectors 204 may include, but are not limited to, CCD or TDI-CCD detectors or light multiplier detectors. Additionally, the optical system 200, 210 may include a set of optical elements (e.g., illumination optics, light-collecting systems, beam splitters 206, filters, and the like) configured to guide (and focus) illumination from the light source 202 onto the surface of the substrate, and in turn guide illumination from the surface of the substrate to the imaging portion of the detector 204 of the optical system 200, 210. For example, the set of optical elements of optical systems 200, 210 may include, but is not limited to, a main imaging lens adapted to image an illuminated area of ​​the substrate onto one or more light-collecting portions of detector 204. Furthermore, imaging detector 204 may be communicatively coupled to an image processing computer capable of recognizing and storing image data acquired from detector 204.

[0037] The optical systems 200 and 210 disclosed herein can be configured as any optical system known in the art, including (but not limited to) inspection systems, measurement systems, and lithography systems. For example, such as Figure 6AAs shown, the optical system 200 can be configured as a bright-field (BF) inspection system. Alternatively, such as Figure 6B As shown, optical system 210 can be configured as a dark-field (DF) inspection system. It should be noted that... Figure 6A and 6B The optical configurations depicted are for illustrative purposes only and should not be construed as limiting. Generally, optical systems 200 and 210 may include any group of imaging and optical elements suitable for imaging the surface of a substrate.

[0038] The embodiments disclosed herein provide a more compact lift assembly 10 compared to other lifting devices. Therefore, the lift assembly 10 can be adapted to a smaller overall space and can be configured for use in different optical systems. Furthermore, wear on the lift assembly components is reduced due to frictionless actuation provided by the guide tube structure 22, as this actuation adapts to tilting, cylinder rotation, and uneven loads.

[0039] Although the invention has been described in detail with reference to only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Specifically, the invention can be modified to incorporate various variations, alterations, substitutions, or equivalent arrangements not previously described but commensurate with the spirit and scope of the invention. Furthermore, although various embodiments of the invention have been described, it should be understood that aspects of the invention may include only some of the described embodiments. Moreover, any feature, element, component, or advantage of any embodiment may be used in any of the other embodiments. Therefore, the invention is not to be considered limited to the foregoing description.

Claims

1. A lifter assembly for an optical system, the lifter assembly comprising: A chuck, comprising a chuck base and a removable top plate, wherein the removable top plate is one of a plurality of replaceable removable top plates configured to support a substrate. A movable plate supports the chuck on its upper surface, and the movable plate can be vertically adjusted between a lower retracted position and an upper extended position. A conduit structure, which is operatively coupled to the movable plate; A plurality of guide shafts extending through holes in the movable plate to guide vertical adjustment of the movable plate, the plurality of guide shafts being located outside the guide tube structure; and A pneumatic system, fluidly coupled to the guide tube structure for selective expansion and contraction, wherein expansion of the guide tube structure vertically adjusts the movable plate to the upper extended position and contraction of the guide tube structure vertically adjusts the movable plate to the lower retracted position.

2. The lifting assembly of claim 1, wherein the pneumatic system includes a solenoid having an inlet port, an outlet port and a discharge port, the inlet port being fluidly coupled to a compressed air source to selectively supply compressed air through the outlet port to the internal chamber of the guide tube structure to expand the guide tube structure, and the discharge port being fluidly coupled to a vacuum generating device to extract compressed air from the internal chamber of the guide tube structure to contract the guide tube structure.

3. The lifting assembly according to claim 1, further comprising: Top cover; Base flange; and Each of the plurality of guide shafts extends through a hole in the movable plate to guide vertical adjustment of the movable plate, and each of the guide shafts is operatively coupled to the top cover and the base flange.

4. The lifting assembly according to claim 3, further comprising a stop protruding upward from the upper surface of the movable plate.

5. The lifting assembly of claim 4, further comprising an upper travel limiting feature integrally formed with the top cover, wherein contact between the upper travel limiting feature and the stop operatively defines the upper extension position of the movable plate.

6. The lifting assembly of claim 4, further comprising an upper travel limiting feature operatively coupled to the top cover, wherein contact between the upper travel limiting feature and the stop operatively defines the upper extension position of the movable plate.

7. The lifting assembly of claim 3, further comprising an upper flange having a main portion disposed between the top surface of the guide tube structure and the lower surface of the movable plate, the upper flange also having a downwardly projecting portion positioned to contact an upwardly projecting portion of the base flange to define the lower retracted position of the movable plate.

8. The lifter assembly of claim 1, further comprising a plurality of bushing housings corresponding to a number of the plurality of guide shafts, each of the bushing housings being coupled to the movable plate and having a bushing disposed therein, Each bushing concentrically surrounds the corresponding one of the plurality of guide shafts.

9. The lifting device assembly according to claim 1, wherein the guide tube structure is a welded guide tube structure.

10. The elevator assembly of claim 1, wherein the substrate comprises a semiconductor wafer.

11. An optical system comprising: Substrate chuck system, which has: A chuck having a chuck base and a removable top plate configured to support a substrate; A movable plate supports the chuck on its upper surface, and the movable plate can be vertically adjusted between a lower retracted position and an upper extended position. A guide tube structure operatively coupled to the movable plate, wherein expansion of the guide tube structure vertically adjusts the movable plate to the upper extended position and contraction of the guide tube structure vertically adjusts the movable plate to the lower retracted position; and Multiple guide shafts extend through holes in the movable plate to guide vertical adjustment of the movable plate, the multiple guide shafts being located outside the guide tube structure; An illumination source configured to illuminate one or more portions of the substrate; and A detector configured to collect illumination from one or more irradiated portions of the substrate.

12. The optical system of claim 11, wherein the optical system is configured as an inspection tool.

13. The optical system of claim 11, wherein the optical system is configured as a measuring tool.

14. The optical system of claim 11, further comprising a pneumatic system fluidly coupled to the guide tube structure for selective expansion and contraction, wherein expansion of the guide tube structure vertically adjusts the movable plate to the upper extended position and contraction of the guide tube structure vertically adjusts the movable plate to the lower retracted position.

15. The optical system of claim 14, wherein the pneumatic system comprises a solenoid having an inlet port, an outlet port, and a discharge port, the inlet port being fluidly coupled to a compressed air source to selectively supply compressed air through the outlet port to an internal chamber of the guide tube structure to expand the guide tube structure, and the discharge port being fluidly coupled to a vacuum generating device to extract compressed air from the internal chamber of the guide tube structure to contract the guide tube structure.

16. The optical system of claim 11, further comprising: Top cover; Base flange; and Each of the plurality of guide shafts extends through a hole in the movable plate to guide vertical adjustment of the movable plate, and each of the guide shafts is operatively coupled to the top cover and the base flange.

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