Lifter assembly with guide tube for optical inspection system

Abstract

A lifter assembly for an optical system includes a chuck having a chuck base and a removable top plate, where the removable top plate is one of a plurality of replaceable removable top plates configured to support a substrate. The lifter assembly also includes a movable plate to support the chuck on an upper surface of the movable plate, the movable plate being vertically adjustable between a lower retracted position and an upper extended position. The lifter assembly further includes a guide tube structure operatively coupled to the movable plate. The lifter assembly yet further includes a pneumatic system fluidly coupled to the guide tube structure to selectively expand and contract, where expansion of the guide tube structure vertically adjusts the movable plate to the upper extended position, and the movable plate is vertically adjusted to the lower retraction position through retraction of the guide opening pipe structure.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

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

[0003]

[0013] Embodiments described herein relate to optical inspection systems, and more particularly, to a pneumatic lifter assembly for use in such systems. Background Art

[0004] Inspection processes are used at various steps during the semiconductor manufacturing process to detect defects on the wafer to facilitate an improved yield in the manufacturing process, thereby achieving higher profits. Inspection has always been an important part of manufacturing semiconductor devices. However, as the size of semiconductor devices decreases, inspection becomes more important to the successful manufacture of acceptable semiconductor devices because smaller defects can cause device failure.

[0005] Some manufacturing, metrology and defect inspection processes require vertical movement of a chuck with a substrate positioned on its top surface. The lifter assembly supports the chuck and actuates the vertical movement. For example, a pneumatic rod may be located in a chamber of the lifter assembly and connected to a support feature and a movable plate to implement vertical movement of the chuck by introducing and removing fluids. Some tools that work with the lifter assembly may provide limited space to accommodate all lifter assembly features during operation. The aforementioned pneumatic rods take up more space when the lifter assembly extends away from the retracted (i.e., downward) position to the upward position. In addition, the pneumatic rod cannot maintain the verticality of the support feature adjacent to it when lifting or applying an uneven load, thereby causing wear in the hole in which the rod slides. Finally, the pneumatic rod can only be extended to a fixed stroke length that cannot be adjusted.

[0006] The above problems 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 also includes a movable plate to support the chuck on an upper surface of the movable plate, the movable plate being vertically adjustable between a lower retracted position and an upper extended position. The lifter assembly further includes a nozzle tube structure operatively coupled to the movable plate. The lifter assembly further includes a pneumatic system fluidly coupled to the nozzle tube structure for selective expansion and contraction, wherein expansion of the nozzle tube structure vertically adjusts the movable plate to the upper extended position and contraction of the nozzle tube structure vertically adjusts the movable plate to the lower retracted position.

[0008] According to another aspect of the invention, an optical system includes a substrate chuck subsystem having a chuck having a chuck base and a removable top plate, the removable top plate being configured to support a substrate. The optical system also includes a movable plate to support the chuck on an upper surface of the movable plate, the movable plate being vertically adjustable between a lower retracted position and an upper extended position. The optical system further includes a nozzle tube structure operatively coupled to the movable plate, wherein expansion of the nozzle tube structure vertically adjusts the movable plate to the upper extended position and contraction of the nozzle tube structure vertically adjusts the movable plate to the lower retracted position. The optical system still 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 one or more portions of the substrate.

[0009] According to yet another aspect of the present invention, a lifter assembly for vertically repositioning a substrate includes a vacuum chuck configured to support the substrate and hold the substrate with vacuum gas pressure. The lifter assembly also 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 lower retracted position and an upper extended position. The lifter assembly further includes a welded nozzle tube structure operatively coupled to the movable plate, wherein expansion of the welded nozzle tube structure vertically adjusts the movable plate to the upper extended position and contraction of the nozzle tube structure vertically adjusts the movable plate to the lower retracted position.

[0010] These aspects and other advantages and features will become apparent from the following description taken in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] The objects which are regarded as embodiments of the present invention are particularly pointed out and distinctly claimed in the claims at the end of this specification. Features and advantages of the disclosed embodiments are apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0012] Figure 1 is a partial cross-sectional elevation view of an optical inspection system lifter assembly supporting a chuck;

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

[0014] Figure 3A illustrating the riser assembly and its connected fluid lines in a retracted position;

[0015] Figure 3B illustrating the riser assembly and its connected fluid lines in an extended position;

[0016] Figure 4A illustrating the riser assembly in a retracted position;

[0017] Figure 4B illustrating the riser assembly in an extended position;

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

[0019] Fig. 6A schematically illustrates an optical system incorporating an embodiment of a lifter assembly disclosed herein according to one aspect of the present invention; and

[0020] Figure 6B An optical system incorporating an embodiment of a lifter assembly disclosed herein according to another aspect of the invention is schematically illustrated. DETAILED DESCRIPTION

[0021] With reference to the drawings, while the present invention will be 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 drawings are not necessarily drawn to scale, as some features may be exaggerated, reduced, or simplified to show details of particular components. Therefore, the specific structural and functional details disclosed herein and illustrated in the drawings should not be interpreted as limiting, but merely as a representative basis for teaching those skilled in the art to variously employ the present invention.

[0022] refer to Figure 1, a portion of a substrate chuck system for an optical system is shown and generally referred to by reference numeral 11. An embodiment of a lifter assembly 10 is disclosed herein as supporting and vertically adjusting a chuck 14. The lifter assembly 10 includes a movable plate 12 that supports the chuck 14. The chuck 14 is configured to support a substrate, such as, for example, a semiconductor wafer (not shown). Various types of contemplated chucks may be used with the lifter assembly 10 disclosed herein. By way of non-limiting example, the lifter assembly 10 may be used with a 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 a substrate in position on a 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 unitary 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 to be quickly replaced 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, overall tool / stage, and optical system, the embodiments of the lifter assembly 10 disclosed herein include a port tube structure 22 that actuates substantially vertical movement of the movable plate 12 and, therefore, the chuck 14 and the substrate supported thereon. In some embodiments, the port tube structure 22 is a welded port tube type. The port tube structure 22 is formed as a folded structure such that a plurality of annular port tube plates having radially curved surfaces are connected on the outer diameter side and the inner diameter side in an alternating manner. The port tube plates are connected together by TIG welding or the like in, for example, an atmospheric or Ar gas environment. The port tube structure 22 defines a hollow interior chamber.

[0025] 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 metrology device, an inspection device, or a combination of metrology and inspection devices. Vertical adjustment of the movable plate 12, chuck 14, and substrate facilitates various actions of the optical system.

[0026] Reference Figure 2, the lifter assembly 10 is shown in detail. As shown, in the illustrated embodiment, the fastener and guide 20 are radially outside the vacuum inlet 15, which is in accordance with Figure 1 Thus, it should be understood that either configuration is contemplated.

[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 of 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 shaft 32 may be coupled to the base flange 28 and the top cover 30 by 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 shaft 32 guides the vertical movement to maintain the adjustment in the vertical direction. The number of the plurality of guide shafts 32 may vary depending on the specific use application.

[0028] 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 between at least one of the plurality of arms 26 of the movable plate 12 via a first conduit arrangement 42. The first fluid connection provides the vacuum air pressure required to hold the substrate on the chuck 14, as described above. A second fluid connection is formed between the interior chamber of the orifice tube structure 22 and a selectively switchable supply from a compressed air source 44 and a vacuum air pressure source 46 via a second conduit arrangement 48. 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 the compressed air to the interior chamber of the orifice tube structure 22; and an exhaust port 56 for drawing compressed air from the interior chamber of the orifice tube structure 22 through the vacuum air pressure source 46.

[0029] In the illustrated embodiment, the opening solenoid 50 is a 3-way solenoid, but it should be understood that other types of plumbing arrangements may be used for the second fluid connection to selectively route compressed air into and out of the interior chamber of the port tube structure 22. In the illustrated embodiment of the opening solenoid 50, when the opening solenoid 50 is de-energized, vacuum pressure is provided to the port tube structure 22 to contract the port tube structure 22, thereby lowering the movable plate 12. Conversely, after the opening solenoid 50 is energized, compressed air enters the port tube structure 22 through the pressure regulator 58 preset to a pressure value sufficient to expand the port tube structure 22, thereby lifting the moving mass including the movable plate 12, the chuck 14, and the substrate supported thereon.

[0030] refer to Figure 4A and 4B , the lifter 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 upper extension position ( Figure 4B ) to vertically adjust the movable plate 12, the chuck 14 and the substrate. As described above, a plurality of guide shafts 32 extend through corresponding holes of 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. In particular, the movable plate 12 has a plurality of bushing arrangements 60 mounted on its upper surface 62, which corresponds to the number of guide shafts 32. Therefore, each guide shaft 32 passes through a corresponding bushing arrangement 60. Each bushing arrangement 60 includes a bushing housing 64 containing a bushing 68 therein. The bushing arrangement 60 concentrically surrounds a portion of the guide shaft 32 and translates with the movable plate 12.

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

[0032] The upper extended position is defined by contact between the upper travel limiting feature 70 and an upper stop 72 that 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 a lower surface 74 of the top cover 30. In other embodiments, the upper travel limiting feature 70 is a separate component from the top cover 30 and is operatively coupled to the top cover 30, as illustrated. For example, the upper travel limiting feature 70 may be screwed directly to the top cover 30 or coupled to the top cover 30 by mechanical fasteners. The upper travel limiting feature 70 is positioned to be contacted by an upper stop 72 that extends upwardly 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 segment 76 that extends through the movable plate 12 to be threaded to the movable plate 12 or may extend completely through the movable plate 12 to couple to an upper flange 78 disposed below the movable plate 12. Any of the embodiments disclosed herein result 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 contact between the lower travel limiting feature 80 and a lower stop 82 that 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 protruding portion, which in the illustrated embodiment is the lower stop 82. The lower stop 82 is positioned to contact an upwardly protruding 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 can be a component that is operatively coupled to the base flange 28 rather than integrally formed therewith. Similarly, in other embodiments, the lower stop 82 can be operatively coupled to the upper flange 78 or the movable plate 12.

[0034] Reference Figure 5 , the slider assembly 90 is provided as Figure 4A and 4B. The slider assembly 90 includes a plurality of slide rails 92 extending through respective 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 a 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 by nuts 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 the vertical movement to maintain the adjustment in the vertical direction. The number of the plurality of slide rails 92 may vary depending on the specific use application.

[0035] A plurality of mounting plates 94 corresponding to the number of the plurality 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 the vertical movement of the movable plate 12, the slider assembly 90 ensures smooth guided movement of the movable plate 12.

[0036] Reference Fig. 6A and 6B , illustrating a simplified schematic diagram of an optical system 200, 210 equipped with the lifter 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 an area on the surface of the substrate. In another embodiment, the optical system 200, 210 includes one or more detectors 204 or cameras suitable for detecting light reflected, diffracted, or scattered from the area 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 photomultiplier detectors. Additionally, the optical system 200, 210 may include a set of optical elements (e.g., illumination optics, light collection systems, beam splitters 206, filters, and the like) configured to direct (and focus) illumination from the light source 202 onto the surface of the substrate, and in turn direct illumination from the surface of the substrate to an 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 are not limited to, a primary imaging lens adapted to image an illuminated region of a substrate onto light collecting portion(s) of detector 204. Furthermore, imaging detector 204 may be communicatively coupled to an image processing computer that may recognize and store image data acquired from detector 204.

[0037] The optical systems 200, 210 disclosed herein may be configured as any optical system known in the art, including but not limited to inspection systems, metrology systems, and lithography systems. Fig. 6AAs shown in FIG. 2 , the optical system 200 may be configured as a bright field (BF) inspection system. Figure 6B As shown in FIG. , the optical system 210 can be configured as a dark field (DF) inspection system. It should be noted that Fig. 6A and 6B The optical configurations depicted in are for illustration only and should not be construed as limiting. In general, the optical systems 200, 210 may include any set of imaging and optical elements suitable for imaging a surface of a substrate.

[0038] The embodiments disclosed herein provide a lifter assembly 10 that is more compact relative to other lift devices. Thus, the lifter assembly 10 can fit into a smaller overall space and can be configured for use in different optical systems. Additionally, wear on lifter assembly components is reduced due to the frictionless actuation provided by the port tube structure 22 because this actuation accommodates tilt, cylinder rod rotation, and uneven loads.

[0039] Although the present invention is described in detail only in conjunction with a limited number of embodiments, it should be readily understood that the present invention is not limited to such disclosed embodiments. Specifically, the present invention may be modified to incorporate various variations, changes, substitutions, or equivalent arrangements that have not been described heretofore but are commensurate with the spirit and scope of the present invention. In addition, although various embodiments of the present invention have been described, it should be understood that aspects of the present invention may include only some of the described embodiments. In addition, any features, elements, components, or advantages of any one embodiment may be used on any one of the other embodiments. Therefore, the present invention is not considered to be 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 supporting the chuck on an upper surface of the movable plate, the movable plate being vertically adjustable between a lower retracted position and an upper extended position; a port structure operatively coupled to the movable plate; and A pneumatic system is fluidly coupled to the port tube structure for selective expansion and contraction, wherein expansion of the port tube structure vertically adjusts the movable plate to the upper extended position and contraction of the port tube structure vertically adjusts the movable plate to the lower retracted position.

2. A lifter assembly according to claim 1, wherein the pneumatic system includes a solenoid having an inlet port, an outlet port and an exhaust port, the inlet port being fluidically coupled to a compressed air source to selectively provide compressed air into an internal chamber of the orifice tube structure through the outlet port to expand the orifice tube structure, and the exhaust port being fluidically coupled to a vacuum generating device to draw compressed air from the internal chamber of the orifice tube structure to contract the orifice tube structure.

3. The lifter assembly of claim 1, further comprising: Top cover; Base flange; and A plurality of guide shafts extend through the holes of the movable plate to guide vertical adjustment of the movable plate, each of the guide shafts being operatively coupled to the top cover and the base flange. 4 . The lifter assembly of claim 3 , further comprising a stopper protruding upward from the upper surface of the movable plate.

5. The riser 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 extended position of the movable plate.

6. The riser 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 extended position of the movable plate.

7. The lifter assembly according to claim 3 further includes an upper flange having a main body 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 downward protruding portion, the downward protruding portion being positioned to contact the upward protruding portion of the base flange to define the lower retracted position of the movable plate.

8. The lifter assembly according to claim 3, further comprising a plurality of bushing housings corresponding to the 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 a corresponding one of the plurality of guide shafts.

9. The lifter assembly of claim 1, further comprising: Top cover; Base flange; a plurality of slide rails extending through the apertures of the movable plate to guide vertical adjustment of the movable plate, each of the slide rails being operatively coupled to the top cover and the base flange; and A plurality of mounting plates corresponding to the number of the plurality of slide rails, each of the mounting plates being coupled to the movable plate and having a sliding member disposed between the corresponding mounting plate and the corresponding slide rail.

10. The riser assembly of claim 1, wherein the port tube structure is a welded port tube structure.

11. The lifter assembly of claim 1, wherein the substrate comprises a semiconductor wafer.

12. An optical system comprising: A substrate chuck subsystem having: a chuck having a chuck base and a removable top plate configured to support a substrate; a movable plate supporting the chuck on an upper surface of the movable plate, the movable plate being vertically adjustable between a lower retracted position and an upper extended position; and 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; an illumination source configured to illuminate one or more portions of the substrate; and A detector is configured to collect illumination from the illuminated one or more portions of the substrate.

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

14. The optical system of claim 12, wherein the optical system is configured as a metrology tool.

15. The optical system of claim 12, further comprising a pneumatic system coupled to the nozzle tube structure via a fluid for selective expansion and contraction, wherein expansion of the nozzle tube structure vertically adjusts the movable plate to the upper extended position and contraction of the nozzle tube structure vertically adjusts the movable plate to the lower retracted position.

16. An optical system according to claim 15, wherein the pneumatic system includes a solenoid having an inlet port, an outlet port and an exhaust port, the inlet port being fluidically coupled to a compressed air source to selectively provide compressed air into an internal chamber of the orifice-tube structure through the outlet port to expand the orifice-tube structure, and the exhaust port being fluidically coupled to a vacuum generating device to draw compressed air from the internal chamber of the orifice-tube structure to contract the orifice-tube structure.

17. The optical system of claim 12, further comprising: Top cover; Base flange; and A plurality of guide shafts extend through the holes of the movable plate to guide vertical adjustment of the movable plate, each of the guide shafts being operatively coupled to the top cover and the base flange.

18. The optical system of claim 12, further comprising: Top cover; Base flange; a plurality of slide rails extending through the apertures of the movable plate to guide vertical adjustment of the movable plate, each of the slide rails being operatively coupled to the top cover and the base flange; and A plurality of mounting plates corresponding to the number of the plurality of slide rails, each of the mounting plates being coupled to the movable plate and having a sliding member disposed between the corresponding mounting plate and the corresponding slide rail.

19. A lifter assembly for vertically repositioning a substrate, the lifter assembly comprising: a vacuum chuck configured to support the substrate and hold the substrate with vacuum air pressure; a movable plate supporting the vacuum chuck on an upper surface of the movable plate, the movable plate being vertically adjustable between a lower retracted position and an upper extended position; and A welded port tube structure is operatively coupled to the movable plate, wherein expansion of the welded port tube structure vertically adjusts the movable plate to the upper extended position and contraction of the port tube structure vertically adjusts the movable plate to the lower retracted position.

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