Wafer rotation positioning stage

Abstract

The application provides a wafer rotating positioning platform, belonging to the technical field of semiconductor driving, which comprises a supporting module, a rotating driving module and a plurality of gravity balance modules arranged on the bottom surface of the supporting disc, the rotating driving module drives the supporting module to rotate around the axis, and the rotating angle is positioned and controlled through air floating and magnetic attraction; the wafer rotating positioning platform is accurately controllable in rotation, and adopts air floating, magnetic force position locking and gravity balance, so that the driving control is more precise, and the wafer rotating positioning platform is convenient to popularize and apply in the fields of semiconductor overlay alignment, measurement detection, manufacturing and high-end precision instrument driving.

Description

Technical Field

[0001] This invention belongs to semiconductor driving technology, specifically relating to a wafer rotation positioning stage. Background Technology

[0002] In semiconductor wafer inspection and processing equipment, wafers typically need to be supported and positioned by a stage. However, existing stages generally require rotation around the Z-axis, but motion introduces inertia. This inertia, unwanted rotation, or ineffective rotation can all affect the stage's driving accuracy, inevitably impacting subsequent process flows. Therefore, to improve the rotation or angle adjustment accuracy of wafer support, a wafer stage capable of precisely controlling the timing of rotation is needed. This would allow for high-precision wafer positioning and support suitable for overlay, defect, CD (critical dimension) quantity inspection, and other processing scenarios. Summary of the Invention

[0003] In order to overcome the shortcomings of the prior art, the purpose of this invention is to provide a wafer rotation positioning stage that can solve the above-mentioned problems.

[0004] A wafer rotation positioning stage includes a support module and a rotation drive module. The rotation drive module drives the support module to rotate around an axis, and the rotation angle is controlled by air levitation and magnetic attraction.

[0005] Furthermore, the support module includes a support plate with a central opening and an upper leaf spring. The rotation drive module is located at the central opening of the support plate and is rotated and positioned by the engagement and disengagement of the upper leaf spring with the support plate.

[0006] Furthermore, the rotary drive module includes an air float shaft assembly, two sets of arc-shaped voice coil motors, an air float head, and a rotary positioning magnet; the air float shaft assembly includes an air float guide shaft and an air float, the air float guide shaft is non-contactly embedded in the air float cavity of the air float, the air float guide shaft is connected to the support plate, and the top of the air float is connected to the bottom surface of the upper leaf spring; the two sets of arc-shaped voice coil motors are arranged between the air float and the support plate, thereby driving the support plate to rotate relative to the axis of the air float; multiple sets of air float heads and rotary positioning magnets are evenly distributed on the outer periphery of the upper leaf spring, and the engagement and disengagement of the upper leaf spring and the support plate are realized by opening and closing the air supply.

[0007] Furthermore, the wafer rotation positioning stage also includes multiple gravity balance modules arranged on the bottom surface of the support disk. The gravity balance module includes a magnetic spring transition sleeve, a magnetic spring mover, and a magnetic spring stator. The top of the magnetic spring transition sleeve is connected to the bottom surface of the support disk, the bottom of the magnetic spring mover is connected to the lower part of the magnetic spring transition sleeve, the lower part of the magnetic spring mover is non-contactly embedded in the receiving cavity of the magnetic spring stator, and the bottom of the magnetic spring stator is fixed to ---.

[0008] Furthermore, the wafer rotation positioning stage also includes a stage base, which includes a stage body. On the upper surface of the stage body, there are countersunk holes for mounting the rotation module and countersunk holes for mounting the gravity balance module. The countersunk holes for mounting the rotation module are used to accommodate the bottom of the rotation drive module, and the countersunk holes for mounting the bottom of the gravity balance module are used to mount the bottom of the gravity balance module.

[0009] Furthermore, the wafer rotation positioning stage also includes a wafer carrier disk disposed above the support module. The wafer carrier disk includes a carrier disk body, and multiple carrier disk adsorption lugs are radially extended on the outer periphery of the carrier disk body. Wafer suction blocks are disposed on the carrier disk adsorption lugs, and two wafer fork slots are formed on the upper surface of the carrier disk body.

[0010] Compared with the prior art, the beneficial effects of the present invention are as follows: the wafer rotation positioning stage of the present application has precise and controllable rotation, and adopts air-floating magnetic position locking and gravity balance, which makes the drive and control more precise and facilitates its application in the fields of semiconductor overlay alignment, measurement, manufacturing and high-end precision instrument drive. Attached Figure Description

[0011] Figure 1 This is a schematic diagram of the wafer rotation positioning stage of the present invention; Figure 2 This is a schematic diagram of the platform. Figure 3 A schematic diagram of an example wafer rotation positioning stage; Figure 4 for Figure 3 A sectional view; Figure 5 for Figure 3 Exploded view; Figure 6 This is a schematic diagram of the installation of an arc-shaped voice coil motor; Figure 7 This is a schematic diagram of a wafer transfer device.

[0012] In the picture: 10. Platform; 11. Platform body; 12. Countersunk hole for rotating module mounting; 13. Countersunk hole for gravity balance module mounting; 20. Support module; 21. Support plate; 22. Upper leaf spring; 23. Lower leaf spring; 231. Leaf spring groove; 232. Torque absorption hole; 233. Leaf spring pressure block assembly; 30. Lifting and leveling module; 40. Rotary drive module; 41. Air float cylinder shaft assembly; 42. Arc-shaped voice coil motor; 421. Motor yoke; 422. Motor magnet; 423. Motor coil; 424. Coil frame; 43. Air float head; 44. Rotary positioning magnet; 411. Air float guide shaft; 4111. Guide shaft connecting lug; 412. Air float cylinder; 4121. Float lug; 45. Air float fixing adapter top plate; 46. Porous graphite air ring; 47. Retaining ring pressure head; 48. Rotary grating assembly; 49. Rotary limit assembly; 50. Gravity balance module; 51. Magnetic spring transition sleeve; 52. Magnetic spring mover; 53. Magnetic spring stator; 60. Wafer carrier; 61. Carrier body; 62. Carrier suction lug; 63. Wafer suction block; 64. Wafer fork slot; 100. Vibration damping platform; 200, Y-axis first drive module; 300, Y-axis second drive module; 400, X-axis drive module; 500. Wafer adsorption stage. Detailed Implementation

[0013] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0014] A wafer rotation positioning stage, see Figures 1-6 It includes a support module 20 and a rotary drive module 40. The rotary drive module 40 drives the support module 20 to rotate around the axis, and the rotation angle is positioned and controlled by air buoyancy and magnetic attraction.

[0015] The support module 20 includes a support plate 21 with a central opening and an upper leaf spring 22. The rotation drive module 40 is located at the central opening of the support plate 21 and is rotated and positioned by the engagement and disengagement of the upper leaf spring 22 with the support plate 21. The upper leaf spring 22 is a triangular shape with curved edges.

[0016] The rotary drive module 40 includes an air float shaft assembly 41, two sets of arc-shaped voice coil motors 42, an air float head 43, and a rotary positioning magnet 44.

[0017] Specifically, the air flotation cylinder shaft assembly 41 includes an air flotation guide shaft 411 and an air flotation cylinder 412. The air flotation guide shaft 411 is non-contactly embedded in the air flotation cavity of the air flotation cylinder 412. The air flotation guide shaft 411 is connected to the support plate 21, and the top of the air flotation cylinder 412 is connected to the bottom surface of the upper leaf spring 22.

[0018] Two sets of arc-shaped voice coil motors 42 are arranged between the air float 412 and the support plate 21, thereby driving the support plate 21 to rotate relative to the axis of the air float 412.

[0019] Multiple sets of air floats 43 and rotating positioning magnets 44 are evenly distributed around the outer periphery of the upper leaf spring 22. The upper leaf spring 22 is engaged or disengaged from the support plate 21 by blowing off the air.

[0020] The top outer periphery of the air flotation guide shaft 411 extends outward on both sides to form guide shaft connecting lugs 4111. The air flotation cylinder 412 has a limiting groove corresponding to the guide shaft connecting lugs 4111. The guide shaft connecting lugs 4111 are connected to the support plate 21.

[0021] The air float head 43 is cylindrical, with a cylindrical rotating positioning magnet 44 set in the hollow middle, and the rotating positioning magnet 44 is fixed to the air float head 43 by a magnetic screw, so that the air float head 43 has an annular blowing surface along the outer periphery of the rotating positioning magnet 44.

[0022] Two sets of arc-shaped voice coil motors 42 are arranged opposite each other on the outer periphery of the air float 412. Each set of arc-shaped voice coil motors 42 includes a motor yoke 421, a motor magnet 422, a motor coil 423, and a coil frame 424. The motor yoke 421 is mounted on the float lug 4121 provided on the outer periphery of the air float 412. The top of the coil frame 424 is connected to the support plate 21.

[0023] Furthermore, the rotary drive module 40 also includes an air-float fixed adapter plate 45, the outer periphery of the bottom surface of the air-float fixed adapter plate 45 is fixedly connected to the top surface of the support plate 21 near the central hole, the guide shaft connecting lug 4111 of the air-float guide shaft 411 is connected to the air-float fixed adapter plate 45, and the coil frame 424 of the two sets of arc voice coil motors 42 is also connected to the air-float fixed adapter plate 45.

[0024] Furthermore, the rotary drive module 40 also includes a porous graphite gas ring 46. The columnar rotary positioning magnet 44 passes through the central hole of the porous graphite gas ring 46 and is then fitted into the recessed cavity of the air float head 43. The upper leaf spring 22 is connected to the top of the air float head 43 by a retaining ring pressure head 47 screw.

[0025] The porous graphite air ring 46 blows air, which can separate the rotary positioning magnet 44 that is attracted to the upper leaf spring 22.

[0026] Furthermore, the rotary drive module 40 also includes an air-floating magnetic base plate. The locking mounting hole of the support plate 21 is a through hole. The air-floating magnetic base plate is located below the support plate 21 and blocks the locking mounting hole. The bottom of the rotary positioning magnet 44 is magnetically attracted to the air-floating magnetic base plate and is controlled by the air-floating head 43 to engage or disengage.

[0027] In this example, the support plate 21 is made of a non-magnetic material, so a ferromagnetic air-floating magnetic base plate is used. This reduces the weight of the support plate 21 and the entire platform.

[0028] The wafer rotation positioning stage also includes multiple gravity balance modules 50 arranged on the bottom surface of the support disk 21. The gravity balance module 50 includes a magnetic spring transition sleeve 51, a magnetic spring mover 52, and a magnetic spring stator 53. The top of the magnetic spring transition sleeve 51 is connected to the bottom surface of the support disk 21, the bottom of the magnetic spring mover 52 is connected to the lower part of the magnetic spring transition sleeve 51, and the lower part of the magnetic spring mover 52 is non-contactly embedded in the receiving cavity of the magnetic spring stator 53. The bottom of the magnetic spring stator 53 is fixed.

[0029] When the air-float fixed adapter plate 45 is set as the adapter, the top of the magnetic spring transition sleeve 51 is connected to the air-float fixed adapter plate 45, thereby indirectly connecting to the support plate 21.

[0030] In the illustrated example, three sets of gravity balancing modules 50 are set on the bottom surface of the support plate 21 to balance the gravity of the upper support plate 21 through electromagnetic elastic force.

[0031] The wafer rotation positioning stage also includes a stage base 10, see [link to documentation]. Figure 2 The platform 10 includes a platform body 11, on the upper surface of which a rotating module mounting countersunk hole 12 and a gravity balance module mounting countersunk hole 13 are formed; the rotating module mounting countersunk hole 12 is used to accommodate the bottom of the rotating drive module 40, and the gravity balance module mounting countersunk hole 13 is used to mount the bottom of the gravity balance module 50.

[0032] Specifically, the bottom of the air float shaft assembly 41 is not connected and is embedded in the rotating module mounting countersunk hole 12 on the top surface of the platform 10. The bottom of the magnetic spring stator 53 is connected to the gravity balance module mounting countersunk hole 13 of the platform 10.

[0033] Furthermore, the support module 20 also includes a lower leaf spring 23. The lower leaf spring 23 has a central hole and leaf spring grooves 231 formed in the radial direction to form equally divided leaf plate areas. The inner end of the leaf spring groove 231 is connected to the central hole of the leaf spring, and the outer end of the leaf spring groove 231 is connected to a torque absorption hole 232. The middle ends of multiple leaf plate areas are alternately connected to the upper surface of the support plate 21 and the upper surface of the middle part of the platform 10 through the leaf spring pressure block assembly 233.

[0034] Furthermore, the rotary drive module 40 also includes a rotary grating assembly 48 and a rotary limiting assembly 49. The rotary grating assembly 48 is disposed on a support plate 21 on the outer side of one air float 43, and the rotary limiting assembly 49 is disposed on the support plates 21 on the outer side of the remaining air floats 43.

[0035] Furthermore, in order to diversify the functions of this wafer rotation positioning stage and meet the needs of multiple application scenarios, a lifting and leveling module 30 with lifting and leveling functions can be added. The lifting and leveling module 30 includes a lifting voice coil motor, a lifting grating ruler assembly, a lifting subdivision box, and a lifting limit assembly.

[0036] The bottoms of multiple lifting voice coil motors are connected to the corresponding lifting module mounting holes of the platform 10, and the tops of the lifting voice coil motors are connected to the support plate; the lifting grating ruler assembly is connected to the support plate 21 through the grating frame; the lifting grating ruler assembly is electrically connected to the lifting subdivision box; the lifting limit assembly is connected to the platform 10 and the support plate 21, and monitors the Z-axis position and limit of the lifting voice coil motor through mechanical and photoelectric dual modes.

[0037] The lifting and leveling module 30 is set in three groups, with three corresponding lifting mounting holes on the support plate 21. The top of the lifting voice coil motor and the top of the grating frame of the lifting grating ruler assembly are connected to the Z-axis mounting plate above through the lifting mounting holes.

[0038] The lifting subdivision box is mounted on the platform 10 via a box frame and is electrically connected to the lifting reading head of the lifting grating ruler assembly, thereby achieving subdivision of the lifting position and improving the detection accuracy.

[0039] The lifting limit assembly includes mechanical limit components and photoelectric limit components, which are disposed on the outer periphery of the support plate 21.

[0040] Among them, see Figure 1 The wafer carrier 60 includes a carrier body 61, and a plurality of carrier adsorption lugs 62 are radially extended on the outer periphery of the carrier body 61. Wafer suction blocks 63 are provided on the carrier adsorption lugs 62, and two wafer fork slots 64 are formed on the upper surface of the carrier body 61.

[0041] A wafer transfer device, see Figure 7The system includes a Y-axis first drive module 200 and a Y-axis second drive module 300 mounted on a vibration damping platform 100. An X-axis drive module 400 is supported at both ends by corresponding Y-axis drive modules. A wafer adsorption stage 500, using the aforementioned wafer rotation positioning platform, is mounted on the X-axis drive module 400. The Y-axis first drive module 200 and the Y-axis second drive module 300 are independently driven and can be calibrated in real-time and periodically to eliminate residuals caused by the non-orthogonality between the X-axis drive module 400 and the two Y-axis drive modules. The X-axis drive module 400 adopts a U-shaped structure with one-sided drive and three-sided air-bearing guidance, providing better guidance stability and driving accuracy.

[0042] The Y-axis first drive module 200 and the Y-axis second drive module 300 are independently driven and can be calibrated in real time and periodically to eliminate the residuals caused by the non-orthogonality between the X-axis drive module 400 and the two Y-axis drive modules. The residual correction principle is as follows: the image acquisition module performs line scan image acquisition of the wafer on the wafer transfer device; the position processing module acquires the position of the wafer transfer device in all directions in real time; the residual correction calculation module compares the actual wafer image acquired by the image acquisition module with the standard wafer position image and calculates the non-orthogonal residuals; and the main control analysis module controls the independent longitudinal movement of the Y-axis first drive module 200 and the Y-axis second drive module 300 of the wafer transfer device to achieve residual correction.

[0043] The wafer adsorption stage 500 is set on the X-axis slide plate of the X-axis drive module 400 and integrates lifting, rotation around the Z-axis and XY plane leveling functions.

[0044] The vibration damping platform 100 and the longitudinal beams of the Y-axis drive module are made of marble or granite, ensuring stability and preventing deformation. The X-axis crossbeam of the X-axis drive module 400 and the wafer carrier 60 are made of silicon carbide, which is lightweight and stable. The air flotation assembly uses an air flotation pad.

[0045] This solution has been used in wafer nanoscale overlay inspection systems and wafer quantity inspection systems with and without images (including bright field and dark field). In the future, it will be extended to processing scenarios such as photolithography, PCB, and IC substrate.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A wafer rotation positioning stage, comprising a support module (20) and a rotation drive module (40), characterized in that: The rotary drive module (40) drives the support module (20) to rotate around the axis, and the rotation angle is positioned and controlled by air buoyancy and magnetic attraction. The support module (20) includes a support plate (21) with a central opening and an upper leaf spring (22). The rotation drive module (40) is located at the central opening of the support plate (21) and is rotated and positioned by the engagement and disengagement of the upper leaf spring (22) and the support plate (21). The rotary drive module (40) includes an air float shaft assembly (41), two sets of arc voice coil motors (42), an air float head (43), and a rotary positioning magnet (44). The air flotation cylinder shaft assembly (41) includes an air flotation guide shaft (411) and an air flotation cylinder (412). The air flotation guide shaft (411) is non-contactly embedded in the air flotation cavity of the air flotation cylinder (412). The air flotation guide shaft (411) is connected to the support plate (21). The top of the air flotation cylinder (412) is connected to the bottom surface of the upper leaf spring (22). Two sets of arc-shaped voice coil motors (42) are arranged between the air float (412) and the support plate (21), thereby driving the support plate (21) to rotate relative to the axis of the air float (412); Multiple sets of air floats (43) and rotating positioning magnets (44) are evenly distributed on the outer periphery of the upper leaf spring (22), and the upper leaf spring (22) and the support plate (21) are engaged and disengaged by opening and closing the air supply.

2. The wafer rotation positioning stage according to claim 1, characterized in that: Two sets of arc-shaped voice coil motors (42) are arranged opposite each other on the outer periphery of the air float (412). Each set of arc-shaped voice coil motors (42) includes a motor yoke (421), a motor magnet (422), a motor coil (423), and a coil frame (424). The motor yoke (421) is installed on the float lug (4121) provided on the outer periphery of the air float (412). The top of the coil frame (424) is connected to the support plate (21).

3. The wafer rotation positioning stage according to claim 1, characterized in that: The rotary drive module (40) also includes a porous graphite gas ring (46). A columnar rotary positioning magnet (44) passes through the central hole of the porous graphite gas ring (46) and is then fitted into the recessed cavity of the air float head (43). The upper leaf spring (22) is connected to the top of the air float head (43) by a retaining ring pressure head (47) screw.

4. The wafer rotation positioning stage according to claim 1, characterized in that: The wafer rotation positioning stage also includes multiple gravity balance modules (50) arranged on the bottom surface of the support disk (21). The gravity balance module (50) includes a magnetic spring transition sleeve (51), a magnetic spring mover (52), and a magnetic spring stator (53). The top of the magnetic spring transition sleeve (51) is connected to the bottom surface of the support disk (21), the bottom of the magnetic spring mover (52) is connected to the lower part of the magnetic spring transition sleeve (51), and the lower part of the magnetic spring mover (52) is non-contactly embedded in the receiving cavity of the magnetic spring stator (53). The bottom of the magnetic spring stator (53) is fixed.

5. The wafer rotation positioning stage according to claim 4, characterized in that: The wafer rotation positioning stage also includes a stage base (10), which includes a stage body (11). A rotating module mounting countersunk hole (12) and a gravity balance module mounting countersunk hole (13) are formed on the upper surface of the stage body (11). The rotating module mounting countersunk hole (12) is used to accommodate the bottom of the rotating drive module (40), and the gravity balance module mounting countersunk hole (13) is used to mount the bottom of the gravity balance module (50).

6. The wafer rotation positioning stage according to claim 5, characterized in that: The support module (20) also includes a lower leaf spring (23), which has a central hole and leaf spring grooves (231) formed in the radial direction to form equally divided leaf plate areas. The inner end of the leaf spring groove (231) is connected to the central hole of the leaf spring, and the outer end of the leaf spring groove (231) is connected to a torque absorption hole (232). The inner ends of multiple leaf plate areas are alternately connected to the upper surface of the support plate (21) and the upper surface of the middle part of the platform (10) through the leaf spring pressure block assembly (233).

7. The wafer rotation positioning stage according to claim 5, characterized in that: The rotary drive module (40) also includes a rotary grating assembly (48) and a rotary limiting assembly (49). The rotary grating assembly (48) is disposed on a support plate (21) on the outside of one air float (43), and the rotary limiting assembly (49) is disposed on the support plate (21) on the outside of the other air floats (43).

8. The wafer rotation positioning stage according to claim 5, characterized in that: The wafer rotation positioning stage also includes a wafer carrier (60) disposed above the support module (20). The wafer carrier (60) includes a carrier body (61), and multiple carrier adsorption lugs (62) are radially extended on the outer periphery of the carrier body (61). Wafer suction blocks (63) are disposed on the carrier adsorption lugs (62), and two wafer fork slots (64) are opened on the upper surface of the carrier body (61).

Images