KR-20260066719-A - System and method for magnetic levitation object stages

KR20260066719AKR 20260066719 AKR20260066719 AKR 20260066719AKR-20260066719-A

Abstract

The transfer system comprises a workpiece stage, two pairs of opposing linear motors, and a controller. The two pairs of opposing linear motors accelerate the workpiece stage along the longitudinal axis and maintain a vertical gap between the workpiece stage and the pairs of opposing linear motors along the vertical axis. The controller is connected to the two pairs of opposing linear motors and also controls the movement of the workpiece stage and the vertical gap. The transfer system may include reluctance actuators connected to the workpiece table, and can maintain the vertical gap and the horizontal gap between the workpiece stage and the reluctance actuators by means of a counteracting force generated by the controller. Advantageously, the transfer system can reduce contamination (which can avoid gas bearings), reduce parasitic vertical forces, reduce cogging, provide low negative stiffness, maintain precise linear control of the workpiece stage, and maintain the same gaps around the workpiece stage during high acceleration.

Inventors

럭스 스테픈
피니 네이선 로버트
카터 프레데릭 마이클

Assignees

에이에스엠엘 네델란즈 비.브이.

Dates

Publication Date: 20260512
Application Date: 20240808
Priority Date: 20230908

Claims (15)

In a transfer system, An object stage having a longitudinal axis, a transverse axis, and a vertical axis; Two pairs of opposing linear motors configured to accelerate the object stage along a longitudinal axis, configured to maintain a vertical gap along a vertical axis between the object stage and the two pairs of opposing linear motors, and the two pairs of opposing linear motors are: A first linear motor pair comprising a first upper linear motor connected to the uppermost surface of the object stage and a first lower linear motor connected to the lowermost surface of the object stage; and It includes a second linear motor pair comprising a second upper linear motor connected to the uppermost surface of the object stage and a second lower linear motor connected to the lowermost surface of the object stage, The first linear motor pair and the second linear motor pair are two opposing linear motor pairs that are symmetric about a vertical axis; and A transfer system comprising a controller connected to the two opposing linear motor pairs and configured to control the movement of the object stage along a longitudinal axis and to control the vertical gap between the object stage and the two opposing linear motor pairs along a vertical axis.
In paragraph 1, The first upper and lower linear motors are symmetric about the longitudinal axis and the second upper and lower linear motors are symmetric about the longitudinal axis; or A transfer system in which the first upper and lower linear motors are symmetric about an axis substantially parallel to the longitudinal axis, and the second upper and lower linear motors are symmetric about an axis substantially parallel to the longitudinal axis.
In paragraph 1, The first upper and lower linear motors are symmetric about the center of mass of the object stage, and the second upper and lower linear motors are symmetric about the center of mass of the object stage; or A transfer system in which the first upper and lower linear motors are symmetrical about the center of gravity of the object stage, and the second upper and lower linear motors are symmetrical about the center of gravity of the object stage.
In paragraph 1, The controller is configured to maintain a horizontal gap between the object stage and the two opposing linear motor pairs along the lateral axis; The first and second linear motor pairs extend along the longitudinal axis and are connected to the transverse distal ends of the object stage; The transverse distal ends of the above-mentioned object stage have a symmetrical shape; The above symmetrical shape includes an opening angle of approximately 90 degrees; The above symmetrical shape is a right triangle; and The above-mentioned object stage is a transfer system having a hexagonal cross-section along the transverse axis.
In paragraph 1, the controller is: To control the movement of the object stage along the longitudinal axis by the first control loop, and, A transfer system configured to control the vertical gap between the object stage and the two opposing linear motor pairs along the vertical axis using a second control loop.
In paragraph 5, The second control loop above is superimposed on the first control loop; The second control loop is applied when the variable magnets of the two opposing linear motor pairs are spatially aligned with the opposing permanent magnets of the two opposing linear motor pairs; The above second control loop is a sequence A transfer system that maintains a vertical gap, wherein a variable magnet (n is 0, 1, 2, 3, ...) is applied to the variable magnets, and thus a force along the vertical axis is applied from the variable magnets as a sequence S n .
In paragraph 5, the first and second control loops are configured to operate as a transfer system with a 3-phase control steam, 4-phase control scheme, 5-phase control scheme, 6-phase control scheme, or 9-phase control scheme.
In claim 1, the transfer system further comprises a plurality of reluctance actuators, wherein the plurality of reluctance actuators are connected to the object stage and configured to maintain a vertical gap between the object stage and the two opposing pairs of linear motors along a vertical axis; The plurality of reluctance actuators are configured to apply a counteracting force along the vertical axis against a force applied along the vertical axis by the controller; The plurality of reluctance actuators are symmetric about a vertical axis and are configured to maintain a horizontal gap between the object stage and the plurality of reluctance actuators; and A transfer system in which the plurality of reluctance actuators extend along a longitudinal axis and are connected to the transverse distal ends of the object stage.
In paragraph 8, The transverse distal ends of the above-mentioned object stage have a symmetrical shape; The above symmetrical shape includes an opening angle of approximately 90 degrees; The above symmetrical shape is a right triangle; The above-mentioned object stage has a hexagonal cross-section along the transverse axis; The transverse distal ends of the above-mentioned object stage are a transfer system comprising a soft magnetic material.
In paragraph 1, The first upper linear motor is configured to maintain a first upper vertical gap between the uppermost surface of the object stage and the first upper linear motor; The first lower linear motor is configured to maintain a first lower vertical gap between the lowest surface of the object stage and the first lower linear motor; The second upper linear motor is configured to maintain a second upper vertical gap between the uppermost surface of the object stage and the second upper linear motor; and A transfer system configured such that the second lower linear motor maintains a second lower vertical gap between the lowest surface of the object stage and the second lower linear motor.
In Clause 10, the above controller is: To adjust the first upper and lower linear motors so that the first upper and lower vertical gaps are equal, and A transfer system configured to adjust the second upper and lower linear motors so that the second upper and lower vertical gaps are equal.
In paragraph 1, The forces between the first upper and lower linear motors of the first linear motor pair are equal in magnitude and opposite in direction, and A transfer system in which the forces between the second upper and lower linear motors of the second linear motor pair are equal in magnitude and opposite in direction.
A transfer system according to claim 1, wherein the spatial arrangement of the two opposing linear motor pairs surrounding the object stage is configured to reduce parasitic vertical forces in the first and second linear motor pairs.
In linear motors, A first component comprising an armature having a plurality of magnetic cores surrounded by respective coil windings, thereby forming a plurality of variable magnets; A second component comprising a plurality of permanent magnets having alternating polarities—the first and second components are opposed and configured to translate relative to each other along the longitudinal axis of the linear motor and to maintain a vertical gap between the first component and the second component—; and A linear motor comprising a controller connected to the first component and configured to control translational movement along a longitudinal axis and to control a vertical gap between the first component and the second component.
In a lithography apparatus, A lighting system configured to illuminate a patterning device; A projection system configured to project an image of the patterning device onto a patterning substrate; A reticle stage configured to support the patterning device and comprising a longitudinal axis, a transverse axis, and a vertical axis; and It includes a transfer system configured to translate the above-mentioned reticle stage, and The above transfer system is: Two pairs of opposing linear motors configured to translate the reticle stage along a longitudinal axis, said pairs of opposing linear motors configured to maintain a vertical gap between the reticle stage and the two pairs of opposing linear motors along a vertical axis; and A lithography apparatus comprising a controller connected to the two pairs of opposing linear motors and configured to control the translational movement of the reticle stage along a longitudinal axis and to control the vertical gap between the reticle stage and the two pairs of opposing linear motors along a vertical axis.

Description

System and method for magnetic levitation object stages Cross-reference regarding related applications This application claims priority to U.S. application 63/537,247, filed on September 8, 2023, which is incorporated herein in its entirety by reference. The present invention relates to magnetic levitation transfer systems and linear motors for transfer devices, systems and methods, for example, lithography devices and systems. A lithography device is a machine configured to apply a desired pattern onto a substrate. A lithography device can be used, for example, in the manufacture of an integrated circuit (IC). A lithography device can project a pattern of, for example, a patterning device (e.g., a mask, a reticle) onto a layer of a radiation-sensitive material (resist) provided on a substrate. To project a pattern onto a substrate, a lithography device may use electromagnetic radiation. The wavelength of this radiation determines the minimum size of features that can be formed on the substrate. A lithography device using extreme ultraviolet (EUV) radiation with a wavelength in the range of 4 to 20 nm, for example 6.7 nm or 13.5 nm, may be used to form smaller features on a substrate than a lithography device using deep ultraviolet (DUV) radiation with a wavelength of, for example 157 nm, 193 nm, or 248 nm. Linear motors with gas bearings have been used to control workpiece stages, but they are difficult to implement and can generate contaminant particles within the lithography apparatus. Furthermore, the complexity of gas bearing solutions is very high, and designing workpiece stages using gas bearings in a vacuum suffers from stiffness issues. Magnetic levitation-based linear motors avoid the need for gas bearings, provide low negative stiffness, and support the workpiece stage by magnetic force without any mechanical contact, thereby limiting the generation of contaminant particles. However, magnetic levitation systems can experience parasitic vertical forces, cogging, and instability. At high acceleration, it can become difficult to maintain an accurate gap or distance between the object stage and the linear motor. Additionally, magnetic levitation systems can be unstable due to very large negative stiffness, which can cause the system to move significantly out of center and naturally slide or flip over. The accompanying drawings included in and forming part of this specification illustrate embodiments, further explain the principles of the embodiments together with the description, and serve to enable a person skilled in the relevant technical field to create and use the embodiments. FIG. 1 is a schematic diagram of a lithography apparatus according to an exemplary embodiment. FIG. 2 is a schematic cross-sectional view of a linear motor according to an exemplary embodiment. FIG. 3 is a schematic cross-sectional view of a pair of linear motors using the linear motor shown in FIG. 2 according to an exemplary embodiment. FIG. 4 is a schematic front perspective view of a transfer system using the linear motor pair shown in FIG. 3 according to an exemplary embodiment. Figure 5 is a schematic front view of the transfer system shown in Figure 4. FIG. 5a is a schematic front view of an alternative transfer system using the linear motor pair shown in FIG. 3 according to an exemplary embodiment. FIG. 5b is a schematic front view of an alternative transfer system using inclined linear motor pairs according to an exemplary embodiment. FIG. 6 is a schematic diagram of a 3-phase control scheme for one or more linear motors according to an exemplary embodiment. FIG. 7 is a schematic diagram of a 4-phase control scheme for one or more linear motors according to an exemplary embodiment. FIG. 8 is a control flow diagram for a 3-phase control scheme for one or more linear motors according to an exemplary embodiment. FIG. 9 is a control flow diagram for a 4-phase control scheme for one or more linear motors according to an exemplary embodiment. FIG. 10 illustrates a control flow diagram for the transfer system shown in FIG. 4 and FIG. 5 according to an exemplary embodiment. The features of the embodiments and exemplary embodiments will become more apparent from the detailed description set forth below when taken together with the drawings, and identical reference letters in the drawings identify corresponding elements throughout. In the drawings, similar reference numbers indicate elements that are identical overall, functionally similar, and/or structurally similar. Additionally, generally, the leftmost number(s) of a reference number identify the drawing in which the reference number first appears. Unless otherwise specified, the drawings provided throughout this specification should not be interpreted as to-scale drawings. This specification discloses one or more embodiments comprising features of the present invention. The disclosed embodiments are merely illustrative of the present invention. The scope of the present