Lorentz Actuator Phase-Current Compensation for Parasitic Forces
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Lorentz actuators in lithographic apparatuses face issues with parasitic forces due to tolerances in actuator components, which affect dynamic performance, especially when increased accelerations are required for improved throughput.
Innovation Solution
A Lorentz actuator design with a movable magnet and coil arrangement, featuring a first and second coil portion that can be operated separately by a current controller to apply a phase difference in currents, compensating for parasitic reluctance and Lorentz forces in an auxiliary direction perpendicular to the main direction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If increased accelerations are applied to improve throughput, then productivity increases, but parasitic forces increase and negatively impact dynamic performance
Solution Approach 1:
The coil arrangement is divided into a first coil portion and a second coil portion that can be operated separately with different current phases. This segmentation allows independent control of force components, enabling compensation of parasitic forces while maintaining high acceleration for improved throughput.
Solution Approach 2:
The invention changes the phase parameter of currents supplied to different coil portions to compensate for parasitic forces. By applying a phase difference between currents in the first and second coil portions, the system can counteract parasitic reluctance and Lorentz forces while maintaining high acceleration levels for improved productivity.
2Device complexity
If conventional Lorentz actuators are used, then device complexity is low, but parasitic forces occur due to component tolerances
Solution Approach 1:
The coil arrangement is divided into a first coil portion and a second coil portion that can be operated separately with different current phases. This segmentation allows independent control of force components, enabling compensation of parasitic forces while maintaining high acceleration for improved throughput.
Solution Approach 2:
The invention converts the harmful parasitic forces into a controllable parameter by using phase-differenced currents to generate compensating forces. The parasitic forces that arise from component tolerances are counteracted by deliberately applying phase differences to create opposing force components, thereby eliminating the harmful effect.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design effectively mitigates parasitic forces, enhancing the dynamic performance and throughput of the lithographic apparatus by allowing precise control of forces in both the main and auxiliary directions.
Implementation Method 1
A lithographic apparatus usually comprises one or more objects that need to be positioned accurately with respect to each other, for instance the patterning device, the substrate and/or the supports thereof. To position these objects in a main direction, use can be made of well-known Lorentz actuators.
Implementation Method 2
the actuator comprises compensation coils to apply forces between the magnet arrangement and the coil arrangement in an auxiliary direction by supplying a current through the compensation coils
Implementation Method 3
a magnet arrangement; a coil arrangement; wherein the magnet arrangement and coil arrangement are moveable relative to each other in a main direction
Data Source
AI summary
A Lorentz actuator includes: a magnet arrangement; a coil arrangement; and a current controller for supplying a current to the coil arrangement; wherein the magnet and coil arrangement are moveable relative to each other in a main direction, wherein the coil arrangement has a first and second coil portion that are separately operable by the current controller, such that when the same current is supplied to the first coil portion as is supplied to the second coil portion, Lorentz forces generated in the main direction by the first and second coil portions are also the same, and wherein the current controller is configured to supply a current to the first and second coil portions with a phase difference in order to compensate for parasitic reluctance and/or Lorentz forces in an auxiliary direction perpendicular to the main direction.