Lithographic Displacement Device Coil Levitation
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Solution Overview
Problem
Current displacement devices in lithographic apparatuses face challenges in adapting the center of force without requiring significant changes in design or space, and they often cause crosstalk that complicates the positioning of other components due to the magnetic fields generated by magnets and coil block units.
Innovation Solution
The displacement device features a configuration with a set of coil block units, including main and secondary coil block units, which allows for the adjustment of the center of force to align with the center of gravity without altering the space occupied, and reduces crosstalk by using a multi-phase system to control the position of the second part relative to the first part, primarily using coil block units of the same kind for levitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the center of force is adjusted by repositioning coil block units, then positioning precision is improved, but the device complexity and space requirements increase
Solution Approach 1:
The patent adjusts the center of force by changing the current distribution parameters in the coil block units rather than physically repositioning them. By varying the current magnitude and phase in existing coils, the effective center of force can be shifted to align with the center of gravity, achieving precise positioning without modifying the physical layout or adding complex mechanisms.
2Ease of operation
If magnets and coil block units are used to generate magnetic fields for positioning, then positioning capability is improved, but crosstalk with nearby positioning devices occurs
Solution Approach 1:
The patent employs periodic alternating current in the coil block units to generate magnetic fields for positioning. By using AC excitation with specific frequencies and phases, the magnetic field can be dynamically controlled to minimize crosstalk with nearby positioning devices while maintaining effective positioning capability through timed electromagnetic interaction.
3Adaptability or versatility
If multiple types of coil block units are used to provide force in different directions, then movement versatility is improved, but the difficulty of controlling the center of force increases
Solution Approach 1:
The patent makes all coil block units identical in structure and capable of providing force in multiple directions through controlled current distribution. Each coil block unit can generate force components in different directions by adjusting the current phase and magnitude, eliminating the need for specialized coil units for different directions and simplifying the overall control system.
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 configuration enables precise positioning and levitation of the second part relative to the first part, minimizing the impact on nearby positioning devices and allowing for efficient movement in multiple degrees of freedom while maintaining a consistent center of force alignment with the center of gravity.
Implementation Method 1
two coil block units are of a first kind in which current conductors are oriented in the second direction to apply a force between the first and second part in the first direction based on Lorentz law. The other two coil block units are of a second kind in which current conductors are oriented in the first direction to apply a force between the first and second part in the second direction based on Lorentz law.
Implementation Method 2
If also the current conductors are used to levitate the second part, a levitation force can be applied independently from the force in the first or second direction, thereby allowing full control of the movement of the stage system in all applicable directions.
Data Source
AI summary
A displacement device with a first and second part which are displaceable relative to one another, the first part being provided with a system of magnets, the second part being provided with a set of coil block units including: at least three first coil block units having current conductors oriented parallel to a second direction, at least two second coil block units having current conductors oriented parallel to a first direction, wherein the displacement device includes a controller configured to control the position of the second part relative to the first part, and wherein when the second part mainly moves in the second direction the controller is configured to levitate the second part from the first part in the third direction by using first coil block units only.