Stator Holder Segmentation for Eddy Current Cancellation
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Solution Overview
Problem
Electromagnetic drives in projection exposure apparatuses for semiconductor lithography face inefficiencies due to parasitic eddy currents induced in the stator holder, which can lead to reduced energy conversion efficiency and system instability, particularly at high frequencies, and existing solutions like using non-conductive materials or insulating slots are either complex or ineffective.
Innovation Solution
The electromagnetic drive features a stator holder with at least two electrically conductive paths arranged in a path pair, where the paths are connected at their ends and designed to induce eddy currents in opposite directions, effectively canceling each other out, thereby minimizing the magnetic field generated by the stator holder and reducing inductive coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If a conductive material is used for the stator holder to dissipate heat, then thermal conductivity is improved, but parasitic eddy currents are induced reducing energy conversion efficiency
Solution Approach 1:
The stator holder is divided into multiple electrically isolated segments or paths. Each segment is electrically insulated from the others, preventing continuous eddy current loops while maintaining thermal conductivity within each segment. This segmentation breaks the electrical continuity required for parasitic eddy currents while preserving heat dissipation capability through the conductive material structure.
Solution Approach 2:
Different regions of the stator holder are assigned different electrical properties. The areas in close proximity to the coil are designed with electrical insulation or non-conductive characteristics to minimize eddy current induction, while other regions maintain good thermal conductivity for heat dissipation. This local differentiation allows simultaneous optimization of both thermal management and electromagnetic performance.
2Loss of energy
If a non-conductive material is used for the stator holder to prevent eddy currents, then energy conversion efficiency is improved, but heat dissipation capability deteriorates
Solution Approach 1:
The stator holder employs composite material structures combining conductive and insulating properties. This may include conductive materials with embedded insulating patterns, layered composite structures, or hybrid materials that provide both thermal conductivity and electrical insulation characteristics. The composite approach enables simultaneous achievement of heat dissipation and eddy current prevention.
3Loss of energy
If insulating slots are introduced to reduce eddy currents, then energy conversion efficiency is improved, but device complexity increases
Solution Approach 1:
The stator holder is divided into multiple electrically isolated segments or paths. Each segment is electrically insulated from the others, preventing continuous eddy current loops while maintaining thermal conductivity within each segment. This segmentation breaks the electrical continuity required for parasitic eddy currents while preserving heat dissipation capability through the conductive material structure.
Solution Approach 2:
Different regions of the stator holder are assigned different electrical properties. The areas in close proximity to the coil are designed with electrical insulation or non-conductive characteristics to minimize eddy current induction, while other regions maintain good thermal conductivity for heat dissipation. This local differentiation allows simultaneous optimization of both thermal management and electromagnetic performance.
4Loss of energy
If the coil is extended to increase distance from the stator holder, then parasitic magnetic field effect is reduced, but structural size and vibration transmission increase
Solution Approach 1:
Different regions of the stator holder are assigned different electrical properties. The areas in close proximity to the coil are designed with electrical insulation or non-conductive characteristics to minimize eddy current induction, while other regions maintain good thermal conductivity for heat dissipation. This local differentiation allows simultaneous optimization of both thermal management and electromagnetic performance.
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 significantly reduces the inductive coupling factor between the stator and the stator holder, minimizing parasitic eddy currents and maintaining efficient heat dissipation, leading to a reliable and stable electromagnetic drive for adjusting optical elements in semiconductor lithography.
Implementation Method 1
electromagnetic drives based on the known physical phenomena of the Lorentz force or reluctance force
Implementation Method 2
electromagnetic drives based on the known physical phenomena of the Lorentz force or reluctance force
Implementation Method 3
The current flow in the coil generates a magnetic field which, aside from the desired effect on the translator or rotor, additionally induces parasitic eddy currents in nearby conductive materials such as the coil holder
Implementation Method 4
induces eddy currents acting in opposite directions in the paths
Data Source
AI summary
An electromagnetic drive includes a stator, having a stator holder and an actuating element which is movable by electromagnetic interaction with the stator. The stator holder has at least two electrically conductive paths running separately from and adjacent to one another. In each case, the two paths running separately from and adjacent to one another form a path pair, and the paths of the path pair are connected to one another in electrically conductive fashion at their respective ends. The paths of the path pair are arranged such that the stator and/or the actuating element induces eddy currents acting in opposite directions in the paths.