Stage Device Linear Motor Magnetic Force Cancellation
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Solution Overview
Problem
Existing stage devices for semiconductor probe inspection face challenges with increased substrate weight, leading to issues with cogging and yawing due to magnetic attractive forces, and existing solutions either lack sufficient thrust or increase costs with magnetic-attractive-force-canceling technologies.
Innovation Solution
A stage device design featuring a rectangular boxy body with core-equipped linear motors arranged at the same height to cancel out magnetic attractive forces, providing high thrust and rigidity while minimizing vibration and cost through a gantry structure that supports both X-axis and Y-axis movements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a core-equipped linear motor with large thrust is used to drive the heavy stage, then the stage can be driven with sufficient force, but cogging or yawing occurs due to magnetic attractive force
Solution Approach 1:
The patent applies asymmetry by arranging linear motors of different types (core-equipped and coreless) in an asymmetric configuration rather than using identical motors symmetrically. Specifically, core-equipped linear motors providing large thrust are positioned on one side while coreless linear motors are positioned on the other side, creating an asymmetric motor arrangement that balances magnetic forces while maintaining driving capability.
Solution Approach 2:
The patent uses the counterweight principle by positioning coreless linear motors opposite to core-equipped linear motors to counterbalance the magnetic attractive forces. The coreless motors generate equal and opposite magnetic forces that cancel out the cogging and yawing effects produced by the core-equipped motors, effectively neutralizing the harmful magnetic forces while preserving the necessary thrust.
2Object-affected harmful factors
If a coreless linear motor is used to suppress cogging or yawing, then magnetic attractive force is reduced, but the thrust becomes weak and insufficient for driving the heavy stage
Solution Approach 1:
The patent merges two different types of linear motors (core-equipped and coreless) into a single integrated driving system. The core-equipped linear motors provide the necessary large thrust for driving the heavy stage, while the coreless linear motors simultaneously suppress cogging and yawing. This combination allows the system to achieve both high thrust and low magnetic interference that would be impossible with either motor type alone.
3Force
If the stage is made lightweight to compensate for weak thrust, then the coreless linear motor can drive the stage, but the rigidity of the stage is lowered and vibration resistance decreases
Solution Approach 1:
The patent uses counterweight by introducing coreless linear motors that generate opposing magnetic forces to balance the forces from core-equipped motors. This force balancing allows the system to maintain full stage weight without requiring lightweight construction, as the magnetic forces are properly balanced and the stage can retain its full rigidity and vibration resistance.
4Measurement precision
If a magnetic-attractive-force-canceling-type linear motor is used to suppress cogging or yawing, then high-speed movement and accurate position control are achieved, but the cost increases
Solution Approach 1:
The patent combines conventional core-equipped linear motors with coreless linear motors in a hybrid configuration to achieve the performance of expensive magnetic-attractive-force-canceling motors at lower cost. By using standard core-equipped motors for thrust and adding relatively inexpensive coreless motors for force balancing, the system achieves high-speed movement and accurate position control without requiring costly specialized motors.
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 enables high-speed and precise position control, suppressing cogging and yawing, and maintaining structural rigidity and vibration resistance, thus enhancing the reliability of semiconductor probe inspection.
Implementation Method 1
the core-equipped linear motor has a problem in that cogging or yawing occurs due to a magnetic attractive force
Implementation Method 2
a pair of X-axis linear motors configured to move the loading part in the X-axis direction inside the boxy body, and a pair of Y-axis linear motors configured to move the boxy body in the Y-axis direction, wherein the pair of X-axis linear motors are provided at the same position in a Z-axis direction
Data Source
AI summary
A drive unit of a stage device includes a boxy body having a rectangular shape in a plan view, a base, a pair of X-axis linear motors, and a pair of Y-axis linear motors. An X-axis stator is disposed on each of two mutually opposing X-axis-direction side walls of the boxy body, wherein magnetic attractions that draw respective X-axis rotors toward the X-axis stator side (Y-axis direction) cancel out each other between the pair of X-axis linear motors. A Y-axis stator is disposed on the inside of each of two mutually opposing Y-axis wall members, wherein magnetic attractions that draw respective Y-axis rotors toward the Y-axis stator side (X-axis direction) cancel out each other between the pair of Y-axis linear motors.