Monolithic Stage Carrier with Linear EM Actuators for Six-DOF Motion
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Solution Overview
Problem
Microlithography systems face challenges in achieving precise and accurate motion of stages with six degrees of freedom, particularly in achieving all six DOFs with high accuracy and precision, while also requiring faster acceleration, deceleration, and higher velocities, which increases the size and mass of stages and actuators, necessitating a reduction in mass without compromising performance.
Innovation Solution
The implementation of a stage device with multiple linear EM actuators, including two-DOF and one-DOF linear motors, configured to provide motion in all six degrees of freedom (X, Y, Z, θX, θY, θZ) through a monolithic carrier design, with reaction masses and weight compensators for magnetic levitation and reduced size, allowing for efficient interferometric monitoring and adaptable motion ranges.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional multi-stage mechanisms are used to achieve six degrees of freedom, then motion accuracy can be maintained, but device complexity and mass increase
Solution Approach 1:
The patent combines multiple degrees of freedom into single actuators. Specifically, two-DOF linear motors provide motion in two orthogonal directions simultaneously, and three-DOF spherical actuators provide motion in three directions with a single component, eliminating the need for multiple separate actuators and reducing overall system complexity while maintaining six-DOF capability
Solution Approach 2:
The spherical actuators serve multiple functions simultaneously - each three-DOF spherical actuator provides motion in three orthogonal directions, and the two-DOF linear motors provide motion in two directions, allowing single components to perform what would traditionally require multiple specialized actuators
2Productivity
If stage velocity and acceleration are increased to improve throughput, then productivity increases, but mass and size of actuators must increase
Solution Approach 1:
The patent replaces conventional mechanical drive systems with electromagnetic actuators (linear motors and spherical electromagnetic actuators). These EM actuators provide higher acceleration and velocity capabilities without the mass penalties of mechanical transmission systems, enabling improved throughput without proportionally increasing actuator mass
Solution Approach 2:
The spherical actuators provide dynamic motion capability in multiple degrees of freedom simultaneously, allowing the stage to achieve higher velocities and accelerations through coordinated multi-axial motion rather than sequential movement, improving throughput without requiring oversized actuators
3Manufacturing precision
If six degrees of freedom are provided with high accuracy, then positioning precision is improved, but device complexity increases
Solution Approach 1:
The patent merges multiple DOFs into fewer actuators - three-DOF spherical actuators and two-DOF linear motors are used instead of six separate single-DOF actuators. This reduction in component count simplifies the overall system while maintaining full six-DOF positioning capability with high precision
Solution Approach 2:
The patent changes the fundamental parameters of the actuation system by using electromagnetic fields instead of mechanical linkages, and by using spherical motion geometry instead of conventional linear motion. These parameter changes enable six-DOF control with fewer components and simplified control algorithms
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 and efficient motion of reticle and substrate stages in microlithography systems, reducing mass and size while maintaining high accuracy and throughput, and allowing for the handling of larger objects with improved velocity and reduced vibration.
Implementation Method 1
multiple linear EM actuators (e.g., linear motors) coupling the carrier monolithically to a base
Implementation Method 2
reaction masses and weight compensators for magnetic levitation
Data Source
AI summary
Stage devices for various uses including use as a reticle stage or substrate stage in a microlithography system. An exemplary device includes a carrier and multiple linear EM actuators that couple the carrier monolithically to a base. The linear EM actuators collectively provide controlled movability of the carrier relative to the base in all six DOFs (X, Y, Z, θX, θY, θZ). The multiple linear EM actuators comprise at least one multiple-DOF linear actuator but fewer than six linear EM actuators. For example, the stage device can have two two-DOF linear actuators providing respective motions of the carrier in the X, Y and Y, Z DOFs (and collectively in all six DOFs) or can have two two-DOE linear actuators providing motions of the carrier in the Y, Z, θX, θY, and θZ DOFs and a one-DOF linear actuator providing motions in the X DOF.