Linear Motor Active Compensation for Lithography Stage Vibrations
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Solution Overview
Problem
Conventional digital lithography systems face challenges in compensating for parasitic forces such as vibrations generated by linear motors, which lead to undesirable effects like mura and edge roughness in mask patterns during the printing process.
Innovation Solution
The system incorporates active vibration compensators coupled to motor coils, which are mounted between upper and lower plates of the yoke tracks, and include accelerometers and moving masses to measure and counteract vibrations, ensuring precise movement and pattern quality.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If linear motors are used to move the stage, then the stage movement speed and positioning capability are improved, but parasitic forces such as vibrations are generated that deteriorate pattern quality
Solution Approach 1:
The patent uses the vibrations generated by linear motors to drive piezoelectric actuators that activate spring-loaded bumpers, converting the harmful vibrational energy into a beneficial counteracting force through mechanical impact absorption
Solution Approach 2:
The piezoelectric actuators are driven by periodic signals synchronized with the motor vibrations, creating rhythmic activation of the spring-loaded bumpers that continuously counteract the parasitic vibrations at their frequency
2Object-affected harmful factors
If conventional vibration compensation methods are used, then some vibration reduction is achieved, but compensation for forces perpendicular to motion directions remains difficult
Solution Approach 1:
The patent addresses perpendicular direction vibrations by positioning spring-loaded bumpers on side walls of the guide rails, extending vibration compensation from the traditional horizontal plane to vertical and lateral dimensions through three-dimensional bumper placement
3Object-affected harmful factors
If active vibration compensators are added to the system, then vibration compensation capability is improved, but system complexity increases
Solution Approach 1:
The system uses its own motor-driven vibrations to power the piezoelectric actuators that activate the vibration compensation mechanism, making the compensators self-powered and eliminating the need for separate power sources or control systems
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 solution effectively compensates for parasitic forces, enhancing the quality of printed patterns by actively counteracting vibrations and disturbances, thereby improving the overall performance of the digital lithography system.
Implementation Method 1
measuring vibrations from the motor coils during operation of the digital lithography system with an accelerometer disposed in each active compensator
Implementation Method 2
actuating a moving mass disposed in each active compensator of the one or more active compensators in a direction opposite of the vibrations from the motor coils
Implementation Method 3
A conventional digital lithography system utilizes linear motors to move a stage when printing patterns. During operation of a lithography system, movements of the stage results in motor generated parasitic forces such as vibrations
Data Source
AI summary
Embodiments of the present disclosure relate to a linear motor system and a digital lithography system having the linear motor system that compensates for potential parasitic forces applied to at least one stage of the digital lithography system during operation. The digital lithography system includes one or more motor coils disposed between an upper plate and a lower plate of a yoke of at least one track. The motor coils are each coupled to a mount which is coupled to a stage. Each mount includes one or more active compensators. During a digital lithography operation, the active compensators are in communication with the controller, The active compensators provides a force in the opposite direction of the parasitic forces, such as vibrations and other disturbances. The compensation of the parasitic forces increases the quality of the patterns printed by the digital lithography system.