Vibration Compensation via Derivative Acceleration
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Photolithography systems face distortion issues due to vibrations in lens barrels, which existing technologies attempt to address using accelerometers, but these sensors are costly and introduce noise delays.
Innovation Solution
A control system that detects and compensates for vibrations by processing position measurements to derive derivative acceleration, determining a compensatory force, and applying it to counteract vibrations without the need for accelerometers, utilizing position sensing and derivative control arrangements with piezoelectric actuators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If accelerometers are used to detect vibrations, then vibration detection accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the vibration detection function from dedicated accelerometer hardware and implements it through software-based derivative calculation using position sensor data. This removes the need for additional accelerometer components while maintaining vibration detection capability.
Solution Approach 2:
The position sensor serves multiple functions: it tracks the position of imaging elements for focus control and simultaneously provides data for vibration detection through derivative calculation. This multi-functionality eliminates the need for separate vibration sensing hardware.
2Measurement precision
If accelerometers are placed on the active lens mount, then vibration detection precision is improved, but ease of manufacture deteriorates
Solution Approach 1:
The patent removes the accelerometer component from the active lens mount and replaces it with software-based vibration detection using existing position sensor data. This eliminates the need for additional hardware installation on the lens mount.
Solution Approach 2:
The position sensing system serves itself by using its own position data to detect vibrations through derivative calculation. The system leverages existing infrastructure without requiring additional sensors or hardware modifications to the lens mount.
3Reliability
If accelerometers are used for vibration detection, then vibration compensation capability is improved, but noise and time delay increase
Solution Approach 1:
The patent replaces the mechanical accelerometer sensing system with a computational approach using derivative controllers. This substitution eliminates mechanical noise and time delays associated with physical sensors while maintaining vibration detection and compensation capability.
Solution Approach 2:
The system calculates derivative velocity and acceleration continuously from position data in advance, preparing vibration compensation signals proactively rather than reacting to accelerometer outputs. This preliminary calculation approach reduces time delay in the compensation loop.
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 approach effectively dampens vibrations in photolithography systems, reducing hardware costs and noise issues associated with accelerometers, while maintaining image integrity and semiconductor wafer quality.
Implementation Method 1
utilizing position sensing and derivative control arrangements with piezoelectric actuators
Data Source
AI summary
Methods and apparatus for providing vibration compensation using position measurements are disclosed. According to one aspect of the present invention, a method of compensating for vibrations of an object includes obtaining a plurality of position measurements associated with the object. The method also includes processing the plurality of position measurements to determine a derivative acceleration, and determining a compensatory force to counteract the vibrations of the object. Determining the compensatory force includes using the derivative acceleration. Finally, the method includes applying the compensatory force to the object.