Magnification Ramp Synchronization for Template Slippage
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Solution Overview
Problem
In nanoimprint lithography, the uneven ramping of forces applied by actuators leads to template slippage and registration errors due to in-balance forces, particularly before the template contacts the substrate during the dispensing of liquid curable resist.
Innovation Solution
A method and system for supplying control signals to force actuators, ensuring that all actuators reach their defined force values at the same initial time and reduce forces to individual set points at the same final time, maintaining force balance and preventing template slippage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If magnification forces are ramped up to threshold level using conventional trajectories, then template distortion correction is achieved, but template slippage and registration errors occur due to unbalanced forces
Solution Approach 1:
The system continuously monitors the position and force balance of multiple actuators during the magnification ramp process. When detection indicates that forces are becoming unbalanced or the template shows signs of slippage, the control algorithm automatically adjusts individual actuator forces to restore balance, preventing registration errors and maintaining template stability throughout the dispensing process
Solution Approach 2:
The patent implements dynamic magnification trajectories that adapt in real-time based on the actual state of the template and actuators. Instead of fixed ramp profiles, the system continuously modifies force application rates and magnification levels to maintain force balance across all actuators, ensuring template stability while achieving the required distortion correction
2Manufacturing precision
If five separate ramp trajectories are used for distortion setpoints, then comprehensive distortion correction is achieved, but actuator force imbalance occurs causing template slippage
Solution Approach 1:
The system merges the control of multiple distortion parameters (MagX, MagY, Skew, TrapX, TrapY) into a unified magnification trajectory framework. Instead of independently managing five separate trajectories, the algorithm coordinates them to work together, ensuring that all actuators follow a synchronized force profile that maintains balance while achieving comprehensive distortion correction
3Adaptability or versatility
If actuators reach upper limit at different times, then individual actuator constraints are satisfied, but in-balance forces cause registration errors
Solution Approach 1:
The control algorithm predicts which actuators will reach their upper limits first based on their current force levels and ramp rates. Before actual imbalance occurs, the system pre-adjusts the trajectories of actuators that are approaching their limits, slowing their ramp rate or modifying their force profile to ensure they reach the upper limit simultaneously with other actuators, thereby maintaining force balance and preventing registration errors
Data Source
AI summary
A method and system for supplying control signals to two or more force actuators wherein each of the two or more force actuators having a defined force value. The method includes sending a first set of control signals to each of the actuators to ramp forces supplied to reach the defined force value at a same initial defined value time and sending a second set of control signals to each of the actuators to reduce the forces supplied starting at a same final defined value time to individual set point values, and wherein each of the two of more force actuators reach their individual set point values at a same set point time.