Imprint Lithography Separation Strain Control
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Solution Overview
Problem
Current imprint lithography techniques suffer from defects such as sheared, pulled-out, and torn features due to strain mismatch between templates and substrates during separation, particularly in areas with high feature density transitions, and lack consideration of separation forces, pressures, and kinetics.
Innovation Solution
The solution involves matching the stiffness of the template and substrate by adjusting their thickness and adding a stiffening layer, varying the magnitude and velocity of applied forces, and using feedback and monitoring to control the separation process, along with employing dummy fill patterns and modifying chuck designs to minimize shearing and pulling stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If template and substrate are separated after imprinting, then the imprinted pattern is transferred to the substrate, but strain mismatch causes sheared, pulled-out, and torn features
Solution Approach 1:
The patent applies parameter changes by carefully controlling separation forces, separation velocity, and pressure gradients during the template-substrate separation process. By optimizing these parameters, the patent achieves complete pattern transfer while preventing feature damage that would otherwise occur due to strain mismatch.
Solution Approach 2:
The patent employs dynamics by using time-varying separation forces and controlled separation velocity profiles. The separation process is dynamically adjusted to match the strain properties of the template and substrate, ensuring that features are released intact while maintaining pattern transfer quality.
2Productivity
If separation forces are increased to ensure complete pattern transfer, then more features are released from the template, but feature damage increases due to shearing and pulling stress
Solution Approach 1:
The patent applies periodic action through a multi-stage separation process with varying force levels. The separation occurs in controlled stages with different velocity profiles, allowing complete pattern transfer at lower stresses while preventing feature damage that would result from single high-force separation events.
Solution Approach 2:
The patent uses dynamic control of separation forces, adjusting the magnitude and rate of force application based on the strain properties of the materials. This dynamic approach enables complete feature release while maintaining feature integrity by avoiding excessive shear and pulling stresses.
3Adaptability or versatility
If template and substrate have different thicknesses and stiffness, then fabrication flexibility is improved, but strain mismatch during separation causes imprint defects
Solution Approach 1:
The patent compensates for stiffness differences by changing the separation process parameters - specifically adjusting separation forces, velocities, and pressure gradients to match the strain properties of each material combination. This allows flexible template and substrate design while maintaining pattern quality.
Solution Approach 2:
The patent employs feedback mechanisms to monitor and adjust separation parameters based on the actual strain response of the template-substrate system. This feedback control ensures that separation occurs without feature damage even when templates and substrates have different thicknesses and stiffness properties.
4Productivity
If separation velocity is increased to improve throughput, then production efficiency increases, but feature damage increases due to inertial effects and sudden stress
Solution Approach 1:
The patent uses periodic action with optimized separation velocity profiles that balance throughput and feature integrity. By controlling the timing and rate of separation, the patent achieves high productivity while preventing inertial damage and sudden stress effects that would occur with excessively fast separation.
Solution Approach 2:
The patent applies preliminary anti-action by pre-conditioning the template-substrate system before separation. The controlled separation velocity profile anticipates and prevents inertial effects and sudden stress by gradually increasing separation rate, thereby protecting features while maintaining throughput.
Data Source
AI summary
Systems and methods for improving robust layer separation during the separation process of an imprint lithography process are described. Included are methods of matching strains between a substrate to be imprinted and the template, varying or modifying the forces applied to the template and/or the substrate during separation, or varying or modifying the kinetics of the separation process.