Imprint Lithography Substrate Stress Relaxation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
In imprint lithography, mechanical stress induced in substrates during patterning can lead to strain and misalignment of patterns, resulting in reduced device yield and wastage due to slippage between the substrate and the substrate holder or adhesion issues with the imprint template.
Innovation Solution
A method and apparatus that allow for the relaxation of mechanical stress in substrates by partially or fully unclamping a portion of the substrate from the substrate holder after imprinting, using techniques such as electrostatic or magnetic attraction, vacuum clamping, or overpressure to separate the substrate, thereby relaxing strain and improving alignment accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the substrate is clamped to the substrate holder during imprint lithography, then the substrate can be held in position for patterning, but mechanical stress and strain accumulate in the substrate leading to misalignment of subsequently applied patterns
Solution Approach 1:
The substrate is unclamped between imprinting operations to relax mechanical stress before subsequent patterning. This preliminary stress relaxation action prevents accumulation of strain that would otherwise cause misalignment in later steps, ensuring consistent pattern alignment across multiple lithography operations.
Solution Approach 2:
The clamping and unclamping of the substrate is performed periodically - clamped during imprinting to maintain position, then unclamped to relax stress, then re-clamped for the next imprinting operation. This periodic cycle of clamping and unclamping prevents stress accumulation while maintaining positioning accuracy throughout the multi-step lithography process.
2Stability of the object's composition
If high clamping force is applied to hold the substrate, then the substrate remains stable during imprinting, but slippage occurs between substrate and substrate holder due to mechanical stress
Solution Approach 1:
The substrate is unclamped between imprinting steps to allow stress relaxation and prevent slippage. By releasing the clamping force temporarily, the substrate can adjust without accumulating stress that would lead to positioning errors in subsequent operations.
Solution Approach 2:
The clamping force is dynamically adjusted - applied during imprinting to ensure substrate stability, then released to allow stress relaxation. This dynamic control of clamping force optimizes both substrate stability during patterning and positioning accuracy between steps.
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
The relaxation of mechanical stress improves the accuracy of pattern alignment across the substrate, reducing wastage and enhancing the yield of processed devices by minimizing compressive and tensile stress caused by imprinting processes.
Implementation Method 1
using techniques such as electrostatic or magnetic attraction
Implementation Method 2
using techniques such as electrostatic or magnetic attraction
Implementation Method 3
vacuum clamping
Data Source
AI summary
An imprint lithography apparatus and manufacturing method can lead to mechanical stress being formed in a substrate to which an imprint pattern is being applied. This may cause strain within the substrate leading to misalignment of a subsequent pattern with an earlier pattern in a part of the substrate, which is strained. An apparatus and method is disclosed which allows for stress relaxation in the substrate prior to further patterning to reduce, minimize or prevent such misalignment from residual strain. This is achieved by locally unclamping a portion of substrate (including optionally the entire substrate) from a corresponding portion of substrate holder so that mechanical stress leading to local strain may relax prior to further patterning. To overcome residual frictional force between the substrate and substrate holder, the substrate and substrate holder may be physically separated prior to further patterning.