Force Feedback Leveling for Polymer Pen Nanolithography Arrays
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Solution Overview
Problem
Polymer pen lithography faces challenges in achieving precise leveling between the pen array and the substrate surface, leading to variations in feature dimensions due to tilting, which limits its applicability to patterning small areas rather than full wafers.
Innovation Solution
A method involving the measurement of total force exerted by the pen array on the surface, with adjustments to the angular disposition to achieve leveling, utilizing a force sensor to determine optimal angles and ensure precise contact across the array, allowing for accurate feature size control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If optical microscopy is used to level the tip array by observing tip deformation, then the leveling process can be performed, but the measurement precision is insufficient to resolve tilts less than 0.02°, resulting in significant variations in feature edge length
Solution Approach 1:
The patent replaces the optical microscopy system with a force sensor system to measure the total force exerted by the pen array on the substrate. This mechanical measurement approach enables detection of tilts at the level of 1.6×10^-4 degrees, far surpassing the optical method's 0.02° resolution limit and eliminating the trade-off between measurement precision and feature uniformity.
Solution Approach 2:
The patent introduces a force sensor as an intermediary measurement device between the pen array and the substrate. By measuring the total force exerted by the array, the force sensor provides a sensitive indicator of tilting that can be used to precisely level the array, serving as a mediator that enables high-precision leveling without direct optical observation of the tips.
2Ease of operation
If the pen array is tilted to compensate for substrate non-planarity, then contact with the substrate can be achieved, but the feature dimensions vary across the surface due to unequal tip contact
Solution Approach 1:
The patent implements a feedback mechanism where the total force measured by the force sensor is used to determine the current tilt state of the pen array. This feedback information is then used to adjust the array orientation, creating a closed-loop system that maintains uniform tip contact across the substrate surface and eliminates feature dimension variations.
Solution Approach 2:
The patent changes the measurement parameter from optical deformation observation to mechanical force measurement. By monitoring the total force exerted by the pen array, the system can detect and compensate for tilting, adjusting the array orientation to maintain optimal contact across the entire substrate area.
3Ease of manufacture
If transmitted light is used for optical leveling, then the leveling process can be performed, but the array architecture and materials are limited
Solution Approach 1:
The patent replaces the optical transmission method with a mechanical force sensing method. This substitution eliminates the need for transmitted light, thereby removing the constraint on array architecture and material selection. The force sensor can measure the total force exerted by the pen array regardless of the materials used or the specific array structure.
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 method enables precise leveling of the pen array with tilt accuracy of less than 1.6×10−4 degrees, resulting in uniform feature diameters varying by only about 50 nm over a distance of 1 cm, enhancing the capability to pattern large areas with consistent feature sizes.
Implementation Method 1
The tips and the common substrate layer being formed from an elastomeric polymer or elastomeric gel polymer
Data Source
AI summary
A method of leveling a polymer pen array includes contacting a pen array with a surface and measuring a total force exerted on the surface by the pen array, the pen array being disposed at a first angle with respect to a first axis of the surface and a second angle with respect to a second axis of the surface; tilting one or both of the pen array and the surface to vary the first and second angles of the pen array with respect to the surface; measuring the total force exerted by the tilted pen array on the surface; and repeating the tilting and measuring steps until a global maximum of the total force exerted on the surface by the pen array is measured, thereby determining first and second angles which correspond to a leveled position of the pen array with respect to the surface.