Point-Based OPC for Lithography Mask Design
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Solution Overview
Problem
Current optical proximity correction (OPC) techniques in lithography face inefficiencies due to convergence issues, limited process window size, and high computational resource requirements, making them unsuitable for production lines.
Innovation Solution
The implementation of a point-based OPC method, referred to as 'all-angle OPC,' which adjusts mask points to optimize a cost function, allowing for finer control of mask design and improving lithography performance by generating curvilinear or hybrid patterns that are more natural and efficient.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional optical proximity correction (OPC) techniques are used, then pattern transfer accuracy can be improved, but computational resource requirements increase significantly and convergence issues arise
Solution Approach 1:
The patent segments the mask pattern into discrete control points (e.g., 5-10 points per feature) that can be independently adjusted. This segmentation transforms the continuous optimization problem into a discrete one, reducing computational complexity while maintaining the ability to achieve high pattern transfer accuracy through precise control of individual points.
Solution Approach 2:
The patent applies partial action by adjusting only the most critical mask points (control points) rather than optimizing every pixel or continuous parameter. This selective approach achieves sufficient pattern transfer accuracy without the excessive computational resources required by full-field optimization methods.
2Manufacturing precision
If conventional OPC techniques are used, then edge placement accuracy can be improved, but the process window remains limited
Solution Approach 1:
The patent changes the optimization parameters from continuous pixel values to discrete control point positions. By adjusting the locations of these control points, the method achieves both improved edge placement accuracy and an expanded process window, as the discrete parameter space allows for greater robustness against process variations.
3Manufacturing precision
If conventional OPC techniques are used, then pattern fidelity can be improved, but convergence issues prevent production line implementation
Solution Approach 1:
The patent inverts the conventional OPC approach by starting with a simplified discrete control point representation rather than attempting to optimize the complete continuous pattern. This inverted approach ensures convergence by working with a manageable parameter space that is guaranteed to converge, while still achieving high pattern fidelity through the discrete control points.
4Manufacturing precision
If complex mask designs are generated, then lithography performance can be improved, but computational demands increase
Solution Approach 1:
The patent segments complex mask designs into a small number of controllable points per feature (5-10 points). This segmentation maintains the ability to generate sophisticated curvilinear and hybrid patterns while dramatically reducing computational complexity, as the discrete point representation requires far fewer calculations than continuous pattern optimization.
Data Source
AI summary
A method for improving a design of a patterning device. The method includes (i) obtaining mask points of a design of a mask feature, wherein the mask feature corresponds to a target feature in a target pattern to be printed on a substrate; and (ii) adjusting locations of the mask points to generate a modified design of the mask feature based on the adjusted mask points.