Mask Patch Boundary Stitching for Curvilinear Pattern Continuity
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Solution Overview
Problem
Current lithographic technologies face challenges in accurately reproducing small features and high feature densities due to proximity effects, leading to issues like line end pull-back and reduced process windows, especially when using curvilinear masks with complex assist features.
Innovation Solution
A method is employed to adjust polygon portions at patch boundaries in a mask pattern using a stitching function to minimize differences between adjacent features, incorporating optical proximity correction and source optimization, and iteratively refining the mask pattern to ensure seamless joining and manufacturability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If curvilinear masks with complex assist features are used to improve feature reproduction accuracy, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The mask pattern is divided into multiple patches, with each patch containing a portion of the overall pattern. This segmentation allows complex curvilinear masks to be managed and processed in smaller, more manageable units, reducing the effective complexity while maintaining the ability to reproduce small features with high precision through iterative optimization of each patch
2Manufacturing precision
If optical proximity correction is applied to address line end pull-back, then manufacturing precision is improved, but process complexity increases
Solution Approach 1:
Optical proximity correction is performed iteratively on each patch before final assembly, with corrections applied in advance to compensate for anticipated line end pull-back effects. This preliminary correction action, combined with the segmentation approach, allows complex proximity effects to be managed systematically without overwhelming process complexity
3Manufacturing precision
If patch boundaries are optimized to minimize differences between adjacent features, then manufacturing precision is improved, but computation time increases
Solution Approach 1:
By segmenting the mask into patches, the computational domain is divided, allowing iterative optimization to be applied to smaller regions simultaneously. This reduces the computation time required for each iteration while maintaining the precision of pattern continuity at boundaries through careful stitching of optimized patch edges
Solution Approach 2:
The method applies iterative optimization to patches rather than the entire mask at once, using partial action on manageable segments. This approach achieves sufficient precision improvement at patch boundaries without the excessive computational time that would result from optimizing the complete mask pattern iteratively
Data Source
AI summary
A method for generating a mask pattern to be employed in a patterning process. The method including obtaining (i) a first feature patch including a first polygon portion of an initial mask pattern, and (ii) a second feature patch including a second polygon portion of the initial mask pattern; adjusting the second polygon portion at a patch boundary between the first feature patch and the second feature patch such that a difference between the first polygon portion and the second polygon portion at the patch boundary is reduced; and combining the first polygon portion and the adjusted second polygon portion at the patch boundary to form the mask pattern.