Mask Pattern Curvature for Proximity Effect Control
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Solution Overview
Problem
Current mask pattern generation methods face challenges in accurately transferring design layouts to substrates due to proximity effects and manufacturing constraints, particularly when features are close together, leading to inaccuracies and increased process variation margins.
Innovation Solution
A method that identifies target features with tight gaps and applies curvature to mask features to satisfy manufacturing constraints while maintaining performance metrics, using a computer-readable medium with instructions to simulate and modify mask patterns to ensure accurate edge placement and process window tolerance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional mask pattern generation methods are used, then manufacturing process is simple, but manufacturing precision deteriorates due to proximity effects and inability to satisfy mask manufacturing constraints
Solution Approach 1:
The patent applies curvature modification selectively to specific mask features based on their proximity to other features and violation of manufacturing constraints. Instead of uniformly modifying all features, the system identifies target features with tight gaps and applies curvature only to those features, thereby improving pattern transfer accuracy locally while minimizing unnecessary modifications elsewhere.
Solution Approach 2:
The patent applies curvature to mask features by transforming sharp corners into rounded shapes. This curvature modification helps satisfy mask manufacturing constraints (MRC) by increasing the effective spacing between adjacent features, thereby preventing proximity effects and improving the accuracy of pattern transfer to the substrate.
2Manufacturing precision
If mask features are modified to satisfy manufacturing constraints, then manufacturing precision improves, but computation time increases
Solution Approach 1:
The patent divides the mask pattern into individual features and processes each feature independently to determine whether curvature modification is needed. By segmenting the analysis to focus only on target features that violate manufacturing constraints, the system avoids unnecessary computations on features that already satisfy constraints, thereby reducing overall computation time while maintaining edge placement accuracy.
Solution Approach 2:
The patent applies curvature modification only to the extent necessary to satisfy mask manufacturing constraints for specific target features. Rather than applying excessive modifications to all features, the system performs partial action only where needed, optimizing the balance between improving edge placement accuracy and minimizing computation time.
3Reliability
If curvature is applied to mask features, then process window tolerance improves, but manufacturing complexity increases
Solution Approach 1:
The patent applies curvature modification locally to specific mask features that require it to improve process window tolerance. By limiting curvature application to only those features that violate manufacturing constraints, the system improves reliability where needed while minimizing the overall complexity of mask fabrication.
Data Source
AI summary
A method for generating a mask pattern for a patterning process. The method includes obtaining (i) a subset of target features (e.g., features too close) within a target pattern, the subset of target features having physical characteristic values below a threshold value, and (ii) an initial mask pattern (e.g., using an existing OPC process) associated with the target pattern; and modifying, based on a mask manufacturing constraint and a performance metric of the patterning process, one or more features of the initial mask pattern corresponding to the subset of target features to generate the mask pattern, the modifying including applying a curvature to a portion of the one or more features of the initial mask pattern.