Optical Proximity Correction Target Point Placement
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Solution Overview
Problem
Conventional optical proximity correction (OPC) methods suffer from low precision due to fixed target point placement, leading to insufficient or over-correction issues, which limits adaptability to different patterns and results in low correction efficiency and accuracy.
Innovation Solution
A method and system for OPC that dynamically sets target points at the tangent points of segments, where the tangent point coincides with the end of the curve of the simulated pattern, allowing for maximal edge placement error (EPE) calculation and correction, thereby reducing the number of correction iterations and improving precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If fixed target point placement is used in OPC, then the method is simple to implement, but the correction precision is low and adaptability to different patterns is insufficient
Solution Approach 1:
The patent transforms the static, fixed target point placement into a dynamic approach where target points are adaptively determined based on pattern characteristics. The system dynamically identifies critical regions and sets target points at locations with maximum EPE impact, allowing the correction process to adapt to different pattern geometries and achieve higher precision without sacrificing implementation feasibility
Solution Approach 2:
The patent applies local quality by differentiating target point placement strategies based on local pattern characteristics. Instead of using a uniform fixed placement rule, the system analyzes local EPE distribution and places target points specifically at locations where correction is most needed, such as at the ends of curves or segments with high sensitivity to dimensional changes
2Ease of manufacture
If fixed target point placement is used in OPC, then the implementation is straightforward, but insufficient-correction or over-correction problems occur
Solution Approach 1:
The patent implements feedback mechanisms by calculating EPE at multiple points and using this information to guide target point placement. The system continuously monitors EPE distribution and adjusts target point locations accordingly, preventing both insufficient-correction (by placing points where EPE is highest) and over-correction (by avoiding points where EPE is already within tolerance)
3Device complexity
If conventional OPC method is used, then the process is simple, but the number of correction iterations is high (3-8 rounds)
Solution Approach 1:
The patent applies preliminary action by pre-identifying critical segments and target points before the main correction process begins. By analyzing pattern characteristics in advance and selecting optimal target point locations, the system prepares the correction strategy beforehand, reducing the number of iterative rounds needed to achieve convergence and improving overall correction efficiency
Data Source
AI summary
An optical proximity correction method, comprising: dissecting an edge of a design pattern (120/220) to form a segment (Seg1/Seg2); setting target points of the segments (Seg1/Seg2), and if the segments (Seg1/Seg2) translate in a direction vertical to the segments (Seg1/Seg2), controlling tangent points (P1/P2) of the segments (Seg1/Seg2) tangent to a simulated pattern (110/210) to coincide with the target points; computing edge position differences of the target points; and correcting the design pattern (120/220) according to the edge position differences.