Optical Proximity Correction Edge Interpolation
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Solution Overview
Problem
The optical proximity correction process in semiconductor lithography requires numerous iterations to converge on an accurate mask layout, leading to increased computing time and costs due to interactions between segment adjustments and the need for multiple iterations to compensate for optical proximity effects.
Innovation Solution
An optical proximity correction process that repeats a convergence process for each edge of the mask pattern, using interpolation to adjust positions based on target exposure intensities, reducing the number of iterations by calculating exposure intensities at both extended and shrunk pattern positions, thereby decreasing computing time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional OPC process with multiple iterations is used to achieve accurate mask layout, then manufacturing precision is improved, but loss of time increases
Solution Approach 1:
The patent applies preliminary action by performing an extrapolation pre-convergence process before the main convergence process. This pre-convergence step uses extrapolation to predict edge positions that are likely to converge, thereby reducing the number of iterations needed in the subsequent convergence process while maintaining manufacturing precision
Solution Approach 2:
The patent implements skipping by using extrapolation to jump ahead to predicted converged positions rather than iterating through all intermediate steps. This allows the process to rush through unnecessary iterations while still achieving accurate mask layout, thereby reducing computing time without sacrificing precision
2Productivity
If extrapolation pre-convergence process is performed before convergence process, then productivity is improved, but device complexity increases
Solution Approach 1:
The patent applies segmentation by dividing the convergence process into two distinct segments: an extrapolation pre-convergence process and a main convergence process. This segmentation allows each segment to specialize in different tasks, with the pre-convergence handling preliminary adjustments and the main convergence refining the result, thereby improving overall productivity while managing complexity through modular design
Data Source
AI summary
An optical proximity correction process for designing a mask according to a target exposure intensity of each edge of a pattern is provided. Each edge is at a corresponding current edge position which corresponds to a current exposure intensity. The process comprises repeating a convergence process on each edge to determine an adjusted position for the edge until an adjusted exposure intensity of the edge is equal to the target exposure intensity. For each edge, the convergence process comprises comparing the target exposure intensity with the current exposure intensity to determine an in-position correlating to a first exposure intensity and an out-position correlating to a second exposure intensity, wherein the target exposure intensity is within a range between the first and the second exposure intensities. An interpolation is performed to obtain the adjusted position according to the target exposure intensity. The pattern is updated according to the adjusted position.