Optical Proximity Effect Correction Using Line End Shortening Lookup Table
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Solution Overview
Problem
The increasing severity of line end shortening in photolithography patterns due to optical diffraction effects leads to poor convergence and prolonged correction times in optical proximity effect correction (OPC) processes, affecting semiconductor manufacturing efficiency.
Innovation Solution
An optical proximity effect correction method that involves fabricating a test pattern mask, establishing an OPC model, determining an initial correction value from a line end shortening rule table, and iteratively correcting the target pattern until the desired line end shortening is achieved, improving convergence and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If model-based optical proximity correction is used to correct line end shortening, then manufacturing precision is improved, but correction time increases significantly
Solution Approach 1:
The patent pre-calculates and stores line end shortening data for various pattern configurations in a lookup table before actual OPC processing. During correction, the system directly queries this pre-prepared table to obtain initial correction values, avoiding time-consuming real-time calculations while maintaining correction accuracy
Solution Approach 2:
The patent creates a simplified lookup table that copies and stores pre-computed line end shortening characteristics for different pattern types. This table serves as a reference database that provides quick access to correction parameters, replacing complex real-time optical modeling with efficient data retrieval operations
2Manufacturing precision
If patterns are moved outward by large distances to compensate for line end shortening, then manufacturing precision is improved, but OPC convergence becomes poor
Solution Approach 1:
The patent applies different correction strategies to different pattern types based on their specific characteristics. By categorizing patterns and selecting appropriate correction methods for each type, the system achieves accurate correction without causing convergence issues that would result from uniform large-distance movements
Solution Approach 2:
The system pre-determines appropriate correction values from the lookup table based on pattern characteristics before performing OPC. This preliminary selection of correction parameters prevents excessive pattern movements and guides the correction process toward convergence from the outset
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This method enhances the convergence of OPC, reduces correction time, and improves semiconductor manufacturing efficiency by effectively addressing line end shortening issues in photolithography.
Implementation Method 1
the optical diffraction effect is becoming more serious, and the patterns will have quite great line end shortening. This distortion deviation comes from the spatial optical image distortion caused by the loss of high-frequency information in the photolithography diffraction imaging process.
Data Source
AI summary
A optical proximity effect correction method includes: fabricating a test pattern mask according to design rules of a target pattern; obtaining data required by an optical proximity effect correction model, and establishing the optical proximity effect correction model; obtaining line end shortening data of the test pattern, and establishing a line end shortening rule table; determining an initial correction value according to the line end shortening rule table; and correcting the target pattern according to the initial correction value and the optical proximity effect correction model.