Mask Layout Assist Pattern Placement for Optical Proximity Correction
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Solution Overview
Problem
The optical proximity effect (OPE) occurs during the exposure process in semiconductor manufacturing, leading to challenges in forming precise patterns, and existing optical proximity correction (OPC) methods are inefficient in addressing these issues.
Innovation Solution
A mask layout design method that includes determining a forbidden area and designing an auxiliary pattern within this area, utilizing illumination system inversion, clustering, and aligning inverted pattern regions to mitigate OPE, thereby reducing the process dose and improving pattern precision.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If optical proximity correction (OPC) is applied to suppress optical proximity effect, then pattern precision is improved, but manufacturing complexity increases
Solution Approach 1:
The patent applies preliminary action by pre-calculating and pre-placing auxiliary patterns in the mask layout design stage. The forbidden area is determined in advance through illumination system inversion, and auxiliary patterns are designed and positioned before the actual manufacturing process. This preliminary preparation simplifies the overall manufacturing process by avoiding complex real-time corrections during exposure.
Solution Approach 2:
The patent introduces auxiliary patterns as intermediary elements between the main patterns. These auxiliary patterns act as mediators that compensate for optical proximity effects without directly modifying the main circuit patterns. The auxiliary patterns are placed in forbidden areas determined through illumination system inversion, serving as a buffer that simplifies the correction process while maintaining pattern precision.
2Manufacturing precision
If auxiliary patterns are added to reduce optical proximity effect, then pattern precision is improved, but process dose increases
Solution Approach 1:
The patent applies local quality by placing auxiliary patterns only in specific forbidden areas where optical proximity effects are most pronounced. The illumination system inversion process identifies these critical regions, and auxiliary patterns are strategically positioned only where needed, rather than uniformly across the entire mask. This localized approach reduces the overall process dose while maintaining pattern precision in affected areas.
Solution Approach 2:
The patent uses illumination system inversion to determine the forbidden area for auxiliary patterns. Instead of directly calculating which areas need correction, the method inverts the illumination system to identify regions where auxiliary patterns should be placed. This inversion approach optimizes the placement of auxiliary patterns to achieve the maximum correction effect with minimal additional dose.
3Measurement precision
If illumination system inversion is used to determine forbidden area, then auxiliary pattern placement precision is improved, but calculation complexity increases
Solution Approach 1:
The patent uses illumination system inversion as a computational model that copies and inverts the illumination characteristics. By creating an inverted representation of the illumination system, the method can determine forbidden areas through pattern recognition and alignment processes. This copying approach transforms a complex optimization problem into a more manageable pattern matching problem, improving placement precision while controlling calculation complexity.
Data Source
AI summary
Provided is a mask layout design method including receiving input data, calculating a forbidden area, and designing an assist pattern disposed within the forbidden area, wherein the calculating of the forbidden area is performed by inverting an illumination system.