OPC Mask Layout Adjustment for MRC-Compliant Pattern Spacing
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Solution Overview
Problem
Existing mask manufacturing methods face challenges in improving the margin between patterns and critical dimension (CD) targeting due to optical proximity effects during the photolithography process.
Innovation Solution
An optical proximity correction (OPC) method that classifies neighboring patterns into groups based on their spatial relationships and selectively removes portions of patterns that do not comply with mask rule checks (MRC), optimizing the layout to meet MRC requirements while minimizing unnecessary corrections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If a first OPC is performed on a target design layout to obtain a first OPCed design layout, then optical proximity effects are corrected, but the interval between neighboring patterns may not comply with mask rule check (MRC)
Solution Approach 1:
The patent segments the correction process into multiple stages: first OPC to correct optical proximity effects, then a second OPC to adjust pattern intervals for MRC compliance. This segmentation allows each stage to address specific requirements independently, resolving the contradiction between optical correction and rule compliance.
Solution Approach 2:
The patent performs a preliminary check of pattern intervals after the first OPC and before final mask manufacturing. This preliminary action identifies patterns that do not comply with MRC, allowing for targeted second OPC corrections only where needed, rather than redesigning the entire layout.
2Reliability
If portions of patterns are removed to comply with MRC, then mask rule check compliance is improved, but the margin between patterns and critical dimension targeting may deteriorate
Solution Approach 1:
The patent applies local quality by performing the second OPC selectively only on patterns that do not comply with MRC, rather than uniformly adjusting all patterns. This localized correction maintains the original design intent and critical dimensions for compliant patterns while fixing only the non-compliant ones.
Solution Approach 2:
The patent changes geometric parameters (pattern intervals, margins, critical dimensions) during the second OPC to achieve MRC compliance. By carefully adjusting these parameters only where necessary, the method maintains optimal critical dimension targeting while ensuring rule compliance.
3Reliability
If a second OPC is performed to adjust pattern intervals for MRC compliance, then mask rule check compliance is improved, but the manufacturing process complexity increases
Solution Approach 1:
The patent segments the overall OPC process into two distinct stages: first OPC for optical proximity correction and second OPC for MRC compliance. This segmentation makes the complex process more manageable and allows each stage to be optimized independently, reducing overall process complexity.
Solution Approach 2:
The patent implements a feedback mechanism where the results of the first OPC are evaluated against MRC requirements, and only patterns failing the check undergo second OPC. This feedback-based approach prevents unnecessary processing of already-compliant patterns, reducing overall process complexity.
Data Source
AI summary
An optical proximity correction (OPC) method according to an embodiment may include obtaining a first OPCed design layout by performing a first OPC on a target design layout; identifying whether an interval between neighboring patterns in the first OPCed design layout complies with a mask rule check (MRC); and removing a portion of patterns, among the neighboring patterns, that are determined to not comply with the MRC, such that a distance between the patterns complies with the MRC after the portion is removed.