Modifying Merged Sub-Resolution Assist Features
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing techniques for modifying merged sub-resolution assist features (SRAFs) in photolithography are unsatisfactory, as they may print on the wafer or violate mask rules, leading to distortion and process margin issues.
Innovation Solution
Representing merged SRAFs by their axes allows for simplified modification, where the length and configuration of these axes determine the modification procedure, ensuring that the SRAFs are converted to avoid printing and adhere to design rules by adjusting their lengths and widths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If sub-resolution assist features (SRAFs) are added to compensate for optical diffraction distortions, then the process margin of the wafer pattern is improved, but the SRAFs may print on the wafer or violate mask rules
Solution Approach 1:
The patent segments merged SRAFs into individual SRAF components by identifying and processing each SRAF separately within the merged region. This allows independent modification of each SRAF's dimensions and position, enabling precise control to prevent printing while maintaining the collective benefit for process margin.
Solution Approach 2:
The patent modifies the dimensions (width and length) of SRAFs by adjusting their parameters within acceptable ranges. By changing these parameters, the SRAFs maintain their assist function for improving process margin while staying below the printing threshold and complying with mask rules.
2Reliability
If merged SRAFs are modified to prevent printing and comply with mask rules, then the reliability of the photolithographic process is improved, but the complexity of the modification procedure increases
Solution Approach 1:
The patent divides the complex task of modifying merged SRAFs into sequential steps: identifying merged SRAF regions, segmenting them into individual SRAFs, evaluating each SRAF's compliance status, and applying targeted modifications. This stepwise segmentation reduces the overall complexity by making each sub-task manageable and systematic.
Solution Approach 2:
The modification system automatically evaluates SRAF compliance and applies necessary adjustments without requiring manual intervention for each SRAF. The system self-regulates by comparing SRAF dimensions against mask rules and printing thresholds, then autonomously modifies parameters to ensure compliance, reducing procedural complexity.
Data Source
AI summary
Modifying merged sub-resolution assist features includes receiving a mask pattern comprising the merged sub-resolution assist features, where a segmenting sub-resolution assist feature intersects a segmented sub-resolution assist feature at an intersection. Each sub-resolution assist feature is represented by an axis of the sub-resolution assist feature. The length of at least one axis is established, and an axis is modified in accordance with the length. Each axis is converted to a sub-resolution assist feature to yield the modified merged sub-resolution assist features.