Sub-Resolution Assist Features for Lithographic Break Control
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Solution Overview
Problem
Conventional optical lithography technologies face challenges in achieving precise sub-wavelength feature dimensions and geometries due to limitations in Resolution Enhancement Technology (RET) and Optical Proximity Correction (OPC), particularly in designs with limited spacing between features, leading to issues like line end shortening and pitch problems.
Innovation Solution
The implementation of sub-resolution assist features (SRAF) that create controlled breaks between features, allowing for optimized placement and configuration of bridging features to enhance lithographic printing accuracy and reduce line end spacing, thereby facilitating multi-mask/exposure techniques and Double Patterning Technology (DPT) without requiring new equipment or design restrictions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If conventional optical lithography is used to pattern sub-wavelength features, then manufacturing process is simple, but manufacturing precision deteriorates due to line end shortening and pitch problems
Solution Approach 1:
The patent introduces bridging features as intermediary elements between adjacent features. These bridging features act as mediators that control the lithographic printing process to achieve precise feature dimensions and spacing. The bridging features are strategically placed to prevent line end shortening and control pitch, thereby improving manufacturing precision without requiring fundamentally new lithography equipment or processes.
2Productivity
If feature spacing is reduced to increase density, then productivity improves, but manufacturing precision deteriorates due to loss of control over line end spacing
Solution Approach 1:
The patent applies preliminary action by pre-calculating and pre-positioning bridging features in the layout design phase. These bridging features are strategically placed before lithography to anticipate and prevent line end shortening and spacing control issues. By performing this corrective action in advance during design, the patent enables reduced feature spacing while maintaining precise line end spacing control during manufacturing.
3Manufacturing precision
If multiple masks and exposures are used to achieve precise patterning, then manufacturing precision improves, but productivity deteriorates due to increased process steps
Solution Approach 1:
The patent extracts the precision control function from complex multi-mask processes and consolidates it into a single-mask approach using bridging features. By taking out the essential function of precise feature dimension and spacing control and implementing it through strategically placed bridging features on a single mask, the patent eliminates the need for multiple masks and exposures, thereby maintaining manufacturing precision while significantly improving productivity and manufacturing throughput.
Data Source
AI summary
Disclosed is a method, system, and computer program product for implementing controlled breaks using sub-resolution assist features. Sub-resolution bridging features are added to implement controlled breaks between features on the layout. The bridging features may also be used to facilitate or optimize multiple mask/exposure techniques that split a layout or features on a layout to address pitch problems.