Edge Field Alignment in Nano-Imprinting Lithography
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current nano-fabrication techniques, such as imprint lithography, face challenges in achieving precise alignment between templates and substrates, particularly at the edges, leading to alignment errors and decreased die yield due to limited placement of alignment marks outside the substrate area.
Innovation Solution
A reconfigurable alignment system that includes multiple alignment measurement units capable of detecting alignment marks within sub-fields and potentially yielding dies, allowing for precise alignment and pattern transfer by repositioning alignment measurement units to capture marks within sub-fields and using independent theta measurement units for accurate spatial alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If alignment marks are placed outside the substrate area, then alignment precision is improved, but the area available for productive patterning is reduced
Solution Approach 1:
The patent places alignment marks in the vertical dimension (outside the substrate surface plane) rather than consuming horizontal substrate area. The marks are positioned on the substrate edge or in the space above/below the substrate, allowing optical access from the imaging system while preserving the entire substrate surface for productive patterning.
Solution Approach 2:
The patent introduces an intermediary optical system (imaging system with objective lens) that can detect alignment marks through the template or from the substrate edge. This intermediary allows alignment measurement without requiring physical contact or additional substrate area, as the imaging system acts as a mediator between the alignment marks and the control system.
2Measurement precision
If multiple alignment measurement units are added to detect marks within sub-fields, then alignment precision is improved, but device complexity increases
Solution Approach 1:
The imaging system is designed with multi-functionality, serving both as a template imaging system and an alignment measurement system. The same objective lens and detector are used to image both the template features and the alignment marks, eliminating the need for separate dedicated alignment measurement devices and reducing overall system complexity.
Solution Approach 2:
The system dynamically reconfigures the imaging system between template imaging mode and alignment measurement mode. The imaging system can be repositioned or reconfigured to detect alignment marks at different locations (within sub-fields or at substrate edges) as needed, providing flexibility without requiring permanent additional hardware for each measurement function.
3Reliability
If alignment marks are placed at substrate edges, then alignment coverage is improved, but alignment errors increase due to edge effects
Solution Approach 1:
The patent replaces mechanical alignment methods (physical contact or proximity-based alignment) with optical imaging methods. The alignment marks are detected through non-contact optical imaging, allowing marks to be placed at substrate edges without suffering from mechanical edge effects. The optical system can detect marks through the template or from the substrate edge plane without physical interference.
Data Source
AI summary
Systems and methods for alignment of template and substrate at the edge of substrate are described.