Combined Inline and On-Tool Metrology for Overlay Alignment
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Solution Overview
Problem
Existing digital lithography systems face challenges in achieving accurate overlay alignment and die placement for subsequent layers on substrates, particularly in semiconductor and display device manufacturing, necessitating improved systems and methods for enhancing alignment resolution and digital correction.
Innovation Solution
A combination of inline metrology and on-tool metrology systems is employed to measure and correct alignment, utilizing global alignment marks, die marks, and mini-marks to determine correction factors, enabling precise patterning through digital correction masks and image projection systems.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If traditional alignment methods are used, then the system is simpler to operate, but overlay accuracy deteriorates
Solution Approach 1:
The alignment system is segmented into two distinct components: inline metrology for measuring substrate and die mark positions, and on-tool metrology for measuring alignment mark positions during lithography. This segmentation allows each component to specialize in specific measurement tasks, achieving high overlay accuracy (improving manufacturing precision) while maintaining manageable system complexity through modular architecture
Solution Approach 2:
Alignment marks serve as intermediaries between the substrate coordinate system and the lithography tool coordinate system. These marks enable transformation and correlation of coordinates between different reference frames, facilitating precise overlay alignment without requiring direct complex measurements between all components
2Measurement precision
If comprehensive metrology data is captured, then alignment precision improves, but time consumption increases
Solution Approach 1:
Inline metrology performs preliminary measurement of substrate and die mark positions before the lithography process. This preliminary action captures essential alignment data in advance, allowing the on-tool metrology to focus only on alignment marks during lithography, thereby maintaining high alignment precision while reducing total measurement time
Solution Approach 2:
The system establishes continuous coordinate transformation relationships between inline and on-tool metrology through alignment marks. This continuity allows seamless integration of measurement data from both systems without requiring repeated measurements, maintaining precision while minimizing time loss
Data Source
AI summary
Aspects of the present disclosure generally relate to a digital lithography system and methods for alignment resolution with the digital lithography system. The digital lithography system includes a metrology system configured to improve overlay alignment for different layers of the lithography process. The metrology system includes an inline metrology system (IMS) in combination with an on tool metrology system (OTM), which enable substrate overlay alignment and die placement correction. The inline metrology system may be positioned on an inline metrology tool and the on tool metrology system is positioned on a digital lithography tool. The inline metrology system facilitates measurement of high-throughput measurement inline metrology data for marks such as die marks and global alignment marks for verification of process stability and die placement data for digital data correction. This inline metrology data can be compared with a design file to determine offsets for the digital data correction.