Lithography Pattern Modification for Best Focus Alignment
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Solution Overview
Problem
The challenge in semiconductor integrated circuit (IC) manufacturing lies in forming reliable devices at smaller sizes due to increased complexity and difficulty in lithography processes, where regional topography and exposure conditions vary across the substrate, affecting pattern quality and process windows.
Innovation Solution
The solution involves obtaining regional information at different target portions of the substrate to determine individual best focus positions for patterns, and modifying the patterns or their assist features to ensure they are projected at these optimal focus positions during the lithography process, thereby ensuring high-quality pattern formation and expanding the process window.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If feature sizes continue to decrease to increase functional density, then production efficiency increases and costs lower, but fabrication process complexity and difficulty increase
Solution Approach 1:
The patent applies local quality by determining individual best focus positions for different target portions of the substrate based on regional topography and exposure conditions. Instead of using a single fixed focus position for the entire substrate, the method identifies optimal focus positions specific to each region, allowing patterns to be formed at the smallest feature sizes with high precision despite varying fabrication conditions across the substrate.
2Adaptability or versatility
If regional topography and exposure conditions vary across the substrate, then manufacturing flexibility is maintained, but pattern quality and process window deteriorate
Solution Approach 1:
The patent determines individual best focus positions for each target portion based on its specific regional topography and exposure conditions. This allows the system to adapt to varying manufacturing conditions while maintaining high pattern quality by optimizing focus position for each region rather than using a uniform approach.
Solution Approach 2:
The patent performs preliminary analysis of regional topography and exposure conditions before pattern formation. By obtaining regional information in advance and determining optimal focus positions beforehand, the system prepares compensation strategies that ensure high pattern quality even when regional variations occur during manufacturing.
3Ease of operation
If a single fixed focus position is used for the entire substrate, then the lithography process is simple to operate, but pattern formation quality deteriorates under varying regional conditions
Solution Approach 1:
The patent transitions from a static, fixed focus position approach to a dynamic focus position determination system. The system automatically determines optimal focus positions for each target portion based on real or pre-determined regional conditions, allowing the focus position to adapt dynamically to varying substrate characteristics while maintaining ease of operation through automated control.
Data Source
AI summary
A pattern modification method and a patterning process are provided. The method includes extracting a first pattern and a second pattern to be respectively transferred to a first target portion and a second target portion of a resist layer. The method also includes obtaining regional information of the first target portion and the second target portion. The method includes determining a first desired focus position for transferring the first pattern based on the regional information. In addition, the method includes determining a second desired focus position for transferring the second pattern based on the regional information. The method includes modifying one or both of the first pattern and the second pattern. As a result, focus positions of the first pattern and the second pattern are shifted to be substantially and respectively positioned at the first desired focus position and the second desired focus position during an exposure operation.