Lithography Control Parameters for Edge Placement Error Reduction
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Solution Overview
Problem
Current semiconductor manufacturing processes face challenges in accurately reproducing patterns with dimensions smaller than the classical resolution limit of lithographic projection apparatuses, leading to difficulties in achieving desired electrical functionality and performance due to edge placement errors and stochastic variations.
Innovation Solution
A method is developed to determine control parameters for lithographic processes by calculating image-related metrics, such as edge placement error, from substrate images, and adjusting parameters to minimize these errors, thereby improving pattern reproduction accuracy and reducing stochastic variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If lithographic projection apparatuses are used to manufacture patterns with dimensions smaller than the classical resolution limit, then the manufacturing precision deteriorates due to edge placement errors and stochastic variations
Solution Approach 1:
The patent implements a feedback mechanism where measured edge placement errors from substrate images are used to determine and adjust control parameters of the lithographic process. The system calculates image-related metrics including EPE from obtained substrate images, then uses these metrics to determine control parameters that minimize EPE in subsequent manufacturing cycles, creating a closed-loop feedback system that continuously improves pattern reproduction accuracy
Solution Approach 2:
The patent changes control parameters of the lithographic process based on measured EPE values. By adjusting parameters such as focus, exposure dose, and illumination conditions according to the calculated image-related metrics, the system optimizes the lithographic process to minimize edge placement errors and improve pattern fidelity at dimensions below the classical resolution limit
2Productivity
If control parameters are not optimized, then manufacturing efficiency is reduced due to repeated manufacturing cycles required to achieve desired performance
Solution Approach 1:
The feedback loop enables single-pass or reduced-cycle manufacturing by using EPE measurements from previous cycles to pre-optimize control parameters for subsequent cycles. This reduces the need for repeated manufacturing cycles while maintaining or improving pattern accuracy, thereby increasing manufacturing efficiency
Solution Approach 2:
The system performs preliminary optimization of control parameters by calculating image-related metrics and determining optimal parameters before the actual lithographic manufacturing step. This preliminary action ensures that subsequent manufacturing cycles operate at optimal settings, reducing the need for rework and improving overall productivity
Data Source
AI summary
A method including: obtaining an image of at least part of a substrate, wherein the image includes at least one feature of a device being manufactured in a layer on the substrate; obtaining a layout of features associated with a previous layer adjacent to the layer on the substrate; calculating one or more image-related metrics in dependence on: 1) a contour determined from the image including the at least one feature and 2) the layout; and determining one or more control parameters of a lithographic apparatus and/or one or more further processes in a manufacturing process of the device in dependence on the one or more image-related metrics, wherein at least one of the control parameters is determined to modify the geometry of the contour in order to improve the one or more image-related metrics.