FinFET Fabrication via Mandrel Segmentation and Spacer Protection
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Solution Overview
Problem
Existing FinFET devices and fabrication methods lack flexibility in forming fin and isolation structures, leading to inefficiencies in processing and manufacturing complexity.
Innovation Solution
A method for fabricating FinFET devices involving the formation of mandrel features, coarse and fine cuts, and self-aligned isolation trenches, with a spacer layer protecting the fins during trench formation, allowing for improved fin uniformity and integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional FinFET fabrication methods are used, then fin structures can be formed, but flexibility in forming fin and isolation structures is limited
Solution Approach 1:
The fabrication process is divided into distinct stages: forming mandrel features, performing coarse cuts to create coarse spaces, performing fine cuts to create end-to-end spaces, and forming isolation trenches. This segmentation allows independent optimization of fin formation and isolation structure formation, providing flexibility while managing complexity through systematic process breakdown
Solution Approach 2:
Mandrel features are formed in advance before the actual fin and isolation structure formation. These mandrels serve as preliminary structures that guide subsequent etching processes, enabling flexible configuration of fins and isolation regions without increasing overall process complexity
2Reliability
If isolation trenches are formed without protection, then trench formation is simpler, but fin integrity is compromised
Solution Approach 1:
A spacer layer is introduced as an intermediary protective element during isolation trench formation. This spacer layer is deposited to cover the fins and is selectively removed after trench formation, allowing trenches to be formed with reduced complexity while maintaining fin integrity through the protective intermediary layer
Solution Approach 2:
The spacer layer is deposited in advance before isolation trench formation to protect the fins. This preliminary protective action ensures fin integrity is maintained during the trench etching process without requiring complex in-situ protection mechanisms
3Productivity
If scaling down is continued, then production efficiency increases and costs decrease, but processing complexity increases
Solution Approach 1:
The fabrication process is divided into distinct stages: forming mandrel features, performing coarse cuts to create coarse spaces, performing fine cuts to create end-to-end spaces, and forming isolation trenches. This segmentation allows independent optimization of fin formation and isolation structure formation, providing flexibility while managing complexity through systematic process breakdown
Solution Approach 2:
The spacer layer automatically forms around the fins through conformal deposition, providing self-aligned protection during trench formation. This self-service mechanism eliminates the need for additional alignment steps and complex process control, maintaining productivity while managing complexity at scaled dimensions
Data Source
AI summary
A method of fabricating a fin-like field-effect transistor (FinFET) device is disclosed. The method includes forming a mandrel features over a substrate, the mandrel feature and performing a coarse cut to remove one or more mandrel features to form a coarse space. After the coarse cut, the substrate is etched by using the mandrel features, with the coarse space as an etch mask, to form fins. A spacer layer is deposited to fully fill in a space between adjacent fins and cover sidewalls of the fins adjacent to the coarse space. The spacer layer is etched to form sidewall spacers on the fins adjacent to the coarse space. A fine cut is performed to remove a portion of one or more mandrel features to form an end-to-end space. An isolation trench is formed in the end-to-end space and the coarse space.