Ferroelectric FinFET Gate Stack With Self-Aligned Fin Patterning
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Solution Overview
Problem
The challenge in semiconductor manufacturing lies in achieving efficient and precise patterning of fins for FinFET devices to enhance electrical control over the channel, particularly as devices scale down in size.
Innovation Solution
A method involving photolithography and self-aligned processes is used to pattern fins, followed by the formation of dummy gate structures and spacers, recessing the fins, and growing strained material structures to strain the fins, ultimately replacing the dummy gates with metal gate structures and integrating capacitor structures for improved performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If photolithography and self-aligned processes are used to pattern fins, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The fabrication process is divided into multiple self-aligned steps including forming mandrels, depositing spacer materials, and selective etching. Each step builds upon the previous one with automatic alignment, breaking down the complex fin patterning into manageable segments that collectively achieve high precision without requiring complex single-step processes
Solution Approach 2:
Dummy gate structures are formed preliminarily before the actual gate structure. These dummy gates serve as placeholders that guide subsequent processing steps, including spacer formation and fin recessing, ensuring precise alignment is achieved before final gate fabrication
2Reliability
If strained material structures are grown over semiconductor fins, then electrical control is improved, but manufacturing precision requirements increase
Solution Approach 1:
Strained material structures are grown selectively only in specific regions where fins are exposed, not across the entire substrate. The strain engineering is applied locally to the channel regions between source and drain, providing enhanced electrical control precisely where needed without affecting other device regions
Solution Approach 2:
The dummy gate structure serves as an intermediary element that defines the precise location where strained materials should be grown. By removing portions of the dummy gate to expose fins and then growing strained materials in these exposed regions, the dummy gate acts as a template ensuring accurate spatial positioning of the strain layers
3Reliability
If dummy gate structures are formed and later replaced with metal gate structures, then device performance is improved, but manufacturing time increases
Solution Approach 1:
Dummy gate structures are formed preliminarily to enable subsequent processing steps including spacer formation, fin recessing, and strained material growth. These dummy gates are removed and replaced with metal gates in a later step, allowing the fabrication process to proceed with simplified structures in place while maintaining the ability to achieve high-performance final devices
Solution Approach 2:
The dummy gate structure serves as a temporary intermediary that facilitates the fabrication of the final metal gate structure. It provides a placeholder that guides the formation of surrounding structures and is subsequently replaced with the high-performance metal gate, enabling complex device architecture to be built systematically
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enables precise fin patterning and strain engineering, enhancing electrical control and performance of FinFET devices, facilitating the integration of advanced semiconductor features.
Implementation Method 1
growing strained material structures to strain the fins
Data Source
AI summary
A semiconductor device includes a semiconductor fin, a gate structure, a capacitor structure, a conductive contact, and a hard mask layer. The gate structure is disposed across the semiconductor fin. The capacitor structure is disposed on the gate structure. The capacitor structure includes a ferroelectric layer. The conductive contact is disposed on the capacitor structure. The hard mask layer laterally surrounds the conductive contact. The conductive contact protrudes from a top surface of the hard mask layer.