FinFET Diffusion Break Structure for Self-Aligned Isolation
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Solution Overview
Problem
Existing semiconductor devices face challenges in integrating three-dimensional nanostructures, particularly in forming effective isolation between adjacent transistors, which affects processing complexity and manufacturing efficiency.
Innovation Solution
A self-aligned etching process is employed to form an isolation gate in FinFET devices using the interlayer dielectric layer and spacer sidewalls as etching mask elements, followed by depositing material layers to create a V-shaped trench and isolation gate for electrical separation of adjacent circuits, enhancing electrical isolation without requiring advanced lithography tools.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a three dimensional transistor structure is introduced to replace planar transistor, then functional density is improved, but processing complexity increases
Solution Approach 1:
The patent applies preliminary action by forming the isolation gate structure before final transistor fabrication steps. The isolation gate is created using self-aligned etching that utilizes existing interlayer dielectric and spacer sidewalls as masks, establishing the isolation framework in advance to guide subsequent processing steps and reduce overall complexity
Solution Approach 2:
The patent implements self-service through self-aligned etching where the interlayer dielectric layer and spacer sidewalls automatically serve as etching mask elements. This eliminates the need for separate mask alignment steps and advanced lithography tools, allowing the structure to define its own isolation regions without additional complex processing
2Manufacturing precision
If self-aligned etching process is used to form isolation gate, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The self-aligned etching process uses the interlayer dielectric and spacer sidewalls to automatically define the isolation gate boundaries. The existing structures serve as their own masks, eliminating the need for separate photolithography alignment steps and achieving high precision without additional complex equipment
Solution Approach 2:
The interlayer dielectric layer and spacer sidewalls perform multiple functions: they serve as structural support, define geometric boundaries, and simultaneously act as etching mask elements. This multi-functionality reduces the need for dedicated mask layers and simplifies the overall process while maintaining precision
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 method improves electrical isolation, reduces processing complexity, and enhances device stability, speed, and reliability by providing uniformity control over source/drain regions and fin-end allocation, all while avoiding additional costs or area penalties.
Implementation Method 1
A self-aligned etching process is employed to form an isolation gate in FinFET devices using the interlayer dielectric layer and spacer sidewalls as etching mask elements
Implementation Method 2
followed by depositing material layers to create a V-shaped trench and isolation gate for electrical separation of adjacent circuits
Data Source
AI summary
The present disclosure provides a semiconductor structure comprising one or more fins formed on a substrate and extending along a first direction; one or more gates formed on the one or more fins and extending along a second direction substantially perpendicular to the first direction, the one or more gates including an first isolation gate and at least one functional gate; source/drain features formed on two sides of each of the one or more gates; an interlayer dielectric (ILD) layer formed on the source/drain features and forming a coplanar top surface with the first isolation gate. A first height of the first isolation gate is greater than a second height of each of the at least one functional gate.