Hybrid Fin Structure With Air Gap for Lower FinFET Capacitance
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Solution Overview
Problem
Existing semiconductor manufacturing processes face challenges in achieving desired density and performance in FinFET devices due to increased complexity and capacitance between adjacent conductive features, affecting device performance and operating speed.
Innovation Solution
The introduction of a method to fabricate semiconductor devices with a hybrid fin structure that includes dielectric fins and an air gap formed by removing a dummy spacer layer, which reduces capacitance and enhances gate control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional IC manufacturing processes are used for scaling, then manufacturing complexity increases, but device density and performance improvement is limited
Solution Approach 1:
The patent segments the fin structure into hybrid fins with different dielectric materials (high-k and low-k) and introduces air gaps to divide the continuous dielectric region. This segmentation reduces capacitance between adjacent conductive features while maintaining manufacturing compatibility through sequential processing steps including selective etching and dielectric deposition.
Solution Approach 2:
The patent applies local quality by using different dielectric materials (high-k and low-k) in specific regions of the fin structure. High-k dielectric is used in certain fin regions to enhance gate control, while low-k dielectric and air gaps are introduced in other regions to reduce capacitance. This localized material differentiation optimizes both device performance and manufacturing efficiency.
2Productivity
If device dimensions are scaled down, then production efficiency improves and costs decrease, but capacitance between adjacent conductive features increases
Solution Approach 1:
The patent extracts the harmful dielectric material and replaces it with air gaps in specific regions between adjacent conductive features. By removing the continuous dielectric and introducing air regions with lower permittivity, the capacitance between conductive features is reduced, thereby improving device performance while maintaining scaled dimensions for high production efficiency.
3Reliability
If FinFET devices are used to improve gate control, then short-channel effects are reduced, but capacitance between adjacent features affects operating speed
Solution Approach 1:
The patent employs composite materials by combining high-k dielectric, low-k dielectric, and air gap regions within the hybrid fin structure. The high-k dielectric enhances gate control and reduces short-channel effects, while the low-k dielectric and air gaps reduce parasitic capacitance between adjacent conductive features. This composite structure simultaneously improves both reliability and operating speed.
Data Source
AI summary
Methods and devices that provide for a fin structure and a dielectric fin structure. A gate structure is formed over the fin structure and the hybrid fin structure. A plurality of dielectric layers is adjacent the gate structure and over the hybrid fin structure between the gate structure and a contact element over the dielectric fin structure. The plurality of dielectric layers includes an air gap, formed by removal of a dummy spacer layer.