Compressive Stressed Low-k Dielectric for Strain Engineering
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Solution Overview
Problem
In advanced semiconductor devices, the increasing dielectric constant of materials used for strain engineering techniques contributes to signal propagation delays, while traditional dielectric materials like silicon nitride may compromise performance due to high permittivity and parasitic capacitance.
Innovation Solution
A nitrogen, silicon, and carbon-containing dielectric layer is deposited with high compressive stress using plasma-assisted CVD, maintaining a low dielectric constant and providing etch stop and diffusion blocking capabilities, thereby replacing silicon nitride and reducing signal propagation delays.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If traditional dielectric materials like silicon nitride are used for strain engineering, then mechanical strength and diffusion blocking are improved, but dielectric constant increases causing signal propagation delays
Solution Approach 1:
The patent applies composite materials by combining silicon nitride (providing mechanical strength and diffusion blocking) with low-k dielectric materials (providing low permittivity). This composite structure maintains the mechanical integrity and protective functions while reducing the overall dielectric constant to minimize signal propagation delays and parasitic capacitance effects.
Solution Approach 2:
The patent implements local quality by applying silicon nitride selectively in specific regions where mechanical strength and diffusion blocking are critical (such as at interfaces and stress-inducing locations), while using low-k dielectric materials in regions where electrical performance is paramount. This localized material distribution optimizes both mechanical and electrical properties throughout the device structure.
2Loss of time
If low-k dielectric materials are used to reduce permittivity, then signal propagation delay is reduced, but mechanical stability and diffusion blocking capabilities deteriorate
Solution Approach 1:
The patent uses composite materials to combine the low permittivity benefits of low-k dielectric materials with the mechanical stability and diffusion blocking of silicon nitride. The composite structure ensures that neither material's weaknesses dominate, achieving both fast signal propagation and reliable mechanical protection.
Solution Approach 2:
The patent achieves multi-functionality by designing a dielectric system that simultaneously provides electrical insulation, mechanical support, diffusion blocking, and stress management. The combination of materials ensures that the structure performs multiple critical functions without requiring separate dedicated layers for each function, thereby maintaining reliability while reducing signal delay.
3Ease of manufacture
If silicon nitride is added as etch stop material, then etch resistance is improved, but overall permittivity of metallization system increases
Solution Approach 1:
The patent applies local quality by positioning thin silicon nitride etch stop layers only at specific interfaces where etching selectivity is required, rather than using silicon nitride throughout the entire dielectric stack. This minimizes the volume of high-permittivity material while maintaining sufficient etch resistance and process control.
Solution Approach 2:
The patent employs parameter changes by optimizing the thickness of silicon nitride etch stop layers to the minimum required for etch selectivity, and by adjusting the composition and properties of surrounding low-k dielectric materials to compensate for the localized permittivity increase, thereby maintaining overall low signal propagation delay.
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
The solution enables efficient strain engineering with reduced signal propagation delays and enhanced mechanical characteristics, maintaining compatibility with conventional device configurations and manufacturing schemes.
Implementation Method 1
A nitrogen, silicon, and carbon-containing dielectric layer is deposited with high compressive stress using plasma-assisted CVD
Implementation Method 2
A nitrogen, silicon, and carbon-containing dielectric layer is deposited with high compressive stress using plasma-assisted CVD
Implementation Method 3
the dielectric layer... has an internal stress level of approximately 1 GPa or higher of compressive stress
Implementation Method 4
inducing strain at the transistor and in particular in the channel region
Data Source
AI summary
A nitrogen-containing silicon carbide material may be deposited on the basis of a single frequency or mixed frequency deposition recipe with a high internal compressive stress level up to 1.6 GPa or higher. Thus, this dielectric material may be advantageously used in the contact level of sophisticated integrated circuits, thereby providing high strain levels while not unduly contributing to signal propagation delay.