Contact-Level Air Gap in Interlayer Dielectrics
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Solution Overview
Problem
Semiconductor devices exhibit high parasitic capacitances due to contact-level interlayer dielectrics, leading to increased power consumption and decreased device performance, which existing techniques have not adequately addressed.
Innovation Solution
A semiconductor structure with a contact-level air gap within the interlayer dielectrics is introduced, utilizing a self-assembly approach to form an air gap within the second dielectric layer extending vertically from the first to the third dielectric layer, reducing parasitic capacitances by incorporating a dielectric layer with a dielectric constant of approximately 1.0.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If contact-level interlayer dielectrics are formed using conventional dielectric materials (SiO2, Si3N4), then structural integrity and electrical insulation are achieved, but parasitic capacitances increase leading to higher power consumption and reduced device performance
Solution Approach 1:
The patent changes the dielectric constant parameter of the interlayer dielectric material by introducing an air gap (dielectric constant ≈ 1.0) within the second dielectric layer. This parameter change directly reduces parasitic capacitances between contacts and between contacts and diffusion regions, thereby reducing power consumption without compromising structural integrity or electrical insulation
Solution Approach 2:
The patent creates a composite dielectric structure consisting of multiple dielectric layers (first dielectric layer, second dielectric layer with air gap, third dielectric layer) with different dielectric constants. This composite structure combines the benefits of solid dielectric materials (structural support, insulation) with air (low dielectric constant, low capacitance) to achieve reduced parasitic capacitance while maintaining overall structural integrity
2Reliability
If air gap is introduced within the second dielectric layer to reduce parasitic capacitances, then power consumption decreases and device performance improves, but manufacturing complexity increases
Solution Approach 1:
The patent employs self-aligned processes where the air gap is positioned automatically through conformal deposition of dielectric layers around contact structures. The first dielectric layer conformally covers the contact structures, and the air gap forms within the second dielectric layer aligned above the semiconductor device, eliminating the need for separate alignment and positioning steps that would increase manufacturing complexity
Solution Approach 2:
The patent performs preliminary formation of contact structures and conformal dielectric layers before creating the air gap. By pre-establishing the contact structures and depositing dielectric layers in a self-aligned manner, the air gap positioning is predetermined, simplifying the overall manufacturing process despite the added complexity of air gap formation
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 air gap significantly minimizes parasitic capacitances such as contact-to-contact and gate-to-diffusion region capacitances, thereby reducing power consumption and enhancing device performance by exposing portions of contacts within the air gap, while maintaining structural integrity for back-end-of-line wiring.
Implementation Method 1
reducing parasitic capacitances by incorporating a dielectric layer with a dielectric constant of approximately 1.0
Data Source
AI summary
Disclosed are embodiments of a semiconductor structure having a contact-level air gap within the interlayer dielectrics above a semiconductor device in order to minimize parasitic capacitances (e.g., contact-to-contact capacitance, contact-to-diffusion region capacitance, gate-to-contact capacitance, gate-to-diffusion region capacitance, etc.). Specifically, the structure can comprise a semiconductor device on a substrate and at least three dielectric layers stacked above the semiconductor device. An air gap is positioned with the second dielectric layer aligned above the semiconductor device and extending vertically from the first dielectric layer to the third dielectric layer. Also disclosed are embodiments of a method of forming such a semiconductor structure using a self-assembly approach.