Backside Air Gap Design for Reduced Stray Capacitance
Here’s PatSnap Eureka !
Summary
Problems
As semiconductor technology advances to smaller geometries, stray capacitance between metal features on the backside of a wafer increases, posing challenges for reducing switching speed, power consumption, and coupling noise in semiconductor devices.
Innovation solutions
The introduction of air gaps in the backside dielectric layers between conductors on the wafer reduces stray capacitance by increasing isolation, achieved through a method involving the formation of trenches, metal plugs, and a dielectric liner with an over-hang profile, which creates an air gap surrounded by the dielectric liner.
TRIZ Analysis
Specific contradictions:
General conflict description:
Principle concept:
If semiconductor technology scales down to smaller geometries, then production efficiency increases and costs decrease, but stray capacitance between metal features increases
Why choose this principle:
The patent introduces air gaps (porous structure) in the backside dielectric layer to reduce stray capacitance. The air gaps create regions with lower dielectric constant (k≈1) compared to solid dielectric materials, thereby reducing the capacitive coupling between metal features while maintaining the scaled-down geometry benefits
Principle concept:
If semiconductor technology scales down to smaller geometries, then production efficiency increases and costs decrease, but stray capacitance between metal features increases
Why choose this principle:
The patent addresses the stray capacitance problem by utilizing the backside dimension of the wafer. By forming air gaps and conductive structures on the backside, the invention creates a third dimension for capacitance management, allowing reduction of parasitic effects without compromising the frontside circuit density
Application Domain
Data Source
AI summary:
The introduction of air gaps in the backside dielectric layers between conductors on the wafer reduces stray capacitance by increasing isolation, achieved through a method involving the formation of trenches, metal plugs, and a dielectric liner with an over-hang profile, which creates an air gap surrounded by the dielectric liner.
Abstract
A semiconductor structure has a frontside and a backside. The semiconductor structure includes an isolation structure at the backside; one or more transistors at the frontside, wherein the one or more transistors have source/drain epitaxial features; two metal plugs through the isolation structure and contacting two of the source/drain electrodes from the backside; and a dielectric liner filling a space between the two metal plugs, wherein the dielectric liner partially or fully surrounds an air gap between the two metal plugs.