Air-Gap Trench Isolation for Integrated Circuit Parasitic Coupling
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Solution Overview
Problem
As integrated circuits shrink in size, effective isolation of working components becomes increasingly difficult, particularly in transistor structures, leading to issues like parasitic coupling and high power consumption.
Innovation Solution
The method involves forming a vent via through a shallow trench isolation (STI) into a substrate, selectively removing an exposed portion to create an opening, and sealing it to form an air gap within the substrate, which helps in reducing parasitic coupling and power consumption by creating an effective isolation region.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If integrated circuits are reduced in size, then device scaling is achieved, but effective isolation of working components becomes difficult leading to parasitic coupling and high power consumption
Solution Approach 1:
The substrate is segmented into isolated regions by creating air gap trenches that physically divide adjacent transistor structures. This segmentation prevents parasitic coupling between neighboring components while maintaining compact device dimensions, directly resolving the contradiction between size reduction and isolation effectiveness.
Solution Approach 2:
Material is extracted from between transistor structures to form air gap trenches filled with low-dielectric-constant material or void space. This extraction creates effective isolation regions that reduce parasitic coupling, allowing continued scaling without sacrificing isolation performance.
2Reliability
If traditional trench isolation is used, then component isolation is achieved, but device size reduction is limited
Solution Approach 1:
The dielectric constant parameter is changed by filling trenches with low-k material or leaving them as air gaps instead of using traditional silicon dioxide isolation. This parameter change achieves effective isolation with reduced trench dimensions, enabling further device size reduction while maintaining isolation effectiveness.
Data Source
AI summary
A method of forming an integrated circuit structure includes: forming a vent via extending through a shallow trench isolation (STI) and into a substrate; selectively removing an exposed portion of the substrate at a bottom of the vent via to form an opening within the substrate, wherein the opening within the substrate abuts at least one of a bottom surface or a sidewall of the STI; and sealing the vent via to form an air gap in the opening within the substrate.