Backside Power Rail Air Spacers for Lower Interconnect Coupling
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Solution Overview
Problem
As the minimum feature sizes in semiconductor devices decrease, issues such as increased capacitive coupling between conductive lines arise, limiting device speed and integration density.
Innovation Solution
The formation of air spacers in the backside interconnect structure adjacent to conductive lines, which are routed for power supply and ground lines, provides improved isolation by reducing capacitive coupling and allowing for increased device speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If minimum feature sizes are reduced to increase integration density, then more components can be integrated into a given area, but capacitive coupling between conductive lines increases
Solution Approach 1:
Air spacers are introduced as intermediary structures between adjacent conductive lines in the backside interconnect layer. These spacers create physical separation and reduce the electric field coupling between power supply lines and ground lines, thereby reducing capacitive coupling while allowing continued miniaturization for high integration density
Solution Approach 2:
The patent applies air spacers selectively at specific locations where capacitive coupling is most problematic - between adjacent power supply and ground lines in the backside interconnect structure. This localized approach reduces harmful coupling effects without requiring global increases in feature sizes, maintaining high integration density in non-critical areas
2Quantity of substance
If conductive lines are placed closer together to increase integration density, then more components can be integrated, but device speed decreases due to increased capacitive coupling
Solution Approach 1:
Air spacers serve as intermediary structures that enable closer spacing of conductive lines while maintaining acceptable signal speeds. By reducing capacitive coupling through physical separation, the spacers allow the interconnect structure to support higher frequency operations despite increased line density
Solution Approach 2:
The patent modifies the physical parameters of the interconnect structure by introducing air gaps with different dielectric properties compared to traditional solid dielectric materials. This parameter change reduces the capacitance between adjacent lines, enabling faster signal propagation while maintaining high integration density
Data Source
AI summary
Semiconductor devices including air spacers formed in a backside interconnect structure and methods of forming the same are disclosed. In an embodiment, a device includes a first transistor structure; a front-side interconnect structure on a front-side of the first transistor structure; and a backside interconnect structure on a backside of the first transistor structure, the backside interconnect structure including a first dielectric layer on the backside of the first transistor structure; a first via extending through the first dielectric layer, the first via being electrically coupled to a first source/drain region of the first transistor structure; a first conductive line electrically coupled to the first via; and an air spacer adjacent the first conductive line, the first conductive line defining a first side boundary of the air spacer.