Semiconductor Interconnects With Linked Air Gaps
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Solution Overview
Problem
In semiconductor structures, the increasing miniaturization leads to significant signal propagation delays due to capacitance between conductive features, which is not adequately addressed by existing technologies.
Innovation Solution
The introduction of air gaps between conductive features in semiconductor structures, achieved through the formation of sacrificial place-holding features and their subsequent removal, reduces capacitance by creating inter-layer and intra-layer air gaps that connect conductive features across wire levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conductive features are placed closer together to increase integration density, then device miniaturization is achieved, but capacitance between conductive features increases causing signal propagation delays
Solution Approach 1:
Air gaps are introduced as intermediary spaces between conductive features (traces and vias) to reduce capacitive coupling. The air gaps act as mediators that physically separate conductive elements while maintaining electrical connectivity through vias, thereby reducing parasitic capacitance and signal propagation delays despite increased integration density
Solution Approach 2:
Air gaps are selectively positioned at specific locations where capacitive coupling is most problematic, such as between overlapping traces in different wire levels and between adjacent vias. This localized application of air gaps targets the most critical capacitance sources without requiring global restructuring of the interconnect architecture
2Speed
If air gaps are introduced between conductive features to reduce capacitance, then signal propagation speed is improved, but manufacturing complexity increases
Solution Approach 1:
Sacrificial place-holding features are formed in advance during the manufacturing process to define the precise locations and dimensions of future air gaps. These sacrificial structures are created before the final air gap formation, allowing for controlled removal to create air gaps with high precision and repeatability, thereby managing manufacturing complexity
Solution Approach 2:
Sacrificial place-holding features are temporarily introduced and then completely removed to create the air gaps. This extraction process transforms the manufacturing challenge of creating void spaces into a simpler process of removing pre-formed sacrificial material, enabling precise air gap formation while maintaining process control
Data Source
AI summary
A semiconductor structure comprises a first wire level, a second wire level and a via level. The first wire level comprises a first conductive feature. The second wire level is disposed on the first wire level. The second wire level comprises a second conductive feature and a third conductive feature. The via level is disposed between the first wire level and the second wire level. The via level comprises a via connecting the first conductive feature and the second conductive feature. There is a first air gap between the first conductive feature and the second conductive feature. There is a second air gap between the second conductive feature and the third conductive feature. The first air gap and the second air gap are linked.