Air Gap Isolation in Planarized Interlayer Dielectric
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Solution Overview
Problem
Highly integrated semiconductor devices face challenges in reducing parasitic capacitance between interconnections, leading to increased RC delay and reduced operational speed due to dense circuit topologies.
Innovation Solution
The introduction of air gaps between interconnections in a semiconductor device, achieved through a method involving the formation of a first and second insulating layer with different region spacings and etching processes, reduces dielectric constants and minimizes parasitic coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If air gaps are introduced between interconnections to reduce parasitic capacitance, then operating speed is improved, but device complexity increases
Solution Approach 1:
The patent introduces air gaps (porous structure) between interconnections by forming recessed regions in the interlayer dielectric and filling them with air instead of conventional dielectric material. This reduces the effective dielectric constant in high-density regions, thereby reducing parasitic capacitance and improving operating speed while managing the increased device complexity through targeted structural modification.
2Loss of time
If air gaps are introduced between interconnections to reduce parasitic capacitance, then RC delay is reduced, but manufacturing complexity increases
Solution Approach 1:
The patent applies local quality by forming air gaps selectively in high-density interconnection regions where parasitic capacitance is most problematic, rather than uniformly throughout the device. The recessed regions are created through targeted etching processes in specific areas, allowing RC delay reduction where needed while minimizing the impact on overall manufacturing complexity.
3Adaptability or versatility
If dense circuit topologies are used to achieve high integration, then functional capacity is increased, but parasitic capacitance between interconnections increases
Solution Approach 1:
The patent addresses the harmful effect of parasitic capacitance in dense circuit topologies by introducing air gaps between closely spaced interconnections. The porous structure created by air gaps reduces the effective dielectric constant in high-density regions, thereby reducing capacitive coupling and signal interference while maintaining the high functional capacity enabled by dense packaging.
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
This approach effectively reduces parasitic capacitance, enhancing the operating speed of semiconductor devices by creating air gaps that decrease dielectric constants between interconnections, thereby improving the reliability and performance of high-density chip stack structures.
Implementation Method 1
creating air gaps that decrease dielectric constants between interconnections
Data Source
AI summary
A semiconductor device includes an interlayer insulating layer including a first insulating layer on a substrate, and a plurality of interconnections in the first insulating layer. The interlayer insulating layer includes a first region, and a second region including an air gap. The air gap is defined between a pair of the interconnections in the second region. A top surface of the first insulating layer of the first region is lower than a top surface of at least one of the interconnections in the first region.