Air Spacer Interconnect Structure for Low-Crosstalk Semiconductor Wiring
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Solution Overview
Problem
As semiconductor devices become smaller, the pitch between metal wires on the same dielectric layer becomes smaller, leading to increased electromagnetic noise and crosstalk, which results in higher resistance-capacitance (RC) delay and degraded performance.
Innovation Solution
The introduction of air spacers formed between conductive wires by etching a dielectric layer and enclosing the gaps with an insulating capping layer, utilizing the low dielectric constant of air to reduce electromagnetic noise and crosstalk.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the pitch between metal wires is reduced to increase integration, then device functionality and integration are improved, but electromagnetic noise and crosstalk increase
Solution Approach 1:
Air spacers are introduced as intermediary structures between adjacent conductive wires. These air spacers act as mediators that reduce the electromagnetic coupling between wires by providing electrical isolation and reducing capacitance, thereby decreasing crosstalk and electromagnetic noise while allowing wires to remain in close proximity for high integration
Solution Approach 2:
The dielectric constant parameter is changed by replacing solid dielectric material with air (which has a dielectric constant of approximately 1.0) in the regions between conductive wires. This parameter change reduces the capacitance between adjacent wires, thereby reducing RC delay and electromagnetic noise while maintaining the small pitch required for high integration
2Productivity
If the pitch between metal wires is reduced to increase integration, then device functionality and integration are improved, but RC delay increases
Solution Approach 1:
The capacitance parameter is reduced by introducing air spacers between conductive wires. Since RC delay is directly proportional to capacitance, reducing the capacitance through air spacers (which have lower dielectric constant than solid dielectrics) decreases the RC delay, allowing faster signal propagation despite reduced wire pitch
Solution Approach 2:
Air spacers serve as intermediary structures that reduce the capacitive coupling between adjacent wires. By placing air (a material with minimal dielectric properties) between the wires, the capacitance is reduced, which directly reduces the RC delay and allows for faster signal transmission in highly integrated circuits
3Object-affected harmful factors
If air spacers are formed by etching dielectric layer and adding insulating capping layer, then electromagnetic noise and crosstalk are reduced, but device structure becomes more complex
Solution Approach 1:
The dielectric layer is segmented or selectively removed in specific regions between conductive wires to create air gaps. This segmentation approach allows air spacers to be formed only where needed for crosstalk reduction, rather than modifying the entire structure, thereby reducing complexity while maintaining effectiveness
Solution Approach 2:
The air spacers are formed using self-aligned processes where the insulating capping layer is deposited conformally on the conductive wires and then planarized. The air gaps are created as a byproduct of the etching process to expose the conductive wires, and the subsequent capping layer deposition automatically forms the spacer structure without requiring additional alignment steps, reducing process complexity
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
Significantly reduces electromagnetic noise and crosstalk between conductive wires, improving semiconductor device performance by minimizing RC delay and signal distortion.
Implementation Method 1
utilizing the low dielectric constant of air to reduce electromagnetic noise and crosstalk
Data Source
AI summary
A semiconductor device is provided, which includes a substrate, a first dielectric layer, a conductive layer, and an insulating capping layer. The first dielectric layer is disposed on the substrate. The conductive layer is disposed on the first dielectric layer. The conductive layer includes a plurality of conductive wires. The insulating capping layer is disposed on the conductive layer, and configured to enclose a plurality of first gaps between the conductive wires to form a plurality of air spacers.