Aluminum Oxide Air-Gap Liners for Dense Interconnect Capacitance
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Solution Overview
Problem
High-aspect-ratio traces in semiconductor dies with high capacitance due to close proximity limit performance.
Innovation Solution
Introduce air gaps between neighboring traces filled with a low dielectric constant gas, such as air, to reduce capacitance and signal delay, using a sacrificial material deposition and aluminum oxide liners to maintain structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If high-aspect-ratio traces are placed close together to increase interconnect density, then resistance is reduced, but capacitance increases and limits performance
Solution Approach 1:
A liner layer is introduced as an intermediary between adjacent traces. This liner acts as a barrier that prevents direct interaction between the traces and the dielectric material, thereby reducing stress-induced leakage current and capacitance effects while maintaining the high-density interconnect structure
Solution Approach 2:
The dielectric constant parameter is changed by replacing traditional dielectric materials with air gaps between traces. This parameter change directly reduces capacitance between closely-spaced traces while maintaining the high interconnect density achieved through high-aspect-ratio structures
2Object-generated harmful factors
If air gaps are introduced between traces to reduce capacitance, then signal integrity improves, but structural integrity may be compromised
Solution Approach 1:
The liner serves as a structural intermediary that bridges the gap between traces. It provides mechanical support and maintains structural integrity while allowing the air gap to exist, thus preventing collapse or deformation of the high-aspect-ratio traces
Solution Approach 2:
The liner is implemented as a thin film structure that provides sufficient mechanical strength to maintain trace integrity while being thin enough to minimize capacitance. The thin film acts as a flexible barrier that accommodates the air gap without compromising overall structure
3Strength
If traditional dielectric materials are used between traces, then structural support is maintained, but capacitance and stress-induced leakage current increase
Solution Approach 1:
The dielectric material is extracted or removed from between the traces, replacing it with air gaps. This extraction eliminates the source of stress-induced leakage current and capacitance problems associated with traditional dielectric materials while the liner provides necessary structural support
Solution Approach 2:
Air is used as an inert environment between traces instead of traditional dielectric materials. The air gap provides electrical isolation without introducing stress-induced leakage current or high capacitance effects, while the liner maintains structural integrity
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
Reduces capacitance and signal delay, improving signal integrity and overall performance by lowering the dielectric constant between traces.
Implementation Method 1
Aluminum oxide may avoid issues from stress-induced leakage current (SILC) that may result when using silicon oxide or other materials
Implementation Method 2
part of the volume between neighboring traces is filled with air, rather than another material with a higher dielectric constant
Data Source
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AI summary
Technologies for air gaps in semiconductor dies with aluminum oxide liners are disclosed. In an illustrative embodiment, high-aspect-ratio traces on an interconnect layer of a semiconductor die have a relatively narrow pitch. In order to reduce the capacitance between neighboring traces, an air gap is present. A liner above the air gap prevents the air gap from being filled during the semiconductor processing. In an illustrative embodiment, the liner is aluminum oxide, which may prevent stress induced leakage current (SILC) that may result when using silicon oxide or other materials.