Staggered Interconnect Lines for Capacitance Reduction
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Solution Overview
Problem
Interconnect structures using low-k interlayer dielectrics and air gaps face challenges in reducing line-to-line capacitance while maintaining patternability and mechanical stability, as the moderate-k etch stop material required for copper layers occupies space and reduces capacitance benefits.
Innovation Solution
The implementation of staggered interconnect lines with optional air gaps adjacent to each line to maximize reductions in line-to-line capacitance, where the interconnect lines are laterally offset, and air gaps are strategically placed to minimize capacitance without compromising integration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If low-k interlayer dielectrics and air gaps are used to reduce line-to-line capacitance, then interconnect performance is improved, but patternability and mechanical stability are reduced
Solution Approach 1:
The patent applies asymmetry by staggering the alignment of interconnect lines in adjacent layers, breaking the symmetric vertical alignment. This lateral offset creates asymmetric spacing between lines in different layers, reducing the overlapping area and thus the line-to-line capacitance while maintaining manufacturability through standard lithographic processes
2Loss of energy
If low-k interlayer dielectrics and air gaps are used to reduce line-to-line capacitance, then interconnect performance is improved, but mechanical stability is reduced
Solution Approach 1:
The patent employs composite materials by combining low-k dielectric material with air gaps in a hybrid structure. The low-k dielectric provides mechanical support and stability while the air gaps contribute to capacitance reduction. This composite approach allows the structure to benefit from both the mechanical properties of solid dielectric and the electrical properties of air
3Reliability
If moderate-k etch stop material is used to hermetically seal copper layers, then copper oxidation is prevented, but capacitance reduction benefit is reduced due to space occupation
Solution Approach 1:
The patent applies local quality by making the etch stop layer conformal and localized only where required for copper protection, rather than using a thick uniform layer. The etch stop material is deposited as a thin conformal coating that provides just enough protection against copper oxidation while minimizing the space it occupies, thereby preserving the capacitance reduction benefits of air gaps
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 line-to-line capacitance by optimizing the arrangement of staggered interconnect lines and air gaps, improving overall interconnect performance without sacrificing patternability or mechanical stability.
Implementation Method 1
reduce line-to-line capacitance as a means of improving overall performance
Implementation Method 2
Low-k interlayer dielectrics (ILDs) and air gaps are used between structures in various interconnect technologies
Data Source
AI summary
An interconnect structure is disclosed. The interconnect structure includes a first line of interconnects and a second line of interconnects. The first line of interconnects and the second line of interconnects are staggered. The individual interconnects of the second line of interconnects are laterally offset from individual interconnects of the first line of interconnects. A dielectric material is adjacent to at least a portion of the individual interconnects of at least one of the first line of interconnects and the second line of interconnects.