Damascene Interconnect Air Gap for RC Delay Reduction
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Solution Overview
Problem
The RC delay in semiconductor interconnect structures, caused by resistance and capacitance, hinders signal propagation speed and power dissipation as device dimensions shrink, despite efforts to minimize resistance with copper interconnects.
Innovation Solution
A semiconductor device structure incorporating an etch barrier layer, dielectric layer, conductive metal interconnect, metal barrier layer, and air gaps formed within the dielectric layer to reduce permittivity, along with photosensitive passivation materials to manage the air gaps, effectively lowering capacitance and RC delay.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper interconnects are used to reduce resistance, then resistance decreases, but RC delay still increases due to capacitance effects
Solution Approach 1:
The patent changes the dielectric parameter (permittivity) by introducing air gaps with permittivity of approximately 1.0, replacing traditional dielectric materials with permittivity of 3.0 or higher. This parameter change directly reduces the capacitance between interconnect lines, thereby reducing RC delay and improving signal propagation speed while maintaining the low resistance benefit of copper interconnects.
2Length of moving object
If device dimensions are reduced to increase signal speed, then device size decreases, but RC delay increases due to closer interconnect spacing
Solution Approach 1:
The patent applies local quality by introducing air gaps specifically in the regions between interconnect lines where capacitance occurs, while maintaining the compact overall device structure. The air gaps are localized to the dielectric regions between conductors, creating a non-uniform permittivity distribution that reduces capacitance without increasing the overall device footprint.
3Ease of manufacture
If traditional dielectric materials are used to fill interconnect regions, then manufacturing is simplified, but permittivity remains high causing increased capacitance
Solution Approach 1:
The patent extracts the dielectric material from specific regions between interconnect lines, replacing it with air gaps. This removal of dielectric material in targeted areas reduces the permittivity in the interconnect region, thereby reducing capacitance between lines while maintaining the overall structural integrity and manufacturability of the device.
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
The approach significantly reduces line-to-line capacitance and RC delay by lowering the permittivity of the dielectric material, enhancing signal speed and reducing power dissipation in semiconductor devices.
Implementation Method 1
an air gap formed in the second region and extending though the dielectric layer and to the metal barrier layer
Data Source
AI summary
A semiconductor device includes a damascene structure and an air gap embedded in the damascene dielectric layer. A method of manufacturing a semiconductor device includes depositing a metal barrier in advance as an etch stop, forming a copper damascene interconnect structure, forming an air gap, and depositing a photosensitive passivation material on the air gap.