Boron Nitride Interconnect Passivation for Low-Resistance Wiring
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Solution Overview
Problem
As semiconductor devices strive for higher density and performance, the reduction in metal wiring line width and thickness leads to increased resistance due to grain-boundary scattering and surface-roughness scattering, while also making them susceptible to oxidation, necessitating a solution to reduce resistance and prevent oxidation.
Innovation Solution
An interconnect structure is developed with a substrate, a conductive layer, and a passivation layer comprising hexagonal boron nitride (h-BN) and amorphous boron nitride (a-BN), where the h-BN forms van der Waals bonds with the conductive layer to reduce scattering effects and prevent oxidation, and is formed through a low-temperature process by converting a-BN at the interface between the dielectric layer and the conductive layer.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the line width or thickness of metal wiring is reduced to increase integration density, then the number of semiconductor chips integrated per wafer increases, but the resistance increases rapidly due to grain-boundary scattering and surface-roughness scattering
Solution Approach 1:
A boron nitride layer is introduced as an intermediary substance between the metal wiring and its environment. This layer has extremely low carbon concentration, preventing carbon contamination of the metal wiring while maintaining low wiring resistance and enabling high integration density
Solution Approach 2:
The carbon concentration in the boron nitride layer is controlled to be extremely low (≤1×10^19 atoms/cm³), which is a critical parameter change. This low carbon concentration prevents carbon contamination of the metal wiring, thereby maintaining low wiring resistance while allowing reduced line width for higher integration
2Speed
If the line width or thickness of metal wiring is reduced to increase integration density, then the capacitance of the line is reduced and signal speed increases, but the resistance increases rapidly
Solution Approach 1:
The boron nitride layer serves as a mediator that prevents carbon contamination of the metal wiring. By controlling carbon concentration to be extremely low, the layer maintains low wiring resistance even when line width is reduced for faster signal transmission
Solution Approach 2:
The boron nitride layer creates an inert environment around the metal wiring by having extremely low carbon concentration. This prevents carbon contamination and maintains low resistance, enabling reduced line width for faster signal transmission
3Speed
If the thickness of metal wiring is thinned to reduce capacitance and increase signal speed, then the capacitance decreases and signal speed increases, but the resistance increases rapidly due to grain-boundary scattering and surface-roughness scattering
Solution Approach 1:
The boron nitride layer with extremely low carbon concentration acts as a mediator that prevents carbon contamination of the thinned metal wiring. This maintains low wiring resistance even when the wiring is thinned for reduced capacitance and faster signal transmission
4Productivity
If conventional wiring technology is used to reduce line width, then integration density increases, but resistivity increases significantly due to grain-boundary scattering and surface-roughness scattering
Solution Approach 1:
The boron nitride layer is introduced as an intermediary with extremely low carbon concentration, preventing carbon contamination of the metal wiring. This enables reduced line width for higher integration density while maintaining low wiring resistivity
Solution Approach 2:
The carbon concentration in the boron nitride layer is controlled to be extremely low (≤1×10^19 atoms/cm³), which prevents carbon contamination and maintains low wiring resistivity even when line width is reduced for higher integration
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 structure effectively reduces the increase in resistance and prevents oxidation, thereby improving signal transmission and device performance without the negative effects of high-temperature deposition processes.
Implementation Method 1
the h-BN forms van der Waals bonds with the conductive layer to reduce scattering effects and prevent oxidation
Data Source
AI summary
Disclosed is an interconnect structure including a substrate, a conductive layer on the substrate, and a passivation layer in contact with the conductive layer, where the passivation layer includes a first layer including boron nitride (h-BN) having a hexagonal crystal structure and a second layer including amorphous boron nitride (a-BN), and the first layer is in contact with the conductive layer the first layer.