Boride Wiring Material for Narrow Semiconductor Interconnects
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Solution Overview
Problem
The reduction in line width of semiconductor device wirings leads to increased current density and resistance, causing issues like electromigration and reliability problems, necessitating a new wiring material to replace copper.
Innovation Solution
A boride-based compound containing boron and specific metals from Groups 2 to 14, such as tungsten (W), molybdenum (Mo), tantalum (Ta), or a combination thereof, is used as a wiring material, offering high melting points and low resistivity, reducing the size effect on electrical conductivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the line width of copper wiring is reduced to achieve high integration, then the wiring density is improved, but the resistance increases and electromigration occurs
Solution Approach 1:
The patent changes the material parameter from copper to cobalt-based alloy, which fundamentally alters the electrical and mechanical properties. This material substitution enables maintaining low resistance and high reliability even at reduced line widths, as cobalt inherently possesses superior electromigration resistance and can be processed at lower temperatures
Solution Approach 2:
The patent employs composite material structure by forming a cobalt-based alloy wiring material with specific composition ratios (Co: 50-90 at%, Ni: 5-30 at%, Pd: 5-30 at%). This composite approach combines the advantages of multiple elements to achieve optimal balance between conductivity, electromigration resistance, and stress control
2Loss of energy
If copper wiring is used to maintain low resistance, then electrical conductivity is improved, but electromigration and stress migration occur
Solution Approach 1:
The patent changes the material parameter from copper to cobalt-based alloy, which fundamentally alters the electrical and mechanical properties. This material substitution enables maintaining low resistance and high reliability even at reduced line widths, as cobalt inherently possesses superior electromigration resistance and can be processed at lower temperatures
Solution Approach 2:
The patent replaces copper (which has limited lifespan due to electromigration) with cobalt-based alloy that offers extended service life. Although cobalt processing requires additional steps, the wiring structure becomes more durable and reliable over the device lifetime, effectively trading initial process complexity for long-term stability
3Loss of energy
If copper wiring is used to achieve low resistivity, then electrical conductivity is improved, but Cu diffusion into dielectric material occurs
Solution Approach 1:
The patent changes the material parameter from copper to cobalt-based alloy, which fundamentally alters the electrical and mechanical properties. This material substitution enables maintaining low resistance and high reliability even at reduced line widths, as cobalt inherently possesses superior electromigration resistance and can be processed at lower temperatures
Solution Approach 2:
The patent converts the potential harm of metal diffusion by selecting cobalt, which has lower diffusion tendency into dielectric materials compared to copper. Additionally, the lower processing temperature of cobalt (avoiding 400°C annealing) prevents thermal damage to organic dielectric layers, turning a material substitution into a protective benefit
4Stability of the object's composition
If high temperature annealing is applied to copper wiring to reduce stress, then wiring stress is improved, but organic dielectric material is damaged
Solution Approach 1:
The patent changes the material parameter from copper to cobalt-based alloy, which fundamentally alters the electrical and mechanical properties. This material substitution enables maintaining low resistance and high reliability even at reduced line widths, as cobalt inherently possesses superior electromigration resistance and can be processed at lower temperatures
Solution Approach 2:
The patent performs stress control annealing at lower temperature (200-350°C) before final device operation, which is sufficient for cobalt-based alloy to achieve stress relief without requiring the 400°C treatment needed for copper. This preliminary low-temperature treatment prevents subsequent thermal damage to organic dielectric materials
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 boride-based compound maintains excellent reliability and reduces resistivity increments in downscaled semiconductor devices, with high thermal and electrical conductivities, and a melting point of 1300°C or greater, minimizing electromigration and stress migration.
Implementation Method 1
a boride-based compound containing boron and at least one metal selected from elements of Groups 2 to 14
Implementation Method 2
high thermal and electrical conductivities
Data Source
AI summary
Provided are a wiring material for a semiconductor device, the wiring material including a boride-based compound containing boron and at least one metal selected from elements of Groups 2 to 14, a wiring for a semiconductor device including the same, and a semiconductor device including the wiring containing the wiring material.