Boride Interconnect Material for Low-Resistance Narrow Wiring
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Solution Overview
Problem
As semiconductor devices shrink, the increased current density in copper wiring leads to higher resistance, electromigration, and reliability issues such as wiring stress migration and Cu diffusion, necessitating a new wiring material that maintains conductivity and reliability.
Innovation Solution
A boride-based compound containing boron and specific metals from Groups 2 to 14, with a high melting point and low mean free path, is used as a wiring material to reduce resistivity increments and enhance reliability, offering excellent thermal and electrical conductivities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If copper wiring is used to maintain electrical conductivity, then electrical conductivity is improved, but resistance increases and reliability deteriorates as device size decreases
Solution Approach 1:
The patent changes the material parameter from copper to tungsten, which has fundamentally different electrical and mechanical properties. Tungsten maintains low resistance even at reduced line widths and offers superior electromigration resistance, directly resolving the reliability issue while accommodating continued line width scaling
Solution Approach 2:
The patent employs a composite structure with tungsten wiring and copper plug. The tungsten wiring provides mechanical strength and electromigration resistance, while copper plugs provide excellent electrical conductivity for vertical connections. This composite approach optimizes both reliability and electrical performance
2Productivity
If line width of wiring is reduced to achieve high integration, then integration density is improved, but current density increases leading to higher resistance
Solution Approach 1:
The patent changes the material parameter from copper to tungsten, which has a shorter mean free path and maintains lower resistance at reduced dimensions. This allows continued scaling of line width for higher integration while preventing the resistance increase that would otherwise occur
3Reliability
If copper wiring is used to maintain conductivity, then electrical conductivity is improved, but electromigration and stress migration occur reducing durability
Solution Approach 1:
The patent acknowledges that copper's high conductivity is accompanied by high electromigration susceptibility. By switching to tungsten, the patent converts the potential harm of electromigration into a benefit: tungsten's superior electromigration resistance becomes the key reliability advantage, even though its bulk conductivity is lower
Solution Approach 2:
The patent changes the material parameter from copper to tungsten, which has fundamentally different mechanical and electrical properties. Tungsten maintains structural integrity under stress and resists electromigration, directly eliminating the harmful effects while maintaining acceptable conductivity
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 provides reduced resistivity increments and improved reliability even at reduced device sizes, with high melting points and excellent thermal and electrical conductivities, outperforming traditional copper wiring in semiconductor devices.
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
with high melting points and excellent 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.