Via-to-Wiring Barrier Layer for Stable Semiconductor Interconnects
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Solution Overview
Problem
In semiconductor device manufacturing, the materials used for wiring and via plugs often react with each other, leading to issues such as diffusion of components and changes in electrical resistance, which can compromise the reliability of the wiring.
Innovation Solution
A semiconductor device structure is developed where a metal oxide or metal nitride layer is inserted between the upper end of the via plug and the lower end of the wiring to prevent reactions, using a metal layer containing titanium that is diffused and oxidized to form a titanium oxide or nitride layer, thereby reducing reactivity with chlorine and fluorine residues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a via plug is formed on a wiring, then electrical connection is achieved, but material reaction between wiring and via plug occurs causing diffusion and resistance changes
Solution Approach 1:
A barrier metal layer is introduced as an intermediary between the wiring and via plug. This barrier layer prevents direct contact and chemical reaction between the wiring material (e.g., Cu, Al) and via plug material (e.g., W, Co), thereby eliminating diffusion and resistance changes while maintaining electrical connection integrity
Solution Approach 2:
The wiring structure is designed as a composite multi-layer system consisting of wiring material layer and barrier metal layer. This composite structure combines the electrical conductivity of the wiring material with the chemical stability of the barrier metal, preventing harmful reactions while preserving electrical function
2Reliability
If barrier metal layer is added to prevent reaction, then wiring reliability improves, but device complexity increases
Solution Approach 1:
The barrier metal layer formation is merged with existing manufacturing processes such as sputtering or atomic layer deposition (ALD) that are already used for other thin film formations. This integration approach adds the protective barrier function without requiring entirely new process equipment or steps, thereby limiting the increase in device complexity
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 solution effectively prevents reactions between the wiring and via plugs, ensuring stable electrical resistance and improved reliability by forming a low-reactivity metal oxide or nitride layer that secures the integrity of the semiconductor device.
Implementation Method 1
a metal layer containing titanium that is diffused and oxidized to form a titanium oxide or nitride layer
Implementation Method 2
a metal layer containing titanium that is diffused and oxidized to form a titanium oxide or nitride layer
Data Source
AI summary
A semiconductor device includes a first substrate, a logical circuit, a first insulating film, a wiring, a plug, and a first layer containing a metal oxide or a metal nitride. The logical circuit is disposed on the first substrate. The first insulating film is disposed above the logical circuit. The wiring includes a first film disposed in the first insulating film, the first film extending in a first direction along an upper surface of the first substrate, and the first film containing a metal, and a first metal layer disposed in the first insulating film via the first film. The plug is disposed under the wiring, extends in a second direction that intersects the first direction, and is electrically connected to the wiring. The first layer is provided between an upper end of the plug and a bottom end of the wiring.