Tungsten Via Plug on Copper Wiring Without Titanium Nitride
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Solution Overview
Problem
The existing semiconductor manufacturing processes often result in reactions between copper wiring and tungsten via plugs, particularly when a titanium nitride barrier layer is used, leading to potential short circuits and reliability issues.
Innovation Solution
The use of an aluminum oxide or silicon oxide insulating film between the copper wiring and the tungsten via plug, eliminating the need for a titanium nitride layer and preventing reactions, while ensuring electrical connectivity by forming the tungsten plug directly on the copper wiring.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a titanium nitride barrier layer is used between copper wiring and tungsten via plug, then reaction prevention is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent removes the titanium nitride barrier layer from the conventional structure, extracting the problematic intermediate layer that caused manufacturing complexity while maintaining reaction prevention through direct contact between copper wiring and tungsten via plug
Solution Approach 2:
The patent creates an asymmetric interface by eliminating the symmetric barrier layer structure, allowing direct contact between copper wiring and tungsten via plug, which simplifies the overall structure while maintaining functional integrity through controlled material properties
2Reliability
If a titanium nitride barrier layer is used between copper wiring and tungsten via plug, then reaction prevention is improved, but manufacturing cost and process complexity increase
Solution Approach 1:
The patent extracts the titanium nitride barrier layer from the manufacturing process, eliminating the additional deposition and etching steps required for this intermediate layer, thereby simplifying the manufacturing process while achieving reaction prevention through direct material interface
Solution Approach 2:
The patent merges the functions of the barrier layer into the inherent properties of the copper wiring and tungsten via plug interface, eliminating the need for a separate titanium nitride layer and its associated manufacturing steps
Data Source
AI summary
A semiconductor device includes a substrate, a logic circuit provided on the substrate, a wiring layer including a plurality of wirings that are provided above the logic circuit, a first insulating film below the wiring layer, a plug, and a second insulating film. Each of the wirings contains copper and extends along a surface plane of the substrate in a first direction. The wirings are arranged along the surface plane of the substrate in a second direction different from the first direction. The plug extends through the first insulating film in a third direction crossing the first and second directions and is electrically connected to one of the wirings. The plug contains tungsten. The second insulating film is provided between the first insulating film and the plug.