Multilayer Via Fill Structure for Stable Semiconductor Interconnects
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Solution Overview
Problem
The challenge of achieving stable connections between lines in semiconductor devices as feature sizes decrease, impacting element performance and reliability, is not adequately addressed by existing technologies.
Innovation Solution
A semiconductor device design that includes a lower line structure with an upper interlayer insulating film having upper line trenches, and an upper line structure comprising an upper barrier film and filling films, which are strategically formed to enhance connectivity and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If feature size is decreased to increase integration and reduce power consumption, then element performance and reliability are improved, but connection stability between lines deteriorates
Solution Approach 1:
The upper line structure is segmented into multiple functional layers: upper barrier film, upper liner, and upper filling film. This segmentation allows each layer to perform its specific function - the barrier film prevents diffusion, the liner provides adhesion, and the filling film ensures stable electrical connection, thereby resolving the contradiction between reduced feature size and connection stability
Solution Approach 2:
The patent employs composite material structure with multiple films having different properties. The upper barrier film (e.g., tantalum nitride or ruthenium), upper liner (e.g., tungsten or molybdenum), and upper filling film (e.g., copper or aluminum) form a composite structure that combines diffusion resistance, adhesion, and electrical conductivity properties, enabling stable connections at reduced feature sizes
2Reliability
If complex multi-layer film structures are used to improve connection stability, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent applies local quality by providing different film structures at different locations. The upper barrier film is selectively formed at the interface between the upper line structure and upper interlayer insulating film where diffusion protection is most critical, while the upper liner and filling film are provided where adhesion and electrical connection are needed, optimizing reliability without unnecessary complexity throughout the entire structure
Data Source
AI summary
A semiconductor device is provided. The semiconductor device includes: a lower line structure; an upper interlayer insulating film provided on the lower line structure and having a trench formed therein, wherein the trench includes a wiring line trench and a via trench extending from the wiring line trench to the lower line structure; and an upper line structure provided in the line trench, wherein the upper line structure includes an upper barrier film and an upper filling film. The upper filling film includes a first sub-filling film in contact with the upper interlayer insulating film, and a second sub-filling film provided on the first sub-filling film. The first sub-filling film fills an entirety of the upper via trench and covers at least a portion of a bottom surface of the upper wiring line trench.