BEOL Wiring Barrier Structure for Stable Scaled Interconnects
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Solution Overview
Problem
The challenge of stably connecting wires in semiconductor devices with reduced feature sizes has hindered the improvement of device performance and reliability, particularly in the BEOL process.
Innovation Solution
The semiconductor device incorporates a unique wiring structure design with specific barrier films and filling materials, including a first lower barrier film with a concave upper surface and an upper wiring structure connected to the lower wiring structure, enhancing the stability and reliability of wire connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If feature size is decreased to increase integration density, then integration density is improved, but wire connection stability deteriorates
Solution Approach 1:
The barrier film is divided into multiple segments along the wire depth direction, with each segment having different thicknesses. This segmentation allows optimization of electrical isolation at different depths while maintaining overall connection stability, resolving the contradiction between miniaturization and connection reliability.
Solution Approach 2:
Different regions of the barrier film have different thicknesses tailored to local requirements. The first barrier film portion has greater thickness where electrical isolation is most critical, while other regions have reduced thickness to minimize space occupation, enabling stable wire connections in scaled-down devices.
2Reliability
If barrier film thickness is increased to prevent short circuits, then electrical isolation is improved, but space for wire filling deteriorates
Solution Approach 1:
The barrier film is segmented into multiple portions with different thicknesses along the wire depth direction. This allows the film to provide adequate electrical isolation where needed while occupying minimal space in the overall wire structure, resolving the space constraint issue.
Solution Approach 2:
Instead of uniformly increasing barrier film thickness throughout, the invention applies excessive thickness only in specific critical regions (first barrier film portion) where electrical isolation is most needed, while using reduced thickness in other regions, optimizing the balance between isolation and space utilization.
Data Source
AI summary
A semiconductor device is provided. The semiconductor device includes: a first interlayer insulating film defining a lower wiring trench; a lower wiring structure including a first lower barrier film which extends along sidewalls of the lower wiring trench, and a lower filling film which is on the first lower barrier film; a second interlayer insulating film on the first interlayer insulating film, the second interlayer insulating film defining an upper wiring trench which exposes at least part of the lower wiring structure; and an upper wiring structure provided in the upper wiring trench and connected to the lower wiring structure. An upper surface of the first lower barrier film is closer to a bottom surface of the lower wiring trench than each of an upper surface of the first interlayer insulating film and an upper surface the lower filling film. The upper surface of the first lower barrier film is concave.