Stepped Trench Via Structure for Low-Resistance Wiring Contact
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Solution Overview
Problem
The increasing resistance between wiring and via in semiconductor devices due to down-scaling poses a challenge, affecting the reliability of semiconductor chips.
Innovation Solution
A semiconductor device design where the plug conductive film is brought into direct contact with the wiring, reducing resistance by increasing the contact area and eliminating the need for a barrier conductive film between them.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If down-scaling of semiconductor elements is implemented, then integration density increases, but resistance between wiring and via increases
Solution Approach 1:
The patent transitions from a conventional via structure to a trench structure with stepped configuration. The trench extends deeper into the substrate and includes multiple levels (first trench, second trench, third trench) at different depths, creating a three-dimensional contact structure that increases the contact area between the conductive plug and wiring while maintaining small surface footprint.
Solution Approach 2:
The patent implements a nested trench structure where the first trench, second trench, and third trench are positioned at different depths and horizontally offset from each other. The conductive plug is sequentially formed in each trench, creating a nested configuration where deeper trenches are positioned within the horizontal projection of upper trenches, maximizing contact area within limited space.
2Reliability
If direct contact between plug conductive film and wiring is achieved, then interfacial resistance decreases, but manufacturing complexity increases
Solution Approach 1:
The patent divides the via formation process into multiple discrete steps, each forming a conductive plug in a separate trench. The first conductive plug is formed in the first trench, the second conductive plug in the second trench, and the third conductive plug in the third trench. This segmentation allows each plug to be independently formed and optimized, ensuring direct contact with the wiring while managing manufacturing complexity through systematic process breakdown.
Data Source
AI summary
A semiconductor device may include a first film and a second film defining parts of a trench, a plug conductive film, a via, and a wiring in the trench. The trench may include a second sub-trench having a second width below a first sub-trench having a first width. The plug conductive film may extend from a first side of the first film to penetrate a bottom face of the trench. An uppermost face of the plug conducive film may be in the trench. The via may include an insulating liner between the plug conductive film and the first film. The uppermost face of the plug conductive film and at least a part of a side wall of the plug conductive film may be in contact with the wiring. An upper face of the insulating liner may be exposed by a bottom face of the second sub-trench.