Dummy Metal Wiring for Hydrogen Diffusion in Semiconductor Devices
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Solution Overview
Problem
Highly scaled semiconductor devices face damage and performance issues due to refined patterns and stacked wiring structures, which affect operating speed and refresh characteristics, particularly due to increased distances between wirings and contact plugs.
Innovation Solution
The implementation of dummy wirings and contact plugs at different vertical levels, electrically floated and connected in specific configurations, forms continuous material paths to allow hydrogen diffusion, thereby reducing substrate damage and improving performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If distances between wirings and contact plugs are reduced to achieve high integration, then device density improves, but substrate damage increases and operating speed deteriorates
Solution Approach 1:
The patent introduces a vertical dimension by forming dummy contact plugs at multiple depth levels (first depth, second depth, third depth) beneath the substrate surface. This three-dimensional arrangement allows hydrogen to diffuse from multiple vertical positions simultaneously, effectively treating the substrate damage problem by adding spatial dimensionality to the hydrogen supply path rather than increasing horizontal wiring density.
Solution Approach 2:
The dummy contact plugs serve as intermediary structures that facilitate hydrogen diffusion to the substrate. These non-conductive plugs act as mediators between the hydrogen source and the substrate, providing dedicated diffusion pathways that do not interfere with the functional wiring architecture, thus resolving the conflict between high density and substrate protection.
2Quantity of substance
If distances between wirings and contact plugs are reduced, then device density improves, but operating speed and refresh characteristics worsen
Solution Approach 1:
By distributing dummy contact plugs across multiple vertical depths, the patent creates parallel hydrogen diffusion pathways that operate simultaneously. This multi-level vertical arrangement improves refresh characteristics and operating speed by providing redundant hydrogen supply routes, while maintaining the reduced horizontal distances needed for high device density.
3Object-affected harmful factors
If additional processing steps are added to improve substrate quality, then substrate damage decreases, but processing time increases
Solution Approach 1:
The patent merges the dummy contact plug formation with the existing contact plug fabrication process. The same photolithography and etching steps used for creating functional contact plugs are simultaneously used to create the dummy contact plugs at various depths. This integration eliminates the need for separate processing sequences, reducing overall processing time while still providing the substrate protection benefits.
Solution Approach 2:
The dummy contact plugs serve multiple functions: they provide hydrogen diffusion pathways to prevent substrate damage, they act as spacers to maintain proper wiring spacing, and they can be formed using the same manufacturing processes as functional contact plugs. This multi-functionality reduces the need for additional specialized processing steps.
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 reduces substrate damage and enhances operating speed and refresh characteristics by ensuring sufficient hydrogen diffusion to cure dangling bond defects, without requiring additional processing steps or increasing processing time.
Implementation Method 1
At least two elements among the plurality of dummy wirings and the plurality of dummy contact plugs may form a continuous material movement path to allow hydrogen to diffuse through the continuous material movement path
Data Source
AI summary
A semiconductor device may include a plurality of dummy wirings formed on a substrate at different vertical levels and electrically floated and a plurality of dummy contact plugs each electrically connected between two adjacent dummy wirings of the plurality of dummy wiring of the plurality of dummy wirings. No dummy wiring of the plurality of dummy wirings is electrically connected to a terminal of any one of a plurality of transistors included in the substrate.