Vertical Source/Drain Contact for Backside Power Rail Routing
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Solution Overview
Problem
As semiconductor devices scale down, nanosheets interfere with each other, and forming connections to a backside power network becomes increasingly difficult due to limited space.
Innovation Solution
A semiconductor device structure is developed with a first source/drain contact that extends vertically past the first source/drain, allowing a backside power rail to be connected through the active region, reducing the risk of shorting and improving connectivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If devices are scaled down and placed closer together, then device density is improved, but the risk of shorting between devices increases
Solution Approach 1:
The source/drain contact extends vertically through multiple layers (into the active region) rather than remaining in a single planar layer. This three-dimensional contact structure allows electrical connection while maintaining horizontal spacing between adjacent devices, thus reducing shorting risk while preserving high device density.
2Productivity
If devices are scaled down and placed closer together, then device density is improved, but forming connections to backside power network becomes more difficult
Solution Approach 1:
The contact structure extends vertically into the active region, providing an additional dimensional pathway for forming connections to the backside power network. This vertical extension creates more accessible contact points and simplifies the formation of reliable electrical connections despite reduced device spacing.
Solution Approach 2:
The extended source/drain contact acts as an intermediary structure that bridges the gap between the densely packed device regions and the backside power network. This intermediate vertical contact facilitates easier connection formation by providing a dedicated pathway through the intermediate layers.
3Ease of manufacture
If source/drain contact is formed directly atop source/drain, then manufacturing simplicity is improved, but connection reliability to backside power network deteriorates
Solution Approach 1:
The source/drain contact extends vertically into the active region, transforming from a simple planar contact to a three-dimensional structure. This vertical extension maintains manufacturing simplicity through standard deposition processes while simultaneously improving connection reliability by creating direct electrical pathways to the backside power network.
Data Source
AI summary
According to the embodiment of the present invention, a semiconductor device includes a first source/drain and a second source/drain. A first source/drain contact includes a first portion and a second portion. The first portion of the first source/drain contact is located directly atop the first source/drain. The second portion of the first source/drain contact extends vertically past the first source/drain. The first source/drain is in direct contact with three different sides of a first section of the second portion of the first source/drain contact.