Backside Source/Drain Contact Structure for Dense PDN IR Drop
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Solution Overview
Problem
As semiconductor devices become increasingly highly integrated, voltage drop (IR drop) in the power distribution network (PDN) supplying power to integrated circuits becomes a significant issue, affecting the reliability, speed, and functionality of these devices.
Innovation Solution
The semiconductor device incorporates a back side power delivery network (BSPDN) with a back side source/drain contact that extends along the side face of the source/drain pattern, connected to a back side wiring structure through a first pillar and a wrapping part that protrudes beyond the upper face of the pillar, and is in contact with an etch stop layer, enhancing power distribution efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the width of wiring patterns and via patterns is decreased to achieve higher integration, then the integration level increases, but voltage drop (IR drop) in the power distribution network increases
Solution Approach 1:
The patent introduces a back side source/drain contact that extends from the lower side of the substrate up to contact the etch stop layer, utilizing the vertical dimension (third direction) to create an additional power delivery path. This three-dimensional contact structure allows power to be delivered from the back side, effectively adding another dimension to the traditional planar power distribution network, thereby reducing voltage drop without requiring wider front-side wiring patterns.
2Productivity
If the back side source/drain contact extends along the side face of the source/drain pattern, then power distribution efficiency improves, but device complexity increases
Solution Approach 1:
The back side source/drain contact is segmented into two functional parts: a first pillar portion extending vertically from the lower side of the substrate, and a first wrapping part that protrudes and extends along the side face of the source/drain pattern. This segmentation allows each part to perform its specific function optimally while simplifying the overall fabrication process through standardized formation steps.
Solution Approach 2:
The first wrapping part of the back side source/drain contact is positioned to extend along and wrap around the side face of the source/drain pattern, creating a nested configuration where the contact structure integrates with the existing device geometry without requiring additional external components or complex assembly steps.
Data Source
AI summary
Provided is a semiconductor device including: a substrate; an active pattern on an upper side of the substrate; a gate structure on and intersecting the active pattern; a source/drain pattern on a side face of the gate structure and connected to the active pattern; an etch stop layer extending along an upper side of the substrate and an outer face of the source/drain pattern; a back side source/drain contact in the substrate, the back side source/drain contact being connected to the source/drain pattern; and a back side wiring structure on a lower side of the substrate and connected to the back side source/drain contact, wherein the back side source/drain contact extends along a part of a side face of the source/drain pattern, and wherein a part of the back side source/drain contact farthest from the lower side of the substrate is in contact with the etch stop layer.