Merged Via-to-Backside Power Rail Structure for Low Contact Resistance
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Solution Overview
Problem
Existing semiconductor devices face challenges in achieving low contact resistance between backside power rails and source/drain regions due to misalignment and overlap issues in the via-to-backside power rail structure.
Innovation Solution
A merged frontside source/drain contact/VBPR structure is introduced, where the frontside source/drain contact is integrated with the VBPR structure, enhancing the overlap and electrical contact with the backside power rail, and is embedded in the MOL dielectric layer with specific spacings and contacts to improve resistivity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a via-to-backside power rail (VBPR) structure is used to connect backside power rail to source/drain region, then power delivery is enabled, but contact resistance is high due to misalignment and overlap issues
Solution Approach 1:
The patent merges the frontside source/drain contact structure with the VBPR structure into a single integrated structure. This merging eliminates the need for separate alignment steps between the contact and VBPR, thereby reducing contact resistance caused by misalignment while maintaining manufacturing feasibility through a unified structure formation process
2Ease of manufacture
If standard cells are used as base unit for designing integrated circuits, then design and manufacture costs are reduced, but power delivery efficiency is insufficient
Solution Approach 1:
The patent introduces backside power rails formed on the backside of the semiconductor substrate, utilizing the third dimension (vertical dimension through substrate thickness) to deliver power. This dimensional approach enables efficient power delivery to standard cells without affecting their planar design and manufacturing advantages, as the power rails are formed in a different spatial plane
Data Source
AI summary
A semiconductor device including a frontside source/drain contact/via-to-backside power rail (VBPR) structure is provided in which the overlap between the frontside source/drain contact structure of the merged frontside source/drain contact/VBPR structure and the VBPR structure of the merged frontside source/drain contact/VBPR structure is improved. The improved overlap, in turn, provides a structure having low contact resistance.