Lateral Diode Structure for Backside Power Rail Thinning
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Solution Overview
Problem
Conventional diodes in backside power delivery designs for semiconductor wafers face issues with current path disruption due to thinning, as N-well/P-well connections are cut off during polishing, affecting current transport.
Innovation Solution
A semiconductor structure with metal gate structures and S/D contacts on N-well or P-well, including a dummy gate structure as an oxide definition edge pattern, forms a continuous current path using epitaxial layers to maintain current flow even during substrate thinning.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the wafer is thinned by polish for backside power delivery, then the power delivery efficiency is improved, but the N-well/P-well connections are cut off causing current path disruption
Solution Approach 1:
The patent transitions from vertical current paths (through substrate thickness) to lateral current paths (along the substrate surface). By forming source/drain regions and gate structures in a planar configuration, the current flows laterally through epitaxial layers rather than vertically through the substrate thickness, thus maintaining current path continuity even when the substrate is thinned for backside power delivery.
2Ease of manufacture
If conventional diode structure with P+ and N+ epitaxy on different oxide definitions is used, then the diode function is achieved, but the current path disappears when substrate is thinned
Solution Approach 1:
The patent merges the source and drain regions into the same epitaxial layer (both N-type or both P-type), eliminating the need for separate oxide definitions for P+ and N+ epitaxy. This unified structure allows current to flow continuously through the epitaxial layer laterally, maintaining diode functionality even when the substrate is thinned for backside power delivery.
3Productivity
If backside power delivery is implemented, then the need to share interconnect resources is eliminated, but the conventional diode current path is disrupted
Solution Approach 1:
The patent creates a dynamic current path that adapts to the thinned substrate condition. By forming lateral current paths through epitaxial layers with source/drain regions extending laterally, the structure dynamically maintains current flow continuity even as the substrate thickness changes during thinning processes, enabling both backside power delivery and proper diode operation.
Data Source
AI summary
The present invention provides a semiconductor structure, wherein the semiconductor structure includes an oxide definition region, a plurality of metal gate structures and a plurality of S/D contacts. The oxide definition region is disposed over a semiconductor substrate and surrounded by insulating regions. The plurality of metal gate structures are disposed on an N-well or a P-well manufactured on the semiconductor substrate. The plurality of S/D contacts are disposed on the N-well or the P-well manufactured on the semiconductor substrate. In addition, the plurality of metal gate structures, the plurality of S/D contacts and the at least one dummy gate structure are within the oxide definition region.