Pass-Through Structures for Backside-to-Topside Signal Routing
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Solution Overview
Problem
Existing chip layouts face challenges in signal routing due to obstructions in metal layers, particularly between backside and topside metal layers, leading to congestion and reduced flexibility in routing signals.
Innovation Solution
The implementation of pass-through filler cells with pass-through structures that allow signal routing between backside and topside metal layers, utilizing backside metal routing to bypass obstructions and optimize signal paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional metal layer routing is used, then signal routing is straightforward within each layer, but routing congestion occurs and flexibility is reduced when routing between backside and topside metal layers
Solution Approach 1:
The patent introduces pass-through structures that extend vertically through the substrate, enabling signals to route from backside metal layers to topside metal layers through a third dimension. This vertical routing path bypasses the congestion in traditional planar metal layers, allowing signals to leap over obstructions and reducing routing complexity in the horizontal plane.
Solution Approach 2:
The pass-through structures act as intermediary elements that connect backside and topside metal layers. These structures include diffusion regions, contacts, and conductive pathways that mediate the signal transfer between layers, enabling flexible routing without direct exposure or complex via structures.
2Productivity
If backside contacts are used to access bottom surfaces, then additional routing paths are available, but parasitic capacitances and IR drops increase
Solution Approach 1:
By routing signals vertically through pass-through structures rather than horizontally across long distances in metal layers, the patent reduces the length of conductive paths. This dimensional change minimizes the exposure of conductive materials to electric fields, thereby reducing parasitic capacitance and resistive losses.
Solution Approach 2:
The pass-through structures provide continuous conductive pathways from backside to topside, eliminating discontinuities and multiple connection points that would otherwise be required. This continuity reduces the number of interfaces where parasitic effects can occur, maintaining signal integrity throughout the routing path.
Data Source
AI summary
A chip includes a first transistor including a first source/drain, a second source/drain, a gate between the first source/drain and the second source/drain, and a first backside contact coupled to a bottom surface of the first source/drain. The chip also includes a pass-through structure including a first diffusion region extending in a first direction, a second backside contact coupled to a bottom surface of the first diffusion region, and a topside contact coupled to a top surface of the first diffusion region. The chip also includes a backside metal routing coupled between the first backside contact and the second backside contact.