Backside Diagonal Metal Routing for Shorter IC Signal Paths
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Solution Overview
Problem
Conventional integrated circuit layouts using Manhattan routing for metal conductors are not always the most efficient in routing signals and power, as they do not always take the shortest path between components, leading to potential delays and signal losses.
Innovation Solution
The implementation of diagonal routing for backside metal layers in integrated circuits, in addition to Manhattan routing for frontside layers, allows for more efficient signal and power delivery by using diagonal metal conductors that can connect components at angles other than orthogonal to the design boundary, reducing conductor lengths and optimizing timing for time-critical nets.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If Manhattan routing is used for metal conductors, then the layout is simple and easy to manufacture, but the conductor length is longer and signal transmission is less efficient
Solution Approach 1:
The patent introduces diagonal routing as a new dimension of conductor layout beyond traditional orthogonal Manhattan routing. By allowing conductors to extend in diagonal directions (e.g., 45 degrees) in addition to horizontal and vertical directions, the routing space is expanded, enabling shorter paths between components while maintaining manufacturing feasibility through standardized diagonal track pitches.
2Productivity
If diagonal routing is used for metal conductors, then the conductor length is shorter and signal transmission is more efficient, but the layout complexity increases
Solution Approach 1:
The patent applies diagonal routing selectively to specific regions or layers (e.g., backside metal layers) rather than uniformly across the entire circuit. This localized application reduces overall layout complexity while still capturing the performance benefits of shorter diagonal paths where they are most beneficial, such as for time-critical signal nets.
Solution Approach 2:
The routing system is segmented into different routing domains: Manhattan routing for frontside layers and diagonal routing for backside layers. This segmentation allows each layer type to be optimized independently with appropriate routing rules, simplifying the overall design process while achieving superior performance through the combination of both routing styles.
3Ease of manufacture
If conventional metal conductor layouts are used, then the manufacturing process is straightforward, but power and signal routing efficiency is insufficient
Solution Approach 1:
The patent extends the conventional two-dimensional orthogonal routing grid by incorporating diagonal dimensions. This creates a multi-directional routing fabric that provides more direct paths for power and signal distribution, reducing the number of bends and vias required while maintaining compatibility with existing manufacturing processes through standardized diagonal track spacing.
Data Source
AI summary
An integrated circuit includes a device, a first interconnect structure disposed above the device and a second interconnect structure positioned below the device. The first interconnect structure includes multiple frontside metal layers. The second interconnect structure includes multiple backside metal layers, where each backside metal layer includes metal conductors routed according to diagonal routing. In some embodiments, a backside interconnect structure can include another backside metal layer that includes metal conductors routed according to mixed-Manhattan-diagonal routing. A variety of techniques can be used to route signals between metal conductors in the backside interconnect structure and cells on one or more frontside metal layers.