Redistribution Power-Ground Layout for Flexible Lower-Layer Routing
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Solution Overview
Problem
In integrated circuit component manufacturing, the pre-designed power and ground macros limit design flexibility by occupying entire chip areas, preventing the use of these areas for routing other features due to their fixed nature.
Innovation Solution
The design of power-ground (PG) networks in redistribution structures involves placing PG macros only in upper layers, leaving lower layers free for other features, and using a shortest-path scheme to reduce resistance and enhance flexibility by allowing other features to be routed beneath the PG macros.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If pre-designed power and ground macros are used in the layout, then design convenience and efficiency are improved, but design flexibility deteriorates because the entire macro area cannot be used for routing other features
Solution Approach 1:
The patent segments the power-ground network into modular macros that can be independently placed and connected. Each macro is a self-contained unit with defined power and ground connections, allowing designers to select and place individual macros without being constrained by large fixed-area blocks. This segmentation enables flexible routing of other features around and between macros while maintaining design efficiency through standardized modules.
Solution Approach 2:
The patent utilizes multiple metal layers to route power and ground connections in three-dimensional space. By distributing power-ground macros across different layers (e.g., layer 1, layer 2, layer 3) and connecting them through vertical vias, the design achieves flexibility in the horizontal plane while maintaining electrical connectivity through the vertical dimension. This layered approach allows signal routing in areas where macros are present without compromising power delivery.
2Device complexity
If entire macros are tied to VDD or VSS, then power delivery is simplified, but chip area utilization deteriorates because occupied areas cannot be used for other features
Solution Approach 1:
The power-ground network is divided into discrete, independently connectable macros rather than large continuous blocks. Each macro can be selectively connected to VDD or VSS based on local requirements, and other chip features can be routed in the spaces between macros or through areas not occupied by macro footprints. This segmentation increases chip area utilization while maintaining simplified power delivery through standardized macro units.
Solution Approach 2:
The macros are designed as universal building blocks that can serve multiple functions: power delivery, ground reference, and potential signal routing pathways. By making macros multi-functional and independently configurable, the same macro structure can accommodate different design requirements without wasting chip area, as macros can be placed only where needed rather than requiring large reserved regions.
3Reliability
If PG macros extend into lower layers, then power network connectivity is improved, but routing flexibility deteriorates because lower layers are occupied
Solution Approach 1:
The patent confines power-ground macros to upper metal layers (e.g., layer 1, layer 2, layer 3) and uses vertical vias to establish power and ground connections through the substrate. This layered configuration ensures reliable power network connectivity within the macro-containing layers while leaving lower layers completely free for signal routing and other features. The vertical via connections provide the necessary electrical continuity without occupying horizontal space in lower layers.
Solution Approach 2:
The power network is segmented into upper-layer macro structures with vertical connections, separating the power delivery function from the signal routing function in lower layers. This segmentation allows each layer to be optimized for its specific purpose: upper layers for power distribution through macros, lower layers for flexible signal routing, without compromising either function.
Data Source
AI summary
A structure includes a redistribution structure, which includes a bottom layer and a plurality of upper layers over the bottom layer. The redistribution structure also includes a power-ground macro extending from a topmost layer in the plurality of upper layers to a bottommost layer in the plurality of upper layers, and a metal pad in the bottom layer and overlapped by the power-ground macro. The metal pad is electrically disconnected from the power-ground macro.