Semiconductor Cell Layout Using Backside Power Vias to Save Area
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Solution Overview
Problem
The existing design of semiconductor devices faces challenges in reducing the area occupied by power supplies, which limits the space available for other circuit functions.
Innovation Solution
The solution involves distributing voltage domains such as TVDD, VDD, and VSS on the backside of the substrate to an always-on cell, and using backside vias to provide these voltage domains to the front side, while also merging multiple functional cells into a combined cell to optimize area usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If power supplies are provided to perform different functions in standard cells, then the circuit functionality is achieved, but the cell area increases due to power supply occupation
Solution Approach 1:
The patent moves power supply elements from the front side to the back side of the substrate, utilizing the third dimension (depth/layer) to resolve the area conflict. By distributing voltage domains on the backside through backside vias, the front side area is freed for functional circuits while power delivery remains intact.
Solution Approach 2:
The patent segments the power supply distribution by creating separate voltage domains (TVDD, VDD, VSS) that are distributed independently on the backside of the substrate. This segmentation allows selective power delivery to always-on cells versus other functional cells, optimizing area usage.
2Power
If voltage domains are distributed on the front side, then power delivery is achieved, but the separation area between power supply elements and functional elements is wasted
Solution Approach 1:
The patent utilizes the backside of the substrate as another dimension for voltage domain distribution. This eliminates the need for separation areas on the front side between power supply elements and functional elements, as both can coexist on different faces of the same substrate.
3Adaptability or versatility
If multiple functional cells are kept separate, then design flexibility is maintained, but the overall area efficiency decreases
Solution Approach 1:
The patent merges multiple functional cells into combined cells that share common power supply elements on the backside. This merging increases area efficiency while the separate voltage domains maintained on the backside preserve design flexibility for different cell types and functions.
Data Source
AI summary
A method includes: providing a cell of a first group that supplies a first potential from a backside of a substrate, multiple cells of a second group, and two cells of a third group that supply a second potential from the backside; determining a distance in a row direction between the cell of the first group and each of the two cells of the third group; determining a placement of the cell of the first group, the two cells of the third group, and each of the cells of the second group; and counting a number of pins of the cells of the second group. The cell of the first group is located between the two cells of the third group. Each of the cells of the second group is located between the two cells of the third group.