Semiconductor Cell Layout With Taller Cells for Wider Diffusion
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Solution Overview
Problem
As semiconductor device heights become shorter, diffusion structures become smaller, leading to reduced performance and limiting further reductions in semiconductor process feature size, particularly in Gate-All-Around (GAA) FET-based designs.
Innovation Solution
Introduce double-height and 1.5-height cells with increased diffusion structure widths, utilizing GAA FET, finFET, or CFET technologies, and employ filler cells to transition between different height cells, enabling larger active diffusion structures that extend across power rails.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If device height is reduced to achieve smaller diffusion structures, then area is reduced, but performance deteriorates
Solution Approach 1:
The patent transitions from two-dimensional planar diffusion structures to three-dimensional vertically-stacked diffusion structures. Multiple diffusion structures are arranged in the vertical dimension (stacked along the channel direction), allowing the device to achieve larger effective diffusion area without increasing the lateral footprint. This vertical stacking enables continued scaling by utilizing the third dimension (height) to compensate for the reduction in lateral dimensions.
Solution Approach 2:
The patent implements nested diffusion structures where multiple diffusion regions are stacked within a single device footprint. The diffusion structures are arranged in a nested configuration along the vertical axis, with each diffusion structure positioned above or below the other, effectively nesting functional elements within the same lateral space to maximize area utilization.
2Manufacturing precision
If diffusion structure size is reduced to enable further process scaling, then area is reduced, but drive strength deteriorates
Solution Approach 1:
The patent compensates for reduced diffusion structure lateral dimensions by extending the diffusion area into the vertical dimension. Multiple diffusion structures are stacked vertically, so that while each individual diffusion structure becomes smaller to enable further process scaling, the cumulative effective diffusion area is maintained or enhanced through the stacked configuration.
Solution Approach 2:
The patent divides the diffusion structure into multiple segmented regions stacked in series. Instead of relying on a single large diffusion structure, the device uses multiple smaller diffusion structures arranged vertically, where each segment contributes to the overall drive strength. This segmentation allows continued scaling of individual features while maintaining total performance through the combined effect of multiple segments.
3Area of stationary object
If standard-height cells are used for compact design, then area is reduced, but diffusion structure width is insufficient
Solution Approach 1:
The patent resolves the conflict between compact cell area and sufficient diffusion structure width by utilizing the vertical dimension. Multiple diffusion structures are stacked vertically within the standard-height cell, so that the lateral width of each individual diffusion structure can be reduced for compactness, while the effective total diffusion width is maintained through the cumulative effect of multiple vertically-stacked structures.
Data Source
AI summary
Subject matter disclosed herein relates generally to semiconductor devices, and, more particularly, to semiconductor device cell layout.