Backside Power Islands for Mixed-Height Cell Power Routing
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Solution Overview
Problem
In semiconductor technology, the small side-by-side space between backside power rails poses challenges for mixed cell heights and high overlay requirements, particularly in CMOS device structures with 6T and 9T cells, where achieving precise power distribution is difficult due to the tight spacing and varying cell heights.
Innovation Solution
The use of backside power islands instead of power rails, with islands in different device tracks isolated by cut regions, allows for a structure with mixed cell heights and small side-by-side space, enabling efficient power distribution through a network of electrically conductive islands and interconnect dielectric material layers.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If backside power rails are used to provide power connections, then power distribution is achieved, but the side-by-side space becomes very small and overlay requirements become very high
Solution Approach 1:
The continuous backside power rail is segmented into discrete backside power islands. Each power island is separated from adjacent power islands by cut regions, transforming the monolithic power distribution structure into modular units. This segmentation reduces the side-by-side space constraints and relaxes overlay requirements while maintaining power distribution functionality through the array of distributed power islands.
2Reliability
If backside power rails are used for power connection, then power supply is provided, but the structure cannot accommodate mixed cell heights effectively
Solution Approach 1:
The power distribution network is divided into discrete power islands that can be independently configured. This segmentation allows different device tracks to have power islands positioned and sized according to their specific height requirements, enabling 6T cells and 9T cells to coexist in the same semiconductor structure without compromising power supply reliability.
Solution Approach 2:
Different regions of the semiconductor structure can have power islands with different characteristics (size, position, configuration) tailored to local requirements. Device tracks with different cell heights can access power islands optimized for their specific needs, providing local adaptability while maintaining overall power supply reliability.
3Area of stationary object
If small side-by-side space is used between power connections, then area is reduced, but manufacturing precision requirements become very high
Solution Approach 1:
The compact power distribution is achieved through segmented power islands rather than continuous rails. The cut regions between power islands provide manufacturing tolerance buffer zones, allowing smaller side-by-side spacing between power structures while maintaining acceptable overlay requirements. The discrete nature of power islands enables precise positioning independent of adjacent structures.
Data Source
AI summary
A semiconductor structure is provided that includes a plurality of backside power islands, rather than backside power rails. The backside power islands are present in a first device track and a second device track. Each backside power island located in the first device track and the second device track are isolated by a first cut region, and the backside power islands that are located in the first device track are separated from the backside power islands located in the second device track by a second cut region. The second cut region is oriented perpendicular to the first cut region.