1T2R1T eFuse Cell Layout with Shared Fuse Wings
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing 1T1R eFuse architecture in integrated circuit chips faces challenges in reducing the overall area of the eFuse array due to strict design rule constraints in the metal 2 layer, leading to increased resistance in the programming path and reduced programming current.
Innovation Solution
The 1T2R1T layout is introduced, where adjacent eFuse elements share common fuse wings in the metal 2 layer, reducing parasitic resistance and allowing for a 15-20% reduction in cell area, thereby increasing the programming current by optimizing the fuse structure and connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of moving object
If the fuse element size is reduced to decrease cell area, then the eFuse area is reduced, but the design rule constraints in metal 2 layer prevent further reduction
Solution Approach 1:
Adjacent eFuse elements share common fuse wings, merging previously duplicate structures into shared resources. This allows the cell area to be reduced by eliminating redundant metal 2 layer structures while maintaining design rule compliance, as the shared fuse wings serve multiple adjacent cells simultaneously.
Solution Approach 2:
The common fuse wings serve multiple functions: they act as fuse elements for one cell and shared structural elements for adjacent cells. This multi-functionality reduces the overall area requirement while ensuring that all cells meet the minimum design rule constraints for metal 2 layer structures.
2Reliability
If fuse elements are placed in metal 2 layer to meet design rules, then manufacturing compliance is achieved, but parasitic resistance increases and programming current decreases
Solution Approach 1:
By merging adjacent fuse elements into shared common fuse wings in the metal 2 layer, the total length of metal 2 layer paths is reduced. This decreases the parasitic resistance associated with the fuse structure while maintaining all required design rule clearances and specifications.
Solution Approach 2:
The shared common fuse wings act as intermediary structures that reduce the overall resistance path. By serving as shared connections between adjacent cells, they eliminate redundant metal 2 layer segments and reduce the cumulative parasitic resistance affecting programming current.
3Area of moving object
If adjacent eFuse elements share common fuse wings, then cell area is reduced by 15-20%, but the layout complexity increases
Solution Approach 1:
The layout complexity is managed by systematically merging adjacent fuse elements into shared common fuse wings. While the structural organization becomes more intricate, the area reduction of 15-20% is achieved through this organized sharing pattern, where each common fuse wing clearly serves specific adjacent cells.
Data Source
AI summary
An integrated circuit structure includes a first fuse line formed in a first metal layer; a second fuse line formed in the first metal layer; a first pair of fuse wings formed in the first metal layer on opposite sides of a first end of the first fuse line; a second pair of fuse wings formed in the first metal layer on opposites sides of a first end of the second fuse line; a third pair of fuse wings formed in the first metal layer on opposite sides of a second end of the first fuse line; and a fourth pair of fuse wings formed in the first metal layer on opposites sides of a second end of the second fuse line. The first and second pairs of fuse wings share a first common fuse wing and the third and fourth pairs of wings share a second common fuse wing.