Fuse Structure Design for Reduced Resistance via Multi-Layer Coupling
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Solution Overview
Problem
One-dimensional metal process design rules restrict the line width of fuse structures in semiconductor devices, limiting the programmability by maintaining equal line widths for the anode and cathode ends, which reduces the fuse structure's resistance and programmability compared to designs allowing wider line widths.
Innovation Solution
A fuse structure design with wider line widths on the anode and cathode ends compared to the fuse link, while adhering to 1-D metal process design rules, by using parallel lines in adjacent conductive layers to reduce resistance through strategic coupling, allowing for increased programming current.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If equal line widths are maintained for anode and cathode ends according to 1-D metal process design rules, then manufacturing compliance is achieved, but resistance is increased and programmability is reduced
Solution Approach 1:
The patent transitions from a one-dimensional metal process to a two-dimensional approach by using multiple conductive layers. The anode end utilizes a first conductive layer while the cathode end utilizes a second conductive layer, allowing different effective line widths in the vertical dimension while maintaining compliance with 1-D process rules in the planar dimension.
Solution Approach 2:
The patent combines multiple conductive layers (first conductive layer and second conductive layer) to create effective wider line widths at the anode and cathode ends. By merging the conductive paths through vertical coupling, the structure achieves reduced resistance without violating 1-D metal process design rules.
2Reliability
If wider line widths are used at anode and cathode ends compared to fuse link, then resistance is reduced and programmability is improved, but 1-D metal process design rules are violated
Solution Approach 1:
The patent resolves the contradiction by moving the line width variation into the vertical dimension through multiple conductive layers. The wider effective line widths are achieved by stacking conductive layers rather than expanding in the planar dimension, thus maintaining compliance with 1-D process rules.
Solution Approach 2:
The patent applies different line width characteristics to different parts of the fuse structure: the anode end has wider effective width through the first conductive layer, the cathode end has wider effective width through the second conductive layer, and the fuse link maintains narrower width. This local differentiation optimizes resistance without uniform expansion.
3Device complexity
If equal line widths are used throughout the fuse line, then manufacturing simplicity is maintained, but programming current is limited
Solution Approach 1:
The patent merges multiple conductive layers at the anode and cathode ends to reduce resistance and increase programming current capability, while maintaining uniform single-layer structure in the fuse link region, thus balancing complexity and power requirements.
Solution Approach 2:
The fuse line is segmented into different structural regions: the anode end with first conductive layer, the cathode end with second conductive layer, and the fuse link with uniform structure. This segmentation allows optimized electrical characteristics in different regions without requiring complete structural redesign.
Data Source
AI summary
A fuse structure comprises a first conductive layer on a first level. The first conductive layer comprises a fuse line extending in a first direction. The fuse line has a first end portion, a second end portion opposite the first end portion, and a fuse link portion connecting the first end portion and the second end portion. The first conductive layer also comprises lines parallel to the fuse line, the lines being aligned in the first direction and being separated from one another by a first distance measured in the first direction. The fuse structure also comprises a second conductive layer on a second level different from the first level and coupled with the first conductive layer. The second conductive layer has parallel lines extending in a second direction, the parallel lines being separated by a second distance measured in a third direction orthogonal to the second direction.