Fuse Crack Stop Void with Fixed Passivation
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Solution Overview
Problem
The use of low-k dielectric materials in integrated circuits leads to reliability and yield issues due to the susceptibility of fuses to damage during laser blow operations, as they are formed in the same inter-level dielectric layer as interconnects, resulting in separation and exposure to the environment, which can cause corrosion and increase electrical resistance.
Innovation Solution
A method is introduced to form fuses in a low-k or silicon oxide dielectric layer with minimal distances by creating a material-free region, or void, between adjacent fuses, which prevents crack propagation during fuse blow operations, using a pattern-conformal aluminum fuse over-plate to define the interfuse crack stop and ensure consistent passivation coverage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fuses are formed in low-k dielectric layer with minimal spacing, then productivity and area utilization are improved, but reliability deteriorates due to crack propagation during laser blow operations
Solution Approach 1:
The dielectric layer is segmented into multiple sections: a first section covering the fuse and a second section removed to form a void between adjacent fuses. This segmentation prevents crack propagation from one fuse to another during laser blow operations, enabling minimal fuse spacing while maintaining reliability.
Solution Approach 2:
Material is extracted from the dielectric layer between adjacent fuses to create voids. This removal of material prevents crack propagation pathways, allowing fuses to be placed at minimal distances without compromising programming accuracy.
2Ease of manufacture
If conventional fuse structures are used in low-k dielectric, then manufacturing simplicity is maintained, but reliability deteriorates due to material layer separation under physical stress
Solution Approach 1:
The dielectric layer is divided into regions that remain over the fuse and regions removed between fuses. This segmentation prevents delamination and maintains dielectric integrity under physical stress while keeping the manufacturing process straightforward.
3Area of stationary object
If minimal distance between fuses is used, then area utilization is improved, but manufacturing precision deteriorates due to difficulty in maintaining consistent passivation coverage
Solution Approach 1:
The passivation structure is segmented to provide coverage only where needed (over the fuse) while leaving voids between fuses. This segmentation enables minimal fuse spacing while maintaining precise and consistent passivation coverage through standard deposition processes.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances the reliability and yield of fuse structures by preventing damage propagation between fuses, allowing for tighter fuse spacing without increasing layout footprint, and maintaining consistent passivation coverage, thus reducing the risk of incorrect programming and environmental exposure.
Implementation Method 1
Fuses may be selectively blown or programmed with a laser beam. The laser beam imparts enough energy into the fuse to melt the metal.
Implementation Method 2
the laser beam imparts enough energy into the fuse to melt the metal
Implementation Method 3
creating a material-free region, or void, between adjacent fuses, which prevents crack propagation during fuse blow operations
Data Source
AI summary
A crack stop void is formed in a low-k dielectric or silicon oxide layer between adjacent fuse structures for preventing propagation of cracks between the adjacent fuse structures during a fuse blow operation. The passivation layer is fixed in place by using an etch stop shape of conducting material which is formed simultaneously with the formation of the interconnect structure. This produces a reliable and repeatable fuse structure that has controllable passivation layer over the fuse structure that is easily manufactured.