Empty Vias for Electromigration in E-Fuse Re-Programming
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Solution Overview
Problem
Electromigration in metal interconnects during e-fuse re-programming leads to dielectric breakdown and reliability concerns due to metal extrusion and crack propagation in conventional e-fuse structures.
Innovation Solution
The formation of empty vias in an interlayer dielectric allows for controlled electromigration during e-fuse re-programming, preventing dielectric breakdown by creating localized voids and metal extrusion spaces adjacent to interconnect wires.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If electromigration is used in metal interconnects to induce an electrical open during e-fuse programming, then the e-fuse can be re-programmed, but metal extrusion causes dielectric breakdown, intra-level shorting, and crack propagation leading to reliability concerns
Solution Approach 1:
The patent extracts the harmful metal extrusion from the dielectric layer by creating empty vias that serve as dedicated receptacles for the extruded metal. This separates the electromigration function from the dielectric integrity, allowing re-programming without compromising reliability.
Solution Approach 2:
The patent converts the harmful metal extrusion effect into a beneficial feature by directing it into empty vias. The metal extrusion, which would normally cause dielectric breakdown and shorting, is instead channeled into predetermined empty spaces, preventing damage while maintaining the electromigration-based re-programming capability.
2Ease of operation
If a high current pulse is passed through the silicided gate to cause damage on the silicide layer, then the resistance increases for programming, but the process is challenging and complex
Solution Approach 1:
The patent replaces the mechanical/silicided gate structure with a pure metal interconnect electromigration mechanism. This substitution simplifies the fuse structure by eliminating the silicided gate while achieving the same programming function through controlled metal migration, making the process more manageable in advanced technologies.
3Reliability
If empty vias are created to accommodate metal extrusion, then dielectric breakdown is prevented, but the device structure becomes more complex
Solution Approach 1:
The patent applies preliminary action by creating empty vias during the initial fabrication process, before electromigration occurs. This preemptive preparation ensures that when metal extrusion happens during re-programming, the empty vias are already in place to receive the extruded metal, preventing dielectric breakdown without requiring additional processing steps later.
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 of e-fuse devices by avoiding dielectric breakdown and crack propagation, ensuring stable resistance changes during programming and re-programming processes.
Implementation Method 1
electromigration induces atom drift in the direction of electron current flow, causing a void at the cathode end and metal extrusion at the anode end
Data Source
AI summary
The disclosure relates generally to integrated circuit (IC) chip fabrication, and more particularly, to an e-fuse device including an opening, a first via and a second via in an interlayer dielectric, wherein the opening, the first via and the second via are connected to an interconnect below the interlayer dielectric; a dielectric layer that encloses the first via and the second via; and a metal layer over the dielectric layer, wherein the metal layer fills the opening with a metal, and wherein the first via and the second via are substantially empty to allow for electromigration of the interconnect during re-programming of the e-fuse device.