Semiconductor Fuse Moisture Barrier via Silicon Nitride Film
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Solution Overview
Problem
Moisture ingress through the fuse opening in semiconductor devices with silicon fuses can impair reliability and degrade properties over time, despite conventional measures like guard rings, as the interface between insulating films and guard rings can act as a moisture transfer path.
Innovation Solution
A semiconductor device design that includes a silicon nitride film covering the interface between the interlayer insulating film and the metal wiring guard ring, along with a final protection film, to prevent moisture transfer from the fuse opening to the outside of the guard ring, ensuring the interlayer insulating film is not exposed and using a combination of insulating films like BPSG and SOG to reduce moisture pathways.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fuse opening is formed by making the insulating film thinner above the silicon fuse, then the fuse can be disconnected for programming and redundancy functions, but moisture can enter through the fuse opening and transfer along the interface between insulating films and guard rings, degrading reliability over time
Solution Approach 1:
The patent extends the protection from a two-dimensional surface layer to a three-dimensional structure by forming a protruding protective film that rises above the fuse opening. This vertical extension creates a physical barrier that blocks moisture transfer paths that would otherwise travel along the interface between insulating films and guard rings at the device surface.
Solution Approach 2:
The protective film is formed before final device assembly and testing, establishing a moisture barrier in advance. This preliminary protective structure prevents moisture ingress during subsequent storage, handling, and operation, addressing the reliability issue before it can manifest as actual damage.
2Reliability
If a guard ring is provided around the silicon fuse to prevent moisture ingress, then reliability can be improved, but the interface between insulating films and the guard ring creates moisture transfer paths that can still allow moisture to reach internal circuits
Solution Approach 1:
The patent uses a thin film-based protective structure that conforms to the existing device geometry. This flexible film approach provides effective moisture blocking without requiring bulky additional components or complex multi-layer structures, thus improving reliability while minimizing increases in device complexity.
3Reliability
If multiple guard ring structures and interlayer insulating films are used to block moisture paths, then moisture protection can be enhanced, but the interface regions between these layers create additional moisture transfer pathways
Solution Approach 1:
The protective film acts as an intermediary barrier between the fuse opening and the guard ring structure. By positioning this film to protrude above the fuse opening and extend toward the guard ring, it creates an intermediate protective zone that blocks moisture before it can reach the problematic interface regions between insulating films and guard rings.
Data Source
AI summary
A semiconductor device includes a base insulating film on which a silicon fuse, silicon wiring patterns, and a silicon guard ring are formed. The silicon guard ring surrounds the silicon fuse and has silicon cutout parts so as not to contact the silicon wiring patterns. A via guard ring, which has via cutout parts located above the silicon cutout parts, is formed in an interlayer insulating film and on the silicon guard ring. A metal wiring guard ring is formed on the via guard ring and the interlayer insulating film. A silicon nitride film is formed on the interlayer insulating film so as to cover the metal wiring guard ring. An interface between the interlayer insulating film and the metal wiring guard ring at the via cutout parts is covered by the silicon nitride film.