Semiconductor Fuse Barrier Pattern for Laser Repair
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Solution Overview
Problem
Conventional semiconductor memory devices face challenges in precisely and completely blowing fuses due to the thickness of the inter-metallic dielectric layer, which can lead to residue and electrical shorting between adjacent fuses, especially as integration density increases and the distance between fuses decreases.
Innovation Solution
The implementation of fuse barrier patterns between adjacent fuses, formed as a multi-layered structure of the same materials as the inter-metallic dielectric and passivation layers, to protect non-selected fuses from damage during the laser-based fuse blowing process, ensuring safe and complete opening of selected fuses without causing electrical shorting.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the inter-metallic dielectric layer thickness is increased to ensure complete fuse opening, then fuse blowing completeness is improved, but adjacent fuses are damaged by high energy laser beam
Solution Approach 1:
A barrier layer is introduced between adjacent fuses as an intermediary structure. This barrier layer absorbs or blocks the laser energy that would otherwise damage adjacent fuses, while allowing the selected fuse to be completely opened. The barrier layer acts as a mediator that protects non-selected fuses from the harmful effects of high-energy laser exposure.
Solution Approach 2:
The dielectric structure is segmented into multiple layers: the inter-metallic dielectric layer and the barrier layer with different material compositions and thicknesses. This segmentation allows each layer to perform its specific function - the inter-metallic dielectric layer provides electrical isolation, while the barrier layer provides laser protection - thereby resolving the contradiction between complete fuse opening and adjacent fuse protection.
2Measurement precision
If the inter-metallic dielectric layer thickness is decreased to enable precise fuse blowing, then laser beam precision is improved, but fuse residue remains at bottom sidewalls
Solution Approach 1:
The dielectric structure uses composite materials with different properties at different locations. The barrier layer is formed with materials having different etch selectivity and laser absorption characteristics compared to the inter-metallic dielectric layer. This composite structure enables precise laser focusing on the selected fuse while preventing residue formation, as the barrier layer materials are designed to be fully removed or protected during the blowing process.
3Ease of operation
If continuous etching is performed to expose fuse top surfaces, then fuse accessibility is improved, but broken fuse pieces adhere to adjacent fuses causing shorting
Solution Approach 1:
The barrier layer is selectively removed or patterned in specific regions to extract only the necessary portions for fuse accessibility while retaining the protective function in other areas. This selective extraction allows laser access to the selected fuse for complete opening while maintaining the barrier function that prevents broken fuse pieces from adhering to adjacent fuses, thereby preserving electrical isolation.
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
The fuse barrier patterns effectively prevent damage to adjacent fuses during the laser-based repair process, ensuring complete and safe opening of fuses, reducing the risk of electrical shorting and improving the yield of functioning chips, while also simplifying the fabrication process.
Implementation Method 1
a fuse blowing step that employs a laser beam in order to reassign the failing cells with the new addresses of the redundant cells
Implementation Method 2
it can be difficult to completely blow, or open, the fuse to be opened
Implementation Method 3
the energy of the laser beam is increased to a higher level in order to ensure complete opening of the fuse
Data Source
AI summary
In a semiconductor device having a plurality of fuses and a method of fabricating the same, the semiconductor device comprises an inter-layer dielectric layer on a semiconductor substrate; a plurality of fuses on the inter-layer dielectric layer, an inter-metallic dielectric layer on the plurality of fuses and the inter-layer dielectric layer, a passivation layer on the inter-metallic dielectric layer, fuse windows exposing portions of a top surface and sidewall surfaces of the plurality of fuses, and a fuse barrier pattern between adjacent ones of the plurality of the fuses.