Dual Fuse Link Configuration for Reliable Blown State
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Solution Overview
Problem
The existing electric fuse technology faces challenges in maintaining a reliable blown state due to re-connection issues, particularly when made from materials prone to electro-migration, and requires improved positioning accuracy and yield in semiconductor devices, especially under advanced reliability and severe conditions.
Innovation Solution
A semiconductor device with two fuse links connected in series, where the first fuse link is made of a copper-containing metal film and the second of a polysilicon film, allowing independent blowing and detection, thereby reducing re-connection ratios and enhancing the hold characteristic by differing current values and geometries.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single fuse link is used in the electric fuse, then the device complexity is low, but the re-connection ratio increases due to electro-migration effects during annealing
Solution Approach 1:
The electric fuse is divided into multiple fuse links (first fuse link and second fuse link) connected in series. Each fuse link can be independently blown by controlling current flow through specific switches. This segmentation reduces the re-connection ratio because the probability of all links re-connecting simultaneously is significantly lower than a single link, thereby improving the hold characteristic.
2Measurement precision
If laser irradiation is used to blow the fuse, then positioning accuracy requirements increase, but the method becomes more complex and costly for new products
Solution Approach 1:
The patent replaces the laser-based mechanical/optical blowing method with an electrical current-based blowing method. By supplying current through the fuse links and controlling switches, the fuse can be blown electrically without requiring precise laser positioning. This substitution eliminates positioning accuracy requirements and simplifies the blowing process.
3Reliability
If a fuse material prone to electro-migration is used, then the conductivity is improved, but the re-connection risk increases during annealing processes
Solution Approach 1:
The fuse is segmented into multiple independent links. Even if one link experiences electro-migration and re-connects during annealing, the other links remain intact and maintain the blown state. This segmentation isolates the harmful electro-migration effect to individual segments, preventing overall re-connection.
Solution Approach 2:
The patent anticipates the harmful effect of electro-migration by designing multiple fuse links in advance. This redundant configuration acts as a cushion against re-connection, ensuring that even if some links are affected by electro-migration, the fuse maintains its blown state through the remaining intact links.
4Reliability
If multiple fuse links are used to reduce re-connection ratio, then the reliability improves, but the manufacturing process becomes more complex
Solution Approach 1:
Multiple fuse links are merged into a single integrated electric fuse structure that can be manufactured in one process. The fuse links share common elements such as the substrate, insulating layers, and switching mechanisms, allowing simultaneous fabrication rather than separate assembly. This merging reduces manufacturing complexity while maintaining the reliability benefits of multiple links.
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 configuration significantly reduces re-connection ratios and improves the hold characteristic of the electric fuse, ensuring accurate detection and reliability even after annealing, using a single power source to independently blow both fuse links without increasing production costs.
Implementation Method 1
blowing the fuse by supplying thereto a predetermined energy of current
Implementation Method 2
a conductor composing the fuse is formed as being folded a plurality of times
Implementation Method 3
if blowing of the electric fuse is followed by annealing
Implementation Method 4
it is anticipated that the portion once blown may be re-connected as being affected by electro-migration of the material
Data Source
AI summary
A semiconductor device is provided including a first fuse link having a copper-containing metal film, a second fuse link having a polysilicon film, a semiconductor substrate, and a field insulating film formed on the semiconductor substrate. The second fuse link is formed on the field insulating film. An interlayer insulating film is provided between the first fuse link and the second fuse link. The first fuse link is electrically connected to the second fuse link via a first plug formed in the interlayer insulating film.