Series Fuse Link Segmentation for Electromigration Reliability
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Solution Overview
Problem
Electrical fuses and antifuses in semiconductor devices can reconnection or redisconnect due to electromigration during heat treatment, leading to unreliable state maintenance, especially under high accuracy or severe conditions.
Innovation Solution
A semiconductor device design with two state-changing portions connected in series or parallel, each with independent current or voltage terminals, and a decision unit to ensure both are disconnected or connected, reducing reconnection/redisconnection probability by detecting the state of each portion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single fuse link is used for disconnection, then the device structure is simple, but the reliability is low due to possible reconnection after heat treatment
Solution Approach 1:
The fuse is divided into multiple independent fuse links (first fuse link and second fuse link) connected in series. Each fuse link can be independently disconnected by applying voltage across its respective terminals. This segmentation ensures that even if one link reconnects due to electromigration, the other links maintain the disconnected state, thereby improving overall reliability without requiring a completely complex structural redesign.
Solution Approach 2:
The patent implements a decision unit that detects the connection state of each fuse link before final disconnection is confirmed. This preliminary detection acts as a cushioning mechanism to identify and address potential reconnection issues before they compromise the overall fuse functionality, ensuring reliable disconnection state maintenance after heat treatment.
2Ease of manufacture
If heat treatment is applied to the semiconductor device, then manufacturing processes are completed, but electromigration may cause fuse reconnection
Solution Approach 1:
By segmenting the fuse into multiple independent links with separate terminals, the patent allows heat treatment to be applied without causing simultaneous electromigration effects on all links. The independent structure means that thermal and electrical stresses are distributed, reducing the probability that all links will reconnect after heat treatment.
Solution Approach 2:
The decision unit provides feedback detection of the connection state of each fuse link. This feedback mechanism monitors the effect of heat treatment on fuse links and can detect any reconnection that occurs during or after the manufacturing process, allowing for quality control and reliability verification.
3Reliability
If multiple fuse links are used to reduce reconnection probability, then reliability improves, but device complexity increases
Solution Approach 1:
The fuse is segmented into exactly two fuse links, which is the minimum number needed to reduce reconnection probability while avoiding excessive complexity. Each link has its own terminals for independent voltage application and state detection, providing a balanced solution between reliability improvement and structural simplicity.
Solution Approach 2:
The decision unit serves multiple functions: it detects the connection state of each fuse link individually, determines the overall fuse state, and provides feedback for quality control. This multi-functionality reduces the need for separate detection circuits for each link, thereby limiting the increase in device complexity while maintaining improved reliability.
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 design significantly reduces the probability of reconnection/redisconnection, enhancing the reliability of semiconductor devices by ensuring both state-changing portions are properly disconnected or connected, even after heat treatment.
Implementation Method 1
disconnecting the first fuse link and the second fuse link respectively by respectively applying a voltage
Implementation Method 2
the electrical fuse may be reconnected at the disconnected position. In the case where the electrical fuse is constituted of a material susceptible to electromigration, the material may migrate because of the electromigration when the semiconductor device is subjected to the heat treatment after the disconnection of the electrical fuse
Data Source
AI summary
A semiconductor device includes a semiconductor substrate, and an electrical fuse provided on the semiconductor substrates. The electrical fuse includes a first fuse link and a second fuse link mutually connected in series, a first current inlet/outlet terminal (first terminal) and a second current inlet/outlet terminal (second terminal) respectively provided at an end and the other end of the first fuse link, and a third current inlet/outlet terminal (second terminal) and a fourth current inlet/outlet terminal (third terminal) provided at an end and the other end of the second fuse link.