E-fuse Cell Shunt Path ESD Protection
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Solution Overview
Problem
E-fuses in semiconductor devices are susceptible to accidental programming and electrical overstress, such as electrostatic discharge (ESD), leading to reliability issues and reduced production yield due to their small and fragile physical structure.
Innovation Solution
The implementation of an e-fuse cell with a selectively activated shunt path and a diode in parallel to the e-fuse, which detects and responds to electrical overstress events by diverting excessive currents, providing protection against ESD and preventing false programming.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If e-fuses are designed with small physical structure to allow high density integration, then the quantity of e-fuses per chip increases, but the e-fuses become sensitive to electrical static discharge and floating supply voltage causing false programming
Solution Approach 1:
A diode is introduced as an intermediary protective element connected in parallel with the e-fuse. The diode acts as a mediator that captures and redirects electrical overstress events (such as electrostatic discharge or floating supply voltage) away from the e-fuse, preventing false programming while allowing the e-fuse to maintain its small, high-density structure
Solution Approach 2:
The diode provides beforehand protection by being pre-positioned in parallel with the e-fuse to capture potential electrical overstress events before they can reach and damage the e-fuse. This prior cushioning mechanism ensures that when ESD or floating voltage occurs, the diode has already been in place to divert the harmful energy
2Use of energy by moving object
If e-fuses are made with low resistance for efficient operation, then power consumption decreases, but the e-fuses become more vulnerable to electrical overstress and false programming
Solution Approach 1:
The diode serves as a protective intermediary that shields the low-resistance e-fuse from electrical overstress. By placing the diode in parallel, it creates a preferential path for ESD current, allowing the e-fuse to maintain its low resistance for efficient operation while the diode handles the harmful electrical events
3Reliability
If additional protection circuitry is added to e-fuses, then reliability against electrical overstress improves, but device complexity increases
Solution Approach 1:
The diode is a simple, inexpensive, and compact component that provides effective ESD protection without adding significant complexity. It acts as a disposable protective element that can be easily integrated into the e-fuse structure, offering robust protection while maintaining overall device simplicity and manufacturability
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 solution effectively protects e-fuses from damage caused by electrical overstress, ensuring reliable operation and increased production yield by preventing unintended changes in the e-fuse resistance state during manufacturing and testing.
Implementation Method 1
a diode connected to the source node and the ground in parallel to the e-fuse to inhibit negative current flow across the e-fuse
Implementation Method 2
a selectively activated shunt path from the source node to the ground... a device for activating the shunt path in response to an electrical overstress event
Data Source
AI summary
E-fuse cells and methods for protecting e-fuses are provided. An exemplary e-fuse cell includes an e-fuse having a first end coupled to a source node and a second end selectively coupled to a ground. Further, the exemplary e-fuse includes a selectively activated shunt path from the source node to the ground. Also, the exemplary e-fuse includes a device for activating the shunt path in response to an electrical overstress event.