STI Fuse Structure for Low-Voltage Backup Unit Activation
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Solution Overview
Problem
Current fuses used in memory devices for activating backup units suffer from inefficiencies due to high blowing voltages and process variations, leading to inaccurate conversions and reduced efficiency.
Innovation Solution
A fuse element with a shallow trench isolation (STI) structure and a drain region configured to receive a stress voltage, establishing a conductive path from the drain to the source region, allowing the fuse to be blown at a lower stress signal without requiring a gate voltage, thereby activating the backup unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fuses are used to activate backup units, then the backup unit can be converted to a normal circuit, but the blowing voltage is extremely high and blowing efficiency decreases due to process variation
Solution Approach 1:
The patent changes the physical parameters of the fuse structure by introducing a shallow trench isolation (STI) structure surrounding the active area and configuring the drain region to receive stress voltage. This structural parameter change enables the fuse to operate at lower voltages while maintaining reliable blowing efficiency despite process variations.
2Ease of manufacture
If conventional fuses are used to activate backup units, then the backup unit can be converted to a normal circuit, but the fuse requires extremely high voltage to blow
Solution Approach 1:
The patent modifies the fuse structure parameters by incorporating an STI structure and configuring the drain region to receive stress voltage, which changes the electrical characteristics to enable lower voltage operation while maintaining ease of manufacture through standard semiconductor fabrication processes.
Solution Approach 2:
The patent replaces the conventional fuse structure with a PMOS-like transistor structure where the channel is formed between source and drain regions, and the STI structure acts as the isolation medium. This substitution allows the fuse to be controlled by electric field effects rather than requiring extreme voltage breakdown.
3Productivity
If conventional fuses are used, then backup units can be activated, but the fuse structure occupies larger area and has reduced efficiency
Solution Approach 1:
The patent designs the fuse element to share structural similarities with PMOS transistors, allowing it to utilize the same fabrication processes and layout techniques. This multi-functionality approach enables the fuse to achieve compact area while maintaining efficient activation through the stress voltage mechanism.
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 enables a stable and efficient activation of backup units with reduced area requirements and lower stress signals compared to conventional fuses, ensuring reliable operation even without external gate voltage.
Implementation Method 1
accumulating electrons in a portion of the STI structure adjacent to the drain region
Implementation Method 2
generating a conductive path through the drain region and the source region so that the fuse element is conductive
Data Source
AI summary
A method for activating a backup unit includes providing a fuse element connected to the backup unit. The fuse element includes an active area, which includes a source region and a drain region beside the source region, a gate region disposed on the active area, and a shallow trench isolation (STI) structure surrounding the active area. The method also includes applying a stress voltage on the drain region of the fuse element; accumulating electrons in a portion of the STI structure adjacent to the drain region; generating a conductive path through the drain region and the source region so that the fuse element is conductive; and activating the backup unit through the fuse element.