Polysilicon e-Fuse Structure With Metal Heater for Lower Programming Current
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Solution Overview
Problem
Polysilicon e-fuses in integrated circuits occupy a large footprint due to the size of the fuse body and the associated current source needed for programming, and existing heating approaches are ineffective in delivering sufficient heat to reduce the current required for programming.
Innovation Solution
A fuse structure comprising a polysilicon fuse body with a metal heater and a heat spreading structure thermally coupled to the metal heater, which extends horizontally adjacent to the fuse body, reducing the necessary programming energy and the size of the programming current source without requiring additional masks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If current heating approaches are used to heat the fuse body, then the fuse body temperature increases, but the heat delivery is insufficient to reduce the programming current requirement
Solution Approach 1:
A metal heater layer is introduced as an intermediary component between the fuse body and the heating current source. This metal heater has superior electrical conductivity and thermal properties compared to the polysilicon fuse body, allowing it to efficiently convert electrical energy to heat and transfer that heat to the fuse body, thereby reducing the programming current requirement.
Solution Approach 2:
The invention changes the material parameter of the heating element from polysilicon (fuse body material) to metal (heater material). This parameter change improves the electrical conductivity and heat generation efficiency, enabling sufficient heat delivery to the fuse body with lower programming current.
2Reliability
If a large current source is used to program the polysilicon fuse, then the fuse can be programmed, but the footprint of the current source increases
Solution Approach 1:
The metal heater acts as a mediator that amplifies the heating efficiency. By placing a highly conductive metal layer over the fuse body and applying current through this metal heater, the system achieves better heat transfer with lower current requirements, thereby reducing the size of the current source needed for reliable fuse programming.
3Area of stationary object
If the fuse body size is reduced to decrease footprint, then the footprint decreases, but the heat delivery to the fuse body becomes insufficient
Solution Approach 1:
The heating function is segmented from the fuse body structure. Instead of relying on the fuse body material itself to generate and transfer heat efficiently, a separate metal heater layer is introduced that specializes in heat generation and transfer, allowing the fuse body to be miniaturized while maintaining sufficient heat delivery through the dedicated heater component.
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 reduces the programming energy and current source size, minimizing the circuitry footprint while efficiently delivering heat to the fuse body, thereby improving the programming efficiency of polysilicon e-fuses in integrated circuits.
Implementation Method 1
a metal heater above the fuse body... heating an area over the fuse body using a metal heater
Implementation Method 2
a heat spreading structure thermally coupled to the metal heater and extending horizontally adjacent to at least one side of the fuse body... spreading heat from the metal heater through a heat spreading structure thermally coupled to the metal heater
Data Source
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AI summary
A fuse structure includes a fuse body including a polysilicon, and a metal heater over the fuse body. The fuse structure also includes a heating spreading structure thermally coupled to the metal heater and extending horizontally adjacent to at least one side of the fuse body. The metal heater can be a portion of a metal wire or a resistor including a resistive metal. The heat spreading structure may include a plurality of metal contacts.