Programmable Metal Fuse Structure for Low-Current Programming
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Solution Overview
Problem
Conventional one-time programmable cell structures in semiconductor dice require high voltage and high programming current, leading to increased power consumption, complexity, and cost, particularly due to the use of gate oxide breakdown and hot carrier injection or silicide and interconnect metal fuses.
Innovation Solution
A method for forming a one-time programmable metal fuse structure using a gate metal fuse with a high-k dielectric layer and polysilicon segments, which can be programmed with a small current, reducing the need for additional masks and processing steps, especially suitable for advanced process technologies like 32.0 nm or 28.0 nm technologies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If gate oxide breakdown and hot carrier injection are used for programming, then programmability is achieved, but high voltage is required which increases power consumption and complexity
Solution Approach 1:
The patent changes the programming mechanism from high-voltage-based (gate oxide breakdown, hot carrier injection) to low-current-based (metal fuse breakdown). This parameter change in the programming approach allows achieving programmability without requiring high voltage, thereby reducing power consumption and eliminating the need for charge pump circuitry.
2Reliability
If silicide and interconnect metal fuses are used for programming, then programmability is achieved, but high programming current is required which increases power consumption
Solution Approach 1:
The patent employs a metal fuse structure with specific material composition and geometry that enables programming at low current levels. The fuse is formed from a metal layer integrated into the gate structure, and its dimensions and material properties are optimized to achieve breakdown at low programming current, thus resolving the contradiction between programmability and programming current requirements.
3Reliability
If conventional fuse structures are used, then programmability is achieved, but additional masks and processing steps are required which increase complexity and cost
Solution Approach 1:
The patent merges the fuse structure with the gate metal layer, forming the fuse as an integral part of the gate structure rather than as a separate component. This integration eliminates the need for additional masks and processing steps that would be required for conventional fuse structures, thereby reducing device complexity and manufacturing cost while maintaining programmability.
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 programming with a very small programming current, reducing power consumption and processing costs, while maintaining high reliability and minimizing residue impact on neighboring areas, and is compatible with high-k metal gate processes.
Implementation Method 1
a method for forming a one-time programmable metal fuse structure... programmed with a small current
Data Source
AI summary
According to one exemplary embodiment, a method for forming a one-time programmable metal fuse structure includes forming a metal fuse structure over a substrate, the metal fuse structure including a gate metal segment situated between a dielectric segment and a polysilicon segment, a gate metal fuse being formed in a portion of the gate metal segment. The method further includes doping the polysilicon segment so as to form first and second doped polysilicon portions separated by an undoped polysilicon portion where, in one embodiment, the gate metal fuse is substantially co-extensive with the undoped polysilicon portion. The method can further include forming a first silicide segment on the first doped polysilicon portion and a second silicide segment on the second doped polysilicon portion, where the first and second silicide segments form respective terminals of the one-time programmable metal fuse structure.