Multi-State E-Fuse Circuit Structure for Non-Destructive Re-Programming
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Solution Overview
Problem
Conventional programmable fuses or anti-fuses are destructive and can only be programmed once, making re-programming impossible, and the use of non-volatile random access memory (NVRAM) increases process complexity and manufacturing costs.
Innovation Solution
A circuit structure for a low power, multiple states electronic fuse (e-fuse) with two short conductor layers and a long conductor layer, where the short layers have high atomic diffusion resistance and the long layer has low atomic diffusion resistance, allowing for non-destructive programming and re-programming by controlling bi-directional electron flow through varying voltage polarity and magnitude at multiple terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional programmable fuses or anti-fuses are used, then the device can be programmed, but the programming is destructive and re-programming is impossible
Solution Approach 1:
The patent applies parameter changes by utilizing voltage polarity reversal to transform the e-fuse from a destructive single-state device to a non-destructive multi-state device. By changing the voltage polarity parameter (positive, negative, or zero), the device can be programmed into different states (0 or 1) and re-programmed multiple times without destruction, directly resolving the contradiction between programming capability and re-programming capability
2Adaptability or versatility
If NVRAM technology is used to enable re-programming, then re-programming capability is achieved, but process complexity and manufacturing costs significantly increase
Solution Approach 1:
The patent employs a simple e-fuse structure using conventional conductor layers (copper, aluminum, or copper alloy) that can be manufactured using existing back-end-of-line metallization processes. This approach avoids the need for complex NVRAM technology while enabling re-programming capability through voltage polarity control, thereby reducing both device complexity and manufacturing costs while maintaining re-programming versatility
3Ease of manufacture
If conventional e-fuse structure is used, then manufacturing is simple, but only single programming state is achievable
Solution Approach 1:
The patent makes the simple e-fuse structure multi-functional by introducing voltage polarity control. The same basic structure (conductor layers with diffusion barrier) can achieve multiple programming states (0 or 1) and support both programming and re-programming operations. This universal approach allows a single device structure to perform multiple functions: single-state programming, multi-state programming, and re-programming, all using conventional manufacturing processes
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
Enables multiple programming states without destructive changes, reducing manufacturing costs and process complexity, and is compatible with existing back-end-of-line metallization processes.
Implementation Method 1
By varying voltage polarity (and magnitude) at the different terminals, bi-directional flow of electrons within the long conductor layer can be selectively controlled
Implementation Method 2
The short conductor layers can have a relatively high atomic diffusion resistance (i.e., can exhibit low atomic diffusivity) and the long conductor layer can have a relatively low atomic diffusion resistance (i.e., can exhibit high atomic diffusivity)
Data Source
AI summary
In one embodiment of an e-fuse programming/re-programming circuit, the e-fuse has two short high atomic diffusion resistance conductor layers positioned on opposite sides and at a same end of a long low atomic diffusion resistance conductor layer. A voltage source is used to vary the polarity and, optionally, the magnitude of voltage applied to the terminals in order to control bi-directional flow of electrons within the long conductor layer and, thereby formation of opens and/or shorts at the long conductor layer-short conductor layer interfaces. The formation of such opens and/or shorts can be used to achieve different programming states. Other circuit structure embodiments incorporate e-fuses with additional conductor layers and additional terminals so as to allow for even more programming states. Also disclosed are embodiments of associated e-fuse programming and re-programming methods.