E-Fuse Detection Circuit Using Junction Breakdown for High Current Rupture
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Solution Overview
Problem
In semiconductor integrated circuits, existing E-fuse detection circuits face challenges in efficiently rupturing E-fuses due to the need for high currents, which is difficult to achieve without increasing the voltage beyond pumping voltage limits or enlarging the switching transistor within limited space.
Innovation Solution
The proposed solution involves an E-fuse detection circuit with a low resistance unit, such as a MOS transistor, that can be broken down to provide a low resistance path, allowing high currents to flow between voltage sources without increasing the switching unit's area or voltage beyond pumping limits, enabling selective rupture and detection of the E-fuse.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the voltage level of the first voltage source is raised to increase current, then the current for rupturing the E-fuse is sufficient, but the voltage exceeds the pumping voltage limit
Solution Approach 1:
The circuit is segmented into multiple functional blocks: a first voltage source for providing high voltage, a second voltage source for providing low voltage, a switching unit controlled by control signals, and a low resistance unit. This segmentation allows the high voltage to be applied only when needed for fuse rupture while maintaining normal operating voltage levels during detection, thus resolving the contradiction between requiring high current for rupture and exceeding voltage limits during normal operation.
2Power
If the area of the switching transistor is increased to reduce resistance, then the current for rupturing the E-fuse is sufficient, but the layout space is exceeded
Solution Approach 1:
The switching unit dynamically changes the resistance characteristics of the circuit based on the state of the E-fuse. When the E-fuse is intact, the switching unit operates in a high-resistance state during detection. When rupture is desired, the switching unit switches to a low-resistance state to allow high current flow. This dynamic operation eliminates the need for a permanently large switching transistor, thus resolving the contradiction between sufficient rupture current and layout space.
3Reliability
If a high current is applied to rupture the E-fuse, then the fuse is successfully ruptured, but the detection precision is affected by current magnitude variations
Solution Approach 1:
The circuit performs periodic operations: first applying a detection current to check if the E-fuse is ruptured, then if needed, applying a high rupture current through the switching unit. The control unit manages this periodic sequence, ensuring that detection and rupture operations are separated in time. This periodic action allows precise detection without the interference of high current variations, resolving the contradiction between reliable fuse rupture and detection precision.
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
This approach allows for efficient rupture and detection of E-fuses with high currents, eliminating the need for increased transistor area or excessive voltage, thereby improving layout efficiency and reducing current requirements for fuse cutting detection.
Implementation Method 1
a low resistance unit coupled to the electric fuse and having a junction which is broken down
Implementation Method 2
a programming current is applied to a fuse link such that the fuse link is blown through an EM (electromigration) effect and Joule heating
Data Source
AI summary
A fuse circuit includes an electric fuse coupled to a first voltage source; a low resistance unit coupled to the electric fuse and having a junction which is capable of breaking down; and a switching unit coupled between the low resistance unit and a second voltage source.