Fuse Latch Circuit Clamping Against Radiation Soft Errors
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Solution Overview
Problem
Fuse circuits in semiconductor devices are prone to soft errors due to ionizing radiation, leading to frequent data inversions and increased neutron soft error rates, which affect the reliability and functionality of semiconductor memory devices.
Innovation Solution
Incorporating a latch circuit with a clamp circuit and inverters to maintain a constant level of the fuse data signal, using a first and second inverter to stabilize the signal, and a clamp circuit to prevent data inversion caused by alpha particle collisions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional latch circuit is used in the fuse circuit, then the device complexity is reduced, but the reliability deteriorates due to soft errors from ionizing radiation
Solution Approach 1:
The latch circuit is divided into two separate inverters (first inverter and second inverter) with distinct functions. The first inverter generates the inverted fuse data signal while the second inverter restores the original signal. This segmentation allows each inverter to be optimized for its specific function and enables the clamp circuit to protect only the critical first inverter output, reducing overall complexity while improving reliability.
Solution Approach 2:
The clamp circuit acts as an intermediary protective element between the first inverter output and the rest of the circuit. It detects voltage changes caused by alpha particle collisions and actively clamps the voltage to prevent data inversion, serving as a mediator that isolates the critical latch node from radiation-induced errors without requiring complete circuit redundancy.
2Reliability
If redundancy cells are added to replace defective cells, then the reliability is improved, but the device complexity increases
Solution Approach 1:
The clamp circuit is activated in advance to maintain the fuse data signal at a stable voltage level before radiation events occur. By pre-establishing voltage clamping protection on the critical first inverter output, the circuit proactively prevents soft errors from occurring, eliminating the need for post-error detection and repair mechanisms that would increase complexity.
3Reliability
If the latch circuit is protected against alpha particle collisions, then the reliability is improved, but the ease of manufacture deteriorates due to additional circuit elements
Solution Approach 1:
Rather than protecting the entire latch circuit uniformly, the solution applies protection locally and selectively only to the critical first inverter output node where fuse data signals are generated. The clamp circuit is positioned specifically at this vulnerable point, providing targeted protection against alpha particle collisions while leaving the rest of the circuit unchanged, thus maintaining ease of manufacture.
Data Source
AI summary
According to an embodiment of the present disclosure, a fuse circuit includes an input circuit and a latch circuit. The input circuit transmits a fuse data signal to a first node and its inversion to a second node, controlled by a first control signal. The latch circuit, which includes a first inverter, a second inverter, and a clamp circuit, latches these signals. The first inverter outputs the inversion signal from the first node to the second node, while the second inverter outputs the original signal from the second node to the first node. The clamp circuit, connected between a power voltage node and the second node, maintains the signal at the first node at a stable level in response to the control signal and the voltage at the first node.