Fuse Cutting Test Circuit for Incomplete Break Detection
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Solution Overview
Problem
Conventional fuse cutting test methods in semiconductor storage devices face challenges in detecting incomplete fuse breaking, leading to unstable signal outputs and longer testing times, especially with high-speed SRAM products that require slow-rise fault detection.
Innovation Solution
A fuse cutting test method and circuit that measure the current flowing through the fuse to determine its state, using a current supply, comparison circuit, and determination circuit to output signals indicating whether the fuse is broken, unbroken, or incompletely cut, thereby distinguishing between switched and unswitched states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional fuse cutting test methods are used, then the testing process is simple, but incomplete fuse breaking cannot be detected leading to unstable signal outputs
Solution Approach 1:
The test circuit is segmented into distinct functional modules: a current supply unit that provides test current, a measurement unit that measures the voltage drop across the fuse, and a determination unit that compares the measured voltage against reference values. This segmentation allows each module to perform its specific function efficiently, improving measurement precision while keeping the overall system manageable through modular design.
Solution Approach 2:
The patent introduces a measurement unit as an intermediary between the fuse and the determination unit. This intermediary measures the voltage drop across the fuse and converts it into a comparable signal, enabling precise detection of incomplete fuse breaking without requiring direct complex interaction between the fuse and the control system.
2Reliability
If slow-rise fault detection is performed in high-speed SRAM products, then incomplete fuse breaking can be detected, but testing time increases
Solution Approach 1:
The patent replaces the mechanical/time-based slow-rise detection method with an electrical measurement approach. Instead of gradually raising power supply voltage over time to detect faults, the system applies test current and measures voltage drop instantaneously, achieving reliable fault detection without the time penalty of slow-rise testing.
Solution Approach 2:
The patent changes the detection parameter from time-based voltage rise rate to instantaneous voltage drop magnitude. By measuring the voltage drop across the fuse under test current and comparing it against reference values, the system can reliably detect incomplete fuse breaking in a single instant rather than requiring extended slow-rise testing periods.
3Productivity
If current measurement method is used, then rapid and precise fuse state detection is achieved, but additional circuit elements are introduced
Solution Approach 1:
The measurement unit serves multiple functions: it measures voltage drop across the fuse, converts the measurement into a comparable signal, and provides input to the determination unit. This multi-functionality reduces the need for separate dedicated components for each function, achieving rapid detection while minimizing the increase in circuit element quantity.
Solution Approach 2:
The patent merges the current supply, voltage measurement, and fault determination functions into an integrated test circuit system. The current supply unit, measurement unit, and determination unit work together as a unified system, allowing rapid fuse state detection while avoiding the complexity of separate independent circuits for each function.
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 rapid and precise detection of fuse states without lengthening testing times, providing stable results and minimizing interference from other elements, and can be applied to various semiconductor applications.
Implementation Method 1
When a fuse is not broken completely, the fuse functions as a high-resistance
Data Source
AI summary
A fuse cutting test method to test the state of a fuse includes measuring the current flowing through the fuse and determining the fuse to be either broken, or not broken, or in a state therebetween, based on the measured current.