Semiconductor Electrical Fuse Detection Circuit
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Solution Overview
Problem
Existing semiconductor devices with electrical fuses face issues in accurately determining the programmed state due to incomplete disconnection, leading to erroneous readings, especially in anti-fuses with varying conductive states.
Innovation Solution
A semiconductor device configuration that includes an electrical fuse connected to a detection node via a selective transistor, a precharge transistor, a bias transistor, and a detection circuit, which uses a two-step current supply method to accurately determine the programmed state by adjusting the bias current and potential of the detection node.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electrical fuse disconnection processing is performed to store defective addresses, then non-volatile storage is achieved, but insufficient disconnection causes erroneous determination of fuse state
Solution Approach 1:
The patent applies dynamics by making the bias current adjustable rather than fixed. The bias current supplied to the detection node is dynamically changed between a first bias current (higher magnitude) and a second bias current (lower magnitude) based on the detection results, allowing the system to adapt to different fuse states and resolve the contradiction between reliability and measurement precision.
Solution Approach 2:
The patent implements periodic action through multi-stage detection processes. The detection circuit performs repeated measurements with different bias current levels, and the control circuit iteratively adjusts the bias current based on previous detection results until a definitive fuse state is determined, transforming a single static measurement into a dynamic periodic process.
2Reliability
If anti-fuse programming is performed by insulation breakdown, then conductive state change is achieved, but varying conductive levels (high, low, failed) cause reading difficulties
Solution Approach 1:
The system dynamically adjusts the bias current magnitude based on detection results. When the detection node potential indicates an intermediate or ambiguous state, the control circuit switches between first and second bias current levels to further probe the fuse state, enabling reliable differentiation among high conducting level, low conducting level, and failed programming states.
Solution Approach 2:
The detection circuit provides feedback about the detection node potential to the control circuit, which then adjusts the bias current accordingly. This feedback mechanism allows the system to iteratively refine the measurement and accurately determine the anti-fuse programming state despite varying conductive levels, resolving the detection difficulty.
3Measurement precision
If a single bias current level is used for detection, then detection speed is maintained, but accurate determination of various conductive states is compromised
Solution Approach 1:
The system dynamically selects bias current levels based on detection needs. The control circuit switches between first bias current (faster initial detection) and second bias current (more precise final determination) depending on the intermediate detection results, optimizing both speed and accuracy rather than using a fixed current level throughout.
Solution Approach 2:
The detection process performs preliminary assessment with the first bias current to quickly identify obviously conductive or non-conductive fuses. For fuses requiring more precise determination, the system then applies the second bias current as a follow-up action, achieving fast initial sorting with accurate final determination.
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 accurate reading of electrical fuses and anti-fuses in various conductive states without erroneous determinations, ensuring reliable programming and non-volatile data storage by differentiating between high and low conducting levels.
Implementation Method 1
a bias transistor that passes a bias current to the detection node in a state where the selective transistor is in an ON state and the precharge transistor is in an OFF state
Implementation Method 2
The electrical fuse is set to be a non-conductive state by generating heat by passing an electric current into the electrical fuse so as to disconnect it
Data Source
AI summary
To provide an electrical fuse that is connected to a detection node via a selective transistor, a precharge transistor that precharges the detection node in a state where the selective transistor is off; a bias transistor that passes a bias current to the detection node in a state where the selective transistor is on and the precharge transistor is off, and a detection circuit that detects a potential of the detection node in a state where the bias current is flowing into the detection node, wherein the bias transistor reduces an amount of the bias current in a stepwise manner or a continuous manner.