Fuse Circuit Variable Resistor Sensing Verification
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Solution Overview
Problem
Existing fuse circuits in semiconductor memory devices lack reliability in programming and verification operations, leading to potential defects and inefficiencies in replacing defective memory cells with redundant ones.
Innovation Solution
A fuse circuit with a sensing unit featuring a variable resistor unit that adjusts resistance based on control signals, allowing for verification of program unit programming and detection of defective fuses, and a control unit that performs verification and re-programming operations across multiple modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fuse circuit is used to replace defective memory cells with redundant ones, then memory device functionality is restored, but reliability is reduced due to programming and verification defects
Solution Approach 1:
The sensing unit dynamically adjusts the resistance of the variable resistor based on control signals to optimize sensing sensitivity. The resistance value changes according to operation modes (program, verify, normal), allowing the circuit to adapt to different operational requirements and improve both reliability and sensing accuracy simultaneously
Solution Approach 2:
The patent changes the resistance parameter of the variable resistor in the sensing unit to optimize the sensing operation. By adjusting the resistance value through control signals, the sensing unit can accurately detect the programmed state of the program unit across different operation modes, resolving the contradiction between reliability and manufacturing precision
2Measurement precision
If a fixed resistance sensing unit is used, then circuit structure is simple, but sensing accuracy varies across different operation modes
Solution Approach 1:
The sensing unit employs a variable resistor whose resistance can be dynamically adjusted through control signals. This dynamic adjustment capability allows the sensing unit to maintain high sensing accuracy across program, verify, and normal operation modes without requiring multiple separate sensing circuits, thus balancing measurement precision with acceptable device complexity
Solution Approach 2:
The variable resistor in the sensing unit serves multiple functions across different operation modes. By adjusting its resistance value, the same sensing unit structure can accurately perform sensing operations during programming, verification, and normal operation, eliminating the need for mode-specific sensing circuits and reducing overall device complexity while maintaining universal sensing accuracy
Data Source
AI summary
A fuse circuit includes a program unit, a sensing unit and a control unit. The program unit is programmed in response to a program signal, and outputs a program output signal in response to a sensing enable signal. The sensing unit includes a variable resistor unit that has a resistance that varies based on a control signal, and generates a sensing output signal based on the resistance of the variable resistor unit and the program output signal. The control unit generates the control signal having a value changed depending on operation modes, and performs a verification operation with respect to the program unit based on the sensing output signal to generate a verification result. The program unit may be re-programmed based on the verification result.