Word Line Abnormality Detection in Semiconductor Devices
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Solution Overview
Problem
Existing semiconductor device testing methods require reading and writing operations, making them time-consuming, especially for flash memory, and face challenges in circuit design precision and area overhead in monitoring word line abnormalities.
Innovation Solution
A semiconductor device with a word line driver that supplies selection and non-selection voltages, and detection circuits to identify abnormalities based on current flow, eliminating the need for reading and writing operations and reducing the complexity of circuit design and area overhead.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If reading and writing operations are used to test memory cell array, then word line and bit line can be indirectly checked, but test time becomes excessively long
Solution Approach 1:
The patent extracts the word line testing function from the memory cell array testing context. By using a transistor column with gates connected to word lines and monitoring drain currents directly, the invention separates the word line detection from the memory cell read/write operations, enabling independent and rapid word line testing without time-consuming memory access operations.
Solution Approach 2:
The patent introduces a transistor column as an intermediary component between the word lines and the detection circuit. This transistor column converts the word line voltage states into measurable current signals at the drain, serving as a mediator that translates word line status into detectable electrical signals without requiring memory cell operations.
2Loss of time
If simple test method without reading and writing is implemented, then test time is reduced, but circuit design precision and area overhead become challenging
Solution Approach 1:
The patent makes the transistor column serve multiple functions: it acts as both the switching element for word line selection and the sensing element for abnormality detection. The same transistor structure that drives the word line also provides the current path for detection, eliminating the need for separate dedicated test circuits and reducing overall device complexity.
Solution Approach 2:
The transistor column performs self-testing by using its own current flow characteristics to indicate word line abnormalities. When a word line is abnormal, the corresponding transistor drain current changes, providing self-diagnostic information without requiring external test signals or additional sensing circuits.
3Reliability
If reading and writing operations are performed for testing, then memory cell functionality can be verified, but flash memory writing and erasing operations take excessively long time
Solution Approach 1:
The patent extracts the testing function from the memory cell operation context. By monitoring transistor drain currents directly in response to word line selection, the invention verifies memory cell array functionality without performing actual read/write/erase operations on the memory cells themselves, thereby eliminating the time-consuming flash memory programming and erasing operations.
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 a simple and efficient method to detect word line abnormalities without reading and writing, reducing test time and area overhead, and simplifying the design of the testing circuit.
Implementation Method 1
a first detection circuit configured to detect a first current flowing into the word line driver through a wiring supplying the selection voltage
Data Source
AI summary
A semiconductor device includes: a plurality of word lines; a word line driver; a first detection circuit; and a control circuit. The plurality of word lines is connected to gates of a plurality of memory cell transistors, respectively. The word line driver supplies one of a selection voltage and a non-selection voltage to each of the plurality of word lines. The first detection circuit detects a first current flowing into the word line driver through a wiring supplying the selection voltage when the selection voltage is supplied to one of the plurality of word lines through the word line driver. The control circuit detects abnormality of the plurality of word lines and the word line driver based on the first current.