Semiconductor Leakage Current Test Circuit Using Time-Based Measurement
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Solution Overview
Problem
Conventional leakage current test circuits face reliability issues due to process variations affecting pin capacitance and require increased circuit area for internal delay times, making them inefficient for self-testing in semiconductor circuits.
Innovation Solution
A semiconductor circuit with a test control unit, driver, and sensing unit that generates activation signals to drive and compare the voltage level of a pad with a reference voltage, while a compensation unit adjusts capacitance to minimize circuit area and improve reliability, allowing for self-testing of pin leakage currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional leakage current test circuit is used, then the test can be performed, but the reliability of the test deteriorates due to process variation affecting pin capacitance
Solution Approach 1:
The patent changes the test parameter from voltage level to time duration. By measuring the time required for the pad voltage to change from a first level to a second level after floating, the test becomes insensitive to capacitance variations caused by process changes, thereby improving test reliability while maintaining adaptability
2Measurement precision
If an internal delay time circuit is added to measure voltage level variation, then the leakage current test can be performed, but the circuit area increases
Solution Approach 1:
The patent uses the pad's own capacitance and leakage current to perform the measurement. The pad voltage naturally changes over time due to leakage current after being floated, and this natural voltage transition is measured directly, eliminating the need for separate delay time generation circuits or external testing equipment
Solution Approach 2:
The patent replaces complex electrical measurement circuits with a simple time-based measurement approach. Instead of using voltage probes and delay circuits to measure leakage current, the system uses a voltage-to-time conversion where the pad voltage change over time directly indicates leakage current magnitude, significantly reducing circuit area
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
The solution minimizes circuit area, enhances test reliability, and enables efficient self-testing of leakage currents by compensating for capacitance variations and controlling floating times, thereby improving the overall performance of the leakage current test system.
Implementation Method 1
a driver configured to drive the pad to a predetermined level in response to activation of the driving activation signal
Implementation Method 2
a sensing unit configured to compare a voltage level of the pad with a reference voltage in response to activation of the sensing activation signal, and output a sensing signal
Data Source
AI summary
A semiconductor circuit includes a test control unit configured to generate a driving activation signal and a sensing activation signal in response to a command and an address; a pad; a driver configured to drive the pad to a predetermined level in response to activation of the driving activation signal; and a sensing unit configured to compare a voltage level of the pad with a reference voltage in response to activation of the sensing activation signal, and output a sensing signal.