ATE Input Capacitance Measurement via Stray Capacitance Subtraction
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Solution Overview
Problem
Automated test equipment (ATE) faces challenges in accurately measuring the input capacitance of Device Under Test (DUT) pins due to stray capacitance from the ATE circuitry, which is typically larger than the input capacitance of the pin, making it difficult to characterize input pins without dedicated equipment.
Innovation Solution
A method and apparatus using Pin Electronics (PE) to measure input capacitance by taking capacitance measurements with and without the DUT connected, calculating the input capacitance by subtracting the disconnected measurement from the connected measurement, and utilizing existing AC and DC testing circuitry without adding dedicated capacitance measurement hardware.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If ATE uses existing Pin Electronics for measurement, then device complexity is reduced, but measurement precision deteriorates due to stray capacitance from ATE circuitry
Solution Approach 1:
The patent extracts the harmful stray capacitance effect by measuring and separating it from the total capacitance. It measures the capacitance of the Pin Electronics alone (without DUT) and subtracts this value from the total capacitance measurement (with DUT), thereby extracting only the DUT's input capacitance and eliminating the influence of ATE circuitry's stray capacitance.
Solution Approach 2:
The patent introduces an intermediary measurement approach by using the Pin Electronics as a mediator to measure its own capacitance separately. This intermediary measurement allows the system to account for and compensate the stray capacitance effect, enabling accurate measurement of the DUT's input capacitance through subtraction.
2Device complexity
If ATE measures capacitance without dedicated equipment, then device complexity is reduced, but measurement precision worsens due to stray capacitance interference
Solution Approach 1:
The patent makes the Pin Electronics multi-functional by using it both for its original purpose of testing DUT electrical characteristics and for measuring its own capacitance. This universal approach eliminates the need for dedicated capacitance measurement equipment while maintaining measurement accuracy through the subtraction method.
Solution Approach 2:
The Pin Electronics performs self-measurement of its capacitance using the same testing infrastructure. By measuring its own capacitance value and using this information to compensate for stray capacitance effects, the system achieves accurate DUT capacitance measurement without requiring external dedicated measurement devices.
3Device complexity
If ATE characterizes input pins without dedicated capacitance measurement hardware, then device complexity is reduced, but measurement precision deteriorates due to stray capacitance
Solution Approach 1:
The patent performs preliminary measurement of the Pin Electronics capacitance before measuring the DUT. This preliminary action allows the system to pre-determine the stray capacitance value and use it to compensate for measurement errors, ensuring accurate characterization of the DUT's input capacitance even without dedicated measurement hardware.
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 and efficient measurement of input capacitance of DUT pins using existing ATE resources, allowing for characterization without additional circuitry and improving the ability to test and characterize integrated circuits.
Implementation Method 1
driving the PE with one or more predefined currents using a current source, and measuring one or more respective voltages that form across the PE responsively to the currents
Implementation Method 2
obtaining a first capacitance measurement while the pin is disconnected from the PE, and a second capacitance measurement while the pin is connected to the PE
Data Source
AI summary
A method for measuring an input capacitance of a pin of an electronic device includes, using a tester including Pin Electronics (PE), obtaining a first capacitance measurement while the pin is disconnected from the PE, and a second capacitance measurement while the pin is connected to the PE. The input capacitance of the pin is calculated from the first and second capacitance measurements.