ATE Calibration for Thermal EMF Error Correction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional automated test equipment (ATE) systems face challenges in accurately measuring low current and voltage due to thermal electromotive force (EMF) errors, as they do not account for variations in thermal EMF across different signal paths, leading to significant measurement inaccuracies.
Innovation Solution
The implementation of a calibration process that measures and characterizes thermal EMF for each individual signal path using a statistical method, allowing for the application of specific correction factors to improve measurement accuracy by offsetting measured values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional ATE systems perform DC voltage measurements, then measurement speed is maintained, but measurement precision deteriorates due to thermal EMF errors in signal paths
Solution Approach 1:
The patent applies preliminary action by performing calibration measurements before actual DC voltage measurements to characterize and store thermal EMF values for each signal path. The calibration process pre-determines correction factors that are then applied during normal measurements, eliminating the need for real-time thermal EMF compensation and maintaining measurement speed while improving accuracy
Solution Approach 2:
The patent introduces an intermediary calibration mechanism that measures and characterizes thermal EMF in each signal path separately. This calibration system acts as a mediator between the measurement system and thermal EMF errors, storing correction values that compensate for path-specific thermal effects without requiring complex real-time adjustments
2Measurement precision
If conventional ATE systems use single calibration value for all signal paths, then device complexity is reduced, but measurement precision deteriorates due to unaccounted thermal EMF variations
Solution Approach 1:
The patent applies segmentation by dividing the calibration process into individual signal path measurements. Each signal path is calibrated separately to determine its specific thermal EMF characteristics, allowing the system to account for variations in each path rather than using a single aggregate calibration value. This segmented approach improves measurement precision for low current applications
Solution Approach 2:
The patent implements local quality by assigning unique calibration values to each signal path based on its specific thermal EMF characteristics. Instead of applying a uniform calibration across all paths, the system tailors the calibration to local conditions of each signal path, improving measurement accuracy for paths with different thermal properties
3Reliability
If conventional ATE systems perform multiple tests on DUTs, then product quality assurance is improved, but measurement accuracy deteriorates due to cumulative thermal EMF errors
Solution Approach 1:
The patent applies preliminary action by establishing signal path calibration values before conducting multiple DUT tests. These pre-determined calibration values remain valid across multiple measurements, allowing the system to maintain high measurement accuracy throughout extended testing sequences without accumulating thermal EMF errors
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 enhances the accuracy of low current and voltage measurements by accounting for unique thermal EMF variations in each signal path, thereby reducing measurement errors and improving the precision of DC voltage measurements.
Implementation Method 1
One typical problem that commonly arises in ATE systems, especially ones that perform low current measurements, e.g., pico-amps, is the presence of thermal electromotive force (EMF). The presence of thermal EMF can adversely affect low resistance measurement accuracy.
Data Source
AI summary
A method of error correction in automated test equipment (ATE) is presented. The method comprises calibrating the ATE using a calibration board, wherein the calibration board comprises a reference voltage. The calibrating comprises: (a) measuring the reference voltage using a reference channel and each of a plurality of channels in the ATE; (b) recording a series of differential voltage measurement values obtained from the measuring in a calibration module; and (c) calculating a respective correction factor for each of the plurality of channels utilizing the series of differential voltage measurement values. The method further comprises obtaining a measured voltage value for a DUT connected to a first channel in the ATE, wherein the first channel is one of the plurality of channels. Finally, the method comprises correcting the measured voltage value using a respective correction factor for said first channel.