TIVA Failure Site Detection Using AC Coupling
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Solution Overview
Problem
The Thermal Induced Voltage Alteration (TIVA) tool is limited in identifying and mapping failure sites with small AC signal fluctuations superimposed on a large DC level, restricting its application to only a limited set of error conditions.
Innovation Solution
The method involves connecting a TIVA to the output of a Device Under Test (DUT), using an AC coupling circuit with a capacitor to isolate the DC component, and a constant voltage or current source with a resistor to monitor and identify anomalies, allowing the TIVA to detect and map small AC signal variations by superimposing an AC component onto the DC signal.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If TIVA monitors DC power supply variations to identify leakage current sites, then leakage current error sites can be detected, but small AC signal fluctuations superimposed on large DC level cannot be identified
Solution Approach 1:
The patent segments the signal monitoring function by separating AC and DC components. It connects the TIVA to both the power supply and output of the DUT, using AC coupling circuits (capacitors) to extract only the AC signal component from the output, while simultaneously monitoring DC variations at the power supply. This segmentation allows independent detection of both AC signal anomalies and DC leakage currents.
Solution Approach 2:
The patent introduces AC coupling capacitors as intermediary elements between the DUT output and the TIVA measurement system. These capacitors block the large DC component while allowing the small AC signal fluctuations to pass through to the TIVA, enabling detection of AC anomalies without being overwhelmed by the DC level.
2Reliability
If TIVA uses laser scanning to thermally induce voltage changes and monitor DC power supply, then leakage current sites are identified, but the system cannot detect small AC signal anomalies
Solution Approach 1:
The patent segments the measurement function into two parallel paths: one monitoring DC power supply variations for leakage current detection, and another path using AC coupling to extract and monitor only the AC signal component from the DUT output. This segmentation enables the TIVA to detect small AC signal anomalies that were previously buried in the large DC level.
Solution Approach 2:
The patent applies local quality by using AC coupling capacitors specifically at the output measurement points where AC signal detection is needed, while maintaining the original DC monitoring capability at the power supply. This localized modification enables AC detection without affecting the existing reliable DC leakage current detection functionality.
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 enables the TIVA to effectively identify and visually map failure sites on the DUT, overcoming its previous limitations by isolating the DC component and detecting small AC signal anomalies, thereby expanding its capability to identify a broader range of error conditions.
Implementation Method 1
The AC component may be achieved by providing an AC coupling circuit between the DUT and the CPS, wherein the AC coupling circuit may include a capacitor
Implementation Method 2
the TIVA uses a laser (Infra Red spectrum) to scan and thermally induce resistances changes
Implementation Method 3
By scanning back and forth with the laser over the DUT surface along a path, as indicated by reference numeral 100, the TIVA produces localized heating of the circuitry
Data Source
AI summary
In an analysis of a semiconductor device under test (DUT) using a Thermal Induced Voltage Alteration (TIVA) tool, the TIVA is connected to an output of the DUT and the DC component on the output is decoupled from the TIVA. The remaining AC component from the output is analyzed by the TIVA while scanning the DUT with a scanning laser to identify locations on the DUT that produce signal anomalies at the DUT output.