Gradient Thermal Analysis for 3D Defect Localization
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Solution Overview
Problem
Traditional methods for diagnosing failures in electronic devices, particularly deep sub-micron technologies, face challenges in isolating internal defects due to small signal leakage paths and the complexity of stacked die structures, which are difficult to analyze using existing beam-based techniques.
Innovation Solution
The method employs gradient thermal analysis by inducing thermal gradients using energy sources like lasers to create precise thermal waves across the device-under-test, correlating time-of-flight data to determine the location of defects through trilateration, allowing for precise localization without damaging the device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If beam-based analysis techniques are used to diagnose failures in deep sub-micron technologies, then functional failures can be detected through parametric shifts, but the exact location of faults becomes difficult to isolate due to small signal leakage paths
Solution Approach 1:
The patent introduces thermal waves as an intermediary physical phenomenon to detect and locate defects. Instead of directly measuring electrical parametric shifts, the system uses laser-induced thermal waves that propagate through the device and interact with defects, making them detectable through secondary effects like light emission or structural changes.
Solution Approach 2:
The patent replaces traditional beam-based electrical analysis with optical/thermal analysis. Laser beams induce thermal effects that propagate through the device, and the resulting optical signals (light emission from heated regions) are detected, substituting electrical measurement with optical measurement for better spatial resolution.
2Reliability
If traditional beam-based techniques are applied to stacked die structures, then functional testing can be performed, but the analysis requires destruction or removal of one or more die to access embedded defects
Solution Approach 1:
The patent performs preliminary defect characterization using thermal waves before any destructive analysis. By inducing thermal waves and detecting their interaction with defects through optical signals, the system can identify and locate defects in stacked die structures while keeping the device intact, avoiding the need to remove or destroy die layers.
Solution Approach 2:
The patent changes the physical parameter used for defect detection from electrical properties to thermal-optical properties. By monitoring temperature-induced optical changes rather than electrical parametric shifts, the system can detect embedded defects in stacked die structures without requiring physical access or destruction of the device layers.
3Loss of information
If laser-induced thermal gradients are used to analyze embedded temperature sensitive defects, then functional anomalies can be identified, but the exact location remains inaccessible to direct laser analysis
Solution Approach 1:
The patent uses optical signals as an intermediary to detect thermal wave-defect interactions in embedded layers. The laser-induced thermal waves propagate through multiple die layers, and when they encounter defects, the resulting optical signals (such as light emission or refraction changes) provide information about the defect location without requiring direct laser access to the embedded region.
Solution Approach 2:
The patent transitions from direct one-dimensional laser scanning to three-dimensional thermal wave propagation analysis. By inducing thermal waves that propagate through the depth of stacked die structures and detecting optical signals from multiple angles and depths, the system can locate defects in three-dimensional space rather than being limited to surface-level analysis.
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 effectively isolates defects in electronic devices by creating controlled thermal gradients, enabling precise localization of faults in three dimensions without destroying the device, even in complex stacked die structures, thereby improving fault diagnosis efficiency.
Implementation Method 1
heating the test site at a controlled rate
Implementation Method 2
creating a precise thermal gradient across at least a portion of the device
Implementation Method 3
As the thermal gradient is propagated across the device, various measurements are correlated
Data Source
AI summary
A thermal gradient is induced in a device-under-test (DUT) and used to determine the location of a defect. In one embodiment, a laser creates a moving thermal gradient from a test site on the DUT and a respective time of flight for the thermal gradient to trigger a condition associated with the defect is determined. Repeating the time of flight testing at additional test site provides information used to trilaterate the defect in three dimensions. Alternately, a static thermal gradient is induced across at least a portion of the DUT along a first axis. The thermal gradient is incrementally walked along the first axis until the condition associated with the defect is triggered, thereby defining a first region. The thermal gradient is then induced along a second axis of the DUT and the process is repeated to define a second region. The location of the defect is determined to be the intersection of the first region with the second region.