Terahertz Impulse Signal for High-Precision Defect Isolation
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Solution Overview
Problem
Conventional methods for testing and isolating defects in complex electronic packages, such as multi-chip modules, face challenges due to the difficulty in non-destructively detecting defects in high-frequency signals within silicon and metal structures, particularly in long silicon bridge structures, as existing technologies like TDR and EOTPR struggle with resolution and signal decay.
Innovation Solution
The method involves generating an impulse test signal by taking the time derivative of a step function signal and adjusting its bandwidth to enhance defect localization, using a test probe to apply and sense the signal, and employing a defect detection circuit to analyze the conducted test signal for indications of defects, including comparison with reference signals to determine defect location and type.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional TDR or EOTPR methods are used to detect defects in silicon bridge structures, then defect detection capability is provided, but measurement precision deteriorates due to signal decay and lack of resolution in long silicon bridge structures
Solution Approach 1:
The patent transforms the test signal from a conventional step function to an impulse signal by taking the time derivative. This parameter change in signal waveform enables the signal to maintain integrity over long silicon bridge structures, overcoming signal decay issues and achieving precise defect localization within 30 μm accuracy.
Solution Approach 2:
The patent replaces conventional electrical TDR methods with an electro-optic based impulse signal generation system. By using optical-to-electrical conversion to generate ultra-wideband impulse signals, the system achieves better resolution and reduced signal decay compared to traditional electrical step-function-based TDR methods.
2Adaptability or versatility
If advanced packaging technologies are implemented to increase functionality in small products, then device complexity increases, but difficulty of detecting and measuring defects increases
Solution Approach 1:
The patent applies segmentation by dividing the complex electronic package into testable segments through impulse signal propagation. The impulse signal travels through different portions of the silicon bridge and interconnect structures, allowing defect detection in specific segments without requiring destructive analysis of the entire complex package.
Solution Approach 2:
By changing the signal parameters to use ultra-wideband impulse signals with picosecond pulse widths, the patent enables detection of defects in complex advanced packaging structures that cannot be detected using conventional lower-frequency test signals, thus maintaining adaptability to new packaging technologies.
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 allows for non-destructive defect isolation in complex electronic packages with improved resolution, enabling the identification of defects within 30 μm accuracy and reducing yield loss by effectively addressing the limitations of existing technologies.
Implementation Method 1
An optical signal is provided to an electro-optic probe where the optical signal is converted to an electrical signal which is applied to a device under test (DUT). A defect in the DUT reflects a signal that affects an electro-optic crystal at the electro-optic probe.
Data Source
AI summary
An apparatus comprises a signal generator circuit, a test probe, a signal sensor circuit, and a defect detection circuit. The signal generator circuit is configured to generate an impulse test signal having an impulse waveform and adjust a bandwidth of the impulse test signal. The test probe is electrically coupled to the signal generator circuit and configured to apply the impulse test signal to a device under test (DUT). The signal sensor circuit is configured to sense a conducted test signal produced by applying the impulse test signal to the DUT with the test probe. The defect detection circuit is configured to generate an indication of a defect in the DUT using the conducted test signal.