Coaxial Laser Thermomechanical Testing for Partial Debond Detection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for testing heterogeneously integrated microelectronic systems are inadequate in detecting partial debonds and subsurface features in metal bump bond interconnects, which are prone to thermomechanical failure, especially in high-reliability applications like commercial or governmental systems.
Innovation Solution
A thermomechanical heating response testing system using a dichroic mirror to combine beams from multiple lasers, a single objective for focusing, and a multichannel lock-in amplifier to simultaneously measure thermal and mechanical responses, allowing for non-destructive analysis of metal bump bond interconnects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current testing methods (electrical testing, visual screening, C-SAM) are used, then testing can be performed, but partial debonds and subsurface features cannot be detected
Solution Approach 1:
The patent combines thermal probe laser and mechanical probe laser beams into a single optical path that focuses on the same sample location. The dichroic mirror merges these beams while maintaining separate detection paths, enabling simultaneous thermal and mechanical probing to detect both temperature changes and mechanical displacement caused by partial debonds
Solution Approach 2:
The dichroic mirror acts as an intermediary optical element that separates and combines beams of different wavelengths. It allows the thermal probe laser and mechanical probe laser to share the same optical path while maintaining spectral separation for independent detection, enabling multi-parameter measurement without requiring separate testing apparatus
2Measurement precision
If destructive cross-sectioning is used to analyze failure modes, then detailed structural analysis is possible, but the sample is destroyed and cannot be reused
Solution Approach 1:
The patent replaces mechanical destructive analysis (cross-sectioning) with optical non-destructive probing. The thermal probe laser measures temperature changes and the mechanical probe laser measures displacement caused by partial debonds, providing detailed failure analysis without physically damaging the sample
Solution Approach 2:
The system creates optical copies of the sample's thermal and mechanical states through laser probing. By measuring temperature and displacement fields, the system obtains detailed information about bond quality and failure modes without creating physical copies or destroying the original sample
3Measurement precision
If multiple separate testing systems are used to measure thermal and mechanical properties, then comprehensive characterization is achieved, but device complexity and testing time increase
Solution Approach 1:
The patent merges thermal probing and mechanical probing into a single integrated system. The dichroic mirror combines the optical paths of the thermal probe laser and mechanical probe laser, allowing simultaneous measurement of both temperature and displacement responses to the same heating stimulus
Solution Approach 2:
The single optical detection system performs multiple functions by detecting both thermal effects (temperature changes) and mechanical effects (displacement) using the same optical path and sample positioning, eliminating the need for separate testing apparatus
4Temperature
If conventional heating and detection methods are used, then thermal testing is possible, but mechanical displacement response cannot be simultaneously measured
Solution Approach 1:
The patent merges thermal and mechanical detection capabilities into a single simultaneous measurement system. The thermal probe laser measures temperature changes while the mechanical probe laser measures displacement, and both signals are acquired concurrently during the same heating cycle
Solution Approach 2:
The system uses periodic heating at multiple frequencies to excite both thermal and mechanical responses. The periodic heating causes cyclic temperature changes and corresponding mechanical displacement, enabling simultaneous detection of both responses through frequency-domain 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
The system provides enhanced sensitivity to detect partial debonds and mechanical displacement, offering a new mode of failure analysis without destructive cross-sectioning, suitable for high-reliability applications.
Implementation Method 1
a heating laser having a first wavelength
Implementation Method 2
heating laser... focused... on a sample
Implementation Method 3
a thermal probe laser having a second wavelength... reflected from a sample
Implementation Method 4
thermal probe detector configured to receive a thermal probe sample beam of the thermal probe laser reflected from a sample
Implementation Method 5
a mechanical probe laser having a third wavelength... reflected from the sample
Implementation Method 6
mechanical probe detector configured to receive a mechanical probe sample beam of the mechanical probe laser reflected from the sample
Implementation Method 7
a dichroic mirror configured to combine beams from a plurality of lasers
Data Source
AI summary
A thermomechanical heating response testing system and methods of performing a thermomechanical test on a sample are presented. A thermomechanical heating response testing system comprises a dichroic mirror configured to combine beams from a plurality of lasers, an objective immediately following the dichroic mirror, the plurality of lasers, and a multichannel lock-in amplifier configured to receive input from a thermal probe detector configured to receive a thermal probe sample beam of the thermal probe laser reflected from a sample and a mechanical probe detector configured to receive a mechanical probe sample beam of the mechanical probe laser reflected from the sample. The objective is configured to focus the beams of the plurality of lasers in a coaxial configuration on a sample. The plurality of lasers comprises a heating laser having a first wavelength, a thermal probe laser having a second wavelength, and a mechanical probe laser having a third wavelength.