Thermoreflectance Thermography for 3D Thermal Characterization
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Solution Overview
Problem
Current methods for thermal characterization of semiconductor devices are limited by their inability to provide comprehensive three-dimensional thermal analysis, especially at the submicron level, and often require invasive or two-dimensional measurements, which do not accurately capture the intricate thermal behavior of complex, stacked devices.
Innovation Solution
A system combining high-resolution surface temperature mapping with a computational engine to compute a three-dimensional temperature field of semiconductor devices, using variable light sources and CCD cameras or lasers to measure thermoreflectance changes, allowing for non-invasive, in situ thermal characterization with submicron spatial resolution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If non-contact methods are used to measure surface temperature, then physical access requirements are eliminated, but information on internal three-dimensional thermal behavior cannot be obtained
Solution Approach 1:
The patent transitions from two-dimensional surface temperature measurement to three-dimensional internal thermal characterization by combining experimental surface measurements with computational modeling. The system uses thermoreflectance thermography to capture 2D surface temperature distributions and then employs inverse heat conduction algorithms to reconstruct the 3D thermal fields inside the device, effectively adding the depth dimension to the measurement capability.
Solution Approach 2:
The patent introduces computational modeling as an intermediary between surface temperature measurements and internal thermal characterization. The computational engine acts as a mediator that takes experimental surface data and device geometric/material properties as inputs, then produces inferred internal temperature distributions, bridging the gap between accessible surface measurements and inaccessible internal thermal states.
2Measurement precision
If contact methods are used to measure temperature, then direct temperature measurement is possible, but the probe itself influences and disturbs the system being measured
Solution Approach 1:
The patent replaces mechanical contact measurement methods with non-contact optical measurement. Instead of using physical probes that mechanically interact with the device, the system uses thermoreflectance thermography with light sources and cameras to measure surface temperature remotely, eliminating the mechanical disturbance caused by probe insertion while maintaining measurement capability through optical detection of thermal radiation and reflectance changes.
3Loss of information
If computational approaches are used to model thermal behavior, then insight into internal thermal behavior can be obtained, but the results are limited by uncertainties in heat source modeling
Solution Approach 1:
The patent implements feedback through an iterative inverse heat conduction process. The computational model predicts temperature distributions based on assumed heat source characteristics, compares these predictions with actual measured surface temperatures, and then adjusts the heat source model parameters to minimize the difference between predicted and measured data. This feedback loop continues until convergence, refining the heat source model accuracy based on experimental validation.
Solution Approach 2:
The patent merges experimental measurement and computational modeling into a unified hybrid approach. Rather than relying solely on theoretical heat source models or standalone experimental measurements, the system combines both methodologies, using experimental surface temperature data to constrain and validate the computational model, thereby reducing uncertainties in heat source characterization through the synergistic integration of measurement and simulation.
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
Enables accurate and efficient three-dimensional thermal characterization of semiconductor devices, mitigating the limitations of existing methods by providing detailed thermal insights without energy impartation, thus improving performance and reliability.
Implementation Method 1
uses a variable light source to illuminate the surface of an active micro-device. A CCD camera system then takes a high resolution image of the reflected light and produces a measure of the change in thermoreflectance for a given input power across the surface of the device
Implementation Method 2
uses a laser light to measure the change in thermoreflectance for a given input power across the surface of an active micro-device. This change in reflectivity translates to a two-dimensional temperature distribution across the visible surface of the device
Data Source
AI summary
A system and method to fully characterize the thermal behavior of complex 3D submicron electronic devices. The system replaces and/or supplements laser-based surface temperature scanning with a CCD camera-based approach. A CCD camera records multiple points of light energy reflected from an integrated circuit to obtain a temperature measurement. The system is used to non-invasively measure with submicron resolution the 2D surface temperature field of an activated device. The measured 2D temperature field is used as input for an ultra-fast inverse computational solver. The system couples measured results and computations in a novel approach, making it possible to extract geometric and thermal features of a device, and to obtain critically needed temperature distributions over the entire 3D volume of that device, including regions that are physically or optically inaccessible. The obtained distributions reflect the real, and not merely theoretical, physical construction and thermal behavior of that device.