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Article
Sn Whisker Growth During Mechanical Loading and Unloading: Highlighting the Critical Role of Stress in Whisker Growth
Whisker formation in metallic coatings has been studied extensively over the past few decades. A wide consensus exists for stress as a driving force behind whisker growth. However, many of the details are not ...
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Article
Analysis of Pressure-Induced Whisker Nucleation and Growth in Thin Sn Films
A recent publication (Jagtap et al. Scr Mat 182:43, 2020) reported real-time observations of stress-driven whisker nucleation and growth in a thin film of Sn subjected to pressure on part of its surface. This ...
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Article
Studying the Effect of Grain Size on Whisker Nucleation and Growth Kinetics Using Thermal Strain
To understand how and why Sn whiskers nucleate, measurements were performed in which the thermal expansion mismatch was used to induce strain in the samples. The current work focuses on the effect of grain siz...
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Reference Work Entry In depth
Stress Measurement in Thin Films Using Wafer Curvature: Principles and Applications
Wafer curvature is a useful and sensitive technique for measuring stress in thin films. This work describes the basis for wafer curvature measurements and how they can be used to understand stress evolution. V...
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Article
Quantifying the Effect of Stress on Sn Whisker Nucleation Kinetics
Although Sn whiskers have been studied extensively, there is still a need to understand the driving forces behind whisker nucleation and growth. Many studies point to the role of stress, but confirming this re...
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Living Reference Work Entry In depth
Stress Measurement in Thin Films Using Wafer Curvature: Principles and Applications
Wafer curvature is a useful and sensitive technique for measuring stress in thin films. This work describes the basis for wafer curvature measurements and how they can be used to understand stress evolution. V...
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Article
Investigation of Tin (Sn) Film Using an Aerosol Jet Additive Manufacturing Deposition Process
The quality of a Sn film deposited by the aerosol process is compared against the quality of Sn films deposited with traditional electroplating. Using the aerosol additive deposition technique, a Sn film was d...
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Article
Quantifying the Rates of Sn Whisker Growth and Plastic Strain Relaxation Using Thermally-Induced Stress
Whiskers and hillocks that grow out of Sn-based coatings are a critical reliability issue in Pb-free electronics. Although their growth is widely regarded as a stress-relaxation mechanism, quantitative underst...
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Article
Measuring the Stress Dependence of Nucleation and Growth Processes in Sn Whisker Formation
Sn whiskers/hillocks are believed to form due to stress in the layers, but the dependence on the stress has been difficult to quantify. We therefore used the thermal expansion mismatch between Sn thin films an...
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Article
Stress evolution in Si during low-energy ion bombardment
Measurements of stress evolution during low-energy argon ion bombardment of Si have been made using a real-time wafer curvature technique. During irradiation, the stress reaches a steady-state compressive valu...
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Article
Improved spatial resolution and lower-dose pediatric CT imaging: a feasibility study to evaluate narrowing the X-ray photon energy spectrum
This feasibility study has shown that improved spatial resolution and reduced radiation dose can be achieved in pediatric CT by narrowing the X-ray photon energy spectrum. This is done by placing a hafnium fil...
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Article
In Situ Measurement of Stress and Whisker/Hillock Density During Thermal Cycling of Sn Layers
Compressive stress is believed to be the primary driving force that makes Sn whiskers/hillocks grow, but the mechanisms that create the stress (e.g., intermetallic compound growth) are difficult to control. As...
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Article
Altering the Mechanical Properties of Sn Films by Alloying with Bi: Mimicking the Effect of Pb to Suppress Whiskers
Stress is believed to be the main driving force for whisker formation in Sn coatings on Cu. This suggests that whiskering can be suppressed by enhancing stress relaxation in the Sn layer, which is believed to ...
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Article
Correlation Between Surface Morphology Evolution and Grain Structure: Whisker/Hillock Formation in Sn-Cu
Sn whisker and hillock formation is a reliability risk that has become increasingly important as the electronics industry has moved toward Pb-free manufacturing. To prevent them, we would like to understand wh...
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Article
Stress Relaxation in Sn-Based Films: Effects of Pb Alloying, Grain Size, and Microstructure
Stress is believed to provide the driving force for growth of Sn whiskers, so stress relaxation in the Sn layer plays a key role in their formation. To understand and enhance stress relaxation in Sn-based film...
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Article
Thick beryllium coatings by ion-assisted magnetron sputtering
Thick (>150 μm) beryllium coatings are studied as an ablator material of interest for fusion fuel capsules for the National Ignition Facility. DC magnetron sputtering is used because of the relative controllab...
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Article
Effect of layer properties on stress evolution, intermetallic volume, and density during tin whisker formation
Compressive stress due to intermetallic (IMC) growth appears to be the main driving force for whisker formation, but many of the underlying mechanisms relating the IMC to stress and whisker formation are not u...
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Article
Thick Beryllium Coatings by Magnetron Sputtering
Thick (>150 μm) beryllium coatings are studied as an ablator material of interest for fusion fuel capsules for the National Ignition Facility (NIF). As an added complication, the coatings are deposited on mm-s...
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Article
A Study of the Crystallization of Amorphous Indium (Tin) Oxide
The crystallization of amorphous indium oxide thin films with zero to 9.8 wt% SnO2, was studied using a combination of in situ MOSS (multibeam optical stress senor) and in situ resistivity measurements. We report...
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Article
Real-time SEM/FIB studies of whisker growth and surface modification
We report on real-time measurements that enable us to watch the morphology of whiskers and hillocks forming in real-time and provide insight into the mechanisms controlling their growth and initiation. These m...
