• Sn-rich Pb-free solders are currently being utilized as replacement materials for Pb-rich solders in consumer microelectronics.
• During it’s service life an electronic device may experience mechanical shock, e.g., when a laptop computer is accidentally dropped from a small height.
• Our research focuses on quantifying the mechanical shock behavior of Pb-free solders.
• Understanding the mechanical shock behavior is crucial for designing microelectronic assemblies with superior reliability.
High Strain Rate Behavior of Environmentally-Benign Pb-free Solders
Nikhilesh Chawla, Arizona State University, DMR 0805144
Digital Image Correlation (DIC)
Load Frame
Phantom High Speed Camera
Video Imaging
Phantom Miro2 High Speed Camera (40 ms exposure per frame) 1 cm
Sn-3.9Ag-0.7Cu Tested at a Strain Rate of 10 s-1 (Local strain measurement, note
formation of double necking)
2
13
ε11
• The PI has actively recruited women and minorities to work on NSF-funded projects.
• Kyle Yazzie (shown in the picture on the right) is a Native American graduate student working on this project.
• Kyle got his Bachelor’s degree in Materials Science and Engineering from MIT
High Strain Rate Behavior of Environmentally-Benign Pb-free Solders Nikhilesh Chawla, Arizona State University, DMR 0805144
High Strain Rate Behavior of Environmentally-Benign Pb-free Solders Nikhilesh Chawla, Arizona State University, DMR 0805144
The integrated experimental and modeling efforts will provide a meaningful and quantitative understanding of dynamic behavior of Pb-free solders in electronic package and benefit the designers on developing reliable life prediction methodologies.
Finite element simulation of a double necking when a bar subject to dynamic tensile loading
Continuum modeling of interfacial strength between solder and copper based on embedded-atom potentialAdvantage of this approach: able to capture the nanoscale feature of the interface on the average sense
High Strain Rate Behavior of Environmentally-Benign Pb-free Solders Nikhilesh Chawla, Arizona State University, DMR 0805144
• Outreach to minority students:
The co-PI is working with Diné College from the Navajo Indian Reservation to invite Native American students to do research via ASU’s American Indian
Program (AIP) Summer Bridge Program .