Research
Innovative Panel Plating for Heterogeneous Integration
A Method to Investigate PCB Supplier Rework Processes and Best Practices
The Effects of PCB Fabrication on High-Frequency Electrical Performance
Aerosol Jet Printing of Conductive Epoxy for 3D
EOS Exposure of Components in the Soldering Process
High Thermo-Mechanical Fatigue and Drop Shock Resistant Alloys
Filling of Microvias and Through Holes by Electrolytic Copper Plating
NASA DOD Phase 2: Copper Dissolution Testing
MORE RESEARCH
Latest Industry News
How Telecom is Rolling Out 5G During a Pandemic
Can Software Performance Engineering Save Us From the End of Moore's Law?
Tech stocks have been a winning bet, but investors worry it will fade
All This Chaos Might Be Giving You 'Crisis Fatigue'
Notebook PCB makers to see tight capacity through 3Q20
How Effective Is Nano Coating On Stencils?
U.S. Critical Infrastructure Full of Security Holes
Auto Interior Is the New Exterior
MORE INDUSTRY NEWS

Lead-Free Alloys with Ultra-High Thermo-Mechanical Reliability



Lead-Free Alloys with Ultra-High Thermo-Mechanical Reliability
Alpha focused on improving the properties of the bulk solder as well as controlled growth of interfacial IMCs and alloy microstructure.
Materials Tech

DOWNLOAD

Authored By:


Pritha Choudhury, Ph.D., Morgana Ribas, Ph.D., Ranjit Pandher, Ph.D., Anil Kumar, Sutapa Mukherjee, Siuli Sarkar, Ph.D., Bawa Singh, Ph.D.
Alpha, an Alent plc Company
South Plainfield, NJ, USA

Summary


Several new applications requiring solder materials that would perform for extended periods under harsh operating conditions have recently emerged. Clearly there is a need for a ROHS compliant solder with thermal and mechanical reliability better than Sn-Ag3-Cu0.5/ Sn-Ag4-Cu0.5 but with a similar melting range so that it can be a drop in replacement for these solders.

In the work shown here, Alpha focused on improving the mechanical properties of the bulk solder as well a controlled growth of interfacial IMCs and alloy microstructure. Major composition additions do impact the melting behavior and the bulk mechanical properties. Minor alloy additions can also alter the diffusion kinetics and have significant impact on the long term reliability. Tensile tests and high temperature creep tests were used for initial screening of the alloys and understanding the potential impact of each addition on the reliability of the solder in final application.

In this paper, a detailed study of the effect of small composition changes (major additions) and of micro additions is presented. Improvements in thermal, mechanical and metallurgical properties of the new alloys are discussed and compared to Sn-Ag3-Cu0.5. We show that the newly developed Pb-free solder alloy Maxrel Plus performs better than Sn-Ag3-Cu0.5 in high strain rate tests such as drop shock and vibration tests as well as in thermal fatigue tests.

Conclusions


A new Pb-free solder alloy has been developed which performs better than industry standard Pb-fee solder SAC305 in high strain rate tests such as drop shock and vibration tests as well as in thermal fatigue tests. A large number of alloys were designed, prepared and tested.

To screen the alloys, basic mechanical properties of the bulk alloy have been measured and used to predict its performance in the final real life application. Final selected candidate alloy, Maxrel Plus, has been extensively tested side by side with SAC305. Maxrel Plus performs better than SAC305 in drop shock, vibration and thermal cycling tests.

Initially Published in the SMTA Proceedings

Comments

No comments have been submitted to date.

Submit A Comment


Comments are reviewed prior to posting. You must include your full name to have your comments posted. We will not post your email address.

Your Name


Your Company
Your E-mail


Your Country
Your Comments



Board Talk
How Effective Is Nano Coating On Stencils?
What Causes Board Delamination?
01005 Component Challenges and Bugs
Sticky Residue Under Low Clearance Parts
Soldering Relays Intrusively in Lead Free Process
Printing vs. Dispensing
Maximum Board Temperature During Tin-Lead
Is There a Spacing Spec for SMD Components?
MORE BOARD TALK
Ask the Experts
Recommended Fiducial Shape
HASL vs. Immersion Gold
Very Low Temp PCBs
Looking for Long-term Component Storage Options
Baking After Cleaning Hand Placed Parts
Conformal Coating Recommendation
Burned Chip Repair
BGA Component Grounding Problem
MORE ASK THE EXPERTS