Research
Technologies and Standards to Realize Smart Manufacturing
SIR Test Method for Developing Evidence for the Production Assembly
Attributes of Cored Solder Wire in LED Luminaire Soldering
Selective Removal of Conformal Coatings by Pulsed Ultraviolet Lasers
Effect of Assembly Pitch and Distance on Solder Joint Thermal Cycling Life
Hybrid Conformal Coatings for Mitigating Tin Whiskers
Printing and Assembly Challenges for QFN Devices
Pad Cratering Susceptibility Testing with Acoustic Emission
MORE RESEARCH
Latest Industry News
Will iPhone 13 Trigger Headaches and Nausea?
You'll hear a lot about how boring the iPhone 13 is, but Apple is still poised to continue its sales super cycle
Foxtron, Taiwan's First EV, Leaks After Arriving in the Country: How Come?
NI, Elektro-Automatik Join Forces for EV Battery Testing
China's manufacturing growth slows
To Manage Your Time Better, Think Of It Like A Balloon
Out of the Verification Crisis: Improving RTL Quality
Deep Learning Method Produces Holograms Instantly
MORE INDUSTRY NEWS

Hybrid Conformal Coatings for Mitigating Tin Whiskers



Hybrid Conformal Coatings for Mitigating Tin Whiskers
In this stydy, nanoparticles were functionalized to bind them to the polymer structure while avoiding the collection among the particles.
Materials Tech

DOWNLOAD

Authored By:


Junghyun Cho, Suraj Maganty
Binghamton University (SUNY), Binghamton, NY, USA

Stephan J. Meschter
BAE Systems, Endicott, NY, USA

Dale Starkey, Mario Gomez, David G. Edwards
Henkel Electronic Materials LLC, Irvine, CA, USA

Abdullah Ekin, Kevin Elsken
Bayer MaterialScience LLC, Pittsburgh, PA, USA

Jason Keeping, Polina Snugovsky, Jeff Kennedy
Celestica Inc., Toronto, ON, Canada

Summary


A conformal coating of polyurethane (PU) consisting of hard and soft segments is being studied in an effort to prevent tin whisker penetration. For this, the coating needs to possess optimum mechanical properties by providing sufficient strength, modulus, and hardness while maintaining good ductility and toughness.

Typical monolithic PU films, however, do not possess all these required properties, so silica nanoparticles are incorporated into a PU film to improve its whisker mitigation effectiveness. In the present work, nanoparticles were functionalized to bind them to the polymer structure while avoiding the agglomeration among the particles.

Selection of the ideal concentration of nanoparticles is determined by establishing microstructure-property relations. Structural features at different length scales are characterized by various instruments including atomic force microscope (AFM) and scanning electron microscope (SEM) while mechanical properties are evaluated via macroscopic tensile testing as well as nanoindentation.

In particular, the nanoindentation testing emulates the whisker penetration behavior by producing local deformation of PU around an indenter tip.

Conclusions


Functionalized nanosilica particles approximately 20 nm in diameter were added to a PU coating in an attempt to attain its optimum mechanical properties for mitigating tin whisker growth. It was shown that mechanical properties do not continuously increase with the nanosilica concentration.

This was due to non-uniform distribution of nanosilica and polymer structure change with added nanoparticles. Phase separation also seemed to be affected by the presence of nanosilica. In particular, microdefects created during film processing are responsible for film brittleness and limited ductility.

Establishment of the structure - property relationship is essential to identify optimal microstructures of the nanoparticle-filled PU, which can be of importance in tin whisker mitigation.

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
01005 Component Challenges and Bugs
Insulation Between Overhanging Component Lead and Circuit Conductor
Sticky Residue Under Low Clearance Parts
Finding the Cause of Cold Solder Joints
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
Options for Reballing BGA Components
Solder Paste Viscosity
MSD Components Baked Too Long
Aluminum Trays and Rapid Static Discharge
Seeking IPC and J-STD Definitions
Is Component Lead Damage Reparable?
BGA Solder Ball Shelf Life
Conformal Coating Press Fit Connectors
MORE ASK THE EXPERTS