Harnessing heterogeneous nucleation to control tin orientations in electronic interconnections

Area of Science:

• Materials Science
• Electronics Manufacturing
• Crystallography

Background:

• Current electronics manufacturing relies on precise control, yet tin nucleation in solder joints remains stochastic.
• Variable melt undercooling and crystal orientations lead to inconsistent resistance against electromigration and thermomechanical fatigue.
• This variability impacts the reliability and lifespan of electronic components.

Purpose of the Study:

• To identify effective nucleants for controlling tin nucleation in solder joints.
• To demonstrate a method for incorporating these nucleants to achieve deterministic tin crystal orientation.
• To enable the fabrication of single-crystal solder joints with tailored c-axis orientation for specific failure mode resistance.

Main Methods:

• Identification of a novel family of nucleants for tin.
• Utilized a unique droplet solidification technique to validate nucleant effectiveness.
• Developed an approach for integrating nucleants into solder joints to direct nucleation events.

Main Results:

• Successfully identified and validated a family of tin nucleants.
• Demonstrated the ability to control tin nucleation orientation using the developed method.
• Achieved deterministic tin nucleation, moving away from a stochastic process.

Conclusions:

• The developed nucleants and incorporation method enable deterministic control over tin nucleation in solder joints.
• This control allows for the creation of single-crystal solder joints with optimized c-axis orientation.
• Tailored crystal orientation significantly enhances resistance to critical failure modes, improving electronic device reliability.