Laser-driven shocks to explore the effects of aging on the adhesion of silver sintered on copper substrate

Abstract

The adhesion of thin silver joints sintered on metallic substrates is a major issue for their potential use in power electronics modules. Here, we explore how laser shock-induced spallation can provide a way to study this adhesion. Due to wave interactions inside the shock-loaded assembly, dynamic tensile stresses are induced near the copper-silver interface, resulting in partial or full removal of the silver layer. In order to investigate the effects of aging on the interface strength, experiments are performed on both as-sintered and aged samples. Time-resolved measurements of the free surface velocity provide information on wave dynamics and interface failure, but finite-element simulations show that inferring a quantitative value of the bonding strength from these data is still challenging. Nevertheless, post-recovery observations provide original insight into the debonding process, including some complex effects of aging, consistent with trends reported in the literature.

Keywords:

• Interface strength
• laser shocks
• sintered silver
• spallation

Acknowledgments

We thank Amélie Caradec, Florence Hamon and Dr. Dominique Eyidi (Institut Pprime, UPR 3346 CNRS) for their kind support in microscopy, as well as Anna Gordun and Kokouvi Happy N’Tsouaglo for helpful assistance in sample preparation.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was partially funded by the French Government programs ‘Investissements d’Avenir’ LABEX INTERACTIFS [reference ANR-11-LABX-0017-01].