Work

A Comprehensive Methodological Approach Towards the Micromechanical Characterization of Lead-Free Solder Joints

Year: 2025

Type: article

Abstract: In light of continued trends regarding increased complexity and ongoing miniaturization in microelectronics, advanced characterization approaches for miniaturized components are essential. We present a comprehensive experimental approach combining multiple small-scale mechanical testing techniques to characterize plastic deformation mechanisms in lead-free SAC305 soft solder. The Sn-rich matrix features a highly anisotropic β-Sn body-centered tetragonal crystal structure, resulting in a complex deformation behavior. Our approach integrates advanced nanoindentation methods with in situ microcompression testing to bridge length-scales and deformation regimes. Through nanoindentation, we quantified rate-dependent plasticity, revealing a particularly high stress exponent (n = 15.52), indicating that deformation is strongly hindered by obstacles. The activation volume of ~ 25 b3 corresponds to bcc materials, signifying that deformation is likely controlled by a dislocation-based kinking mechanism. In situ microcompression experiments enabled observation of slip-system activation, documenting the operation of (100)[010] slip-systems with a Schmid factor of m = 0.44 at a critical resolved shear stress of ~ 30 MPa. This favorably aligns with stress–strain curves from spherical nanoindentation. Important experimental details to effectively integrate multiple testing methods are highlighted, facilitating comprehensive scale-bridging understanding of mechanical behavior in solder materials. The presented framework is generally applicable to evaluate mechanical properties and deformation mechanisms in systems where traditional bulk testing is not feasible.

Source: JOM

DOI: 10.1007/s11837-025-07289-z

Authors: Nadine Buchebner, Julius F. Keckes, Verena Maier-Kiener, Peter-Julian Imrich, Daniel Kiener

Institution: Montanuniversität Leoben

Language: English

Topic: Electronic Packaging and Soldering Technologies

Subfield: Electrical and Electronic Engineering

Field: Engineering

Domain: Physical Sciences

Open Access status: hybrid

Estimated APC paid: $3,790

Funder: Österreichische Forschungsförderungsgesellschaft