Engineering

Metallurgy

Materials science

Mineralogy

Image processing

Joint (building)

Thermal expansion

Computer science

Digital image analysis

Soldering

Physics

Finite element method

Digital image correlation

Correlation

Mathematics

Image (mathematics)

Solid-state physics

Ball grid array

Condensed matter physics

Artificial intelligence

Geometry

Composite material

Digital image

Structural engineering

Chemistry

Modulus

Computer vision

Journal of Electronic Materials

This paper presents the characterization of the mechanical properties of three lead-free solder alloys 95.5Sn-4.0Ag-0.5Cu (SAC405), 96.5Sn-3.0Ag-0.5Cu (SAC305), and 98.5Sn-1.0Ag-0.5Cu (SAC105) at the solder joint scale. Several actual ChipArray ® ball grid array (CABGA) packages were cross-sectioned, polished, and used as test vehicles. Compressive tests were performed using a nanocharacterization system over the temperature range of 25°C to 105°C. Images of the cross-sectioned solder joints were recorded by microscope during the tests. The recorded images were then processed by using a digital image correlation (DIC) program to calculate the displacement and strain fields on the solder joints. Finite-element method (FEM) modeling was used to extract the Poisson’s ratio, Young’s modulus, and coefficient of thermal expansion (CTE) of the solder alloys over the temperature range. The methodology developed in this paper enables characterization of the mechanical properties of the actual solder joints at low strain range with high accuracy.

Characterizing the Mechanical Properties of Actual SAC105, SAC305, and SAC405 Solder Joints by Digital Image Correlation