Influences of low dose gamma radiation on hardness and microstructure properties of green solder joint

Abstract

Microelectronic packaging is frequently used in almost every application involving radiation-related industry. In the present work, the effect of the low dose gamma radiation on hardness and microstructural properties of Sn3Ag0.5Cu solder was explored using triboindenter test and optical microscope. The solder paste was placed onto the printed circuit board utilizing stencil printing method and reflow soldering process. The solder samples were exposed to the gamma irradiation with various low doses (from 5 to 25 Gy). Prior to indentation test, the sample undergoes the standard metallographic procedure. The hardness properties were determined through indentation test while the microstructureof the sample was observed using an optical microscope. In this study, indentation technique was used to understand the evolution of hardness properties of solder sample subjected to gamma radiation. The results show that the hardness increased after exposure to gamma radiation. However, the hardness decreased as the increment of radiation dose. Exposure to the gamma irradiation resulted the microstructure instability of solder joint which increases the intermetallic compound layer and reductionin the properties of hardness.