Crystal Structure of Cu-Sn-In Alloys Around the η-Phase Field Studied by Neutron Diffraction

Neutron diffraction study of stability and phase transitions in Cu-Sn-In alloys as alternative Pb-free solders

“…The samples discussed in this work correspond to samples labelled S4, S5 and S6 in Ref. [13], and its compositions are listed in Table 1. The three alloys were annealed at 300 • C for 3 weeks to promote homogenization, and the ingots were then rapidly quenched to 0 • C. Powders were obtained by manually grinding the ingots for 10 minutes in an agate mortar.…”

“…The present work focusses on the thermal stabilty and phase transitions of the less-studied ternary η-phase in Cu-rich Cu-Sn-In alloys. We have followed the crystal structure using in situ thermodiffraction experiments using neutrons, a technique that proved to have major advantages over X-ray diffraction for this kind of metallic systems [10,11,12,13]. Phase transitions have also been monitored by differential scanning calorimetry (DSC) measurements.…”

The effect of platinum contact metallization on Cu/Sn bonding

“…were occupied by 100%Cu and 100%Sn, and the excess Cu atoms would occupy the 2d site [53]. In the PtSn crystal structure, the Pt and Sn atoms occupied the 2a and 2c sites respectively [54].…”

Phase stability and thermal expansion behavior of Cu6Sn5 intermetallics doped with Zn, Au and In

“…It has been proposed that stabilizing the crystal structure of Cu 6 Sn 5 could improve the joint strength and reliability [17] although the effect of composition on the crystal structure and stability of Cu 6 Sn 5 is not fully understood. The elements Ni, Zn, Au and In, which all are common elements in lead-free soldering systems exhibiting marked solubility in Cu 6 Sn 5 [18,19,20] are of significant practical importance in soldering, since the properties of the Cu 6 Sn 5 layer influence the reliability of the solder joints [18,19,21]. As discovered by Nogita et al [11,17,22,23,24,25] using synchrotron PXRD, transmission electron microscopy (TEM) and differential scanning calorimetry (DSC), the hexagonal structure of Cu 6 Sn 5 in lead-free solder alloys and joints containing trace Ni additions is very stable down to room temperature.…”

“…However, as electronic devices usually experience thermal cycling or thermal shock during operation, the interfacial layers of solder joints, which are commonly dominated by Cu 6 Sn 5 intermetallics, require sufficient chemical and thermal stability [6,10,11,14,15,18,19,23,25,26,27,28,29,30,31]. Therefore the thermal expansion behavior of Cu 6 Sn 5 over the service temperature range is of great importance with respect to the integrity of solder joints.…”