Investigations on Magnetic Ni-SAC305 Solder Material System for Inductive Melt Applications
Authors: R Gopala Krishan, Xu Ke, S. Arun Kumar, Eng Soon Tok, G. Yaadhav Raaj, and G Srayes Company: National University of Singapore and Advanced Integrated Analytical Test Services (A-IATS) Date Published: 5/19/2015
ICSR (Soldering and Reliability)
Abstract: Low-frequency electromagnetic induction (EMI) methodology and ferromagnetic materials are intensively probed in recent years in microelectronic interconnect arena. The precision and rapid EMI-centric heat reflow process has vast potential to enable advancement in solder-substrate interface reliability and productivity. A systematic study on the nature, distribution and impact of Ni on SAC305 solder material system by high temperature furnace and low-temperature mechanical alloying (MA) has been investigated through well-known X-ray diffraction (XRD), Differential Scanning Calorimetry (DSC), Scanning Electron Microscope-Energy Dispersive X-Ray Spectroscopy (SEM-EDX) and Vibrating Sample Magnetometer (VSM) experimentation. Experimental data suggests that the Ni in elemental form is predominantly responsible for magnetic property whereas the high temperature furnace resulted in non-ferromagnetic Ni3Sn4 formation. High resolution microspectroscopy has confirmed the presence and micron sized Ni in MA based flakes. The industrycentric heat reflow through rapid thermal process ( RTP ) complimented the Ni-Sn phase formation coupled with decline in magnetic and thermal property. The role of Ni as irreversible inductive micro-heatseed in SAC305 solder is explored for EMI-centric reflow oven applicability. The derived inductive melt time of 8sec at 15KhZ for MACentric 25 wt% Ni in SAC305 solder is a notable and unique spec at this juncture in SAC305 solder Techlandscape.