Multi-Objective Optimization of Mn-Doped Tio2 Content for Wettability, Printability and Intermetallic Layer of Sac305 Pb-Free Solder Paste on a Cu Substrate

Abstract

Effects of Mn-doped TiO2 nanoparticles on the wettability, printability and thickness of intermetallic layer of SAC30 on a Cu substrate were studied in this paper. Concentration of Mn-doped TiO2 nanoparticles was varied from 0.05 wt.% to 1wt.%. The wettability was evaluated in terms of contact angle of solder on the copper substrate and the printability was measured from the volume ratio of printed solder on the copper substrate to volume of stencil opening. The experimental results showed that 0.10wt.% Mn-doped TiO2 led to the lowest contact angle while the printability was decreased with the increase of the added nanoparticles and the thinnest intermetallic layer was found at 0.50wt.% Mn-doped TiO2 nanoparticles. Mn-doped TiO2 concentration was then optimized using a desirability function to find optimal values for the three responses. It was found that 0.07wt.% was the optimal concentration for the three metrics — wettability, printability and thickness of the intermetallic layer.