Shear strength between Sn–3.0Ag–0.5Cu solders and Cu substrate after two solid-state aging processes for fan-out package process applications

Microstructural and Mechanical Characterization of Cu/Sn Slid Bonding Utilizing Co as Contact Metallization Layer

“…The reasons of the detachment from inside the (Cu,Co) 6 Sn 5 were detailed in our previous work [35]. Furthermore, according to the results in the current study, the adhesion between Ti and IMCs is weak after the total consumption of the Co and Sn layers by IMCs formation(as seen for Sample A and The detachment of intermetallic compounds from interfaces between solder and the thin wetting layer used in under bump metallization (spalling phenomena) has been discussed in literature [63][64][65][66][67][68][69]. It has been shown that the spalling phenomena, when the large amount of solder remained, appears due to a high interfacial energy between IMCs and an adhesion layer (such as Cr and Ti) [63][64][65][66]68,69].…”