A Review on Phase Field Modeling for Formation of η-Cu6Sn5 Intermetallic

Abstract

Formation of intermetallic compounds (IMCs) exhibits remarkable microstructural features and provides opportunities for microstructure control of microelectronic interconnects. Excessive formation of brittle IMCs at the Cu/Sn interface such as η-Cu6Sn5 can deteriorate the reliability and in turn lead to solder joint failure in the Pb-free Sn-based solder joints. Phase field method is a versatile tool for prediction of the mesoscopic structure evolution in solders, which does not require tracking interfaces. The relationships between the microstructures, reliability and wettability were widely investigated, and several formation and growth mechanisms were also proposed for η-Cu6Sn5. In this paper, the current research works are reviewed and the prospective of the application of phase field method in the formation of η-Cu6Sn5 are discussed. Combined phase field simulations hold great promise in modeling the formation kinetics of IMCs with complex microstructural and chemical interactions.

In Situ Study the Grooving Effect Induced by Ag Particles on Rapid Growth of Cu6Sn5 Grain at Sn-xAg/Cu Soldering Interface during the Heat Preservation Stage

“…According to formulas (4) and ( 5), the From the perspective of diffusion flux, Figure 10 is the schematic diagram of the effects of the Ag 3 Sn cluster on the flux of Cu of interfacial IMC growth at the heat preservation stage of Sn/Cu and Sn-3.5Ag/Cu soldering interfaces (blue represents Sn based solder, yellow represents intermetallic compound (Cu 6 Sn 5 ), and reddish brown represents polycrystalline Cu substrate). In the interface reaction process between Sn and Cu, grain boundary diffusion is more dominant than bulk diffusion [33]. The flux of Cu atoms entering Sn or Sn-3.5Ag solder through grain boundaries, J Cu , can be expressed using Formula (5) [28].…”