Efeito da adição de grafeno nas propriedades interfaciais e mecânicas da solda SAC sobre cobre revestido com grafeno CVD

Abstract

The miniaturization of electronic components and the increasing density of interconnections require highly reliable solder joints, in which controlling the growth of intermetallic compounds (IMCs) is essential for mechanical and electrical stability. This study investigates the influence of graphene in two preparation methods—nanoparticles obtained by liquid-phase exfoliation (LPE) and thin films grown by chemical vapor deposition (CVD)—on the interfacial behavior of the lead-free SAC (Sn–Ag–Cu) solder alloy applied to copper substrates. SAC composites containing 0.05% and 0.5% by mass of graphene were prepared and subjected to a controlled reflow process. In parallel, CVD-grown single-layer graphene was deposited onto copper foils in a CH₄/H₂ atmosphere at 1000 °C for 60 minutes, acting as a diffusion barrier. The interfacial microstructure was analyzed by optical microscopy, evaluating the formation of intermetallic compounds (IMCs) (Cu₆Sn₅ and Ag₃Sn), while nanoindentation tests provided Vickers microhardness data, as well as the elastic modulus and plastic deformation of the brazed joints. The results indicate that the presence of graphene reduces the thickness of the intermetallic layers, improves interface uniformity, and enhances the mechanical performance of the joint by restricting Cu diffusion and promoting heterogeneous nucleation during solidification.The results indicate that graphene, acting both as a dispersed reinforcement and as a CVD interfacial film, represents a promising nanostructure for enhancing the reliability, thermal stability, and electrical integrity of SAC welds in advanced electronic applications.