Interfacial enhancement of Ag and Cu particles sintering using (111)-oriented nanotwinned Cu as substrate for die-attachment

The electroplated (111)-oriented nanotwinned-Cu (nt-Cu) film was utilized as substrate for Ag and Cu sinter joining to improve the weak interface connection between the metal paste and the substrate. It was found that both Cu and Ag sinter joints using (111)-oriented nt-Cu film exhibited a higher bonding strength than that using traditional random-oriented Cu film. Especially, the joints sintered with Cu paste on (111)-oriented nt-Cu film possessed a higher bonding strength of 53.7 MPa at the sintering condition of 300 °C, 0.4 MPa in N₂ atmosphere, compared to that on random-oriented Cu film with a value of 31.3 MPa. The results show that as metal substrate layer, the (111)-oriented nt-Cu film can improve the connection performance of Ag and Cu sinter joints, which could further promote their application in die-attachment technology for the next-generation power semiconductors.