Pressureless Sintered-Silver as Die Attachment for bonding Si and SiC Chips on Silver, Gold, Copper, and Nickel Metallization for Power Electronics Packaging: The Practice and Science

Low-temperature silver (Ag) sintering is emerging as a cutting-edge die-attach technology for power electronics packaging. However, the industry still has concerns about completely accepting this technology. One of the reasons is a lack of knowledge about the mechanism and process of sintered silver bonding on various metallization. Before, we reported a preliminary assessment of the die-shear strength and microstructures of Si dummy device attached on Ag, Au, and Cu metallization. This research will go deeper into the practice and science of attaching Si and SiC devices with sintered-Ag on substrates with up to seven most widely used metallizations, including electroplated Ag, Ni/Au, and Ni, electroless-plated Ni(P)/Ag, Ni(P)/Au, and Ni(P), and native Cu on DBC substrate. All sintered-Ag die-attach were pressureless in the air at temperatures ranging from 220 °C to 300 °C. The mechanical, electrical, and thermal parameters, as well as the microstructural analyses, were assessed. The purpose of this research is to gain a better understanding by: 1) discussing effects of devices and substrate metallizations on the mechanical, electrical, and thermal characteristics; 2) reviewing fundamental mechanisms of interfacial adhesion for sintered-Ag bonding, and 3) providing practical considerations for developing Si and SiC sintered-Ag die-attaching profiles on the widely used substrate metallization.