Metallization, Material Selection, and Bonding of Interconnections for Novel LTCC and HTCC Power Modules

Ceramic baseplates are important elements in the power modules of electric drives. This paper presents low-temperature cofired ceramic (LTCC) and high-temperature cofired ceramic (HTCC) materials for the fabrication of three-dimensional power modules. The silver-based metallization and power module assembly are presented, together with aluminum-based power wire bonding and an industrial procedure to achieve high solderability and bondability. The results of the bond tests using different metallization materials, especially cost-effective ones, are presented, together with the assembly of the power modules. The best results were achieved with Ag metallization and 380 µm Al wire and with Ag-Pd metallization and 25 µm Al wire, both on an LTCC base. The paper concludes with a dual-pulse electrical test of the power modules, which proves the quality of metallization, the type of material selected, and the correctness of the wire bonding and assembly.