Laser Direct Structuring of Millable BN-AlN Ceramic for Three-Dimensional (3D) Components

Abstract

This research introduces a novel process for the direct metallization of the composite ceramic BN-AlN, a millable, high-temperature resistant material, using laser direct structuring (LDS). LDS is, for example, used for molded interconnect devices (MIDs), to integrate mechanical and electronic functions into a single 3D structure. Traditionally, MIDs have relied on polymers, but increasing thermal demands in electronics are shifting focus toward ceramic substrates like BN-AlN, which offer superior thermal stability and mechanical strength. Herein, electronic infrastructures are applied onto milled BN-AlN 3D components through a parameter study on laser activation and electroless copper deposition, followed by the development of a sequential copper–nickel–gold (CuNiAu) deposition process. The laser structuring reveals small grains of elemental aluminum on the surface, which directly catalyzes metal reduction in the electroless copper deposition. The duration and temperature of the copper electroplating process are found to influence the nuclei size and layer thickness. A palladium chloride treatment, as well as additional etching steps during the CuNiAu layer deposition, shows promising results. The metallized BN-AlN substrates are characterized for adhesion, contact reliability, resistivity, and thermal stability. The findings demonstrate the process's suitability for high-temperature applications, highlighting its potential for advancing electronic system integration.