Morphologies of Reactive Nanolayer Stacks Sputtered on Ceramic Low‐Temperature Cofired Ceramic Substrates Having a Micrometer‐Scale Surface Roughness

Abstract

The deposition of reactive multilayer systems (RMSs) is investigated on low-temperature cofired ceramic (LTCC) substrates having different surface morphologies. In this study, the morphologies of RMS layers that are deposited on glass-ceramic LTCC substrates are analyzed. Different surface morphologies are prepared through pretreatments of the LTCC surface. The considered surfaces encompass an untreated natural LTCC surface, a modified sintered LTCC surface by laser ablation, a surface with a deposited metallization layer, and finally, a surface with an additional solder layer put on the deposited metallization layer. The different pretreatments lead to significant differences in the roughness of the LTCC substrates, resulting in different reaction velocities and peak temperatures on the various surface morphologies after the RMS’s reaction. As a result, different grades of structural integrity (liftoff, crack formation) between the reacted RMS layer and the LTCC are observed.