Metallization of High Purity Al2O3 Substrate with Autocatalytic NiP Thin Films for Au Interconnections in MCM packaging technology.
Keywords:Autocatalytic NiP thin films, Electrolytic Au Thin films, MCM, Morphological Properties, Electrical Properties
A Multichip Module (MCM) is a structure consisting of several ICs (typically bare chips) interconnected on a common supporting substrate and packaged as a single device. In this packaging technology, gold (Au) thin films are used as interconnection tracks terminated by wire bonding process to the chips. Thus, the good quality of theses Au films (for interconnects purpose) is essential. The present work proposes a metallization sequence of high purity (99.9%) and polished Al2O3 substrates, with an autocatalytic (electroless) NiP thin film follow by an electrolytic Au film in order to improve the MCM interconnections quality. The results show NiP and Au films with good adhesion, low roughness, good thickness distribution and optimal electrical properties, which allows us to establish a methodology that guarantees the reproducibility and quality of the Au interconnections in MCM devices.