A new concept for the use of Al‐sheet as integrated substrate for one or multichip module package

In this paper we present recent studies on the electrochemical migration processes in Ag thin film parallel microstrip lines in MCM(D) structures. The basic concept is applying accelerated local drop‐test of water solutions onto the surface of two adjacent lines, under a given voltage potential. These operational conditions are often met in the interconnection line buses, placed in the top assembly level of multilayered hybrid structures. The subject of investigations are MCM(D) developed on Al‐sheet carrier with internal conducting and isolating layers, produced through unique selective electrochemical anodization of Al and Ta. This technology process also enables the creation of embedded R and C passive components on the base of TaO_xN_1‐x and Ta₂O₅ (or Al₂O₃) respectively. We propose an electrochemical deposition of Ag/Sb alloys on the surface of Al interconnection lines and contact pads to ease the bondability and solderability in chip mounting procedures. The artificially created silver migrated defects and partial shorts are investigated through the high frequency method of coupled transmission lines in order to eliminate the errors and insufficient validity of DC direct measurements.