Defects due to metal silicide precipitation in microelectronic device manufacturing: The unlovely face of transition metal silicides

摘要

In microelectronics technology transition metals and their silicides play a prominent, but twofold role: On the one hand, selected metals like Ti, Co, Mo and W and/or their silicides are used, e.g., for interconnects and source/drain contacts, on the other hand, transition metals, in particular Fe, Ni and Cu, entering inadvertently into the silicon substrates during device manufacturing can give rise to severe device yield and reliability problems. By electrical failure analysis methods providing failure detection and localisation in combination with structural defect (transmission electron microscopy (TEM)) and local elemental analysis methods (energy dispersive X-ray analysis (EDX)) metal silicide precipitates have been identified as cause of the malfunction of mass production devices. The electrical activity of the defects created due to the precipitation of the metals as silicides during device manufacturing processes in device active zones is interpreted on the basis of recently published extensive experimental and theoretical studies conducted on the mechanisms of the electrical activity of Cu and Ni silicide precipitates. [References: 50]