Migratory Gold Resistive Shorts: Chemical Aspects of a Failure Mechanism

Abstract

Integrated-circuit devices using the Ti/W/Au metal system are subject to failure mechanisms based on electrolytic corrosion. The migratory gold resistive short (MGRS) failure mode is one example of this mechanism and results in the formation of filamentary or dendritic deposits of gold between adjacent stripes. on the IC chip. This reaction requires the presence of a sufficient amount of water, a bias voltage between adjacent stripes, and the activation of the cathodic (-) stripe. Gold ions are transported from anode to cathode through a film of moisture adsorbed on the surface of the chip; halide ions are probably involved in the transfer. Their presence is verified experimentally by x-ray photoelectron spectroscopy. Some of the chemical and electrostatic factors involved in the MGRS mechanism are discussed in this paper, including the questions of a threshold level of moisture and contamination.