Investigation of Current-Induced Mass Transport in thin Metal Conducting Stripes

The parameters governing void and whisker growth in aluminum thin metal conductors have been well defined in the past several years. Studies have also been conducted to define these parameters in other metal systems such as composite molybdenum-gold stripes. Nearly all of these studies have examined the test vehicle before and after stressing but rarely during the stress period. This paper interprets the results obtained when thin metal conducting stripes of molybdenum-gold and aluminum were current stressed while being viewed at high magnifications through the scanning electron microscope. To facilitate this, photographs were taken at a rate of one per minute and then used to produce a motion picture. When viewed, this allows real time study of reactions which occurred over extended periods of time. The study of these motion pictures confirmed some of the existing theories of void formation but has also resulted in a reevaluation of the subsequent movement of the voids along the conductor. The overall result of the experiment has been a greatly enhanced understanding of mass transport in conducting stripes.