Electromigration degradation

Common concerns involving metal contacts include adhesion to the substrate, degradation due to corrosion, electromigration etc. and the tendency for some multilayered metallization schemes to undergo rapid interdiffusion. Surface analysis has been used to address a number of these problems. 

Several studies have shown that while migration of cathode metal atoms such as Mg is not significant, indium migration from the ITO is a very considerable problem.159 160 Indeed, Lee et al.159 have shown that In migration occurs mainly during operation of the devices, i.e., it is an electromigration process, and that its presence is correlated with performance degradation. 

Although several attempts have been made to improve the step coverage of sputtered aluminum, the results have not been optima because other properties (such as electromigration resistance) of the aluminum were degraded. Clearly in ULSI there is a need for a contact/via planarization method. 

Today, these theories of solutions and of electrolytic solutions are used in the analysis of the solvent development of exposed resists, lithographic mask degradation due to corrosion, electromigration of chromium ions, etc. 

Nogami et al. have demonstrated that degradation of electromigration (EM) lifetimes can occur when Co divots are present in the interconnect stmctures as illustrated in Figure 2.10. 

Hybrid devices 51% open circuit (caused by resistor/capadtor opens, internal bond pad corrosion and electromigration), 26% degraded/improper output (distorted or slow response time output), 17% short circuit (electrostatic discharge (ESD) overstress, fractures, shorting wire bonds), 6%... 

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