On the Issue of Thermal Stability of Metallization Systems and Contacts of Ultra-Large Integrated Circuits

The work is devoted to the development of a method for diagnosing thermal overloads of metallization systems of ultra-large integrated circuits. The considered metallization systems with a thickness of 0.5 μm with sublayers with a thickness of 0.1 μm (the width of the Al film was 7–70 μm) were exposed to single rectangular current pulses with a duration of no more than 600 μs and an amplitude of up to 8·1010 A/m2.Temperature fields were modeled using experimental oscillograms, melting processes in multilayer thin-film systems were analyzed. It was found that when exposed to a single rectangular current pulse with a duration not exceeding 80 μs and an energy of 85 mJ, the processes of melting of a metal film are the priority process of destruction of the structure. An increase in the pulse duration (τ>80 μs) changes the priority of thermal degradation, and contact melting becomes the main mechanism. It is shown that the presence of titanium and silicon oxide sublayers increases the thermal "load" on the metallization layers and can lead to a decrease in the critical current density. Using the example of the Al–Ti–Si system, it was revealed that isothermal annealing leads to an improvement in the heat-conducting properties of the system and an increase in critical current densities.