In recent years, much attention of developers of integrated microcircuits is given to designing novel types of microprocessors, development, and mastery of technologies of both multilayer 3D integrated circuits and making devices based on complex semiconductors. The aim of the present work is to study thermal processes in the Al-Ti-Si multilayer system up to the development of degradation processes. The degradation issues in aluminum metallization with titanium sublayer deposited onto silicon surface are considered. The evolution of processes of irreversible destruction of film conductor under passage through it of single square-wave current pulses with energy up to 300 mJ and duration of 50…1000 μs was analyzed. It was found that, under the action of a single square-wave current pulse with a duration of no more than 80 μs and energy of 85 mJ, the priority process of structural damage is the melting of the metal film. Increasing pulse duration (τ > 80 μs) changes the priority of thermal degradation, and contact melting becomes the main mechanism of structure damage. It was also found that isothermal annealing leads to improving system heat-conducting properties and increasing critical current densities. This is related to the improvement of adhesion properties of the structure as well as with phase transformations in the Al-Ti-Si system in the course of annealing. The results of the article can be used in further studies of the properties of the AI-TI-SI system, as well as in the creation of semiconductor structures taking into account properties such as high electrical conductivity, good processability, the absence of chemical components in the Al-Si system, chemical stability, and a tendency to electromigration, the possibility of short circuit, high diffusion mobility, low melting point, the inability to attach the wire by soldering.