In this study, the impact of various annealing schemes on the formation and agglomeration mechanisms of ultrathin Ni(Pt)Si films is investigated. To this end, 11 ± 1 nm-thick Ni(Pt)Si films are grown on 300 mm Si(100) wafers using various traditional rapid thermal annealing procedures as well as laser annealing. The obtained silicide films are then subjected to additional annealing between 500 and 800 °C, to evaluate their stability at high temperature. The correlation between the as-grown Ni(Pt)Si film properties and their capability to withstand agglomeration is analyzed via a complementary approach of several techniques (Rs, ellipsometry, TEM-EDX, SEM, and EBSD). Texture comparison for ultrathin films give deeper insights into the role of the NiSi-(010) and NiSi-(013) orientations in the agglomeration phenomenon. Depending on the annealing schemes used during the silicide formation, there is a strong correlation between the initial microstructure of Ni(Pt)Si films and their subsequent degradation. Indeed, cross-analysis of these different key parameters indicates that the presence of small Ni(Pt)Si grains (40 nm) obtained after laser annealing, and a high ratio of Ni(Pt)Si grains oriented along the (013) direction appears to be more efficient in delaying the agglomeration to higher temperatures.