Scaling of semiconductor devices over past decades has been made possible by continuous innovations in materials engineering as well as device integration and geometries. Thermal processing has been an enabler for manufacturing advanced devices, both as a unit process and in concert with other key technologies like ion implantation, epitaxy, and film deposition. This paper reviews the evolution of annealing technology with a special consideration to thermodynamics, kinetics and integration thermal budgets. Equipment and process innovations to meet ever-changing material and device fabrication requirements are presented.