System and method for thermal processing of a semiconductor substrate

Abstract

A semiconductor substrate processing system and method using a stable heating source with a large thermal mass relative to conventional lamp heated systems. The system dimensions and processing parameters are selected to provide a substantial heat flux to the wafer while minimizing heat loss to the surrounding environment (particularly from the edges of the heat source and wafer). The heat source provides a wafer temperature uniformity profile that has a low variance across temperature ranges at low pressures. A resistively heated block is substantially enclosed within an insulated vacuum cavity used to heat the wafer. Insulating walls comprising a reflective material, such as polished tungsten, encapsulated within an inert insulating material such as quartz, may be used to provide insulation. The isothermal nature of the processing region may be enhanced by using multiple layers of insulating walls, actively heated insulating walls or a conductive gas to enhance heat transfer to the semiconductor substrate. A semiconductor substrate may be heated and cooled in stages in the processing system to avoid slip. Proximity, conductive gases and cooling gases may be used to increase or decrease the level of heating in stages.