Temperature measurement in RTP: Past and future

RTP emerged as a mainstream technology during the last two decades in part by solving a difficult technical challenge, that of reliable temperature measurement using optical thermometry. Current thermal processing chambers are capable of controlling temperatures which change at hundreds of degrees celsius per second with repeatability of less than one degree with uniformity on the order of a degree. This is accomplished in a radiatively heated environment where the optical properties of the substrate may vary arbitrarily and contact with it is not acceptable or even feasible. This high degree of thermal stability has enabled the production of the current generation of integrated circuits. Processing requirements are pushing the limits of traditional lamp based technology, and new techniques for sub-second anneals are starting to emerge. With the development of the sub-second anneal, temperature heating and cooling rates may exceed millions of degrees per second, and temperature control may become the limiting factor as it was in the early days of the evolution of the industry.