The physics and technology of a relatively new, short‐time, thermal processing technique, namely rapid isothermal processing (RIP), based on incoherent sources of light for the fabrication of semiconductor devices and circuits, are reviewed in this paper. Low‐cost, minimum overall thermal budget, low‐power consumption, and high throughput are some of the attractive features of RIP. The discussion of RIP, in the context of other thermal processes, history, operating principles, different types of RIP systems, various applications of RIP using single processing steps, and novel applications of RIP, includinginsituprocessing and multistep processing, is described in detail. Current trends are in the direction of RIP‐dominated silicon integrated circuit fabrication technology that can lead to the development of the most advanced three‐dimensional integrated circuits suitable for applications such as parallel processing and radiation hardening. RIP is not only a superior alternative to furnace processing, but it is also the only way to perform certain crucial steps in the processing of compound semiconductor devices such as high‐mobility transistors, resonant tunneling devices, and high‐efficiency solar cells. Development of more accurate temperature measurement techniques and theoretical studies of heat transfer and other fundamental processes are needed. Dedicated equipment designed for a specific task coupled withinsituprocessing capabilities will dominate the future direction of RIP.