Abstract

Heating apparatus particularly useful for rapid thermal processing of semiconductor wafers, includes: a head having a reflector and a support for supporting a wafer spaced above the reflector; a radiation heater located above the wafer, an optical fiber having one end exposed to the space between the wafer and the reflector for detecting the radiation emitted by the wafer as enhanced by the reflector; a heat measuring device at the opposite end of the optical fiber for producing a temperature measurement corresponding to the radiation emitted by the wafer as enhanced by the reflector; and a peripheral barrier circumscribing the head, reflector, and the wafer for blocking stray radiation from entering the space between the wafer and the reflector from the outer periphery of the head. The wafer support supports the wafer spaced from the peripheral barrier by an upper annular gap which includes an annular barrier projecting outwardly of the wafer towards the radiation heater to block all but low angle radiation from penetrating the annular gap.