In a system for thermal processing of a semiconductor substrate, an RTP
system employs a reflector plate which is highly reflective of radiation
in a target wavelength range, and less reflective of radiation outside
that target wavelength range. In one embodiment, the reflector plate has a
highly reflective portion overlying a less reflective portion, wherein the
highly reflective portion is highly reflective of radiation in the target
wavelength range. As radiation emitted by the substrate is received on the
reflector, the radiation in the target wavelength range is reflected,
thereby facilitating measurement of the substrate temperature by the
pyrometer(s), while radiation outside the target wavelength range is
absorbed, thereby facilitating cooling of the substrate.
