a rapid thermal processor for heat treating and cooling semiconductor material is an elongated process chamber having a base , side and top walls which enclose a heater plate assembly through which thin pins longitudinally move to carry workpieces vertically to and from the heater assembly . a cooling shutter is adapted in the chamber to shield the workpiece from the heater plate when the cooling process takes place . the chamber has gaseous ambient control means which regulates the type of atmosphere or vacuum in the chamber during heat processing of the workpiece .