A heating assembly for heating semiconductor substrates includes a plurality of heating devices, with each heating device including an energy emitting filament adapted for electrically coupling to an external power supply and housed in a first enclosure. The first enclosure comprises energy transmitting material so that energy generated by the filament will be transmitted through the enclosure. A second enclosure houses the first enclosure, which also comprises energy transmitting material. The second enclosure is coated with a reflective layer and is housed in a third enclosure of transmitting material, which encapsulates the reflective coating so that when the energy emitting filament is energized, the reflective coating is contained in the heating device. A heating assembly includes a frame having a plurality of supports for supporting a plurality of the heating devices. The heating devices are arranged in at least two heating zones, a first of the heating zones for heating a peripheral region of the semiconductor substrate and a second of the heating zones heating central regions of the semiconductor substrate. A first group of heating devices forming the first heating zone are spaced a first distance from the substrate. A second group of heating devices forming the second heating zone are spaced a second distance from the substrate wherein the first distance is less than the second distance so that more energy is directed to the peripheral regions of the substrate that the central regions.