Heat treatment susceptor and heat treatment apparatus

A heat treatment susceptor holding a substrate when the substrate is irradiated with a flash of light from flash lamps to perform a heat treatment on the substrate, the heat treatment susceptor comprising:

• a holding plate having a planar holding surface;
• and
• a plurality of substrate support bodies mounted upright on the holding surface, wherein
• at least one slit is formed around a position where at least one of the substrate support bodies is mounted upright in the holding plate, and
• the slit includes at least one bending portion or one corner portion surrounding at least one of the substrate support bodies,
• the plurality of substrate support bodies are mounted upright on a first circumference and a second circumference having a larger diameter than a diameter of the first circumference,
• the slit having a U-like shape or a V-like shape with an opening portion directed to the central portion of the holding plate is formed around a position where each of the substrate support bodies are mounted upright on the first circumference, and
• the slit having a U-like shape or a V-like shape with an opening portion directed to an end portion of the holding plate is formed around a position where each of the substrate support bodies are mounted upright on the second circumference.