<p>PURPOSE: A substrate processing device is provided to distribute accumulated heat by installing a light diffusion lens on a position corresponding to the center of a substrate receiver which has accumulated heat. CONSTITUTION: A chamber(112) provides a reactive space. A substrate receiver(120) is positioned on the reactive space and receives a substrate. A heating unit includes a lamp, a reflective plate, and an optical lens. The lamp is positioned on the lower side of the chamber and heats the substrate receiver. The reflective plate reflects the light from the lamp. An optical lens is positioned on the lamp.</p>
