Patent ID: 6592673
Filing Date: 2003-07-15
Classification: H01L

Abstract:
An apparatus capable of detecting a proper positioning of a substrate on a support, the apparatus comprising:(a) a support adapted to support the substrate on a receiving surface, the support comprising a window adjacent to a peripheral edge of a properly positioned substrate, and the window comprising a material that is substantially transparent to a wavelength of a radiation comprising ultraviolet light, infra-red light, visible light or X-rays; (b) a radiation source adapted to project the radiation having the wavelength over the entire receiving surface of the support, and through the window in the support in a path adjacent to the peripheral edge of the substrate; and (c) a radiation sensor in a path of the radiation after the radiation passes through the window in the support, the radiation sensor adapted to detect a proper positioning of the substrate on the support by measuring an intensity of the radiation, wherein the radiation sensor and radiation source are positioned such that the radiation passing through the window reaches the radiation sensor when the substrate is properly positioned and the radiation is partially or entirely blocked by the substrate when the substrate is improperly positioned, or vice versa.