Metal-Diamond-Metal Planar Structures for off-angle UV Beam Positioning with High Lateral Resolution

A position sensitive detector (PSD) for deep-UV excimer laser has been realised and characterised. CVD diamond was chosen as the active material for its high cohesive energy that ensures good reliability under the high power density of excimer laser radiation. Besides, the high gap-energy of diamond ensures blindness to visible radiation and a high sensitivity to the UV radiation used in the last generation of photolithographic tools. The device is based on a voltage division scheme that makes possible to obtain the sensitivity to the beam position while reducing the sensitivity to its intensity. Two contact structures are compared, and the performances of these detectors are evaluated in term of non-linearity, position measurement error and position sensitivity.