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Microchip manufacture. Technician putting a silicon wafer into an oven for heat treatment. He is wearing a mask and gloves because the wafer must be kept very clean. The wafer is a single crystal of silicon produced with precisely controlled structure, purity and doping (addition of trace elements) to give it the desired electrical properties. Wafers are heated to remove solvent from previous steps, and to bake on chemicals used in etching the microchip's circuitry. Photographed in a Philips factory, Caen, France. (KEYSTONE/SCIENCE PHOTO LIBRARY/PHILIPPE PSAILA)