Abstract: A method of identifying individual semiconductor devices with a unique inscription during the manufacturing process for the semiconductor devices. Each individual semiconductor device is marked during a final lithographic stepping exposure with a direct write laser mounted either in the stepper in the lithographic system working concurrently with the stepping fields during the final metal layer lithographic stepping exposure or during a post stepping pre-development treatment. The marking on the devices includes device identification, lot number and die number.

Abstract: A generated signal is passed through an elongated signal conveying element positioned preferably perpendicular to the surface of a fluid the level of which is to be measured. The signal is directed from the signal conveying element to a detector element which senses the signal output from the signal conveying element. The signal output detected in an optical embodiment varies logarithmically with the depth of immersion of the signal conveying element into the fluid. A preferred embodiment employs an electromagnetic wave, e.g., light, signal which passes through a light pipe signal conveying element. By nearly matching the light pipe index of refraction with that of the fluid, a predetermined precentage of the wave is lost into the fluid each time the light is reflected further along the pipe.