SEMI-CONDUCTOR MANUFACTURING DEVICE

摘要

PURPOSE:To recognize the position of a wafer exactly and carry the wafer exactly between the wafer in a cassette and a carrier arm by memorizing the position of the wafer in a cassette stage which is detected by a wafer detection optical sensor, according to the number of the steps of a stepping motor. CONSTITUTION:A stepping motor 6 can memorize the height position of a cassette stage 5 from the detected output 10 from a sensor 2a according to the number of steps which has driven to respective ones from the reference position of the cassette stage 5, and can also detect the number of steps between two wafers 4. The position of the cassette stage 5 where a carrier arm 1 reaches the middle position between the wafers 4 can be calculated from the memorized number of steps. Carrying the wafer 4 can be conducted even from a cassette with a major dimensional error by positioning the cassette stage 5 so that the carrier arm may reach the middle position between the wafers 4.