| 摘要 |
PURPOSE:To prevent the fall of the yield of wafers and the sticking of extraneous substances on the surfaces thereof, by forming a mark such as a hole or a groove in a part of the surface of each wafer while maintaining the shape thereof to be round. CONSTITUTION:A very small hole 2a is formed as a mark in a part of the periphery of the surface of a round wafer 2. This hole 2a may be formed on the back side of the wafer 2. A groove 3a in the direction of the diameter may also be formed as a mark instead of said hole. In either case, the hole 2a or the groove 3a is formed to be small so as not to lower the yield of a circuit pattern which is formed on the surface of the wafer. In the case of the wafer 2 having the hole 2a formed as the mark, the positioning thereof in the directions X and Y is performed by utilizing directional air 9, and the mark 2a is detected by a mark sensor 11 while the wafer 2 is rotated by rotating rollers 10 which are made to contact with the wafer by said positioning. Then, the wafer is stopped at a position of rotation whereat the mark 2a is detected by the mark sensor 11, and thereby the positioning of the wafer in the direction theta is completed. |
