| 摘要 |
PURPOSE:To simply discriminate an identification mark from other marks and chip patterns in reading and to use a wafer effectively, by a method wherein an identification mark is applied to that position in the peripheral part of a substantially circular wafer having a cut part in a part thereof which is a predetermined distance away from the cut part, and the identification mark is read in relation to the detection of the cut part. CONSTITUTION:With a wafer 1 rotated by a motor 3 through a stage 2, when a point A in a cut portion S comes directly below a light source 4L, a control signal generator circuit 8 generates a control signal and continues to send the signal to a gate circuit 7 until a point B in the cut part S comes directly below the light source 4L. In the meantime, an identification mark provided on an imaginary circle F on the wafer (1) is irradiated with a light beam from a light source 5L, and a reflected light corresponding to the identification mark is detected by a photoelectric detector 5D. The output of the detector 5D is sent to the gate circuit 7 through a pulse generator 6. During the period in which the control signal is sent from the control signal generator circuit 8, the gate circuit 7 delivers to an electronic computer 9 a pulse signal corresponding to the identification mark sent from the pulse generator 6. The computer 9 decodes the pulse signal to identify the kind of the wafer. |
