| 摘要 |
PURPOSE:To obtain a device which can make a very accurate pre-alignment for various types of semiconductor wafers, causes no problem such as dust production, and has a relatively low cost, by setting the radiation by a light emitting element in a slanted condition relative to a wafer so as to radiate a light to the edge of the wafer. CONSTITUTION:In a device which optically detects the alignment of a wafer 6 to a predefined position with a light emitting element 3 and a photo detector 4, the radiation by the light emitting element 3 is set in a slanted condition relative to the wafer 6 so that the radiation is applied to the edge of the wafer 6. Alternatively, in a device which optically detects the alignment of a wafer to a predefined position by a light emitting element 14 and a photo detector 16, the light emitting element 14 is disposed on one of the two sides of a wafer 13 and the photo detector 16 is on the other. And, the amount of the light received by the photo detector 16 is measured to calculate the center position and the amount of eccentricity of the wafer 13. Then, the eccentricity of the wafer 13 is corrected and the positioning of the orientation flatness of the wafer 13 is determined for pre-alignment of the wafer 13. |
