| 摘要 |
PURPOSE:To prevent the deterioration of the accuracy of detection by measuring the layer resistance of thin-films at least two points in each wafer while comparing the layer resistance of thin-films on wafers flowing at front and rear positions during continuous operation in continuous film-formation operation. CONSTITUTION:The layer resistance of wafers measured by layer-resistance detecting sensors 1, 2 is converted as voltage corresponding to layer resistance by R/V conversion circuits 3, 4 and compared by a comparison circuit 5 and the difference is outputted 9. Layer resistance measured by the sensor 1 is A/D converted 6 and transmitted over an arithmetic circuit 7, and compared with the resistance value of a thin-film on the wafer immediately before the wafer, layer resistance thereof is measured by the sensor 1 and memorized to a memory section 8, and the difference is outputted as an output 10 from the arithmetic circuit. The data of the memory section 8 is updated with the latest one at that time. The comparison-circuit output 9 and the arithmetic-circuit output 10 are transmitted over a control section 11, and a keeping within an allowance inputted from an allowance input section 12 is decided. Accordingly, the layer resistance of thin-films on the wafers passing at front and rear positions during continuous operation is compared, thus preventing the deterioration of the accuracy of detection.
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