CHARGE TRANSFER DEVICE HAVING INPUT PROTECTIVE CIRCUIT AND MANUFACTURE THEREOF

摘要

PROBLEM TO BE SOLVED: To prevent variations in fixed amt. of charges due to external influences, e.g. electrostatic charges by connecting charge transfer electrodes to a first input protective circuit having a first clamp level and second input protective circuit having a second clamp level higher than that of the first. SOLUTION: In a wafer processing step, first and second charge transfer electrodes 28A, 28B are connected to first and second input protective circuits 21A, 21B, respectively, through metal wirings. The second protective circuit has a second clamp level higher than that of the first protective circuit. They are initialized at a high clamp level prior to the input protective circuit having a lower clamp level being connected to outer lead pins 26. Then this circuit is connected to the pins 26. This provides a low clamp level stage for suppressing the variation of the potential well depth, due to the electrostatic charges, etc.