Provided is a manufacturing method for a solid-state image pickup device, which enables easily manufacturing a thin-type solid-state image pickup device at a wafer level. A method of dehumidifying air introduced into an aircraft fuel tank via a ventilation system includes directing atmospheric air through a dehumidifying device disposed in flow communication between a vent of the ventilation system and the fuel tank, which removes water vapour from the air flowing from the vent towards the fuel tank. In various embodiments, the master circuit might utilize high threshold voltage, standard threshold voltage, or low threshold voltage transistors.