Methods for processing machine-readable forms or documents of non-fixed format are disclosed. Since a gate electrode of an n-channel type MISFET and a gate electrode of a p-channel type MISFET are of mutually different conductivity types, they are separated to prevent the mutual diffusion of the impurities and are electrically connected to each other via a metallic wiring formed in the following steps. The detection can include direct or indirect detection of voltage or current.