US Patent 7729170 Semiconductor device and its control method

A semiconductor device includes sectors having memory cells connected to local word lines, decoders selecting the sectors, and a circuit generating, in erasing of a selected sector, a control signal that causes a corresponding one of the decoders associated with the selected sector to be temporarily unselected. Each of the sectors includes a pull-up transistor that is driven by a corresponding one of the decoders via a corresponding one of global word lines connecting the sectors and drives one of the local word lines, and the pull-up transistor is kept OFF by the control signal.