A semiconductor integrated circuit is composed of a memory array, sense amplifiers, a first and second drive circuits, and a sense amplifier control circuit. The master device may control data transfer between the master device and the slave device. Vertical etch process steps and opening enlarging process steps are then performed in an alternating manner until the trench has been etched to a desired depth. In some cases, the housing may include a ring that may be moved to adjust a tolerance between the ring and the impeller.