Formation of wire line involves forming bit line after forming second contact used as storage node contact so that electrical connection between second contact and lower semiconductor substrate can be reliably formed

摘要

A wire line is formed by forming a bit line after forming a second contact used as a storage node contact so that electrical connection between a second contact and a lower semiconductor substrate can be reliably formed. Formation of a wire line by a damascene involves forming a first insulating layer on a semiconductor substrate; etching the first insulating layer to form a contact hole; forming a first conductive layer over the first insulating layer that fills the contact hole; patterning the first conductive layer; forming a storage node contact that fills the contact hole and is electrically connected to the semiconductor substrate; forming a hard mask over the storage node contact; etching the first insulating layer using the hard mask as an etch mask to form a trench in the first insulating layer; forming a bit line that is electrically connected to the semiconductor substrate in the trench; forming a second insulating layer that covers the bit line; planarizing the second insulating layer and the hard mask; and forming a storage node on the storage node contact.