METHOD FOR FORMING ALIGNMENT KEY OF SEMICONDUCTOR MEMORY DEVICE

摘要

PURPOSE: A method for forming an alignment key of a semiconductor memory device is to prevent a material for the formation of storage node from being lifted at an alignment key region during the etch process of the storage node. CONSTITUTION: A method for forming an alignment key of a semiconductor memory device comprises the steps of: forming a first insulating layer(132) on entire region of a semiconductor substrate including an alignment key region(130); etching the first insulating layer to form a bit line contact hole and to expose a selected region of the alignment key region; forming a bit line(138) of a first conductive layer on the resultant substrate; depositing a second insulating layer(140), a silicon nitride layer(144) and a third insulating layer in the named order on the resultant substrate; etching the third insulating layer and the underlying silicon nitride layer until a surface of the second insulating layer and a surface of the second insulating layer of the alignment key region are exposed to form a storage node contact hole and an opening; and forming a second conductive layer along the surface of the storage node contact hole and the opening.