Dynamic random access memory device and method for fabricating the same

摘要

A semiconductor memory device with a capacitor-over-bitline (COB) structure and a method for fabricating the same. The semiconductor memory device includes a transistor having a gate electrode formed on a gate insulating layer on a semiconductor substrate and having source and drain regions formed on the surface of the substrate and separated from each other by the gate electrode, a first interlayer insulating layer formed over the substrate including the transistor; a bitline formed over the first interlayer insulating layer; and a second interlayer insulating layer formed over the substrate including the bitline, for insulating the bitline from a storage node of a capacitor. A surface of the second interlayer insulating layer is planarized by a chemical-mechanical polishing (CMP) process so as to be substantially parallel to a surface of the substrate including the bitline.