A 0.7-MU-M-PITCH DOUBLE LEVEL AL INTERCONNECTION TECHNOLOGY FOR 1-GBIT DRAMS USING SIO2 MASK AL ETCHING AND PLASMA-ENHANCED CHEMICAL-VAPOR-DEPOSITION SIOF

A 0.7-mu m-pitch double level aluminum (Al) interconnection technology on a 1-mu m-high step is established for 1-Gbit dynamic random access memories (DRAMs). A SiO2 film which has a high resistance to Al etchi ng was used as the mask layer. 0.35-mu m-width Al wirings were fabrica ted even on a 1-mu m-high step. 0.2-mu m-spaces (aspect ratio=2.5) bet ween the taper shaped Ai lines ri ere filled, for the first time, by p lasma enhanced chemical vapor deposition (PECVD) fluorine doped silico n oxide (SiOF) film (epsilon=3.9). The SiOF film capped with the PECVD SiO2 film has enough stability for the process integration. It was co nfirmed that these technologies can be applied to a double level Al in terconnection using a 0.3-mu m-diameter tungsten (W) plug.