TRENCH LITHOGRAPHY PROCESS

摘要

A process of forming an integrated circuit using a dual damascene interconnect process by etching a via hole in an ILD and filling the via hole with a sacrificial via fill material. A trench etch hard mask layer is formed over the ILD. An inorganic hard mask layer is formed over the trench etch hard mask layer. The inorganic hard mask layer is etched to form an etch mask for the trench etch hard mask layer, which is subsequently etched to form an etch mask for the trench etch process. The sacrificial via fill material etches at a comparable rate to the ILD layer. The trench etch hard mask layer is removed and the sacrificial via fill material is removed from the via hole.