Sub-quarter micron copper interconnects through dry etching process and its reliability

Copper is the major candidate material of post-Al alloys in deep sub-micron region, because of low resistivity and long electromigration lifetime. Recently, ion milling and chemical mechanical polishing (CMP) have been applied to fine Cu interconnects, and these techniques can avoid the difficulty of etching Cu caused by hardly subliming etching-products. However, these are not necessarily the well-established technique for ULSI process. Our approach is modification of the high temperature dry etching, which includes the self-aligned passivation technique. In this work, we have formed TiN/Cu/TiN multilayered interconnects of sub-quarter micron width using the modified dry etching technique, and evaluated the resistance to electromigration damage (EMD).<>