Copper dry etching technique for ULSI interconnections

As a consequence of the well-known difficulties in reactive dry Cu patterning only a small number of processes has been published world-wide. Using a simple Cl-2 based chemistry including an intense ion bombardment as an alternative approach, the formation of thick sidewall films during etching (as proposed by other groups) is not necessary. As will be shown, a copper dry etching technique for interconnections down to 0.2 mu m has been developed. The line resistance of PVD- and CVD-Cu has been measured indicating a good correlation with the calculated values. Finally, first electromigration resistance measurements of PVD-Cu lines have been performed.