| 摘要 |
A different method is provided for forming high aspect ratio damascene structures with an integrated approach of combining electroless plating with physical vapor deposition of copper. A dual damascene structure, having a trench opening and a via opening, is first formed over a metal line on a substrate. The inside walls of the dual structure is lined with a diffusion barrier layer. Then, nitride spacers are formed on the inside walls of both the trench opening and the via opening. The via opening is further lined with a displacement, or, seed, layer. This is followed by forming electroless copper in the via opening, and hence a copper plug. A barrier metal is now formed over both the copper plug and the inside walls of the trench opening. Copper is next deposited over the barrier metal inside the trench, and including over the copper metal plug, using physical vapor deposition (PVD). Any excess metal is subsequently removed by CMP, thus forming a copper dual damascene interconnect that is highly conformable for high aspect ratios, and also void-free and reliable.
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