초록 ▼

An improved dual damascene structure, and process for manufacturing it, are described in which the via hole is first lined with a layer of silicon nitride prior to adding the diffusion barrier and copper. This allows use of a barrier layer that is thinner than normal (since the silicon nitride liner

An improved dual damascene structure, and process for manufacturing it, are described in which the via hole is first lined with a layer of silicon nitride prior to adding the diffusion barrier and copper. This allows use of a barrier layer that is thinner than normal (since the silicon nitride liner is an effective diffusion barrier) so that more copper may be included in the via hole, resulting in an improved conductance of the via. A key feature of the process that is used to make the structure is the careful control of the etching process. In particular, the relative selectivity of the etch between silicon oxide and silicon nitride must be carefully adjusted.

대표청구항 ▼

1. A dual damascene structure, comprising:a first layer of silicon oxide on a first layer of silicon nitride; a second layer of silicon nitride on said first layer of silicon oxide; a second layer of silicon oxide, having an upper surface, on said second silicon nitride layer; a trench, having a wid

1. A dual damascene structure, comprising:a first layer of silicon oxide on a first layer of silicon nitride; a second layer of silicon nitride on said first layer of silicon oxide; a second layer of silicon oxide, having an upper surface, on said second silicon nitride layer; a trench, having a width and interior walls, extending downward from the upper surface, through the second silicon nitride and silicon oxide layers into the first silicon oxide layer; a tubular structure of silicon nitride, having a maximum outside dimension that is less than said trench width and having interior walls, overlapped by the trench and extending downwards therefrom through the first layers of silicon oxide and silicon nitride, as far as a lower-level layer of damascene wiring; a barrier layer on the interior walls of the trench, the tubular structure, and the lower-level damascene wiring layer; and copper, over said barrier layer, that fills said tubular structure and said trench to the level of said upper surface.