Beol integration scheme for copper cmp to prevent dendrite formation

Abstract

Disclosed herein are various methods of forming copper-based conductive structures on integrated circuit devices by performing a copper deposition process to fill the trench or via with copper, which can be performed by fill, plating or electroless deposition. Copper clearing of copper overburden is performed using CMP to stop on an existing liner. Copper in the trenches or vias is recessed by controlled etch. An Nblok cap layer is deposited to cap the trenches or vias so that copper is not exposed to ILD. Nblok overburden and adjacent liner is then removed by CMP. Nblok cap layer is then deposited. The proposed approach is an alternative CMP integration scheme that will eliminate the exposure of copper to ILD during CMP, will prevent any dendrite formation, can be used for all metal layers in BEOL stack, and can be utilized for multiple layers, as necessary, whenever copper CMP is desired.