Dual damascene patterning of polymer interlayer dielectrics

We unveil an innovative and manufacturable process technique to pattern dual damascene structures in polymer interlayer dielectric (ILD) without the need for either a permanent hardmask or an embedded etch stop (ES) layer. We introduce a sacrificial hardmask (SAM) and a sacrificial via fill (SAVIL) material to enable the patterning process. Since the hardmask is sacrificial, it is removed at the end of the patterning process without compromising the overall dielectric value of the ILD. The utilization of the SAVIL material provided the trench lithography step with a hole-free, and planar substrate. We demonstrate patterning of dual damascene structures using SAM/SAVIL in a via-first integration scheme through a comparative patterning performance between the SAM/SAVIL-assisted dual damascene patterning and the dual hardmask approach used most in the industry.