Integration of 20nm half pitch single damascene copper trenches by spacer-defined double patterning (SDDP) on metal hard mask (MHM)

Spacer defined double patterning (SDDP) enables further pitch scaling using 193nm immersion lithography. This work aims to design and generate 20nm half pitch (HP) back-end-of-line test structures for single damascene metallization using SDDP with a 3-mask flow. We demonstrated patterning and metallization of 20nm HP trenches in silicon oxide with TiN metal hard mask (MHM).