Enabling interconnect scaling with Spacer-Defined Double Patterning (SDDP)

Line Edge Roughness (LER) correlation improves the interconnect Time-Dependent Dielectric Breakdown (TDDB) lifetime significantly with respect to non-correlated interconnect based on simulation [M. Stucchi, P. Roussel, Z. Tőkei, S. Demuynck, G. Groeseneken, IEEE Trans. Device Mater. Reliab. 99 (2011)] [1]. On the other hand, 50% Line Edge Roughness (LER) correlation has been observed experimentally after spacer formation in 20 nm half pitch (HP) interconnects using a Spacer-Defined Double Patterning (SDDP) approach. Comparisons of breakdown field distribution and TDDB lifetime for SDDP patterned 20 nm HP and Litho-Etch-Litho-Etch (LELE) patterned 35 nm HP Cu interconnect confirm that the SDDP approach offers potential benefits for TDDB lifetime, which enable future interconnect scaling.