Advanced BEOL Interconnects

Feasibility of single damascene Cu BEOL nanowires with TaN/Ta barrier (i.e. omitting a CVD-Co liner) was studied. Successful Cu gap-fill in 36 nm pitch trenches demonstrated 30% line resistance (Line-R) reduction vs. leading-edge Cu with conventional TaN/Co liner. This was attributed to larger Cu vo...

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Main Authors: Nogami, Takeshi, Gluschenkov, Oleg, Sulehria, Yasir, Nguyen, Son, Huang, Huai, Lanzillo, Nick A, DeSilva, Anuja, Mignot, Yann, Church, Jennifer, Lee, Joe, Bhosale, Prasad, Patlolla, Raghuveer, Sil, Devika, Shobha, Hosadurga, Kelly, James, Li, Juntao, Demarest, James, Simon, Andrew, Clevenger, Lawrence, Dan Edelstein, Brown Peethala, Haran, Bala
Format: Conference Proceeding
Language:English
Subjects:
Conferences
Grain boundaries
Resistance
Scattering
Technological innovation
Wires
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Summary:Feasibility of single damascene Cu BEOL nanowires with TaN/Ta barrier (i.e. omitting a CVD-Co liner) was studied. Successful Cu gap-fill in 36 nm pitch trenches demonstrated 30% line resistance (Line-R) reduction vs. leading-edge Cu with conventional TaN/Co liner. This was attributed to larger Cu volume fraction and 15% lower intrinsic Cu resistivity. In order to assess the Line-R crossover point, comparable Ru nanowires were estimated through analysis of electron scattering components, based on Rs of blanket Ru films. The calculation predicts Line-R of subtractive-etched Ru lines (larger grains) crosses conventional Cu with TaN/Co liner at 12 nm linewidth, but never crosses Cu with TaN/Ta liner. Analysis of electron scattering components shows the resistivity of Ru lines will be dominated by grain boundary scattering, suggesting that the key for subtractive-etched Ru wires crossing over Cu would be innovations that enhance grain growth of blanket Ru films.
ISSN:2380-6338
DOI:10.1109/IITC47697.2020.9515628