Buried Power Rail Metal exploration towards the 1 nm Node

Authors:

11 December 2021

conference paper
Published by Institute of Electrical and Electronics Engineers (IEEE)

p. 22.5.1-22.5.4
DOI:10.1109/iedm19574.2021.9720684

Abstract

This work reports metal exploration for buried power rail (BPR) and Via-to-BPR (VBPR) towards the 1 nm node. For tungsten, which is the first choice of BPR metal at the 3 nm node, we optimize W metallization stack to minimize line resistivity, together with ways to reduce W-BPR - W-VBPR contact resistance (R). For scaled BPR CDs at the 2 nm and 1 nm nodes, we introduce molybdenum at the BPR level and benchmark its R and electromigration against W and Ru metallization. Additionally, Mo dry & wet, selective etch processes to enable Mo-BPR recess in fin/STI stack at fin pitch 24 nm, and a Mo wet clean process for VBPR contact formation are also demonstrated.

Keywords

RAILS
ELECTROMIGRATION
METALLIZATION
TUNGSTEN
CONDUCTIVITY
CONTACT RESISTANCE
BUSINESS PROCESS RE-ENGINEERING

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