Browsing by Author "Dordi, Yezdi"

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Interface Engineering Strategy Utilizing Electrochemical ALD of Cu-Zn for Enabling Metallization of Sub-10 nm Semiconductor Device Nodes
(2019-08-28)
Joi, Aniruddha
;
Venkatraman, Kailash
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Tso, Kuang-Chih
;
Dictus, Dries
;
Dordi, Yezdi
A novel interface engineering approach, utilizing electrochemical atomic layer deposition (e-ALD) of Cu(Zn) on a Ru liner, is presented for enabling the metallization of sub-10 nm interconnects in future semiconductor devices. Upon thermal treatment, Zn present in the e-ALD Cu layer at similar to 0.8 at.% is shown to diffuse through the Ru liner and react with the SiO2 to form a Zn-silicate layer at the Ru-SiO2 interface. This 'self-forming' interfacial layer provides adhesion enhancement to the Ru-SiO2 interface and serves as a diffusion barrier retarding Cu diffusion into the SiO2 layer while enabling void-free gap-filling of high aspect ratio trench structures. Absorption Near-Edge Spectroscopy and Extended X-ray Absorption Fine Structure analyses confirm that the self-formed barrier layer is composed primarily of Zn2SiO4. The interface engineering approach utilizing Cu(Zn) presented herein offers several potential advantages over traditional Mn-based self-forming barrier approaches, i.e., scalability to narrower dimensions and minimal impact to interconnect resistance. (C) The Author(s) 2019. Published by ECS.
Polydopamine and Its Composite Film as an Adhesion Layer for Cu Electroless Deposition on SiO2
(2020-03-09)
Chou, Shih-Cheng
;
Chung, Wei-An
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Fan, Tzu-Ling
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Dordi, Yezdi
;
Koike, Junichi
We explore dopamine (DA) and its mixtures with polyethylene glycol (PEG) or polyethylenimine (PEI) as an adhesion layer for bonding between Cu and SiO2. The DA is oxidized to form polydopamine (PDA) which deposits as aggregates on SiO2 surface with notable surface roughness. After mixing with PEG or PEI, the morphology of PDA aggregates is altered considerably. Electroless Cu deposition in a mild alkaline bath is employed to deposit Cu atop the adhesion layer. The Cu films reveal an fcc lattice with (111) preferred orientation and their thickness was around 650 nm. From measurements of four-point probe, breaking strength, and tape-peeling tests, the PDA/PEG mixture reveals impressive performance serving as a strong adhesive for robust Cu bonding. We attribute the unique adhesive ability of PDA/PEG to the hydrogen bonds established between the catechol and amine groups of DA with PEG that renders desirable film formation on the SiO2 surface for optimized interaction between Cu and SiO2. (C) 2020 The Author(s). Published on behalf of The Electrochemical Society by IOP Publishing Limited.
Pulse electrodeposition of copper-manganese alloy in deep eutectic solvent
(2018-04-25)
Chiang, Wei-Shen
;
Huang, Jun-Qian
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Chen, Po-Chun
;
Wu, Pu-Wei
;
Joi, Aniruddha
Copper-manganese alloy has been established to improve resistance toward electromigration for interconnects. In this work, we employ a deep eutectic solvent (DES) to formulate a nonaqueous electrolyte for pulse current electrodeposition of Cu-Mn alloyed film. Using impedance spectroscopy to record ionic conductivities of DES-based electrolytes, we determine the optimized bath with a Cu/Mn molar ratio of 1:20. We produce an uniform, smooth, and composition-controllable CuMn alloyed film after exploring various pulsing parameters. Signals from X-ray diffractometer (XRD) suggest successful alloying of Cu and Mn with minor presence of MnO2. Profiles from X-ray photoelectron spectroscopy (XPS) validate the metallic nature of Mn from the as-deposited film. Upon Ar annealing, both XRD and XPS exhibit strong signals of MnO2 formation. In addition, images from transmission electron microscope and qualitative elemental chemical mapping indicate Mn atoms in CuMn alloy either diffuse through the underlying Cu seed layer and segregate at the Cu/SiO2 interface, or migrate toward the external surface forming MnO2. (C) 2018 Elsevier B.V. All rights reserved.