Tribo-Electrochemical Considerations for Assessing Galvanic Corrosion Characteristics of Metals in Chemical Mechanical Planarization

The manufacturing of integrated circuits involves multiple steps of chemical mechanical planarization (CMP) involving different materials. Mitigating CMP-induced defects is a main requirement of all CMP schemes. In this context, controlling galvanic corrosion is a particularly challenging task for p...

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Main Authors: Kassapa U. Gamagedara, Dipankar Roy
Format: Article
Language:English
Published: MDPI AG 2025-04-01
Series:Electrochem
Subjects:
Online Access:https://www.mdpi.com/2673-3293/6/2/15
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author Kassapa U. Gamagedara
Dipankar Roy
author_facet Kassapa U. Gamagedara
Dipankar Roy
author_sort Kassapa U. Gamagedara
collection DOAJ
description The manufacturing of integrated circuits involves multiple steps of chemical mechanical planarization (CMP) involving different materials. Mitigating CMP-induced defects is a main requirement of all CMP schemes. In this context, controlling galvanic corrosion is a particularly challenging task for planarizing device structures involving contact regions of different metals with dissimilar levels of corrosivity. Since galvanic corrosion occurs in the reactive environment of CMP slurries, an essential aspect of slurry engineering for metal CMP is to control the surface chemistries responsible for these bimetallic effects. Using a CMP system based on copper and cobalt (used in interconnects for wiring and blocking copper diffusion, respectively), the present work explores certain theoretical and experimental aspects of evaluating and controlling galvanic corrosion in barrier CMP. The limitations of conventional electrochemical tests for studying CMP-related galvanic corrosion are examined, and a tribo-electrochemical method for investigating these systems is demonstrated. Alkaline CMP slurries based on sodium percarbonate are used to planarize both Co and Cu samples. Galvanic corrosion of Co is controlled by using the metal-selective complex forming functions of malonic acid at the Co and Cu sample surfaces. A commonly used corrosion inhibitor, benzotriazole, is employed to further reduce the galvanic effects.
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spelling doaj-art-2dffd6a34ad64e0d84e022df1cc380672025-08-20T03:24:32ZengMDPI AGElectrochem2673-32932025-04-01621510.3390/electrochem6020015Tribo-Electrochemical Considerations for Assessing Galvanic Corrosion Characteristics of Metals in Chemical Mechanical PlanarizationKassapa U. Gamagedara0Dipankar Roy1Department of Physics, Clarkson University, Potsdam, NY 13699-5820, USADepartment of Physics, Clarkson University, Potsdam, NY 13699-5820, USAThe manufacturing of integrated circuits involves multiple steps of chemical mechanical planarization (CMP) involving different materials. Mitigating CMP-induced defects is a main requirement of all CMP schemes. In this context, controlling galvanic corrosion is a particularly challenging task for planarizing device structures involving contact regions of different metals with dissimilar levels of corrosivity. Since galvanic corrosion occurs in the reactive environment of CMP slurries, an essential aspect of slurry engineering for metal CMP is to control the surface chemistries responsible for these bimetallic effects. Using a CMP system based on copper and cobalt (used in interconnects for wiring and blocking copper diffusion, respectively), the present work explores certain theoretical and experimental aspects of evaluating and controlling galvanic corrosion in barrier CMP. The limitations of conventional electrochemical tests for studying CMP-related galvanic corrosion are examined, and a tribo-electrochemical method for investigating these systems is demonstrated. Alkaline CMP slurries based on sodium percarbonate are used to planarize both Co and Cu samples. Galvanic corrosion of Co is controlled by using the metal-selective complex forming functions of malonic acid at the Co and Cu sample surfaces. A commonly used corrosion inhibitor, benzotriazole, is employed to further reduce the galvanic effects.https://www.mdpi.com/2673-3293/6/2/15benzotriazolemalonic acidchemical–mechanical planarizationtribo-electrochemistryCMP selectivitycobalt-based diffusion barrier
spellingShingle Kassapa U. Gamagedara
Dipankar Roy
Tribo-Electrochemical Considerations for Assessing Galvanic Corrosion Characteristics of Metals in Chemical Mechanical Planarization
Electrochem
benzotriazole
malonic acid
chemical–mechanical planarization
tribo-electrochemistry
CMP selectivity
cobalt-based diffusion barrier
title Tribo-Electrochemical Considerations for Assessing Galvanic Corrosion Characteristics of Metals in Chemical Mechanical Planarization
title_full Tribo-Electrochemical Considerations for Assessing Galvanic Corrosion Characteristics of Metals in Chemical Mechanical Planarization
title_fullStr Tribo-Electrochemical Considerations for Assessing Galvanic Corrosion Characteristics of Metals in Chemical Mechanical Planarization
title_full_unstemmed Tribo-Electrochemical Considerations for Assessing Galvanic Corrosion Characteristics of Metals in Chemical Mechanical Planarization
title_short Tribo-Electrochemical Considerations for Assessing Galvanic Corrosion Characteristics of Metals in Chemical Mechanical Planarization
title_sort tribo electrochemical considerations for assessing galvanic corrosion characteristics of metals in chemical mechanical planarization
topic benzotriazole
malonic acid
chemical–mechanical planarization
tribo-electrochemistry
CMP selectivity
cobalt-based diffusion barrier
url https://www.mdpi.com/2673-3293/6/2/15
work_keys_str_mv AT kassapaugamagedara triboelectrochemicalconsiderationsforassessinggalvaniccorrosioncharacteristicsofmetalsinchemicalmechanicalplanarization
AT dipankarroy triboelectrochemicalconsiderationsforassessinggalvaniccorrosioncharacteristicsofmetalsinchemicalmechanicalplanarization