Fundamental studies on the removal of copper in hydroxylamine based chemistries of interest to copper chemical-mechanical planarization

Persistent Link:
http://hdl.handle.net/10150/280420
Title:
Fundamental studies on the removal of copper in hydroxylamine based chemistries of interest to copper chemical-mechanical planarization
Author:
Huang, Wayne Hai-Wei
Issue Date:
2003
Publisher:
The University of Arizona.
Rights:
Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.
Abstract:
The advancement of IC technology has led to an increasing demand for faster and cheaper microelectronic devices. One of the key processing steps in fabricating ultra-large scale integration devices is copper chemical-mechanical planarization (CMP). Traditional copper CMP slurries use hydrogen peroxide as an oxidant. A novel copper CMP slurry based on hydroxylamine chemistry is being considered as an alternative to hydrogen peroxide based slurries. The main goal of the research reported in this dissertation is to understand the removal of copper in hydroxylamine based chemistries. Copper removal experiments were performed on a regular CMP tool and a specially designed electrochemical abrasion cell (EC-AC). The effects of applied pressure and abrasion speed were investigated on both tools. The electrochemistry of copper in hydroxylamine based chemistry was investigated using electrochemical techniques on the EC-AC tool. The techniques include electrochemical polarization and voltammetry. The effects of solution pH and hydroxylamine concentration on the polarization of copper were systematically investigated. The fate of hydroxylamine and other nitrogen-based species were studied using capillary electrophoresis chromatography. The removal rates of copper obtained from a regular CMP tool were twice as much as the rates obtained from the EC-AC tool. However, the removal rates from both tools showed the same trend with respect to pH. Interestingly, a maximum peak in copper removal rates occurs at a pH value of 6, and a significant decrease in rates occur at pH values deviating from 6. The copper removal results obtained from the EC-AC tool with and without abrasion showed that the high removal rate at pH 6 is largely due to chemical attack. The reactions involved in the oxidation of copper are dependent on the decomposition and complexation behaviors of hydroxylamine. Electrochemical analysis showed the removal of copper may be dependent on the reduction of nitric oxide (NO) to hyponitrous specie (H₂N₂O₂). Capillary electrophoresis chromatography analyses showed the consumption of hydroxylamine and species generated from the autooxidation/reduction of hydroxylamine. In slightly alkaline pH conditions, the removal of copper was predominantly due to mechanical abrasion of the surface oxide. This was supported by the potential-pH diagrams and the analysis of applied pressure and relative velocity. At pH values ranging from 3 to 5, the removal of copper was due to oxidation of Cu to Cu²⁺.
Type:
text; Dissertation-Reproduction (electronic)
Keywords:
Engineering, Materials Science.
Degree Name:
Ph.D.
Degree Level:
doctoral
Degree Program:
Graduate College; Materials Science and Engineering
Degree Grantor:
University of Arizona
Advisor:
Raghavan, Srini

Full metadata record

DC FieldValue Language
dc.language.isoen_USen_US
dc.titleFundamental studies on the removal of copper in hydroxylamine based chemistries of interest to copper chemical-mechanical planarizationen_US
dc.creatorHuang, Wayne Hai-Weien_US
dc.contributor.authorHuang, Wayne Hai-Weien_US
dc.date.issued2003en_US
dc.publisherThe University of Arizona.en_US
dc.rightsCopyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author.en_US
dc.description.abstractThe advancement of IC technology has led to an increasing demand for faster and cheaper microelectronic devices. One of the key processing steps in fabricating ultra-large scale integration devices is copper chemical-mechanical planarization (CMP). Traditional copper CMP slurries use hydrogen peroxide as an oxidant. A novel copper CMP slurry based on hydroxylamine chemistry is being considered as an alternative to hydrogen peroxide based slurries. The main goal of the research reported in this dissertation is to understand the removal of copper in hydroxylamine based chemistries. Copper removal experiments were performed on a regular CMP tool and a specially designed electrochemical abrasion cell (EC-AC). The effects of applied pressure and abrasion speed were investigated on both tools. The electrochemistry of copper in hydroxylamine based chemistry was investigated using electrochemical techniques on the EC-AC tool. The techniques include electrochemical polarization and voltammetry. The effects of solution pH and hydroxylamine concentration on the polarization of copper were systematically investigated. The fate of hydroxylamine and other nitrogen-based species were studied using capillary electrophoresis chromatography. The removal rates of copper obtained from a regular CMP tool were twice as much as the rates obtained from the EC-AC tool. However, the removal rates from both tools showed the same trend with respect to pH. Interestingly, a maximum peak in copper removal rates occurs at a pH value of 6, and a significant decrease in rates occur at pH values deviating from 6. The copper removal results obtained from the EC-AC tool with and without abrasion showed that the high removal rate at pH 6 is largely due to chemical attack. The reactions involved in the oxidation of copper are dependent on the decomposition and complexation behaviors of hydroxylamine. Electrochemical analysis showed the removal of copper may be dependent on the reduction of nitric oxide (NO) to hyponitrous specie (H₂N₂O₂). Capillary electrophoresis chromatography analyses showed the consumption of hydroxylamine and species generated from the autooxidation/reduction of hydroxylamine. In slightly alkaline pH conditions, the removal of copper was predominantly due to mechanical abrasion of the surface oxide. This was supported by the potential-pH diagrams and the analysis of applied pressure and relative velocity. At pH values ranging from 3 to 5, the removal of copper was due to oxidation of Cu to Cu²⁺.en_US
dc.typetexten_US
dc.typeDissertation-Reproduction (electronic)en_US
dc.subjectEngineering, Materials Science.en_US
thesis.degree.namePh.D.en_US
thesis.degree.leveldoctoralen_US
thesis.degree.disciplineGraduate Collegeen_US
thesis.degree.disciplineMaterials Science and Engineeringen_US
thesis.degree.grantorUniversity of Arizonaen_US
dc.contributor.advisorRaghavan, Srinien_US
dc.identifier.proquest3108914en_US
dc.identifier.bibrecord.b4482547xen_US
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