Dependency of dishing on polish time and slurry chemistry in Cu CMP

V. Nguyen, H. Vankranenburg, P. Woerlee

Research output: Contribution to journalConference articlepeer-review

69 Citations (Scopus)

Abstract

In this paper the influences of slurry chemistry and thickness of the copper layer on dishing will be discussed. The dishing is studied for different patterns and variable polishing times. We found that the concentration of the oxidizer and the thickness of copper layer have a strong impact on dishing. The larger Cu features develop dishing at a higher rate than smaller structures during overpolishing. The experimental results lead to the following hypothesis for the Cu removal and surface passivation. The oxidizer (H2O2) reacts with Cu in an acidic slurry (pH 4) and Cu2+ ions are formed. The anions of the carboxylic acid react with Cu2+ ions and form an insoluble salt (R(COO)2Cu) which passivates the surface. This passivation layer is removed in protruding areas by mechanical abrasion. Once removed from the surface, the `metallic soap' particles are swept away by the turbulent motion in the slurry .

Original languageEnglish
Pages (from-to)403-410
Number of pages8
JournalMicroelectronic Engineering
Volume50
Issue number1-4
DOIs
Publication statusPublished - Jan 2000
Externally publishedYes
Event1999 3rd Eropean Workshop on Materials for Advanced Metallization (MAM'99) - Ostende, Belg
Duration: 7 Mar 199910 Mar 1999

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