A tribochemical study of ceria-silica interactions for CMP

Jeremiah T. Abiade, Suresh Yeruva, Wonseop Choi, Brij M. Moudgil, Dhananjay Kumar, Rajiv K. Singh

Research output: Contribution to journalArticlepeer-review

45 Scopus citations

Abstract

Shallow trench isolation (STI) allows tighter device packing and reduced chip area for isolation. STI is critically dependent on the global planarity that is only possible using chemical mechanical polishing (CMP). Ceria-based slurries are considered the most promising candidates for STI CMP. Despite decades of use in glass polishing, the unique characteristics of ceria slurries are not well understood. In this study, we have conducted force measurements and tribological tests using an atomic force microscope (AFM) and a scanning electron microscope to investigate pH-dependent ceria-silica and silica-silica interactions that occur during CMP. Our studies confirm the effect of hydrolysis at high pH during silica-silica abrasion. An additional physicochemical contribution to ceria-silica polishing is identified and discussed. Furthermore, a strong correlation was observed between the AFM based studies and in situ friction force measurements during CMP.

Original languageEnglish
Article number068611JES
Pages (from-to)G1001-G1004
JournalJournal of the Electrochemical Society
Volume153
Issue number11
DOIs
StatePublished - 2006
Externally publishedYes

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