Improvement of thermal conductivity of electroplated copper thin-film interconnections by controlling their micro texture

Pornvitoo Rittinon, Ken Suzuki, Hideo Miura

Research output: Contribution to conferencePaper

1 Citation (Scopus)

Abstract

Copper thin films are indispensable for the interconnections in the advanced electronic products, such as TSV (Trough Silicon Via), fine bumps, and thin-film interconnections in various devices and interposers. However, it has been reported that both electrical and mechanical properties of the films vary drastically comparing with those of conventional bulk copper. The main reason for the variation can be attributed to the fluctuation of the crystallinity of grain boundaries in the films. Porous or sparse grain boundaries show very high resistivity and brittle fracture characteristic in the films. Thus, the thermal conductivity of the electroplated copper thin films should be varied drastically depending on their micro texture based on the Wiedemann-Franz's law. Since the copper interconnections are used not only for the electrical conduction but also for the thermal conduction, it is very important to quantitatively evaluate the crystallinity of the polycrystalline thin-film materials and clarify the relationship between the crystallinity and thermal properties of the films. The crystallinity of the interconnections were quantitatively evaluated using an electron back-scatter diffraction method. It was found that the porous grain boundaries which contain a significant amount of vacancies increase the local electrical resistance in the interconnections, and thus, cause the local high Joule heating. Such porous grain boundaries can be eliminated by control the crystallinity of the seed layer material on which the electroplated copper thin film is electroplated.

Original languageEnglish
DOIs
Publication statusPublished - 2014 Jan 1
EventASME 2014 International Mechanical Engineering Congress and Exposition, IMECE 2014 - Montreal, Canada
Duration: 2014 Nov 142014 Nov 20

Other

OtherASME 2014 International Mechanical Engineering Congress and Exposition, IMECE 2014
CountryCanada
CityMontreal
Period14/11/1414/11/20

ASJC Scopus subject areas

  • Mechanical Engineering

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    Rittinon, P., Suzuki, K., & Miura, H. (2014). Improvement of thermal conductivity of electroplated copper thin-film interconnections by controlling their micro texture. Paper presented at ASME 2014 International Mechanical Engineering Congress and Exposition, IMECE 2014, Montreal, Canada. https://doi.org/10.1115/IMECE2014-36863