Improvement of crystallographic quality of electroplated copper thin-film interconnections for through-silicon vias

Ken Suzuki, Naokazu Murata, Naoki Saito, Ryosuke Furuya, Osamu Asai, Hideo Miura

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)

Abstract

The relationship between the electrical properties and crystallographic quality (crystallinity) of electroplated copper thin-film interconnections was investigated. The crystallinity of the grains and grain boundaries of the interconnections was evaluated on the basis of the image quality (IQ) value obtained by electron back-scatter diffraction (EBSD) analysis. The electrical properties of the interconnections vary markedly depending on their crystallinity. The crystallinity also changed markedly as functions of electroplating conditions and the annealing temperature after electroplating. Although the electro migration (EM) resistance of the annealed interconnection was improved, stress-induced migration (SM) was activated by a high residual stress after annealing. To improve electrical reliability without heat treatment after electroplating, the effects of the seed layer under the interconnections on the crystallinity were investigated. As a result, the crystallinity was improved by changing the seed layer from Cu to Ru. In addition, the decrease in current density during electroplating also improved the crystallinity. Therefore, both introducing the Ru seed layer and decreasing the current density during electroplating are effective for developing highly reliable copper interconnections.

Original languageEnglish
Article number04CB01
JournalJapanese journal of applied physics
Volume52
Issue number4 PART 2
DOIs
Publication statusPublished - 2013 Apr

ASJC Scopus subject areas

  • Engineering(all)
  • Physics and Astronomy(all)

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