Study of Vacuum-Assisted Spin Coating of Polymer Liner for High-Aspect-Ratio Through-Silicon-Via Applications

Yangyang Yan, Yingtao Ding, Takafumi Fukushima, Kang Wook Lee, Mitsumasa Koyanagi

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)


This paper provides a new approach for the formation of polymer liner for low-$k$ high-aspect-ratio through-silicon-vias involved in via-last backside-via 3-D integration applications. The approach mentioned, referred to as vacuum-assisted spin coating technique in this paper, is formed by combining a conventional spin coating technique and a vacuum treatment. Silicon blind vias with a diameter of 6~ μ m} and an aspect ratio of ∼ 8 were conformably coated on their sidewall with polyimide liner with the minimum step coverage ∼ 30 % by this approach. Impacts of via geometric parameters and wafer sizes on step coverage were investigated. Electrical characteristics were evaluated with a trench capacitor structure of which the insulator layer was formed by the vacuum-assisted spin coating technique. The minimum capacitance density of 5.3 nF/cm2 and the leakage current density of ∼ 3 nA/cm2 at a biased voltage of 5 V were obtained. The proposed vacuum-assisted spin coating technique is a simple, feasible, and cost-effective approach for 3-D integration applications.

Original languageEnglish
Article number7397981
Pages (from-to)501-509
Number of pages9
JournalIEEE Transactions on Components, Packaging and Manufacturing Technology
Issue number4
Publication statusPublished - 2016 Apr


  • 3-D integration
  • backside-via integration
  • polymer liner
  • through-silicon-vias (TSVs)
  • vacuum-assisted spin coating
  • via-last.


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