Room-temperature cu microjoining with ultrasonic bonding of cone-shaped bump

Lijing Qiu, Akihiro Ikeda, Kazuhiro Noda, Seiya Nakai, Tanemasa Asano

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31 Citations (Scopus)


Room-temperature Cu-Cu bonding was realized by applying ultrasonic vibration together with compression force to the bonding of a cone-shaped bump. The size of the bump was about 10 μm. The connection pitch was 20 m. Mechanical characterization showed that the bonding strength increases with vibration amplitude and depends on the thickness of the counter electrode made of Cu. The thickness dependence of the bonding strength was found to be caused by an increase in the surface roughness of the counter electrode. It was shown that the bonding strength meets the requirement from application to products. Electrical characterization using a daisy-chain connection test demonstrated that more than 10,000 pins on a chip can be connected with a sufficiently low resistance.

Original languageEnglish
Article number04CB10
JournalJapanese journal of applied physics
Issue number4 PART 2
Publication statusPublished - Apr 2013

All Science Journal Classification (ASJC) codes

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


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