Chemical flip-chip bonding method for fabricating 10-μm-pad-pitch interconnect

Yasuhiro Yamaji*, Tokihiko Yokoshima, Katsuya Kikuchi, Hiroshi Nakagawa, Masahiro Aoyagi

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


A flip-chip bonding method has been developed for fabricating ultrafine-pitch pad-to-pad interconnects. The method utilizes the preferential growth of Ni-B bridge layers on resin walls in a microscale cavity structure fabricated in the underfill resin between copper pads facing each other under some conditions of electroless Ni-B plating. In this method, the interconnect can be fabricated without loading and/or heating. By controlling the growth of the bridge layer on the resin walls in the microscale cavity under optimized plating conditions, the feasibility of ultrafine-pitch flip-chip bonding with a 10-μm pad pitch is experimentally demonstrated at a temperature of 60°C.

Original languageEnglish
Pages (from-to)732-737
Number of pages6
Journalieice electronics express
Issue number18
Publication statusPublished - 2008 Sept 25
Externally publishedYes


  • Electroless plating
  • Fine pitch
  • Flip chip
  • Interconnect
  • Ni-B

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Electrical and Electronic Engineering


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