Wafer-level hermetic thermo-compression bonding using electroplated gold sealing frame planarized by fly-cutting

Muhammad Salman Al Farisi, Hideki Hirano, Jörg Frömel, Shuji Tanaka

Research output: Contribution to journalArticlepeer-review

43 Citations (Scopus)


In this paper, a novel wafer-level hermetic packaging technology for heterogeneous device integration is presented. Hermetic sealing is achieved by low-temperature thermo-compression bonding using electroplated Au micro-sealing frame planarized by single-point diamond fly-cutting. The proposed technology has significant advantages compared to other established processes in terms of integration of micro-structured wafer, vacuum encapsulation and electrical interconnection, which can be achieved at the same time. Furthermore, the technology is also achievable for a bonding frame width as narrow as 30 μm, giving it an advantage from a geometry perspective, and bonding temperatures as low as 300 °C, making it advantageous for temperature-sensitive devices. Outgassing in vacuum sealed cavities is studied and a cavity pressure below 500 Pa is achieved by introducing annealing steps prior to bonding. The pressure of the sealed cavity is measured by zero-balance method utilizing diaphragm-structured bonding test devices. The leak rate into the packages is determined by long-term sealed cavity pressure measurement for 1500 h to be less than Pa m3s-1. In addition, the bonding shear strength is also evaluated to be higher than 100 MPa.

Original languageEnglish
Article number015029
JournalJournal of Micromechanics and Microengineering
Issue number1
Publication statusPublished - 2017 Jan


  • Au-Au thermo-compression bonding
  • hetero-integration
  • single-point diamond fly-cutting
  • wafer-level hermetic sealing
  • zero-balance method

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Mechanics of Materials
  • Mechanical Engineering
  • Electrical and Electronic Engineering


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