Particle removal without causing damage to MEMS structure

Hideki Hirano, Mahmoud Rasly, Neelam Kaushik, Masayoshi Esashi, Shuji Tanaka

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)


Particulate contamination on a wafer is the most crucial problem for wafer bonding, which is one of key process technologies for MEMS (Micro Electro Mechanical Systems). To address the problem, physical assists such as megasonic agitation is generally employed, but acoustic agitation often causes damage to fragile MEMS structures. In this study, several cleaning methods were compared in terms of both particle removal efficiency (PRE) and damage to the fragile MEMS structures. Conventional immersion type cleaning or ultrasonic cleaning cannot remove small particles efficiently, while atomized water jet spray (2-fluid jet spray) cleaning with pressurized nitrogen gas can effectively remove particles without damage to cantilever structures in a short time. Megasonic cleaning with de-ionized water can remove the particles, but it damages the cantilever structures at a same time. In contrast, megasonic cleaning with surfactant dissolved water or diluted ammonia/H2O 2 water can effectively remove particles even at a low physical energy, which causes no damage to the structures.

Original languageEnglish
Pages (from-to)157-163+5
JournalIEEJ Transactions on Sensors and Micromachines
Issue number5
Publication statusPublished - 2013 May 8


  • 2-fluid jet spray cleaning
  • Megasonic cleaning
  • Particulate contamination
  • Structural damage
  • Ultrasonic cleaning
  • Zeta-potential

ASJC Scopus subject areas

  • Mechanical Engineering
  • Electrical and Electronic Engineering


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