Microsystem Technologies

, Volume 23, Issue 8, pp 3547–3558 | Cite as

Vacuum cavity encapsulation for response time shortening in flexible thermal flow sensor

  • Mitsuhiro ShikidaEmail author
  • Pilyoung Kim
  • Shunji Shibata
Technical Paper


A vacuum cavity encapsulation fabrication process for a thermal sensor based on a Cu on polyimide (COP) substrate was studied to shorten the response time, and it was applied to a flow sensor application. First, the sacrificial etching properties of a Cu layer for designing and forming a cavity under a heater for thermal isolation and an electrical feedthrough into the Cu layer were evaluated. The etching rates depended on the hole size of an etching mask pattern and the distance between two holes. Then, the relationship between the amount of parylene dimer and the sealing thickness in a lateral direction in the etching hole by its deposition was investigated to encapsulate the cavity under a vacuum condition. The thickness increased linearly with the amount of dimer, and the hole was successfully sealed by the parylene film under a vacuum condition. The vacuum cavity encapsulation was applied to the flexible thermal flow sensor to shorten the response time. The response time value was successfully shortened to three-fifths by applying the vacuum cavity encapsulation, and it did not change after 2 months.


Polyimide Thermal Sensor Hole Size Micro Electro Mechanical System Polyimide Film 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.



This research was supported by JSPS KAKENHI Grant No. 26286034, Japan.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2016

Authors and Affiliations

  1. 1.Department of Biomedical ScienceHiroshima City UniversityHiroshimaJapan
  2. 2.Department of Mechanical Science EngineeringNagoya UniversityNagoyaJapan
  3. 3.Department of Micro-Nano Systems EngineeringNagoya UniversityNagoyaJapan

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