Microsystem Technologies

, Volume 25, Issue 1, pp 245–255 | Cite as

A micro vertically-allocated SU-8 check valve and its characteristics

  • Zebing Mao
  • Kazuhiro Yoshida
  • Joon-wan KimEmail author
Technical Paper


This paper proposes and develops a novel fabrication method to realize a micro vertically-allocated SU-8 check valve. The ordinary vertically-allocated SU-8 check valve formed by the photolithography has a limited overlap between an SU-8 cantilever and its valve seat, resulting in the low diodicity (i.e. the ratio of the forward flow to reverse flow rates). This overlap prevents the leakage through a bottom gap (a gap between a substrate and the SU-8 cantilever) and a top gap (a gap between a cover plate and the SU-8 cantilever) in the backward flow. These gaps, which are necessary for the movement of the SU-8 cantilever in the forward flow, must cause the leakage of check valves in the backward flow. To reduce the leakage and improve the diodicity, we propose to fabricate a novel fully-overlapped valve seat composed of channel walls, a bottom block, and a top block. To keep the advantages on the batch process of vertically-allocated SU-8 check valves, these blocks are desirable to be fabricated by the multi-layer process. We propose a multi-layer process for the bottom block and a novel beam forming process (a dose-controlled UV exposure) for the top block. In this paper, we design two types of check valves: (a) the ordinary partially-overlapped check valve; and (b) the proposed fully-overlapped check valve, to compare their diodicity. By investigating their flow rate characteristics experimentally, we conclude that the fully-overlapped check valve can reduce the leakage of 53.6% compared with the partially-overlapped check valve and increase the diodicity from 1.7 to 3.5 (about 2 times) at the supplied pressure of 18 kPa. We also demonstrate that the novel check valve exhibits higher performance and also show that our fully-overlapped check valve can be potentially applied to various microfluidics.



  1. Agirregabiria M, Blanco F, Berganzo J, Arroyo M, Fullaondo A, Mayora K, Ruano-Lopez J (2005) Fabrication of SU-8 multilayer microstructures based on successive CMOS compatible adhesive bonding and releasing steps. Lab Chip 5:545–552Google Scholar
  2. Al-Faqheri W, Ibrahim F, Thio THG, Aeinehvand MM, Arof H, Madou M (2015) Development of novel passive check valves for the microfluidic CD platform. Sens Actuators A 222:245–254Google Scholar
  3. Auroux P-A, Iossifidis D, Reyes DR, Manz A (2002) Micro total analysis systems. 2. Analytical standard operations and applications. Anal Chem 74:2637–2652Google Scholar
  4. Ball C, Renzi R, Priye A, Meagher R (2016) A simple check valve for microfluidic point of care diagnostics. Lab Chip 16:4436–4444Google Scholar
  5. Blanco F et al (2004) Novel three-dimensional embedded SU-8 microchannels fabricated using a low temperature full wafer adhesive bonding. J Micromech Microeng 14:1047Google Scholar
  6. Cheng C-H, Tseng Y-P (2013) Characteristic studies of the piezoelectrically actuated micropump with check valve. Microsyst Technol 19:1707–1715Google Scholar
  7. Chuang Y-J, Tseng F-G, Cheng J-H, Lin W-K (2003) A novel fabrication method of embedded micro-channels by using SU-8 thick-film photoresists. Sens Actuators A 103:64–69Google Scholar
  8. Chung C, Allen M (2004) Uncrosslinked SU-8 as a sacrificial material. J Micromech Microeng 15:N1Google Scholar
  9. Ezkerra A, Fernandez L, Mayora K, Ruano-Lopez J (2007) Fabrication of SU-8 free-standing structures embedded in microchannels for microfluidic control. J Micromech Microeng 17:2264Google Scholar
  10. Ezkerra A, Fernández LJ, Mayora K, Ruano-López JM (2011) SU8 diaphragm micropump with monolithically integrated cantilever check valves. Lab Chip 11:3320–3325Google Scholar
  11. Fang Y, Tan X (2010) A novel diaphragm micropump actuated by conjugated polymer petals: fabrication, modeling, and experimental results. Sens Actuators A 158:121–131Google Scholar
  12. Fu C, Rummler Z, Schomburg W (2003) Magnetically driven micro ball valves fabricated by multilayer adhesive film bonding. J Micromech Microeng 13:S96Google Scholar
  13. Gracias A, Feng X, Xu B, Castracane J (2006) Novel microfabrication approach of embedded SU8™ fluidic networks for cell transport on chips. J Micro Nanolithogr MEMS MOEMS 5:021102–021107Google Scholar
  14. Guerin L, Bossel M, Demierre M, Calmes S, Renaud P (1997) Simple and low cost fabrication of embedded micro-channels by using a new thick-film photoplastic. In: International conference on solid state sensors and actuators, 1997. TRANSDUCERS '97 Chicago. pp 1419–1422Google Scholar
  15. Hasselbrink EF, Shepodd TJ, Rehm JE (2002) High-pressure microfluidic control in lab-on-a-chip devices using mobile polymer monoliths. Anal Chem 74:4913–4918Google Scholar
  16. Izzo I, Accoto D, Menciassi A, Schmitt L, Dario P (2007) Modeling and experimental validation of a piezoelectric micropump with novel no-moving-part valves. Sens Actuators A 133:128–140Google Scholar
  17. Kajiwara S (2014) Effect of the check ball and inlet position on hydraulic L-shaped check ball behavior. J Fluids Struct 48:497–506Google Scholar
  18. Kim D, Beebe DJ (2007) A bi-polymer micro one-way valve. Sens Actuators A 136:426–433Google Scholar
  19. Kim J, Baek J, Lee K, Park Y, Sun K, Lee T, Lee S (2006) Photopolymerized check valve and its integration into a pneumatic pumping system for biocompatible sample delivery. Lab Chip 6:1091–1094Google Scholar
  20. Laser DJ, Santiago JG (2004) A review of micropumps. J Micromech Microeng 14:R35Google Scholar
  21. Ling Z, Liu C, Lian K (2009) Design and fabrication of SU-8 micro optic fiber holder with cantilever-type elastic microclips. Microsyst Technol 15:429–435Google Scholar
  22. Lorenz H, Despont M, Fahrni N, LaBianca N, Renaud P, Vettiger P (1997) SU-8: a low-cost negative resist for MEMS. J Micromech Microeng 7:121Google Scholar
  23. Low L-M, Seetharaman S, He K-Q, Madou MJ (2000) Microactuators toward microvalves for responsive controlled drug delivery. Sens Actuators B Chem 67:149–160Google Scholar
  24. Manz A, Graber N, Widmer H (1990) Miniaturized total chemical analysis systems: a novel concept for chemical sensing. Sens Actuators B Chem 1:244–248Google Scholar
  25. Mao Z, Yoshida K, Kim J-W (2018) Study on the fabrication of a SU-8 cantilever vertically-allocated in a closed fluidic microchannel. Microsyst Technol 24(5):2473–2483Google Scholar
  26. Ni J, Huang F, Wang B, Li B, Lin Q (2010) A planar PDMS micropump using in-contact minimized-leakage check valves. J Micromech Microeng 20:095033Google Scholar
  27. Ni J, Wang B, Chang S, Lin Q (2014) An integrated planar magnetic micropump. Microelectron Eng 117:35–40Google Scholar
  28. Oh KW, Ahn CH (2006) A review of microvalves. J Micromech Microeng 16:R13Google Scholar
  29. Paudel BJ, Jamal T, Thompson SM, Walters DK (2014) Thermal effects on micro-sized tesla valves. ASME 2014 4th Joint US-European fluids engineering division summer meeting collocated with the ASME 2014 12th International Conference on nanochannels, microchannels, and minichannels. American Society of Mechanical Engineers, New York, pp V002T019A006–V002T019A006Google Scholar
  30. Rahbar M, Shannon L, Gray BL (2016) Design, fabrication and characterization of an arrayable all-polymer microfluidic valve employing highly magnetic rare-earth composite polymer. J Micromech Microeng 26:055012Google Scholar
  31. Reyes DR, Iossifidis D, Auroux P-A, Manz A (2002) Micro total analysis systems. 1. Introduction, theory, and technology. Anal Chem 74:2623–2636Google Scholar
  32. Schluter M, Kampmeyer U, Tahhan I, Lilienhof H-J (2002) A modular structured, planar micro pump with no moving part (NMP) valve for fluid handling in microanalysis systems. In: 2nd annual international IEEE-EMBS special topic conference on microtechnologies in medicine and biology. Proceedings (Cat. No.02EX578), pp 500–503Google Scholar
  33. Seidemann V, Bütefisch S, Büttgenbach S (2002) Fabrication and investigation of in-plane compliant SU8 structures for MEMS and their application to micro valves and micro grippers. Sens Actuators A 97:457–461Google Scholar
  34. Shih T-K, Chen C-F, Ho J-R, Chuang F-T (2006) Fabrication of PDMS (polydimethylsiloxane) microlens and diffuser using replica molding. Microelectron Eng 83:2499–2503Google Scholar
  35. Terry SC, Jerman JH, Angell JB (1979) A gas chromatographic air analyzer fabricated on a silicon wafer. IEEE Trans Electron Devices 26:1880–1886Google Scholar
  36. Wang B, Ni J, Litvin Y, Pfaff DW, Lin Q (2012) A microfluidic approach to pulsatile delivery of drugs for neurobiological studies. J Microelectromech Syst 21:53–61Google Scholar
  37. Yang B, Lin Q (2007) A planar compliance-based self-adaptive microfluidvariable resistor. J Microelectromech Syst 16:411–419Google Scholar
  38. Yang E-H, Lee C, Mueller J, George T (2004) Leak-tight piezoelectric microvalve for high-pressure gas micropropulsion. J Microelectromech Syst 13:799–807Google Scholar
  39. Yoshida K, Tanaka S, Hagihara Y, Tomonari S, Esashi M (2010) Normally closed electrostatic microvalve with pressure balance mechanism for portable fuel cell application. Sens Actuators A 157:290–298Google Scholar

Copyright information

© Springer-Verlag GmbH Germany, part of Springer Nature 2018

Authors and Affiliations

  1. 1.Department of Mechanical Engineering, School of EngineeringTokyo Institute of TechnologyYokohamaJapan
  2. 2.Laboratory for Future Interdisciplinary Research of Science and Technology (FIRST)Tokyo Institute of TechnologyYokohamaJapan

Personalised recommendations