: Gas transport mechanisms that characterize the hermetic behavior of MEMS packages are fundamentally different depending upon which sealing materials are used in the packages. In metallic seals, gas transport occurs through a few nanoscale leak channels (gas conduction) that are produced randomly during the solder reflow process, while gas transport in polymeric seals occurs through the bulk material (gas diffusion). In this review article, the techniques to measure true leak rates of MEMS packages with the two sealing materials are described and discussed: a Helium mass spectrometer based technique for metallic sealing and a gas diffusion based model for polymeric sealing.
References
[1]
Dohle, G.R.; Drabik, T.J.; Callahan, J.J.; Martin, K.P. Low temperature bonding of epitaxial lift off devices with AuSn. IEEE Trans. Compon. Packag. Manuf. Technol. Part B 1996, 19, 575–580.
[2]
Mitchell, J.; Lahiji, G.R.; Najafi, K. Encapsulation of Vacuum Sensors in a Wafer Level Package Using a Gold-Silicon Eutectic. Proceedings of the 13th International Conference on Solid-State Sensors, Actuators and Microsystems, (RANSDUCERS ’05), Seoul, Korea, 5–9 June 2005; 921, pp. 928–931.
[3]
Li, L.; Jiao, J.; Luo, L.; Wang, Y. Cu/Sn Isothermal Solidification Technology for Hermetic Packaging of MEMS. Proceedings of the 1st IEEE International Conference on Nano/Micro Engineered and Molecular Systems, (NEMS ’06), Zhuhai, China, 18–21 January 2006; pp. 1133–1137.
[4]
Sarvar, F.; Hutt, D.A.; Whalley, D.C. Application of Adhesives in MEMS and MOEMS Assembly: A Review. Proceedings of the 2nd International IEEE Conference on Polymers and Adhesives in Microelectronics and Photonics, (POLYTRONIC 2002), Zalaegerszeg, Hungary, 23–26 June 2002; pp. 22–28.
Jourdain, A.; De Moor, P.; Pamidighantam, S.; Tilmans, H.A.C. Investigation of the Hermeticity of BCB-Sealed Cavities for Housing (RF-)MEMS Devices. Proceedings of the Fifteenth IEEE International Conference on Micro Electro Mechanical Systems, Las Vegas, NV, USA, 20–24 January 2002; pp. 677–680.
[7]
Noh, H.; Kyoung-sik, M.; Cannon, A.; Hesketh, P.J.; Wong, C.P. Wafer Bonding Using Microwave Heating of Parylene for MEMS Packaging. Proceedings of the 54th Electronic Components and Technology Conference, Las Vegas, NV, USA, 1–4 June 2004; 921, pp. 924–930.
[8]
Hablanian, M. High-Vacuum Technology a Practical Guide; CRC Press Inc: Boca Raton, FL, USA, 1997; p. 493.
[9]
Knarr, O.M. Industrial Gaseous Leak Detection Manual; McGraw Hill: New York, NY, USA, 1998; p. 97.
[10]
Goswami, A.; Han, B.; Ham, S.J.; Jeong, B.G. Quantitative Characterization of True Leak Rate of Micro to Nanoliter Packages Using Helium Mass Spectrometer. IEEE Trans. Adv. Packag 2009, 32, 440–447.
[11]
Goswami, A.; Han, B. On ultra-fine leak detection of hermetic wafer level packages. IEEE Trans. Adv. Packag 2008, 31, 14–21.
[12]
Goswami, A.; Han, B. On the applicability of MIL-Spec-based helium fine leak test to packages with sub-micro liter cavity volumes. Microelectron. Reliab 2008, 48, 1815–1821.
[13]
Jang, C.; Cho, Y.-R.; Han, B. Ideal laminate theory for water transport analysis of metal-coated polymer films. Appl. Phys. Lett 2008, 93, 133307:1–133307:3.
[14]
Jang, C.; Goswami, A.; Han, B. Hermeticity evaluation of polymer-sealed MEMS packages by gas diffusion analysis. IEEE/ASME J. Microelectromechanical Syst 2009, 18, 577–587.
[15]
Jang, C.; Goswami, A.; Han, B.; Ham, S. In-situ measurement of gas diffusion properties of polymeric seals used in MEMS Packages by optical gas leak test. J. Micro Nanolithography MEMS MOEMS 2009, 8, doi:10.1117/1.3227904.
[16]
Jang, C.; Park, S.; Han, B.; Yoon, S. Advanced thermal-moisture analogy scheme for anisothermal moisture diffusion problem. J. Electron. Packag 2008, 130, 011004:1–011004:8.
[17]
Jang, C.; Youn, B.; Wang, P.F.; Han, B.; Ham, S.-J. Forward-stepwise regression analysis for fine leak batch testing of multiple MEMS package. Microelectron. Reliab 2010, 18, 577–587.
[18]
Dushman, S. Scientific Foundations of Vacuum Technique, 2nd ed ed.; John Wiley & Sons, Inc: New York, NY, USA, 1962; pp. 80–117.
[19]
Greenhouse, H. Hermeticity of Electronic Packages; Noyes Publications: Saddle River, NJ, USA, 2000; p. 20.
[20]
Knudsen, M. The law of the molecular flow and viscosity of gases moving through tubes. Ann. Phys 1909, 28, 75–130.
[21]
MIL-STD-883F Method 1014.12, Test Method Standard Microcircuits; US Department of Defense: Arlington, VA, USA, 2004.
[22]
Tao, Y.; Malshe, A.P. Theoretical investigation on hermeticity testing of MEMS packages based on MIL-STD-883E. Microelectron. Reliab 2005, 45, 559–566.
[23]
Dally, J.W.; Riley, W.F. Experimental Stress Analysis, 3rd ed ed.; McGraw-Hill: New York, NY, USA, 1991; pp. 616–619.
[24]
Wang, Z.; Cardenas-Garcia, J.F.; Han, B. Inverse method to determine elastic constants using a circular disk and moire interferometry. Exp. Mech 2005, 45, 27–34.
[25]
Elger, G.; Shiv, L.; Nikac, N.; Muller, F.; Liebe, R.; Grigat, M. Optical Leak Detection for Wafer Level Hermeticity Testing. Proceedings of the IEEE/CPMT/SEMI 29th International Electronics Manufacturing Technology Symposium, San Jose, CA, USA, 14–16 July 2004; pp. 326–331.
[26]
Goswami, A.; Han, B. Hermeticity Detection of Wafer Level MEMS Packages Using an Optical Technique. Proceedings of the 6th International Symposium on MEMS and Nanotechnology, Portland, OR, USA, 6–9 June 2005; pp. 47–53.
[27]
Post, D.; Han, B.; Ifju, P. High Sensitivity Moiré: Experimental Analysis for Mechanics and Materials; Springer-Verlag: New York, NY, USA, 1994.
[28]
Wang, Z. Development and Application of Computer-Aided Fringe AnalysisPh.D. Dissertation. University of Maryland, College Park, MD, USA, 2003.
[29]
Morimoto, Y.; Fujisawa, M. Fringe pattern analysis by a phase-shifting method using Fourier transform. Opt. Eng 1994, 33, 3709–3714.
