Investigation of the hermeticity of BCB-sealed cavities for housing (RF-)MEMS devices

Jourdain, Anne; Moor, Piet De; Pamidighantam, Sayanu; Tilmans, H.A.C.

doi:10.1109/memsys.2002.984361

Cited by 76 publications

(34 citation statements)

References 8 publications

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“…Range of leak rates that can be measured by the helium leak test [3]. It should be noted that any further testing using a gross leak test, which can only measure leak rates of 10 À4 atm-cm 3 /s and higher [7], will not be able to detect these False Pass packages.…”

Section: Test Condition Amentioning

confidence: 99%

On the applicability of MIL-Spec-based helium fine leak test to packages with sub-micro liter cavity volumes

Goswami

Han

2008

Microelectronics Reliability

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Section: Test Condition Amentioning

confidence: 99%

On the applicability of MIL-Spec-based helium fine leak test to packages with sub-micro liter cavity volumes

Goswami

Han

2008

Microelectronics Reliability

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“…That is, pressure inside the cavity increased during the storage test due to leakage or outgassing. However, we could not measure the leak rate of the gyroscope chip with a helium leak detector since the cavity volume of 7·10 À4 cm 3 in the gyroscope chip could be too small to be used with a helium leak detector even though the minimum detectable leak rate of the tester is 3·10 À11 atm cm 3 s À1 (Nese et al 1996;Jourdain et al 2002). Therefore, we could not figure out whether the leakage was increased during the storage test.…”

Section: Vacuum Packagingmentioning

confidence: 99%

Reliability of MEMS packaging: vacuum maintenance and packaging induced stress

Choa

2005

Microsyst Technol

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In this study, the dominant reliability issues of MEMS packaging that include vacuum maintenance and packaging induced stress, are discussed, and design considerations to improve the reliability are presented. The MEMS vibratory gyroscope sensor is fabricated with anodically bonded wafer level vacuum packaging followed by die-bonding and wire-bonding processes. The epoxy-molding compound (EMC) is applied to encapsulate the gyroscope sensor. Several methods to improve reliability of the vacuum packaging are suggested based on extensive work. The two major failure mechanisms of anodic vacuum packaging, namely leakage and outgassing are investigated. Leakage is effectively reduced by optimization of the bonding process. Outgassing inside the cavity can be minimized by application of Ti coating. Packaging induced stress is mainly caused by thermal expansion mismatch among the materials used to fabricate the package. During anodic bonding, thermo-mechanical stress is generated to the bonded wafer, which increases with temperature. The EMC encapsulation also produces package-induced stress. In order to increase robustness of the structure against deformation, a ''crab-leg'' type spring is replaced with a semi-folded spring. The results show that the frequency shift is greatly reduced after applying the semifolded spring.

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“…The cavity of the device is sealed with decompression inertial nitrogen gas. The temperature is higher than that in the case of Bstage epoxy [2] or benzocyclobutene (BCB) [3] as sealing materials. However, no critical bowing and deflection of the actuator is confirmed after packaging, because the actuator is made of single crystal silicon utilizing an active layer of an SOI wafer, which has less residual stress compared with deposited thin film actuators.…”

Section: Transmission Linesmentioning

confidence: 99%

“…Furthermore, the packaging process provides the damping and shock protection for the actuators, in that packaging may be performed at a controlled pressure. Recently various techniques of wafer level packaging for RF MEMS devices were proposed [2][3]. One of the packages is considered to get smaller parasitic parameters and interference for high frequency [2].…”

Section: Introductionmentioning

confidence: 99%

RF MEMS Switch with Wafer Level Package Utilizing Frit Glass Bonding

Fujii

Kimura

Satoh

et al. 2002

32nd European Microwave Conference, 2002

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This paper reports experimental results of RF characteristics up to 20 GHz of a RF MEMS switch applied with wafer level packaging. A glass wafer is used as a package substrate on which frit glass is printed as material to seal the MEMS devices. The package wafer is bonded to a device wafer, which consists of actuators and base substrates .The actuators are made of single crystal silicon that has less residual stress. The base substrate has through holes formed by sand blast. The switch achieves a low insertion loss of 1.3 dB and a high isolation of 19 dB up to 20 GHz, and can be mounted on to a circuit board with bumps, like flip chip. The wafer level packaging with low cost and high reliability will transfer RF MEMS devices, which has superior high frequency characteristics even in quasi-millimeter wave band, to the practical use.

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Investigation of the hermeticity of BCB-sealed cavities for housing (RF-)MEMS devices

Cited by 76 publications

References 8 publications

On the applicability of MIL-Spec-based helium fine leak test to packages with sub-micro liter cavity volumes

On the applicability of MIL-Spec-based helium fine leak test to packages with sub-micro liter cavity volumes

Reliability of MEMS packaging: vacuum maintenance and packaging induced stress

RF MEMS Switch with Wafer Level Package Utilizing Frit Glass Bonding

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