A Generic Environment-Resistant Packaging Technology for MEMS

Lee, S.-H.; Lee, S.W.; Najafi, K.

doi:10.1109/sensor.2007.4300136

Cited by 20 publications

(16 citation statements)

References 4 publications

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“…Moreover, failure may arise from the large coefficient of thermal expansion (CTE) mismatch between the metal and silicon. On the other hand, for non-RF MEMS applications [9][10][11], single crystal silicon (SCS) is also employed to act as the through-wafer vias. These SCS vias are directly patterned on the low-resistivity silicon substrate by BOSCH DRIE (deep reactive ion etching) technology.…”

Section: Introductionmentioning

confidence: 99%

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Implementation of silicon-on-glass MEMS devices with embedded through-wafer silicon vias using the glass reflow process for wafer-level packaging and 3D chip integration

Lin

Hsu

Yang

et al. 2008

J. Micromech. Microeng.

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This study presents a novel system architecture to implement silicon-on-glass (SOG) MEMS devices on Si-glass compound substrate with embedded silicon vias. Thus, the 3D integration of MEMS devices can be accomplished by means of through-wafer silicon vias. The silicon vias connecting to the pads of devices are embedded inside the Pyrex glass. Parasitic capacitance for both vias and microstructures is decreased and mismatch of coefficient of thermal expansion (CTE) is reduced. In applications, the glass reflow process together with the SOG micromachining processes were employed to implement the presented concept. Successful driving of the resonator through the silicon vias is demonstrated. The wafer-level hermetic packaging can be further achieved by anodic bonding of a Pyrex7740 wafer. Hermeticity of the packaged device performed by helium leak test satisfied MIL-STD-883E. The packaged SOG device is SMT (surface mount technology) compatible and ready for 3D microsystem integration.

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Section: Introductionmentioning

confidence: 99%

“…Hence, high-aspect-ratio vias and small via pitch can be achieved. The electrical insulation of these SCS vias is easily provided by air [9] and dielectric materials [10,11] during the fabrication processes. The glass flow process (GFP) technology has been exploited in [12] to mold the glass using the silicon substrate.…”

Section: Introductionmentioning

confidence: 99%

Implementation of silicon-on-glass MEMS devices with embedded through-wafer silicon vias using the glass reflow process for wafer-level packaging and 3D chip integration

Lin

Hsu

Yang

et al. 2008

J. Micromech. Microeng.

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“…While improved sensitivity in accelerometers due to counteracting spring stiffness is an obvious use, 47 the prospect of vibration isolation of MEMS sensors in general has great potential. 48,49 Fig . 11 Load deflection curves obtained for the Si/SiO2 membrane, and the Si/SiO2 membrane with a 500 Å Ti/3000 Å gold metal layer deposited on the membrane.…”

Section: Load Deflection Testingmentioning

confidence: 99%

Using Micro-Raman Spectroscopy to Assess MEMS Si/SiO2 Membranes Exhibiting Negative Spring Constant Behavior

Starman

Coutu

2012

Exp Mech

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We introduce a novel micro-mechanical structure that exhibits two regions of stable linear positive and negative stiffness. Springs, cantilevers, beams and any other geometry that display an increasing return force that is proportional to the displacement can be considered to have a "Hookean" positive spring constant, or stiffness. Less well known is the opposite characteristic of a reducing return force for a given deflection, or negative stiffness. Unfortunately many simple negative stiffness structures exhibit unstable buckling and require additional moving components during deflection to avoid deforming out of its useful shape. In Micro-Electro-Mechanical Systems (MEMS) devices, buckling caused by stress at the interface of silicon and thermally grown SiO2 causes tensile and compressive forces that will warp structures if the silicon layer is thin enough. The 1 mm 2 membrane structures presented here utilizes this effect but overcome this limitation and empirically demonstrates linearity in both regions. The Si/SiO2 membranes presented deflect ~17 μm from their pre-released position. The load deflection curves produced exhibit positive linear stiffness with an inflection point holding nearly constant with a slight negative stiffness. Depositing a 0.05 μm titanium and 0.3 μm layer of gold on top of the Si/SiO2 membrane reduces the initial deflection to ~13.5 μm. However, the load deflection curve produced illustrates both a linear positive and negative spring constant with a fairly sharp inflection point. These results are potentially useful to selectively tune the spring constant of mechanical structures used in MEMS. The structures presented are manufactured using typical micromachining techniques and can be fabricated in-situ with other MEMS devices.

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“…Therefore, the packaging stress and the changes in the packaging stress should be suppressed. To these ends, conventional approaches employ mechanical or thermal isolators [6,7,8,9,10,11], low-stress adhesives [12,13], and calibration [14,15,16]. An isolator with a compliant beam element can decouple a structure from packaging stress.…”

Section: Introductionmentioning

confidence: 99%

Die-Attach Structure of Silicon-on-Glass MEMS Devices Considering Asymmetric Packaging Stress and Thermal Stress

Park

Jung

et al. 2019

Sensors

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Die attach is a typical process that induces thermal stress in the fabrication of microelectromechanical system (MEMS) devices. One solution to this problem is attaching a portion of the die to the package. In such partial die bonding, the lack of control over the spreading of the adhesive can cause non-uniform attachment. In this case, asymmetric packaging stress could be generated and transferred to the die. The performance of MEMS devices, which employ the differential outputs of the sensing elements, is directly affected by the asymmetric packaging stress. In this paper, we proposed a die-attach structure with a pillar to reduce the asymmetric packaging stress and the changes in packaging stress due to changes in the device temperature. To verify the proposed structure, we fabricated four types of differential resonant accelerometers (DRA) with the silicon-on-glass process. We confirmed experimentally that the pillar can control the spreading of the adhesive and that the asymmetric packaging stress is considerably reduced. The simulation and experimental results indicated that the DRAs manufactured using glass-on-silicon wafers as handle substrates instead of conventional glass wafers have a structure that compensates for the thermal stress.

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A Generic Environment-Resistant Packaging Technology for MEMS

Cited by 20 publications

References 4 publications

Implementation of silicon-on-glass MEMS devices with embedded through-wafer silicon vias using the glass reflow process for wafer-level packaging and 3D chip integration

Implementation of silicon-on-glass MEMS devices with embedded through-wafer silicon vias using the glass reflow process for wafer-level packaging and 3D chip integration

Using Micro-Raman Spectroscopy to Assess MEMS Si/SiO2 Membranes Exhibiting Negative Spring Constant Behavior

Die-Attach Structure of Silicon-on-Glass MEMS Devices Considering Asymmetric Packaging Stress and Thermal Stress

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