A flip–chip encapsulation method for packaging of MEMS actuators using surface micromachined polysilicon caps for BioMEMS applications

Panchawagh, Hrishikesh V.; Faheem, Faheem F.; Herrmann, Cari F.; Serrell, David B.; Finch, Dudley S.; Mahajan, Roop L.

doi:10.1016/j.sna.2006.05.013

Cited by 15 publications

(9 citation statements)

References 28 publications

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“…Okandan and Galambos [18] successfully integrated an electrostatically actuated MEMS device into a microfluidic system by separating the device in the channel from the actuator outside the channel with an oil/water interface. Panchawagh et al [19] demonstrated a similar packaging solution to seal MEMS actuators from the liquid environment, using flip-chip encapsulation with surface micromachined polysilicon caps and a hydrophobic coating. These approaches are only useful at low operating pressures and may not be reliable in practice.…”

mentioning

confidence: 99%

A Model for Electrostatic Actuation in Conducting Liquids

Panchawagh

Sounart

Mahajan

2009

J. Microelectromech. Syst.

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This paper presents a generalized model that describes the behavior of micromachined electrostatic actuators in conducting liquids and provides a guideline for designing electrostatic actuators to operate in aqueous electrolytes such as biological media. The model predicts static actuator displacement as a function of device parameters and applied frequency and potential for the typical case of negligible double-layer impedance and dynamic response. Model results are compared to the experimentally measured displacement of electrostatic comb-drive and parallelplate actuators and exhibit good qualitative agreement with experimental observations. The model is applied to show that the pull-in instability of a parallel-plate actuator is frequency dependent near the critical frequency for actuation and can be eliminated for any actuator design by tuning the applied frequency. In addition, the model is applied to establish a frequency-dependent theoretical upper bound on the voltage that can be applied across passivated electrodes without electrolysis.[2008-0307]

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mentioning

confidence: 99%

A Model for Electrostatic Actuation in Conducting Liquids

Panchawagh

Sounart

Mahajan

2009

J. Microelectromech. Syst.

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“…Unlike the previously reported flip-chip packaging designs by Erismis et al [25], Panchawagh et al [14], and Dy and Ho [27], the flip-chip packaging approach introduced in this paper contains the following distinct novelties that can be summarized as follows.…”

Section: Discussionmentioning

confidence: 99%

“…Since wire bonding is used, the overall package size is significantly larger than the die size. Panchawagh et al [14] introduced a flip-chip encapsulation method for the packaging of MEMS actuators by using surface-micromachined polysil-icon caps in combination with wire bonding. Faheem et al reported a nonhermetic packaging technique for RF MEMS as an alternative way to reduce MEMS packaging costs [15].…”

Section: Introductionmentioning

confidence: 99%

Packaging and Non-Hermetic Encapsulation Technology for Flip Chip on Implantable MEMS Devices

Sutanto

Anand

Sridharan

et al. 2012

J. Microelectromech. Syst.

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We report here a successful demonstration of a flip-chip packaging approach for a microelectromechanical systems (MEMS) device with in-plane movable microelectrodes implanted in a rodent brain. The flip-chip processes were carried out using a custom-made apparatus that was capable of the following: 1) creating Ag epoxy microbumps for first-level interconnect; 2) aligning the die and the glass substrate; and 3) creating non-hermetic encapsulation (NHE). The completed flip-chip package had an assembled weight of only 0.5 g significantly less than the previously designed wire-bonded package of 4.5 g. The resistance of the Ag bumps was found to be negligible. The MEMS micro-electrodes were successfully tested for its mechanical movement with microactuators generating forces of 450 μN with a displacement resolution of 8.8 μm/step. An NHE on the front edge of the package was created by patterns of hydrophobic silicone microstructures to prevent contamination from cerebrospinal fluid while simultaneously allowing the microelectrodes to move in and out of the package boundary. The breakdown pressure of the NHE was found to be 80 cm of water, which is significantly (4.5–11 times) larger than normal human intracranial pressures. Bench top tests and in vivo tests of the MEMS flip-chip packages for up to 75 days showed reliable NHE for potential long-term implantation.

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“…Second, electrolysis and polarization can hinder the device operation. Although there are approaches in the literature to avoid electrolysis and polarization by applying high frequency signals (Sounart et al 2005), these methods do not provide a solution for the former challenges (Panchawagh et al 2007).…”

Section: Introductionmentioning

confidence: 99%

“…Recently, an interesting encapsulation method is introduced by researchers including the authors of this paper which utilizes closely placed hydrophobic surfaces (Dy and Ho 2009;Erismis et al 2009;Panchawagh et al 2007). The actuator is surrounded by a wall structure completely but a clearance which allows the shuttle to extend off the edge of the device.…”

Section: Introductionmentioning

confidence: 99%

A water-tight packaging of MEMS electrostatic actuators for biomedical applications

et al. 2010

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This paper presents a flip-chip based packaging technique for encapsulating MEMS electrostatic actuators for biomedical applications. High-performance electrostatic inchworm actuators are used to demonstrate the packaging technique. A wall structure is put around the actuator surrounding it completely but leaving a small clearance where the actuator shuttle can extend off the edge of the chip. A cap chip is fabricated separately, and flip-chipped onto the actuator. Au-Au thermal bonding technique is used to fix the cap. Finally, rendering the surfaces of the clearance hydrophobic prevents the water ingress when the actuator operates in water.

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A flip–chip encapsulation method for packaging of MEMS actuators using surface micromachined polysilicon caps for BioMEMS applications

Cited by 15 publications

References 28 publications

A Model for Electrostatic Actuation in Conducting Liquids

A Model for Electrostatic Actuation in Conducting Liquids

Packaging and Non-Hermetic Encapsulation Technology for Flip Chip on Implantable MEMS Devices

A water-tight packaging of MEMS electrostatic actuators for biomedical applications

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