Reducing the Hygroscopic Swelling in MEMS Sensor using Different Mold Materials

Today, Hygroscopic swelling is one of the biggest challenging problem of Epoxy mold compound (EMC) in packaging with Microelectromechanical system (MEMS) devices. To overcome this hygroscopic swelling problem of EMC and guard the devices, MEMS devices are molded in this paper with different Mold Compound (MC) i.e. titanium and ceramic etc. during their interconnection with the board. Also, a comparatively performance analysis of this various mold compound with MEMS pressure sensor has been studied in this paper at 60% humidity, 140 mol/m<sup>3</sup> saturation concentration and 25 <sup>o</sup>C. It was observed that hygroscopic swelling does not take place in the titanium mold compound. But, titanium is very costly so we have to consider something cheaper material i.e. ceramic in this paper. The Hygroscopic swelling in Ceramic Mold Compound after 1 year is nearly 0.05mm which is very less than epoxy.

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Interfacing a Microelectromechanical System (MEMS) Sensor Array for Traumatic Brain Injury Detection with a Microcontroller

10.21236/ada569540 ◽

2012 ◽

Author(s):

Timothy C. Lee ◽

Luke J. Currano

Keyword(s):

Traumatic Brain Injury ◽

Brain Injury ◽

Sensor Array ◽

Microelectromechanical System ◽

Mems Sensor

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Colocalized Sensing and Intelligent Computing in Micro-Sensors

Sensors ◽

10.3390/s20216346 ◽

2020 ◽

Vol 20 (21) ◽

pp. 6346

Author(s):

Mohammad H Hasan ◽

Ali Al-Ramini ◽

Eihab Abdel-Rahman ◽

Roozbeh Jafari ◽

Fadi Alsaleem

Keyword(s):

Electrical Signal ◽

Virtual Node ◽

Noise Resistance ◽

Microelectromechanical System ◽

Analog To Digital ◽

Intelligent Computing ◽

Electrostatically Actuated ◽

Digital To Analog Converters ◽

Mems Sensor ◽

Mems Device

This work presents an approach to delay-based reservoir computing (RC) at the sensor level without input modulation. It employs a time-multiplexed bias to maintain transience while utilizing either an electrical signal or an environmental signal (such as acceleration) as an unmodulated input signal. The proposed approach enables RC carried out by sufficiently nonlinear sensory elements, as we demonstrate using a single electrostatically actuated microelectromechanical system (MEMS) device. The MEMS sensor can perform colocalized sensing and computing with fewer electronics than traditional RC elements at the RC input (such as analog-to-digital and digital-to-analog converters). The performance of the MEMS RC is evaluated experimentally using a simple classification task, in which the MEMS device differentiates between the profiles of two signal waveforms. The signal waveforms are chosen to be either electrical waveforms or acceleration waveforms. The classification accuracy of the presented MEMS RC scheme is found to be over 99%. Furthermore, the scheme is found to enable flexible virtual node probing rates, allowing for up to 4× slower probing rates, which relaxes the requirements on the system for reservoir signal sampling. Finally, our experiments show a noise-resistance capability for our MEMS RC scheme.

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

Sensors ◽

10.3390/s19183979 ◽

2019 ◽

Vol 19 (18) ◽

pp. 3979

Author(s):

Jun Eon An ◽

Usung Park ◽

Dong Geon Jung ◽

Chihyun Park ◽

Seong Ho Kong

Keyword(s):

Thermal Stress ◽

Silicon Wafers ◽

Experimental Results ◽

Mems Devices ◽

Microelectromechanical System ◽

Die Attach ◽

Lack Of Control ◽

Die Bonding ◽

Glass Process ◽

Typical Process

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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Fabrication of Mems Devices by Powder-Filling into DXRL-Formed Molds

MRS Proceedings ◽

10.1557/proc-546-195 ◽

1998 ◽

Vol 546 ◽

Author(s):

Terry J. Garino ◽

Todd Christenson ◽

Eugene Venturini

Keyword(s):

High Temperature ◽

Bulk Material ◽

The Other ◽

Ceramic Mold ◽

Magnetic Powder ◽

Mems Devices ◽

X Ray ◽

Energy Product ◽

Zn Ferrite ◽

Micro Actuators

AbstractWe have developed a variety of processes for fabricating components for micro devices based on deep x-ray lithography (DXRL). Although the techniques are applicable to many materials, we have demonstrated them using hard (Nd 2Fe14B) and soft (Ni-Zn ferrite) magnetic materials because of the importance of these materials in magnetic micro-actuators and other devices and because of the difficulty fabricating them by other means. The simplest technique involves pressing a mixture of magnetic powder and a binder into a DXRL-formed mold. In the second technique, powder is pressed into the mold and then sintered to densify. The other two processes involve pressing at high temperature either powder or a dense bulk material into a ceramic mold that was previously made using a DXRL mold. These techniques allow arbitrary 2-dimensional shapes to be made 10 to 1000 μm thick with in-plane dimensions as small as 50μm and dimensional tolerances in the micron range. Bonded isotropic Nd2Fe14B micro-magnets made by these processes had an energy product of 7 MGOe.

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Geometric Optimization of van der Pauw Structure Based MEMS Pressure Sensor

Volume 11: Micro and Nano Systems, Parts A and B ◽

10.1115/imece2007-42307 ◽

2007 ◽

Author(s):

Jesse Law ◽

Robert Cassel ◽

Ahsan Mian

Keyword(s):

Pressure Sensor ◽

Silicon Crystal ◽

Relative Size ◽

Orientation Angle ◽

Wheatstone Bridge ◽

Geometric Optimization ◽

Biaxial Stress ◽

Mems Devices ◽

Piezoresistive Sensor ◽

Van Der Pauw

This paper characterizes a piezoresistive sensor under variations of both size and orientation with respect to the silicon crystal lattice for its application to MEMS pressure sensing. The sensor to be studied is a four-terminal piezoresistive sensor commonly referred to as a van der Pauw (VDP) structure. In a recent study, our team has determined the relation between the biaxial stress state and the piezoresistive response of a VDP structure by combining the VDP resistance equations with the equations governing silicon piezoresistivity and has proposed a novel piezoresistive pressure sensor. It is observed that the sensitivity of the VDP sensor is over three times higher than the conventional filament type Wheatstone bridge resistor. With MEMS devices being used in applications which continually necessitate smaller size, characterizing the effect of relative size and misalignment on the sensitivity of the VDP sensor is important. It is determined that the performance of the sensor is strongly dependent only on the longitudinal position of the sensor on the diaphragm, and is relatively tolerant of other errors in the manufacturing process such as transverse position, sensor depth, and orientation angle.

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Performance analysis of MEMS sensor for the detection of cholera and diarrhea

Microsystem Technologies ◽

10.1007/s00542-018-3810-9 ◽

2018 ◽

Vol 24 (9) ◽

pp. 3705-3712 ◽

Cited By ~ 1

Author(s):

K. V. Vineetha ◽

K. Girija Sravani ◽

B. V. S. Sailaja ◽

P. Ashok Kumar ◽

Koushik Guha ◽

...

Keyword(s):

Performance Analysis ◽

Mems Sensor

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Simulation of Low Pressure MEMS Sensor for Biomedical Application

Journal of Nanotechnology in Engineering and Medicine ◽

10.1115/1.4004025 ◽

2011 ◽

Vol 2 (3) ◽

Cited By ~ 1

Author(s):

S. Sathyanarayanan ◽

A. Vimala Juliet

Keyword(s):

Pressure Sensor ◽

Microelectromechanical Systems ◽

Biomedical Application ◽

Applied Pressure ◽

Analysis Data ◽

Operating Pressure ◽

Capacitive Pressure Sensor ◽

Element Analysis ◽

Mems Sensor ◽

Relationship Of

Micromachining technology has greatly benefited from the success of developments in implantable biomedical microdevices. In this paper, microelectromechanical systems (MEMS) capacitive pressure sensor operating for biomedical applications in the range of 20–400 mm Hg was designed. Employing the microelectromechanical systems technology, high sensor sensitivities and resolutions have been achieved. Capacitive sensing uses the diaphragm deformation-induced capacitance change. The sensor composed of a rectangular polysilicon diaphragm that deflects due to pressure applied over it. Applied pressure deflects the 2 µm diaphragm changing the capacitance between the polysilicon diaphragm and gold flat electrode deposited on a glass Pyrex substrate. The MEMS capacitive pressure sensor achieves good linearity and large operating pressure range. The static and thermo electromechanical analysis were performed. The finite element analysis data results were generated. The capacitive response of the sensor performed as expected according to the relationship of the spacing of the plates.

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The Study on the Analytic Model and Design Software for IP of Piezoresistive Cantilever Beams

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.562-565.482 ◽

2013 ◽

Vol 562-565 ◽

pp. 482-485

Author(s):

Jian Long Zhu ◽

Wei Hua Li ◽

Zai Fa Zhou ◽

Qin Gan Huang

Keyword(s):

Output Voltage ◽

Voltage Sensitivity ◽

Analytic Model ◽

Cantilever Beams ◽

Mems Devices ◽

New Model ◽

Mems Sensor ◽

Piezoresistive Sensor ◽

Design Software

Piezoresistive sensor was one of the earliest silicon MEMS devices, which based on the theory of piezoresistive. In order to build the piezoresistive IP library for the MEMS foundry, we improved the structures of the piezoresistive based on the achievement of Liwei Lin1, and new analytic model and design software for square shape membrance has been developed. The ability to calculate sensitivity and linearity of MEMS piezoresistive sensor using the new model have been demonstrated. As results, output voltage, sensitivity and linearity characteristics of MEMS sensor are presented in this paper.

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Micromachining of mesoporous oxide films for microelectromechanical system structures

Journal of Materials Research ◽

10.1557/jmr.2002.0313 ◽

2002 ◽

Vol 17 (8) ◽

pp. 2121-2129 ◽

Cited By ~ 22

Author(s):

Jong-Ah Paik ◽

Shih-Kang Fan ◽

Chang-Jin Kim ◽

Ming C. Wu ◽

Bruce Dunn

Keyword(s):

Sacrificial Layer ◽

Oxide Films ◽

Average Diameter ◽

High Porosity ◽

Mems Devices ◽

Mesoporous Films ◽

Microelectromechanical System ◽

Mesoporous Oxide ◽

Structure Layer ◽

Mesoporous Oxides

The high porosity and uniform pore size of mesoporous oxide films offer unique opportunities for microelectromechanical system (MEMS) devices that require low density and low thermal conductivity. This paper provides the first report in which mesoporous films were adapted for MEMS applications. Mesoporous SiO2 and Al2O3 films were prepared by spin coating using block copolymers as the structure-directing agents. The resulting films were over 50% porous with uniform pores of 8-nm average diameter and an extremely smooth surface. The photopatterning and etching characteristics of the mesoporous films were investigated and processing protocols were established which enabled the films to serve as the sacrificial layer or the structure layer in MEMS devices. The unique mesoporous morphology leads to novel behavior including extremely high etching rates and the ability to etch underlying layers. Surface micromachining methods were used to fabricate three basic MEMS structures, microbridges, cantilevers, and membranes, from the mesoporous oxides.

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