Survivability of MEMS Accelerometer Under Sequential Thermal and High-G Mechanical Shock Environments

2015 ◽  
Author(s):  
Pradeep Lall ◽  
Amrit Abrol ◽  
Lee Simpson ◽  
Jessica Glover
Keyword(s):  
Failure Modes ◽  
Performance Enhancement ◽  
Research Work ◽  
Harsh Environments ◽  
Mechanical Shock ◽  
X Rays ◽  
Mems Devices ◽  
Mems Accelerometer ◽  
Capacitive Accelerometer ◽  
Mems Accelerometers

Reliability data on MEMS accelerometers operating in harsh environments is scarce. Micro-electro-mechanical systems (MEMS) are used in a variety of military and automotive applications for sensing acceleration, translation, rotation, pressure and sound. This research work focuses on dual axis MEMS accelerometer reliability in harsh environments. Structurally an accelerometer behaves like a damped mass on a spring. Commercially there are three types of accelerometers namely piezoelectric, piezoresistive and capacitive depending on the components that go into the fabrication of the MEMS device. Previously, majority of concentration was focused on an effective internal design, performance enhancement of CMOS-MEMS accelerometers and packaging techniques Cheng [2002], Qiao [2009], Lou [2005], and Weigold [2001]. Studies have also been conducted to obtain an enhanced inertial mass SOI MEMS process using a high sensitivity accelerometer Jianbing [2013], Chen [2005]. There have been prior test(s) conducted on MEMS accelerometers, Jiang [2004], Cao [2011], Chun-Sun [2009], Lou [2009], Tanner [2000] and Yang [2010] but the availability of data on reliability degradation of such devices in harsh environments Brown [2003] is almost little to none which thereby generates the importance of this work and also makes way for a whole new path involving the reliability assessment techniques for MEMS devices. Concentration of our work is primarily on the reliability of this accelerometer upon sequential exposure to harsh environment(s) and drop-shock. Reliability of accelerometers in high G environments is unknown. The effects of these pre-conditions along with the drop test condition has been studied and analyzed. In this piece of research work, a test vehicle with a MEMS accelerometer, ADXL278 dual axis capacitive accelerometer, has been tested under high/low temperature exposure followed by subjection to high-g and low-g shock loading environments. The test boards have been subjected to mechanical shocks using the method 2002.5, condition G, under the standard MIL-STD-883H test. The stress environment and the test condition used for this paper are 1500g and 70g respectively where 70g is the full scale range output of ADXL278 in the drop direction with pulse duration set to 0.5millisecond. The deterioration of the accelerometer output has been characterized using the techniques of Mahalanobis distance and Confidence intervals. Scanning Electron Microscopy (SEM) has been used to study the different failure modes inside of the accelerometer, which were potted and polished and later de-capped. Furthermore, the non-destructive evaluations of the MEMS accelerometer have been demonstrated through X-rays and micro-CT scans.

Mechanical Shock Reliability Analysis and Multiphysics Modeling of MEMS Accelerometers in Harsh Environments

2015 ◽  
Author(s):  
Pradeep Lall ◽  
Nakul Kothari ◽  
Jessica Glover
Keyword(s):  
Failure Modes ◽  
Complex Structure ◽  
Harsh Environments ◽  
Mechanical Shock ◽  
Mems Devices ◽  
Ambient Conditions ◽  
Physics Of Failure ◽  
Mems Sensor ◽  
Voltage Change ◽  
Mems Accelerometers

MEMS accelerometers have found applications in harsh environments with pressure, temperatures above ambient conditions, high g shock and vibrations. The complex structure of these MEMS devices has made it difficult to understand the failure modes and failure mechanisms of present day MEMS accelerometers. Little work has been done by the researchers in investigating the high g reliability of the MEMS accelerometers by continuous high g drops and quantifying the failure modes. There is little literature addressing the multiphysics finite element modelling of MEMS accelerometers subjected to high g shocks. In defense applications, where these devices are integrated with several other compactly assembled subsystems, lack of knowledge on the physics of failure for the MEMS sensor in harsh environment operation, can be detrimental to the success of the system on the whole. Being able to successfully model inside of an accelerometer, enables the user to better understand the change in parameters like time delay induced in response of successive drops, change in pulse width that indicate failure, reduction in sensed g levels. Some researchers have subjected various accelerometers to repeated drops at their maximum sensing g(not high g) level, and used optical microscopy to detect damaged sensing elements [Beliveau, 1999]. Few researchers have modeled the internal structure of the MEMS device, along with the device packaging under the stresses of operation [Fang 2004, Ghisi 2008, Xiong 2008]. In this paper, a multiphysics model of capacitive and the moving elements of the accelerometer has been developed to model the change in capacitance with respect to stroke and understand the correlation with g-levels, in addition to the transient dynamic response of the accelerometer under high-g shock. This has not been much explored in the past. The accelerometer studied in the paper is the ADXL193, and subjected to repeated drops of 3000g in each 3 axes as per 2002.4 of MIL-STD-883 without preconditioning. A characteristic graph of capacitance vs accelerometer stroke has been obtained from a series of electrostatic simulations and is then used to relate g levels, capacitance, stroke deflection and voltage change using electromechanical transducer elements. The drift in the performance characteristics of the accelerometer have been measured versus the number of shock events. In addition, an attempt has been made to investigate the failure mode in the accelerometer.

The Response of Electrostatic MEMS Structure under Mechanical Shock and Electrostatic Forces

2013 ◽  
Vol 427-429 ◽  
pp. 120-123
Author(s):  
Xiang Guang Li ◽  
Qin Wen Huang ◽  
Yun Hui Wang ◽  
Yu Bin Jia ◽  
Zhi Bin Wang
Keyword(s):  
Failure Modes ◽  
Electrostatic Force ◽  
Short Circuit ◽  
Superposition Method ◽  
Mechanical Shock ◽  
Mems Devices ◽  
Electrostatic Forces ◽  
Mode Superposition Method ◽  
Electrostatic Mems ◽  
Micro Cantilever

For MEMS devices actuated by electrostatic force, unexpected failure modes can be hardly predicted when the electrostatic force coupled with the shock. A response model is established when a micro cantilever subjected to electrostatic force and mechanical shock. First, based on the theory of transverse forced vibration in vibration mechanics, the equation of motion under shock and electrostatic fore is presented. Then the reduced order model is gained after simplifying by mode superposition method. The computing results indicate that: the shock amplitude and duration are the key factors to affect the reliability of the device; the shock load and electrostatic forces make the threshold voltage much lower than the anticipated value. The micro cantilever may collapse to the substrate even at a voltage far lower than the pull-in voltage. This early dynamic pull-in instability may cause some failures such as short circuit, adhesion or collision damage.

Design Specifications for Biaxial Navigation-Grade MEMS Accelerometers

2014 ◽  
Author(s):  
Xiaowei Shan ◽  
Ting Zou ◽  
James Richard Forbes ◽  
Jorge Angeles
Keyword(s):  
Frequency Ratio ◽  
Proof Mass ◽  
Mechanical Performance ◽  
Design Parameters ◽  
Mass Motion ◽  
Mems Devices ◽  
Mems Accelerometer ◽  
Potential Market ◽  
Mems Accelerometers ◽  
Commercial Landscape

The focus of this paper is the design of a biaxial MEMS accelerometer for navigation applications. First, a survey is conducted to outline the commercial landscape of navigation-grade and MEMS accelerometers. The survey shows a potential market for navigation-grade accelerometers at the MEMS scale. Based on the specifications for navigation applications, the design targets are derived for the proposed biaxial MEMS accelerometers, including the common concerns of natural frequency ratios and bandwidth, as well as the important parameters for MEMS devices, such as hinge width, proof-mass size and mobility range. In light of the design targets, the ideal frequency matrix of the biaxial accelerometer system is derived based on the concept of generalized spring, in connection with the design targets. The stiffness values required are estimated herein. For further structural optimization, the parametric entries of the frequency-ratio matrix act as the objectives to be maximized for the lowest off-axis sensitivity of the proposed accelerometer. A suitable architecture for MEMS biaxial accelerometers is proposed thereafter. This architecture not only provides high compliance and structural isotropy for the in-plane translation, but also allows for direct measurement of the proof-mass motion. The proposed architecture is then optimized for the highest frequency ratio between the non-sensitive and sensitive axes, with regard to the design parameters and constraints. The optimization results of the proposed accelerometer demonstrate navigation-grade mechanical performance.

scholarly journals Identification of Stator Winding Insulation Faults in Three-Phase Induction Motors Using MEMS Accelerometers

Proceedings ◽  
2019 ◽  
Vol 42 (1) ◽  
pp. 66
Author(s):  
Karl Schiewaldt ◽  
Guilherme Lucas ◽  
Marco Rocha ◽  
Claudio Fraga ◽  
Andre Andreoli
Keyword(s):  
Fault Diagnosis ◽  
Vibration Analysis ◽  
Induction Motors ◽  
Low Cost ◽  
Industrial Sector ◽  
Mems Devices ◽  
Mems Accelerometer ◽  
Three Phase ◽  
Special Cases ◽  
Mems Accelerometers

In recent years, the advancement of the microelectronics industry has allowed for a major expansion in the development of sensor-based equipment and applications, driven primarily by the cost reduction of micro-electro-mechanical systems (MEMS) devices. Currently, using this type of component, it is feasible to develop cost-effective systems aimed at early detection of failures in electrical machines and, in special cases, three-phase induction motors (TIM). These devices, coupled with predictive maintenance records, can prevent unexpected shutdowns due to malfunctions and signal the need for actions to extend the life cycle of the equipment. This is a relevant topic considering that the industrial sector is increasingly seeking for solutions based on non-destructive techniques (NDT) for preventive and predictive fault diagnosis. In this scenario, the objective of this work is to evaluate the application of a low-cost MEMS accelerometer to identify insulation failures in stator windings through vibration analysis. For this purpose, two MEMS accelerometers were coupled on either side of the frame of a TIM. Then, vibration signals were acquired for different types and levels of insulation failures. The data obtained were processed using different metrics such as root mean square (RMS), kurtosis, and skewness. The results allowed us to identify the insulation faults applied to the TIM, confirming the feasibility of applying the low-cost MEMS accelerometer in the vibration analysis for fault diagnosis.

ANN-Based Relaying Algorithm for Protection of SVC- Compensated AC Transmission Line and Criticality Analysis of a Digital Relay

2020 ◽  
Vol 13 (3) ◽  
pp. 381-393
Author(s):  
Farhana Fayaz ◽  
Gobind Lal Pahuja
Keyword(s):  
Transmission Line ◽  
Failure Modes ◽  
Reactive Power ◽  
Circuit Breaker ◽  
Research Work ◽  
Back Propagation ◽  
Static Var Compensator ◽  
Data Set ◽  
Ac Transmission ◽  
Criticality Analysis

Background:The Static VAR Compensator (SVC) has the capability of improving reliability, operation and control of the transmission system thereby improving the dynamic performance of power system. SVC is a widely used shunt FACTS device, which is an important tool for the reactive power compensation in high voltage AC transmission systems. The transmission lines compensated with the SVC may experience faults and hence need a protection system against the damage caused by these faults as well as provide the uninterrupted supply of power.Methods:The research work reported in the paper is a successful attempt to reduce the time to detect faults on a SVC-compensated transmission line to less than quarter of a cycle. The relay algorithm involves two ANNs, one for detection and the other for classification of faults, including the identification of the faulted phase/phases. RMS (Root Mean Square) values of line voltages and ratios of sequence components of line currents are used as inputs to the ANNs. Extensive training and testing of the two ANNs have been carried out using the data generated by simulating an SVC-compensated transmission line in PSCAD at a signal sampling frequency of 1 kHz. Back-propagation method has been used for the training and testing. Also the criticality analysis of the existing relay and the modified relay has been done using three fault tree importance measures i.e., Fussell-Vesely (FV) Importance, Risk Achievement Worth (RAW) and Risk Reduction Worth (RRW).Results:It is found that the relay detects any type of fault occurring anywhere on the line with 100% accuracy within a short time of 4 ms. It also classifies the type of the fault and indicates the faulted phase or phases, as the case may be, with 100% accuracy within 15 ms, that is well before a circuit breaker can clear the fault. As demonstrated, fault detection and classification by the use of ANNs is reliable and accurate when a large data set is available for training. The results from the criticality analysis show that the criticality ranking varies in both the designs (existing relay and the existing modified relay) and the ranking of the improved measurement system in the modified relay changes from 2 to 4.Conclusion:A relaying algorithm is proposed for the protection of transmission line compensated with Static Var Compensator (SVC) and criticality ranking of different failure modes of a digital relay is carried out. The proposed scheme has significant advantages over more traditional relaying algorithms. It is suitable for high resistance faults and is not affected by the inception angle nor by the location of fault.

Stiction Failure Mechanisms of the Micromachined Electrostatic Comb-Drive Structures

2011 ◽  
Vol 80-81 ◽  
pp. 850-854
Author(s):  
Yi Shen Xu ◽  
Ji Hua Gu ◽  
Zhi Tao
Keyword(s):  
Failure Modes ◽  
Failure Mechanisms ◽  
Mems Devices ◽  
Comb Drive ◽  
Interfacial Forces ◽  
Restoring Forces ◽  
Critical Investigation

Stiction is one of the most important and almost unavoidable problems in MEMS, which usually occurs when the restoring forces of the microstructures are unable to overcome the interfacial forces. Stiction could compromise the performance and reliability of the MEMS devices or may even make them malfunction. One of the pivotal process of advancing the performance and reliability of MEMS is to comprehend the failure modes and failure mechanisms of these microdevices. This article provides a critical investigation on the stiction failure mechanisms of the micromachined electrostatic comb-drive structures, which is significant to improve the reliability of microdevices, especially for microfilters, microgrippers, microaccelerometers, microgyroscopes, microrelays, and so on.

Failure Modes Model of MEMS Accelerometers Based on Neural Networks

2008 ◽  
Author(s):  
Yanping Bai ◽  
Ping An ◽  
Yilong Hao
Keyword(s):  
Neural Networks ◽  
Failure Modes ◽  
Late Phase ◽  
Primary Sources ◽  
Bp Network ◽  
Bp Networks ◽  
Mems Accelerometers ◽  
Perception Model ◽  
Hidden Layer ◽  
Training Success

Fabrication of a MEMS system involves design, testing, packaging and reliability related issues. However, reliability issues that are discovered at a late phase may cause major delays in the product development going together with high costs. In this paper we study the failure modes and Mechanisms of MEMS accelerometers products and present the classification modeling of failure modes based on neural networks. In ours MEMS accelerometers, there are six failure mechanisms that have been found to be the primary sources of failure nodes. We introduce nonlinear BP network with a hidden layer and linear perception to classify for MEMS accelerometers products. Classification results show that nonlinear BP network seem to be most appropriate to approach the problem of failure modes classification than linear perception. BP neural network is capable of learning the intrinsic relations of the patterns with which they were trained. For all experiments results, the training success of rate is 100% for both methods. BP networks obtained a high forecast success of rate of over 99.5%. The linear perception model obtained a success of rate of over 95.5%. We also analyze the technology stability of MEMS products.

Benchmarking the risk assessment in green supply chain using fuzzy approach to FMEA

2018 ◽  
Vol 25 (8) ◽  
pp. 2660-2687 ◽  
Author(s):  
Sachin Kumar Mangla ◽  
Sunil Luthra ◽  
Suresh Jakhar
Keyword(s):  
Risk Assessment ◽  
Supply Chain ◽  
Failure Mode ◽  
Failure Modes ◽  
Research Work ◽  
Evaluation Framework ◽  
Green Supply Chain ◽  
Content Type ◽  
Efficient Management ◽  
Fmea Analysis

PurposeThe purpose of this paper is to facilitate green supply chain (GSC) managers and planners to model and access GSC risks and probable failures. This paper proposes to use the fuzzy failure mode and effects analysis (FMEA) approach for assessing the risks associated with GSC for benchmarking the performance in terms of effective GSC management adoption and sustainable production.Design/methodology/approachInitially, different failure modes are defined using FMEA analysis, and in order to decide the risk priority, the risk priority number (RPN) is determined. Such priority numbers are typically acquired from the judgment decisions of experts that could contain the element of vagueness and imperfection due to human biases, and it may lead to inaccuracy in the process of risk assessment in GSC. In this study, fuzzy logic is applied to conventional FMEA to overcome the issues in assigning RPNs. A plastic manufacturer GSC case exemplar of the proposed model is illustrated to present the authenticity of this method of risk assessment.FindingsResults indicate that the failure modes, given as improper green operating procedure, i.e. process, operations, etc. (R6), and green issues while closing the loop of GSC (R14) hold the highest RPN and FRPN scores in classical as well as fuzzy FMEA analysis.Originality/valueThe present research work attempts to propose an evaluation framework for risk assessment in GSC. This paper explores both sustainable developments and risks related to efficient management of GSC initiatives in a plastic industry supply chain context. From a managerial perspective, suggestions are also provided with respect to each failure mode.

scholarly journals DEVELOPMENT OF THE BASIC CAPACITIVE ACCELEROMETERS MODELS BASED ON THE VHDL-AMS LANGUAGE FOR THE CIRCUIT LEVEL OF COMPUTER-AIDED DESIGN

2020 ◽  
Vol 2 (1) ◽  
pp. 15-20
Author(s):  
V. M. Teslyuk ◽  
◽  
P. Yu. Denysyuk ◽  
T. V. Teslyuk ◽  
◽  
...  
Keyword(s):  
Differential Equations ◽  
Computer Aided Design ◽  
Structural Parameters ◽  
Software Systems ◽  
Mems Devices ◽  
Electric Circuits ◽  
Capacitive Accelerometer ◽  
Level Of Automation ◽  
Electric Parameters ◽  
Physical Principles

In the article, the basic VHDL-AMS models of MEMS-based capacitive accelerometers were developed. The models were designed for two basic types of capacitive accelerometers, namely lamellar and counter-pivotal. The developed models allow us to determine the source of electrical capacitive accelerometers depending on the incoming mechanical and structural parameters and were constructed for MEMS CAD at the circuit level. The circuit level of MEMS development requires an analysis of the total integrated device electric circuits. For this purpose, all the MEMS components should be written in the specific software systems, which would be understandable for the software system. Taking into account that MEMS devices operate on different physical principles, certain difficulties may arise during the electrical analysis, that is, the work of mechanical or other devices need to be described with the help of electric parameters. In the general case, the method for building the VHDL-AMS model of the MEMS-based capacitive accelerometer is needed construction of the simplified mechanical model, and then a simplified electrical model. On the basis of the simplified models, the VHDL-AMS model of electromechanical MEMS devices has been developed. In the article, the method of automated synthesis and mathematical models using the VHDL-AMS language, which is based on the method of electrical analogies were described. They use systems of ordinary differential equations and partial differential equations to determine the relationships between input and output parameters. The sequence and quantity of used differential equations are determined by the physical principles of operation of the MEMS element and the number of energy transformations, which allows increasing the level of automation of synthesis operations compared to existing methods. The results of the basic lamellar and counter-pivotal capacitive accelerometers are also shown. This enables to conduct research and analysis of its parameters and investigate the output electric parameters dependence on the input mechanical ones.

Present and Future Applications of MEMS for Automotive Industry

2014 ◽  
Vol 2014 (DPC) ◽  
pp. 001851-001892
Author(s):  
Thibault Buisson
Keyword(s):  
High Pressures ◽  
Failure Mechanisms ◽  
Extreme Environments ◽  
Pressure Sensors ◽  
Harsh Environments ◽  
Fe Model ◽  
Potential Candidate ◽  
Mems Devices ◽  
Technology Modeling ◽  
Sintered Ag

MEMS are found in many applications, ranging from large volume consumer applications such as mobile phones to specific high end devices for defense or space. MEMS market will continue to see steady, sustainable double digit growth for the next six years, with 20% compound average annual growth in units and 13% growth in revenues, to become a $21 billion market by 2017. Automotive applications represent today around 20% of the MEMS market in revenue and are expected to see a 5.4 % growth in the next five years, which means that the penetration of MEMS devices in this market will remain limited. Today, MEMS family in cars is mainly represented by pressure sensors for Tire Pressure Monitoring and Manifold Air Pressure sensing, and accelerometers in ABS and stabilization systems. These applications are reaching maturity, which mean that their growth gets directly related to the car sales. To find new growth opportunities, system integrators have been trying to develop new MEMS based systems to enhance safety, comfort and reduce pollution and energy consumption. The presentation will show emerging applications and the challenges they face from a technical and a market point of view. Diverse electronic packages operate under exceptionally harsh environments, which require extended lifetimes, presenting a significant challenge for the microelectronics community. Operating temperatures above 200 °C together with high pressures, vibrations and potentially corrosive environments implies that some technical issues regarding the development of electronic systems that will operate at such high temperature remain. Technology based on sintering has been recently emerging for power modules, capable of withstanding up to 300 °C. Sintered Ag is one potential candidate for die attachment for extreme environments. The application of sintered Ag has proven already to significantly increase the lifetime of interconnects when compared to solder joints. Both characterization of the failure mechanisms as well as prediction of product life in such environments is critical to the long term reliability of these devices. The present work aims to develop an understanding of how and why attach materials for Si dies degrade/fail under harsh environments by investigating sintered Ag material. New failure mechanisms will become dominant in the sintered Ag technology. Modeling helps understanding how a particular system behaves if conditions are altered. Thus, a 2D axis symmetric die attach model, commonly used to represent microelectronic package assemblies, was generated using Ansys Workbench. The FE-model provided a good understanding of the effect of single parameter variation of different leadframe materials (K64, K14, and FeNi42), chip height, sintered Ag and metallization thicknesses. The FE-model provided a rapid assessment of delamination, cracking and other defects and their location within the package. The effect of the sintered Ag thickness on the plastic strain was only slight. Furthermore, on the chip side, the local thermal mismatch between the Si die and the sintered Ag was the most important loading factor. Also, thicker chips generated higher stresses. Further analysis of simulation and experiment of sintered Ag interconnects will give more insight on dominating failure mechanisms, and help reduce failure risks.

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