An Investigation Into the Effect of the PCB Motion on the Dynamic Response of MEMS Devices Under Mechanical Shock Loads

2008 ◽  
Vol 130 (3) ◽  
Author(s):  
Fadi Alsaleem ◽  
Mohammad I. Younis ◽  
Ronald Miles
Keyword(s):  
Printed Circuit Board ◽  
Electrostatic Force ◽  
Single Point ◽  
Circuit Board ◽  
Mechanical Shock ◽  
Shock Pulse ◽  
Mems Devices ◽  
Case Scenario ◽  
Worst Case ◽  
Shock Loads

We present an investigation into the effect of the motion of a printed circuit board (PCB) on the response of a microelectromechanical system (MEMS) device to shock loads. A two-degrees-of-freedom model is used to model the motion of the PCB and the microstructure, which can be a beam or a plate. The mechanical shock is represented as a single point force impacting the PCB. The effects of the fundamental natural frequency of the PCB, damping, shock pulse duration, electrostatic force, and their interactions are investigated. It is found that neglecting the PCB effect on the modeling of MEMS under shock loads can lead to erroneous predictions of the microstructure motion. Further, contradictory to what is mentioned in literature that a PCB, as a worst-case scenario, transfers the shock pulse to the microstructure without significantly altering its shape or intensity, we show that a poor design of the PCB or the MEMS package may result in severe amplification of the shock effect. This amplification can cause early pull-in instability for MEMS devices employing electrostatic forces.

Ocean Sensor “Imaging” Arrays Based on Bio-inspired Architectures and 2-D/3-D Construction

2015 ◽  
Vol 49 (3) ◽  
pp. 43-49 ◽  
Author(s):  
David P. Fries ◽  
Chase A. Starr ◽  
Geran W. Barton
Keyword(s):  
Flexible Electronics ◽  
Printed Circuit Board ◽  
Single Point ◽  
Circuit Board ◽  
Sensor Systems ◽  
Large Area ◽  
Imaging Arrays ◽  
Printed Circuits ◽  
Single Sensor ◽  
New Vision

AbstractMany common ocean sensor systems measure a localized space above a single sensor element. Single-point measurements give magnitude but not necessarily direction information. Expanding single sensor elements, such as used in salinity sensors, into arrays permits spatial distribution measurements and allows flux visualizations. Furthermore, applying microsystem technology to these macro sensor systems can yield imaging arrays with high-resolution spatial/temporal sensing functions. Extending such high spatial resolution imaging over large areas is a desirable feature for new “vision” modes on autonomous robotic systems and for deployable ocean sensor systems. The work described here explores the use of printed circuit board (PCB) technology for new sensing concepts and designs. In order to create rigid-conformal, large area imaging “camera” systems, we have merged flexible PCB substrates with rigid constructions from 3-D printing. This approach merges the 2-D flexible electronics world of printed circuits with the 3-D printed packaging world. Furthermore, employing architectures used by biology as a basis for our imaging systems, we explored naturally and biologically inspired designs, their relationships to visual imagining, and alternate mechanical systems of perception. Through the use of bio-inspiration, a framework is laid out to base further research on design for packaging of ocean sensors and arrays. Using 3-D printed exoskeleton's rigid form with flexible printed circuits, one can create systems that are both rigid and form-fitting with 3-D shape and enable new sensor systems for various ocean sensory applications.

I/O Printed Circuit Board Assemblies; Recent Learning in Mechanical Stress Analysis, Verification Testing, and Post-test Analysis Techniques and Results

2015 ◽  
Vol 2015 (1) ◽  
pp. 000169-000178
Author(s):  
John Torok ◽  
Shawn Canfield ◽  
Suraush Khambati ◽  
Robert Mullady ◽  
Budy Notohardjono ◽  
...  
Keyword(s):  
Printed Circuit Board ◽  
Measurement Techniques ◽  
Form Factors ◽  
Mechanical Analysis ◽  
Circuit Board ◽  
Mechanical Shock ◽  
Test Analysis ◽  
Printed Circuit ◽  
Analysis Techniques ◽  
Post Test

Recent high-end server designs have included new Input / Output (I/O) printed circuit board (PCB) assemblies consisting of a variety of form factors, electronic design layouts, and packaging assembly characteristics. To insure the required functional and reliability aspects are established and maintained, new mechanical analysis and verification testing techniques have been recently devised. A description of the design application set, the analysis tools and techniques applied, and the verification testing completed, including the associated measurement techniques as well as post-testing analysis methods and results are presented. Also included are the recent PCB raw card characterization efforts whose results have been applied as material property inputs to the analysis to improve analytical-to-empirical correlation. Included within the application set are both the use of custom designed cards as well as industry standard, original equipment manufacturer (OEM) cards that are packaged within custom enclosures. Given packaged and unpackaged (i.e., as installed in a higher-level rack system assembly) fragility testing requirements, new analysis techniques exploiting the capabilities of LS-DYNA have been used to provide a predictive means to support both initial as well as iterative design levels. In addition, these analysis results are also used to identify locations for measurement sensor placement employed during mechanical verification testing. Thermal shock and mechanical shock and vibration verification testing details and results are provided describing the conditions applied to simulate assembly shipping conditions, both as packaged as well as in situ to the higher-level of assembly. Included with this is a discussion with respect to post-test analysis techniques and results, including the use of both microscopic cross-section analysis as well as dye-pry assessments. Concluding, continued and future activities are described as “best practices” for the application of this methodology as part of the end-to-end development process.

Mechanical Stress Analysis and Evaluation of Hybrid Land Grid Array Attached Large Form Factor Organic Modules

2012 ◽  
Vol 2012 (1) ◽  
pp. 000818-000824
Author(s):  
John Torok ◽  
Shawn Canfield ◽  
Yuet-Ying Yu ◽  
Jiantao Zheng
Keyword(s):  
Form Factor ◽  
Stress Analysis ◽  
Mechanical Stress ◽  
Printed Circuit Board ◽  
Organic Substrate ◽  
Circuit Board ◽  
Bottom Surface ◽  
Mechanical Shock ◽  
Analysis And Evaluation ◽  
Pcb Assembly

Recent industry trends to continue enabling increased server system performance and packaging density has driven the need to implement larger form factor hybrid land grid array (LGA) attached organic modules. In addition, given the need to package multiple modules on a single printed circuit board (PCB) assembly, PCB cross-sections and their corresponding physical properties (e.g., flatness, etc.) as well as module bottom surface metallurgy (BSM) co-planarity require a more detailed understanding of impacts to the compliant as well as the soldered connector interfaces. Lastly, the migration to lead (Pb)-free solders has further complicated the issue given both the change in material properties as well as processing temperatures. In this paper we will discuss the mechanical stress analysis and evaluation tests assessment of a recently developed 50 mm square organic processor module, hybrid LGA attached to a multiple site PCB. The analysis presented will highlight the methodology to identify both connector soldered stress and predicted contact load variation across the module's mated interface. Key parameters discuss will include the PCB flatness, Organic substrate BSM co-planarity (both predicted and measured) and the Hybrid LGA as-soldered contact co-planarity. Corroborating predicted analytical results, we will discuss various evaluation tests performed to validate the design's integrity. Key tests include, pressure sensitive film (PSF) studies and environment stress exposures, including thermal shock, mechanical shock and vibration and seismic exposure. Post test electrical integrity and test sample construction analysis, including 3D x-ray and mechanical cross-section, will also be described. The analysis process and testing described will provide a method to evaluate more challenging hybrid LGA applications as both module sizes and/or number applied per PCB assembly increase and Pb-free assembly is introduced in future applications.

Process-Induced Thermal Effect on Packaging Yield of RF MEMS Switches

2002 ◽  
Author(s):  
Lei L. Mercado ◽  
Shun-Meen Kuo ◽  
Tien-Yu Tom Lee ◽  
Russ Lee
Keyword(s):  
Printed Circuit Board ◽  
Failure Modes ◽  
Rf Mems ◽  
Electrostatic Force ◽  
Circuit Board ◽  
Mems Switches ◽  
Rf Mems Switches ◽  
Significant Performance ◽  
And Performance ◽  
Lower Temperature

RF MEMS switches offer significant performance advantages in high frequency RF applications. The switches are actuated by electrostatic force when voltage was applied to the electrodes. Such devices provide high isolation when open and low contact resistance when closed. However, during the packaging process, there are various possible failure modes that may affect the switch yield and performance. The RF MEMS switches were first placed in a package and went through lid seal at 320°C. The assembled packages were then attached to a printed circuit board at 220°C. During the process, some switches failed due to electrical shorting. More interestingly, more failures were observed at the lower temperature of 220°C rather than 320°C. The failure mode was associated with the shorting bar and the cantilever design. Finite element simulations and simplified analytical solutions were used to understand the mechanics driving the behaviors. Simulation results have shown excellent agreement with experimental observations and measurements. Various solutions in package configurations were explored to overcome the hurdles in MEMS packaging and achieve better yield and performance.

Damage and Failures of CGA/BGA Assemblies Under Thermal Cycling and Dynamic Loadings

2013 ◽  
Author(s):  
Reza Ghaffarian
Keyword(s):  
Thermal Cycling ◽  
Mechanical Loading ◽  
Test Data ◽  
Printed Circuit Board ◽  
High Reliability ◽  
Circuit Board ◽  
Design Parameters ◽  
Mechanical Shock ◽  
Space Applications ◽  
High Processing

Commercial-off-the-shelf column/ball grid array packaging (COTS CGA/BGA) technologies in high-reliability versions are now being considered for use in high-reliability electronic systems. For space applications, these packages are prone to early failure due to the severe thermal cycling in ground testing and during flight, mechanical shock and vibration of launch, as well as other less severe conditions, such as mechanical loading during descent, rough terrain mobility, handling, and ground tests. As the density of these packages increases and the size of solder interconnections decreases, susceptibility to thermal, mechanical loading and cycling fatigue grows even more. This paper reviews technology as well as thermo-mechanical reliability of field programmable gate array (FPGA) IC packaging developed to meet demands of high processing powers. The FPGAs that generally come in CGA/PBGA packages now have more than thousands of solder balls/columns under the package area. These packages need not only to be correctly joined onto printed circuit board (PCB) for interfacing; they also should show adequate system reliability for meeting thermo-mechanical requirements of the electronics hardware application. Such reliability test data are rare or none for harsher environmental applications, especially for CGAs having more than a thousand of columns. The paper also presents significant test data gathered under thermal cycling and drop testing for high I/O PBGA/CGA packages assembled onto PCBs. Damage and failures of these assemblies after environmental exposures are presented in detail. Understanding the key design parameters and failure mechanisms under thermal and mechanical conditions is critical to developing an approach that will minimize future failures and will enable low-risk insertion of these advanced electronic packages with high processing power and in-field re-programming capability.

Analysis and monitoring of IoT-assisted human physiological galvanic skin responsefactor for smart e-healthcare

Sensor Review ◽  
2019 ◽  
Vol 39 (4) ◽  
pp. 525-541 ◽  
Author(s):  
Partha Pratim Ray ◽  
Dinesh Dash ◽  
Debashis De
Keyword(s):  
User Experience ◽  
Printed Circuit Board ◽  
System Development ◽  
Flexible Substrate ◽  
Cost Effective ◽  
Circuit Board ◽  
Sensor System ◽  
Case Scenario ◽  
Content Type ◽  
Flexible System

Purpose Background: Every so often, one experiences different physically unstable situations which may lead to possibilities of suffering through vicious physiological risks and extents. Dynamic physiological activities are such a key metric that they are perceived by means of measuring galvanic skin response (GSR). GSR represents impedance of human skin that frequently changes based on different human respiratory and physical instability. Existing solutions, paved in literature and market, focus on the direct measurement of GSR by two sensor-attached leads, which are then parameterized against the standard printed circuit board mechanism. This process is sometimes cumbersome to use, resulting in lower user experience provisioning and adaptability in livelihood activities. The purpose of this study is to validate the novel development of the cost-effective GSR sensing system for affective usage for smart e-healthcare. Design/methodology/approach This paper proposes to design and develop a flexible circuit strip, populated with essential circuitry assemblies, to assess and monitor the level of GSR. Ordinarily, this flexible system would be worn on the back palm of the hand where two leads would contact two sensor strips worn on the first finger. Findings The system was developed on top of Pyralux. Initial goals of this work are to design and validate a flexible film-based GSR system to detect an individual’s level of human physiological activities by acquiring, amplifying and processing GSR data. The measured GSR value is visualized “24 × 7” on a Bluetooth-enabled smartphone via a pre-incorporated application. Conclusion: The proposed sensor-system is capable of raising the qualities such as adaptability, user experience, portability and ubiquity for possible application of monitoring of human psychodynamics in a more cost-effective way, i.e. less than US$50. Practical implications Several novel attributes are envisaged in the development process of the GSR system that made it different from and unique as compared to the existing alternatives. The attributes are as follows: (i) use of reproductive sensor-system fabrication process, (ii) use of flexible-substrate for hosting the system as proof of concept, (iii) use of miniaturized microcontroller, i.e. ATTiny85, (iv) deployment of energy-efficient passive electrical circuitry for noise filtering, (v) possible use case scenario of using CR2032 coin battery for provisioning powering up the system, (vi) provision of incorporation of internet of things (IoT)-cloud integration in existing version while fixing related APIs and (vii) incorporation of heterogeneous software-based solutions to validate and monitor the GSR output such as MakerPlot, Arduino IDE, Fritzing and MIT App Inventor 2. Originality/value This paper is a revised version R1 of the earlier reviewed paper. The proposed paper provides novel knowledge about the flexible sensor system development for GSR monitoring under IoT-based environment for smart e-healthcare.

Response of a Flexible Printed Circuit Board to Periodic Shock Loads Applied to its Support Contour

1992 ◽  
Vol 59 (2S) ◽  
pp. S253-S259 ◽  
Author(s):  
E. Suhir
Keyword(s):  
Steady State ◽  
Printed Circuit Board ◽  
Circuit Board ◽  
Shock Loads ◽  
Printed Circuit ◽  
Periodic Shock ◽  
Flexible Printed Circuit ◽  
Linear Vibrations ◽  
Flexible Rectangular Plate ◽  
Support Conditions

Treating a printed circuit board (PCB) as a thin flexible rectangular plate, we evaluate its dynamic response to periodic shock loads applied to the support contour. The effect of the load periodicity on the amplitudes, accelerations, and stresses is analyzed for transient and steady-state damped linear vibrations, as well as for steady-state undamped nonlinear vibrations. It is shown that the transient nonresonant linear response can exceed the steady-state response by up to two times, and that the linear approach can be misleading in the case of a nondeformable support contour and intense loading. The obtained results can be of help when evaluating the accelerations, experienced by surface mounted electronic components and devices, and the dynamic stresses in a PCB of the given type, dimensions, and support conditions.

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.

Fabrication of micro-mixer on printed circuit board using electrochemical micromachining

2019 ◽  
Vol 2 (2) ◽  
pp. 85-94
Author(s):  
Jitendra Singh ◽  
Shantanu Bhattacharya
Keyword(s):  
Printed Circuit Board ◽  
Complex Geometry ◽  
Single Point ◽  
Machining Process ◽  
Circuit Board ◽  
Electrochemical Micromachining ◽  
Geometrical Parameters ◽  
Feature Size ◽  
Printed Circuit ◽  
Micro Mixer

Electrochemical micromachining (ECMM) has been mostly carried out in situations demanding precision, complexity in the shapes of final components and in case the surface integrity and performance are independent of the machining process. In this work, the following have been demonstrated: The first part of the work demonstrates the experimental setup for ECMM that is used to fabricate a micro-mixer on a printed circuit board (PCB) substrate by using a single point electrochemical machining tool with a tip diameter—150 µm. The method is able to show a promising route of fabrication where the circuit lines on a PCB substrate can be printed with high yield and processing speeds. The second part of the article points out that machining can be carried out on PCB substrates through electrochemical processes using a single point tool and a minimum feature size of 243 µm can be machined with a fine tolerance of 0.025 µm and roughness = 3.0459 µm~7.2404 µm. The third part of the article reports the geometrical parameters of a relatively complex geometry of a micro-mixer which is arrived at through a COMSOL based simulation platform that is fabricated using the mentioned manufacturing process. The process is further validated through the design of experiments, and fluid flow and mixing behaviour on the fabricated structure is evaluated through an epifluorescence microscope. The advantages that this technique may offer is in terms of achieving an overall low feature size in comparison to micro-milling and avoiding the complexities of lithography-driven processes to produce a process which has a much lower equipment dependency, is environmentally benign in comparison to the lithography driven techniques and is overall low in cost.

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