Adhesion Characteristics of Epoxy Molding Compound and Copper Leadframe Interface: Impact of Environmental Reliability Stresses

2017 ◽  
Vol 2017 (1) ◽  
pp. 000304-000311
Author(s):  
Nishant Lakhera ◽  
Sandeep Shantaram ◽  
AR Nazmus Sakib
Keyword(s):  
Finite Element ◽  
Thermal Cycling ◽  
Test Results ◽  
Adhesion Test ◽  
Bend Testing ◽  
Molding Compound ◽  
Point Bend ◽  
Cost Implications ◽  
Microelectronic Package ◽  
Bare Copper

Abstract Delamination at the mold compound and leadframe interface is the most common failure mode observed during processing and qualification of the microelectronic package. Mold compound to leadframe delamination is typically observed after environmental reliability stresses like: moisture preconditioning and reflow, air-to-air thermal cycling, biased highly accelerated stress etc. Leadframe based packages constitutes majority of microelectronic packages that are manufactured today, which makes mold compound/leadframe interface of great interest requiring thorough understanding of the adhesion characteristics and its evolution as a function of reliability stresses. This study used four-point bend testing to evaluate the adhesion strength of commercially available mold compound to bare copper and silver plated copper leadframes exposed to automotive grade environmental stresses. Results show that adhesion of mold compound to silver plated leadframes is significantly lower than adhesion to bare copper leadframes. Results obtained from this study can be used to carefully select the qualification reliability stresses to prevent overstressing the package and causing failures related to wire bond cracking, delamination etc., which have significant time and cost implications. Finite element simulations were also performed to validate the empirical adhesion test results and can be extended to full package level models to enable delamination prediction.

Bending Capacity Analyses of Corroded Pipeline

2011 ◽  
Vol 134 (2) ◽  
Author(s):  
Weiwei Yu ◽  
Pedro M. Vargas ◽  
Dale G. Karr
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Carrying Capacity ◽  
Nonlinear Finite Element ◽  
Secondary Effects ◽  
Element Analysis ◽  
Moment Capacity ◽  
Bend Testing ◽  
Bending Capacity ◽  
Point Bend

Appendix G of the ASME B31 pipeline and piping codes addresses the pressure containment capacity of pipelines and vessels with locally corroded sections. However, the ability of corroded sections to carry moment, for example, in thermal loops, is not addressed in fitness-for-service codes today. This paper presents nonlinear Finite Element Analysis (FEA) and full-scale 4-point-bend testing of pipes with locally-thinned-areas (LTAs) to simulate corrosion. The LTAs are loaded in compression, and the buckle moment is used as the carrying capacity of the corroded section. The nonlinear FEA is found to match the experimental results, validating this methodology for computing moment capacity in corroded sections. Significant secondary effects were found to affect the testing results. This paper identifies and quantifies these effects. Also, somewhat contrary to intuition, internal pressure is demonstrated to adversely affect the bending capacity for the intermediate-low D/t ratio (17.25) pipe tested.

Stress Analysis of 4-Point Bend Test for Thin Film Adhesion

2003 ◽  
Vol 778 ◽  
Author(s):  
Sassan Roham ◽  
Kedar Hardikar ◽  
Peter Woytowitz
Keyword(s):  
Finite Element Analysis ◽  
Finite Element ◽  
Classical Equation ◽  
Strength Properties ◽  
Test Results ◽  
Element Analysis ◽  
Film Adhesion ◽  
Thin Film Adhesion ◽  
Point Bend ◽  
Low K

AbstractFour point bend (4PB) tests are currently used to characterize the adhesive strength of thin films. Of particular interest are low k films whose strength properties are normally less than traditional dielectrics. A finite element analysis (FEA) of a 4PB specimen is conducted in order to better understand the results and limitations of such testing. We discuss the classical equation used to convert 4PB test data into fracture energy and have validated this classical formula using finite element analysis. We also present a theory that explains one possible reason for the occurrence of anomalous test results where the film fails in a cohesive rather than an adhesive mode.

Verification, Validation, and Uncertainty Quantification of Spinal Rod Computational Models Under Three-Point Bending

2020 ◽  
Vol 5 (1) ◽  
Author(s):  
Srinidhi Nagaraja ◽  
Galyna Loughran ◽  
Anup Gandhi ◽  
Jason Inzana ◽  
Andrew P. Baumann ◽  
...  
Keyword(s):  
Finite Element ◽  
Best Practices ◽  
Uncertainty Quantification ◽  
Medical Devices ◽  
Computational Models ◽  
Experimental Testing ◽  
Future Research ◽  
Element Analysis ◽  
Bend Testing ◽  
Point Bend

Abstract Verification, validation, and uncertainty quantification (VVUQ) can increase confidence in computational models by providing evidence that a model accurately represents the intended reality of interest. However, there are currently few examples demonstrating the application of VVUQ best practices for medical devices. Therefore, the objectives of this study were to understand the reproducibility and repeatability of experimental testing and finite element analysis (FEA), perform VVUQ activities that guide the development and refinement of a finite element model, and document best practices for future research. This study focused on experiments and simulations of three-point bend testing, which is a fundamental element of a hierarchical validation study of medical devices (e.g., spinal rod-screw systems). Experimental three-point bend testing was performed at two laboratories using medical-grade titanium (Ti-6Al-4V) spinal rods. FEA replicating the experimental test was performed by four independent institutions. Validation activities included comparing differences in mechanical properties between FEA and experimental results, where less than 10% difference was observed for all quantities of interest. Computational model uncertainties due to modeling assumptions and model input parameters were estimated using the sensitivity coefficient method. An importance factor analysis showed that rod diameter was the parameter driving uncertainty in the initial elastic region, while the material model is the primary contributor beyond this point. These results provide a proof of concept in the use of VVUQ for the use of FEA for medical device applications.

Prediction of Tread Pattern Wear by an Explicit Finite Element Model3

2007 ◽  
Vol 35 (4) ◽  
pp. 276-299 ◽  
Author(s):  
J. C. Cho ◽  
B. C. Jung
Keyword(s):  
Finite Element ◽  
Wear Rate ◽  
Tangential Stress ◽  
Rate Equation ◽  
Constitutive Equations ◽  
Slip Velocity ◽  
Test Results ◽  
Explicit Finite Element ◽  
Driving Condition ◽  
Driving Conditions

Abstract Tread pattern wear is predicted by using an explicit finite element model (FEM) and compared with the indoor drum test results under a set of actual driving conditions. One pattern is used to determine the wear rate equation, which is composed of slip velocity and tangential stress under a single driving condition. Two other patterns with the same size (225/45ZR17) and profile are used to be simulated and compared with the indoor wear test results under the actual driving conditions. As a study on the rubber wear rate equation, trial wear rates are assumed by several constitutive equations and each trial wear rate is integrated along time to yield the total accumulated wear under a selected single cornering condition. The trial constitutive equations are defined by independently varying each exponent of slip velocity and tangential stress. The integrated results are compared with the indoor test results, and the best matching constitutive equation for wear is selected for the following wear simulation of two other patterns under actual driving conditions. Tens of thousands of driving conditions of a tire are categorized into a small number of simplified conditions by a suggested simplification procedure which considers the driving condition frequency and weighting function. Both of these simplified conditions and the original actual conditions are tested on the indoor drum test machines. The two results can be regarded to be in good agreement if the deviation that exists in the data is mainly due to the difference in the test velocity. Therefore, the simplification procedure is justified. By applying the selected wear rate equation and the simplified driving conditions to the explicit FEM simulation, the simulated wear results for the two patterns show good match with the actual indoor wear results.

scholarly journals Theoretical analysis and experimental research on multi-layer elastic damping track structure

2021 ◽  
Vol 13 (2) ◽  
pp. 168781402199497
Author(s):  
Guanghui Xu ◽  
Shengkai Su ◽  
Anbin Wang ◽  
Ruolin Hu
Keyword(s):  
Finite Element ◽  
Analytical Solution ◽  
Finite Element Simulation ◽  
Reaction Force ◽  
Vibration Reduction ◽  
Vertical Direction ◽  
Propagation Path ◽  
Track Structure ◽  
Test Results ◽  
Element Simulation

The increase of axle load and train speed would cause intense wheelrail interactions, and lead to potential vibration related problems in train operation. For the low-frequency vibration reduction of a track system, a multi-layer track structure was proposed and analyzed theoretically and experimentally. Firstly, the analytical solution was derived theoretically, and followed by a parametric analysis to verify the vibration reduction performance. Then, a finite element simulation is carried out to highlight the influence of the tuned slab damper. Finally, the vibration and noise tests are performed to verify the results of the analytical solution and finite element simulation. As the finite element simulation indicates, after installation of the tuned slab damper, the peak reaction force of the foundation can be reduced by 60%, and the peak value of the vertical vibration acceleration would decrease by 50%. The vibration test results show that the insertion losses for the total vibration levels are 13.3 dB in the vertical direction and 21.7 dB in the transverse direction. The noise test results show that the data of each measurement point is smoother and smaller, and the noise in the generating position and propagation path can be reduced by 1.9 dB–5.5 dB.

Finite Element Analysis of Reinforced Concrete Beams with Exterior FRP Shell

2011 ◽  
Vol 243-249 ◽  
pp. 1461-1465
Author(s):  
Chuan Min Zhang ◽  
Chao He Chen ◽  
Ye Fan Chen
Keyword(s):  
Mechanical Properties ◽  
Finite Element Analysis ◽  
Finite Element ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Reinforced Concrete Beams ◽  
Test Results ◽  
Contact Interface ◽  
Accurate Calculation ◽  
Element Analysis

The paper makes an analysis of the reinforced concrete beams with exterior FRP Shell in Finite Element, and compares it with the test results. The results show that, by means of this model, mechanical properties of reinforced concrete beams with exterior FRP shell can be predicted better. However, the larger the load, the larger deviation between calculated values and test values. Hence, if more accurate calculation is required, issues of contact interface between the reinforced concrete beams and the FRP shell should be taken into consideration.

scholarly journals Reliability Evaluation of Fan-Out Type 3D Packaging-On-Packaging

Micromachines ◽  
2021 ◽  
Vol 12 (3) ◽  
pp. 295
Author(s):  
Pao-Hsiung Wang ◽  
Yu-Wei Huang ◽  
Kuo-Ning Chiang
Keyword(s):  
Finite Element ◽  
Thermal Cycling ◽  
Glass Substrate ◽  
High Speed ◽  
Coefficient Of Thermal Expansion ◽  
Three Dimensional ◽  
Design Parameters ◽  
Time To Failure ◽  
Wafer Level ◽  
Fine Pitch

The development of fan-out packaging technology for fine-pitch and high-pin-count applications is a hot topic in semiconductor research. To reduce the package footprint and improve system performance, many applications have adopted packaging-on-packaging (PoP) architecture. Given its inherent characteristics, glass is a good material for high-speed transmission applications. Therefore, this study proposes a fan-out wafer-level packaging (FO-WLP) with glass substrate-type PoP. The reliability life of the proposed FO-WLP was evaluated under thermal cycling conditions through finite element simulations and empirical calculations. Considering the simulation processing time and consistency with the experimentally obtained mean time to failure (MTTF) of the packaging, both two- and three-dimensional finite element models were developed with appropriate mechanical theories, and were verified to have similar MTTFs. Next, the FO-WLP structure was optimized by simulating various design parameters. The coefficient of thermal expansion of the glass substrate exerted the strongest effect on the reliability life under thermal cycling loading. In addition, the upper and lower pad thicknesses and the buffer layer thickness significantly affected the reliability life of both the FO-WLP and the FO-WLP-type PoP.

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