Reliability Studies for Package-on-Package Components in Drop and Shock Environments

Author(s):  
Pradeep Lall ◽  
Arjun Angral ◽  
Jeff Suhling

The consumer electronics industry stands at a critical juncture where manufacturers strive to incorporate more functionality in smaller packages. In the highly competitive consumer electronics market, a continued demand for products with smallest possible form-factor yet high functionality has led to the proliferation of 3D packaging technologies. Package-on-Package (PoP) architectures, in particular have attracted a lot of interest, especially in portable electronics industry. The advantages of these stacked 3D architectures include simplified and compact design, savings of board space allowing for more package landings, reduced pin counts and optimized production costs. While a lot of recent research, in the field of PoP architectures has been focused on development of optimum process flows and warpage control during reflow, the effects of reflow parameters on the quality of PoP build and the associated reflow defects including warpage have not been extensively researched. Additionally, studies on reliability issues associated with PoP assemblies in drop and shock environments are scarce. Since PoP architectures find their applications mainly in portable electronics, which are susceptible to frequent drops and careless handling at the hand of the consumer, the reliability of PoP architectures in environments representative of the real world is critical to their success in the industry. In this study, Single component PoP test vehicles have been fabricated as per JEDEC standards for quantifying the reliability of PoP packages in drop and shock. Daisy chained double-stack PoP components have been used to identify failure for subsequent drop/shock performance analysis. Experimental strain data acquired using Digital Image Correlation and high speed continuity data- for identifying failure has been used in conjunction with validated FE simulations of drop test events; for development of life prediction models for PoP architectures. Validated node based global-local FE simulations are used to predict strains in critical solder balls in both layers of the PoP stack. The drop/shock reliability studies and life prediction models presented in this work, present an insight into PoP failures and eliminate the need for exhaustive testing procedures.

2016 ◽  
Vol 85 ◽  
pp. 98-113 ◽  
Author(s):  
Punit Arora ◽  
Suneel K. Gupta ◽  
V. Bhasin ◽  
R.K. Singh ◽  
S. Sivaprasad ◽  
...  

2012 ◽  
Vol 06 ◽  
pp. 251-256
Author(s):  
HO-YOUNG YANG ◽  
JAE-HOON KIM ◽  
KEUN-BONG YOO

Co -base superalloys have been applied in the stationary components of gas turbine owing to their excellent high temperature properties. Low cycle fatigue data on ECY-768 reported in a companion paper were used to evaluate fatigue life prediction models. In this study, low cycle fatigue tests are performed as the variables of total strain range and temperatures. The relations between plastic and total strain energy densities and number of cycles to failure are examined in order to predict the low cycle fatigue life of Cobalt-based super alloy at different temperatures. The fatigue lives is evaluated using predicted by Coffin-Manson method and strain energy methods is compared with the measured fatigue lives at different temperatures. The microstructure observing was performed for how affect able to low-cycle fatigue life by increasing the temperature.


Author(s):  
Pradeep Lall ◽  
Sandeep Shantaram ◽  
Arjun Angral ◽  
Mandar Kulkarni ◽  
Jeff Suhling

Relative damage-index based on the leadfree interconnect transient strain history from digital image correlation, explicit finite-elements, cohesive-zone elements, and component’s survivability envelope has been developed for life-prediction of two-leadfree electronic alloy systems. Life prediction of pristine and thermally-aged assemblies, have been investigated. Solder alloy system studied include Sn1Ag0.5Cu, and 96.5Sn3.5Ag. Transient strains during the shock-impact have been measured using digital image correlation in conjunction with high-speed cameras operating at 50,000 fps. Both the board strains and the package strains have been measured in a variety of drop orientations including JEDEC horizontal drop orientation, vertical drop orientation and intermediate drop orientations. In addition the effect of sequential stresses of thermal aging and shock-impact on the failure mechanisms has also been studied. The thermal aging condition used for the study includes 125°C for 100 hrs. The presented methodology addresses the need for life prediction of new lead-free alloy-systems under shock and vibration, which is largely beyond the state of art. Three failure modes have been predicted including interfacial failure at the copper-solder interface, solder-PCB interface, and the solder joint failure. Explicit non-linear finite element models with cohesive-zone elements have been developed and correlated with experimental results. Velocity data from digital image correlation has been used to drive the attachment degrees of freedom of the submodel and extract transient interconnect strain histories. Explicit finite-element sub-modeling has been correlated with the full-field strain in various locations, orientations, on both the package and the board-side. The survivability of the leadfree interconnections under sequential loading (thermal aging and shock-impact) from simulation has been compared with pristine circuit assemblies subjected to shock-impact. Sequential loading changes the failure modes and decreases the drop reliability as compared to the room temperature experimental results. Damage index based survivability envelope is intended for component integration to ensure reliability in harsh environments.


Sensors ◽  
2021 ◽  
Vol 21 (24) ◽  
pp. 8420
Author(s):  
Muhammad Mohsin Khan ◽  
Peter W. Tse ◽  
Amy J.C. Trappey

Smart remaining useful life (RUL) prognosis methods for condition-based maintenance (CBM) of engineering equipment are getting high popularity nowadays. Current RUL prediction models in the literature are developed with an ideal database, i.e., a combination of a huge “run to failure” and “run to prior failure” data. However, in real-world, run to failure data for rotary machines is difficult to exist since periodic maintenance is continuously practiced to the running machines in industry, to save any production downtime. In such a situation, the maintenance staff only have run to prior failure data of an in operation machine for implementing CBM. In this study, a unique strategy for the RUL prediction of two identical and in-process slurry pumps, having only real-time run to prior failure data, is proposed. The obtained vibration signals from slurry pumps were utilized for generating degradation trends while a hybrid nonlinear autoregressive (NAR)-LSTM-BiLSTM model was developed for RUL prediction. The core of the developed strategy was the usage of the NAR prediction results as the “path to be followed” for the designed LSTM-BiLSTM model. The proposed methodology was also applied on publically available NASA’s C-MAPSS dataset for validating its applicability, and in return, satisfactory results were achieved.


2020 ◽  
Author(s):  
Aodi Yu ◽  
Hong-Zhong Huang ◽  
Yan-Feng Li ◽  
He Li ◽  
Ying Zeng

Abstract Mean stress has a great influence on fatigue life, commonly used stress-based life prediction models can only fit the test results of fatigue life under specific stress ratio or mean stress but cannot describe the effect of stress ratio or mean stress on fatigue life. Smith, Watson and Topper (SWT) proposed a simple mean stress correction criterion. However, the SWT model regards the sensitivity coefficient of all materials to mean stress as 0.5, which will lead to inaccurate predictions for materials with a sensitivity coefficient not equal to 0.5. In this paper, considering the sensitivity of different materials to mean stresses, compensation factor is introduced to modify the SWT model, and several sets of experimental data are used for model verification. Then, the proposed model is applied to fatigue life predictions of rolling bearings, and the results of proposed method are compared with test results to verify its accuracy.


2011 ◽  
Vol 465 ◽  
pp. 47-54 ◽  
Author(s):  
Stephen D. Antolovich ◽  
Robert L. Amaro ◽  
Richard W. Neu ◽  
A Staroselsky

In a world increasingly concerned with environmental factors and efficient use of resources, increasing operating temperatures of high temperature machinery can play an important role in meeting these goals. In addition, the cost of failure of such devices is rapidly becoming prohibitive. For example, in an airline crash airframe and engine manufacturers are, on average, held liable for 1,000,000 euros per fatality excluding the loss of property. Thus there is considerable pressure to make machinery that can operate much more safely at high temperatures. This means that the old ways of guarding against high temperature fatigue failure (e.g. factor of safety, S/N curves, creep life) are no longer acceptable; more reliable, accurate, and efficient means are needed to manage life, durability and risk. In this paper, high temperature fatigue is considered in terms of past successes and current challenges. Particular emphasis is placed on understanding damage mechanisms and their interactions both in terms of scientific interest and technological importance. Materials used in nuclear reactors (e.g. selected steels and solid solution Ni-base alloys) and in hot sections of jet engines (e.g. superalloys) are used as vehicles to illustrate damage evolution and interaction. Phenomenological life prediction models are presented and compared with physics-based damage evolution/interaction models which are based on observed physical processes such as creep/fatigue/environment interactions. It is shown that in many cases, in spite of the emphasis on creep-fatigue interactions, the most damaging forms of damage that occur under thermo-mechanical fatigue (TMF) loading result from the interaction of slip bands with oxidized boundaries.


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