Two major drivers in electronic industry are electrical and mechanical miniaturization. Both induce major changes in the material selection as well as in the design. Nevertheless,the mechanical and thermal reliability of a Printed Circuit Board (PCB) has to remain at the same high level or even increase (e.g. multiple lead-free soldering). To achieve these reliability targets,extensive testing has to be done with bare PCB as well as assembled PCB. These tests are time consuming and cost intensive. The PCBs have to be produced,assembled,tested and finally a detailed failure analysis is required to be performed.
This paper examines the development of our concept and has the potential to enable the prediction of the lifetime of the PCB using accelerated testing methods and finite element simulations.
The method of evaluation for the developed concept uses the mechanical loading (drop test) on Printed Circuit Board Assembly (PCBA) test vehicles.
The aim of this study is to show,that experiments on material specimen level in combination with corresponding simulation models,allow a significant reduction of previously required board level tests. Doing so characteristic failure curves,correlating simulated local failure parameters to measured lifetimes,were generated and used to predict the performance of unknown PCB types. Applied tools,in order to determine relevant local failure parameters,were based on fracture mechanics concepts,as e.g. X-FEM and contour integral simulations.
This research was carried out by Austria Technologie & Systemtechnik AG (AT&S AG) in cooperation with the Polymer Competence Center Leoben (PCCL).

Recycling cleaning and rinsing fluids in the manufacturing process is becoming very popular for many reasons. Competitiveness is the key issue as the electronics industry ages. In our golden years,paying attention to the expenses is very important in managing the bottom line. Up to 50% of the monthly utility bills to run the manufacturing line can be related to cleaning the product. Implementing fluid recycling can feed the savings and align management with a positive environmental impact and improved employee health and safety. Accelerating this change is management’s awareness of new and proposed government regulations to protect the work force and the environment. The purpose of this paper is to provide an understanding of how to achieve these targets at the lowest possible cost.
Choosing the best recycling system requires knowledge of the cleaning process and current available recycling technologies. Recycling systems can be specific to a cleaning fluid type. In some instances,the cleaning fluid can be changed to a more recycling friendly fluid. Fluid properties such as alkalinity or flammability can complicate the selection process. Understanding the cleaning process,the fluids used,and appropriate recycling technologies available is very important in selecting a lean and green cleaning process that meets the planned corporate targets.
In situ machine recycling has become the new standard for new cleaning systems. These systems recycle the cleaning fluids in the machine versus sending the fluids to a remote location in the plant or to a third party recycler. These systems can be built into new or existing cleaners. Recycling the cleaning fluids within the cleaner,almost always gives the lowest cost due to reduction of logistics,storage,transport,and third party charges. A cost model should be used to evaluate the choices and select the best options for your cleaning process. To better illustrate the decision process,A cost model is evaluated to compare an open loop aqueous inline cleaner,a remotely located closed loop inline and a in situ closed loop inline. The cost model with field data is used to estimate the cost savings of recycling for each system.

The purpose of this study is to determine whether or not aerosol benchtop cleaning can consistently and reliably clean reworked boards. Different variables that play a role in the effectiveness of aerosol benchtop cleaning were examined. These variables include straw attachment,spray technique,spray angle,handheld cleaning tools,brush attachments,and a final rinse. While no approach to aerosol benchtop cleaning was found to be 100% effective all of the time,the study did yield good information that can be used as general guidelines to improve benchtop cleaning processes.

Over the last years more and more International newspapers reported in Europe / USA and Japan: “Tunnel train got stuck under the Channel – thousands of people stranded “Recall of thousands of cars to workshops for control and repair Power Failures left households without energy for hours. Very often news like this relate to malfunctions of electric and electronic circuits under adverse conditions or sometimes even in normal operating environment.
Considering that in the automotive industry – one of the most dynamic and innovative driving economic force in industrialized countries the number of complex electronic circuits will increase drastically over the next decade - ensuring reliability will become a focus in high- quality electronics production.
Highly integrated circuitry and the permanent miniaturization makes high quality production more and more crucial.
The reliability of such complex circuitry can be ensured using cleaning in all steps of the production process,from stencil cleaning to PCB cleaning prior to coating or painting in order to increase the reliability and life span of the units into which such circuitry will be installed.
The use of environmentally friendly water based chemistries instead of ozone layer depleting VOC-containing solvents – once the standard in the electronics industry- as well as the use of respective machines that operate under the condition of saving energy and resources will gain more and more importance and cannot be neglected anymore.
The presentation will deal with all kinds of aspect of cleaning to ensure the reliability of electronic circuitry in ever changing operation conditions in the most important industrial areas.

This paper examines the nature; the consequences and the mitigation of electrical overstress (EOS) caused by electromagnetic interference (EMI),or electrical noise,on power lines and ground in manufacturing environment.

BGA Rework is now largely mature,although new supplemental processes that provide improved process control such as
Solder Paste Dipping and Non-Contact Site Cleaning can now be integrated into existing processes if the rework technology that is used allows. So what are the next set of challenges that will need to be addressed in regard to Area Array and SMT Rework? The
International Electronics Manufacturing Initiative or iNEMI has recently published its 2013 Technology Roadmap for the
global electronics industry which includes a section dedicated specifically to rework and repair. Of particular interest and importance is iNEMI’s gap analysis which identifies future specific gaps and challenges that will result from such factors as
government regulations,disruptive technologies and new product requirements. This paper will review five of the key rework gaps and challenges identified by iNEMI including: 1) Reworking very large,next generation area arrays on large high thermal mass assemblies. 2) Development of hand soldering processes for reworking 01005 components. 3) Development of industry-standardized processes for reworking Package-on-Package (PoP) devices. 4) Development of industry-standardized processes for reworking Quad Flat,No Lead (QFN) devices. 5) Development of site redressing processes that prevent lifted pads,solder mask damage and copper dissolution
The objective of this paper is to discuss the five iNEMI rework gaps and challenges including identification of the key technical/process challenges,outlining in detail the efforts-to-date aimed at addressing these new challenges as well as the
next steps required for complete resolution of these challenges.

Commercial-off-the-shelf column grid array packaging (COTS CGA) technologies in high reliability versions are now being considered for use in a number of National Aeronautics and Space Administration (NASA) electronic systems. Understanding the process and quality assurance (QA) indicators for reliability are important for low-risk insertion of these advanced electronic packages. This paper presents rework and re-column attachment of two high input/output (I/O) CCGA (CGA) packages (560 and 1144 I/Os). Subsequent to re-column attachment and isothermal aging,the integrity of tin-lead solder-column attachment was determined and presented. In addition,the process-control parameters for assembly of re-columned CGA packages using either vapor-phase or rework stations were established for both package types/sizes. Details of these process control parameters solder paste-print uniformity as well as quality assurance indicators based on visual inspection before and during thermal cycling tests are presented. Qualification guidelines generated based on these and additional optical photomicrographs,X-rays,SEMs,and destructive cross-sectioning of thermally cycled,reworked,re-columned,and re-assembled test vehicles of these CGAs are presented in detail.

Assembly defects can effectively shorten reliability lifetimes in addition to lowering manufacturing yields or creating premature service failures. This paper describes and characterizes an unusual open circuit failure mechanism in Pb-free ball grid array (BGA) solder joints. The failure occurred during Pb-free solder assembly of a 31 mm,1.27 mm pitch,perimeter array,SAC305 (Sn3.0Ag0.5Cu) BGA. Due to design constraints,it was necessary to assemble some BGA components during the first reflow cycle. Following the second reflow operation,some solder joint opens were detected on the BGA component which had been subjected to the atypical second reflow exposure. Metallographic cross sectional analysis indicated that the open solder joints initially were well-formed but the failure resulted from a brittle interfacial fracture at the package side of the solder joints. The failure mechanism and possible root cause is discussed in terms of the combined impact of stress induced by component and board warpage and the lower inherent strength of the solder joint near the melting and solidification temperatures.

In the past few years,several papers,test methods and methodologies have been developed to estimate pad cratering under Ball Grid Array (BGA) pads in Printed Circuit Board Assemblies (PCBAs).
However,almost all the tests and methodologies proposed so far have the following shortcomings:
1. They are destructive. The samples tested are broken and the failure mode(s) observed to determine the propensity for
cratering
2. They require testing several samples using different test methods (bend,shock,pull,shear or acoustic),but there is no easy correlation between the different test methods.
3. They can be used for relative comparisons,but there is no easy way to translate the correlations into failures in actual functional board level assemblies.
While these tests have helped mitigate pad cratering significantly,the industry still needs the following:
1. A non-destructive way to predict whether a certain PCBA design (BGA and PCB combination) is likely to result in mechanical strain induced pad cratering failures,long before the product has been built.
2. An easy to use way to correlate PCB level pad pull tests done per IPC-9708 and monotonic bend tests per IPC-9702,so that the design can be optimized to mitigate pad cratering failures during qualification testing.
3. An easy to implement design to detect pad cratering in a functional assembly,so that if a failure is observed in the field,it is easy to determine if the failure is due to pad cratering. Detecting a failure as soon as it occurs is critical in identifying the source of the mechanical strain that resulted in the failure,which in turn can help
quickly resolve the issue.
In this study,using extensive experimental data,a detailed methodology is outlined to show the relationship between board
strain,solder joint strain and force to failure in monotonic bend testing and pad pull testing. In addition,the correlation between monotonic bend testing and pad pull testing is shown,such that the results of pad pull testing can be used to estimate the likelihood of observing pad cratering failures in PCBAs during bend testing and manufacturing operations. The methodology can be used by designers to estimate the optimal combination of package and PCB design variables to minimize the likelihood of pad cratering and other solder joint failures during testing and field operation.
Finally,methodologies to predict and determine pad cratering failures quickly in field operations are also discussed and
outlined.

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