Pb-free Ball Grid Arrays (BGA) present unacceptable reliability risks for defense and space programs,but what are the options when SnPb devices are no longer available? BGA manufacturers express concern over the additional reflow cycles necessary for the reballing process. In addition,traditional re-balling processes for SnPb components requiring rework do not accomplish the complete flush of the existing alloy necessary prior to attaching new spheres. However,there is evidence that BGAs,as a rule,are very robust. Furthermore,an imminent industry specification,IEC/TS 62647-4,Process Management for Avionics –Aerospace and Defense Electronic Systems Containing Lead-Free Solder –Part 4: Ball grid array (BGA) Re-balling,provides guidance necessary to successfully convert Pb-free spheres to SnPb without thermal or mechanical damage. An examination of one BGA part type,reballed up to ten times,provides a view of IEC/TS 62647-4 type guidance and testing as well as the impact of multiple reballing attempts on the BGA. Barring another available specification for reballing,this specification was used for structure in this study

Growing material regulations compel electronics manufacturers to rethink product compliance. Can a company state with confidence every substance in the final product has been identified,and from where each item was sourced,by all direct and indirect suppliers? Consider the impact of the REACH,RoHS and Conflict Minerals regulations on the electronics industry. REACH protects human health and the environment through early and accurate identification of intrinsic properties within chemical substances. Companies must report all potential hazards,and then implement risk management measures. RoHS impacts all electronics manufactured or imported into the E.U.,regardless of whether the manufacturer intended the item for sale in region. Conflict Minerals requires companies to validate the sourcing of tin,tungsten,tantalum and gold (3TG) in products is not tied to vicious armed conflict in Africa. Electronics companies are challenged to verify the source materials came from conflict-free smelters. Companies must explore the greater complexity that spans the entire supply chain,including direct and indirect suppliers. As an article producer,each company is ultimately responsible for everything contained in the product. Simultaneously,companies must respect intellectual property,data accuracy and public perception,all within the changing compliance landscape. The End-of-Life Vehicle (ELV) legislation in the 1990s required the automotive industry to begin addressing the topic of material compliance reporting two decades before most other industries. The current solution employs data exchange standard,laboratory analysis,and supplier data communications to create a set of solutions that has proven effective. The company has been a partner with Automotive in developing and sustaining the approach,and is actively working with companies in other global industries. Lessons learned are shared from the successes and failures of our predecessors and industry partners,to aid the industry as we proceed together in today's complex regulatory environment.

One of the biggest challenges a corporate environmental compliance team faces is to collect complete and accurate material and substance data in a timely manner from suppliers. This paper will provide insight into some of the complexities involved in the logistics of supply chain data collection for RoHS,REACH,and Conflict Minerals. The paper will try to uncover why supply chain data collection is such a difficult task and propose some solutions (such as using industry standards like IPC-1752A) that companies can employ to make the process a little easier.

In 2012,The European Directive on Reduction of Hazardous Substances was recast. The new version of the directive now requires products to be adequately validated as RoHS compliant in order to be eligible for CE marking and access to the EU market. Additionally,the recast also increased due diligence requirements for companies validating their products as compliant,including elevated documentation,data validation,risk analysis,and record keeping requirements. Methods used to address RoHS compliance before this change,such as simply collecting RoHS compliance statements from suppliers,may no longer be adequate. This paper starts by reviewing the evolution of the RoHS directive and how it has evolved. It then moves on to cover the requirements and scope of the directive,as well as which standards are used to demonstrate compliance,and how those standards must be referenced in internal company quality processes. Suggestions on best practices for building a comprehensive,efficient,and effective product environmental compliance process with a focus on risk mitigation and cost containment are provided,including real world examples. New specific requirements for classifying parts and materials according to risk will be addressed,as well as new requirements to rank all part and material suppliers by evaluating the trustworthiness of the data they provide. Marking requirements,declaration of conformity formatting and examples,and technical compliance files,will be covered with examples provided. The EU REACH law is also addressed briefly. Although the REACH law is not tied to the RoHS directive or CE-Marking,REACH validation is required for access to the EU market,and compliance validation techniques can be similar to RoHS compliance validation. References to standards and industry resources are provided.

With increasing popularity and momentum for wearable and printed electronics,stretchable printed ink has become a hot subject for study and application. Circuitry printed from stretchable ink remains conductive even when it is elongated at a high percentage,thus it is useful for many wearable applications where stretching is required. There have been limited studies on stretchable ink and its stretchability. The characteristics of the stretchable ink and how different factors impact its stretchability are not well studied and therefore unknown. To accommodate the increasing demand for wearable applications,it is necessary to perform evaluations on the stretchable ink. This paper presents the company studies on stretchable printed ink. A test coupon is designed to prevent instability of connection between test probe and printed ink pad. Different design and test parameters are evaluated to shed light on how they affect the stretchability. The study is very useful to not only optimize the ink stretchability,but also provide insight on how to improve ink chemistry to enable more stretchability.

The rules of the game in PCB production are changing with new disruptive technologies. At the company there has been the implementation of a “primary image inkjet-resist” printer for both inner-layer print and etch and outer layer pattern plating processes in full production. Inkjet printing has become a crucial building block for the first zero emission,fully automated PCB factory. Ink jetting resist eliminates standard lithography processes while still providing a fully digital solution in a very small footprint. This technology combined with an intelligent nozzle conditioning routine,and real-time ink channel acoustic monitoring with double channel redundancy,gives full process control during production. To ensure higher yields and continuous feedback,the print is also fully inline scanned by integrated AOI at full process speed to check the print result before etching (Image Quality Inspection). The fully automated panel logistics,the clean machine,and reduction of processes enables CAM to etch processing within minutes. The short overall process pipe line and digital imaging gives flexibility to the flow and facilitates easy mixing of jobs. With “jet-resist”,production becomes a straight forward process,greatly reducing process steps and complexity compared to traditional production. Furthermore,since the resist is based upon a hot melt wax,the use of next generation etching and stripping process techniques have been employed that have resulted in 100% closed loop rinsing,stripping,and etching processes that consume no chemicals,and require no waste treatment whatsoever. The only by-products are solid resist and pure copper metal,which may be reused in the copper plater. Additionally,the precision of the ink placement on the substrate,further allows for a 5-10% increase in panel utilization compared with standard dry film and liquid resist application processes. The overall solution represents the next generation in PCB Fabrication,and a formula for manufacturing in North America and Europe at equal to or lower cost than current Asia-Pacific sources,in much shorter cycle times.

From photo film to digital camera,from letters to emails,from books to e-readers,from vinyl to MP3: the whole world is turning digital. Yet,ironically,the core compound driving the digitization of technologies and products is still being produced using analogue technology. Indeed,printed circuit boards (PCBs) are the beating heart of all digital “alternatives”,but the vast majority of PCBs are still produced using rotogravure print rolls,dry film or coated resists and phototool films. However,digital technology has become available to replace analogue imaging technology: inkjet printing is the digital alternative to the phototooling film process. Even though inkjet printing started off in merely marking/coding and document printing,it grew industrial in wide-format and billboard printing and is now mature enough for implementation in industrial production processes. The market of digital industrial product decoration is growing as we speak. Along with this,inkjet tools have been created for real high end industrial production. Inkjet technology based on UV-curable inks is especially ready for real production implementation. Besides the relatively well-known and readily adopted inks for legend printing on PCBs,UV-curable inkjet inks that are resistant to acidic etching and that can be stripped off in regular PCB production chemicals are now also available. The benefits of digital printing using these UV-curable etch resistant inks are clear and very relevant to PCB production: no time-consuming film production,no film exposure step,no development. With ink jet printing the images are generated on the fly and thus allow dynamic imaging. Since digital printing is an additive process,fewer raw materials are used,causing less waste. These UV curable inks are caustic strippable inks and are thus drop-in for present etch and strip lines. In this paper,the unique position of inkjet printing in PCB production will be highlighted and the chemical technology behind the inks will be explained in detail.

This experiment considers the reliability of a variety of different electronic components under isothermal aging and subsequent thermal cycling (TC) testing. The components are evaluated on 0.200” power computing printed circuit boards with OSP and a several different solder alloys. Single-sided assemblies were built separately for the Top-side and Bottom-side of the boards. This data is for boards on the FR4-06 substrate. Isothermal storage at high temperature was used to accelerate the aging of the assemblies. Aging Temperatures were25oC,50oC,and 75oC. Data from aging times of 0-Months (No Aging,baseline),12-Months,and 24-Monthswill be presented. Following isothermal aging,the assemblies were subjected to thermal cycles of -40°C to +125°C on a 120 minute thermal profile. The test was subject to JEDEC JESD22-A104-B standard high and low temperature test in a single-zone environmental chamber to assess the solder joint performance. The principal test components are 5 mm,6mm,13mm,15mm,17mm,31mm,35mm and 45 mm ball grid array (BGA) packages with solder ball pitch varying from 0.4 mm to 1.27 mm. Most of the BGA packages are plastic over-molded,while the 31mm and 45mm packages are Super-BGAs (SBGAs). Several surface mount resistors (SMRs) are also considered in order to understand the effect of solder paste composition on paste-only packages. The primary solder for package attachment in this experiment is standard SAC305,with SnPb eutectic comparison/baseline. Two alternative solders designed for high-temperature reliability are also considered.

The July 2006 implementation of ROHS exempted automotive applications from converting to lead free technology. Nine years later,all major OEM and Tier 1 automotive manufacturers have converted or are in the process of converting to lead free circuit assembly processing. Starting with SAC (SnAgCu) alloys as a baseline for lead free soldering,in the last years several specific alloys were developed in order to improve resistance to high temperature creep,vibration survival and the ability to withstand thermal cycling and thermal shock. The paper compares three different solder alloys and two flux chemistries in terms of void formation and mechanical / thermal fatigue properties. Void content and reliability data of the alloys will be presented and discussed in relation to the acceptance criteria of a Tier 1 /OEM automotive supplier. As a result,a ranking list will be presented considering the combined performance of the alloys. In order to analyze the void formation and mechanical behavior of different solder alloys and flux chemistry combinations,statistical methods are used.

IPC J-STD-001Fand IPC-A-610F require a minimum Heel Fillet Height (F) for Flat Gull Wing Leads of solder thickness (G) plus lead thickness (T) for Class 3 products.[1]It is shown in this work that this requirement prevents a solder joint geometry from being optimized for reliability especially under temperature cycling. Therefore,a reconsideration of the Class 3 criterion is proposed in this work. Temperature cycling tests in combination with finite element (FE) modeling have shown that there is an optimal solder volume to achieve optimum TCoB (temperature cycling on board) performance. On the one hand,increasing the solder volume beyond this optimum results in considerably more solder wetting of the pin shaft and thereby induces a stiffening effect on the gull wing lead. This effect results in higher stresses in the critical cross section area of the solder joint and thereby leads to a reduced solder joint lifetime in temperature cycling. On the other hand,reducing the solder volume results in a (too) small connection area and thereby reduces the solder joint lifetime. Balancing these two counteracting effects of solder volume on TCoB performance enables optimum product reliability. The current IPC Class 3 criterion in combination with process tolerances requires a nominal solder volume in design that is above the described optimum. Therefore a reduction of the minimum heel fillet height is proposed to enable a robust and optimum solder joint reliability for future products. It can be shown that the proposed change in solder joint design has a positive effect on product reliability concerning different loading conditions and failure modes as well.