One of the most perplexing phenomena in the electronic manufacturing industry today is the defect called “head-in-pillow.”
Head-in-Pillow (HnP) defects occur on the blind solder joints of area array packages such as FBGAs,µBGAs and CSPs. Often these insufficient or intermittent solder joint defects go undetected during manufacturing despite inspection with conventional X-ray systems. They also are insidious reliability defects that often escape the normal testing procedures and fail at the end user site. The head-in-pillow defects typically occur at the corner pins and outer rows of packages and are associated with package warpage. There are new 3D imaging systems that can help detect this,but they rely on the operator to interpret the images. There are BGA video inspection systems that can view under most devices,depending on the standoff,but they are dependent on the access,viewing angle,and operator interpretation. These x-ray and video processes also are very slow and costly.
There are several factors that can contribute to the head-in-pillow phenomena including package co-planarity,package warpage,and assembly issues associated with solder paste characteristics and stencil printing. From a process standpoint,the cause of the head-in-pillow often is the result of the sum of all of the component and assembly process tolerances. This paper will discuss several contributing factors to the head-in-pillow defects and techniques to control them. It will include reviewing DOE for solder paste deposition of five different pastes,Shadow Moiré scans on several problematic devices,cross-section analysis of failed solder joints,and solder paste analysis of “head-in-pillow” pastes. The case studies presented show that process control can mitigate HnP defects but may not be successful for some severe examples of HnP defects.
This paper uses components from telecommunication product case studies to demonstrate the effects of different contributing factors and mitigation techniques for HnP defects. The case studies include reviewing solder paste printing modifications,solder paste DOE,Shadow Moiré scans on several problematic BGA packages,effectiveness of x-ray inspection,and crosssection analysis of failed HnP solder joints. Together,these case studies show that BGA package warpage is a major contributor,but HnP defects can occur when almost any of the assembly process parameters deviate from acceptable practices.

One of the effects of the ever increasing mountain of regulatory requirements and the globalization of markets is the need to
disseminate and collect information across the shop floor and the enterprise in either real or near real time. Companies are finding that a paper environment does not provide the nimbleness needed to execute today’s adaptive business models which are required in a rapidly changing economy.
Fortunately,a variety of process and information technologies have emerged and intersected to provide economical solutions for today’s process management and product traceability needs. Electronic process trees and instructions can be used as
collaborative information portals providing a wide range of capabilities. By strategically applying measured amounts of
technology to achieve the operational nimbleness needed,a company can stay relevant in what is becoming a rapid globalization of markets and regulations.

“Unprecedented” is a word often used to describe the events caused by the economic downturn and its impact on the
automotive electronics industry. The result has been numerous plant closings and plant product portfolio realignments throughout the industry. This paper focuses on how to effectively carry out production line/facility transitions from one manufacturing location to another.
The first part of this paper focuses on how a company’s systems,structures and strategies provide the basis for successful
production relocations. Manufacturing Technology Teams (MTTs) are strategic structures within Delphi Electronics & Safety
Manufacturing Engineering. These are virtual organizations which network a group of engineering professionals for the interest of technical contribution. The teams are chartered to design and implement common manufacturing systems and process building blocks around the globe. By having the same design standards,equipment sets,process setups and training,moving a production line from Milwaukee,Wisconsin,to Mexico,for example,is more a logistic challenge rather than a technical issue. Strong foundations such as these allowed Delphi Electronics & Safety to conduct over seventy transition projects over an eighteen month period with no customer disruptions.
The second part of this paper covers the mechanics of carrying out production transitions. Particular attention will be paid to
the creation of a standard transition template for enterprise-wide use to create achievement plans. Next,the importance of a
management steering team will be considered. The charter of such a team is to track progress of all projects,provide a venue for escalation and resolution of problems,and provide a Communication vehicle for issues of common interest to all transition teams. The importance of customer communications,both external and internal,will also be stressed. Other often
overlooked,but no less critical,topics are covered in this paper such as conducting in-depth workshops at sending sites to uncover “hidden factories,” the adjustment of supplier contracts especially when changing legal entities,understanding and agreeing to validation requirements and freezing product and process changes during the moves.

Large printed wiring assemblies (PWB) exceeding 7000 circuit nets create significant quality,cycle time and cost issues at structural test in the new product introduction (NPI) phase. Traditional in-circuit test and its requirement for expensive bed-of-nails (BoN) fixtures impose high tooling costs and long cycle times. While flying probers (FP) do not require test fixtures,thereby reducing those cost and time impediments,testing large board imposes extremely long test time and lower test coverage. We describe a “Flexible Fixturing System” which overcomes the cost and tooling cycle times inherent with traditional BoN fixtures while simultaneously providing the high throughput rates and test coverage of traditional in-circuit testers. Moreover,this is accomplished at an attractive capital cost.

This paper discusses the benefits and limitations of universal,low-pin count Automated Test Equipment for Printed Circuit
Assembly (PCA) testing utilizing the test access port (TAP) defined in IEEE Std. 1149.1. The test equipment under
consideration allows the application of a wide variety of JTAG/Boundary Scan connectivity and pseudo functional tests,ideal
for use as a desktop test system for prototype verification and production test. In particular,we will present ways of creating
test applications that utilize embedded test resources in the Unit Under Test (UUT) and tester channels provided by the ATE
in a compact and all-inclusive fashion. The paper will also discuss overall cost of test reductions achievable with such test
equipment.

RoHS exempt high reliability OEMs breathed a sign of relief for not having to go through the grind of revising their processes and material to be RoHS compliant. However,this was short lived because of supply chain disconnects in the availability of non-RoHS devices. Consumption,in terms of unit volume for Sn/Pb,is small compared to the volume going into the builds of Pb free consumer and commercial product. Many device manufacturers are discontinuing the Sn/Pb option on many part numbers (P/N) when unit volumes fall below a certain threshold.
Bills of materials are being transitioned to obsolete and legacy parts outside the control of the OEMs and at a rapid pace. The
life cycle for a military product generally takes over two years for the design and initial deployment,followed by a production life cycle of over 10 years and a repair/warranty cycle of 20 plus years. A redesign to include an alternate part number is no easy task due to redesign review,validation and reliability testing.
In addition,exempt OEMs are exposed to other problems caused by some manufacturers not changing P/Ns once the Sn/Pb is
obsolete. The end result too often is mixed reels of RoHS and non-RoHS product. Unfortunately,exempt OEMs are many
times left with only one choice and that is Pb-free components. This is clearly not optimal due to some of the reliability
concerns associated with Pb-free components. Reflow profiles,thermal stress,MSL,tin whiskers,tin pests,brittleness,voids
and thermal mismatch are some of the reliability problems that can’t be ignored and can’t be managed in the absence of the
specific Sn/Pb component.

Since the electronics industry moved to lead-free solders that typically have a tin content of more than 95% there has been
concern about the possibility of circuit malfunctions due to whisker growth. It is now generally accepted that whisker growth is a response to compressive stress within the tin crystal and the challenge is to identify and eliminate or at least minimize the
processes that can generate such stress. Corrosion has been identified as one source of that stress and in this paper the
authors report a study directed at identifying the relationship between the extent of corrosion and the concomitant whisker
growth. Printed circuit coupons with an OSP finish were soldered with SAC305 solder using wave,reflow,and hand soldering methods with flux formulations typical of current commercial practice. These coupons,soldered but without components,were exposed to three environments for up to 3000 hours: 40°C/95%RH,60°C/90%RH and 85°C/85%RH. As well as recording the location of whiskers,their density,and length as a function of time,the extent of corrosion of the solder after 1000,2000 and 3000 hours was measured by cross-sectioning. The ultimate determinant of whether or not whiskers appeared was the environment to which the test pieces were exposed. The highest incidence (whiskers per unit area),fastest growth rate,and greatest length occurred on test pieces exposed to 85°C/85% RH. Whiskers occurred later,at a lower
incidence,and grew more slowly at 60°C/95% RH but even after 3000 hours no whiskers were detected on test pieces exposed to 40°C/95% RH. The incidence and growth rate of whiskers was found to vary with the soldering method and the type of flux. Whisker growth occurred earliest on the test pieces that had been wave soldered. Geometry was found to have an effect with the concavity created on the edges of traces by the etching process apparently acting to focus the compressive stress and accelerate whisker growth in that area. The authors relate these trends in whisker growth to observations of the concurrent corrosion of the solder which in turn is related to the type of flux used. A preliminary conclusion is that the likelihood of whisker growth occurring on lead-free assemblies soldered using no-clean technologies can be significantly reduced by using a flux which does not promote the sort of corrosion that can generate compressive stress in the solder.

The objective of this study is to evaluate conformal coatings for mitigation of tin whisker growth. The conformal coatings chosen for the experiment are acrylic,polyurethane and parylene. The coatings were applied in thicknesses ranging from 0.5 to 3.0 mils on 198 bright tin plated coupons with a base metal of either Copper C110 or Alloy 42. Prior to coating,light scratches were applied to a portion of the coupons,and a second fraction of the coupons were bent at 45° angles to provide sources of stress thought to be a possible initiating factor in tin whisker growth. The coupons have been subjected to an environment of 50°C with 50% relative humidity for over five years. Throughout the trial period,the samples were inspected by both optical and scanning electron microscopy for tin whisker formation and penetration out of the coatings by tin whiskers. Tin whiskers were observed on each coupon included in the test,with stressed regions of the bent samples demonstrating significantly higher tin whisker densities. In addition,the Alloy 42 base metal samples showed greater tin
whisker densities than the Copper C110 base metal samples. There were no observable instances of tin whisker penetration out of the coatings or tenting of the conformal coat materials for any of the non-stressed test coupons. The stressed coupons demonstrated tin whisker protrusion of the 1.0mil thick acrylic and polyurethane coatings for the Alloy 42 base metal samples. The greater thickness coatings (minimum of 2.0mils) did not demonstrate tenting or tin whisker protrusion. This paper will also include materials properties of the conformal coatings examined along with appropriate processing techniques in order to better understand the role of the coatings in tin whisker mitigation.

Counterfeiting is clearly a growing problem in many industries,including electronics,around the world. As the financial impact of counterfeiting has grown over the years,so has the attention that has been devoted to it by everyone from packaging,assembly,and test engineers to procurement and quality personnel. Today,many feel that counterfeiting is the number one issue that threatens the electronics supply chain.

•Background information
•Scope of the problem
–Anecdotal
–Study by International Chamber of Commerce
–Recent study US Dept of Commerce
•What to do about it ?
–“Findings” and “Best Practices”
•Types of strategies