Very low viscosity formulations are often required for very thin conformal coating applications. Solvents are used to reduce viscosity of the formulations and accommodate dispensing needs. Solvent-free coatings are attractive due to their environmental friendliness and ability to allow faster processing for coating lines. Until recently,efforts in developing very low viscosity 100% solids coatings were not successful due to performance requirements such as chemical,heat,and humidity resistance. We have developed a technology that results in 20-30 cP viscosity 100% solids UV curable coatings. We will discuss the performance in reliability tests such as heat and humidity resistance (500 hours at 85 oC / 85 % relative humidity) and corrosion resistance (flowers of sulfur resistance and salt spray resistance). Any change in physical appearance,formation of oxidation spots,and insulation performance were checked after reliability tests. The new coatings can also be cured with long wave length LED light and secondary heat.

A new hybrid ALD/CVD protective coating is being considered as a low-cost alternative to poly-para-xylylene and traditional liquid conformal coatings. All of the typical conformal coatings protect the printed circuit boards. This relatively new process is a hybrid atomic layer deposition (ALD) / chemical vapor deposition (CVD) process that produces a unique and very uniform thin film coating. This film offers improved protective properties compared to the other materials such as poly-para-xylylene and the liquid coatings. Plus,the material may have the added improvement that the costly process of masking components is normally not required. The hybrid coating process is carried out in a small-footprint platform and can process PCBs in a large batch. Results will be shown that demonstrate excellent performance results as tested to standard IPC-TM-650 testing protocols,and an opportunity for a new technology that represents an improvement over traditional conformal coatings and poly-para-xylylene.

Security has become a vital part of electronic products as they handle sensitive data in uncontrolled environments and as they face more and more content protection issues. The paper will introduce the security challenges for smart systems and describe a new security tool box and smart packaging which can be obtained by introducing 3D Nano-materials printed envelope (several meters electrical performance with spacing capability of 50 µm),3D embedded devices into electronic modules (active die in PCB) and multi-die WLP System in Package,with active anti-tamper sensors as well as the combination of all,focusing on both the security performance assessment as well as the manufacturing process.

The electronics industry trend continues to be to continually increase capability and performance within an existing or smaller footprint. Shoehorning all of the required components onto the exterior surface of the PCB has become an increasingly difficult puzzle. The use of stacked microvias instead of plated through holes and stacked ICs in various configurations has freed up some real estate. The use of ever smaller passive devices also saves space,but reintroduces old issues such as tombstoning. The ideal solution would be to provide ‘surface’ real estate within the architecture of the circuit board –like moving items from a desk to a bookshelf –by embedding components into the board. Leveraging the established buried TLPS (Transient Liquid Phase Sintering)paste microvia technology for z-axis interconnection,“via layers” with TLPS paste inserted into lamination adhesive at the desired interconnect points to the component terminals could be used to connect to embedded components. Ideally,components could be buried at any layer to maximize topside real estate and minimize wiring lengths. The concept of using TLPS-filled via layers to make both connections to buried components and any other z-axis interconnections required on any layer will be explored. The combination of the sintering paste interconnect and an interposer element is the key to enabling this architecture. This manufacturing strategy presents a number of advantages. The board may be broken down into logical substructures such as high density,core or RF portions. Each of the sub-PCBs can be fabricated according to best manufacturing practices for that portion of the circuit board rather than trying to fabricate a single complicated board. Yield losses from sequential process steps and multiple laminations may be reduced. The component placement can facilitate point-of-source architecture for high electrical performance. The process flow and laboratory demonstrations of this technique will be presented in this paper.

More and more people and things are using electronic devices to communicate. Subsequently,many electronic products,in particular mobile base stations and core network nodes,need to handle enormous amounts of data per second. One important link in this communication chain is high speed press fit connectors that are often used to connect mother boards and back planes in core network nodes. These new high speed press fit connectors have several hundreds of thin,short and weak pins that are prone to damage. Small variations in via hole dimensions or hole plating thickness affect the connections; if the holes are too small,the pins may be bent or permanently deformed and if the holes are too large they will not form gas tight connections. The goal of this project was to understand how rework of these new high speed press fit connectors affects connection strengths,hole wall deformations and plating cracks.

There are times when a PCB prototype needs to be built quickly to test out a design. In such cases where it is known early on that there will be multiple iterations or that a “one and done” assembly will be made that there will be some SMT assemblers who choose to hand print solder paste onto the board using a “frameless” stencil. In such cases where hand printing is used,the consistency of the printing technique has typically been in question. Furthermore,the effectiveness of both the nanocoatings as well as the higher end stainless steel materials,which have been heretofore studied in controlled printing environments,will be evaluated for their impact on the hand printing process.

Rising customer demands in the field of PCB repair are a daily occurrence as the rapid electronic industry follows new trends in a blink of an eye. New strategies and technologies are required to fulfill those demands. Out of the long list of today’s customer demands for efficient BTC and SMT PCB repair some subjects show up on a daily basis and are agreed to be relevant for the coming years:
• BTC types with new effects -> voidless treatment
• Smaller components -> miniaturization (01005 capability)
• Large board handling -> dynamic preheating for large board repair
• Repeatable processes -> flux and paste application (Dip and Print),residual solder removal (scavenging),dispensing,multiple component handling,and traceability
• Operator support -> higher automation,software guidance (Human Computer Interface)
• Cost effectiveness -> Rework Systems for different budgets and ROI situations

Automating electronics assembly is complex because many devices are not manufactured on a scale that justifies the cost of setting up robotic systems,which need frequent readjustments as models change. Moreover,robots are only appropriate for a limited part of assembly because small,intricate devices are particularly difficult for them to assemble. Therefore,assembly line designers must minimize operational and readjustment costs by determining the optimal assignment of tasks and resources for workstations. Several research studies address task assignment issues,most of them dealing with robot costs as fixed amount,ignoring operational costs. In real factories,the cost of human resources is constant,whereas robot costs increase with uptime. Thus,human workload must be as large and robot workload as small as possible for the given number of humans and robots. We propose a new task assignment method that establishes a workload balancing that meet precedence and further constraints. The following must be determined before using our method: which tasks robots can perform,and which workstations robots are assigned to. We assume that humans can perform every task and consider the constraints that restrict the tasks robots can perform. By applying our method to several case studies,problems involving 20humans were solved within 1minute and 1% dispersion. These results indicate that our method can be used in actual factories where a short-term planning period corresponding to frequent production fluctuations is required. We also applied our method to real assembly data for laptops manufactured by our company and obtained task assignment that reduces the operational costs by 30%. This suggests that our method can contribute to promoting the automation of electronics assembly by demonstrating its cost reduction potential.

Choosing an outsourced manufacturing partner that is perfect for a new product and close to your design team is quite different to choosing a partner that can manufacture that same product in volume in lower cost locations and fulfil globally. This is where the Gateway model comes into its own. Most large EMS have structured their organizations to leverage proximity to OEM design teams in high cost regions while providing the benefits of low cost regions for volume manufacturing. The “Gateway” facility in higher cost regions provides design engineering,supply chain design,prototype,and NPI services. The goal of the Gateway is to develop an effective build recipe that can then be effectively and seamlessly transferred to one or more volume manufacturing facility that offers lower costs and direct fulfillment to consumers. We will present a case study that highlights the value of this model and that shows some of the key elements that allow for seamless transitions from plant to plant. The Gateway model is an essential element to a successful global manufacturing model and helps ensure that products are made in the right geography.

As the demand for higher routing density and transfer speed increases,Via-In-Pad Plated Over (VIPPO)has become more common on high-end telecommunications products. The interactions of VIPPO with other features used on a PCB such as the traditional dog-bone pad design could induce solder joints to separate during the second and thereafter reflows. The failure has been successfully reproduced,and the typical failure signature of a joint separation has been summarized [1].To better understand the solder separation mechanism,this study focuses on designing a test vehicle to address the following three perspectives: PCB material properties,specifically the Z-direction or out-of-plane Coefficient of Thermal Expansion (CTE); PCB thickness and back drill depth; and quantification of the driving force magnitude beyond which the separation is due to occur. The test vehicle is designed such that each VIPPO pad is surrounded by dog-bone via pads and each of the VIPPO joints has independent daisy chain for in-situ monitoring during the second reflow cycle. There are four different pad designs: all VIPPO design; VIPPO and dog-bone mixed pad design; VIPPO and skip via mixed pad design; and back-drilled VIPPO mixed pad design. The all VIPPO design is the baseline benchmark. The VIPPO and dog-bone mixed pad design is expected to be the worst case scenario. The VIPPO and skip via mixed pad design together with the VIPPO and back-drilled VIPPO mixed design are included to narrow the magnitude of inherent build-in stress induced by the CTE mismatch which causes the VIPPO joints to separate during the second reflow. The test vehicles are fabricated with two different PCB materials. Material A is a traditional high-end PCB material with high Z-direction (out-of-plane) CTE; while Material B has approximately one third of the Z-direction CTE of Material A.A Design of Experiment(DoE)with two PCB materials (Material A and Material B) and two PCB thicknesses(93mil and 125mil) has been performed. With the designed single-ball daisy chain test vehicle and installed thermocouples,the correlation between electrical continuity (daisy chain resistance) and solder joint temperature (thermocouple) can be derived. A video was taken of two cross-sectioned samples during the second reflow cycle using a reflow simulator. The observation is consistent with the findings of the test vehicle (TV)for in-situ monitoring. The results also provide more accurate and broader information for the investigation on why,how,and when the solder separation occurred during the second reflow cycle.