The development of an automated circuit card assembly(CCA)conformal coating process using a low outgassing polyurethane material was essential for meeting the increase in customer demand from 3,000 to 60,000 units per year. Low outgassing polyurethane conformal coating is used for protection against humidity and tin whisker mitigation. When increasing production throughput requirements, it is necessary to eliminate variation and increase production capacity by automating processes.  Manual processes in manufacturing can lead to defects, increased variability, and additional manufacturing time.  To begin the process improvement of automating spraying a low outgassing polyurethane conformal coating, several machine and material parameters were considered during the evaluation.  A selective conformal coating machine was chosen, and the following parameters were determined to be critical to the process, thinner to material ratio, atomizing air pressure, material syringe pressure, nozzle distance from substrate, nozzle speed, material flow rate, number of coats, and curing requirements.  These parameters were verified by performing an adhesion by tape test per ASTM D3359-17, Standard Test Methods for Rating Adhesion by Tape Test, in addition to verifying conformal coat thickness and defects per J-STD-001, Joint Industry Standard Requirements for Soldered Electrical and Electronic Assemblies, requirements.  Implementing a selective polyurethane conformal coating spraying process has increased capacity capabilities and eliminated variations induced from the manual process.

Light-curable materials can provide significant benefits over conventional technologies, including lower operating costs driven by lower labor needs, space savings, lower energy demand, and higher throughput. A key advantage to light-curable conformal coatings is the ability to use a non-solvated “green”(100% solids) material. Conformal coatings are used to enhance long term reliability of automotive electronic parts.  Key properties include resistance to rapid and extreme temperature changes as well as protection against high heat-humidity, chemicals such as gasoline, and corrosive materials like salt and sulfur.  We have developed a light and moisture dual curable100% solids conformal coating that exhibits an excellent balance of properties. It is a light and moisture curable 100% solids conformal coating that exhibits premium performance.  Secondary moisture curing allows curing of the material under shadow areas helping to eliminate concerns about uncured material on the printed circuit board (PCB). We will discuss the performance of this material when compared to other light-curable materials as well as other chemistry types of conformal coatings, in reliability tests such as heat and humidity resistance (85 oC, 85 % relative humidity), thermal shock resistance (-55oC to +125oC) and corrosion resistance (flowers of sulfur, salt spray and common automotive fluids). Any changes in physical appearance including any formation of oxidation spots was assessed, and electrical insulation performance was recorded both before and after reliability testing.

To support regulations on hazardous substances in materials and in products like the automotive EU End of Life Vehicle (ELV) directive, the Electronics and Electrical Equipment Restriction of Hazardous Substances (RoHS) regulations and the EU Registration Evaluation Authorization and restriction of Chemical (REACH) regulation, industry sectors have defined and deployed various data exchange standards and cloud-based supplier portals to ease data collection in the supply chains and reduce burden in particular for small and medium enterprises (SME). In particular, the Electronics/Electrical sector has developed the IPC-1752 standard offering an XML data exchange format to support the EU RoHS. The automotive sector has put in place two major tools: The International Material Data System (IMDS) used by most of the car manufacturers and their suppliers globally, and the China Automotive Material Data System (CAMDS). The International Electrotechnical Committee (IEC) under TC111 responsibility has defined the IEC 62474 standard as a child of several existing standards including IPC-1752. Aerospace and defense with the heavy equipment industries have developed the new IPC-1754 standard in the IPC-175x series to support their specific requirements in particular to include process chemicals and declaration against any industry substance lists.

Industry sectors seems ready now to work on convergence to a unique material declaration standard covering data exchange for the above regulations for all product sectors. The “European Proactive Alliance” was launched in 2018 March/May; it is an initiative to establish such a unique data exchange standard for reporting “Substances in Articles”. The IEC 62474 standard, the IPC-1752Aand IPC-1754 standards (or aharmonizedIPC-175xseries)are the candidates for this journey.

This paper presents the set of requirements that the standard(s)would have to support in the coming years to become the global one for a large set of sectors, including automotive, chemicals, furniture, childcare products, electrical and electronic, mechanical, metalworking and metal articles, home textiles, textiles and sporting goods as well as medical devices. Several options are presented and would have to be discussed with all the stakeholders in the coming months and years.

There are multiple purposes for this paper: i) socializing and promoting use of data exchange standards in all sectors at any level of the supply chain for a more accurate reporting of hazardous substances and materials in products for a better world; ii) identifying existing issues and coming challenges and proposing possible solutions to fix them for more effective reporting; iii) proposing a long term perspective and plan to align all the stakeholders including the legal authorities for providing to business an efficient reporting system. 

Such a plan includes: a new governance model more global and less North American-centric; a process-based approach to specify all support activities for related pieces of the standards like XML schemas, guidance documents; a harmonization of the IPC-175x standards series; an enhanced development process inspired by ISO and IEC best practices. Another condition of success would also be to continue convergence between the IPC-175x and the IEC 62474 standard selected by many global companies and Japan. This is a new challenge that the IPC organization and the IPC-175x committees will have to meet in the medium term.

This paper has been written to address a large industry audience per its purposes. It is first of all an educational paper that provides to any business representative a simplified state of the art of the data exchange formats as standards covering substances and materials reporting in products and used in their processes. It also includes a review of existing issues and new challenges shared with end-users of the standards and companies represented by their trade associations, with some solution proposals they could discuss. Finally, it proposes to prioritize the required changes to the standards with a long-term perspective for all stakeholders(Standard Development Organization sand their committees, legal authorities in charge of regulatory lists and their data)to review, discuss, share and include them or not in their strategic business plans.

Until recently, virtually all restricted materials in electronics were classified as either carcinogens (e.g. Pb) or reproductive toxins (e.g. phthalates). Two new categories of restricted materials have emerged -endocrine disrupting chemicals (EDCs) and persistent organic pollutants (POP). These two new categories of restricted materials will bring into regulation chemicals that have not historically been restricted. This significant increase in material at risk of substance regulation is expected to change the design and procurement landscape in a way not seen in the electronics industry since the original EU RoHS Directive.

The High Density Packaging (HDP) User Group has completed a project based upon an earlier project evaluating the different types of high frequency test methods used in the industry for measuring Dk and Df at high frequencies. This paper will present the important results of evaluating the effect of copper surface roughness and topography on high frequency loss using several high frequency test methods, particularly to determine whether there are any differences in loss along the X-axis versus the Y-axis. These test methods included the VNA, high speed Stripline and SPP high frequency test methods. The earlier test vehicle was modified including varying the geometry of the line widths to increase the sensitivity of the testing. The following test conditions were run using the same low loss laminate materialandthesametreatmentpriortopresslaminationforeachtestmethod;HighResinContentwith two different line widths along the X-axis versus Y-axis, Low Resin Content with two different line widths along the X-axis versus Y-axis. The measured differences in high frequency loss were found to less than anticipated, with some variation depending upon the high frequency test method used.

Earlier HDP User Group project work that has been completed and published compared the different types of high frequency test methods used in the industry for measuring Dk and Df at high frequencies. The HDP project test results being reported on in this paper are based upon that earlier work. This paper will mention but not discuss in detail a weight gain testing protocol that has been developed for driving and controlling higher levels of moisture content within a board. This paper does present the important results of evaluating the effect of moisture content on each of the high frequency test methods using a variety of laminate materials. These test methods include the Z-Direction, Trace-Conductor and In-Plane types of high frequency test methods. Both standard and halogen-free laminate materials were evaluated inthe low loss, middle loss, and higher loss ranges. The following four conditions were tested for each laminate material and test method; As-Received, After 30C/85% RH for 168 hours, After 85C/85% RH for 168 hours, Baked-Dry. The measured differences in moisture content were found to contribute up to a 43 percent difference in the measured Df or Loss values, depending upon the high frequency test method used and the laminate material.

As electronic assembly designs have increased in density and component packaging size and lead pitch have decreased in size, this has placed tighter requirements on manufacturing processes. Tolerances there were considered insignificant in the past are now critical to high yield, reliable products.

With the increased rate of technology advancement, industry standards, material limitations and assembly processes have lagged in response to these changes.

This slide show presents solutions to the relevant Power Module question: "What has to be considered within a PCB, if currents with about 50 A and voltages above 500 V should be designed?"  The electrical and thermo-mechanical capabilities are critical constraints.  2D and 3D CAD models can be utilized to predict creepage and clearance gaps.  Thermal imaging can be used to see  thermal management properties of the Power module functioning under operating conditions.  Tests must be run to ensure that the high currents don't create creep, and the insulation reliably prevents shorts. 

The operation and reliability of any electronic assembly is very dependent on the performance, quality and consistency of the bare printed circuit board (PCB). Without good quality bare boards then, however professional the assembly process, whole batches of product will beat risk of failure, as they will have been built on an inherently bad foundation. Often bare board issues are identified much later in the root cause analysis procedure as the assembler will typically focus first on examining and clearing what they (may) have done before looking at the component parts. Therefore, appreciating how bare boards are manufactured, understanding the potential areas for failure and having access to appropriate inspection facilities should allow, in principle, those involved with Goods Received, or at the first step of the assembly process, to identify and minimise bare board issues ahead of their release into assembly manufacture.

Any external bare board problems may be identified simply with optical inspection techniques. However, if the issue lies within the board, then this will not be optically visible. Such issues include plating thickness variation, poor drilling quality, imperfect through-hole formation, micro-via consistence variation, internal track reduction and poor pad and hole alignment. Looking inside the board to check if these issues occur could be achieved by taking micro-sections. However, this is a destructive, time-consuming and expensive process that requires expert interpretation and is limited to analysing very small sample areas. This makes micro-sectioning uneconomic and unrealistic to do, not only for a typically low value component in high volume manufacture such as the bare board, but also if the bare boards are very few in number and of very high price. Therefore, the use of non-destructive techniques is preferred. This is where X-ray inspection facilities, more typically used for analysing assembled boards, can also be used to identify bare board issues. This paper will illustrate and explain how using 2D and 3D X-ray techniques can show many of the problems described above.