The beautiful city of Leoben in central Austria provided the setting for the EIPC 2019 Summer Conference, and what a summer; the mercury hit the mid-thirties (in Celsius, of course)! It was no coincidence that we found ourselves in Leoben, as everyone knows this is the location of one of the world’s leading PCB technology companies—AT&S—and we were proud to have them as a sponsor and have the opportunity to visit their world-class manufacturing plant nearby.
I was privileged to make the welcome address and chose artificial intelligence (AI) as my theme. After welcoming the delegates and thanking those who had kindly sponsored the event, I demonstrated how the power and availability of graphics processing units (GPUs) had transformed image processing with a live example of facial recognition software and how realistic “deep fake” videos can be produced from only a few frames of a real subject. I took the bold move to demonstrate some AI features of my DJI Mavic Air drone by controlling it solely with hand gestures. Luckily, no delegates were harmed in the demonstration!
I concluded with drone footage of the demise of my first drone where I crashed it into a tree after the system foolishly handed control back to me during a “return to home” AI function. I was reminded of the fact that in over 30 years of operation, there have only been two crashes recorded on the automated London Docklands Light Railway (DLR), and that both of those crashes occurred when the system was operating under human control!
We were then honoured by the presence of Daniel Geiger, the vice-mayor of Leoben who extended a very warm welcome to the packed conference room. He emphasised the importance of advanced manufacturing technology in Europe—a point that resonated well with the audience.
The first keynote presentation was prepared by Walt Custer. Due to mobility issues, Custer was unable to attend in person, so it was my pleasure to give the presentation on his behalf. The format of Custer’s business outlook presentation is well-known and appreciated by regular EIPC conference attendees.
This time, the outlook was not particularly rosy with global manufacturing growth slowing based on purchasing managers index (PMI) data showing that most sectors of the world electronic supply chain are now expanding slower or contracting. Tariffs, trade disputes, and Brexit/EU were identified as key issues with geopolitical concerns remaining very significant. Military spending, perhaps not unexpectedly, showed a worldwide increase in 1Q '19 vs. 1Q '18. And in Europe, there were increases for aerospace along with electronic components and loaded boards, which may be indicative of some stock building in mitigation of the effects of trade disputes and impending Brexit.
Custer’s charts showed double-digit percentage reductions in both semiconductor production and semiconductor capital equipment investment, which means we can expect further contraction for some time down the supply chain. The prognosis for 2019 vs. 2018 PCB worldwide production showed a contraction of 0.9% but with some large regional differences. Germany showed the highest contraction of 5.5% after recording growth of 3.5% in 2018 vs. 2017.
The next keynote was delivered by Gerald Weis from the Advanced Packaging department at AT&S. Gerald chose design for excellence (DFX) related to embedded components as his topic. His informative presentation described a design-based approach for PCBs that entailed a wide range of defined rules, processes, and standards focused on optimizing the product realization life cycle. Weis took the delegates through the entire process, starting with defining what is meant by embedding before describing the various issues that might arise. He concluded that DFX is a complex topic requiring the use of intelligent interchange formats during the development process and that interfaces between design, simulation, and development are essential to achieve the benefits of increased volume utilization and lowered parasitic impedances achievable by embedding.
The next session covering supply chain and reliability was moderated by EIPC Technical Director Tarja Rapala. Tarja welcomed Gardien Group’s Roland Valentini to take the podium. Valentini explained that the goal of his presentation was to help delegates get a better understanding about how their supply chain could be improved to optimise delivery time, reduce communication issues, and receive only pretested PCBs, all at the lowest possible cost. He highlighted that whilst US$5.9B of PCB are needed in Europe, only about US$2.0B are produced.
Further, Valentini argued that to support this approximately US$4B supply-chain gap and the two-thirds of required imported populated PCBs, new and advanced supply-chain tools and control functions are needed. He went on to describe the details of a framework for advanced supply-chain management meeting and exceeding customers’ performance requirements whilst increasing PCBA production yields by reducing defect rates, minimising risks, and decreasing costs. A key feature of Gardien’s solution was described as an independent but integrated on-site test and inspection function participating in continuous improvement activities; focused quality control reduces rework and enables full transparency of actual fabrication yields.
Next, conference attendees heard from Paul Carré of Polar Instruments who addressed the issue of maximising repeatability of impedance measurement. Carré began with a resumé of his career at Polar Instruments and some fascinating information on his interest in sharks—yes, sharks! Then, he explained that USB4 allows for a maximum data rate of 40 Gbps and is expected to roll out in 2021, which is driving the need for maximising repeatability. Carré described the test setup as having two TDR-based test systems: a 35-pS Tektronix DSA8300 and an ~250-pS Polar controlled impedance test system (CITS). He showed TDR traces for a 75-ohm test vehicle over 6, 4, 3, or 2 inches and 1 inch as well as clearly demonstrating the difficulty of stable measurement on the short trace lengths. Carré summarized that entry quality and perturbations are key and that faster rise time is no guarantee of short trace measurement capability.
The first part of the session concluded with a paper prepared by Frank van den Bosch of Ucamco, which was presented by André Bodegom of Adeon Technologies BV. The presentation covered direct imaging (DI) applications and began with a look at the development of DI technology from 2005 to the present day. Bodegom described the features of the Ledia 6 System, which utilises a broad multi-wavelength optical system ranging from 350–440 nm to diffuse the energy optimally throughout the resist or solder mask.
The Ledia 6 System allows users to finetune each wavelength’s power individually for optimal results on or each material. Examples of the results were shown with 50-µm solder mask dams without undercut. Bodegom described further details of the autofocus, image-head calibration, and alignment system for registration accuracy. Next, he explained Ledia’s Dynamic Process Format (DPF) Interface for Serialization and Image Stamping (DISI) System for generating on-the-fly board serialization and variable image stamps at the time of exposure as a method to ensure unique PCB identification and traceability. The presentation closed with an overview of automation options for inner and outer layers and solder mask.
After a short coffee break, the session continued with Jan Pedersen of Elmatica presenting on how a broker’s communication can solve technical issues. He started with an overview of Elmatica from its founding in 1971 to its position today as a digital supply chain partner. Pedersen displayed a chart mapping required knowledge of processes and technologies, showing the positioning of the customer and two example PCB factories where the broker was able to bridge the technical knowledge of the PCB factories whilst exceeding the process knowledge of the customer. Through three case studies, he demonstrated how communication and process knowledge solved the issues of via opens and bow and twist and offered a depth-milled semi-flex solution. I was delighted and proud to have been named as the person who suggested the depth-milling solution to Elmatica! Pedersen closed with words from one customer: “With your involvement, we always find a solution and end up with delivery.”
Next, we heard from EIPC Vice President Emma Hudson of Gen3 Systems who delivered her paper “Ionic Contamination: So, What Has Changed?” She explained why we should care about ionic contamination and described the pros and cons of common ionic contamination test methods. Then, Hudson addressed how the introduction of IPC J-STD-001G Amendment 1 had replaced the 1.56 μg/cm2 of NaCl equivalency requirement, which was established in the 1970s, with an objective evidence requirement to qualify that the contamination left on the PCBA is acceptable and monitor that qualified contamination levels are not exceeded during production. So far, so good.
However, Hudson then pointed out that other IPC requirements, such as the IPC-6012 Automotive Addendum, still include a 1.56 μg/cm2 of NaCl equivalence before solder mask application. The IPC-6012DA-WAM1 Automotive Applications Addendum to IPC-6012D also has a 0.75 μg/cm2 of NaCl equivalence before solder mask application with no scientific justification for the number selected—just that it’s “better” than 1.56 μg/cm2. Despite the inconsistencies arising, Hudson argued the merits of the new approach and described the process by which objective evidence is obtained before concluding that PCB manufacturers should expect to start hearing more about this from their customers as the changes come down the supply chain.
The last paper of the session, “From PCB to Assembly: Performance of New Coatings Applied Along the Production Chain,” was delivered by Sven Kramer of Peters. Following an introduction to the Peters Group, Kramer focussed on liquid photoimageable solder mask (LPISM), coatings supporting effective thermal management, and protective/conformal coatings for enhancing reliability and lifespan. He showed that the application methods of LPISM have regional differences leading to challenges in compliance with a specified maximum thickness on the top of tracks and a specified minimum thickness at the track corners.
Then, Kramer showed a combination of a printed heatsink and a printed thermal interface paste were used to level surface roughness, displace air, and thereby create an optimum connection to the cooling element to support heat transfer and heat dissipation from the assembly side to the cooling side. He also covered conformal coatings which are used to enhance reliability and lifespan.
Further, Kramer showed differences between micro-encapsulation and conformal-film/coat, along with various stress factors affecting electronic assemblies. He ended with the message that successfully working in the field of high-end coatings for electronics requires considerably more effort and investment in technology than ever before.
After lunch, EIPC Board Member Michele Stampanoni of Cicor Group introduced the next session on “New Material and Coating Technologies.” Steve Woods of Sun Chemical presented the first paper of the session and covered developments in advanced LPISM for high-temperature and DI applications. He also described the development of a solder mask designed to meet the higher temperature thermal cycling tests for the automotive industry.
The development process utilised variants of existing resin technology whilst maintaining pigment levels/colour density of standard solder mask in producing a product that could be applied by screen print, curtain coat, and spray methods and that was suitable for exposure on DI and conventional exposure light sources. The thermal cycling requirements of two automotive Tier 1 suppliers were described and the test results of the most stringent of these being 2,000 cycles of a 15-minute dwell time. In addition, Woods demonstrated that the product developed was able to meet the requirement without failures (40°C to +170°C). He continued by showing positive test results for moisture and insulation resistance and electrochemical corrosion as well. His final remarks emphasised that laminate selection and ink film thickness control were critical for success.
Frank Louwet of Agfa-Gevaert took the podium next to present his paper “Be Flexible, Go Digital: Deeper Insights into the Benefits of Inkjet Solder Mask for PCB Production.” After an introduction to Agfa-Gevaert, he charted the development of ink application technologies from screen printing to laser DI and additive inkjet printing. Louwet emphasised the importance of 100% additive and digital technologies with the key benefits of printing solder mask only where necessary leading to cost-efficient solder mask deposition, no solder mask in vias, prevention of solder bridges between closely spaced solder pads (dam printing), resistance against electrical breakdown, and solder mask thickness.
Louwet also demonstrated the reduction in process steps by using inkjet for solder mask application and the significant reduction in the process ecological footprint compared to conventional technologies. He described how variable thickness, coverage and jetting performances, and surface quality are achieved before detailing the physical and electrical requirements. Louwet concluded with a summary of inkjet benefits, including solder mask being applied in the amount needed only on the desired areas and the high reliability and excellent jetting performance while meeting today’s demanding PCB requirements.
Staying with the inkjet printing theme, but this time from the equipment side, the next speaker was Joost Valeton of Meyer Burger NV. First, he introduced Meyer Burger as a leading global technology company specializing in innovative systems and processes. Valeton showed the various industries where inkjet systems are used before focusing on PCB technologies and the benefits of being environmentally friendly by reducing process steps along with waste and material usage.
Valeton then described the equipment solutions offered by Meyer Burger and explained that the key features of software integration and small drop size from the printheads (2.5 pL) plus drop flow-out compensation and advanced resolution control for accurate feature size produced the highest quality solder mask printing. He showed visual examples contrasting performance with other systems. Valeton ended with the technical details that 50-μm line/space features are achievable and that experience shows a >96% availability and printing of up to 60 sides/hour.
Continuing with the inkjet theme, the conference wouldn’t be complete without hearing from Don Monn of Taiyo who didn’t disappoint with his presentation on white solder mask for automotive applications. He started with an estimate of the automotive lighting market value, which was US$25.7B in 2016 and will rise to US$35.9B by 2022. Then, Monn explained the requirement for white solder mask in automotive lighting with details of the stringent specifications for gloss, reflectance, and colour stability after thermal ageing. He also addressed the challenges of producing a highly opaque material that had high-enough photosensitivity to offer a wide process window.
Monn went on to explain that cracking is more prevalent in white solder mask than standard green solder mask during assembly and the reasons behind this before introducing Taiyo’s new white solder mask, which was specifically designed to reduce the challenges of cracking and photosensitivity without compromising other essential properties. In addition to the general requirements, Monn shared additional specifications for ionic contamination, hot storage, and solvent resistance along with the test results for the Taiyo product showing that all requirements were fully achieved.
Closing the session and the first day of the conference was David Bernard of David Bernard Consultancy, whose presentation was entitled “Bare Board Inspection: Ensuring a Sound Foundation for Assembly.” He began by explaining how PCB assemblers had long used X-ray inspection techniques driven by the need to inspect optically hidden joints. X-ray systems offering high-magnification, high-resolution imaging provided top-down and oblique angle views. Considering the difficulties faced in checking bare boards before assembly, Bernard introduced the concept of using the PCB assembler’s existing X-ray equipment to provide quick, non-destructive tests on representative samples of bare boards.
To demonstrate this concept, Bernard showed oblique X-ray images with impressive examples of poor drilling quality, layer misalignment, plating failure, and cracks. Moving on from the 2D examples, he showed partial computed tomography (PCT) images where the benefits of reconstructed 2D X-ray slices at different levels in the Z-direction with a decluttered image allowing individual layers to be analysed were readily apparent. Bernard described the PCT technique as being able to be undertaken anywhere on the board non-destructively, whilst full CT, which is destructive, requires a small volume (like that used for micro-section) to enable high-magnification/high-resolution 3D models. Bernard concluded by stating that there is a place for all of the described techniques and suggested that they are used in this order: 2D views, then PCT, full CT, and micro-section.
Tour and Dinner
Before departing for the bonus programme visit to AT&S, Jürgen Deutschmann gave an informative presentation. He explained that although AT&S is headquartered in Austria, it operates six manufacturing plants in Europe and Asia with 10,000 employees. In addition to being among the top 10 PCB producers worldwide, AT&S also holds the third position globally in high-end technology. Deutschmann then identified R&D as the key for technological leadership and informed the audience that over 40% of revenue is generated with products that had new and innovative technologies introduced to the market within the last three years.
After a safety briefing, AT&S hosted a tour of its Leoben facility, which was impeccably clean, well-organised, and highly automated. Delegates were highly impressed at the level of technology in the plant and professionalism that was shown by the AT&S guides and were very grateful for their kind hospitality.
Following the AT&S tour, the delegates were invited for dinner at Gösserbräu in Leoben where the EIPC staff were, once again, surprised to find that a brewery made an excellent networking venue. The beer and food were excellent, but I most highly appreciated the quality of the company. Daniel Geiger graciously joined us for dinner and very kindly requisitioned some local buses to take us back to the hotel.
Look for Part 2 of this coverage coming soon.
Technical editor’s note: I most gratefully acknowledge the support of EIPC Chairman Alun Morgan for preparing this review and providing the photographs. Many thanks! —Pete Starkey