Review Winter Conference 2019 – 14th & 15th February
At the EIPC Winter Conference in Milan on February 14–15, as the EIPC Chairman, I opened the first day of the conference in the customary style by welcoming sponsors and guests. Noting that it was Valentine’s day as well as the 150th anniversary of Mendeleev’s periodic table, I made a special Valentine’s day version of the table complete with heart-shaped elements. I went on to explain that 2019 was the International Year of the Periodic Table of Chemical Elements to mark Mendeleev’s achievement in categorising the element in groups defined by their atomic mass and valency.
I further explained that Mendeleev’s insight allowed him to infer the existence of as yet undiscovered elements and even to predict their properties. Mendeleev had postulated that “ekaaluminium” must exist in the gap in his table immediately below aluminium; we now know this as gallium, and his forecasts of its properties were spot on. I produced some of the soft, silvery blue metal gallium, explaining that it has a melting point of less than body temperature so that it would melt in your hand. Some delegates tested this to find it was indeed true, and despite warnings, many left with gallium-stained hands!
Moving back to the periodic table, I moved on to the alkali metal series, particularly lithium, which has an atomic weight of around seven and is responsible for the naming of the once lithiated drink “7-UP.” However, lithium is now better known for batteries, and my presentation swung, as it often does, towards automotive electronics. I discussed the energy density of different fuels and postulated that a hydrogen fuel cell/lithium battery hybrid vehicle may provide a good compromise of properties in the near future. I ended as I started with a special version of the periodic table. This time, the table produced by the European Chemical Society showed the elements relative to their availability. Many elements that we rely on have limited availability, which poses a future supply risk.
EIPC conference delegates are accustomed to hearing from industry sage and elder statesman Walt Custer in the first keynote presentation. But Walt is suffering an ongoing mobility issue, so he entrusted me to deliver the keynote on his behalf. My presentation began with the words, “Brace yourself for some sobering news.” I explained that due to significant geopolitical concerns, such as inflation, tariffs, trade disputes, and Brexit, global manufacturing growth is slowing, and most sectors of the world electronic supply chain were now expanding more slowly or even contracting.
Data showed that European electronics sectors, except instruments, medical electronics, and aerospace, declined in 4Q’18. Walt’s customary detailed analysis and reasoning followed, ending with my conclusion that we should expect slowing growth, especially in Europe, with trade disputes impacting long-standing regional alliances, causing electronic assembly to shift globally to countries less affected by tariffs. However, there was good news in that there are many new electronic products on the horizon, and 5G will offer exciting opportunities for the next decade.
Erkko Helminen of TTM Technologies delivered the next presentation. Helminen took the delegates through the 5G roadmap for PCB producers, detailing the impact of shrinking geometries, lower noise budget, complexity, tightening tolerances, and the lower total loss budget, showing how each element could be addressed to meet the new demands. He also described future self-driving electric vehicles as data centres on wheels that may require up to 1,000 chips per vehicle by 2020 and create a data requirement of up to 4,000 GB per day. The new technologies required covered not only new materials and process technologies but also environmental aspects as OEMs are expected to be more active in pushing supply chain efforts on environmental sustainability. Helminen’s presentation ended with a thought-provoking slide showing near-future PCB technology drivers and the many challenges that need to be overcome in their delivery.
The next session on new trends for the imaging of PCBs, conductors, and solder mask was moderated by Tarja Rapala-Virtanen, EIPC’s new technical director.
The first presentation by our hosts, Elga Europe, was delivered by Ilaria Pasquali and focussed on the development of a new dry film resist (DFR) with high sensitivity and high pattern definition working with new laser direct imaging (LDI) systems.
Pasquali explained that new requirements for tighter tolerances allied with high production capacity had rapidly increased the need for LDI capabilities with a reliable dry film resist. LDI machines require not only a more sensitive DFR but also one suited to the precise wavelength of the imaging laser which could be 405 nm or 375 nm. Moreover, by reformulating the DFR photoinitiator system, Elga had produced a wide portfolio of DFRs that allowed high productivity and high definition with high adhesion performance for the latest generation of LDI machines.
Next to present was Uwe Altmann of Orbotech who spoke about solder mask direct imaging. Altmann began by detailing the development of direct imaging technologies from the late 1990s to the present-day Orbotech Diamond machine. The presentation showcased the benefits of speed, low print energies, accuracy, robustness, and low operational costs. Altmann also explained that the imaging technology used three UV wavelengths—365, 385, and 405 nm—to match the wide variety of solder resist materials available. The presentation concluded with a description of integration within the smart factory whereby the imaging system can access part-specific data “on the fly” to minimise setup time and maximise accuracy and traceability.
Hironori Takashima of MEC Europe was next up on the importance of reducing metal etching in surface treatment profiles for lamination and solder mask printing. Takashima showed conventional technologies for roughening copper and explained that with the reduction in copper trace width, chemical etching becomes more significant. This, allied with the requirement of lower profiles to reduce transmission loss at higher frequencies, prompted the development of new surface treatments offering a low etching amount while still retaining high adhesion. Takashima also explained the etching mechanism of the new MECetchBOND CZ-LE process for build-up material lamination and solder mask printing by reference to the preferential attack on grain boundaries over crystals, leading to a unique copper surface topography. The presentation continued with the spray-applied BO-LE process copper surface roughening solution as an alternative for black oxide treatments. Takashima ended by showing impressive transmission loss and adhesion data for the new treatments.
Nicolas Falletto of ESI next took the delegates through a comparative analysis of multiple laser sources for cutting/ablation efficacy and quality on HDI PCB and ICP. Falletto explained that there were three application areas where laser cutting was becoming of increasing interest: laminate cutting, routing/singulation, and die cutting. Then, he showed experimental results from three laser sources using both single-line and multi-pass strategies. Falletto concluded that the quasi-continuous wave laser source demonstrated the fastest process speed with an acceptable quality edge after cleaning, and that multi-pass processes produced the lowest carbonization. Future work will include testing other laser sources and quality control as a function of the size and the density of parts in the panel to process.
Talking to a blue screen due to technical issues for the start of his presentation, Don Monn of Taiyo America took the delegates through recent developments with inkjet solder mask, starting with the question, “What does your solder mask need to do?” Then, Monn proceeded to deliver an animated talk, discussing features, such as CSP pads and solder mask-defined pads, and showing examples of isolated traces, gang traces, and 3- and 5-mil dams. He also reminded delegates of his predictions from 2015 of how dams would look. Monn ended his presentation with an explanation of how the viscosity versus temperature curve was crucial for performance and demonstrated the IPC-SM-840E, Class H and T—solder mask vendor testing requirements.
The next paper presentation by Andreas Schatz of Atotech Electronics Equipment focussed on automation and green manufacturing. Schatz explained the benefits of automation under the headings of quality control, process outcome, operator friendliness, safety and sustainability, water reduction, and chemical consumption. He went on to show a case study of an automated PCB batch handling system using recipe management via extensible markup language (XML) to set all related production parameters automatically. Schatz described the factory of the future as one where the workpiece and machine are intelligent and completely networked so that they autonomously manage production. Also, Schatz explained that Atotech’s Fab 4.0 solutions help realize the factory of the future today through secure a communication interface and intelligent usage of process data.
The morning session ended with Chudy Nwachukwu of ITEQ whose paper entitled “Specifying PCB Materials for HSD and MM Wave System Performance” discussed the main technology drivers and dielectric challenges to satisfy “the need for speed.” Nwachukwu explained that the requirements for high-speed digital (HSD) and radio-frequency (RF) millimetre wave designs were, in many cases, moving in the same direction with system designs trending towards single-board solutions combining both functions. The material properties of thermal robustness matched dimensional shrinkage and CTE, and mechanical stability was highlighted as being critically important in addressing hybrid RF and HSD complexity. Nwachukwu also demonstrated the similarity of desired PCB material attributes for RF and HSD designs and concluded by postulating that high-Tg thermoset resin systems may present the most effective combination for high layer count hybrid PCBs offering improved reliability at low cost.
After lunch, EIPC Vice Chairman and PragoBoard s.r.o. CEO Oldrich Simek moderated the next session on “New Advanced Materials for Future Electronics.”
Then, I returned but in my role as technology ambassador for Ventec International Group. I began by outlining the automotive application “hot spots” requiring thermal management and described LED lighting and its advantages, such as lower power consumption and long lifetime. I also outlined Haitz’s law, how the cost per lumen fell by a factor of 10 per decade, and how the amount of light generated per package increased by a factor of 20 for a given wavelength.
Next, I introduced basic thermodynamics and detailed the principles of the first, second, third, and “zeroth” laws describing the principles of heat transfer and convection, conduction, and radiation in the context of LED thermal management. I referred to the thermal conductivities of a range of well-known materials and equations relating to convective and radiative heat transfer along with an example calculation model for thermal radiation. I also illustrated the importance of being able to survive thermal cycling (e.g., in a headlamp unit) through the use of two case studies where failure had occurred. Failure analysis showed that the CTE mismatch between various materials used in the construction had been the likely cause. I concluded by showing how the issue was resolved by using materials with more closely matched CTEs and by optimising moduli.
Sven Johannsen of Dyconex spoke next on the topic of liquid crystal polymer (LCP) for hermetically-sealed sensing applications. The presentation concerned medical implants and Johannsen explained that LCP materials offered advantages over state-of-the-art implants, which currently use a titanium can. The main advantages of LCP substrates were that they are thin (
The last paper of a busy day was presented by Roland Schönholz of Technolam on the topic of high-frequency CCL materials for automotive radar applications. First, Schönholz went over automotive electronics trends, including Internet of vehicles (IoV/5G), advanced driver-assistance systems (ADAS), and new energy.
Next, he included an informative video of an interaction between an irate user and an intransigent automated vehicle much to the amusement of the delegates.
Schönholz continued his presentation with an overview of emerging industry requirements for automotive radar communication and analysis of the material properties required. He discussed an example 77-GHz hybrid automotive radar, which is a mixture of millimetre-wave materials and high-Tg FR4 materials, along with new materials solutions to satisfy the requirements—especially the stability of dielectric constant (Dk) and dissipation factor (Df) under severe climate conditions.
After the papers of Day 1 the delegates were hosted at a reception and plant tour of Elga Europe at their nearby production facility. IMAGE 3. Georgio Favini, CEO, explained that Elga was founded in 1973 and had had three important joint ventures in its history, firstly with Lea Ronal then Tokyo Ohka and currently with Eternal. Favini explained that Elga Europe is the European leader in dry film photoresist for PCB fabrication being the only remaining European producer and having a capacity of 15 million Sqm/Year.
The dry film production process was then described in detail and the delegates were treated to a comprehensive plant tour seeing all the stages of manufacturing through mixing, coating, drying, in-line inspection, testing and slitting. The delegates were very appreciative of the hospitality shown by Elga Europe and felt privileged to have been shown around such an impressive facility by such knowledgeable staff.
The delegates then went back to downtown Milan for a gastronomic dinner in the very chic deli/restaurant “Eataly”.
Suitably refreshed after the excellent networking dinner the delegates took their places for day 2 of the programme.
The opening session entitled “New developments in PCB Technology, DFM and Cost Effective Supply Chain management” was chaired by EIPC Board Member Michele Stampanoni, Michele Stampanoni.jpg who introduced the first speaker Robrecht Belis of Elsyca. Belis introduced a PCB plating performance simulation system allowing plating layer thickness distribution prognosis before the start of production. Belis explained that the PCB plating process is very sensitive to panel size, pattern, holes, plating infrastructure and the electrolyte. The system developed characterises the plating process using infrastructure and electrolyte data and then utilises the specific circuit design to build a simulation of plating distribution. Belis went on to describe how design modifications, copper balancing and layout optimisation can then be performed prior to production starting. Belis concluded with a case study carried out at EuroCircuits where he demonstrated the resulting optimised layout, time savings and better quality deposition uniformity over manual techniques.
Roland Valentini of Gardien Group was next to present on the topic of “The Impact on supply chain management, final PCB yield and profitability”. Valentini started his presentation from the premise that there had been a major change in the Industry from analogue to digital and that this had brought new challenges for manufacturing and test. He further argued that traceability is going to be one of the key requirements to fulfil in high reliance markets, identifying the sectors as automotive, space, aerospace and military, medical, industrial, network and 5G base stations, mobile communications and home automation. Valentini went on to describe the Gardien managed supply chain process whereby the supply chain between the purchasing manager and the PCB fabricator is kept as lean as possible with non-added value steps being eliminated. The presentation concluded with a Chinese PCB sourcing example with the potential to effectively double the number of potential PCB suppliers and a description of the Gardien test service to the PCB industry to improve quality, reliability and total productivity.
The last paper of the session was presented by Markku Markku Jämsä of Aspocomp. The topic of the presentation was “Thermal Management in PCBs, Options for Designers” and took the delegates on an interesting journey through different methods of PCB cooling, focussing on thermal vias, metal back and embedded copper coin techniques. Jämsä then proceeded to show examples of the technologies before sharing detailed benchmark data of the various options showing advantages and disadvantages of each. The presentation closed with a glimpse of possible future cooling possibilities including mechanically drilled copper filled thermal vias, high conductivity coin materials (>>>500 W/mK), 3D printed complex embedded cooling elements and active cooling.
The last session of the conference “New soldering Technology, Quality assurance and Durability testing” was chaired by EIPC Board Member John Fix of Taiyo America. The first paper entitled “The current state of the Solder Limits” was presented by Crystal VanderPan of UL, US. Crystal Vanderpan.jpg. Vanderpan started with an explanation of the UL PCB Program background and explained that the purpose of the program was to reduce risk. Solder Limits were explained as reflecting the maximum temperatures and times of the assembly soldering process and defined as any component assembly time spent over 100°C or MOT (Maximum Operating Temperature), whichever is greater. It was noted that Solder Limits can be a single time and temperature or multiple times and temperatures (Multiple Solder Limits – MSL) and that solder limits do not apply if hand soldering. Vanderpan went on to explain that Solder Limits are a critical parameter for the PCB and are characterized as part of the recognition process with thermal stress testing used for evaluation of solder limits. The presentation continued with the information that traditional solder float test is not representative of SMT solder operations and that three standard reflow profiles are available to test, namely T230C, T245C and T260C and that collaboration between OEM, assembler and PCB fab continues to find the most appropriate standardized solder limits/assembly profile. Vanderpan summarised saying that solder limits represent the soldering process the PCB is exposed to during component assembly, that the term solder limits can be changed to assembly profile and that PCBs tested with multiple solder limits diminish the risks to end product consumers.
Next the conference to welcomed Robert Boguski of Datest, US, whose paper was entitled “New Developments in Digital Computed Tomography (CT) for Nondestructive Failure Analysis of PCBFs and PCBAs”. Boguski began by contrasting two-dimensional x-ray projection images with two-dimensional vertical-slice computed tomography (CT) images explaining that through CT data reconstruction spatial dimensions of all features can be calculated and digitally rendered into a true volume representation. This representation can then be visualised as the entire volume or an individual sliced view of interest. He further explained that the X-ray penetration information in 3D space is divided into small cube units, voxel pixels, the value of each element being a function of the chemical composition and density of the material in the element; consequently, each small cube is full of features such as defects, boundaries and material properties. Boguski explained Datest’s 225kV microfocus CT setup and showed some very impressive visualisations of objects as diverse as a tangerine, a hard drive and an electric screwdriver. It was of course, however, the detailed visualisation of PCB and PCBA features that most interested and impressed the audience. The presentation concluded with a summary that CT can be a useful inspection technique and that NDT (Non-Destructive Testing) will be integral to the next evolution of manufacturing technologies, in PCB manufacturing as well as many other industries
Dr. Lei Wang of Heraeus Deutschland spoke next on the topic of the Development of a High Reliability No Clean Solder Paste. The presentation began by describing the cleaning of solder paste residues as a complicated and high cost process, the motivation of the development was therefore to find a no-clean solution overcoming traditional concerns of future reliability risk. Wang went on to describe the technical challenge of using an activator to enable wetting whilst not making the assembly susceptible to later SIR (Surface Insulation Resistance) failures explaining that finding the appropriate balance was the key to success. The results of the newly developed DP3 solder paste were presented for a variety of surface finishes and processes, all demonstrating good results. The presentation ended with a summary of reliability, solderability and workability data.
Next the delegates heard from Michiel de Monchy of MacDermid-Alpha whose paper was entitled “Principles of Silver sintering and the importance of PCB finishes”. De Monchy began by explaining the principles of silver sintering, describing it as a process of atomic diffusion whereby at a temperature below the melting point, the atoms in the powder particles diffuse across the boundaries of the particles, fusing the particles together and creating one solid piece. The advantages as an alternative to soldering as a die attach were described as superior electrical and thermal conductivity and therefore higher reliability, the demand for which was being fuelled by growth in electromobility – silver was described as the ideal die attach solution. The Alpha® Argomax® – Advanced Bonding Technology Based on Silver Sintering process was then described in detail along with results obtained with a variety of surface finishes. De Monchy concluded with a prediction that silver sintering as a die attach finish to the substrate will grow significantly in the near future.
The last paper of the conference was presented by Hermann Reischer of Polar Instruments, Austria whose presentation was entitled “New automated Controlled Impedance Tester”. Reischer began with a comprehensive explanation of the need for controlled impedance testing and a detailed description of test methods and procedures. The case for increasing test volumes, tighter tolerances, improved gauge R&R, unattended testing and the elimination of human influence on measurement was then made with reference also to improved traceability. Reischer further explained the design challenges presented with developing an automated test solution and described the development of a rotating differential probe head that was able to adapt to different test coupon formats whilst applying a constant probe pressure. The presentation closed with an impressive visual demonstration of the automated test equipment utilising a custom-built tray containing 30 test coupons.
After the closing panel discussion I brought the conference to a close commenting on how delighted I was as a metallurgist to have had so much high quality content in my field of expertise. I thanked the sponsors, with a special mention of Elga Europe for their kind hospitality, the session chairs, the speakers and EIPC Technical Director Tarja Rapala and the programme team for their excellent and valuable contributions to the conference. Sincere thanks were also given to EIPC Executive Director Kirsten Smit-Westenberg and EIPC Project Manager Carol Pelzers for their diligent and detailed attention to detail ensuring our continued success. I noted that our much-loved reporter and journalist Pete Starkey was “hors de combat” after a fall earlier in the week and wished him well for a speedy and full recovery. In closing I invited the delegates to join us for the next EIPC conference to be held in Leoben, Austria June 13 & 14 which will include a factory visit to AT&S.