EIPC Summer Conference 2022: Day 1 Review
At last, a live EIPC conference and this time in the Swedish city of Örebro, “where history and contemporary culture converge,” a pleasant and convenient location for an event that included a privileged visit to the Ericsson facility in Kumla. Around 100 delegates made the journey and the Örebro Scandic Grand Hotel was an excellent conference venue for the June 14-15 conference.
EIPC president Alun Morgan welcomed all and was delighted to report that EIPC had gained 10 new members in 2022.
With his natural flair for looking at situations from imaginative perspectives, Morgan cited Jorge Luis Borges in his reference to the latest developments in supercomputers and artificial intelligence. Borges’ story, “The Library of Babel,” effectively exposed the absurd futility of humanity's attempt to understand everything when there is an almost infinite amount to comprehend. Exascale computing would enable the identification of new patterns in data, and the development of innovative data analysis methods to accelerate the pace of scientific discovery. Regrettably, in the meaningful words of English humorist and satirist Sir Terry Pratchett, “Real stupidity beats artificial intelligence every time.”
The opening conference session, moderated by EIPC technical director Tarja Rapala-Virtanen, was the keynote on market outlook and new business opportunities. It has become a tradition for the event to begin with an analysis by Custer Consulting. Walt is enjoying his retirement, and his son, Jon Custer-Topai, has taken the reins and had compiled a comprehensive update. Jon could not attend, but his presentation was ably delivered by Morgan.
Summarising the first quarter of 2022, Custer commented that the initial optimism has not lasted long because the Russian war with Ukraine has caused a fragile supply chain to worsen again. Particular challenges for semiconductor manufacturers are that Ukraine supplies 50% of the world’s semiconductor-grade neon, and Russia provides the United States with more than a third of its palladium. Prices continue to rise in the whole supply chain due to cost increases for raw materials, shipping materials and labour. The price of copper has increased, and fuel and energy prices are soaring. World Bank forecasts for real rates of economic growth in 2022 indicate a world figure of 4.1%; U.S., 3.5%; Eurozone, 4.4%; and China, 5.6%
In 2021, Germany manufactured 43% of Europe’s PCB production, with a value of 709 million euro. Austria and Switzerland, 19.6%; Italy, 11.7%; and UK 8.5%
Custer acknowledged the contribution of Michael Gasch, who forecast that, based on sales results for the first four months in 2022, the total potential growth in Europe could be between 7% and 9%, with Germany, Austria, and Switzerland having between 6% and 7%. The German speaking countries are strong in automotive, medical, and industrial electronics, whereas France, Belgium, Spain, and Italy are mainly active in aeronautics and defence. He expects total PCB sales in Europe to reach more than 1750 million euro.
Gasch warned that there could be some “nasty surprises,” depending on developments in the Russia-Ukraine conflict, the progress of COVID and when Chinese factories will be able to manufacture again. Further factors include the dispersal of the clogged harbours in China together with the normalisation at the harbours in the U.S. and Europe, the availability of shipping containers at the places where they are needed, the availability of components from China and other Asian countries, the availability of materials needed for laminate and PCB production, and finally, the development of consumer behaviour as inflation reduced their spending power. Because of the complexity of the situation, the eventual outcome could be totally different.
A second insight into the business and technology of the printed circuit industry came from Dr. Shiuh-Kao Chiang, managing partner at Prismark Partners. From his comments, it is clear that 2022 will be an interesting year and does not appear particularly friendly for the PCB business.
Reflecting upon the first quarter’s results in 2022, he remarked: “The electronics industry is in the late stages of a historic cycle fuelled by the COVID-19 pandemic, but cracks are now forming at the edges. No party lasts forever.” The current forecast was for modest growth, with factors like inflation, high interest rates, a strong U.S. dollar, the Ukraine conflict, and China’s zero-COVID policy to be taken into account.
He summarised the main challenges to the electronics industry as high inventory along the supply chain, weak demand due to declining purchasing power, high inflation and high interest rates, over-supply of rigid and flexible boards, geopolitical conflicts causing high energy costs, pandemic lockdowns causing disruptions in supply-side production and logistics, as well as labour shortages and material cost volatility.
He believes that the strongest segments will be industrial and medical, automotive, computing, and communications infrastructure and other consumer electronics, particularly wearables.
The substrate market is experiencing continued growth; around 14% is expected in 2022. HDI products will be required in more non-consumer applications, such as automotive, high-performance computers, high-speed networking, and satellite communications—although a weak smartphone market could impede HDI growth. More low-loss multilayer boards will be required for infrastructure. The automotive market will demand more high-reliability high-current and high-thermal circuit boards, and there will be a decline in orders for rigid boards for consumer and PC applications.
Although the first quarter of 2022 has been strong as a consequence of carry-over from 2021, indications are that the industry will have a relatively weak second quarter. The current consensus for the third quarter is that there will still be some inventory issues to resolve. There will be price erosion due to competition and over-supply. Maybe a rebound will happen in the fourth quarter? In Chiang’s opinion the forward visibility remaines unclear and it is difficult to make accurate projections.
Chiang had some words of warning for European PCB manufacturers: “Be cautious about your competition. Your competitors in China are growing. They are expanding their market share and continue to upgrade their technical capability.”
His closing comments: 2022 will be an interesting year after the glory days of 2021, with many challenges to be confronted. His suggested approach is to aim to maintain relative stability in managing a business and to work toward finding the best solution to deal with a couple of those challenges at a time.
Morgan moderated the second conference session, discussing the technology roadmap and its associated technical requirements.
EIPC board member Stig Källman, component engineer PCB at Ericsson Örebro, shared his vision and offered invaluable technical guidance and practical recommendation in his talk on setting the PCB trends and requirements for 6G PCB manufacturing.
He considers that making tomorrow’s designs with yesterday’s equipment, but capability matched, is the best way to create value and make profit. Emphasising the benefits of re-use and standardisation, his examples of standardised building blocks are Lego bricks and shipping containers. He recommends using cost-efficient layer stackups and via structures, avoiding over-design by understanding manufacturing variation, and achieving high manufacturing-panel utilisation.
He discussed PCB technology drivers: smaller lines, spaces and via sizes, high speed serial links, low-loss materials, high supply currents, optical waveguides in PCBs, and thermal management. He considered the impact of manufacturing on the environment, referencing energy efficiency, and the avoidance of hazardous substances.
Regarding laminates, he said, “Making a good soup we need the right recipes,” and regarding stackup options, he pleaded, “Don’t give us so many options! Teach us how to use the standard builds that are most produced with best tolerances to the lowest cost.” It was Ericsson´s ambition to phase out halogenated flame retardants in its products, with decisions made on a case-by-case basis, based on valid parameters, and the availability of environmentally sound alternatives.
To meet the challenges of current and future PCB technologies, Kallman’s laminate wish-list included low-Dk (less than 3) low-loss for high impedance, high-frequency RF, high-Dk (greater than 10) low-loss for low impedance, high-frequency RF, and magnetodielectric materials with a different balance between electric permittivity and magnetic permeability depending on the RF application. He sees it as important that the datasheets of halogen-free materials list their full mechanical properties, as well as data for the resin, including any fillers, covering the temperature range from -40°C to +220°C.
Discussing future material possibilities along the development path toward 6G, his view on resin development is that it should include three-way collaboration among the OEM, the material supplier, and the PCB supplier. He has a similar view on defining and measuring critical PCB design parameters that it should involve designer, manufacturer, and laminate supplier in equal proportions. And in new product introductions it is very important to ensure that the PCB shop has the opportunity to run production tests and be supported with manufacturing guidelines before any customer test boards were made.
Robrecht Belis, head of sales and PCB related business at Elsyca in Belgium, recommended a “shift-left” approach to the optimisation of bare board design, in order to identify and fix problems as early as possible in the development cycle.
As a specialist in the simulation of the PCB electroplating process, he discussed how multi-physics digital twin solutions could contribute to the optimisation of costs, product quality, time to market, and production capacity.
Quoting leading designer Rick Hartley, “Copper balancing should be done, not only at the panel level in PCB fab, but every PCB designer should be taught the many benefits of copper balancing and incorporate the concepts into their board designs.” Belis showed real examples of the significant variation in plating thickness of unbalanced designs and how thickness distribution can be optimised using proprietary software tools.
He cited testimonials confirming how the software has helped to identify critical areas at the design stage, to support engineers on the shop floor in predicting how different set-ups of designs and parameters influenced the outcome, and to accurately predict the plating parameters required to enable increased first-pass yields on new parts.
Stan Heltzel, materials engineer with the European Space Agency, described ESA’s approach to microvia reliability.
Describing PCBs as the nerves and veins of the spacecraft, he introduced the ESA web portal: European Space Components Information Exchange System, of which the PCB section (escies.org/pcb/) gives details of ESA Approved Manufacturers and Qualification Status of PCBs, ESA Qualification Status of PCB technology, ESA Approved PCB Manufacturers, ECSS standards for design of PCBs (ECSS-Q-ST-70-12C), and qualification and procurement of PCBs (ECSS-Q-ST-70-60C), as well as listing active ESA memos and checklists, historic ESA memos, and technology development and conference papers.
At the bottom of a long list of active ESA memos and checklists was ESA-TECMSP-TN-19672 Microvia Process Guidelines which gives a general process overview and specific process recommendations for laser drilling, pre-etch and cleaning, desmear, microetch, rinse, electroless copper and copper electroplating, as well as tests for qualification, lot conformance and in-process verification.
The document can also be used as a guideline for conducting a process audit. The guidelines have been drafted with support from PCB experts and experts from chemistry suppliers, and have been reviewed by the PCB manufacturers of the PCB/SMT working group.
Heltzel reviewed technology drivers: electrical performance, manufacturability, and reliability, with reliability depending on design, materials and processes, and manufacturability depending on capability and qualification. He demonstrated technology development with the example of the Apollo guidance computer of 1969 compared with a contemporary smart phone which was a million times more powerful, weighed a hundred times less and cost a thousand times less.
Introducing the HDI roadmap using a series of cross-section diagrams, he discussed the confidence interval of stress-strength analysis, failure life cycles, and microvia failure mechanisms. The approaches used by ESA to evaluate microvia designs were a review of the design with comparison to heritage and qualification, thermo-mechanical modelling, testing coupons and spare PCBs, and review of manufacturing processes. He described ESA’s procedures for Manufacturing Readiness Reviews for PCBs, which culminated in authorisation to proceed with manufacture, and discussed details of thermo-mechanical modelling, causes of strain on microvias, and microvia qualification and conformance testing.
There is work in progress using a standardised test panel in a round-robin campaign for high-reliability industry, which will provide a robust assessment of capability and reliability, secure the HDI supply chain, and validate several test methods.
It had been concluded that microvias can be used reliably, through review of design considering all critical features, and compared against a qualified envelope of technology features, with manufacturing processes optimised through mutual assessment among the supply chain. Compliance is demonstrated by test and inspection and qualification, loT conformance, in-process verification, and capability assessment.
“Stop resistance clouding your high-speed measurements,” said EIPC board member Martyn Gaudion, CEO of Polar Instruments, explaining why the distributed series resistance has to be removed from the measurement to make an accurate impedance measurement. He used 50 ohm coaxial cable to illustrate his point, different lengths of cable all having nominally the same impedance value. Impedance controlled PCB traces were, in effect, simulated coaxial cables in PCBs, so why were some PCB fabricators under the illusion that impedance changed with length? The reason was that, in fine line designs, DC resistance could cause inaccuracies in impedance measurement.
Gaudion illustrated graphically the effects of distributed series resistance and distributed shunt conductance. Distributed series resistance make the impedance appear to rise with length and it is necessary to remove its effect in order to achieve an accurate impedance measurement. Otherwise, it could be wrongly inferred that datasheet dielectric constants are incorrect.
To check whether series resistance was clouding the measurement, he suggested modelling the resistance and simulating the effect on a TDR trace by entering the trace geometry and the line length and seeing the expected result on the TDR waveform. In contrast, on broader line widths, the resistive effect could be safely ignored.
But if the DC resistance effect is ignored on fine-line traces, the TDR reading would be high compared with predictions. This could lead to concluding that the datasheet value for Er was incorrect, and might result in attempting to meet the impedance value with a revised geometry.
Polar is confident that laminate suppliers provide accurate measurements for Er and believe that de-embedding the DC resistance allows better correlation of results without artificially adjusting Er values.
The theme of the third conference session was material technology for next-generation products. It was moderated by EIPC treasurer Emma Hudson.
Alexander Ippich, technical director, signal integrity and advanced technology with Isola in Germany, discussed comparative testing of insertion loss performance on printed circuit boards.
Four popular ways to measure insertion loss were listed in IPC-TM-650 126.96.36.199A: vector network analyzer (VNA), IBM short pulse propagation (SPP), Intel SET2DIL, and Intel Delta-L. Ippich summarised the details of each, commenting that there is no standardised test structure or coupon and that the results can be influenced by PCB processing and stackup parameters.
But in order to carry out meaningful comparative testing, it is necessary to decide on one test method, use a consistent test coupon, and keep potential differences in PCB processing small (ideally by using the same PCB shop and processes), and create stackups closely matched in dielectric thickness, with similar weave styles, and resin contents and the same copper type.
He showed a practical example, comparing one of Isola’s low-loss laminates with another material in similar eight-layer stackups, with thicknesses and parameters as closely matched as practicable. A second example compared single-ended stripline losses at 28GHz, plotting dB per inch against line width for various grades of Isola’s halogen-free material. A third example compared insertion loss for surface microstrips on RF/MW materials.
Dr. Manfred Huschka, vice president of AGC Group’s RF Business Unit, discussed base materials with high electrical and mechanical reliability as enablers for millimetre-wave PCBs.
He began by making it clear that in vehicle-to-vehicle communication systems, advances in one area rely on technological growth from other areas of the supply chain.
Substrates for millimetre-wave PCBs require the lowest dielectric loss and the lowest moisture absorption, together with the best copper insertion loss and lowest copper foil surface roughness.
PTFE laminates have the lowest dielectric loss of all PCB laminates. Huschka showed graphs of Df and Dk vs. frequency for a proprietary ceramic-filled PTFE composite in a microstrip ring resonator, which showed Df approximately 0.002 and Dk approximately 2.96 at 100GHz. These values could almost be reached with the latest developments in thermoset resin laminates.
The higher the frequency, the more the insertion loss increases with increased moisture absorption of a laminate, whereas effective Dk decreases. Clearly, laminates with the lowest moisture absorption perform best. Huschka listed moisture absorption figures for three substrate types: unfilled PTFE laminates 0.03–0.03%, ceramic filled PTFE laminates 0.05–0.07%, and PPE/PPO laminates 0.11–0.19%.
Regarding copper insertion loss and copper foil surface roughness, the lower the copper foil treatment profile, the less the treatment becomes embedded in the laminate surface during the bonding process, so there is less to get etched out. Therefore there is less time for the etchant to attack the sidewalls of the circuit traces, so these remained steeper, resulting in better insertion loss. Huschka demonstrated the effect by plotting insertion loss vs. frequency for a low loss laminate clad with ultra-low-profile, rolled-annealed, reverse-treated, and very-low-profile copper foils.
He completed his presentation by summarising the mechanical and thermal properties of AGC’s dimensionally stable low loss laminate.
The next contribution to the material technology session came from Andreas Folge, 5G OEM Marketing Europe for Nan Ya Plastics Corporation, using the example of 5G as the basis of his discussion of laminates for high-tech requirements.
He introduced 5G as the fifth generation mobile network, a global wireless standard invented by the 3rd Generation Partnership Project (3GPP) in 2018. The three main classes of applications for 5G were Enhanced Mobile Broadband (eMBB), massive Machine Type Communication (mMTC), and Ultra-Reliable Low Latency Communication (URLLC).
Although in the short term, much of the 5G network infrastructure deployment will use sub-6 GHz frequencies, millimetre-wave systems will grow in the medium term and the higher frequency systems will require greater innovation and material developments. Some key words for copper-clad laminates are “low loss,” “ultra low loss,” and “high layer counts.”
So how to develop materials with excellent electrical performance? The basic requirements are for a low-polarity resin with a symmetrical structure, spread cloth with low-Dk glass, and very-low-profile copper foil.
His graph of Df vs. Dk for different resins showed the trend to higher operating speed and lower signal loss as the chemistry moved between the extremes of epoxy and PTFE, passing polyimide, cyanate ester, polystyrene, polypropylene, polyethylene, polybutadiene, and polyphenylene ether along the way.
He demonstrated the difference between standard weave and spread-weave glass cloths, the latter having more uniform Dk distribution and better anti-CAF properties. And whereas standard E-glass had Dk of 6.5 to 7.2, and Df of 0.006 to 0.008 at 10GHz, the corresponding values for low-Dk glass were 4.6 to 5.0 and 0.003 to 0.004.
He also showed how improvements in the surface profile, microstructure, and barrier design of the copper foil improved signal transmission speed, decreased electron scattering and optimised insertion loss, heat performance, and oxidation resistance.
Nan Ya has the benefit of producing all of its copper-clad-laminate raw materials in-house, with complete upstream vertical integration, and 5G has driven the development of new laminates for millimetre-wave applications as well as its material ranges directed at high-layer-count, automotive, HDI, and IC substrate technologies. Folge listed the general properties of their PTFE, polyphenylene ether, hydrocarbon, halogen free and phenolic materials in terms of Df and Dk.
The industry was at the early stage of the 5G business cycle. In 2020-2021 the strongest growth segments were in networking, cloud computing, data centres, gaming, and smart consumer electronics. Wired and wireless infrastructure equipment became a key driver for market transformation, and there was more and more focus on special multilayer boards and high-end packaging substrates driven by high-speed, high-frequency, and high-thermal demands.
5G offered growth opportunities: Folge commented that 5G-related infrastructure and device demand will continue to increase further worldwide, with the pandemic giving additional momentum as a consequence of remote working, teaching, learning, gaming, shopping, etc. Market segments such as data centre, networking, PC, wired and wireless infrastructure, 5G smartphones and portable devices remain strong, and automotive and industrial applications will follow once the 5G infrastructure in Europe is fully deployed.
The final presentation of the session came from Alan Cochrane, president, North America at ITEQ Corporation, discussing a new high-resin-content construction for loss improvement.
The starting point of Cochrane’s line of reasoning was to question the assumption that the Dk and Df values of core and prepreg were the same. Clearly they would actually be different due to their different resin contents. And when the Dk/Df difference between glass cloth and resin was larger, the phenomenon would be more obvious. If the resin contents of core and prepreg were different, this assumption would cause the simulation result to be distorted
He used the equations:
Dkcomposite=Dkresinx PercentageResin+Dkglassx(1- PercentageResin)
Dfcomposite=Dfresinx PercentageResin+Dfglassx(1- PercentageResin)
to calculate the relative Dk and Df values for core and prepreg and to demonstrate that when cores and prepregs of the same thickness have different resin content, they also have different Dk and Df. He showed the results graphically at 10GHz.
He also showed some examples of high-resin-content ultra-low-loss core materials, single-ply 3 mil and 4 mil, and two-ply 8 mil, on 1035, 1086, and 1078 glass styles, with resin content ranging from 68% to 78%. These were used in an experimental loss-comparison with equivalent standard-resin-content materials in a 12-layer stackup. A series of simulation experiments was also carried out.
The results demonstrated the benefits of the high-resin-content stack-up, particularly that board thicknesses can be reduced while keeping the same loss performance, and that crosstalk can be reduced. The aspect ratio of plated through-holes was also reduced, with yield benefits in drilling and plating. And half-ounce copper can be replaced with one-ounce for better loss performance.
Following the busy conference programme, the first day was rounded off with a privileged visit to the headquarters of Ericsson Mobile Communications in Kumla, followed by a splendid networking dinner at the Restaurant Frimis Salonger, back in Orebro.
With grateful thanks to Alun Morgan for the excellent photographs.
Pete Starkey is a technical editor for I-Connect007.
Continue reading Pete's review of Day 2 of this year's conference.