Global Impact on European PCB Fabrication: EIPC Summer Conference 2017, Day 1

Estimated reading time: 18 minutes

Electronics industry professionals from 13 countries, mainly from Europe and Scandinavia, others from the USA, but some from as far away as India and Japan, gathered in Meriden, the centre of England, for the EIPC Summer Conference.

EIPC Chairman Alun Morgan welcomed all present, and acknowledged the support of trade and press sponsors before digging into his archive of industry history and reflecting upon the inaugural Printed Circuit World Convention, in London in June 1978, of which EIPC was a sponsor and a young Rex Rosario, with dark hair and a splendid moustache, was a member of the organising committee. Protégé of Dr Paul Eisler and founder of Graphic in 1968, rewarded for his services to the PCB industry with the Most Excellent Order of the British Empire in 2001, Rex had not missed a single World Convention and had for the last three years been Secretary General of the World Electronics Circuits Council. Past chairman of EIPC, Rex Rosario was delighted to be called forward to receive Honorary Fellowship of the Institute from his current counterpart.

After much applause and flashing of cameras, Rosario returned to his seat as the conference programme got under way with Walt Custer’s business outlook on the global electronics industry, with emphasis on Europe. Although some current market statistics would not be available until a few days after the conference, Custer gave the comprehensive analysis for which he has become legendary, against a background of geopolitical concerns and copper foil shortages. His leading indicators showed improving business conditions and a global resumption in demand, with expansion in most sectors of the world electronics supply chain. Although exchange rates affected growth calculations, and figures varied depending on what base currency was used, it was clear that the European industry had enjoyed a good first quarter and continued growth was forecast in end markets, particularly in the automotive and medical sectors.

Looking at the structure of the European PCB industry, with acknowledgement to Michael Gasch, an interesting analysis was that of Europe’s top 74 PCB fabricators by revenue, representing 1852 million Euros in 2015, half the revenue was shared by the top 20 in the proportions: 1-5: 26%, 6-10: 11%, 11-15: 8%, 16-20: 7%. Gasch had calculated that 2016 figures would be slightly less than those from 2015 and commented that the largest ongoing concern in the industry was the shortage of copper foil which would result in price increases and supply bottlenecks for laminates.

For once, Custer did not need to offer the “unpleasant truth or comforting lies” alternative, commenting, “The truth is pretty good right now!” Europe was strong and business conditions were improving globally. He forecast that the world PCB industry would grow by 2% in 2017 and by the same amount in 2018, although the geopolitical situation remained a major worry.

Recently returned from the Electronic Circuit World Convention in Korea, where he had received an award for Best Paper, Thomas Hofmann, president of Hofmann Leiterplatten in Germany gave a technical keynote presentation entitled “Sharing Experience in Embedding of Active and Passive Components in Organic PCBs for More Reliability and Miniaturization.”

Founded in 1989, the objective of Hofmann Leiterplatten had been to provide innovative fabrication support to electronic designers and development engineers in large OEMs and EMS companies. Amongst many successful developments, the technology of embedding active devices in PCBs was now being widely adopted and was attracting a great deal of attention, ironically from some who had dismissed the concept 20 years ago on the basis that “nobody needs it.” Thomas Hofmann described how embedding technology had evolved since the 1960s with thick film resistors, through the 1970s with proprietary buried-resistor materials laminated into PCBs, to the first examples of Hofmann Leiterplatten’s “Active Multilayer” (AML) in the 1990s. An essential requirement was to completely encapsulate the embedded device with resin, then the benefits of improved thermal properties, environmental and mechanical protection could be realised. Some early concerns had been expressed regarding possible damage to components during the multilayer pressing operation, but these had been demonstrated to be unfounded and a depth of knowledge had been established over many years’ experience of resin flow, press conditions and curing behaviour, together with in-house surface-mount assembly capability. He showed many application examples and a series of practical design guidelines.

Hofmann stressed the importance of cooperation between the PCB fabricator, the electrical designer, the PCB lay-out-engineer, the laminate manufacturer and the component supplier, as well as the assembly specialist and the test engineer, to achieve high first-pass yield. In effect, to achieve the full benefits of embedded device technology, it would be necessary to reconsider the structure of the total supply chain. But he made it clear that this should not be regarded as a disruptive technology, more an evolution of existing PCB fabrication techniques combined with new design, fabrication, assembly and testing methods.

The second technical keynote presentation came from Dr Despina Moschou from the University of Bath in the UK. Well-known for her work on Bio-MEMS and Lab-on-PCB microsystems, Dr Moschou described an inter-university collaborative CHIRP project supported by the British Council and the Scientific and Technological Research Council of Turkey to develop a child-friendly pre-diabetes diagnostic test patch for mass-population preventative screening. The prevalence of diabetes in Turkey was twice the global average, and with a rising incidence of childhood obesity there was a need for a painless, reliable, disposable device. Currently available solutions for diabetes screening were either low-cost but invasive, or non-invasive but high-cost. Lab-on-PCB technology offered a realistic non-invasive, disposable alternative. The proposed system used an array of hydrogel microneedle for the painless extraction of interstitial fluid and a sensing platform based on a flexible PCB. Sample transfer from the microneedles to the biosensor was via plasma-treated hydrophilic microfluidics. Inorganic alternative to enzymes were being investigated for improved reliability of glucose measurement, and a sensor based on copper oxide nanoparticles inkjet printed onto a gold electrode was showing favourable results.

“In the old days, frequency was not an issue” was EIPC Technical Director Michael Weinhold’s opening comment as he introduced the session on high frequency and power. The first presentation came from Martyn Gaudion, ‎managing director at Polar Instruments in the UK, discussing the effects of copper roughness on insertion loss and how to account for it in field-solver modelling. Whereas a DC current was carried uniformly through the cross-sectional area of a conductor, at frequencies of 10MHz and above AC current flowed mainly along “skin” of the conductor. At frequencies around 10GHz, the effective skin depth was less than 1 micron, so the surface roughness of a copper conductor could have a dramatic effect on insertion loss. Electrodeposited copper foil was “treated” during its manufacture to give a favourable surface for bonding to laminating resin, and during multilayer PCB fabrication various chemical processes were used to prepare innerlayer copper surfaces prior to lamination.

So there would always be some degree of surface roughness to be considered when modelling insertion loss. But how to measure it and give it a quantitative value in a calculation to model insertion loss? “All models are wrong but some are useful!” was the often-used quotation attributed to statistician George E. P. Box, to be kept in mind as Gaudion reviewed traditional surface roughness estimates related to equivalent numbers and depths of scratches, but these were only valid for relatively low frequencies. “The higher the frequency and the longer the line, the higher the loss. Maybe not a big issue in a smartphone, but a big problem in a backplane.” Currently the best model was the one proposed by Huray, which considered the copper surface as a series of piles of snowballs to explain how incident electromagnetic waves were reflected and absorbed. It could be simplified by assuming all the balls were the same diameter. But it still remained to determine the best way to physically measure the micro-topography of the surface.Page 1 of 2

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