It was minus six centigrade in the U.K. when I set out to travel to Salzburg for the EIPC Winter Conference, clad in thermals, hat, scarf, and big overcoat, expecting cold and snow. A lot of prospective skiers had the same expectation and were disappointed to find the temperature 12 above and snow only on the mountain tops (ironically, six inches fell in the U.K. whilst I was away and brought transport chaos as usual!).

EIPC managing director Frank Smulders welcomed the packed-house audience, which paid keen attention to a conference programme of 19 papers over two days, introduced by EIPC technical director Michael Weinhold.

The first session focused on management and environment and began with Walt Custer’s market outlook keynote. Walt always succeeds in delivering unbelievable quantities of relevant information whilst keeping his listeners entertained with dry and sometimes wicked humour. The essence of Walt’s message was that although world PCB shipments would grow by six percent to USD 48 billion in 2007, most of that growth would occur in the Far East, whereas Europe would have a flat year—sad, but true. And the continuing strength of the Euro versus the U.S. dollar, together with higher energy, metal, and other material costs, were big concerns. Whether or not to increase prices to offset increases in costs would be an issue to be considered cautiously.

On a positive note, Hans Freidrichkeit gave some encouragement to smaller and medium-size businesses, using case histories of three European companies—Schmid Group, LPKF Laser, and Elekonta Marek—to illustrate how they had successfully tackled the challenges of globalisation. Analysing the reasons why Japan had succeeded in maintaining almost all of its world PCB market share over the last two decades, in circumstances where the U.S. and Europe had each lost two thirds of theirs, he concluded that Japan had kept the lead in “high-hurdle” technologies, all three of the instances he cited being high-growth areas: flexible circuits, chip substrates, and microvia/HDI, and all of which integrated together in products like leading-edge camera-phones. Freidrichkeit’s European examples shared attributes such as innovative management, self-limitation in size, being driven by large customers, investment in employees, and reinvestment of profits. All of these companies had selected the right customers, listened to them, and stayed with the winners by getting into leading technology areas.

Jerome de Boysere’s, Clariant, presentation posed the question: Consequences of WEEE and RoHS—Threat or Opportunity? The objective of the WEEE directive was to shift responsibility for collection, recycling, and reuse of end-of-life electrical and electronic products to their producers. The proliferation of electronic products, together with the shortening of their effective lifespan before being considered obsolete, was resulting in an ever-increasing accumulation of waste. But what was waste? What was end-of-life? A personal computer, for example, would probably be replaced after two years in Western Europe or the U.S. but still be perfectly functional and usable in a less-advanced economy, and many opportunities existed to effectively extend the life of equipment by passing it on through a second-hand-market route. But still the majority of “waste” went to landfills, even after dismantling, and only a small proportion of PCB waste was recovered—whether by crude and environmentally undesirable third-world methods, or by state-of-the-art processes in Western Europe. And a further complication in Europe was that each country had made its own interpretation of the directive and there was no consistency in its implementation. Material recycling of flame-retardant plastics was technically feasible. However, problems remained obtaining a continuous supply of input material that was well defined in its composition. Otherwise, only feedstock recycling or energy recovery were sensible options.

In the second session, on surface treatment and advanced plating technology, Nils Arendt, Ormecon, described an immersion tin plating concept based upon the use of organic metal conductive polymer as a component of the pre-dip chemistry. The catalytic effect of the organic metal gave precise control of the tin-copper exchange mechanism, resulting in a very uniform tin deposit with large, flat crystals. This gave better temperature resistance, improved shelf life, and reduced susceptibility to oxidation and diffusion. Addition of silver to the organic metal pre-dip enhanced the resistance of the deposit to whisker formation by balancing the diffusion rates of tin into copper and copper into tin, reducing the internal stress that is known to initiate whisker growth.

Norbert Schulze, Umicore, explained how palladium functioned as a diffusion barrier in electroless nickel, immersion palladium, immersion gold (ENIPIG) multifunctional coatings. The principles used in palladium pre-plating of lead-frames had been adapted for PCB applications. A 4 to 6 micron electroless nickel, coated with less than 0.05 micron of immersion palladium, and 0.03 to 0.06 micron of immersion gold gave a very cost-effective finish for lead-free soldering and wire bonding. Guido Perrelet from engineering and electronics manufacturing service provider Asetronics gave a user view of the introduction of ENEPIG into a contract manufacturing environment and recounted the exhaustive qualification exercise his company had to undergo to demonstrate to automotive customers the benefits of the finish in functionality and reliability.

Hiroyoshi Toujima from MEC in Japan reported the development of a new generation of super-roughening adhesion promoters for improving the reliability of photoresist, solder mask, and prepreg bonding to copper in HDI circuit manufacture. The objective was to achieve a fine, deep, grain-boundary etch without excessive loss of metal or conductor profile, and MEC’s CZ-2001 product gave significantly better results on cross-hatch/acid-dip/tape-test than could be demonstrated by alternative surface preparation methods.
Paul Sevriens, Dutch Reverse Pulse Plating, described some of the problems in plating distribution that could be resolved using their Easy-Pulse” software. Once the design rules and feature dimensions of the job had been input, this engineering tool calculated optimum pulse plating parameters—total forward current, forward-reverse ratio, forward-reverse frequency, and total plating time—to control the pulse plating rectifier. The parameters could be fine tuned to adjust throwing power for combinations of large and small holes on the same panel, and the system could adapt its algorithm to suit different plating environments.

The third session consisted of three presentations on laminates and prepregs. Bernard Bismuth, CCI Eurolam, made an inspirational contribution, discussing the role of distribution in the future European PCB industry. Recent years had seen not only a dramatic reduction in the number of PCB fabricators but also a fundamental structural change as a consequence of OEMs moving from full integration to “fab-less” operations. Virtually every function was now subcontracted along a supply chain, resulting in an inversion of the direction of technology input—no longer from the OEM, but increasingly reliant upon the material supplier. Encouragingly, Europe had seen some positive signs over the last year. The PCB industry had stabilised due to proximity, flexibility, and interactivity with its customers and strong partnership along the supply chain. The future lay in high mix, high technology, and quick turn, as well as being prepared to expect the unexpected. Bismuth quoted the words of Charles Darwin: “It is not the strongest of the species that survive, nor the most intelligent. It is the ones most adaptive to change.” There were two big dangers, however: a lack of support from the European Union for electronics manufacture, and the attitude of purchasing people to buy on price without an appreciation of true cost.

Jurgen Willuweit, Technolam, discussed how laminate quality and PCB properties could benefit from vertical integration in the laminate manufacturing process. He started by listing the numerous variables, many of which the PCB fabricator was probably unaware of until they began to affect his yields unpredictably, due to inconsistencies in the quality and properties of the laminator’s bought-in raw materials. If the laminator owned the whole supply line, from copper ore, crude oil, and silica sand onward, he had overall control of his process and could offer a homogeneous product to tight tolerances at no extra cost.

Manfred Walchshofer, Panasonic, made a convincing case for laminate to be recognised not just as a commodity substrate material that supports the interconnect, but as a fundamental component of the electronic assembly. As performance requirements continued to increase, laminate properties were being stressed to the limit, resulting in reliability becoming a serious issue, particularly resistance to conductive anodic filamentation (CAF) in high-density designs. In Japan, CAF-resistance was demanded as standard. Phenolic-cured FR-4 resins, because of their lower moisture-absorption, gave better CAF-resistance than their dicy-cured counterparts.

Bert Ohlig, OLEC, gave the first paper of the session on imaging, and he stressed the importance of equipment manufacturers giving the customer what he needed, rather than what he wanted, and seeing beyond what was currently available to offer practical solutions in a rapidly changing world. He compared the relative merits of different light sources—flood, point-source, and collimated—and of alignment systems—2-point, 4-point, and “look-before-you-print.” Good statistical control depends upon the feedback of meaningful data and their conversion into intelligent information. The overall objective was an agile and adaptable system that would achieve high resolution with high yield at low unit cost.

Frederic Baradel, Automa-Tech, explained what could be accomplished using collimated light for high-resolution solder mask exposure and discussed undercut and overhang effects in detail with reference to conductor heights, coating methods, and the balance between exposure and developing parameters. Incremental exposure with collimated light enabled close registration tolerances to be maintained on multi-image panels.

Uwe Altmann, Orbotech, offered analternative exposure concept using laser direct imaging (LDI) as a volume production—rather than a small batch—technique. The benefits of accuracy and dynamic scaling could be realised in shorter cycle times as higher-power laser sources and more sensitive photo-resists became available. Additional features, such as individual serial numbering and date coding, could be straightforwardly incorporated into the image as part of the LDI process. Questions from the floor provoked some animated debate as to how capital and unit costs and value-in-use considerations compared with phototool-based exposure systems.

The first day’s programme concluded with a social event, the details of which were not announced in advance, although it is inevitable that any visit to Salzburg will somehow involve Wolfgang Amadeus Mozart (even the airport is named after him). EIPC didn’t disappoint—an evening tour of the city then dinner to the accompaniment of Eine kleine Nachtmusik with a chamber ensemble of two violins, viola, cello, and double bass, complemented by tenor and mezzo soprano in good voice and traditional costume!

Suitably stimulated and refreshed by their cultural evening, delegates took their seats promptly for an early start to the second day. The first session subject was advanced technology, and Joerg Sperling, Jumatech, described a cost-effective interconnection solution that was finding increasing applications in automotive electronics, particularly where high currents needed to be carried on specific areas of the circuit. PCBs were fabricated by standard techniques using standard foil thicknesses, but wires were welded on where additional current capacity was required. The wires could be round or flat in cross section, were available in a range of capacities, and offered the facility to incorporate bendable areas into a design for three-dimensional applications and to eliminate connectors. No special EDA tools were required, and the welding was carried out as a subcontract service on either inner or outer layers.

Thomas Gottwald, Schweizer, presented a volume-production technique for chip integration into PCBs that overcame many of the limitations of earlier methods. In essence, the chip was pre-assembled to a thin interposer circuit that had break-out conductors terminating in pads large enough to give an adequate target for straightforward via-hole interconnection, whereas earlier methods relied upon critical registration of laser vias to make connection directly with I/O pads on the silicon. An additional advantage was the ability to fully electrically test the subassembly before bonding it into the multilayer printed circuit structure. Reliability tests had shown outstandingly good results.

Hermann Reischer, Polar Instruments, tackled the complex topic of predicting transmission line loss and clarified many of the mysteries with plain-language explanations of the characteristics of high-frequency conductors. Historically, engineers had been principally concerned with impedance matching from a point of view of reflection, but for the future it was becoming more appropriate to characterise lines in terms of loss; managing the “loss budget” was a key concern for designers who would need to communicate very closely with fabricators to optimise performance. Reischer discussed the causes of conductor and dielectric losses with reference to material characteristics. The skin effect became more significant at higher frequencies and was exaggerated by the use of nickel-gold finishes because the ferromagnetic nature of nickel resulted in much lower conductivity than copper. His advice was to use nickel-gold selectively, only on terminations, and not as an all-over conductor finish.

The closing session highlighted solder mask technology to meet RoHS and WEEE requirements and included papers by Ian Macdonald, Sun Chemical; Manfred Suppa, Lackwerke Peters; and Anders Ekman, Huntsman. Macdonald discussed process, performance, and legislative requirements and the fact that volatile organics constitute a significant environmental issue. The solvents concentration of the ink formulation varied with coating technique, from less than 20 percent for flood-screen application to more than 50 percent for air-spray, and each kilogram of coating solvent had a carbon dioxide equivalent of 2 kilograms.

Suppa commented that although being green was easier for Kermit the Frog than for a solder resist manufacturer, environmental considerations were just as important as product performance in current developments. It had been shown that the overall eco-balance of a polyalcohol-developing solder resist was superior to that of the equivalent soda-developing material, and that the solvent-developed product had better thermal performance.

Ekman reported the latest developments in solder masks for LDI. Close cooperation with the equipment manufacturer had resulted in the production of a functional polymer binder customised to give optimum photo speed at the 355 nanometre wavelength of the laser source, whilst remaining compatible with conventional exposure machines working at 365 nanometres. One coating line could thus feed two alternative exposure systems, and 25 micron solder dam resolution could be achieved where required.

Frank Smulders brought the proceedings to a conclusion, thanked the presenters and the tabletop exhibitors for their support, and remarked upon how successful the conference had been in bringing together over 80 delegates from 15 countries to network, share knowledge, and understand Europe’s position in the global PCB industry and what its prospects for the future were. The next event was planned for June 2007 in Edinburgh, Scotland.

EIPC has a long-standing reputation for organising first-rate conferences, and the Salzburg event was as excellent, as we have come to expect. Europe definitely has a future in PCB manufacture, as long as people think as Europeans instead of as 27 different nations and continue to be technically clever and commercially agile, flexible, and service-orientated.

And although many flights back to the U.K. were cancelled because of the snow, I was able to get home OK. My treasured trilby hat, alas, stayed behind in the airport taxi...