2020 EIPC Winter Conference, Day 2

Estimated reading time: 9 minutes

Editor’s note: Read Pete’s recap of the 2020 EIPC Winter Conference, Day 1, here.

Rested and refreshed, delegates returned to the conference room for the second day of the 2020 EIPC Winter Conference in Blijdorp, Rotterdam, South Holland. The first session on new technologies and design was moderated by EIPC board member Martyn Gaudion from Polar Instruments. He was delighted to welcome back Dr. Despina Moschou, assistant professor at the University of Bath in the U.K., for her update on recent developments in the design and manufacturing of lab-on-PCB devices.

Dr. Moschou gave a brief introduction to the University of Bath—a centre for biosensors, bioelectronics, and biodevices, developing technologies to improve biomedical diagnosis, environmental monitoring, industrial bio-processes, and the understanding of biological functions. “Lab-on-chip technology is no longer science fiction; it’s actually happening!” She drew a parallel with the progress of the development from the old fashioned computer to present-day “system-on-a-chip” integrated circuits.

The lab-on-chip micro-total-analysis-system (?TAS) offered unique advantages in miniaturization, low reagent volumes, rapid analysis time for early detection, together with automation and portability. But economic manufacture of integrated smart microsystems on silicon relied on economies of scale, and there was no established commercial manufacturing technology. The lab-on-PCB approach had emerged as a very strong candidate, owing to its inherent upscaling potential: the PCB industry being well-established world-wide, with standardised fabrication facilities and processes.

Many material and process options were currently available commercially, and prototypes compatible with lab-on-chip dimensions and requirements had been demonstrated for various applications. Dr. Moschou showed many examples of lab-on-PCB devices and reviewed some of the challenges that had been encountered and overcome. The concept was truly cost-effective in mass production, and work was continuing on standardization and engagement.

Jean-Paul Birraux, sales and marketing manager for First EIE in Switzerland, discussed direct imaging, versatile automation, and data format management, remarking that First EIE had more than one thousand installations of imaging equipment worldwide. He referred to the acquisition of the company in 2015 by Inspec in Japan, commenting that the strong synergy and complementary product portfolio extended their range from imaging to include automatic optical and visual inspection, automation, and roll-to-roll technology.

Birraux went on to describe First EIE’s latest CFX-compliant direct imaging system, which could be configured in several configurations from a single stand-alone machine to a fully automatic line. They continued to use their proven mercury UV light source, which gave a full spectrum from 350–465-nanometre wavelength. The system was capable of accepting all data formats and resolving 20-micron features. A new glass-mask-imaging system had been developed, capable of resolving 15-micron features on large-format chrome masks for applications including LCD, TFT, OLED, and touch panel manufacturing.

Hans Fritz, owner of SAT Electronic in Germany, described a new innovation for PCB registration improvement developed by InPeKo and launched at productronica 2020: a multilayer ultrasonic welder. With videos, he demonstrated how two cameras detected layers and prevented incorrect layer build-up. Accuracy was better than 10 microns. There were four welding heads, and the actual welding process took less than one second for stack heights up to 9.5 mm. The very small weld area saved space on the outer border of the layer, which could be as narrow as 6 mm. The major benefit of the ultrasonic welding process was that heating was very localised, generated only in the prepreg. Therefore, there was no thermal distortion of the material beyond the welding point. An added capability was “aufslippen,” meaning that prepreg could be welded to the external surfaces of the stack if necessary.

The concept of the machine was flexible and modular, with options from semi-automatic to fully-automatic, and it could be adapted to provide customer-specific solutions. In its standard format, it could handle panel sizes from 500 x 330 mm to 700 x 800 mm with real-time control of temperature, time, and energy.

The final session, on manufacturing technologies and new processes, was moderated by EIPC board member Oldrich Simek, owner of Pragoboard in the Czech Republic, and his first presenter was Joan Tourné, CEO of NextGIn technology in the Netherlands.

Tourné explained the concept of “vertical conductive structures” (VeCS) as a means of increasing the efficiency of high-density interconnect in terms of increasing the connection density, simplifying the laminating process, and reducing signal distortion. He clearly demonstrated the principles using X-ray and microsection photographs of actual VeCS interconnections.

There were two classifications: VeCS 1 used all through-slots, and VeCS 2 used multiple depths of blind slot. In either case, the slots were formed by routing or peck-drilling, then metallised and plated, then drilled over-size at intervals to leave a series of vertical conductors on the walls of the original slots. Tourné stressed that any board shop with the capability to produce high-end circuits could manufacture VeCS with no additional investment in equipment or process.

Tourné showed many examples of VeCS designs, discussed how detail process improvements had been made, and reviewed the results of reliability testing. He explained how VeCS 2 could be used to produce separate circuits on top and bottom of the panel to increase density and make better utilisation of routing space without vias penetration through the board with no sequential lamination being required. Connections could be created for power-hungry power and ground applications, and stubless connections made to internal layers without back-drilling. He acknowledged the development and evaluation work carried out in China by WUS PCB on real-life products.

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