SMTA Additive TechXchange Keynote: An Outlook on Advanced PCB Fab

Estimated reading time: 4 minutes

Organised as a virtual event by Lenora Clark of ESI Automotive and Tara Dunn of Omni PCB, SMTA’s Additive TechXchange addressed additive technology specifically in the context of the electronics industry.

I took the opportunity to attend the keynote presentation, an outlook on advanced printed circuit board fabrication, from Jeff Doubrava, managing partner at Prismark Partners, who has spent most of his career in and around the PCB industry and has observed first-hand the innovations that have taken place.

He opened with, “Technology drives the electronics industry.” Innovation, he said, had driven the electronics industry over its 60-year history, enabling the growth of a $2 trillion business, and much of the industry’s recent growth had been tied to the development of massive consumer-facing applications: personal computers, mobile phones, consumer electronics, and automotive electronics. This growth would not have been possible without innovation across the supply chain, which had been focused on the goals of performance, size, and cost. And whilst the application drivers were currently transitioning from consumer-facing to infrastructure, the same targets for innovation applied.

It was evident that, because of market saturation, personal computers and mobile phones were no longer the value-growth drivers in the electronics industry. Currently, the strongest growth is from servers and storage, communications infrastructure, and automotive, which are becoming the main value-drivers of the semiconductor market.

Technology innovation occurred across the whole electronics supply chain, but the pace and visibility of development varied greatly. Semiconductors were the most consistent drivers; displays and batteries impacted selected devices and tended to be driven by disruptive innovations.

For everything else, including PCBs, innovation was more incremental and driven by developments in other markets and the influence of powerful original equipment manufacturers (OEMs) and integrated device manufacturers (IDMs). But it was clear that silicon drove the growth of the electronics industry.

Although not quite matching the pace of the semiconductor industry, innovation in PCBs was focused on similar goals: speed, size, and cost. In terms of feature size, PCB density had increased by a factor of 10 during the previous 30 years, whereas over the same period, semiconductor density had increased a hundredfold.

Other than considerations of cost, PCB innovation continued to be driven by developments in components and the influence of powerful OEMs and IDMs. Recent innovation had been accelerated by advances in displays, personal computers, and smartphones. He illustrated the trend with a chart showing the evolution of the iPhone, and particularly its increasing functionality. The value of the HDI board market was forecast to increase by nearly 6% between the years 2019 and 2024, with substrate-like PCBs (SLP) for smartphones representing the largest growth area. SLP boards were typically made by the modified semi-additive process (mSAP).

The semi-additive process (SAP) was widely used for manufacturing substrates for component packages such as ball grid arrays (BGA), pin grid arrays (PGA), and land grid arrays (LGA), in build-up constructions which had progressed from 6-4-6 structures with 10–12-micron lines and spaces and 50-micron vias in 2015 to forecast 11-2-11 structures with 5–8-micron lines and spaces and 23–50-micron vias in 2021.

Doubrava listed substrate packages and their constructions. A candidate for next-generation build-up technology was a 7-micron film known as Ajinomoto build-up film (ABF), which offered an alternative for redistribution layers, interposers, and fan-out packages. Two-micron line and space capability was claimed, with 5-micron vias produced by a UV laser.

He also described the Qualconn 5G millimetre-wave antenna, built on a 5-2-5 any-layer high-density interconnect 950 microns thick, of which the top five layers formed the interconnect, and the bottom five formed the antenna. The module contained a millimetre-wave transceiver, four patch-antennae, a power manager, power inductors, and a connector for a flex jumper to the main PCB, all within a 19 mm x 5 mm module.

Looking at mobile phone shipments from 2012 to date, with a forecast to 2024, there was not an enormous variation in overall numbers, but clear trends in network generations showing the progressive disappearance of 2G and 3G, the increasing dominance of 4G, and the recent appearance and growth of 5G, forecast to represent 55% of phones sold in 2014.

The growth rate graph for flexible circuits showed significant fluctuation related to mobile phone demand, complicated by computer, communications, and display applications, and was currently flat due to a stagnant smartphone market. Polyimide film laminate remained predominant, but there was growth in the use of liquid crystal polymer material for high-speed low-loss requirements. In a photograph of a stripped-down iPhone, 15 separate flex circuits were visible.

In his concluding summary, Doubrava commented that although never likely to match the pace and acclaim associated with semiconductors, PCB fabrication remained driven by innovation. Material suppliers, equipment suppliers, and PCB fabricators would continue to be rewarded with share gains and improved margins for their developments, focused on performance, size, and cost—if tied to powerful OEMs/IDMs.

And despite the ongoing rotation toward infrastructure, advanced PCB designs will lead the industry, with improved electricals—low loss driven by 5G, advanced servers, automotive ADAS, and increased density—advanced packaging and high-density portables.

An excellent overview with notable statistics and analysis and some knowledgeable forecasts. Many thanks to Jeff Doubrava for his contribution and to Lenora Clark and Tara Dunn for organising a most interesting event.