A look into the future of connection technology

The broad-based lectures focused on global trends such as 5G mobile communications, autonomous driving or increasingly networked systems and the associated requirements for connection technology.

The main challenges posed include the integration of far-reaching functionalities, advancing miniaturisation, higher power densities with demanding thermal requirements, high data rates with high signal speeds and short latencies as well as optimised production processes and materials.

Miniaturisation can only be achieved by increasing the packing density of electronic components, which sees PCB and semiconductor technologies converging. Among other things, AT&S offers a combination of existing and new technologies (AT&S Toolbox), which are designed to work perfectly with each other.

To date, there has been a gap between wafer/chip technologies (fan-out wafer level packaging, flip-chip BGA, interposer-based components) on the one hand, and the PCB/substrate infrastructure on the other for an optimised, miniaturised packaging design.

The structure widths (track/distance) on the chip side are approximately between 2/2 and 8/8µm and on the PCB side currently around 30/30µm. For further miniaturisation it is important to close this gap.

To achieve this, AT&S is currently using mSAP (modified semi-additive process) – in other words, printed circuit board-like substrates, which permit highly miniaturised and precise structures.

Against this backdrop, the roadmap envisages combining PCB technologies (HDI), substrates, embedded technology and possibly active thermal management and shielding to ultimately realise AiOP (all-in-one package) solutions.

“Given the current megatrends such as 5G, networked systems, autonomous driving and M2M communication with ever higher data rates and volumes as well as high power densities, the demands on connection technology are also increasing,” said Walter Moser, CSO of the Automotive, Industrial and Medical business unit at AT&S and moderator of the technology forum.

“As the technology forum has clearly demonstrated, AT&S has worked closely with its customers to deliver a host of innovative solutions so as to continue to offer technology-leading and cost-effective products also in future.”

The introduction of the new generation of mobile communications (5G with frequency bands up to 6GHz and significantly higher), but also automated/autonomous driving supported by powerful radar systems (77GHz) are clear examples of the increasing demands on data rates and signal integrity.

For connection technology manufacturers, this means, for example, reducing signal losses and disturbances by optimising the dielectric material, the material interfaces and also the copper roughness.

In the latter case, for example, it is necessary to overcome the dilemma that, although less rough copper offers advantages for HF applications, a somewhat higher roughness improves the adhesion during printed circuit board pressing.

The geometry (profile) of the tracks also affects signal delays at higher frequencies. In addition, AT&S is also investigating the influence of various metals on the skin effect in the GHz range and, accordingly, is developing new surface materials.

At the forum, high-frequency requirements were also discussed intensively in a number of lectures. Modern simulation tools such as those used by AT&S together with its partners facilitate simulation early in the design phase, for example.

Several lectures discussed the requirements and solutions in terms of system integration (embedded technologies, hybrid boards, embedding cavities, etc.), the structuring for further miniaturisation (thinner printed circuit boards, coplanarity, finer tracks and vias, reduction of the coefficient of thermal expansion (CTE), conductor profile, etc.) and the thermal management with current solutions (heat spread, thermal vias and inlays) and future technologies (heat pipes, embedding of cooling elements, etc.).

The conference also covered other current topics relating to connection technology, such as the embedded power of powerful chips (MOSFETs, etc.) in the printed circuit board, the failure analysis of printed circuit boards, and the investigation of material reliability in solder joint connections.

For the customers, however, less technological aspects and lectures were also interesting, such as cost-efficient design with HDI printed circuit boards as well as the targeted use of the IPC2 and IPC3 classes – both depending on the respective application.

AT&S are well positioned for future requirements. More than 400 research and development (R&D) staff are currently employed worldwide, and the company re-invests almost eight percent of its revenue in R&D. One outcome of this is the close cooperation with international partners and more than 230 registered patents.

In addition to research and development focusing on Austria, production facilities are available in Austria, China, Korea and India. More recently, AT&S has announced an investment of approximately €40m for technology expansion and capacity building for high frequency printed circuit boards at its existing sites in Nanjangud, India and Fehring, Austria.