Autonomous driving, virtual reality and artificial intelligence are all examples of applications that require extremely high data transmission rates. Therefore, 5G is the enabling technology and will take digitalization to a new level. Such high-frequency applications place special demands on printed circuit board (PCB) substrates to ensure error- and loss-free data transmission. The dielectric properties of conventional materials are therefore far exceeded. However, in order to exploit the full potential of 5G technology, new substrates are essential as carrier materials for the corresponding high-frequency components. At the same time, sustainability must be considered during development and processing, and cost efficiency must be taken into account. Therefore, the new publicly funded international project Circuit Foam has been launched, in which an alternative high- frequency material is being researched.

The Polymer Engineering department is focusing on innovative application substrates based on CO2-neutral foamed epoxy systems that set new standards from both a technical and sustainability perspective. The introduction of the gas phase creates a foamed structure of the substrate with excellent dielectric properties, which are manifested in a low dielectric constant and a low loss factor. The CO2 can be extracted from the air in advance, ensuring an overall emission-free foaming process.

Carbamate is used as a blocked hardener, which decomposes at higher temperatures and releases bound CO2. This serves as a blowing agent for the foaming process while the system cures without additional toxic chemicals. However, the use of foam as a printed circuit board substrate presents a significant challenge. To avoid short circuits, the smallest cell sizes (below 30 μm) with only minimal variation in cell size are required. To solve this problem, we combine standard curing agents and the carbamate, resulting in a two-step curing cycle. With this approach, we have the ability to adjust the curing and foaming process to optimize the foam morphology.

We would like to especially thank our project partners #Polymerics GmbH from Berlin and #G&W Leiterplatten GmbH & Co. KG from Dresden. Furthermore, we are especially looking forward to the international collaboration with #Syntez-Project LLC from Moscow, Russia. Special thanks also go to the project sponsor ZIM (Zentrales Innovationsprogramm Mittelstand) of the Federal Ministry for Economic Affairs and Energy (BMWi), who approved the project in the first place.

#innovation #5G #PCBs #circuitboards #IoT #digitalization #polymers #plastics