High-Performance Structures with Photo-Imageable Pastes for mmWave Applications

Developments in the field of mobile communication (5G, 6G), (autonomous) mobility and the Internet of Things (smart cities, wearables, object tracking, smart grids, video security) are highly topical in the world wide research and industrial landscape. For this purpose, ever higher transmission bandwidths and thus ever higher working frequencies >60 GHz are required. To be able to exploit this potential, new technologies are required to generate high-frequency circuits with which ever finer conductor tracks with ever narrower distances in the range of 10-30 μm each can be realized. For this purpose, thick-film pastes were developed at Fraunhofer IKTS, which can be photo-imaged using UV light and can enable the desired geometric resolutions. The present work is intended to give an overview of the current developments in photo-imageable (PI) pastes at Fraunhofer IKTS and should give a comparison of the PI technologies. On the one hand side the masked based PI process, which is suitable for mass production and on the other hand side, the laser direct imaging (LDI) process, which offers the possibility of prototype manufacturing.