Electrical functionalization of thermoplastic materials by cold active atmospheric plasma technology

Plasmadust® is a new technology using cold active plasma for additive metallization of different substrate materials. For electronics production, in particular Molded Interconnect Devices (MID), thermoplastic materials can be structured with copper as power electronic conductive pattern. The main advantages of Plasmadust® are the controllable process temperature range between about 90°C and 180°C, the good adhesion of the metallization, the fast process speed of about 100 mm/s and the fast growing conductor tracks with about 15 microns thickness per cycle. Plate specimens were made of PA, a thermoplastic commonly used in automotive applications, with different process parameters. Conductor tracks applied onto the substrates consist of one line with different electrical and mechanical properties according to the process temperature and process speed. Additionally, the thickness and the width of the conductor track depend on the process parameters. The setting of the process speed turns out to be an important influence on the thickness and roughness of the conductor track that can be achieved on thermoplastic substrates. The investigated combination of thermoplastic and copper shows a constant bonding performance during thermal shock testing for 1000 cycles in the range of -40°C and +125°C. An exposure to humidity heat (85% r.h / 85°C) for 500 h has only marginal effects on the adhesion of the printed structures on the thermoplastic substrates, too. This highly promising results provide the base for further investigations to achieve a sufficient ampacity related to standard chemical PCB metallization processes.