A new technology for writing electronic circuits directly onto polymers by modifying surface properties with a laser has been developed as part of the European Appolo project. The technique reduces processing costs by at least three times compared with the current technology used in industry, according to the researchers.
The Selective Surface Activation Induced by Laser (SSAIL) technique was developed at the Centre for Physical Sciences and Technology (FTMC) in Vilnius, Lithuania.
Moulded interconnect devices (MID) – an injection-moulded thermoplastic part with integrated electronics – offers material, weight and cost savings by integrating electronic circuits directly into polymeric components. The parts are used in automotive and consumer products.
Lasers can write the circuits directly by modifying the surface of polymers followed by an electroless metal plating.
Fabrication of circuit traces is the most challenging task in MID production, being both technically difficult to achieve and difficult to make cost effectively.
During the project at FTMC in Vilnius, demonstrators have been built by partners from CRF, BioAge and Elas. The new technique for selective surface plating can be applied to conventional plastics without any special additives, an advantage over the current state-of-the-art technology, laser direct structuring, which uses additives mixed within the polymers. The additives increase the price of the raw plastic material by three to five times, meaning the SSAIL technology lowers processing costs by at least three-fold.
SSAIL is a three-step process: the first is surface modification by laser; second is chemical activation of modified areas; and the last step is metal deposition by electroless plating.
The new technology offers laser writing speeds of up to 4m/s, and therefore spatial plating pitch is kept narrow at 25µm.
The Appolo project is part of the EC initiative ICT Innovations for Manufacturing SMEs. It seeks to establish and coordinate connections between the end-users, knowledge accumulated in the application laboratories of research institutes and universities and the laser equipment manufacturers, in order to facilitate faster customisation of the technology for manufacturing.