The steady trend for miniaturization of components combined with the increasing demand for selective coatings in electronics packaging requires new solutions for versatile conformal metal coatings. Manufacturing with the established sputtering or plating technologies requires additional complex masking steps, making the processes expensive and material wastage high.
Heraeus Printed Electronics provides a solution for maskless deposition of MOD metal inks for semiconductor applications enabling selective, functional metallic coatings in one single process step. The novel solution consists of a special particle-free silver ink, a printer, and a manufacturing process that uses inkjet printing for 2.5D selective coating. After inkjet printing being established for a long time in the graphics industry, the Heraeus technology offers new design freedom for efficient manufacturing of functional metallic coatings in the semiconductor industry. The maskless selective and precise deposition of the silver ink onto specific areas of the components avoids excess material and minimizes waste, without the use of wet chemical processes, making this process environmentally friendly. The Heraeus solution has a ten times lower power consumption compared to sputtering, resulting in a much better CO2 balance. Established sputtering or plating technologies are energy-intensive multiple-step processes. Complex masking steps are required, due to the increasing demand for selective coatings in combination with component miniaturization, which make the processes expensive and the material wastage high.
The Heraeus full system solution, Prexonics®, enables customized thin metallization films in the range of 150 nm to 3 µm with a conductivity of 20-50% of bulk silver. The industrial scale inkjet printer processes magazines of 300 mm ring carriers on which the components to coated are placed. All process steps are automated and inline: components pre-treatment , inkjet printing of the MOD metal ink and sintering to a metallic silver film. The tool fulfills the standards of the semiconductor industry, and its mass production capability is proven.
This additive manufacturing method is especially suited for EMI shielding of semiconductor packages to secure signal integrity in 5G applications. Digital printing via inkjet enhances the design freedom thanks to maskless selective coating of package topsides, sidewalls (e.g. with stand-off), as well as trenches for compartmental shielding. Shielding effectiveness studies run at a specialized renowned institute confirm that the applied silver film with 2 µm thickness, which is inkjet-coated at the ideal, material saving aspect ratio of 1:1 (side wall to top side), provides excellent shielding performance.