Sputtering remains the technology of choice for creating conformal package-level EMI shielding, which itself is a major trend in the electronics industry. For some years now, there have been attempts to replace the incumbent sputtering with spraying. The advantages are low Capex as well as non-vacuum operation, although these advantages may not be enough to overcome the momentum of incumbency.
However, there are now two approaches based on digital printing of conductive inks to create conformal package-level EMI shielding. The digital nature of the coating enables mask-less area-selective metallization, which is an important advantage compared to sputtering when it comes to complex multi-chip heterogenous packaging or SiP package in which only a part of the package will need to be coated.
One approach has been developed by Heraeus. It combines multi-head inkjet printing with their particle-free inks. Heraeus is offering a manufacturing-level turnkey solution, making it easy for customers to adopt its solution. Furthermore, the thin and smooth nature of the coating suggests it is effective even for mmWave frequencies and beyond, meaning that a single solution will suffice to cover sub-5G range, mmWave range, and many future frequency ranges.
Another less mature approach is being developed by Ntrium in Korea. Here, they deploy aerosol printing. The results below were disclosed at TechBlick in May 2021. It shows aarea selective metallization on a 8x12mm2 IC. The aerosol head moves at 10mm/s. The Ag nanoparticle coatings are 1.1- 1.3um thick, which is thinner than spray and in the same range as inkjet. Aerosol offers a focused jet, enabling high resolution, but it may at the same time limit coverage area per pass.
We do not know the latest developments but the plan in May 2021 was to achieve the following until late 2022/early 2023
UPH 1000 /system --> 4000/system
Headspeed: 5mm/s --> 15mm/s
Thickness: 1um/pass -->3um/pass
Width: 500um/pass -->1mm/pass
Comments