Relevant Materials AM can develop particle populations for package-level shielding when the target chemistry is compatible with the platform Nano Silver: AM has demonstrated spherical, cubic-phase Ag in the 1–100 nm range. By applying a thin layer of nano silver, electromagnetic waves are reflected providing efficient shielding. Nano Copper: Copper is a significantly lower cost and more sustainable metal which typically oxidises quickly. By applying a thin layer of nano copper, electromagnetic waves are reflected, reducing crosstalk. Package-level shielding: As packages become thinner and denser, EMI control is moving onto and inside the package. 5G devices and IoT (Internet of Things) require high frequency communications in a confined geometry. System-in-package, RF and heterogeneous assemblies place multiple functions close enough for unwanted coupling to degrade performance. Package-level approaches use conductive coatings on package tops and sidewalls and conductive pastes in trenches between components. Commercial package-level systems demonstrate uniform spray-on conductive coatings below 5 µm and conductive trench-fill pastes for compartment shielding. At those dimensions, dispersion and the agglomerate tail become manufacturing variables, not just formulation details. Material Mechanisms: Different particle systems can contribute through reflection, conduction and absorption. Conductive network: A continuous conductive pathway reflects and redistributes electromagnetic energy. Percolation depends on conductivity, contact resistance, aspect ratio and loading. Magnetic loss: Magnetic particles or hybrid systems can add absorption mechanisms. Phase composition and magnetic properties must be controlled for the target frequency range. Coating integrity: Thickness uniformity, pinhole control, adhesion and sidewall coverage can be as important as bulk conductivity. Process window: Micrometre-scale coatings magnify every inconsistency in the particle population. Agglomerate ceiling: The largest effective agglomerate must remain compatible with the coating thickness or trench geometry. Spray or trench rheology: Spray coating and narrow-trench filling require different viscosity, solids loading, thixotropy and drying behaviour. Reliability: The shielding layer must survive moisture, thermal cycling and package flex without cracking or delaminating. What to qualify: Shielding effectiveness should be traced back to particle and coating data. - PSD and agglomerate tail after formulation, storage and recirculation. - Particle morphology and, for magnetic systems, phase identity and magnetic response. - Film conductivity versus loading and cure conditions. - Coating thickness, sidewall coverage, roughness, adhesion and cross-sectional uniformity. - Shielding effectiveness across the relevant frequency band before and after reliability exposure. The AM development route: Treat conductivity, morphology, dispersion and the package application process as one development problem. K1 · Particle and formulation screen: Screen compatible chemistries, particle size, morphology and surface state against dispersion, application rheology and early film conductivity. K10 · Package coating validation: Produce repeat material for spray or trench-fill trials, cross-section analysis, adhesion and RF shielding measurements. K100 · Supply continuity: Increase output after the material and coating process are qualified, maintaining the particle population tied to shielding performance. Start with the shielding architecture — Bring your specification: Share target shielding effectiveness, frequency band, package dimensions, coating or trench geometry, application process, maximum thickness, cure limits, substrate and reliability conditions.
