Electrical sheet resistance and apparent detachment stress of magnetron-sputtered Cu and Ni coatings on epoxy moulding compound

Direct metallisation of epoxy moulding compound (EMC) requires conductive seed coatings that resist detachment. Cu and Ni were deposited on cured HS711 EMC by direct-current magnetron sputtering at programmed quartz-monitor endpoints of 50 and 100 nm; a rate-endpoint audit distinguished these specimens from 60 s screening runs. X-ray diffraction supported face-centred-cubic phase assignments. Three-position four-point-probe measurements yielded mean sheet resistances of 1062 and 696 mΩ sq−¹ for 50 and 100 nm Cu, versus 6116 and 3637 mΩ sq−¹ for Ni. Doubling the endpoint increased sheet conductance by 52.6% for Cu and 68.2% for Ni, below the ideal 100%. Tests on four independently prepared specimens per condition showed apparent detachment stress increased from 0.742 ± 0.048 to 1.208 ± 0.116 MPa for Cu and from 1.310 ± 0.017 to 1.670 ± 0.014 MPa for Ni; all comparisons remained significant after Holm adjustment. The results reveal a trade-off between lower sheet resistance for Cu and higher apparent detachment stress for Ni-seeded stacks. Because geometric thickness, interfacial structure and fracture locus were not independently resolved, this study establishes a screening framework rather than a bonding mechanism or reliability qualification.