To increase the scratch resistance of a surface passivation, in particular, for fingerprint sensors, a antifrictional layer is applied to reduce the shearing forces. The antifrictional layer includes fat, oil, surfactants and/or wax. The antifrictional layer is preferably an emulsion including water, paraffin oil, propylene glycol, stearic acid, palmitic acid, TEA, beeswax, carbormer 954, methylparaben, propylparaben and possibly perfume.