Performance of soft magnetic CoZrNb film as a thin film noise suppressor and its application to an noise emulator chip fabricated by 90/65nm CMOS technology are discussed. Intra-chip decoupling was studied by the electromagnetic coupling between two miniature coils made on a noise test chip implemented in CMOS 90nm technology. Inter-chip decoupling (radiation) was evaluated by the coupling between parallel line currents implemented in CMOS 65nm technology chip and off-chip planar shielded-loop coil type miniature magnetic probe. The intra-decoupling was as large as 10 dB at 1.8 GHz where ferromagnetic resonance can be maximized. The inter-decoupling was 7.7 dB at 200 MHz where magnetic shielding is effective. It is found that the product of magnetic film thickness and permeability is a good measure to evaluate magnetic shielding effectiveness for IC chip level inter-decoupling.