Sintered Ferrite Thin Plate Noise Suppressor Mounted on IC Chip Interposer

NiCuZn spinel ferrite particles were sintered into 50 μm-thick plate and mounted in between IC die and its interposer to explore their suitability as electromagnetic noise suppressor up to 10 GHz. A 50 μm thick Y-Type hexaferrite plate with density of 5.2 g/cm3 exhibits the figure-of-merit, Ploss/Pin, as high as 0.27 at 7 GHz. The test ferrite plate was embedded in between IC chip and interposer using a newly developed pre-assembly technique. This was enough to suppress on-chip conduction noise and corresponding near field emission by 4-17 dB in wireless communication channels.