Magnetic Composite Sheets in IC Chip Packaging for Suppression of Undesired Noise Emission to Wireless Communication Channels

Magnetic composite sheets of ferrite powders suppressed the undesired RF electromagnetic noise emission in a flip-chip semiconductor IC chip package. Their effects were evaluated by the measurements with Si demonstrators and the improvements on wireless communication performance were simulated at the wireless system level. The effectiveness was found to be dependent on the composites -- BaZn-Y hexagonal ferrites exhibited noise suppression by 7dB, which corresponded to the wireless performance improvements by 8dB in the 800 MHz band when the long term evolution (LTE) wireless system is assumed.