Application of resistive graphene lid for suppressing radiation emission in WB-BGA package

Package lid is usually mounted above the complex package substrate to protect die, control warpage and provide a better heat dissipation. Unfortunately, the resonance of radio frequency (RF) signal between package lid and package substrate usually causes serious radiation problem, which could prevent the products from satisfying the relevant EMI standards. In this paper, based on a conventional wire-bonded ball grid array (WB-BGA) package with a package lid, a lid covered by resistive graphene films is proposed to mitigate the radiation emission. The resistive graphene lid achieves radiation attenuation about 10 dB on average and the related process is introduced in detail.