mm-Wave LGA and BGA Package Design and Assembly Challenges

Planar phased array beamforming at mm-wave frequencies requires a small footprint for the multi-channel beamformer ICs driving multiple antenna elements due to commonly employed λ/2 antenna lattice spacing. Low parasitic Land Grid Array (LGA) packages and Ball Grid Array (BGA) packages offer a good balance of RF performance, size and thermal performance. However, the package laminate on which the silicon die is mounted needs careful mechanical analysis over temperature to ensure a robust design free from warpage and die assembly issues. The package to PCB assembly also needs a well thought-out PCB footprint design. The goal of the footprint design is to make it as immune as possible to manufacturing variations of the PCB pads and solder mask, to have sufficient solder dam between pads and deposit the correct volume of solder paste with the stencil design, all while maintaining the necessary high frequency performance. This talk will go over the LGA and BGA assembly challenges and discuss the lessons that can avoid problems associated with mm-wave multi-channel IC assembly.