Electrical characterisation of BGA package for RF applications

This paper highlights the electrical behaviour of the interconnects on a 120‐pin Ball Grid Array (BGA) package from 500 MHz upto 8 GHz. The measurements are made using IMEC's MCM‐D thin film technology as the substrate and with a test set‐up called MoPoM (MCM‐on‐Package‐on‐MCM). The interconnects are classified based on length and measured with adjacent interconnects grounded as well as floating. Circuit models are extracted from the measurement and the simulation respectively for an RF interconnect including the wirebond. Comparison of the circuit models with each other and with the measurement show agreement atleast upto 6 GHz. One of the interconnects is also measured before and after globtopping and a considerable change in the impedance match is observed. The effect of package loading is found to be negligible.