I am using a C8051F930-GDI in die package and are connecting the die to the pcb by using wire bonding and glue. Is is useful to use conductive glue in order to connect the body of the die to the ground?
The back of the die on Silicon Labs C8051F930-GDI devices is simply a silicon substrate and does not need to be attached to ground. The MCU connections to ground will be via the bond wires from the die to the PCB. Our suggestion is not to use an electrically conductive adhesive but to use a thermally conductive adhesive for heat dissipation. The manufacturing process is also easier using a non-conductive adhesive. In general, your contract manufacture should know the best practice for bare die mounting and you should double check with them.