There are two main differences between wire-bond and flip chip.
- In wirebond, the I/O pads are placed around the die. In flip-chip, they are placed all over the die.
- In wirebond, the die has the top metal layer facing up, in flip chip, the die is flipped upside down (hence the name), with the top metal layer facing down
Advantage of flipchip (from these website)
•Reduced signal inductance
•Reduced power/ground inductance
•Higher signal density
•Die shrink
•Reduced package footprint