Flip chip (also known as direct chip attach) is the process whereby a semiconductor die is attached bond pad side down to a substrate or carrier. The electrical connection is made by means of a conductive bump on the die bond pad.
Au stud bumping requires no Under Bump Metalization (UBM) or special wafer preparation, unlike the requirements for solder bumping. It also offers finer bump spacing than most solder bump technology without the added expense of a solder re-distribution layer.
