Thermosonic bonding for flip-chip assembly

Thermosonic flip-chip bonding is a new, solderless technology for area-array connections. Its simple, clean, and dry process may significantly reduce the assembly cost for prototyping and manufacturing of MCMs. The feasibility of the technology has been demonstrated by our studies on 64-I/O GaAs-on-silicon test vehicles. But, the repeatability of the bonding quality needs to be controlled. Two process control variables, force and ultrasonic power applied to the chip, will be discussed.