A new 3D power module packaging without bond wires

摘要

The replacement of bond wires in power modules combined with a higher level of system integrationrnhas been discussed for several years in the industry and academia. Most of the new packagingrnapproaches have been based on solder bump interconnection technologies [1, 2, 3] or on embeddedrntechnologies with sputtered or electroplated interconnection layers [4, 5, 6].rnThe new proposed packaging concept is based on flip chip technology but instead of solder balls thernpower chips are attached to a flexible printed circuit board by ultrasonic welding.rnA key material development for this concept has been a flex board with a thick aluminum layer for thernpower connections. The chip is welded by an ultrasonic welding process to the aluminum metallizationrnof the flex board forming a well known reliable Al welding joint. The flexible printed circuit boardrncontains the power routing for the main current path on the bottom side as well as the auxiliary signalsrnto control the IGBT`s on the top side layer.rnSince there is an additional signal layer on top of the power devices a higher packaging integrationrncan be achieved. On the upper layer driver ICs, sensors as well as passive components can be placedrnwithout the need of additional space.