Interconnect technologies for SmartPower integrated circuits in the area of automotive power applications

In this article the metallization schemes of output DMOS drivers for automotive SmartPower integrated circuits (ICs) are discussed. In contrast to non-automotive applications the main concern is the thermal-mechanical stability of the metallization during inductive switching which leads to high thermal pulses within the metallization. These pulses can result in junction temperatures above 400°C. Additionally, automotive ICs used in under-hood applications encounter rough and fast environmental changes. Rapid junction temperatures changes between -40°C and 175°C result in high mechanical shear stresses within the metallization so that the dielectrics in the metallization can crack. In both cases the thermal-mechanical properties of the chip metallization can be improved by introducing new materials like 11μm thick copper layers on top of the chip for increasing the thermal capacitance of the DMOS and/or material additions within the aluminum to improve its stiffness.