The effect of ultrasonic power on bonding pad and IMD layers in ultrasonic wire bonding

The effect of ultrasonic power on the reliability of bonding pad and IMD (intermetallic dielectric) layers has been investigated with numerical analysis and experimental survey. Such reliability can be characterized by maximum equivalent plastic strain in bonding pad and maximum von Mises stress in IMD layers. The whole process of ultrasonic wire bonding is simulated by the finite element method to study the characteristics of ultrasonic power. From the results of this study, we find that the ultrasonic power is closely related to the surface cracking on the bonding pad as well as the fracture of IMD layers.