Comparison of Mechanical Properties of Nickel-Palladium Plated and Tin-Plated Copper Leadframe Material at Elevated Temperatures

In this paper the mechanical properties of Copper-based (Cu) leadframe with Tin (Sn) and Nickel-Palladium (NiPd) finishing are compared by using nano-indentation technique. Cu leadframes with the two types of finish materials are subjected to high temperature storage condition (HTS) of 150°C for 750 hours. Nano-indentations are performed at room temperature (25°C) and at elevated temperatures (125°C and 175°C), on samples before and after HTS, to compare the temperature response of the two leadframe finish materials. In the case of Sn plated leadframe, intermetallic compound formed influences its mechanical properties after HTS test. On the other hand, Ni crystalline grain properties (grain size and texture) and/or Ni inter-diffusion to Pd layer are of relevance for NiPd plated leadframe.