Effects of Temperatures and Leadframe Surfaces on Wear Rate of the Palladium Alloy Contact Pin

Inhalt:
In the recent years, Palladium-alloy contact pins are commonly used in the test operation and muPPF leadframe becomes a popular type of the package material for the lead/pad types of IC devices. The Pd-alloy pins need work in three temperatures: cold, ambient and hot. muPPF surface is ten times harder than the conventional matt-tin surface. It is important for the test operation engineers to know whether it shortens the contact pin lifetime. A novel methodology is established to characterize the wear rate of the pin tip, by a specially-modified UF200 wafer prober and Q800 dynamic mechanical analyzer, including a set of dedicated pin jig. The experiment is conducted on the both matte-Tin and muPPF leadframe surface at three typical temperatures, -40deg C, 25deg C and 125deg C. The study shows the temperature is a significant factor on the contact pin wear rate. The tip wear on muPPF surface is slightly lower than it on matte-Tin surface. The finding from this work provides an in-depth understanding on the wear mechanism of the contact pin, which offers a guide in defining the design of the testing hardware optimization, and preparing knowledge for the future 175~200deg C temperature testing.