Reliability of 20μm micro bump interconnects

Abstract

The purpose of this paper is to study reliability evaluation of fine pitch micro bump. In this work, hot temperature storage(HTS) test and electromigration(EM) test were performed for reliability evaluation. We compared microstructure of 20um diameter fine pitch micro bump at 150°C and 180°C. Also, Ni <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> Sn <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> IMC growth rate and Ni UBM dissolution rate at 180 □ were investigated. For HTS 180°C, resistance starts to degrade after 1000 hours. We found that open failure occurred when Ni UBM completely consumed and time to failure is consistent with total consumption time of Ni UBM. In addition, micro bumps shows strong EM resistance.