Wafer level lead free solder bumping process and characterization

Abstract

The paper introduces an overview of the lead free solder bumping process with a solder paste printing method. The bumping process and process variations for three different lead free solder pastes are discussed. Performance matrices include bump height, bump diameter, and shear strength variations with respect to reliability conditions such as multiple reflows, temperature cycling, temperature/humidity, pressure cooker test, and high temperature storage test, are discussed in the paper.