Robust pad layout to improve wire bonding reliability

Abstract

Different from the conventional study to improve the pad reliability against the peel-off, this study focuses on the probability that the peel-off could be originated from the perpendicular pushing down mechanical stress (PPMS) during the ball mounting process. Suggested in this paper are a new model which causes the peel-off and a new pad structure that overcomes the pad peel-off without any special procedures or changes in material or dimension. Three sets of layout patterns have been designed and fabricated in a 0.13 µm CMOS process. To assess the wire bonding quality, wire pulling tests (WPT) and evaluation of bonding power dependencies by means of wedge wire bonding are conducted. Additionally, FAMMOS simulator is adopted to verify the newly proposed pad structure.