Study of nickel contamination on the ultrasonic bondability of gold bond finger of SD-48L packages

Abstract

Contamination is a major barrier to the adhesion of solid-phase metal couples. If me-tallic impurities are present on a gold (Au) bonding surface, it can easily react with oxygen molecules in the atmosphere to form oxides. The oxides formed prevent intimate metal-metal contact which is important for bond formation. A study is carried out to investigate whether nickel (Ni) contamination can affect the ultrasonic bondability of Au bond finger of side-braze 48-lead ceramic package. Two sets of samples are used for this study. The first set comprising uncontaminated packages serves as a control group. The second set are Ni contaminated packages. The results of the study show that Ni contamination does not affect the ultrasonic bondability of the Au bond finger. A second study to ascertain the quality of the wire bonds however shows that the mean bond tensile strength of the Ni contaminated packages has weakened slightly.