Effect of Organic Contamination on Au-Al Wire Bonding Strength

Abstract

In order to investigate the effects of organic contamination for Au-Al wire bonding, IC samples were contaminated in the out-gas from the conductive bond which is used in the IC assembly process. And a part of them were cleaned by Ar ion etching. These samples were analyzed by Auger electron spectroscopy and wire-bonded. Thin ・lms of the wire-bonded samples were prepared by microtome technique and observed by transmission electron spectroscopy. The effects of heating were also investigated by scanning electron spectroscopy and shear test. The results obtained are as follows.(1) At the whole interface of the cleaned samples intermetallic-compound phases are observed, whereas at the interface of the contaminated samples a contamination layer is observed in some places instead of the intermetallic-compound. (2) The cleaned samples are generally higher in shear strength than the contaminated samples. (3) Both the contaminated and the cleaned samples have similar features for the change in shear strength due to heating. (4) Voids are produced by heating along the Au-intermetallic compound boundary.From these results, the effects of organic contamination for Au-Al wire bonding are discussed.