Title :
On Chemical Cleaning for Thermocompression Bonding
Author :
Holloway, Paul H. ; Long, Robert L., Jr.
Author_Institution :
Sandia Laboratories
fDate :
6/1/1975 12:00:00 AM
Abstract :
The removal of a Cr203contaminant oxide film from gold surfaces by a ceric ammonium nitrate (CAN} etch and two different potassium iodide plus iodine (KI + I2) etchants was investigated using Auger electron spectroscopy and thermocompression (TC) bonding. It was shown that CAN effectively attacked and removed the Cr203while the KI + I2attacked the underlying gold film. The KI + I2improved the TC bondability both by undercutting some of the Cr203and by roughening the gold, thereby allowing more deformation to occur,during bonding. The implications of these results on selection of a chemical cleaning agent are discussed. The ability of CAN to dissolve a chromium adhesion layer under the gold metallization has also been investigated. It was shown that a heat treatment of 300°C for two hours in air prevented this undercutting; possible reasons are discussed.
Keywords :
Conducting films; Gold; Surfaces; Thermocompression bonding; Adhesives; Bonding; Chemicals; Chromium; Cleaning; Electrons; Etching; Gold; Spectroscopy; Surface contamination;
Journal_Title :
Parts, Hybrids, and Packaging, IEEE Transactions on
DOI :
10.1109/TPHP.1975.1135042