Here is the abstract you requested from the DPC_2012 technical program page. This is the original abstract submitted by the author. Any changes to the technical content of the final manuscript published by IMAPS or the presentation that is given during the event is done by the author, not IMAPS.
|Improved Bond Pad Reliability Prediction|
|Keywords: reliability, advanced packaging, bond pads|
|The criterial for a "good" wirebond, gold wire to aluminum pad, is to have at least 75% intermetallic (IMC) formation. To evaluate the amount of IMC formed requires polishing, FIB, cross sectioning or some other time consuming cumbersome process. The process is also error prone as one assumes the cross section is representative of the entire area. Other test methods such as bump shear and pull testing can damage the die pad area and provide incomplete and unreliable results. In some cases the IMC or entire pad area beneath the bump might be damaged with an assumption that this material was part of the IMC. (Assuming delamination of metal was due to IMC attach was disproven with some very painstaking polishing in a prior job.) A better approach to study the area under the gold bond has been devised that is not destructive to the die and yields a pad that can be rebonded or subsequently plated with ENIG or ENIPIG finish. The DOE in this study involved a control group of die, die cleaned with plasma and die cleaned with BPS 100 (Air Products). The goal is to determine if various cleaning methods could improve an as-is, difficult to bond die, with less than 75% IMC formation up to acceptable standard. In addition an evaluation will be made to determine if percentage of IMC formation is a good correlation to ball shear strength.|
|Terence Q. Collier, President