Here is the abstract you requested from the Wirebond_2010 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.
|Ball Bonding with Pd-Coated Cu Wire|
|Keywords: Copper, Palladium, Process|
|Palladium-coated copper wire has emerged as another low-cost wire option in addition to bare copper wire. Most of the major bonding wire suppliers now offer Pd-coated Cu wire (Pd-Cu wire) in their portfolio and multiple device manufacturers are already using it in fine-pitch applications. Although its cost can be up to twice that of standard copper wire, it is still substantially less expensive than gold bonding wire. Relative to Cu wire, it offers several advantages that may sufficiently offset the added cost in some applications. A key benefit is improved 2nd bond performance, which can result in good mean-time-between-assist rates as well as fast set up and optimization times in some applications. Standard Cu wire generally requires the use of forming gas (5% H2/ 95% N2) during the electric flame off (EFO) process that generates the free air ball at the tip of the wire. Pd-Cu wire is somewhat less sensitive to oxidation and because of this, there have been attempts to bond Pd-Cu with N2 rather than forming gas. This paper will show that Pd-Cu wire can be successfully bonded with nitrogen. Using nitrogen instead of forming gas presents a cost savings, especially by avoiding the infrastructure expense associated with providing forming gas to the factory floor. The 1st bond performance and free-air ball formation of Pd-Cu wire in forming gas and nitrogen are compared using the latest K&S Cu wire bonding technology. It is shown that the results in both cover gases are similar with respect to free air ball shape, shear and wire pull.|
|Horst Clauberg, Senior Scientist
Kulicke & Soffa Industries, Inc.
Fort Washington, PA