Here is the abstract you requested from the Wirebonding_2013 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.
|The Metallurgy of Wire Bonding: Au, Cu, Al, Ag|
|Keywords: Wire Bonding, Intyermetallics, Ultrasonic Welding|
|Wire Bonding is the dominant chip interconnection method. In 2009 there were more than 12 trillion wire bonds produced with Gold Ball Bonds comprising more than 90% of the total. The flexibility, reliability and yield of wire bonding make it a process worthy of careful study. Today’s wire bonding equipment is capable of producing 16 wires/sec (32 welds) with bond placement accuracy of ±2.5µm. During the descent of the tool the bond head has an acceleration of >300g. Achieving highly repeatable bonds with the stated bond placement accuracy and yet accelerating at 300g requires exceptional engineering design. The wire bonder is one of the worlds most advanced machines requiring high speed pattern recognition, ultra-light, stiff sub assemblies (imaging trying to achieve the same speed and accuracy with a graphite fishing rod), and feed forward control systems. Today, because the price of gold has reached new highs, the gold ball bonding process is being challenged by the substitution of copper wire for gold. Copper provides benefits in cost, improved conductivity and stiffness. However, it is significantly harder than gold and achieving a robust, reliable process is a challenge. Gold, with defect rates in high-volume leadframe applications below 10ppm, presents a significant barrier to entry. This talk will discuss the wire bonding process and some of the variations that are used to produce the stacked die packages (System In a Package (SIPs)) and bumped structures used today. It will provide a comparison between gold and copper wire bonding with their advantages/disadvantages.|
|Lee Levine, Consultant
Process Solutions Consulting, Inc.
New Tripoli, PA