Here is the abstract you requested from the IMAPS_2011 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.
|Wafer Level Solder Bumping and Flip Chip Assembly with Solder Balls Down to 30µm|
|Keywords: Solder Bumping, Bump Formation, Flip Chip|
|Flip-chip technology is one of the interconnection technologies with the potential for highest integration and cost savings, what is needed to fulfil the demands of the electronics industry in regard to miniaturization and cost. The paper will present developed processes for solder bumping, particularly with regard to cost efficient Wafer Level Solder Sphere Transfer and Solder Sphere Jetting, as well as automated assembly technologies for processing Flip Chips with 100μm pitch and solder balls down to 30μm ball diameter. Wafer level solder application has been done using wafer level solder sphere transfer process or solder sphere jetting technology, respectively. The latter is a technique that drops a preformed solder sphere onto the bond pad while simultaneously reflowing the ball in-place using a laser. This tool has been used for many years in the wafer level packaging industry for both flip-chip and chip scale packaging applications. It is widely known in the industry as a solder ball bumping tool. For the described work the process has been scaled down for processing solder spheres with a diameter of 30μm, what was never done before that way worldwide. Beside the detailed overview on used solder bumping technologies a description on assembly processes for very-low-stand-off applications will be shown. As the underfill process is one of the most crucial factors when it comes to flip-chip miniaturization for high reliability applications, investigations of different underfill material will be presented as well. Therefore, high performance underfill material was qualified by us initially , . Final reliability testing has been done including, but not limited to MIL-STD883G, method 1010.8, condition B up to nine thousand cycles with excellent performance of the highly miniaturized solder joints. Additionally, recommendations for key applications including 3D packaging as well as further miniaturization will be outlined.  Dohle, R. et al.: Landshuter Symposium, Landshut 2009  Dohle, R. et al.: Electronic Systems and Technology Conference, Berlin 2010|
|Thomas Oppert, Vice President Global Sales & Marketing
Pac Tech Packaging Technologies GmbH