Title :
A study of normal, restoring, and fillet forces and solder bump geometry during reflow in concurrent underfill/reflow flip chip assembly
Author :
Zhao, Renzhe ; Zhang, Yun ; Johnson, R. Wayne ; Harris, Daniel K.
Author_Institution :
Lab. for Electron. Assembly & Packaging, Auburn Univ., AL, USA
Abstract :
Simulation of flip chip solder joints in an underfill environment was performed to evaluate the effect of underfill volume and material properties on concurrent underfill and solder reflow manufacturing technique. Forces during solder reflow, fillet shape and collapsed solder ball geometry after reflow are reported. A multiple ball model was created based on single ball model and underfill fillet studies, to predict die stand-off in the presence of a pre-dispensed, fluxing underfill. The predictions agree with experimental results within 1.5 percent. Modeling allows the prediction of self-centering forces, gap height, and die floating as a function of underfill volume and properties in a no-flow, fluxing underfill assembly process
Keywords :
encapsulation; flip-chip devices; reflow soldering; collapsed solder ball geometry; concurrent underfill/reflow flip chip assembly; die floating; die stand-off; fillet forces; flip chip solder joints; fluxing underfill; gap height; multiple ball model; normal forces; restoring forces; self-centering forces; solder bump geometry; underfill volume; Assembly; Bonding; Flip chip; Geometry; Performance evaluation; Predictive models; Semiconductor device modeling; Shape; Solid modeling; Surface tension;
Conference_Titel :
Electronic Components and Technology Conference, 2001. Proceedings., 51st
Conference_Location :
Orlando, FL
Print_ISBN :
0-7803-7038-4
DOI :
10.1109/ECTC.2001.927809
