Here is the abstract you requested from the IMAPS_2008d 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.
|Effect of Material Properties on Top PoP Package Warpages|
|Keywords: Package-on-Package , Warpage, material property|
|In recent years, Package on Package (PoP) is an increasing high density package solution for package stacking technology in various device manufacturing applications. Especially, top package with stacked memory packaging system connected to a bottom logic packaging system via solder joint is representative PoP configuration. To guarantee the assembly yield and reliability of the solder joint between the top package and bottom package, mechanical compliance between these two packages is crucial during package stacking. Therefore package warpage needs to be understood and controlled to meet the assembly yield target. As the complexity of the package configuration increases by thinner package thickness, higher number of stacking dies and large package size, the warpage control within the target requirement is very challenging, especially when the material behaviors of substrate, die, molding compound and die attach film are different and also changing as a function of temperature. Therefore, the material property of key component in top PoP package plays a crucial role in warpage performance. The thermo-mechanical properties of molding compounds and die attach film are very important and mainly determine the warpage level of the Top package at room temperature and the warpage behaviors during the reflow profile for the board level assembly with bottom package. Among various material properties, the chemical cure shrinkage, coefficient of thermal expansion and storage modulus for the molding compounds are determining factors on the temperature dependant warpage control of top PoP package. In this paper, the effects of various molding compound material properties on warpage are studied through comprehensive experiment and modeling work. The findings and results provide some clues and guideline for material property selection for warpage control in Top PoP package, which influence the PoP assembly yield and reliability.|
|Myung Jin Yim, Sr. Packaging Material Engineer