The strength of flip chip organic packaging technology rests upon the knowledge and manufacturing base of C4 solder bump chip interconnection, and printed circuit technology infrastructure. The key innovation was the underfill encapsulation between the chip and the laminate which overcame the road-block of low cycle fatigue of C4 solder bump due to large CTE difference between silicon and laminate. The advent of SLC (surface laminar circuit) innovation extends the flip chip technology to higher solder bump density and larger chip I/O expected for future generations of semiconductors. The flip chip packages contain new materials, interfaces, and new processes which in turn govern the mechanical integrity of the packaging module and module card assembly. The increasing pervasiveness of electronic packages requires meeting new sets of environments. It is important to have a good understanding of materials, interface, metrology and mechanics issues related to organic packages, and how to apply this understanding in the modelling of design, process and reliability of flip chip. This paper will deliver an overview of some of the key technical challenges associated with materials and mechanics in FCA (flip-chip attach) assembly on organic carriers.