Reliability in flip chip and Ball Grid Array is a major concern. Solder joint geometry is extremely important from a reliability point of view. Commonly, the flip chip solder bump takes on the shape of a spherical segment. Mathematical calculations and finite element modeling have shown that the hourglass-shaped solder bumps experience the lowest plastic strain and have the longest lifetime. In...

In response to increasing environmental concern over the use of chlorofluorocarbons (CFC's) to clean printed circuit assemblies, many surface mount operations are converting to water soluble or no-clean type solder pastes. Current trends indicate that this conversion will progress rapidly until water soluble and no-clean pastes constitute the majority of the product mix. With the introduction o...

Interfacial reactions and shear properties of the In-48Sn (in wt.%) ball grid array (BGA) solder joints after bonding were investigated with four different surface finishes of the substrate over an underlying Cu pad: electroplated Ni/Au (hereafter E-NG), electroless Ni/immersion Au (hereafter ENIG), immersion Ag (hereafter I-Ag) and organic solderability preservative (hereafter OSP). During bon...

High-end microelectronic packaging is increasingly moving from wire bonds to solder bumps as the method of interconnection. There are various solder bumping technologies used in volume production. These include electroplating, solder paste printing, evaporation and the direct attach of preformed solder spheres. Flip chip in Package (FCiP) requires many small bumps on tight pitch whereas Wafer L...

SnAgCu is one of the most promising candidates for lead-free solders to replace conventional eutectic SnPb solders. The effects of solder volume on interfacial reactions and microstructure evolution in Ni/Au-SnAgCu-Ni(P) solder joints have been investigated under soldering and thermal aging conditions. The results show that solder volume has a strong effect on the formation of Au-containing int...

Sn-Bi solder with different Bi content can realize a low-to-medium-to-high soldering process. To obtain the effect of Bi content in Sn-Bi solder on the microstructure of solder, interfacial behaviors in solder joints with Cu and the joints strength, five Sn-Bi solders including Sn-5Bi and Sn-15Bi solid solution, Sn-30Bi and Sn-45Bi hypoeutectic and Sn-58Bi eutectic were selected in this work. T...

SnAgCu is one of the most promising candidates for lead-free solders to replace conventional eutectic SnPb solders. The effects of solder volume on interfacial reactions and microstructure evolution in Au/Ni-SnAgCu-Ni(P) solder joints have been investigated under soldering and thermal aging conditions. The results show that solder volume has a strong effect on the formation of Au-containing int...

Thermo-mechanical reliability of the solder bumped flip chip packages having underfill encapsulant was evaluated with thermal shock testing. In the initial reaction, the reaction product between the solder and Cu mini bump of chip side was Cu6Sn5 IMC layer, while the two phases which were (Cu,Ni)6Sn5 and (Ni,Cu)3Sn4 were formed between the solder and electroless Ni-P layer of the package side. ...