Electroplated Sn-Au Structures for Fabricating Fluxless Sn-Rich Joints Research
Electroplating
Good economical alternative for vacuum deposition. (Low cost)
Can go beyond the thickness limit that vacuum deposition have
Low processing temperature (40°C ~ 60 °C) à Prevents unwanted diffusion and reaction between Sn and Au
Conventional flip chip processes need resin flux to remove oxides and hold solder bumping devices.
Flux
residues degrade the reliability of the device due to corrosion.
Flux
residues interfere with the flow of underfill encapsultnts and
adhesion.
As
interconnection density increases and pitch decreases, flux residues
are more
difficult to remove.
SAM and SEM images of joints
