Electrochemical migration is a form of corrosion that negatively affects the reliability and service life of electronic components. It is caused by moisture—either during the circuit board manufacturing process or due to external factors. Miniaturization and the resulting minuscule distances between conductor paths lead to greater electric field intensity, which in turn increases the risk of electrochemical migration. One example are the control units in vehicles: Fluctuations in temperature can lead to condensation, and this can result in moisture reaching the circuit board. When combined with flux residue, this moisture can lead to negative interactions such as the formation of dendrites and eventually lead to short circuits.
Microbond® SMT650 solder paste achieves a consistently high surface resistance that prevents electrochemical migration. In addition, the specially developed F650 flux system can be combined with different alloys. The combination of the F650 flux system with Innolot alloy delivers superior reliability— especially in miniaturized systems in the automotive industry. Its material composition provides a consistently high surface resistance that prevents electrochemical migration. Furthermore, Microbond® SMT650 is compatible with conformal coatings, solder resist, active and passive components, various PWB materials and combinations. For applications with low thermomechanical requirements Heraeus offers Microbond® SMT650 solder paste with a tin-silver-copper alloy (SAC).
Key benefits of Microbond® SMT650:
- Preventing electro-migration in fine feature applications - no dendrite growth and electro chemical migration is observed for various SIR test after 1500 h
- Excellent thermal mechanical strength, in combination with Innolot alloy
- Clear residue
- Excellent printing
- Efficient wetting
- Residue is compatible with wide range of conformal coating materials
- Type 4 powder for fine pitch applications