Multiphase Analysis of a Solder Joint Using EBSD Alone

The increasing compliance to RoHS regulations (Reduction of Hazardous Substances) in electronics has promoted the development of lead-free solder. Depending on their composition solder alloys produce different multiphase mixtures. Analyzing such samples with EBSD is a big challenge, because phases vary in hardness, which makes sample preparation very difficult.

In this example six different phases could be determined:

  • Tin (Sn): tetragonal
  • Copper, nickel (Cu, Ni): cubic
  • Cu6Sn5: hexagonal
  • Ni3Sn4: monoclinic
  • AuSn4: orthorhombic
  • Ag3Sn: orthorhombic (hex)

The hit rate for each phase depends strongly on preparation success, meaning how well an even sample surface could be attained and local topography suppressed.