PBGA Die Face Delaminations

Pictured

Time Domain Imaging (TDI)™
Utilizes an echo (amplitude & polarity) arrival ‘time’ as a reference, such as standard A-Scan, B-Scan and C-Mode type images.

PBGA Die Face Delaminations

PBGA Die Face Delaminations - Application Note 299

PBGA Die Face Delaminations
C-SAM Acoustic left, optical image middle, diagram right

Sample & Method

A Plastic-packaged BGA was imaged. Gating was on the interface between the molding compound and the die face. The die in this package is positioned with the active side upwards.

Result

  • Red areas along the die face are delaminations of the molding compound from the die face. Die face delaminations are a threat to reliability because they can expand during use until they shear off bond wires.
  • The smaller red areas just outside the periphery of the die show delamination between the interconnect wires and mold compound. Delamination in this region can allow for moisture to collect leading to corrosion of the wires.
  • In the non-defect (gray) regions, C-SAM is so sensitive that it images the distribution of the filler particles in the molding compound.