Journal of Electrical & Electronic Systems

Ghaffarian R

Publications

• Review Article
  Predicted Thermal Stress in Flip-Chip and Fine-Pitch-Ball-Grid-Array Designs: Effect of the Underfill Glass Transition Temperature
  Author(s): Suhir E and Ghaffarian RSuhir E and Ghaffarian R
  
  A previously developed analytical thermal stress model is used for the assessment of the effect of the glasstransitiontemperature (Tg) of the underfill encapsulant and the thickness of the underfill-solder composite bond (USCB)on the induced stresses. The calculations were carried out for two Tg levels, above and below the operation and testingtemperature range for the flip-chip (FC) or the fine-pitch ball-grid-array (FPBGA) assembly with an USCB, and for twothicknesses, 0.05 mm and 0.1 mm, of the USCB. Calculations indicated that the Tg level of the underfill material had asignificant effect on the induced stresses: the normal stresses in the USCB with a low-modulus (low Tg) underfill wereabout half the stresses of the design with high-modulus (high Tg) underfill, and this was true for both thin (0.05 mmthick) and thick (0.1 mm thick) USCB la.. Read More»
  DOI: 10.4172/2332-0796.1000286

  Abstract PDF