WelcoTM Smartflux: Paste for Ball and Flip Chip Attach


Conventional flipchip bumps and BGA attach use flux as for solder joint formation. Very often, yield issues such as cold joints, incomplete joint formation, solder cap creep on copper pillar and missing BGAs are encountered.

WelcoTM Smartflux is a low metal content dipping or pin transfer solder paste, specially formulated for flip-chip bumps and BGA attach. Small amount of fine powder (WelcoTM T6) is added to Heraeus proprietary water soluble flux for improved solder joint formation during reflow process – reducing voids and mitigates co-planarity issues. Presence of solder powder increase metal coalesces; minimizes solder cap creeping along copper pillar walls. WelcoTM Smartflux directly replaces conventional dipping process up to 160 µm bump pitch.

WelcoTM Smartflux FLX89161 is compatible with Welco AP5112 series.

Key benefits of WelcoTM Smartflux:

  • Yield improvement over traditional flux
  • Prevents movement of flip-chips/BGAs
  • Improve metal coalesce during reflow process
  • Ensure good solderability on pad finishes
  • Eliminates pre-washing/clean of Copper OSP substrates
  • Halogen-free
  • Available in SAC305 Type 6 WelcoTM powder