Water Soluble Flux for Semiconductor Flip-Chip Attach

ALPHA® WSX-FD water soluble flux is engineered for use in the placement and reflow of high lead, eutectic gold-tin and lead free solders for direct chip attach. It is highly compatible with Cu-OSP, electrolytic Ni-Au and ENIG pad finishes.

Before reflow, this flux provides sufficient tack to hold the flip chip in place. After reflow the flux residue is completely water soluble to enable easy cleaning.


  • High temperature stability – No charring or burning with >300°C eutectic gold-tin or 5Sn/95Sb reflow
  • Tacky to hold the flip-chip component in place
  • High activity for good wetting and solder


  • Pin Transfer
  • Chip Dip
  • Screen Printing, Metal Mask or Doctor-blade
  • Dispense
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