Wafer Fluxes

Wafer fluxes are low-viscosity rheologically-optimized, semiconductor-grade liquid fluxes that are applied to the surface of the wafer and reflowed after:

• Solder deposition (usually plating)
• Solder bump deformation or coining, after known good die (KGD) probe testing

Recommended products:

Wafer flux WS-3543

• Application: spin-on and reflow
• Attributes: shiny, co-planar symmetrical solder microbumps

Flip-Chip Fluxes

Flip-chip fluxes are moderate viscosity liquid fluxes or rheologically plastic materials used to solder a bumped or copper-column flip-chip to a substrate in the direct chip-attach process. The substrate pads may be metallized/OSP-bearing, pre-bumped with solder or printed with substrate paste.

Recommended products:

Flip-Chip Flux WS-641

• Application: dip, place die, or TCB (reflow)
• Attributes: reliable solder interconnects

Flip-Chip Flux WS-3555

• Application: spray, place die, or TCB (reflow)
• Attributes: shiny, co-planar symmetrical solder microbumps

Copper-Pillar Flip-Chip Fluxes

Copper-pillar flip-chip fluxes are designed for use in thermocompression bonding applications. Their rheology and chemical design enable their use with dipping depths down to 10 microns or less, and film thicknesses (spray fluxes) down to 5 microns or less.

Recommended products:

Cu-Pillar Flip-Chip Flux WS-641

• Application: thermocompression bonding flip-chip copper pillar applications
• Attributes: enables dipping depths down to 10 mincons or less