Indium Corporation Features WS-446HF Flip-Chip and Ball-Attach Flux at IEEE EPTC Singapore 2019  

Indium Corporation will feature its new combined flip-chip and ball-attach flux, designed to provide a simple solution to SiP and flip-chip BGA assembly, at IEEE EPTC Singapore 2019, December 4-6, in Singapore.

WS-446HF is a water-soluble, halogen-free flux with an activator system powerful enough to promote good wetting on the most demanding surfaces, including solder-on-pad (SoP), Cu-OSP, ENIG, and surfaces used in embedded trace substrate (ETS), and flip-chip on leadframe (FCOL) .

WS-446HF provides:

  • An activator chemistry powerful enough to deal with a variety of metallizations, yet cleans away completely to  eliminate electrical failures such as dendrites. This is critical for fine-pitch flip-chip applications
  • Tackiness suitable for flipchip and BGA assembly
    • BGA: holding 0.15–0.5mm diameter solder spheres during reflow, eliminating missing balls
    • Flip-chip: Retaining 5×5–15x15mm die in place during reflow, reducing die misalignment and die tilt
  • Consistent deposition in pin transfer, printing, and dipping processes, ensuring consistent joint quality and improving production yields
  • Elimination of multiple fluxing steps, especially in ball-attach assembly, enabling a single-step ball-attach process thus removing the warpage-inducing effects of prefluxing
  • Good cleanability with room temperature DI water (20-35°C), avoiding the formation of white residue

Indium Corporation is a premier materials manufacturer and supplier to the global electronics, semiconductor, thin-film, and thermal management markets. Products include solders and fluxes; brazes; thermal interface materials; sputtering targets; indium, gallium, germanium, and tin metals and inorganic compounds; and NanoFoil®. Founded in 1934, the company has global technical support and factories located in China, India, Malaysia, Singapore, South Korea, the United Kingdom, and the USA.


For more information about Indium Corporation, visit or email You can also follow our experts, From One Engineer To Another® (#FOETA), at or @IndiumCorp.

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