Kester TSF-ULR18 Tacky Flux

Kester TSF-ULR18 is an advanced no-clean ultra low residue tacky flux engineered specifically for high-density, miniaturized semiconductor packaging. Developed by Kester, this innovative flux formula addresses the severe cleaning challenges of micro-pitch interconnects by leaving minimal post-reflow residue, thereby maximizing long-term component reliability.

Key Features of Kester TSF-ULR18

Formulated to support next-generation semiconductor encapsulation and micro-electronic assembly, this tacky flux provides unmatched technical advantages:

• Ultra Low Post-Reflow Residue: Leaves less than 10% wt residue after reflow—achieving an extraordinary 3x reduction compared to traditional rosin-based tacky fluxes.
• Superior Package Encapsulation Compatibility: Trace residues left after reflow do not interfere with subsequent underfilling or over-molding processes, preventing delamination.
• Optimized for Uncleaned Applications: Ideal for non-clean packages like Flip Chip on Leadframe (FCOL, FCQFN) where flux residue removal is physically impossible or not required.
• High Reliability: Chemically benign and non-corrosive benign residue ensures long-term electrical reliability under high-stress operating conditions.

Applications and Usage

This ultra low residue formulation is purpose-built for advanced micro-electronic packaging architectures:

1. Ultra-fine copper pillar and micro-ball bump flip chip IC package assembly.
2. Flip Chip on Leadframe packaging (such as FCOL and FCQFN) where cleaning is omitted.
3. High-density miniaturized SMT assembly requiring seamless underfill adhesion.

Technical Specifications

Conclusion

Integrating Kester TSF-ULR18 into your micro-packaging line eliminates the need for aggressive flux cleaning while safeguarding underfill and molding integrity. For technical datasheets, procurement, or support, visit Contact – LORIOT INDUSTRIAL.