Kester TSF ULR-18 is a no-clean ultra-low residual tack flux. To meet this market demand, Kester has developed an ultra-low resolution viscous flux with a reflow residue weight of less than 10%, which is reduced by 3 times compared with traditional rosin-based viscous flux, and the trace amount of residue is very reliable , Compatible with post-processing materials.

Kester TSF ULR-18 is a no-clean ultra low residue tacky flux. The product was developed to support the increasing trend in high density, miniaturization, ultra-fine copper pillar and micro-ball bump flip chip IC package where the flux cleaning effectiveness to remove the residue become more challenging. Another segment where ULR-18 is highly recommended is in the Flip Chip on Lead frame (FCOL, FCQFN, etc) package, the kind of device where flux cleaning is not required. The flux residue that may remain after reflow can interfere with subsequent underfilling or over-molding encapsulation which can possibly affect the reliability of the package. In response to this market need, Kester has developed an ultra low residue tacky flux with post reflow residue of below 10% wt, incredibly 3x reduction versus traditional rosin based tacky flux. The trace amount of residue left is highly reliable and is compatible with post process materials.

Recommended Package Type

Flip Chip on Lead Frame, Ultra Fine Pitch Cu Pillar Bump and Micro-Solder Bump, 2.5D, 3D Packaging, Flip Chip MEMs, and others Flip Chip Packaging that do not require flux cleaning.

RoHS Compliance

This product meets the requirements of the Restriction of Hazardous Substances (RoHS) Directive, 2011/65/EU for the stated banned substances.

Recommended Reflow Profile

The typical convection reflow profile for ULR-18 use for various leadfree alloys such as Sn96.5Ag3.5, Sn99.3Cu0.7 and/or other various SnAgCu alloys is shown here. This profile is simply a guideline. ULR-18 was engineered to be versatile and robust for customer reflow process. The optimal profile varies depending on device, component design, fixture, package design and device defect challenges. Please contact Kester Technical Support if you need additional profiling advice.

Product Technical Summary

Health and Safety

This product, during handling or use, may be hazardous to your health or the environment. Read the Safety Data Sheet and warning label before using this product.