Semiconductor Process Materials Flagship

`250LF` Flux

Halogen-free, water-based flux for flip-chip applications

Flux, Reflow & Deflux
Wafer
Substrate / PCB
Solder bump

Request a Quote Request TDS / MSDS

250LF

02Overview

250LF is a halogen-free, water-based flux designed for flip-chip applications. It is suitable for high-density, high-performance and miniaturized packages, providing excellent solderability and cleanability, and is compatible with lead-free soldering processes.

03Features & Benefits

01Special activation mechanism
Although it does not contain strong electrolytes such as halogen compounds, 250LF is activated through a special mechanism, enabling good solderability even under challenging process conditions.
02Excellent cleaning performance
Delivers excellent cleaning performance without highly toxic substances and leaves no flux residue after high-temperature soldering and cleaning, ensuring high reliability and efficiency.
03Improved solderability
Removes only metal oxides without etching base metals such as Cu, Ni and Sn.

04Applications

250LF in the flip-chip reflow process

1 FLUX APPLICATION – 250LF Apply to wafers or PCBs by dipping or spray
2 DIE PLACEMENT Align and place the chip on the substrate
3 REFLOW Reflow soldering on the specified profile
4 RINSE & DRY Rinse thoroughly with DI water, then dry
5 SUBSEQUENT ASSEMBLY Underfill, molding and other assembly steps

Drawn from the application method in the 250LF TDS (apply → reflow → rinse and dry).

Flip chip
High-density, high-performance, miniaturized packages
Lead-free soldering
Wafers · PCBs

05Specifications

Appearance	Amber liquid
Halogen content (%)	None
Specific gravity (20 ℃)	1.06 ± 0.01
pH (TOA HM-7J)	10.5 ± 1.0
VOC content (%)	None
Viscosity (25 ℃, Brookfield #1, 100 rpm)	60 ± 20

06Operating & Handling

1. Apply	Apply 250LF to wafers or PCBs using dipping or spray methods
2. Reflow	Perform reflow soldering according to the specified temperature profile
3. Rinse & dry	Rinse thoroughly with hot deionized (DI) water, then dry
Cleaning (a) distilled water	Clean with distilled water at 50 – 60 ℃ for at least 3 minutes; 250LF is designed for excellent cleanability with water rinsing
Cleaning (b) dedicated cleaner	If minor ionic adsorption is a concern, use a dedicated cleaner (e.g. immersion at 50 – 60 ℃ for 3 minutes), followed by a final distilled water rinse

07Packaging & Storage

Packaging	5 kg · 20 kg · 200 kg, or custom packaging upon request
Storage	Store in a cool, dry and dark place at room temperature with the container tightly sealed
Quality warranty	6 months from the manufacturing date