Indium 3.2HF Pb-free Water-Soluble Solder Paste - SAC305, T3 (89 Percent); 600g cartridge
Pb-Free Water-Soluble Solder Pastes
Over the last decade, the electronics industry has shifted to no-clean fluxes for surface mount assembly. Despite this industry trend, Indium Corporation has not only maintained a variety of water-soluble solder pastes and fluxes but has revolutionized the category with the release of several new and versatile solder pastes. These solder pastes allow current water-wash manufacturing processes to not only survive but thrive.
Indium 3.2HF
Indium 3.2HF is an air or nitrogen reflow, water-soluble solder paste specifically formulated to accommodate the higher processing temperatures required by the Sn/Ag/Cu, Sn/Ag, Sn/Sb, and other Pb-free alloy systems. This product formulation offers consistent, repeatable printing performance combined with a long stencil life and sufficient tack strength to handle the challenges of today’s high-speed as well as high-mix surface mount lines. In addition to consistent printing and reflow requirements, this solder paste offers superb wetting to the various Pb-free metallizations and has exceptional low-voiding performance on fine-pitch components, including BGAs and CSPs.
Storage and Handling Procedures
Refrigerated storage will prolong the shelf life of solder paste. The shelf life of Indium3.2HF is no less than 6 months when stored at <10°C. Solder paste packaged in cartridges and syringes should be stored tip down.
When refrigerated, solder paste should be allowed to reach ambient working temperatures prior to use. Generally, the paste should be removed from refrigeration at least 2 hours before use. The actual time to reach thermal equilibrium will vary with the container size and the solder paste temperature should be verified before use. Jars and cartridges should be labeled with the date and time of opening. It is not recommended to remove the worked paste from the stencil and mix it with the unused paste in the jar, because this may alter the rheology of the unused paste.
Compatible Products
- Rework Flux: TACFlux 032HF
- Flux Pen: FP-300
- Cored Wire: CW-301
- Wave Flux: 1095-NF
Printing
Stencil Design:
Electroformed and laser cut/electropolished stencils produce the best printing characteristics among stencil types. Stencil aperture design is a crucial step in optimizing the print process. The following are a few general recommendations:
- Discrete components - A 10–20% reduction of stencil aperture has significantly reduced or eliminated the occurrence of mid-chip solder beads. The “home plate” design is a common method for achieving this reduction
- Fine-pitch components - A surface area reduction is recommended for apertures of 20mil pitch and finer. This reduction will help minimize solder balling and bridging that can lead to electrical shorts. The amount of reduction necessary is process-dependent (5–15% is common).
- For optimum transfer efficiency and release of the solder paste from the stencil apertures, industry standard aperture and aspect ratios should be adhered to.
Cleaning
Residue Removal: Indium 3.2HF flux residues are water-soluble and best removed by an inline or batch-type cleaning process using spray pressure and heated DI water. A spray pressure of 60psi and a DI water temperature of 55°C can be used as a starting point. The optimal spray pressure and temperature are a function of board size, complexity, and the efficiency of the cleaning equipment and should be optimized accordingly. We recommend cleaning the flux residue 12 hours (or sooner) after reflow for optimal test performance.
Stencil Cleaning: This is best performed using an automated stencil cleaning system for both stencil and misprint cleaning to remove extraneous solder particles. Most commercially available stencil cleaners and isopropyl alcohol are acceptable.