Indium6.3, Sn63/Pb37 Water Soluble, Type 4, 89% Solder Paste

Main Features

Alloys

Indium Corporation manufactures low-oxide spherical powder composed of eutectic Sn/Pb and Sn/Pb/Ag in the industry standard Type 3 mesh size (J-STD-006). Other non-standard mesh sizes are available upon request. The weight ratio of the flux/vehicle to the solder powder is referred to as the metal load and is typically in the range of 80–92% for standard alloy compositions.

Storage and Handling Procedures

Refrigerated storage will prolong the shelf life of solder paste. The shelf life of Indium6.3 is 4 months when stored at <10°C. When storing solder paste contained in syringes and cartridges, the packages should be stored with tip down.

Solder paste should be allowed to reach ambient working temperature prior to use. Generally, paste should be removed from refrigeration at least 2 hours before use. Actual time to reach thermal equilibrium will vary with container size. Paste temperature should be verified before use. Jars and cartridges should be labeled with date and time of opening.

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.

Printer Operation

The following are general recommendations for stencil printer optimization for Indium6.3. Adjustments may be necessary based on specific process requirements: