SMQ80 Solder - Indium Alloy 227, T4 (89 Percent), 100g Jar
NC-SMQ80 is a halide-free, no-clean solder paste formulated for use with indium-based alloys. Indium-containing alloys offer the benefits of reduced leaching/scavenging of metallizations of precious metals like gold or silver, and improved ductility to compensate for coefficient of thermal expansion (CTE) mismatches between dissimilar materials. NC-SMQ80 is a medium residue, air-reflow paste with exceptional wetting capabilities. NC-SMQ80 meets or surpasses all ANSI/J-STD-004, -005, and Bellcore test
Alloys
Indium Corporation manufactures low-oxide spherical powder composed of Sn/In/Ag and numerous indium-based alloys 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 83–92% for standard alloy compositions.
Storage and Handling Procedures
Refrigerated storage will prolong the shelf life of solder paste. The shelf life of NC-SMQ80 is 6 months at storage temperatures of -20–5°C. Storage temperatures should not exceed 25°C. When storing solder paste contained in syringes and cartridges, they should be stored 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 adequate release of solder paste from stencil apertures, a minimum aspect ratio of 1:5 is suggested. The aspect ratio is defined as the width of the aperture divided by the thickness of the stencil.
Cleaning
NC-SMQ80 is designed for no-clean applications; however, the flux can be removed, if necessary, by using a commercially available flux residue remover.
Stencil Cleaning: This is best performed using an automated stencil cleaning system for both stencil and misprint cleaning to prevent extraneous solder balls. Most commercially available stencil cleaning formulations, including isopropyl alcohol (IPA), work well.
Compatible Products
Rework Flux: TACFlux 012