• Alloy: Sn63/Pb37
• Type 3 powder (90 percent metal load)
• Quantity: 500g jar
• Excellent wetting reflow in air
• Probe-testable residue

NC-SMQ92J is a halogen-free, air reflow, no-clean solder paste formulated to leave a benign, probe-testable residue. The residue is easily penetrated and will not clog multi-point probes. This product has other qualities such as consistent fine-pitch paste deposition, unsurpassed stencil life and tack time, and excellent wetting. NC-SMQ92J will perform well on high-speed surface mount lines utilizing fast print speeds and rapid chip placement. NC-SMQ92J meets or surpasses all ANSI/J-STD-004, -005 specifications, and Bellcore test criteria.

Alloys

Indium Corporation manufactures low-oxide spherical powder composed of SnPb and SnPbAg in the industry standard Type 3 mesh size. 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 85–92% for standard alloy compositions.

Compatible Products

• Rework Flux: PoP Flux 8.9HF-LV, TACFlux® 020
• Cored Wire: CW-807
• Wave Flux: WF-9945, WF-9955, FP-500, NC-771

Storage and Handling Procedures

Refrigerated storage will prolong the shelf life of solder paste. Solder paste packaged in cartridges should be stored tip down.

Solder paste should be allowed to reach ambient working temperature 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 container size. Paste temperature should be verified before use. Jars and cartridges should be labeled with the 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 the 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-SMQ92J is designed for no-clean applications; however, the flux can be removed, if necessary, by using a commercially available flux residue remover.

Stencil Cleaning is best performed using isopropyl alcohol (IPA) as a solvent. Most commercially available non-water-based stencil cleaners work well.