The head-in-pillow defect has become a major challenge in electronics assembly. It refers to the incomplete wetting of the entire solder joint of a ball-grid array (BGA), the chip-scale package (CSP), or even a package-on-package (PoP). Characterized as a process anomaly, head-in-pillow defects take place when the solder paste and BGA ball both reflow but do not coalesce. Poor wetting is one of the main contributors to head-in-pillow defects. It can result from a variety of sources, such as solder ball oxidation, an inappropriate thermal reflow profile or poor fluxing action.
Tackling the root of the challenge of head-in-pillow defects, Microbond® SMT712 represents a state-of-the-art solder paste that promotes excellent wetting. The innovative product is 100% free of Halogen, rendering it environmentally friendly.
It allows for a printing speed of as high as 100~150mm/s, setting a new benchmark for the industry. Extra activity of flux formula could reduce head-in-pillow in BGA soldering. It is specially engineered for use in consumer, communication, computing, automotive sectors in which perfect performance in air reflow process is desperately needed.
The FC712 flux system is specifically optimized for lead-free alloys, e.g. Sn/Ag/Cu. This formula provides superior performance on a variety of surfaces finishes and leaves behind a clear residue. As a result, it eliminates the need to clean flux residues.
Key benefits of Microbond® SMT712:
- Stable viscosity for long stencil life
- Excellent wetting in air reflow
- Good fine pitch printing performance
- Wide process window
- Reduced BGA head-in-pillow defects
- Low voiding in solder joint (less than 3*3mm pad)
- Transparent residue in air reflow