One-Step Underfill 688

- Excellent Capillary Function for Fast Reflow
- Compatible with No-Clean Flux Residues
- Flux Action to Make Solder Connections
- Odorless During Printing and Curing
- Good Storage Properties
- Cures in Lead-Free Profile
- Non-Hygroscopic
- No Voiding


One-Step Underfill 688 is a low surface tension, one component epoxy resin designed as a one-step no-flow underfill for flip chip, CSP, BGA and micro-BGA assemblies. One-Step Underfill 688 improves product reliability through high Tg, low CTE, and good fill with no voiding. Even though One-Step Underfill 688 does not require flux, it is compatible with no-clean flux residues and provides excellent adhesion. One-Step Underfill 688 can be dispensed directly following solder paste printing, after which components are placed and the entire assembly is reflowed and cured simultaneously in a standard lead-free reflow process. This eliminates the need for a second assembly process and separate cure cycle. The result of this is faster throughput and higher yields that are achieved in one step through excellent capillary action, fast reflow characteristics, and rapid cure speeds. One-Step Underfill 688 may be reworked at 120° C and the viscosity of the product remains stable through out its shelf life. This product wets solder to OSP, ENIG, immersion silver, and immersion tin board surfaces.