Reworkable Underfill for Package-on-Package (POP)

EAST HANOVER, NJ – Zymet has introduced a new reworkable underfill encapsulant, CN-1728, designed to underfill Package-on-Package (POP) assemblies. Underfilled POP’s have greater difficulty in passing thermal cycle tests than underfilled BGA’s. Compared to earlier generation underfills, CN-1728 has a lower coefficient of thermal expansion and higher Tg, and better compatibility with flux residues, both of which contribute to its superior thermal cycle performance.

CN-1728 is a fast-flowing capillary underfill with a viscosity of 900 cps, and it can be cured in as little as 1 minute at 150°C. These properties makes the underfill suited for high volume, high speed in-line processing.

Rework is accomplished by use of elevated temperature, 170°C to 180°C, to remove the underfill fillet. Then, the BGA is lifted from the board after heating it to reflow temperature. Underfill residue is easily scraped off, again at 170°C to 180°C.

Zymet is a manufacturer of microelectronic and electronic adhesives and encapsulants. Its products include die attach adhesives, substrate adhesives, UV curable glob top and cavity-fill encapsulants, and underfill encapsulants.

For more information, contact Zymet, Inc., East Hanover, NJ. Requests for information may also be submitted by Email to info@zymet.com