This company has introduced a new reworkable underfill encapsulant designed to underfill package-on-package (POP) assemblies.
This company has introduced
a new reworkable underfill encapsulant, CN-1728, designed to underfill
package-on-package (POP) assemblies. Underfilled POPs have greater difficulty passing
thermal cycle tests than underfilled BGAs. 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 one minute at 150°C. These
properties make the underfill particularly well suited for high-volume, high-speed
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.
For more information, e-mail
ZYMET: Reworkable Underfill (9/22/09)
September 22, 2009