Monday, October 24, 2016
Publication Date: 10/1/2007
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Henkel Intros 2 New Flip-Chip Underfills
Underfill protective seal.
Irvine, CA — Henkel has engineered Hysol® FP4581 and Hysol FP4583, two advanced liquid epoxy encapsulants designed for use as underfills for flip chip devices. Hysol FP4581 is a high-purity, liquid epoxy encapsulant formulated specifically for the requirements of high-lead, bumped large die flip chip packages. It has low coefficient of thermal expansion (CTE) properties and improved toughness over previous materials.

The new material forms a rigid, low stress seal that dissipates stress on solder joints and extends thermal cycling performance. Suitable for flip chip devices that require improved crack and fracture resistance, Hysol FP4581 reportedly offers outstanding stress protection. The material is also compatible with most no-clean flux systems.

When applications require an extremely fine filler, Hysol FP4583 embodies many of the same beneficial characteristics as FP4581 counterpart, but contains fillers that are less than or equal to 2 microns in diameter and has been formulated specifically for use with overmolded components in both high-lead and lead-free applications.

In addition to the stress issues associated with flip chip applications, there have also historically been challenges with adhesion to Silicon Nitride (SiN), which is one of the most common die passivations employed by today's packaging specialists. Older generation underfill systems had difficulty adhering to SiN, resulting in delamination and, ultimately, catastrophic device failure. These new Amine-based underfill systems alleviate these issues by offering excellent adhesion to SiN and polyimide. Both new materials have been designed to deliver lower stress with the unique combination of thermal mechanical characteristics to prevent delamination, bump fatigue and UBM failure.

For more information, contact: Henkel Corporation, 15350 Barranca Parkway, Irvine, CA 92618 949-789-2500 Web:

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