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Capillary Underfills

Capillary Underfills For Flip Chip Packages

Where things go bump, nobody protects you better than NAMICS.

NAMICS is the world’s leading supplier of capillary underfills for packaging level applications. Underfills are an insulating material designed to flow under flip chip devices to reinforce bumps and mounting boards. The demand for underfill for flip chips, and for reinforcement materials on CSP/BGA, has increased rapidly as applications and reliability requirements have become more diversified. We work closely with raw material suppliers to obtain the optimal resins and fillers; combining the ideal formulating techniques to meet our customer’s current and future requirements for advanced underfills. Our diverse line is formulated to meet today’s demanding advanced packaging technologies.

Today’s cutting edge flip chip packages are utilizing larger, thinner dies with fragile low K coatings to meet the demand for next generation applications.

NAMICS underfills are carefully formulated to provide maximum bump protection and protect critical low K coatings for the life of the part.

Copper pillar technology rapid growth is due to the ability to shrink bump pitch and decrease node size for higher density packages. One challenge for underfills in a copper pillar package is filler separation or settling resulting in a resin rich area with high CTE.

NAMICS underfills for copper pillar applications utilize proprietary filler technology to resist separation and provide superior reliability.

Current and future technology is using higher package density decreasing distance between components requiring underfills to have low resin bleed out (RBO) combined with smaller fillets.

Resin bleed occurs since the resin system will have a higher attraction to the surface. Process like plasma cleaning will increase potential for resin bleed out. NAMICS can dramatically reduce resin bleed out through increasing affinity of filler to resin system and special additive technology.

Growth of 2.1D, 2.5D and 3D packages requires underfills to flow under small, narrow gaps with finer pitch increasing the risk for voids due to filler entrapment in narrow gap.

For fine pitch, narrow gap applications, filler size needs to be reduced to avoid entrapment however the smaller filler size results in significant increase in viscosity. NAMICS balances the maximum filler loading of finer particles to easily fill narrow gap packages and provide void free fill and maintain key properties for a robust solution.


Want to learn more about our Capillary Underfills?

Product Number Pb free bump Cu Pillar Narrow Gap Low K Viscosity Tg Modulus CTE
U8443-14 Yes No Yes Yes 10 Pa-sec 135 C 6.5 GPa 42 ppm
U8410-73C Yes No Yes Yes 50 Pa-sec 88 C 11.5 GPa 31 ppm
U84310-73CF3 Yes Yes Yes Yes 33 Pa-sec 88 C 8.8 GPa 31 ppm
U8410-99 Yes No No Yes 50 Pa-sec 100 C 11.0 GPa 29 ppm
U8410-302 Yes Yes Yes Yes 55 Pa-sec 95 C 12.0 GPa 22 ppm
U8410-314 Yes Yes Yes Yes 15 Pa-sec 128 C 8.3 GPa 30 ppm
U8439-1 Yes No No Yes 60 Pa-sec 70 C 8.0 GPa 36 ppm
U8439-105 Yes No Yes Yes 55 Pa-sec 70 C 8.5 GPa 34 ppm

Want to learn more about our Capillary Underfills?

Board Level Underfill (BLUF) Sales Sheet