08/07/2012, Irvine, CA

 

New Formulation Reduces Stress and Controls Warpage for Today’s Thinner Die and Substrates

 

Henkel Develops Underfill for Next-Generation Flip Chip Devices

Addressing the challenges associated with ever-thinner flip chip die, Henkel Electronic Materials has developed a new underfill system designed to reduce package stress through controlling die and substrate warpage. The new material, LOCTITE ECCOBOND UF 8840, is a high-performance underfill specifically designed to meet the demands of modern semiconductor flip chip devices.

Because the substrate and flip chip die have different coefficient of thermal expansion (CTE) characteristics, thermal processing (secondary reflow) can lead to either upward (“smiling”) or downward (“crying”) package warpage which may ultimately result in poor reliability. Plus, as die and substrates get even thinner, controlling warpage is becoming more critical than ever before. LOCTITE ECCOBOND UF 8840 is designed to effectively control warpage even as die thickness diminishes.

“The ability to lower stress and control warpage on today’s low profile packages is challenging at best,” comments Brian Toleno, Ph.D., Director of Global Product Management for Underfills and Encapsulants. “Being able to ensure die flatness while also delivering exceptionally high reliability isn’t easy, but LOCTITE ECCOBOND UF 8840 delivers on this requirement.”

LOCTITE  ECCOBOND UF 8840 offers compatibility with a wide variety of flux systems, has minimum resin bleed out, delivers maximum process adaptability through compatibility with both traditional needle dispensing and non-contact dispensing and has a wide dispense process window for manufacturing flexibility. LOCTITE ECCOBOND UF 8840, has been formulated to flow consistently with no voids on flip chip die up to 15mm x 15mm.  

As tested against competitive materials, LOCTITE ECCOBOND UF 8840 delivers less warpage and lower stress than other materials currently available.  Testing in an applications laboratory environment shows reduced warpage - less than 80µm on a 20mm x 20mm flip chip die with a thickness of 730µm -- and compatibility with a variety of die passivations.

“When evaluated at customer sites, LOCTITE ECCOBOND UF 8840 delivered excellent device reliability and minimal warpage-induced stress even on 155µm thick flip chip die,” concludes Toleno. “Being able to provide such outstanding performance and high reliability on much thinner die for die sizes up to 15mm x 15mm for fcCSP devices is, indeed, good news for the semiconductor packaging industry.”

For more information on LOCTITE ECCOBOND UF 8840, log onto www.henkel.com/electronics or call 714-368-8000.