Cookson Group STAYCHIP® 2078E No-Flow Fluxing Underfill

Subcategory: Adhesive; Thermoset

Material Notes:
STAYCHIP 2078E no-flow underfill is used to perform the dual functions of a solder flux and an underfill between (1) a flip chip die and a substrate or (2) an area array device and a printed circuit board. This material functions as a flux as it solders Sn63/Pb37 bumped pads to common pad metallizations (eutectic Sn/Pb, Cu/Ni/Ag, and OSP coated Cu), using a conventional reflow profile. The product also functions as an underfill as it cures during the conventional reflow profile, immediately after soldering, forming a stress absorbing, compliant matrix that distributes the stress imposed by the CTE mismatch between the die and substrate. This matrix provides enhanced environmental protection and shock resistance.

Features:

• Uses conventional reflow profile to fully cure, with no post-reflow cure needed
• Little or no voiding when the appropriate STAYCHIP no-flow underfill product is matched to the desired reflow profile
• Excellent wetting
• Cure kinetics matched to common Sn63 reflow profiles for high yield process
• Very low ionic content
• Exceptional thermal shock/impact resistance

Information provided by Cookson Electronics