ECCOBOND FP4546

Harmonization Code : 3910.00.00.90 | Silicones in Primary Forms; Others

ECCOBOND FP4546

Main features

  • Low-CTE Flip-Chip Underfill
  • Toughened Crack-Resistant Epoxy
  • 32-Hour Pot Life at 25 deg C

Product Description

LOCTITE ECCOBOND FP4546 is a black, heat-curing liquid epoxy encapsulant developed for semiconductor underfill and flip-chip devices. Its high-purity, filled formulation combines a low coefficient of thermal expansion with improved toughness and is specially suited to assemblies requiring improved crack and fracture resistance. After cure, it forms a rigid, low-stress seal that dissipates stress on solder joints. The material supports capillary underfill processing, with a typical viscosity of 12,000 mPa·s at 25 °C and a recommended cure of 30 minutes at 165 °C or 90 minutes at 150 °C.

Key features

  • Low thermal expansion: Typical cured CTE is 35 ppm/°C below the glass transition temperature.
  • Toughened encapsulation: Developed for improved crack and fracture resistance in flip-chip devices.
  • Controlled heat cure: Recommended cure is 30 minutes at 165 °C, with an alternate schedule of 90 minutes at 150 °C.

Applications / Suitable for

  • Flip-chip device underfill
  • Semiconductor encapsulation
  • Capillary underfill processes
Product Family

ECCOBOND FP4546

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TDS, SDS & Technical Documents

Technical Specifications

Physical Properties
Viscosity
Viscosity is a measurement of a fluid’s resistance to flow. Viscosity is commonly measured in centiPoise (cP). One cP is defined as the viscosity of water and all other viscosities are derived from this base. MPa is another common unit with a 1:1 conversion to cP. A product like honey would have a much higher viscosity -around 10,000 cPs- compared to water. As a result, honey would flow much slower out of a tipped glass than water would. The viscosity of a material can be decreased with an increase in temperature in order to better suit an application
12000 mPa.s
General Properties
Filler Content
60 %
Pot Life
Pot life is the amount of time it takes for the viscosity of a material to double (or quadruple for lower viscosity materials) in room temperature after a material is mixed. It is closely related to work life but it is not application dependent, less precise and more of a general indication of how fast a system is going to cure.
32 hours
Thermal Properties
Glass Transition Temperature (Tg)
The glass transition temperature for organic adhesives is a temperature region where the polymers change from glassy and brittle to soft and rubbery. Increasing the temperature further continues the softening process as the viscosity drops too. Temperatures between the glass transition temperature and below the decomposition point of the adhesive are the best region for bonding. The glass-transition temperature Tg of a material characterizes the range of temperatures over which this glass transition occurs.
130 °C

Additional Information

Technical properties

As-supplied / before-processing properties

Typical uncured-material and storage values provided for product evaluation. These values are reference data and are not guaranteed specifications.

Property Value Unit Method / condition
Appearance Black liquid — As supplied
Viscosity 12,000 mPa·s Brookfield cone and plate, CP52, 25 °C, 20 rpm
Filler content 60 % Ignition method
Flow time 30 s 90 °C, 3 mil gap, 500 mil flow
Pot life 32 h 25 °C; time to double viscosity
Gel time 10 min 121 °C
Shelf life 270 days Stored at −40 °C
Technical properties

After-processing / final-state properties

Typical cured-material values provided for technical evaluation. Cure and test conditions are retained where supplied; values are not guaranteed specifications.

Property Value Unit Method / condition
Coefficient of linear thermal expansion below Tg 35 ppm/°C Sample cured 7 minutes at 160 °C
Coefficient of linear thermal expansion above Tg 100 ppm/°C Sample cured 7 minutes at 160 °C
Glass transition temperature 130 °C Typical cured-material value
Flexural modulus 7,500 N/mm² Equivalent to 1.09 × 106 psi
Extractable chloride 20 ppm Extractable ionic content
Extractable sodium 5 ppm Extractable ionic content

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