LOCTITE ECCOBOND UF8806G

Harmonization Code : 3907.30.00.90 | Polyacetals, other polyethers and epoxide resins, in primary forms; polycarbonates, alkyd resins, polyallyl esters and other polyesters, in primary forms : Epoxide resins : Other

Main features

Reduced thermal stress
Superior adhesion
Excellent flow characteristics

Product Description

LOCTITE ECCOBOND UF 8806G high flow, liquid encapsulant is designed to improve the thermal cycling and reliability performance of ceramic flip chip devices. It is formulated using a proprietary Moisture Resistant Cyanate Estser (MRCE) resin.

LOCTITE ECCOBOND UF 8806G will reduce thermal stress between substrate and chip interconnects. It will form a hard black colored polymer when sufficiently cured. This material is designed to achieve JEDEC Level 1 reliability standards with ceramic substrates

Cure Schedule

45 minute ramp to 195°C + 60 minutes @ 195°C
30 minute ramp to 165°C + 180 minutes @ 165°C

Specifications
Additional Information

Technical Specifications

General Properties

Shelf Life Shelf Life Shelf life is the amount of time after manufacturing that a product is guaranteed to retain its properties. It differs vastly per product and it is based on temperature and storage conditions. The properties can be guaranteed for the temperature and time range indicated on the TDS since those are the ones tested to be the best for the product.
Shelf Life @ -40°C	365 days

Physical Properties

Thixotropic index

Thixotropic index
Thixotropic Index is a ratio of a material s viscosity at two different speeds in Ambient temperature, generally different by a factor of ten.

A thixotropic material s viscosity will decrease as agitation or pressure is increased. It indicates the capability of a material to hold its shape. Mayonnaise is a great example of this. It holds its shape very well, but when a shear stress is applied, the material easily spreads.

It helps in choosing a material in accordance to the application, dispense method and viscosity of a material.

Viscosity

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

4,500 mPa.s

Chemical Properties

Ionic Content
Chloride (Cl-) Chloride (Cl-) The amount of Chloride (Cl-) ion extracted from the product in parts per million (ppm)	10 ppm
Potassium (K+) Potassium (K+) The amount of Potassium (K+) ion extracted from the product in parts per million (ppm)	10 ppm
Sodium (Na+) Sodium (Na+) The amount of Sodium (Na+) ion extracted from the product in parts per million (ppm)	10 ppm

Thermal Properties

Coefficient of Thermal Expansion (CTE) Coefficient of Thermal Expansion (CTE) CTE (Coefficient of thermal expansion) is a material property that is indicative of the extent to which a material expands with a change in temperature. This can be a change in length, area or volume, depending on the material. Knowing the CTE of the layers is helpful in analyzing stresses that might occur when a system consists of an adhesive plus some other solid component.
Coefficient of Thermal Expansion (CTE), α1 Coefficient of Thermal Expansion (CTE), α1 CTE α1 (alpha 1) is the slope of the Coefficient of thermal expansion in a temperature range below the Glass transition temperature (Tg). It explains how much a material will expand until it reaches Tg.	27 ppm/°C
Coefficient of Thermal Expansion (CTE), α2 Coefficient of Thermal Expansion (CTE), α2 CTE α2 (alpha 2) is the slope of the Coefficient of thermal expansion in a temperature range above the Glass transition temperature (Tg). It explains the extent to which a material will expand after it passes Tg.	97 ppm/°C

Glass Transition Temperature (Tg)

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.

136 °C

Additional Information

Is there a recommended method for die depopulation?

We do not know of any “magic trick” or any easy process to remove packages with these underfills. UF8806G is based on Cyanate Ester chemistry, so it is different to epoxies such as UF3915 even though both products are very robust, and are designed to form a permanent bond.

There are no “solvents” that will easily dissolve the resin. Some acids should attack it (a heated mixture of concentrated Nitric + Sulphuric acid could work) but it is very hazardous and will also attack the board/substrate.

The only practical way to remove the packages (or chips) is to heat up to around 250°C (or at least sufficiently hot to melt the solder) and either twist the package or prise it upward to peel it away from the board/substrate.