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LOCTITE ABLESTIK 968-2

Harmonization Code : 3506.10.00.00 |   Prepared glues and other prepared adhesives, not elsewhere specified or included; products suitable for use as glues or adhesives, put up for retail sale as glues or adhesives, not exceeding a net weight of 1 kg
Main features
  • Electrically insulating
  • Hybrid chemistry
  • Dispense and Stencil print

Product Description

LOCTITE ABLESTIK 968-2 die attach adhesive is designed for microelectronic chip bonding applications. This adhesive is ideal for application by syringe dispensing or screen printing.

LOCTITE ABLESTIK 968-2 is an electrically insulating epoxy with a proprietary hybrid chemistry. It is successfully used in aerospace and defense applications, meets the requirements of MIL-STD-883, Method 5011 and can pass the NASA outgassing standard if properly cured.

Cure Schedule

  • 2 hours @ 150°C
Product Family
968-2  
EFD Syringe
3 cc 5 cc

Catalog Product

Unlike other products we offer, the products listed on this page cannot currently be ordered directly from the website.
Packaging
TDS, SDS & Technical documents

Technical Specifications

General Properties
Curing Schedule
Curing Schedule
Curing schedule is the time and temperature required for a mixed material to fully cure. While this applies to materials that cure with heat, there are also other materials that can be cured with UV.

Even though some materials can cure on ambient temperatures, others will require elevated temperature conditions to properly cure.

There are various curing schedules depending on the material type and application. For heat curing, the most common ones are Snap cure, Low temperature cure, Step cure and Staged cure.

Recommended cure type, schedule, time and temperature can always be found on the Technical data sheets.
Cure Type Heat Cure
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
Work life @25°C
Work life @25°C
Work life is the amount of time we have to work with a material until it is no longer able to be easily worked and applied on a substrate.

It is based on the change in viscosity and it can rely on the application requirements.
 96 hours
Physical Properties
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
 45,000 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)
 215 ppm
Potassium (K+)
Potassium (K+)
The amount of Potassium (K+) ion extracted from the product in parts per million (ppm)
 30 ppm
Sodium (Na+)
Sodium (Na+)
The amount of Sodium (Na+) ion extracted from the product in parts per million (ppm)
 15 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.
 35 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.
 100 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.
 139 °C
Thermal Conductivity
Thermal Conductivity
Thermal conductivity describes the ability of a material to conduct heat. It is required by power packages in order to dissipate heat and maintain stable electrical performance.

Thermal conductivity units are [W/(m K)] in the SI system and [Btu/(hr ft °F)] in the Imperial system.
 0.865 W/m.K

Additional Information

The trace below indicates a calculated “onset” of cure at about 158°C. But the cure starts below that – typically 30°C for this type of chemistry – and we know from long experience with 968-2 that the cure starts happily at 125°C.

968-2 Temperature Scan

Are you having issues with leakage? 

Even this is not to be expected, air pressure within the package could lead to some leakage in certain configurations. In this case there are some solutions that you can consider.

  1. Vent hole: The “optimum” solution is to introduce a vent-hole. Either a small hole in the package, or an incomplete dispensed ring of 968-2.  Then “plug” the hole after the 968-2 is cured. This can be done with a small amount of low temperature cure epoxy, or a UV/thermal dual-cure adhesive (eg NCA2280). Yes – the “plug” represents a potential weak point in the structure. However, it is a very small volume of material. If a filled adhesive is used, the CTE could be similar to the 968-2 and the very small volume will give low outgassing. Products like Eccobond 45 & Eccobond 104 & Stycast 2850FT might be worth a try.
  2. Optimize curing: It might be possible to optimise the 968-2 sealing with a slower of faster temperature ramp during cure. This would need to be determined experimentally. A very slow ramp rate from 25°C to the cure temperature might allow the air to diffuse through the glue, without moving the glue.
  3. Higher viscosity pastes: Products such as 968-4 with higher viscosity can help withstand the air pressure better and prevent any leakage.