Toughened epoxy for dam-and-fill encapsulation

24th March 2017

Peter Smith

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Master Bond Supreme 3HTND-2DM is a rapid curing, toughened, one part epoxy system used for the dam-and-fill method for chip-on-board encapsulation. Essentially, there are two methods to protect chips and their wire bonds. One method is referred to as glob top, where the encapsulating system is dispensed and applied directly to the area to be protected. The dam-and-fill method entails dispensing the damming material around the area to be encapsulated.

This material will cure in place and will not run, in essence forming a dam. Then an encapsulating material is applied to cover the remaining area to be protected. This system can be cured in thicknesses up to ¼ inch.

Supreme 3HTND-2DM passes ASTM E595 specifications for NASA low outgassing enabling it to be used in vacuum, aerospace, electro-optic and other related applications. This high performance compound bonds well to a wide variety of substrates used in electronics including silicon and other semiconductors, metals, ceramics and many plastics. Most importantly, Supreme 3HTND-2DM has enhanced dimensional stability and has a tensile strength of 6,000-7,500 psi at room temperature. It also maintains its Shore D hardness of 85 after withstanding 1,000 hours at 85°C/85% RH.

As a toughened system, Supreme 3HTND-2DM resists rigorous thermal cycling. It is a reliable electrical insulator and features a thermal conductivity of 10-11 BTU•in/ft²•hr•°F [1.44-1.59 W/(m·K)]. This epoxy withstands exposure to water and chemicals such as acids, bases, fuels and a number of common solvents. It is considered to have to have low ionic levels of chlorine, sodium and potassium (less than 10 ppm).

This single component system is easy to handle and offers “unlimited” working life at room temperature. It cures readily at 250°F in 20-30 minutes or 5-10 minutes at 300°F. It is serviceable from -100°F to +400°F [-73°C to +204°C]. Supreme 3HTND-2DM is available for use in syringes, cartridges and jars.