Heat-resistant silicone pottants for advanced power modules

21st May 2019

DOW

Alex Lynn

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A global specialist in silicones and silicon-based technology, Dow, has further expanded its portfolio of protective pottants with the launch of new, heat-resistant dielectric gels under the DOWSIL label: EG-4000, EG-4100 and EG-4120. The latest additions are thermally stable silicone pottants for protective encapsulation of sensitive components within SiC and GaN power modules, on PCBs and in industrial sensors and actuators.

Dow’s three new silicone gels exhibited no cracking or delamination after accelerated ageing at 215°C for 3,000 hours in an air oven, and their dielectric strength and mechanical properties remained stable throughout testing.

Rogier Reinders, Global Marketing Director for Dow Performance Silicones, said: “Component miniaturisation and the growing adoption of power modules based on compound semiconductors are familiar trends in multiple industries, but the end result is the same for module manufacturers: Their compact designs need to deliver ever-higher power densities and ensure reliable protection of components despite the rising internal temperatures that result.

“The addition of these three new high-heat resistant silicones to our dielectric gel portfolio aims to help Dow customers stay ahead of these challenging trends, and cost-effectively meet demand for their next-generation devices.”

All of the new Dow gels are two-part, low-viscosity formulations that enable good wetting, and cure within 60 minutes at 150°C for efficient processing. After cure, they deliver dielectric insulation for the dies and interconnects within power modules and protect them from the harmful effects of moisture and other environmental contaminants.

Like other silicone gels in Dow’s portfolio, the new products also provide outstanding stress release from thermal and mechanical stresses.

Dow’s new gels range in firmness after cure to help designers find the right solution for their application:

DOWSIL EG-4000 Dielectric Gel cures to form a comparatively softer material (with a hardness of 70g) for highly demanding stress-release applications. It maintains reliable performance at operating temperatures ranging from -60 to +215°C.
DOWSIL EG-4100 and DOWSIL EG-4120 Dielectric Gels cure to form toughened protective pottants, delivering hardnesses of 250g and 380g respectively. Both are self-priming gels that offer increased resistance to delamination under thermal cycling. They deliver reliably consistent performance at operating temperatures ranging from -40 to +215°C.