New thermal interface material for automotive and power electronics

Carbon nanotubes (CNTs) have been used for everything from inks for printed electronics to 3D printed metamaterials to photovoltaic solar panels. They are also used to create a new thermal interface material (TIM) based on aligned CNTs. The manufacturer, Carbice, is expanding into more commercial markets and introducing a new approach to the thermal design process through its Carbice Lab capability.

The mechanics of the thermally conductive and highly reliable Carbice Pad material differs from all other TIMs and allows for predictability: it is flexible like a liquid but does not dry out or crack, said CEO and Founder Baratunde Cola. Like solid TIMs, it is easy to assembleproviding predictable contact and reliable performance under stressful situations such as thermal expansion, mechanical stress, shock and vibration and over large surfaces with uneven topographies.

This material is the first TIM built from scratch specifically to solve real application problems, he said.

A specially designed thermal interface material

Cola started the company in 2011 to solve a semiconductor testing problem. “The paste material used on the back of the aluminum sheets, which had to touch every chip in the factory to test for infant mortality, had to handle robust mechanics and have good thermal properties,” he said. “But it wasn’t sturdy: it stained the back of the chips so customers would reject the whole batch thinking they were bad.” So the team developed their durable Contact Pad product for semiconductor testing.

But a US Air Force grant for TIMs in satellites that would operate at low pressure posed such a dramatic problem, involving so much hardware and such high demand, that the team focused on the satellites for 10 years, Cola said. This spurred the development of its Space Pad product, which is used in several in-orbit applications.

About two years ago, the company started testing semiconductors again. “We are now deployed to automatic test equipment handlers around the world and are growing in this market, driven in large part by automotive chip testing demands,” Cola said.

This year, Carbice will present a product for power electronics for inverters and EV transmissions. Grease and phase-change TIMs used in power modules do not retain their original performance for the 15-year automotive design requirement: over time they lose contact with the surface, lowering resistance thermal and requiring derating of the semiconductors.

Improve the thermal design process

What’s also different is the way the company does business and its focus on improving and reducing manufacturing costs, Cola said.

Creating a design with traditional TIMs requires experimenting with assembly testing and collecting data sheets for multiple materials. But specs on data sheets rarely match actual performance in real-world applications, and using traditional materials in an assembly often requires painful compromises at every step of the process.

Image courtesy of CarbiceCarbice Lab thermal interface material

Using proprietary Carbice SIM modeling software, the Carbice Lab capability allows customers to model actual application conditions of thermal interfaces to eliminate trial and error testing of multiple materials.

Carbide Lab is the world’s first simulation and evaluation capability that allows designers to design their products without trial-and-error testing of multiple TIMs, due to the predictability of the CNT material, Cola said. “Additionally, we have the experience we have accumulated over the past decade in real-world applications to correlate with first-principles physics.”

Carbice SIM, the company’s proprietary modeling software, is part of Carbice Lab. “In Carbice SIM, you can define real-world application conditions, model the real-world conditions of your interface in operation, and find the product that meets your needs,” Cola said. “This eliminates much of the cost associated with thermal design. We also perform product qualification for customers, helping them avoid production delays and cost overruns that are typical when they need to qualify new materials.”