Thermally Conductive Insulators For 3D Integrated Circuits

Thermally Conductive Insulators

As electronic devices become more compact, they generate more heat and need a reliable way to distribute and expel it. High thermal conductivity insulators help maintain operational temperatures by channeling excess heat to cooling channels, allowing transistors and other components to function at optimal temperatures without overheating. This critical technology also plays a pivotal role in advancing 3D integrated circuit technologies (ICs), where managing heat within tightly packed transistor layers presents unique challenges.

The Power of Thermally Conductive Insulators conductivity of a material measures its ability to transfer heat by convection or radiation. It is a logarithmic scale, with low values indicating high insulation and high values indicating good conductivity. The thermal conductivity of air is 1.0 watts per meter-kelvin (W/mK).

As temperature increases, the thermal conductivity of a material decreases. This is because the number of free electrons in a material decreases with temperature. In a pure metal, such as gold or silver, the conductivity is high because the number of free electrons is large, but in alloys, such as those made with copper, the conductivity is low because the number of free electrons is small.

In electronic applications, thermally conductive insulators provide the perfect balance of conductivity and electrical insulation. This helps minimize the potential for overheating-related failures that can compromise device performance or lifespan.

Bergquist SIL PAD insulation products are designed to meet demanding industrial and consumer applications, including thermal management of high-density transistors in 3D ICs. They are available in a variety of thicknesses and can be cut to the desired length with standard tools. In addition, they can be printed to support a fully automated pick and place process.

In a typical application, the insulator is placed over the bare metal surface of a printed circuit board. It is then bonded to the circuit board using an epoxy that is both strong and thermally conductive. This provides a clean, grease-free surface for printing and enables efficient cooling of sensitive transistors.

Increasingly, the size and power of electronic devices have reached physical limits that create new challenges for effective thermal management. In 3D ICs, the thermal management challenge is compounded because heat can dissipate faster in thin, densely stacked transistor layers than in traditional 2D ICs. This leads to high power densities and localized hot spots in 3D IC tiers that require enhanced thermal transfer through the inter-layer interfaces to cool the tiers down to safe operating temperatures.

To address these challenges, innovative fabrication techniques are being developed to improve the thermal conductivity of insulators. For example, additive manufacturing allows for unprecedented control of the microstructure of insulator materials, while aeolotropism fillers are being used to improve the thermal conductivity of ceramic-based insulators. These innovations are helping to ensure that 3D ICs can be built without compromising transistor efficiency or longevity. This is key to sustaining  Thermally Conductive Insulators and expanding the capabilities of electronic devices in areas such as medical and automotive applications, as well as providing new opportunities for 3D integration across multiple industries.