Smartphones, electric vehicles (EVs), and high-performance industrial equipment—electronic devices around us are advancing every year, with increased performance and further miniaturization. As a result, the amount of heat generated inside these devices is also increasing, making effective thermal management more important than ever before. If heat is not properly dissipated, it leads to raising of internal temperatures, reduced performance, malfunctions, and even a shorter product lifespan. To address these challenges, effective thermal design and the use of advanced heat-dissipating materials have become essential.

The Role and Importance of Thermal Interface Materials (TIMs)

There are various methods for thermal management in electronic devices, such as heat sinks, fans, and liquid cooling systems. Among these, thermal interface materials (TIMs) play a crucial role in effective heat dissipation.

TIMs are thermally conductive materials that are inserted between heat-generating components such as ICs (integrated circuits) or power devices and heat-dissipating components like heat spreaders or heat sinks. By filling in the microscopic gaps and surface irregularities between the heat source and the cooling component, TIMs create an efficient thermal pathway that allows heat to be transferred out of the device more effectively.

Thermal Conductive Fillers — The Key to TIM Performance

The main components of TIMs are typically polymers such as silicone or epoxy. However, these resins themselves have low thermal conductivity and, on their own, cannot provide sufficient heat dissipation. By incorporating a high concentration of thermally conductive fillers, the overall thermal conductivity of the TIM can be greatly improved, enabling efficient heat transfer. Selecting the right type of filler and optimizing its formulation are crucial factors that determine the cooling performance of TIMs.

Required Properties of Thermal Conductive Fillers

Fillers commonly used in TIMs include aluminum nitride (AlN) and boron nitride (BN). The following properties are required for these fillers:

1. High Thermal Conductivity
In order to achieve effective thermal management, it is essential for the filler material to have high thermal conductivity.

2. Electrical Insulation
Due to electronic devices have densely packed circuits, it is important to prevent short circuits and leakage by using materials with excellent insulating properties.

3. Appropriate Density
The filler should have a density suitable for the specific TIM application, maintaining a balance between lightweight construction and heat dissipation performance.

4. High Packing Fraction (High Fillability)
The achievable packing fraction is determined by the particle shape and particle size distribution design.

• Particle Shape (Spherical vs. Polyhedral Particles)
  Spherical particles: These can be filled in and dispersed closely together, allowing for high fill ratios when mixed into TIMs or thermal resins. A higher packing fraction provides more continuous heat paths, resulting in improved thermal conductivity.
  Polyhedral particles: These have larger contact areas between particles, delivering high performance in applications such as heat-dissipating substrates.

• Particle Size and Formulation
  By blending both large and small filler particles in an optimal ratio, it is possible to achieve a high fillability and improved flowability, thereby enhancing the overall thermal conductivity of the TIM.

• Large particle size (approximately 50–80 μm):
  These are considered large filler particles and contribute to improving thermal conductivity. However, they tend to create more gaps between particles.

• Small particle size (approximately 1–10 μm):
  These are typical sizes for fillers and offer excellent packing ability, making it easier to form a uniform TIM layer. The more contact points there are between filler particles, the more continuous heat transfer pathways (heat paths) can be established.

5.Surface Treatment
Aluminum nitride (AlN) fillers are highly hydrophilic, so hydrophobic surface treatments—such as silane coupling—are applied to improve compatibility with resins. It is important to select an appropriate surface treatment according to the polymer being used (such as epoxy or silicone).

Why Aluminum Nitride (AlN) Fillers Are Ideal for TIMs

There are various types of thermally conductive fillers used in thermal interface materials (TIMs). When comparing the properties of each material, aluminum nitride (AlN) stands out as an excellent choice for heat-dissipating applications due to its outstanding balance of high thermal conductivity, electrical insulation, and suitable density.

Comparison Table of Representative Fillers

Aluminum Nitride Fillers Offered by Matsuo Sangyo

At Matsuo Sangyo, we offer spherical aluminum nitride (AlN) fillers that are ideally suited for use in thermal interface materials (TIMs) and other heat-dissipating resin applications. These fillers possess the following features and contribute to enhanced performance in thermal management design.

Main Features

-Spherical particles with a maximum particle size of 80 μm

-Achieves high packing density and features a structure that excels in forming effective

thermal conduction paths.

Achieves Both High Thermal Conductivity and High Electrical Insulation
Delivers the balanced performance required for TIMs, ensuring excellent reliability.

Thermal Conductivity: 170 W/m·K (RT, sintered body)
A high-performance material that greatly improves heat dissipation efficiency.

Custom Surface Treatment Available
Optimized dispersibility and adhesion for different applications, such as silicone or epoxy systems.

Main Applications:

• TIMs (thermal interface sheets, thermal grease, etc.)
• Semiconductor encapsulation resins
• And more

For inquiries about aluminum nitride fillers, click here

Related Products：

For more information on TIMA 5, the optimal evaluation system for thermal performance testing of TIMs, click here.

Matsuo Sangyo’s “Thermal” Solutions

At Matsuo Sangyo, we support the advancement of high-performance heat-dissipating materials, focusing on aluminum nitride (AlN) fillers that combine high thermal conductivity with excellent electrical insulation.
Beyond providing advanced materials, we also offer testing and analysis using the Thermal Interface Material Analyzer TIMA 5, enabling comprehensive evaluation of TIM thermal performance.

Our demo room, conveniently located just a 5-minute walk from Shin-Yokohama Station, is equipped for hands-on evaluation of your samples with the TIMA 5 system. Here, you can verify the performance of your TIMs under actual operating conditions.

If you are facing any thermal management challenges, please feel free to contact us for consultation.

For demo and products inquiry, you can click here