The era of 5G brings massive data traffic that demands higher specifications for communication terminal components such as chips and antennas. This significant increase in power consumption leads to a dramatic rise in heat generation in these areas. Thermal management materials are highly effective for dissipating heat in various fields, including 5G射频 chips, millimeter-wave antennas, wireless charging, wireless transmission, IGBTs, printed circuit boards, AI, and the Internet of Things, and are indispensable.
What is thermal management?
Thermal Management, as the name implies, is the management of "heat." It is widely used in various fields of the national economy, controlling the dispersion, storage, and conversion of heat within systems. Advanced thermal management materials form the material foundation of thermal management systems, with thermal conductivity being the core technical indicator of all thermal management materials.
When microelectronic materials or devices are joined together, the actual contact area is only 10% of the macroscopic contact area, with the remainder being gaps filled with air. Since the thermal conductivity of air is less than 0.03 W/(m·K), it is a poor conductor of heat, which can reduce the system's scattering efficiency. Filling these gaps with thermal interface materials (TIMs) that have high thermal conductivity and ductility can establish gapless contact between microelectronic devices and heat sinks, significantly reducing contact thermal resistance.
Ideal TIM materials should possess the following characteristics: 1. High thermal conductivity to reduce the thermal resistance of the interface material itself; 2. High flexibility to ensure that the interface material can fully fill the gaps of the contact surface under low installation pressure, ensuring a minimal thermal resistance between the interface material and the contact surface; 3. Insulation properties; 4. Easy installation and removability; 5. Broad applicability, capable of filling both small gaps and large spaces.
Polymers are known for their high flexibility and insulating properties, making them widely used in thermal interface materials. However, high thermal conductivity is a must for thermal interface materials. Traditional polymers and rubber materials generally have low thermal conductivity. Adding inorganic fillers such as alumina, aluminum nitride, silicon carbide, boron nitride, and carbon nanotubes can effectively improve the thermal conductivity of polymers. The issue that has always been present, though, is that the addition of inorganic fillers makes the polymer materials脆 and hard, reducing their workability and flexibility—essentially nullifying the advantages of polymers as highly workable materials. To date, there is no ideal solution internationally or domestically for this decline in material flexibility. The common approach is to use polymer matrices with the highest flexibility possible, while also striving to find a good balance between maintaining flexibility and achieving high thermal conductivity.
As the 5G era emerges, there's a pronounced trend towards high power, high integration, and high heat, making thermal management a "hard necessity" for smartphones.
Since 2022, 5G technology has been advancing in various aspects, with consumer electronics accelerating their development towards high power, high integration, thinness, and intelligence. Due to the continuous rise in integration, power density, and assembly density, electronic devices in the 5G era have seen their performance improve while their operating power consumption and heat output soar dramatically. Statistics show that material failure caused by thermal concentration accounts for 65% to 80% of the total failure rate. To prevent device failure due to overheating, technologies such as thermal grease, thermal gel, graphite heat sinks, heat pipes, and heat spreaders (VC) have emerged and evolved continuously. Thermal management has become a "must-have" for 5G era electronic devices.
Section 3: Recent Advances in Thermal Management Materials
Polymer-based thermal conductive materials primarily focus on the research of filled thermal conductive polymers. The polymer matrices commonly used for thermal interface materials include organic silicon, epoxy resin, polyurethane, and others. The types of thermal fillers mainly consist of: (1) carbon-based, such as amorphous carbon, graphite, diamond, carbon nanotubes, and graphene; (2) ceramic-based, including boron nitride (BN), aluminum nitride (AlN), silicon nitride (Si3N4), silicon carbide (SiC), magnesium oxide (MgO), aluminum oxide (Al2O3), and silicon dioxide (SiO2). The addition amount, shape, size, mixing ratio, surface treatment, orientation, agglomeration, and network structure of the fillers all significantly affect the thermal conductivity of polymer-based thermal conductive materials. Currently, researchers are primarily concentrating on designing new polymer/filler composite materials, primarily through optimizing the intrinsic chemical/physical structure of thermal fillers and constructing three-dimensional networks of thermal fillers to enhance the thermal conductivity of polymer composites.
