Diamond/Copper (Cu) Composite Materials for High Thermal Conductivity and Enhanced Mechanical Performance Applications
April 27, 2025
Since the 1980s, the integration level of circuits within electronic components has been increasing at a rate of 1.5 times or even faster annually. As the integration level of integrated circuits rises, the current increases accordingly, generating more heat during operation. If the heat is not dissipated in a timely manner, it can cause thermal damage to electronic components and reduce their service life. Therefore, to meet the growing heat dissipation demands of electronic components, electronic packaging materials with high thermal conductivity have been continuously researched and optimized.
Pure metals like Cu, Ag, and Al have high thermal conductivity but excessively high thermal expansion rates. Alloy materials such as Cu-W and Cu-Mo have lower thermal conductivity. Therefore, to ensure the normal operation of electronic components and prolong their lifespan, there is an urgent need to develop new packaging materials with high thermal conductivity and appropriate thermal expansion coefficients. Diamond is currently known as the hardest natural material, with a Mohs hardness of 10, and is also one of the natural materials with the highest thermal conductivity, reaching 200 to 2200 W/(m·K). Combining the thermal properties of diamond and copper, diamond/copper composites—using copper as the matrix and diamond as the reinforcement—are widely regarded as the future mainstream high-thermal-conductivity electronic packaging materials.
Diamond/Copper Composite is a high-performance composite material composed of diamond
Common preparation methods for diamond/copper composites include: powder metallurgy, high temperature and high pressure, melt infiltration, spark plasma sintering, cold spraying, and others.
(1) Powder Metallurgy
mix diamond particles with content. During the mixing process, a certain amount of binder and forming agents can be added. After pressing the mixed powders and additives into shape, sintering is carried out to obtain high thermal conductivity diamond/Cu composites. Powder metallurgy is a simple process with relatively low cost and is a relatively mature sintering technique. However, the resulting powders have low density and uneven internal microstructure. Additionally, samples prepared tend to be limited in size and simple in shape, making it difficult to directly achieve thermally superior heat conduction materials.
(2) High Temperature and High Pressure
(3) Melt Infiltration
(4) Spark Plasma Sintering (SPS)
(5) Cold Spraying
Cold spraying deposition involves placing two mixed powders into a furnace chamber, where after metal melting and liquid metal atomization, the particles are sprayed and deposited onto a substrate plate to obtain the composite material.
Strategies are employed to address the interface issues between diamond and the Cu matrix
For the fabrication of composite materials, mutual wettability between components is a necessary prerequisite for successful compounding, and it plays a crucial role in determining the interfacial structure and bonding state. The poor wettability between diamond and copper leads to a high interfacial thermal resistance. Therefore, various technical approaches have been explored to modify the diamond-Cu interface, which is critical for improving the performance of the composites.
Currently, two main strategies are employed to address the interface issues between diamond and the Cu matrix:
Surface Modification of Diamond
Coating the surface of diamond particles with active elements such as Mo, Ti, W, or Cr can significantly improve the interfacial characteristics. During sintering, these elements react with the carbon on the diamond surface to form a carbide transition layer, enhancing the wettability between diamond and the metal matrix. Furthermore, such coatings can protect the diamond structure from degradation at elevated temperatures.
Alloying of the Copper Matrix
Prior to composite processing, the copper matrix can be pre-alloyed with active elements. This pre-alloying approach produces composites with generally higher thermal conductivity. The introduction of active elements into the copper matrix effectively reduces the contact angle between diamond and copper and promotes the formation of a carbide layer at the diamond/Cu interface. These carbides, which can be partially soluble in the copper matrix, help fill interfacial voids and significantly improve thermal performance.
Market Landscape and Development Trends
Market Structure
International Leadership:
High-end markets are dominated by international players such as AMETEK (USA) and Sumitomo Electric (Japan), mainly serving the military and aerospace sectors. Heraeus (Germany) and Toho Titanium (Japan) focus on thermal management substrates for consumer electronics.
Progress in Domestic Production:
Chinese manufacturers (e.g., Institute of Metal Research, Chinese Academy of Sciences; Hunan Dingli Technology) have achieved mass production of 6-inch diamond/Cu composite substrates via powder metallurgy methods. By 2023, Chinese companies captured 25% of the domestic market share.
Market Size
According to a forecast by QY Research, the global diamond/Cu composite market is projected to reach USD 1.2 billion by 2025, with a compound annual growth rate (CAGR) of 18%. The Asia-Pacific region is expected to account for over 50% of the global demand.
In the 5G communications sector, the demand for base station thermal management modules is expected to drive a 300% increase in composite material consumption by 2024.
Future Trends
Breakthroughs in Synthetic Diamond Technologies:
The cost of chemical vapor deposition (CVD) diamonds is anticipated to drop to one-tenth of current levels within the next decade.
Heterogeneous Integration Applications:
Development of ultrathin, flexible thermal films by compounding diamond with two-dimensional materials such as graphene and boron nitride.
Smart Thermal Management:
Integration of temperature sensors into diamond/Cu substrates to enable real-time thermal distribution monitoring and dynamic thermal regulation.
Challenges and Future Research Directions
Technical Bottlenecks
Difficulty in simultaneously achieving low interfacial thermal resistance and high mass-production yields, limiting the penetration of diamond/Cu composites into consumer electronics markets.
Persistent issues with interface oxidation and elemental diffusion during long-term high-temperature service.
Research Directions
Biomimetic Interface Design:
Inspired by layered structures in nature (e.g., nacre), multi-scale reinforcement distribution strategies are being explored to optimize thermo-mechanical coupling performance.
Green Manufacturing Processes:
Development of eco-friendly processes such as cyanide-free electroplating and low-temperature sintering to reduce carbon emissions.
Ultra-High Temperature Composites:
Investigation into the application potential of diamond/Cu composites in environments exceeding 1000°C.
Conclusion
Thanks to their unparalleled thermal conductivity and comprehensive mechanical advantages, diamond/Cu composites are emerging as key materials for high-power-density electronic devices and applications under extreme conditions. Despite facing challenges in interface optimization and cost reduction, ongoing advancements in synthetic techniques and the gradual maturation of the industry chain are paving the way for broader adoption.
In the future, through interdisciplinary innovations—combining materials science, nanotechnology, and artificial intelligence—diamond/Cu composites are expected to drive electronic devices toward higher performance, miniaturization, and longer service lifespans. Furthermore, these materials will play a critical role in enhancing global energy efficiency and supporting carbon neutrality initiatives.
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