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6CCVD Research

Research progress in interface optimization and preparation technology of high thermal conductivity diamond/copper composite materials

At a Glance

Section titled “At a Glance”
MetadataDetails
Publication Date2025-04-24
JournalFrontiers in Materials
AuthorsYaohui Xue, Rui Li, Yan Deng, Zhuo Zhang, Jing Chen
Citations1
AnalysisFull AI Review Included

Executive Summary

Section titled “Executive Summary”

This review analyzes strategies for optimizing high thermal conductivity (HTC) diamond/copper (Dia/Cu) composites, critical for next-generation electronic packaging.

  • Core Challenge: The practical performance of Dia/Cu is limited by high Interfacial Thermal Resistance (TBR > 10-7 m2K/W) resulting from poor interfacial bonding between the ceramic diamond and the metallic copper matrix.
  • Interfacial Solution: TBR is minimized through two synergistic engineering approaches: diamond surface metallization (e.g., TiC, WC, Cr coatings) and copper matrix alloying (e.g., Zr, B, Cr additions).
  • Performance Targets: The goal is to achieve thermal conductivity (Îș) greater than 900 W/mK and reduce TBR to less than 5 x 10-8 m2K/W by establishing coherent carbide interlayers.
  • Key Achievements: Record Îș of 930 W/mK was achieved in Cu-0.5Zr composites via melt infiltration, utilizing discontinuous ZrC nanostructures (2-5 nm thick) for acoustic impedance matching.
  • Fabrication Optimization: Optimal composite performance requires precise control over diamond morphology (particle size > 400 ”m, volume fraction 60-70 vol%) and sintering conditions (e.g., temperature < 1,050 °C to prevent graphitization).
  • Future Direction: Research is focused on hybrid strategies and multiscale architectures to surpass the 1,000 W/mK threshold, bridging lab-scale innovation with industrial scalability.

Technical Specifications

Section titled “Technical Specifications”
ParameterValueUnitContext
Target Thermal Conductivity (Îș)> 900W/mKRequired threshold for next-generation thermal management.
Achieved Îș (Record)930W/mKCu-0.5Zr composite via Melt Infiltration (ZrC acoustic matching).
Achieved Îș (VMEP)846.5W/mKVacuum Micro-Evaporation Plating (VMEP) on 400 ”m diamond particles.
Achieved Îș (HPHT)742W/mK70 vol% Dia, sintered at 4.5 GPa and 1,200 °C.
Target Interfacial Thermal Resistance (TBR)< 5 x 10-8m2K/WGoal for optimized interfaces.
Unmodified TBR (Bottleneck)> 10-7m2K/WTypical resistance for pristine diamond/copper interfaces.
Optimal Diamond Volume Fraction60-70vol%Establishes low-resistance percolation pathways.
Optimal Diamond Particle Size> 400”mMinimizes interfacial scattering sites per unit volume.
Optimal ZrCx Interphase Thickness2-5nmDiscontinuous nanostructures (0.5 wt% Zr alloying).
Diamond Intrinsic Îș1,200-2,000W/mKExtreme anisotropic thermal conductivity.
Diamond CTE≈ 1 x 10-6K-1Ultralow Coefficient of Thermal Expansion.
Sintering Temperature Limit< 1,050°CRequired to inhibit diamond graphitization.

Key Methodologies

Section titled “Key Methodologies”

The fabrication and optimization of Dia/Cu composites rely on precise control of interfacial chemistry and consolidation parameters:

  1. Diamond Surface Metallization:

    • Electroless Plating (ELP): Chemical deposition of metal ions (e.g., Cu) onto pre-treated diamond surfaces (e.g., thin TiC layer via molten salt). Limited by poor adhesion (<50 MPa).
    • Magnetron Sputtering (MS): Physical vapor deposition of carbide-forming elements (e.g., W, Cr) in a low-pressure argon plasma to form uniform coatings (e.g., 45-300 nm thickness).
    • Molten Salt Coating (MSC): Diffusion-driven reaction in chloride-based salt baths (600 °C-900 °C) to form chemically bonded carbide layers (e.g., Mo2C or Cr7C3).
    • Vacuum Micro-Evaporation Plating (VMEP): Low-temperature synthesis (<500 °C) of interfacial compounds under vacuum, promoting coherent phonon transport.

  2. Matrix Alloying:

    • Gas Atomization: Synthesis of modified Cu alloy powders (e.g., Cu-Zr, 0.25-1.0 wt% Zr) through high-velocity inert gas fragmentation of molten streams.
    • Alloy Smelting: Thermochemical synthesis of modified Cu matrices (e.g., Cr-B) prior to infiltration, enabling precise control over carbide precipitation (e.g., discrete CrB2 nanostructures).

  3. Consolidation Techniques:

    • Vacuum Hot-Press Sintering (VHPS): Solid-state diffusion under vacuum (<10-3 Pa) and uniaxial pressure (20-100 MPa), typically at 900 °C.
    • High-Temperature High-Pressure (HPHT) Sintering: Utilizes extreme conditions (3-6 GPa, 1,000 °C-1,300 °C) to achieve ultra-dense composites (>99.5% density) by inhibiting graphitization.
    • Spark Plasma Sintering (SPS): Rapid densification (up to 500 °C/min) using pulsed direct currents and pressure (30-100 MPa), often used for integrating ZrC/Zr bilayer coatings at 850 °C.
    • Melt Infiltration (MI): Driving molten metal (often alloyed Cu) into diamond beds using external pressure (1-15 MPa), leveraging capillary forces and particle size synergies.

Commercial Applications

Section titled “Commercial Applications”

The research focuses on materials designed to overcome thermal bottlenecks in high-performance systems, enabling greater power density and reliability.

  • High-Power Electronics and Microelectronics: Essential for thermal management in miniaturized and integrated circuits where heat fluxes exceed 1 kW/cm2.
  • Advanced Electronic Packaging: Fabrication of high-performance heat sinks, substrates, and thermal spreaders for CPUs, GPUs, and power modules.
  • High-Frequency/RF Devices: Applications requiring materials with matched thermal expansion (low CTE, ≈ 1 x 10-6 K-1) to minimize thermal stress and ensure device reliability during operation.
  • Aerospace and Defense Systems: Components requiring lightweight materials with exceptional thermal dissipation capabilities under extreme operating conditions.
  • Solid-State Lighting (SSL): High-brightness LED and laser diode packaging where efficient heat removal is critical for maintaining light output and lifespan.
View Original Abstract

With the miniaturization and integration of microelectronic components, the demand for high-thermal-conductivity electronic packaging materials has grown substantially. Diamond/copper (Dia/Cu) composites have become a focus of research due to their ultra-high thermal conductivity and low coefficient of thermal expansion. However, poor interfacial bonding and high interfacial thermal resistance between diamond and copper limit their practical performance. This paper reviews strategies to enhance interfacial bonding, including diamond surface metallization (e.g., electroless plating, magnetron sputtering, molten salt method, vacuum electroplating, and embedding) and copper matrix alloying (e.g., gas atomization and alloy smelting), and evaluates their effects on thermal transport properties. Additionally, the influence of preparation processes—such as vacuum hot-pressing sintering, high-temperature high-pressure sintering, spark plasma sintering, and melt infiltration on the microstructure and thermal conductivity of composites are discussed. Key factors including diamond surface roughness, particle size, volume fraction, and sintering conditions (e.g., temperature, pressure, and dwell time) are analyzed. Experimental and computational studies demonstrate that systematic optimization of these factors enhances the thermal conductivity of Dia/Cu composites, providing critical insights for developing next-generation high-performance electronic packaging materials.

Tech Support

Section titled “Tech Support”

Original Source

Section titled “Original Source”

References

Section titled “References”
  1. 2018 - High thermal conductivity of Cu-B/diamond composites prepared by gas pressure infiltration [Crossref]
  2. 2013 - Effect of sintering parameters on the microstructure and thermal conductivity of diamond/Cu composites prepared by high pressure and high temperature infiltration [Crossref]
  3. 2013 - On the thermal conductivity of Cu-Zr/diamond composites [Crossref]
  4. 2017 - Design of interfacial Cr3C2 carbide layer via optimization of sintering parameters used to fabricate copper/diamond composites for thermal management applications [Crossref]
  5. 2024 - Enhancing interfacial heat conduction in diamond-reinforced copper composites with boron carbide interlayers for thermal management [Crossref]
  6. 2020 - Research progress of diamond/copper composites with high thermal conductivity [Crossref]
  7. 2010 - Microstructure and thermal properties of diamond/aluminum composites with TiC coating on diamond particles [Crossref]
  8. 2016 - Functionalized graphite nanoplatelets/epoxy resin nanocomposites with high thermal conductivity [Crossref]
  9. 2022 - Enhanced interfacial bonding in copper/diamond composites via deposition of nano-copper on diamond particles [Crossref]
  10. 2015 - Interfacial characteristics of diamond/aluminum composites with high thermal conductivity fabricated by squeeze-casting method [Crossref]

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