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

At a Glance

Metadata	Details
Publication Date	2025-04-24
Journal	Frontiers in Materials
Authors	Yaohui Xue, Rui Li, Yan Deng, Zhuo Zhang, Jing Chen
Citations	1
Analysis	Full AI Review Included

Research Progress in High Thermal Conductivity Diamond/Copper Composites: A 6CCVD Technical Analysis

Executive Summary

This technical review analyzes advancements in diamond/copper (Dia/Cu) composite fabrication, focusing on strategies to overcome the critical thermal bottleneck—high Interfacial Thermal Resistance (TBR).

Application Focus: Dia/Cu composites are essential for next-generation high-power microelectronics thermal management, requiring thermal conductivities ($\kappa$) exceeding 900 W m^-1 K^-1.
Core Challenge: Weak diamond-copper bonding results in high TBR (> 10^-7 m² K W^-1), severely degrading composite performance via phonon scattering.
Interface Solution: Successful strategies involve synergistic optimization through diamond surface metallization (e.g., TiC, W, ZrC interlayers) and copper matrix alloying (e.g., Zr, B).
Performance Benchmark: Record thermal conductivity of 930 W m^-1 K^-1 was achieved using ZrC-induced acoustic impedance matching via melt infiltration techniques.
Material Requirements: Maximizing thermal transport requires precise control over diamond morphology, specifically large particle sizes (>400 µm), high volume fractions (60-70 vol%), and carbide interlayer thickness (50-100 nm).
6CCVD Value Proposition: 6CCVD supplies the high-purity Polycrystalline Diamond (PCD) and custom metalization services necessary to achieve the precise interfacial engineering required for these ultra-high performance thermal solutions.

Technical Specifications

The following table summarizes the critical material parameters and performance metrics extracted from the research on high thermal conductivity Dia/Cu composites.

Parameter	Value	Unit	Context
Target Thermal Conductivity ($\kappa$)	> 900	W m^-1 K^-1	Threshold for next-generation thermal management
Record Achieved $\kappa$	930	W m^-1 K^-1	Cu-0.5Zr composite via Melt Infiltration (ZrC matching)
Intrinsic Diamond $\kappa$ (SCD)	1,200 - 2,000	W m^-1 K^-1	Anisotropic thermal conductivity
Critical TBR Bottleneck	> 10^-7	m² K W^-1	Weak diamond-Cu interface (requires mitigation)
Optimized TBR Target	< 5 x 10^-8	m² K W^-1	Required for industrial viability and high performance
Optimal Carbide Layer Thickness	50 - 100	nm	Required for lattice mismatch stress relief and phonon matching
Critical Diamond Particle Size	> 400	µm	Minimizes interfacial scattering sites per unit volume
Optimal Diamond Volume Fraction	60 - 70	vol%	Establishes low-resistance percolation pathways
HPHT Sintering Pressure Range	3 - 6	GPa	Used to achieve ultra-dense composites (>99.5% density)
Maximum Sintering Temperature	< 1,050	°C	Required to inhibit diamond graphitization

Key Methodologies

The research identifies several advanced methodologies critical for optimizing the microstructure and thermal transport properties of diamond/copper composites.

Diamond Surface Metallization:
- Goal: Deposit continuous carbide-forming elements (W, Mo, Cr, Ti) to create a chemically bonded interlayer, enhancing wettability and reducing TBR.
- Techniques: Electroless Plating (ELP), Magnetron Sputtering (used for 45-300 nm W coatings), Molten Salt Coating (MSC), and Vacuum Micro-Evaporation Plating (VMEP).
Matrix Alloying:
- Goal: Introduce active elements (e.g., Zr, B, Cr) into the copper matrix prior to composite fabrication.
- Mechanism: During thermal processing, these elements diffuse to the diamond interface, forming epitaxial carbide transition layers (e.g., discontinuous ZrC nanostructures 2-5 nm thick) that facilitate acoustic impedance matching.
Consolidation Processes:
- Melt Infiltration: Highly effective method leveraging capillary forces and external pressure (1-15 MPa) to achieve high density and the highest reported thermal conductivities (up to 930 W m^-1 K^-1).
- Vacuum Hot-Press Sintering: Integrates thermal activation and uniaxial pressure (20-100 MPa) in a vacuum environment (<10^-3 Pa) to promote solid-state diffusion.
- HPHT Sintering: Utilizes extreme pressure (3-6 GPa) and temperature (1,000 °C-1,300 °C) to achieve ultra-dense composites, though limited by high cost and scalability.
Morphological and Sintering Parameter Control:
- Particle Size: Use of large diamond particles (>400 µm) is critical to reduce interfacial defect density.
- Temperature Control: Sintering temperatures must be strictly controlled below 1,050 °C to prevent thermal degradation and graphitization of the diamond phase.

6CCVD Solutions & Capabilities

6CCVD is uniquely positioned to support researchers and engineers replicating and advancing the high-performance Dia/Cu composite technology described in this paper. Our MPCVD diamond materials and custom fabrication services directly address the critical requirements for interface optimization and large-scale production.

Research Requirement	6CCVD Solution & Capability	Technical Advantage
High-Purity Diamond Reinforcement	Optical Grade PCD Plates/Wafers	Provides the high intrinsic thermal conductivity (up to 2,000 W m^-1 K^-1) and purity necessary for achieving the target >900 W m^-1 K^-1 composite performance.
Custom Dimensions & Scaling	Plates/Wafers up to 125mm (PCD)	Supports the fabrication of large-scale heat sinks and electronic packaging components, overcoming the dimensional limitations (<50 mm) noted in methods like SPS.
Interface Engineering (Metallization)	In-House Custom Metalization Services	We offer precise deposition of Au, Pt, Pd, Ti, W, and Cu. This capability is essential for replicating the critical carbide interlayer formation (e.g., TiC, WC, ZrC precursors) required for TBR reduction (<10^-8 m² K W^-1).
Surface Finish and Morphology	Advanced Polishing (Ra < 5nm for PCD)	While the paper explores roughening, 6CCVD provides highly controlled surface finishes, allowing researchers to precisely tune the surface state for optimal carbide nucleation and adhesion, or to utilize smooth SCD (Ra < 1nm) for thin-film applications.
Specialized Materials	Boron-Doped Diamond (BDD) Availability	BDD materials can be supplied for electrochemical studies related to matrix alloying and interface chemistry, or for applications requiring conductive diamond components.
Engineering Support	In-House PhD Material Science Team	Our experts provide consultation on material selection, optimal thickness (SCD: 0.1µm - 500µm; PCD: 0.1µm - 500µm), and processing compatibility for similar high thermal conductivity electronic packaging projects.

For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.

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

Original Source

DOI: https://doi.org/10.3389/fmats.2025.1582990

References

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