High thermal conductive copper/diamond composites - state of the art
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2020-10-20 |
| Journal | Journal of Materials Science |
| Authors | S. Q. Jia, Fei Yang |
| Institutions | University of Waikato |
| Citations | 82 |
| Analysis | Full AI Review Included |
High Thermal Conductive Copper/Diamond Composites: 6CCVD Technical Analysis
Section titled âHigh Thermal Conductive Copper/Diamond Composites: 6CCVD Technical AnalysisâThis document analyzes the research paper âHigh thermal conductive copper/diamond composites: state of the artâ (J Mater Sci (2021) 56:2241-2274) to highlight critical material requirements and demonstrate how 6CCVDâs MPCVD diamond products and customization services directly support and advance this high-power thermal management research.
Executive Summary
Section titled âExecutive Summaryâ- Application Focus: Copper/Diamond (Cu/Dia) composites are the next-generation material solution for high-power electronic heat sinks, offering Thermal Conductivity (TC) exceeding 500 W/(m K).
- Performance Bottleneck: The primary challenge is the poor chemical affinity between copper and diamond, leading to low Interfacial Thermal Conductance (ITC, $h_{c}$).
- Interface Engineering: High TC is achieved by engineering a carbide-forming interfacial layer (e.g., TiC, B${4}$C, Cr${7}$C$_{3}$) using elements like Ti, Cr, W, B, or Zr, which acts as a thermal bridge between the diamond reinforcement and the copper matrix.
- Material Requirement: Achieving maximum composite TC relies on using high-quality synthetic diamond particles with intrinsic TC up to 2200 W/(m K) and precise surface modification.
- Optimization Factors: Key factors influencing ITC include interfacial layer thickness (optimal range: tens to hundreds of nm), surface roughness, atomic intermixing, and chemical bonding strength.
- Processing Methods: The paper reviews successful fabrication via Vacuum Hot Pressing (VHP), Spark Plasma Sintering (SPS), Metal Infiltration, and High-Temperature High-Pressure (HTHP) methods.
Technical Specifications
Section titled âTechnical SpecificationsâThe following hard data points were extracted from the review, highlighting key performance metrics and material parameters for optimized Cu/Dia composites:
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Maximum Thermal Conductivity (TC) Achieved | 930 | W/(m K) | Cu-xZr alloy/diamond composite (Metal Infiltration) |
| Maximum Interface Thermal Conductance ($h_{c}$) | 90.9 | MW/(m$^{2}$ K) | Cu-xB alloy/diamond composite (Metal Infiltration) |
| Diamond Intrinsic TC (Theoretical Max) | 2200 | W/(m K) | High-purity artificial diamond reinforcement |
| Target Composite CTE Range | 4 - 6 | ppm/K | Tailored to match semiconductor chip materials |
| Typical Diamond Particle Size | 30 - 300 | ”m | Synthetic Single Crystal Diamond (SCD) |
| Optimized Interface Layer Thickness | 37 - 2110 | nm | Carbide layers (e.g., TiC, B$_{4}$C) |
| Typical Consolidation Temperature | 900 - 1150 | °C | VHP/SPS methods |
| Critical Surface Roughness (Roughness $\delta$) | < 1 | nm | Required for optimal Thermal Boundary Conductance (TBC) |
Key Methodologies
Section titled âKey MethodologiesâThe research reviewed relies on precise control over diamond material properties and consolidation parameters to maximize interfacial thermal conductance.
- Diamond Material Selection: Utilization of high-purity, synthetic Single Crystal Diamond (SCD) particles (30 ”m to 300 ”m range) to ensure high intrinsic thermal conductivity (TC is inversely related to nitrogen content).
- Surface Modification/Coating: Pre-coating diamond particles with carbide-forming elements (Ti, Cr, W, Mo, B) via PVD or CVD to create a chemically active layer that bonds strongly with both the diamond and the copper matrix.
- Powder Preparation: Mixing coated diamond particles with elemental copper powder or copper alloys containing carbide-forming additives.
- High-Density Consolidation: Employing high-pressure, controlled-temperature techniques (VHP, SPS, or HTHP) to achieve high relative density and promote the formation of a dense, uniform carbide interface layer.
- Example VHP Parameters: 950 °C, 40 MPa, 20 min.
- Example HTHP Parameters: Up to 1500 °C, 5 GPa.
- Interface Characterization: Analyzing the microstructure (TEM/SEM) to confirm the morphology, thickness, and chemical composition of the interfacial carbide layer (e.g., TiC, B$_{4}$C).
- Thermal Property Measurement: Measuring bulk TC and calculating ITC ($h_{c}$) using models like the Differential Effective Medium (DEM) model, often validated by Time-Domain Thermo-Reflectance (TDTR) experiments on simulated sandwich structures (e.g., Cu/TiC/Diamond).
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & CapabilitiesâThe research confirms that the quality, purity, and surface preparation of the diamond material are paramount to achieving high-performance Cu/Dia composites. 6CCVD is uniquely positioned to supply the advanced MPCVD diamond materials and customization services required to replicate and extend this research.
Applicable Materials
Section titled âApplicable MaterialsâTo achieve the high intrinsic TC required for the reinforcement phase (up to 2200 W/(m K)), researchers need low-defect, high-purity diamond.
- Optical Grade SCD: 6CCVD supplies high-purity Single Crystal Diamond (SCD) wafers and plates, which serve as the ideal base material for simulating the high-quality synthetic diamond particles used in this research. Our SCD ensures minimal nitrogen content, maximizing intrinsic thermal performance.
- High-Purity PCD: For large-area or high-volume fraction composite studies, our Polycrystalline Diamond (PCD) plates, available up to 125 mm in diameter, offer excellent thermal properties and scalability.
- Boron-Doped Diamond (BDD): We offer BDD materials, which can be used to study the effect of boron alloying (cited as achieving $h_{c}$ up to 90.9 MW/(m$^{2}$ K)) directly at the interface or within the matrix.
Customization Potential
Section titled âCustomization PotentialâThe paper emphasizes the critical role of the interfacial layer, requiring precise control over coating materials and surface morphology.
| Research Requirement | 6CCVD Customization Capability |
|---|---|
| Carbide-Forming Metalization (Ti, W, Cr, Cu layers) | In-House Metalization: 6CCVD provides internal deposition services for key carbide-forming elements, including Ti, W, and Cu, directly onto diamond substrates or wafers. This allows researchers to precisely control the thickness (down to 0.1 ”m) and uniformity of the interfacial layer for TDTR testing (e.g., Cu/TiC/Diamond structures). |
| Interface Roughness Control (Critical for TBC) | Precision Polishing: We guarantee ultra-low surface roughness: Ra < 1 nm for SCD and Ra < 5 nm for inch-size PCD. This capability is essential for minimizing phonon scattering and maximizing Thermal Boundary Conductance (TBC), a key factor discussed in the paper. |
| Custom Dimensions for Testing (Simulated interfaces, bulk samples) | Custom Dimensions and Thicknesses: We supply custom plates/wafers up to 125 mm (PCD) and precise thicknesses for SCD and PCD ranging from 0.1 ”m to 500 ”m, facilitating the fabrication of standardized samples for thermal testing methods like TDTR and 3Ï. |
| Near-Net Shape Prototyping (Future outlook) | Laser Cutting and Shaping: 6CCVD offers advanced laser cutting services to produce complex geometries and near-net shapes, supporting the industryâs need for cost-effective, practical thermal management products. |
Engineering Support
Section titled âEngineering SupportâThe complexity of optimizing ITC, which involves balancing phonon transmission, atomic intermixing, and bonding strength, requires deep material science expertise.
6CCVDâs in-house PhD engineering team specializes in MPCVD diamond growth, defect control, and surface functionalization. We can assist researchers and engineers with material selection, interface design, and optimization strategies for similar Copper/Diamond Composite Thermal Management projects, ensuring the diamond material meets the stringent purity and surface requirements necessary for high ITC.
Call to Action: For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
Abstract Copper/diamond composites have drawn lots of attention in the last few decades, due to its potential high thermal conductivity and promising applications in high-power electronic devices. However, the bottlenecks for their practical application are high manufacturing/machining cost and uncontrollable thermal performance affected by the interface characteristics, and the interface thermal conductance mechanisms are still unclear. In this paper, we reviewed the recent research works carried out on this topic, and this primarily includes (1) evaluating the commonly acknowledged principles for acquiring high thermal conductivity of copper/diamond composites that are produced by different processing methods; (2) addressing the factors that influence the thermal conductivity of copper/diamond composites; and (3) elaborating the interface thermal conductance problem to increase the understanding of thermal transferring mechanisms in the boundary area and provide necessary guidance for future designing the composite interface structure. The links between the compositeâs interface thermal conductance and thermal conductivity, which are built quantitatively via the developed models, were also reviewed in the last part.