The Interface and Fabrication Process of Diamond/Cu Composites with Nanocoated Diamond for Heat Sink Applications

Abstract

The coefficients of thermal expansion (CTE) and thermal conductivity (TC) are important for heat sink applications, as they can minimize stress between heat sink substrates and chips and prevent failure from thermal accumulation in electronics. We investigated the interface behavior and manufacturing of diamond/Cu composites and found that they have much lower TCs than copper due to their low densities. Most defects, such as cavities, form around diamond particles, substantially decreasing the high TC of diamond reinforcements. However, the measurement results for the Cu-coated diamond/Cu composites are unsatisfactory because the nanosized copper layer on the diamond surface grew and spheroidized at elevated sintering temperatures. Realizing ideal interfacial bonding between a copper matrix and diamond particles is difficult. The TC of the 40 vol.% Ti-coated diamond/Cu composite is 475.01 W m−1 K−1, much higher than that of diamond/Cu and Cu-coated diamond/Cu composites under equivalent manufacturing conditions. The minimally grown titanium layer retained its nanosized and was consistent with the sintering temperature. Depositing a nanosized titanium layer on a diamond surface will strengthen interfacial bonding through interface reactions among the copper matrix, nanosized titanium layer and diamond particles, reducing the interfacial thermal resistance and exploiting the high TC of diamond particles, even if defects from powder metallurgy remain. These results provide an important experimental and theoretical basis for manufacturing diamond/Cu composites for heat sink applications.

Enhancement Effect of a Diamond Network on the Flow Boiling Heat Transfer Characteristics of a Diamond/Cu Heat Sink

“…Molian-Jordá [33,34] utilized the DEM model to simulate the thermal conductivity of bimodal diamond, and the simulated values closely matched the experimental values. Given that their CLTE closely matches that of semiconductor materials, diamond/Cu composites can theoretically be applied in the field of heat transfer for semiconductor chip packaging [35]. Heat sinks fabricated by utilizing the high thermal conductivity of diamond/Cu composites also exhibit excellent thermal dissipation performance near the chip.…”

Strengthening Mechanisms and Retention Properties of Sintered Iron-Based Matrix Material for Metallic-Diamond Tools

“…Zhang et al [21] evaluated the effect of W-coated diamond fraction on the microstructure and thermal conductivity of the composites. Li et al [22] investigated the interface and fabrication process of Ti-nanocoated and Cunanocoated diamond composites. The nanosized Cu and Ti layers were deposited on the diamond particles in a vacuum ion plating process.…”

Archives of Metallurgy and Materials

“…in order to maintain high hardness and wear resistance, bonds of grinding tools are normally based on ferrous and non-ferrous alloys such as Fe, Cu, Co, ni, Zn, and Sn. The typical bonding matrix for this group of tools includes various compositions based on either Cu, Co, or Fe [7]. The addition of Co and Fe ensures excellent tool life but deteriorates grinding performance.…”