Diamond/copper composite material, ultra-high thermal conductivity semiconductor packaging substrate

With the development of microelectronics technology, the characteristics of high-density assembly and miniaturization are becoming more and more obvious. The heat flux density of components is increasing, and the requirements for new substrate materials are becoming higher, requiring higher thermal conductivity, better matching thermal expansion coefficient, and better stability. Diamond, as a new generation substrate material, is receiving more and more attention. Diamond/metal matrix composite materials, as substrate materials for electronic packaging, have been preliminarily verified to have both low thermal expansion coefficient and high thermal conductivity, and have been applied on a small scale.

In addition, with the surge in the application of generative AI models such as ChatGPT, a new demand for heat dissipation has emerged. The heat dissipation of high-performance chips has always been a prominent challenge in the service of electronic products, especially in the "post Moore era", where the power and heat flux density of advanced packaged multi chip systems increase sharply. The heat flux density of chip hotspots can even reach the level of nuclear bomb explosions in kW/cm2, which is also the key to limiting the power consumption, computing power, and integration of high-performance chips.

The requirements for packaging substrate materials include high electrical resistivity, high thermal conductivity, low dielectric constant, dielectric loss, good thermal compatibility with silicon and gallium arsenide, high surface smoothness, good mechanical properties, and ease of industrial production.

The thermal conductivity of SiC ceramics is high, and the higher the purity of SiC crystals, the greater the thermal conductivity; The biggest drawback of SiC is its high dielectric constant and low dielectric strength, which limits its high-frequency applications and is only suitable for low-density packaging. AlN material has excellent dielectric properties and stable chemical properties, especially its thermal expansion coefficient that matches silicon, making it a promising semiconductor packaging substrate material. However, the current highest thermal conductivity is only 260W/(m · K). With the increasing demand for heat dissipation in semiconductor packaging, AlN material also faces certain development bottlenecks. Therefore, developing substrate materials with high thermal conductivity and more complete performance has become a trend, and diamond is gradually entering the market.

Diamond is currently known to have the highest thermal conductivity in nature. The thermal conductivity of single crystal diamond is 2200-2600 W/(m.K), with a thermal expansion coefficient of about 1.1 × 10-6/℃. It has many excellent properties in semiconductor, optics, and other fields. Although a single diamond is not easy to make into packaging materials and has a high cost, it is superior to other ceramic substrate materials in terms of thermal conductivity by tens or even hundreds of times.

Diamond is a substrate material with high thermal conductivity and excellent heat dissipation. It has broad application prospects in high temperature environments and is the best semiconductor material for manufacturing low-power, high-power density devices.CSMH focuses on the production and research and development of diamond materials. Its core products include diamond heat sinks, diamond optical windows, diamond wafers, diamond heterojunction integrated composite substrates, AlN thin films, etc. Currently, it has applications in high-power LEDs, lasers, 5G communication, aerospace, new energy vehicles, GPUs, and other fields.