Diamond wafer: The Key material for achieving efficient heat dissipation of packaging substrates

With the increase of chip power, heat dissipation issues are becoming increasingly prominent. Traditional packaging techniques are no longer able to meet these requirements. Heat sink materials with high thermal conductivity, such as diamond, will be more widely used.

General packaging substrates include Al2O3 ceramics, SiC ceramics, AlN materials, etc.

However, the thermal expansion coefficient (7.2 × 10-6/℃) and dielectric constant (9.7) of Al2O3 are relatively high compared to Si single crystals, and the thermal conductivity (15-35W/(m · K)) is still not high enough, resulting in Al2O3 ceramic substrates not being suitable for use in high-frequency, high-power, and ultra large scale integrated circuits;

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.

Diamond is currently known to have the highest thermal conductivity in nature. Single crystal diamond has a thermal conductivity of 2200-2600 W/(m.K), polycrystalline diamond has a thermal conductivity of 1000-2200 W/(m.K), and a thermal expansion coefficient of about 1.1 × 10-6/℃. It has many excellent properties in semiconductors, optics, and other fields, with a high cost, but it is superior to other ceramic substrate materials in terms of thermal conductivity by tens or even hundreds of times, It will be an excellent choice for chip packaging substrates!

CSMH is committed to the research of diamond and other heat sink materials, mastering internationally leading diamond thermal management products and solutions. It currently has core products such as diamond wafers, diamond heat sinks, diamond windows, and diamond heterojunction integrated composite substrates. Among them, the surface roughness of diamond wafer Ra<1nm; The thermal conductivity of diamond heat sink is 1000-2200W/m.k, and the technical indicators have reached the world's leading level. Diamond heat sink has been applied in many fields such as high-power electronic devices, 5G base stations, new energy vehicles, aerospace, etc.