Diamond wafers: the ideal choice for semiconductor packaging substrates

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, more matched thermal expansion coefficients, and better stability. And diamonds with these excellent characteristics have emerged.

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

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, which makes Al₂O₃ ceramic substrates unsuitable 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, with a thermal conductivity of 2200-2600 W/(m.K) and a thermal expansion coefficient of about 1.1 × 10^-6/℃. It has excellent properties in semiconductors, optics, and other fields that other packaging materials cannot achieve.

CSMH. is committed to the production and research of diamond heat sink materials, mastering professional and leading thermal management products and solutions, and can provide COS packaging, TO packaging, etc. CSMH has a mature product system, including diamond heat sinks, diamond windows, diamond wafers, diamond heterojunction integrated composite substrates, etc. The products have been applied in many fields such as high-power lasers, aerospace, radar, and new energy vehicles.