New Product | CSMH Unveils Ultra-Thin Diamond Film Technology, Pushing the Boundaries of Chip Thermal Management

Thermal management has become a critical limiting factor in semiconductor device performance as power densities continue to escalate. As conventional thermal management approaches reach their physical limits, CSMH has focused its research and development on ultra-high-thermal-conductivity diamond materials, building a comprehensive portfolio of technical solutions spanning the wafer level to the package level. CSMH has recently introduced ultra-thin silicon-on-diamond (SOD) wafer technology with diamond film thicknesses below 1 μm on 4-inch, 6-inch, and 8-inch substrates, while simultaneously advancing freestanding diamond film technology to thicknesses of 5−25 μm; well below the prevailing industry standard. These developments mark a significant step in expanding the application boundaries of diamond and unlocking new possibilities for chip-level thermal management.

Ultra-Thin Silicon-on-Diamond Films

Drawing on deep MPCVD process expertise, CSMH has achieved direct growth of polycrystalline diamond films below 1 μm in thickness on silicon substrates across 4-inch, 6-inch, and 8-inch wafer diameters, while retaining high thermal conductivity. Integrated at the wafer fabrication stage, the silicon-on-diamond film functions as a near-junction lateral heat spreader: heat generated at the active device region is immediately redistributed in-plane across the diamond layer, suppressing temperature rise at its source before it propagates through the device stack. The process is fully compatible with existing silicon wafer manufacturing specifications, including wafer bow, total thickness variation (TTV), and surface roughness requirements, enabling seamless adoption into RF and power device production lines without modification to existing infrastructure.

△ 6-inch silicon-on-diamond (SOD) wafer (diamond film thickness: 0.5 μm)

Ultra-Thin Freestanding Diamond Flexible Films

In the field of freestanding diamond films, CSMH has achieved another key breakthrough. The company has successfully fabricated self-supporting polycrystalline CVD diamond membranes with thicknesses below 25 μm, significantly thinner than the 50 μm industry baseline, while maintaining uniform thickness distribution, high thermal conductivity, and surface roughness values suitable for direct bonding and metallization. The films exhibit macroscopic mechanical flexibility, eliminating the need for adhesive carriers or rigid backing substrates, and support laser dicing for precise custom geometric definition. This combination of properties enables seamless integration with advanced back-end processes, including wafer-level packaging (WLP) and 3D chip stacking, establishing a practical package-level thermal management solution. Key application segments include thermal management for flexible devices, electrically insulating thermally conductive interlayers for high-frequency components, substrates for optoelectronic devices, and heat spreading in high-power chip assemblies.

From near-junction silicon-on-diamond heat spreading at the wafer level to flexible freestanding films at the package level, CSMH is redefining the boundaries of chip thermal management through diamond technology innovation. As thermal management transitions from passive heat conduction to an active enabler of device performance, CSMH will continue to advance its development of ultra-high thermal conductivity diamond materials, working with partners across the industry to deliver efficient, cost-competitive thermal solutions for high-performance computing, advanced packaging, photonic chips, power semiconductors, and flexible electronics.