There are three grade diamond wafer, Microelectronics Grade Diamond Wafer for wafer fabrication, Thermal Grade Diamand Wafers and Slices and Optical grade diamond wafers:
1.Microelectronics Grade Diamond Wafer for wafer fabrication
1.1 specification of Microelectronics Grade Diamond Wafer
|Diamond Wafer||Polycrystalline Diamond|
|Wafer Size||1cm*1cm;2inch; custom|
|Surface Roughness||Ra< 1 nm|
|Coefficient of Thermal Expansion||1.3×10^-6 K^-1|
|Thermal conductivity||>1000 W/m.K|
1.2 Manufacturing flow of Microelectronics Grade Diamond Wafer
1.3 XRD spectra of 2inch CVD diamond Wafer.
The primary crystal facets orientation of CVD diamond films is (111) plane.
1.4 Raman spectra of 2inch CVD diamond Wafer.
There is only one single diamondpeak at 1333.48 cm-1.
1.5 SEM micrographs( × 1k) of the 2-inch diamond Wafer after roughpolishing .
1.6 AFM micrographs of the 2-inch diamond wafer after rough polishing.
Image Ra = 137 nm with the scanning area of 5×5 μm2.
1.7 SEM micrographs(× 1k) of the 2-inch diamond wafer after finishing polishing.
1.8 AFM micrographs of the 2-inch diamond wafer after finishing polishing.
Image Ra = 0.278 nm with the scanning area of5×5 μm2.
Image Ra = 0.466 nm with the scanning area of 15×15 μm2.
1.9 EDS results for polished films.
The content of elements on the polished area is all carbon. No metal contaminationfrom the polishing plate.
1.10 XPS results for polished films.
2.Thermal Grade Diamand Wafers and Slices
Diamond exhibits the highest thermal conductivity among all materials. Its thermal conductivity is up to 2000 W/mK which is higher a lot than that of copper. Therefore diamond wafers and slices become more and more popular in thermal management as heatspreaders,heatsinks, lithographically patterned metallization, electrical isolation between top and bottom metallization, stress relieving slits for stress free mounting etc.
CVD diamond heat spreaders in various shapes,and the typical parameters are as follows:
|Diameter||80mm, or small size such as 5*5mm2|
|Process||DC Arc Plasma|
|Chemical composition||100% C|
|Young’s modulus||1000-1100 Gpa|
|Thermal conductivity||C>1,000 W/m.K, B>1300W/m.K,A>1800W/m.K|
|Tensile strength||>350 kg/mm²|
|Vickers Hardness||7000~10000 kg/mm²|
|Wear resistance(abrasion ratio)||100,000~200,000|
|Chemical Stability||Insoluble in alkali and acid|
|Surface finish polished||＜50 nm|
|Surface finish lapped||＜0.5 um|
3.Optical grade diamond wafers
Optical grade diamond wafers are used as window for infrared beam splitters, lenses for terahertz spectroscopy and CO2 laser surgery,Brewster Windows for multi-spectral applications such as free electron lasers, multi-wavelength IR lasers or terahertz optical systems,for Units attenuated total reflection) spectroscopy,for diamond Liquid Cells.