Damage-free highly efficient plasma-assisted polishing of a 20-mm square large mosaic single crystal diamond substrate

Abstract

Plasma-assisted polishing (PAP) as a damage-free and highly efficient polishing technique has been widely applied to difficult-to-machine wide-gap semiconductor materials such as 4H-SiC (0001) and GaN (0001). In this study, a 20-mm square large mosaic single crystal diamond (SCD) substrate synthesized by microwave plasma chemical vapor deposition (CVD) was polished by PAP. Argon-based plasma containing oxygen was used in PAP to modify the surface of quartz glass polishing plate, and a high material removal rate (MRR) of 13.3 μm/h was obtained. The flatness of SCD polished by PAP measured by an interferometer was 0.5 μm. The surface roughness measured by both scanning white light interferometer (SWLI) (84-μm square) and atomic force microscope (AFM) (5-μm square) was less than 0.5 nm Sq. The micro-Raman spectroscopy measurement results of mosaic SCD substrate processed by PAP showed that residual stress and non-diamond components on the surface after PAP processing were below the detection limit.

Energy beam-based direct and assisted polishing techniques for diamond: A review

“…Even for the same crystal plane, there are harder or softer polishing directions. For example, the <100> direction, along which a higher removal rate and better surface quality can be obtained, is considered to be a soft direction on the (001) plane, Energy beam polishing techniques of diamond [8,39,46,48,[50][51][52][53]. Reproduced from [8] with permission from the Royal Society of Chemistry.…”

“…Liu and Yamamura et al [46,123] used an oxygen-argonbased plasma containing water vapor to modify the surface of a quartz glass polishing plate and achieved a high MRR of 13.3 µm h −1 when polishing SCD (100) substrate. As shown in figure 8(i), the surface roughness Sq after PAP is 0.458 nm, and the maximum surface height Sz is 8.884 nm.…”

“…With the rapid industrial revolution, diamond grinding and polishing technologies have continuously advanced, and many innovative diamond polishing techniques have been established. Mechanical polishing (MP) [30,31], chemical-mechanical polishing (CMP) [32,33], thermochemical polishing (TCP) [34,35], dynamic friction polishing (DFP) [36,37], laser polishing (LP) [38,39], ion beam polishing (IBP) [7,40], electrical discharge machining (EDM) [41,42], ultrasonic-assisted polishing (UAP) [43,44], plasma-assisted polishing (PAP) [45,46], and laser-assisted polishing (LAP) [47,48] are some of the commonly used techniques, each with its own advantages and limitations. Among them, MP has simple equipment and low processing costs, DFP has high polishing efficiency, and CMP and TCP have high polishing accuracy.…”

“…This method not only obtains high-quality surface but also provides high polishing efficiency. PAP has been applied to superhard materials such as diamond, sapphire, and silicon carbide [44,46]. LAP, which is based on laserinduced chemical reactions, has been successfully applied for the polishing of SCD, polycrystalline diamond (PCD), and CVD diamond films [47].…”

Atomic-level flatness on oxygen-free copper surface in lapping and chemical mechanical polishing

“…[5][6][7] The special working conditions of OFC components require it to have low damage, high dimensional accuracy and high surface atness. At present, the polishing methods used to obtain low damage and high surface accuracy include electrochemical polishing, 8 plasma-assisted chemical polishing, 9 bowl-feed polishing, 10 and chemical mechanical polishing. 11 All of the above methods can reduce the surface roughness and improve the machined surface quality, but some of them still have inevitable disadvantages.…”