Nihon Micro Coating Co., Ltd.

Naoyuki Hamada

Kenji Aoki

Toru Yamazaki

Takabumi Marukawa

Takehiro Watanabe

Kanichi Endo

A hard crystal substrate such as a GaN substrate or a SiC substrate is polished by using polishing oil slurry having abrading particles of artificial diamond clusters dispersed in a dispersant. The artificial diamond clusters include approximately spherical agglomerate particles with average particle size D50 of 20 nm or more and 50 nm or less, having primary particles with particle diameters of 2 nm or more and 10 nm or less. A rough polishing process is carried out first such that an average surface roughness of 0.5 nm or more and 1 nm or less is obtained, followed by a finishing process such that the average surface roughness of said surface becomes 0.2 nm or less.

Method of polishing hard crystal substrate

A mirror-finishing method embodying this invention, with which the above and other objects can be accomplished, may be characterized as comprising the step of supplying a solution containing hydroxyl groups on a target surface to be polished of a glass substrate while simultaneously pressing onto this target surface an elastic sponge material having abrading particles affixed therein and a plurality of indentations on a polishing surface thereof, and causing the substrate and the sponge material to move with respect to each other.

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Tokyo, Japan

Naoyuki Hamada