Effects of processing parameters and grinding direction on the material removal mechanism of (100) surface single crystal diamond in self-rotating mechanical grinding

Abstract

The current commonly used method for diamond processing is mechanical polishing using the cast iron grinding wheel (Scaife). However, this method is challenging to meet the processing requirements of semiconductor applications. This study proposes a more efficient grinding method that employs a high-speed self-rotating grinding device, coupled with a bonded abrasive diamond grinding wheel with high self-sharpening properties, to achieve high precision grinding of single crystal diamonds. Different cutting depths, grit sizes, and linear velocities are employed in the processing, and the material removal mechanism is studied through morphology characterization, element content, and other detection methods. The experimental results indicate that the material removal method of diamond (100) crystal surface is influenced by the cutting depth. It is a collaborative removal process in the 〈110〉 and 〈100〉 directions, and the brittle-ductile transition in the <110> direction significantly affects the machining quality. Surface fractures and subsurface cracks primarily occur through cleavage along the (111) plane, so a method to distinguish the orientation of the (100) crystal plane is proposed. Additionally, this study demonstrates the influence of different processing directions on the surface of the diamond within the same plane. By using this method, the surface roughness of the 7 × 7 mm as-grown crystal can be reduced to Ra 0.523 nm within 10 min, with a material removal rate of 32.4 μm/h.