Proposal of Magnetic-Force-Assisted Polishing Method

Abstract

To reduce the size of the polisher, especially the polishing head, a novel method for applying the polishing load using magnetic force is proposed. As the fabrication of next-generation power device substrates advances, such as diamond, ultra-precise planarization via chemical mechanical polishing (CMP) becomes crucial for transforming these substrates into functional devices. Achieving CMP necessitates the application of an optimal polishing load to the substrate. Deadweight and air pressure methods are the traditional mechanisms for delivering this load. However, they tend to increase the size and complexity of the polishing head mechanism, hindering its miniaturization. This study proposes leveraging the magnetic force for the application of polishing load. Such an approach not only promises the miniaturization of the polishing head but also paves the way for smaller polishers. We constructed a prototype polisher with a straightforward mechanism and conducted several tests. The removal rate measurements from these tests, when compared with those of the traditional deadweight method in prior research, validated our approach. Additionally, by adjusting the magnet spacing (which adjusts magnetic force) and the rotational speed, we found that the removal rate adheres to Preston’s law even when employing the magnetic force for polishing.