Building of super high-efficiency processing technology based on innovative concept (Establishment of effective polishing process of SiC substrate using Dilatancy pad tool with bowl feed method)

In this study, we propose innovative polishing method for hard-to-process semiconductor substrate such as SiC. Our innovative polishing method mainly consists of 2 technologies. One is unprecedented polishing pad “Dilatancy pad” composed of special filler and viscoelastic material. The other is high speed/pressure processing technology with bowl feed method. We aim at high efficiency and high grade polishing of hard-to-process substrate by the fusion of these 2 technologies. In a SiC polishing, Dilatancy pad can realize removal rates more than 3 - 6 times in comparison with a conventional metal plate or nonwoven fabric pad. At the same time, the occurrence frequency of the processing damage (scratches, outbreak depth of polishing damaged layers) can be improved drastically in comparison with conventional method. It means that using Dilatancy pad in the middle processing of the substrate can lighten the load from the final polishing by reducing generation of polishing damage compare to conventional process. In our proposed high speed/pressure processing with bowl feed method, stable polishing performance can be achieved even though huge pressure such as 1000 kPa is applied. Where, much higher removal rate is obtained compare to conventional low speed/pressure processing. Using both technologies for SiC polishing, removal rate of 9.3 μm/hr and surface roughness Ra of less than 3nm are achieved. From these result, we have figured out to shorten the total processing time of substrate, middle processing and final processing, by our innovative polishing method.