Abstract: With the increasingly widespread high-end applications of silicon carbide (SiC) materials, high-quality machining of micro-scale geometric structures is urgently needed. However, limited research has been conducted on this topic so far. In this study, comparative micromilling experiments are performed on blind slot geometries in SiC materials using three types of tools: a self-developed polycrystalline diamond (PCD) micromilling cutter, a commercially available PCD micromilling cutter, and a commercially available PCD-coated micromilling cutter, with the aim of providing a reference for further research on SiC micromilling processes. Experimental results reveal that the commercial PCD-coated micromilling cutters suffered failure due to coating delamination and edge chipping, which precluded further analysis. It is demonstrated that the self-developed PCD micromilling cutters exhibited more stable cutting forces with lower values than commercial PCD micromilling cutters, as well as less bottom edge wear. Surface morphology analysis indicates that fully ductile-mode cutting was achieved by the self-developed tools, whereas mixed brittle-ductile material removal occurred in the case of commercial PCD micromilling cutters. The surface roughness (Sa) of slots machined by self-developed tools was measured as 4.931 μm, approximately half that of those machined by commercial PCD micromilling cutters. Through comparative analysis, it is confirmed that the self-developed PCD micromilling cutters demonstrate significant advantages in durability, machining stability, and surface quality for micromilling SiC blind slots, thus providing an effective tooling solution for advancing SiC micro-machining research.