Study on the mechanism and machining characteristics of single-crystal silicon cutting by micro-discharge abrasive cutting

Abstract

In response to the current challenges of low cutting efficiency and poor surface quality in processing single-crystal silicon, this article proposes the utilization of the micro-discharge abrasive cutting (MDAC) method for processing single-crystal silicon. A comprehensive comparison is conducted among the processing characteristics of the new cutting method and fixed abrasive wire sawing (FAWS) and wire electrical discharge machining (WEDM), including cutting efficiency, surface morphology, subsurface damage, surface roughness, wire saw wear, elemental spectrum analysis, and kerf width. Besides, two material removal modes at different feed rates are discussed. The results indicate that compared with WEDM, MDAC has the advantages of minimal subsurface damage, low surface roughness, low residual elements, and small kerf width. MDAC has higher cutting efficiency and shallower scratch depth than FAWS. However, compared with WEDM and FAWS, MDAC results in more significant wire saw wear and leaves a small amount of residual nickel on the silicon surface. In MDAC, the discharge occurs first. When the discharge energy within the pulse width is sufficient to remove the material within the current pulse cycle, the material is completely removed by the discharge action, the discharge products remain on the surface of the silicon wafer. When the discharge energy is insufficient to remove the material within the current pulse cycle, the silicon ingot is removed under the combined action of discharge and grinding, the diamond on wire saw surface will remove most of the discharge products.

Keywords

• Micro-discharge
• Mechanism
• Processing characteristics
• Single-crystal silicon
• Surface morphology