Study on surface characteristics of as-sawn sapphire crystal wafer considering diamond saw wire wear

Abstract

Sapphire crystal is widely used as Light Emitting Diode (LED) substrate and window materials for electronic devices. During the sawing process of sapphire crystal, the wear of saw wire leads to different sawing performance. In this paper, the abrasives wear state, the diameter change and wear rate of the saw wire, the change of surface morphology and surface roughness (SR) of as-sawn sapphire crystal wafer during the whole service cycle of saw wire under typical sawing parameters were analyzed, and the stable service period of diamond saw wire was determined. Further, sawing experiments were conducted during the stable service period of diamond saw wire, and the effects of sawing parameters within the industrial production on the as-sawn sapphire crystal wafers surface characteristics were studied. The results show that within range of sawing parameters adopted in this paper, the abrasives mainly remove the material in a brittle mode, and the SR of the as-sawn wafers decreases as the saw wire speed increases (from 1000 m/min to 1600 m/min), and the as-sawn wafer surface morphology is improved. As the specimen feed speed increases (from 0.05 mm/min to 0.5 mm/min), the SR increases, and the consistency of the as-sawn wafer surface morphology deteriorates.