Study on subsurface microcrack damage depth of diamond wire as-sawn sapphire crystal wafers

Abstract

Sapphire crystals are widely used as window materials for infrared emitting devices, high intensity lasers, optical elements and microelectronic substrates due to the excellent material properties. The subsurface microcrack damage produced by diamond wire saw when cutting sapphire crystal is an important indicator of the cutting quality. In this paper, diamond wire sawing experiments were conducted within the industrial production processing parameters to investigate the as-sawn sapphire crystal wafers subsurface microcrack damage depth (SSD), and a numerical calculation model was established to predict the SSD based on the analysis of the scratching stress field of single abrasive. The effects of the saw wire speed and specimen feed speed, saw wire parameters on SSD were predicted. The results show that, within the parameters studied in this paper, the material was removed in brittle mode, increasing the saw wire speed (from 1000 m/min to 1600 m/min) and reducing the specimen feed speed (from 0.5 mm/min to 0.05 mm/min) can reduce the sapphire as-sawn wafers SSD, reduce the size of brittle tear-shape edge breakage, the number and size of brittle pits on the as-sawn wafer surface are reduced and the surface morphology consistency is improved. Increasing the abrasive density and reducing the abrasive size can reduce the SSD. The study results provide a reference for the reasonable matching of sawing process parameters and saw wire parameters in industry.