Characterization of Sapphire Lapping Process using Various Metal-resin Platens with Diamond Slurry

Abstract

LED (Light-Emitting Diode) is recognized as one of the most effective energy-saving optical device. Sapphire single crystal is one of the popular candidates used as a substrate material for opto-electronics such as LED, because of its unique properties like high-temperature stability, chemical resistance and high hardness. The lapping process is necessary to control the flatness and thickness before GaN deposition because it’s influence to the performance of LED device. However, during a sapphire lapping process is difficult to get a high removal rate and achieve good surface quality due to its mechanical properties. Therefore, high sapphire removal rate and surface quality is required for the device performance. In this study, the performance of a sapphire lapping process using a new composite metal platen (metal-resin platen: Cu-resin, Al-resin and Tin-resin) was evaluated with an oil based diamond slurry. The sapphire material removal rate (MRR) was increased linearly with the increase a rotation speed, down load force and diamond abrasive size. The lapping time also affected the sapphire removal rate and the surface quality. Finally, we got that copper-resin platen with a diamond slurry could achieve a good surface quality and the higher removal rate of sapphire. The sapphire removal mechanism was discussed based on the experimental result.