2018 Volume 62 Issue 3 Pages 148-153
The production volume of light-emitting diodes (LEDs), which are energy-saving products, is increasing to achieve low-carbon societies. Therefore, it is necessary to improve the productivity of sapphire wafers as substrates for LEDs. To improve the removal rate of chemical mechanical polishing (CMP) of sapphire substrate, we developed a high-efficiency method using ultrasonic vibration as mechanically assisted CMP and clarified its mechanism of action. This study confirmed the cavitation phenomenon in the vicinity of the substrate induced by ultrasonic vibration, and examined the effects of this phenomenon on the removal rate. Furthermore, the effects of ultrasonic vibration were verified using two types of suede-type polishing pad with different characteristics. The results indicated that in conventional CMP, the removal rate is increased by using a suede-type polishing pad with a large number of pores. In ultrasonic vibration-assisted CMP, the removal rate can be improved depending on the characteristics of the suede-type polishing pad.
