Internal Modification Technique of Sapphire by Picosecond Pulsed Fiber Laser

Abstract

It is important to reduce the edge damage in cleavage of sapphire substrate for cost reduction. In this study, the internal modification technique of a sapphire substrate by picosecond pulsed fiber laser were investigated. Internal modification of sapphire with a high aspect ratio such as 5µm width and 150µm height were successfully performed by the irradiation from the epitaxial layer side. A sapphire wafer of 0.4 mm thickness could be broken from the internal modified line without less damage of the epitaxial layer.