Lasers in the manufacturing of LEDs

Abstract

Lasers are becoming increasingly important in today's LED revolution and are essential for increasing the efficiency and reducing manufacturing cost of LEDs. Excimer lasers provide unique homogeneous illumination of large areas, and are ideally suited for laser lift off (LLO) of the LED film from the sapphire substrate used for epitaxial growth. In this paper we will discuss the excimer laser lift off technique for manufacturing vertical type LEDs, and how it can be applied to GaN and AlN based LEDs. On the other hand, diode pumped solid state lasers excel in scribing and cutting of a number of materials relevant to the LED industry: sapphire, silicon, silicon carbide, III-nitrides (gallium nitride and aluminum nitride), as well as III-V semiconductors (gallium arsenide, gallium phosphide). In this paper we will discuss some of the recent laser scribing techniques and how adequate selection of laser parameters and beam delivery optics allows for a high quality high throughput process.