Electro-Optics Handbook, Second Edition
Developed by a towering figure in the field, this valuable, all-inclusive guide thoroughly explains and discusses the use of optical devices and light in electronics systems.
TABLE OF CONTENTS Electro-Optics Handbook, Second Edition
Chapter 25: MATERIAL PROCESSING APPLICATIONS OF LASERS
James T. Luxon
In this chapter we deal with the types of lasers used in material processing applications and the characteristics of these lasers which are pertinent to the applications. Appropriate optical materials and devices will he described. The general advantages and disadvantages of lasers in materials processing are discussed. Brief discussions of the major processing applications are presented. The applications of lasers in microelectronic manufacturing are too numerous to discuss in detail; hence a brief overview is presented.
25.1 MATERIAL PROCESSING LASERS
This discussion will be limited to three types of lasers, all of which have been discussed to some extent in previous chapters. These are the neodymium-doped yttrium aluminumgarnet (Nd:YAG) laser, the CO 2 laser, and the excimer laser.
Nd:YAG Lasers
The Nd:YAG laser is a solid-state laser which emits radiation at a wavelength of 1.06 m. Power levels are available from a few watts to over 1000 W average power. Applications are typically hole piercing, cutting, welding, and marking. Nearly all these applications are to metals. Absorption by metals at this wavelength is fairly high. Polymeric materials and glass are too transparent unless coated or an absorptive filler material is present.
In most applications, this laser is pulsed to increase peak power and to decrease thermal damage to the workpiece. In marking applications, Q switching is used to create rapidly repeating short pulses with peak powers that reach 1200 times the average power. For cutting, drilling, and welding applications, the laser is electronically pulsed. Pulse shaping is...
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