Material processing—An overview

Laser researchers in the early 1960´s found that a ruby laser could easily melt and vaporize small amounts of metal. Many investigations have since been performed to determine the effects of high-power laser radiation on absorbing surfaces. By the late 1960´s lasers had become practical production tools. In the early 1970´s, advances in the power of CO2lasers led to deep penetration laser welding. This greatly increased the range of metal thickness amenable to laser processing. At present, lasers are used in a practical way for many applications in material processing. For some applications, like trimming of resistors and drilling of holes in ceramics, laser processing is the leading method. For other applications like heat treating, welding, and cutting, laser processing is an economically competitive alternative to conventional techniques. In addition, there are new research possibilities, especially for processing of semiconductors. Areas such as laser-assisted crystal regrowth and annealing of ion-implantation damage point toward new methods of generating semiconductor circuitry. This paper will review the physical phenomena which underlie laser processing applications. It will also give an overview of some of the leading uses for laser-based material processing.