Laser microfabrication: present to future applications

Abstract

Product miniaturisation and component intricacies require advanced processing technologies to satisfy functionality and quality requirements. Various micro-machining technologies have been under extensive development so as to be able to fill this niche. In particular, the development of MEMS devices utilises machining methods that include silicon fabrication and LIGA technologies. Lasers present an alternative or supplementary tool for micro-fabrication. Present advances in laser system design are bringing about great improvements in beam quality, increase in high peak power, increase in high pulse energy, and shorten pulse width. This enables direct machining of a wide variety of materials with feature sizes down to the order of micrometers.This paper presents some of the recent developments in utilising laser to micro-machine or microfabricate micro-features on devices. Many of these processes are being used in production, or are expected to be commercially feasible.

Laser micromachining of the materials using in microfluidics by high precision pulsed near and mid-ultraviolet Nd:YAG lasers

“…Those physical properties would cause the photothermal process to dominate in the laser micromachining using both the 266 nm and 355 nm lasers. The result of the pulse-energy normalized ablation rates indicates 266 nm laser provides higher laser ablation efficiency for both photothermal and photochemical processes due to the higher absorption coefficient and higher photon energy for the 266 nm laser (Mai and Nguyen, 2002;Baeuerle, 2000;Lim and Mai, 2002;Craciun and Craciun, 1999;Hermanns, 2000).…”

Fundamentals of Laser Ablation of the Materials Used in Microfluiducs

“…This implies that a predominantly thermal process was engaged in the laser micromachining of Pyrex by the 266 nm and 355 nm lasers. However, Pyrex shows better ablation efficiency using 266 nm laser due to more photochemical process at the higher absorption coefficient and higher energy (Mai & Nguyen, 2002;Baeuerle, 2000;Lim & Mai, 2002;Craciun & Craciun, 1999;Craciun et al, 2002;Hermanns, 2000).…”

Parametric studies on pulsed near ultraviolet frequency tripled Nd:YAG laser micromachining of sapphire and silicon

“…The laser machining process on silicon exhibits more of a photothermal process for the relatively high laser ablation rate and a poorer surface finish by using the near UV pulsed Nd:YAG laser. The cratered morphology generated by the laser ablation of silicon indicated laser-induced boiling, especially, at the laser machining conditions of lower scan speeds and higher laser fluence [1,3,11,12].…”