Effects of a quartz beam-guide on high-precision laser-assisted etching ofAl2O3 ceramics

Laser-assisted chemical etching of ceramic materials has been attracting co ntinuous attention as a laser microfabrication technique with relatively lo w power levels. In this study, in order to improve the accuracy of etching depth and diameter, the application of a quartz beam-guide to the pulsed Nd :YAG laser-assisted etching process is proposed. By using this technique, p ossibilities of high-precision hole drilling with high aspect ratio and uni form surface etching in the radial direction of the beam using a beam-homog enizing effect of the beam-guide have been investigated for Al2O3 ceramics immersed in H3PO4 solution at room temperature. The results revealed that: (1) the distance between the beam-guide surface and the workpiece surface d ominates the surface etching rate; (2) by using the beam-guide, the beam-ho mogenizing effect in the radial direction of the beam at the surface is con firmed; and (3) possibilities of uniform surface etching and high-precision hole drilling are demonstrated by applying the beam-homogenizing effects o f the beam-guide. (C) 1999 Elsevier Science S.A. All rights reserved.