| Borosilicate glass is widely used in optical communications, optoelectronics as well as biomedical technologies and microelectromechanical systems (MEMS). However, it is very difficult to machine this material by conventional machining techniques because of its inherent brittleness. Laser micromachining is an alternative approach for machining of glass. Further, UV transparent materials, such as quartz, and sapphire are materials of importance in optical and optoelectronics because of their outstanding properties, such as transparency in a wide wavelength range and strong damage resistance for laser irradiation. However, laser micromachining of these dielectrics is restricted due to their high transparency. Laser induced backside wet etching (LIBWE) is a novel one step technique for machining transparent materials, such as quartz, fused silica, and sapphire. Excimer lasers possess short pulse lengths, high average as well as peak powers. This lends excimer laser as an appropriate tool for micromachining applications. In this investigation, micromachining of borosilicate glass and quartz is conducted using a short pulse (FWHM = 25 ns) KrF Excimer Laser (248 nm wavelength) that generates laser energy in the range of 100--600 mJ. The machined surfaces were examined using conventional optical and laser interference microscopes. The impact of changing major operating parameters, such as pulse fluence and different media on the resulting micromachining geometries is studied. Simple as well as complex geometries, such as microfluidic channels, inductors, part geometries used in medical applications, and RF circuits were machined. |
