Wet Etching

In this treatment method laser radiation, which is guided from a coaxially expanding liquid jet-stream, locally initiates a thermochemical etching reaction on a metal surface, which leads to selective material removal at high resolution and quality of the treated surface as well as low thermal influence on the workpiece. Electrochemical investigations were performed under focused laser irradiation using a cw-Nd:YAG laser with a maximum power of 15 W and a simultaneous impact of the liquid jet-stream consisting of phosphoric acid with a maximum flow rate of 20 m/s. The time resolved measurements of the electrical potential difference against an electrochemical reference electrode were correlated with the specific processing parameters and corresponding etch rates to identify processing conditions for temporally stable and enhanced chemical etching reactions. Applications of laser-induced liquid-phase jet-chemical etching in the field of sensor technology, micromechanics and micrmoulding technology are presented. This includes the microstructuring of thin film systems, cutting of foils of shape memory alloys or the generation of structures with defined shape in bulk material.

In this work we present a locally developed MEMS-based technology for the assembly and characterization of optical MEMS components. For the assembly purpose, the processes required for the Si and glass micromachining (oxidation, photolithography and wet etching) are developed in the Laser lab at the faculty of Engineering, Ain Shams University. For the characterization purpose, an automated set-up for the

Recent research results are presented where lasers of different pulse durations and wavelengths have been coupled to near-field-scanning optical microscopes (NSOMs) through apertured bent cantilever fiber probes and atomic force microscope (AFM) tips in apertureless configurations. Experiments have been conducted on the surface modification of metals and semiconductor materials. By combining nanoscale ablative material removal with subsequent chemical etching steps,