Laser cleaning technology for micro and nano device applications

In micro and nano device fabrication technology, local material removal is one of the basic operations for structure formation. This technology involves different materials in form of thin films. The materials of the greatest interest are: photo resist and different metals (aluminum, gold, copper, titanium). Classical methods for structure formation on the surface of a silicon wafer are based mainly on chemical processing, starting with photo etching, chemical etching, and chemical-mechanical linearization. In order to propose new methods of higher quality from the point of view of environment protection and also from the point of view of the processing quality we have studied the possibility of thin films controlled removal under the action of laser radiation. As a laser source we have used an excimer laser, with the wavelength of 248 nm and pulse duration 30 ns. Materials tested in our experiments for laser removal were: photoresist, thickness 0.2-12 μm; metals (gold, aluminum, copper and titanium). Substrate material was silicon wafer with a mirror quality surface.