Selective sealing and bonding of silicon-glass compounds and LIGA-components by laser beam welding

Laser beam welding is a useful tool in joining micromechanical systems and subdevices. In the past this technology has been used for a variety of applications, where metallic parts have to be joined. Depending on the available laser power, workpiece geometries from some 100 μm up to several millimeters have been processed in fully automatic manufacturing systems. With the strong market increase of microsystems and miniaturized sensor systems, the dimensions of the subcomponents as well as the whole part are steadily decreasing. With that decrease new materials like silicon and micro moulded polymer parts have to be investigated. For those materials suitable joining technologies must meet the demands of a microelectronics manufacturing with high accuracy, small interaction geometry, low temperature impact and short processing time. With this requirements laser beam welding of silicon glass compound and silicon polymer compounds has been developed. The technology is based on the different absorption behaviour of different material, where the laser beam is transmitted through the first joining partner and is absorbed by the second one. By heat conduction both partners are melted within a range of some micrometers and joining together. Examples of different joining geometries show the small and failure free joining zone, which can be designed with respect to the