Laser based joining of monocrystalline silicon foils

Monocrystalline silicon is the basic material for many electronic applications such as solar cells or detectors. Joining of silicon foils is a very difficult task due to the brittleness of the monocrystalline silicon. It was shown that it is possible to join silicon substrates with thicknesses in the millimetre range by laser beam welding. To qualify the laser based joining under industrial environment a stable process has to be ensured. In this paper an analysis of the laser based joining process of silicon foils with a thickness of 50 μm is presented. The welding process is analyzed by finite element simulation and experimental studies. The simulation shows that at the end of the welding process a strong deformation of the foils appears. To validate the simulation model experimental investigations were carried out. The simulation and experimental results correspond very well in regard of the time dependent behaviour of the deformation. The deformation behaviour is attributed to the buckling mechanism.