Basic Investigation on Nd:YAG-laser beam joining of silicon for opto-electronic components
- Prof. Dr.-Ing. Dr.h.c. M. Geiger
- Prof. Dr. rer. nat. A. Winnacker, Universität Erlangen
Many optic and opto-electronic components are based on silicon as substrate or chip material. Laser assisted joining techniques in addition to conventional joining methods are relevant for new products as well as for the improvement of well known components. What is the potential of laser joining concerning silicon substrates and optical fibers?
With the help of FE-simulations and experimental investigation on pulsed laser processing, a process model describes phase transformations and the resulting new geometry (bump). Based on this knowledge, laser assisted joining of optical fibers in silicon-V-grooves, especially welding and soldering are described. The laser soldering might be able to supplement or even to replace the well known gluing. Because of its material behavior, silicon is not suited for welding. Laser welding of silicon substrates causes cracks in the weld and in the heat affected zone. Numerical and experimental work shows, that a global or local preheating reduces tensile stress. Using suitable laser and process parameters, crack free laser welding is possible.