Abstract: The invention relates to a lead-free solder foil for diffusion soldering and to the method for its production, with which method metallic structural parts and/or metallized/metal-coated structural parts, i.e. metallic surface layers of adjacent structural parts, may be bonded to one another. The task of the invention is to provide an economic and environmentally friendly lead-free solder foil that is not hazardous to health for diffusion soldering, with which the structural parts to be soldered can be bonded to one another in such a way, in a process temperature range typical of the soft soldering, i.e. at approximately 240° C. and in soldering times of shorter than 5 minutes, without a subsequent heat treatment and without the exertion of a pressing force during the soldering, that a continuous layer of a high-melting bonding zone is obtained in the form of an intermetallic phase having a remelting temperature of higher than 400° C.