Abstract: The invention relates to a silver solder paste and to a silver solder paste containing copper, which can be used to join metal or metalized substrates, in particular copper substrates, without pressure at low temperatures. The silver solder according to the invention contains a metal-organic silver complex as a precursor, which forms silver nanoparticles only upon being heated and which forms a silver-metal molten phase over a temperature range of 20 to 40 units upon being heated further, which silver-metal molten phase can be used as a process window for joining already starting at 150° C., preferably starting at approximately 200° C.