A method of batch soldering, comprising: forming a first soldered joint between a metal region of a first semiconductor die and a first metal region of a substrate using a first solder preform via a soldering process which does not apply pressure directly to the first semiconductor die, the first solder preform having a maximum thickness of 30 μm and a lower melting point than both the metal region of the first semiconductor die and the first metal region of the substrate; setting a soldering temperature of the soldering process so that the first solder preform melts and fully reacts with the metal region of the first semiconductor die and the first metal region of the substrate to form one or more intermetallic phases throughout the entire first soldered joint, each of the one or more intermetallic phases having a melting point above the melting point of the preform and the soldering temperature; and being characterised by the following steps: soldering a second semiconductor die (200") to the first or different metal region (208, 208', 208") of the substrate, without applying pressure directly to the second semiconductor die (200"), wherein soldering the second semiconductor die (200") to the substrate comprises: forming a second soldered joint between a metal region (208") of the second semiconductor die (200") and the first or different metal region (208, 208', 208") of the substrate using a second solder preform (204") or a soft solder paste, via the same soldering process used to form the first soldered joint and without applying pressure directly to the second semiconductor die (200"), wherein if the second soldered joint is formed using a second solder preform (204"), the second solder preform (204") is thicker than the first solder preform, and the second soldered joint is devoid of intermetallic phases in a middle part of the second soldered joint. forming a first soldered joint between a metal region of a first semiconductor die and a first metal region of a substrate using a first solder preform via a soldering process which does not apply pressure directly to the first semiconductor die, the first solder preform having a maximum thickness of 30 μm and a lower melting point than both the metal region of the first semiconductor die and the first metal region of the substrate; setting a soldering temperature of the soldering process so that the first solder preform melts and fully reacts with the metal region of the first semiconductor die and the first metal region of the substrate to form one or more intermetallic phases throughout the entire first soldered joint, each of the one or more intermetallic phases having a melting point above the melting point of the preform and the soldering temperature; and being characterised by the following steps: soldering a second semiconductor die (200") to the first or different metal region (208, 208', 208") of the substrate, without applying pressure directly to the second semiconductor die (200"), wherein soldering the second semiconductor die (200") to the substrate comprises: forming a second soldered joint between a metal region (208") of the second semiconductor die (200") and the first or different metal region (208, 208', 208") of the substrate using a second solder preform (204") or a soft solder paste, via the same soldering process used to form the first soldered joint and without applying pressure directly to the second semiconductor die (200"), wherein if the second soldered joint is formed using a second solder preform (204"), the second solder preform (204") is thicker than the first solder preform, and the second soldered joint is devoid of intermetallic phases in a middle part of the second soldered joint. forming a second soldered joint between a metal region (208") of the second semiconductor die (200") and the first or different metal region (208, 208', 208") of the substrate using a second solder preform (204") or a soft solder paste, via the same soldering process used to form the first soldered joint and without applying pressure directly to the second semiconductor die (200"), wherein if the second soldered joint is formed using a second solder preform (204"), the second solder preform (204") is thicker than the first solder preform, and the second soldered joint is devoid of intermetallic phases in a middle part of the second soldered joint.