LEAD FREE HIGH TEMPERATURE CONNECTION

A simple method is provided for firmly-bonded connection of an electronic component to a substrate, which dispenses with the use of lead-containing paste solders and leads to a contact layer featuring sufficiently high resistance to heat fatigue in an environment characterized by incessant periodical temperature variations, and featuring high thermal and electrical conductivity. The method for firmly-bonded connection of an electronic component to a substrate includes the steps of: (a) providing an electronic component having a first surface to be connected and a substrate having a second surface to be connected; (b) applying a paste solder to at least one of the surfaces to be connected; (c) arranging the electronic component and the substrate such that the first electronic component surface to be connected and the second substrate surface to be connected contact each other through the paste solder; and (d) soldering the arrangement from (c) in order to generate a firmly-bonded connection between the electronic component and the substrate, wherein the paste solder contains (i) 10-30% by weight copper particles, (ii) 60-80% by weight particles of at least one substance selected from the group consisting of tin and tin-copper alloys, and (iii) 3-30% by weight solder flux, wherein the mean particle diameter of the particles (i) and of the particles (ii) is no more than 15 μm, and wherein the thickness of the applied layer of paste solder is at least 20 μm.