METHOD FOR JOINING WHOLE OF JUNCTION FACE OF ELEMENT TO SUBSTRATE BY USING Au-Sn ALLOY SOLDER PASTE

• Main Authors: OBINATA MASAYOSHI, ISHIKAWA MASAYUKI, MISHIMA TERUSHI
• Format: Patent
• Language: English
• Published: 17.01.2008
• Subjects: ALLOYS; BASIC ELECTRIC ELEMENTS; CHEMISTRY; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; ELECTRIC SOLID STATE DEVICES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; FERROUS OR NON-FERROUS ALLOYS; MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR; METALLURGY; PERFORMING OPERATIONS; SEMICONDUCTOR DEVICES; SOLDERING OR UNSOLDERING; TRANSPORTING; TREATMENT OF ALLOYS OR NON-FERROUS METALS; WELDING; WORKING BY LASER BEAM

PROBLEM TO BE SOLVED: To provide a method for joining an element such as an LED (light-emitting diode) element to a substrate by using, particularly an Au-Sn alloy solder paste. SOLUTION: The junction face of the element 1 is turned upward so as to mount or apply the Au-Sn alloy solder paste 6 on it. The Au-Sn alloy solder paste 6 is melted by applying reflow processing to it in a non-oxidizing atmosphere while leaving the element in the state of being mounted or applied with the Au-Sn alloy solder paste. A molten Au-Sn alloy solder layer is formed over the whole surface of the junction face of the element 1, and also, it is cooled and solidified so as to form a solidified Au-Sn alloy solder layer 7. The element 1 having the solidified Au-Sn alloy solder layer 7 is reversed so that the element 1 is placed on the substrate 4 in order to make the solidified Au-Sn alloy solder layer 7 in contact with the substrate 4. The element is subjected to reflow processing in the non-oxidizing atmosphere in that state so as to join the element 1 to the substrate 4 via an Au-Sn alloy solder junction part 9 without voids. COPYRIGHT: (C)2008,JPO&INPIT