SOLDER BONDING METHOD AND SOLDER JOINT

• Main Authors: KOSUGA, Tadashi, TAKEMASA, Tetsu, INABA, Ko
• Format: Patent
• Language: English; French; German
• Published: 25.12.2019
• Subjects: ALLOYS; BASIC ELECTRIC ELEMENTS; CASINGS OR CONSTRUCTIONAL DETAILS OF ELECTRIC APPARATUS; 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; ELECTRIC TECHNIQUES NOT OTHERWISE PROVIDED FOR; ELECTRICITY; FERROUS OR NON-FERROUS ALLOYS; MACHINE TOOLS; MANUFACTURE OF ASSEMBLAGES OF ELECTRICAL COMPONENTS; METAL-WORKING NOT OTHERWISE PROVIDED FOR; METALLURGY; PERFORMING OPERATIONS; PRINTED CIRCUITS; SEMICONDUCTOR DEVICES; SOLDERING OR UNSOLDERING; TRANSPORTING; TREATMENT OF ALLOYS OR NON-FERROUS METALS; WELDING; WORKING BY LASER BEAM

A solder bonding method for bonding an electrode of a circuit board and an electrode of an electronic component by forming a solder joint that exhibits excellent connection reliability while reducing thermal damage to the electronic component is provided. The solder bonding method is for bonding an electrode of a circuit board and an electrode of an electronic component by forming a solder joint and includes: forming, on the electrode of the circuit board, an Sn-Bi-based solder alloy having a lower melting point than a solder alloy formed on the electrode of the electronic component; mounting the electronic component on the circuit board such that the solder alloy formed on the electrode of the circuit board and the solder alloy formed on the electrode of the electronic component come into contact with each other; heating the circuit board to a peak temperature of heating of 150°C to 180°C with a holding time of the peak temperature of more than 60 seconds and 150 seconds or less; and cooling the circuit board at a cooling rate after the heating of 3°C/sec or more to form a solder joint.