Preform solder and method of manufacturing the same, and method of manufacturing solder joint
Provided is a preform solder including a first metal containing Sn and a second metal formed of an alloy containing Ni and Fe. Alternatively, provided is a preform solder ( 1 ) having a metal structure including a first phase ( 10 ) that is a continuous phase and a second phase ( 20 ) dispersed in the first phase ( 10 ), the first phase ( 10 ) contains Sn, the second phase ( 20 ) is formed of an alloy containing Ni and Fe, and a grain boundary ( 15 ) of a metal is present in the first phase ( 10 ).
1. A preform solder comprising a first metal containing Sn, and a second metal formed of an alloy containing Ni and Fe,
wherein a melting point of the first metal is 250° C. or less,
a melting point of the alloy in the second metal exceeds 250° C.,
a content of Sn in the first metal is 100 mass % or less with respect to a total mass of the first metal,
a content of Ni in the second metal is 80 mass % or more and 99 mass % or less with respect to a total mass of the second metal,
a content of Fe in the second metal is 1 mass % or more and 20 mass % or less with respect to the total mass of the second metal,
a particle size of the second metal is 0.1 to 1000 μm,
a content of the second metal is 5 to 70 mass % with respect to a total content of the first metal and the second metal, and
when the preform solder is mounted on a Cu board having a thickness of 0.5 mm and a size of 50 mm ×50 mm, an Si board having a thickness of 0.4 mm and a size of 5 mm ×5 mm is mounted on the preform solder, soldering is performed, and then, in a profile in which a peak temperature is 250° C. and a cooling speed is 2° C./sec, the soldering is performed in a reflow furnace with no pressurization or with pressurization under formic acid atmosphere to fabricate a solder joint, the solder joint has a shear strength of 1.0 N or more in a bonding area, the shear strength being measured under a condition of 6.0 mm/min and 250° C.
2. A preform solder having a metal structure comprising a first phase that is a continuous phase, and a second phase dispersed in the first phase,
wherein the first phase is formed of a metal containing Sn,
the second phase is composed of an alloy containing Ni and Fe,
a melting point of the metal that composes the first phase is 250° C. or less,
a melting point of the alloy that composes the second phase exceeds 250° C.,
a content of Sn in the metal that composes the first phase is 20 mass % or more and 100 mass % or less with respect to a total mass of the metal,
a content of Ni in the alloy that composes the second phase is 80 mass % or more and 99 mass % or less with respect to a total mass of the alloy,
a content of Fe in the alloy that composes the second phase is 1 mass % or more and 20 mass % or less with respect to the total mass of the alloy,
a particle size of the alloy is 0.1 to 1000 μm,
the content of the alloy that composes the second phase is 5 to 70 mass % with respect to a total content of the metal that composes the first phase and the alloy that composes the second phase, and
a grain boundary of the metal is present in the first phase.
3. The preform solder according to claim 2 , wherein a content of an intermetallic compound of Sn and Ni in the metal structure is 0 mass % or more and 70 mass % or less with respect to a total mass of the metal structure.