US 12,290,884 B1
Solder paste and solder joint
Shinji Kikuchi, Tokyo (JP); Yoshie Tachibana, Tokyo (JP); Tomoki Sasaki, Tokyo (JP); and Ayumi Mio, Tokyo (JP)
Assigned to SENJU METAL INDUSTRY CO., LTD., Tokyo (JP)
Filed by SENJU METAL INDUSTRY CO., LTD., Tokyo (JP)
Filed on Jan. 14, 2025, as Appl. No. 19/020,375.
Claims priority of application No. 2024-008280 (JP), filed on Jan. 23, 2024.
Int. Cl. B23K 35/30 (2006.01); B23K 35/02 (2006.01)
CPC B23K 35/3033 (2013.01) [B23K 35/025 (2013.01)] 3 Claims
OG exemplary drawing
 
1. A solder paste comprising:
a first metal powder;
a second metal powder; and
a flux,
wherein the first metal powder contains Sn,
the second metal powder has a core portion formed of an alloy containing Ni and Fe, and a surface layer that covers the core portion and is formed of a metal containing Ni,
an Sn content in the first metal powder is 20% by mass or more and 100% by mass or less relative to a total mass of the first metal powder,
an Ni content in a metal forming the core portion of the second metal powder is 80% by mass or more and 99% by mass or less relative to a total mass of the metal forming the core portion of the second metal powder,
an Fe content in the metal forming the core portion of the second metal powder is 1% by mass or more and 20% by mass or less relative to the total mass of the metal forming the core portion of the second metal powder,
an Ni content in the metal forming the surface layer of the second metal powder is 50% by mass or more relative to a total mass of the metal forming the surface layer of the second metal powder,
a particle diameter of the first metal powder is 0.1 to 1,000 μm,
a particle diameter of the second metal powder is 0.2 to 1,000 μm, and
the surface layer of the second metal powder has a thickness of 0.05 μm or more and 0.30 μm or less.