US 12,392,015 B2
Printed wiring board, printed circuit board, and electronic component
Hisao Ishikawa, Tochigi (JP); Masao Kayaba, Saitama (JP); and Akira Ogihara, Kanagawa (JP)
Assigned to ISHIKAWA TECHNOLOGY LABORATORY CO., LTD., Tochigi (JP); KAYABA OFFICE CO., LTD., Saitama (JP); and Akira Ogihara, Kanagawa (JP)
Filed by ISHIKAWA TECHNOLOGY LABORATORY CO., LTD., Tochigi (JP); KAYABA OFFICE CO., LTD., Saitama (JP); and Akira Ogihara, Kanagawa (JP)
Filed on Sep. 18, 2023, as Appl. No. 18/469,534.
Application 18/469,534 is a division of application No. 17/496,756, filed on Oct. 7, 2021, granted, now 11,802,322.
Application 17/496,756 is a continuation of application No. PCT/JP2020/015963, filed on Apr. 9, 2020.
Claims priority of application No. 2019-074215 (JP), filed on Apr. 9, 2019; application No. 2020-043538 (JP), filed on Mar. 12, 2020; application No. 2020-069965 (JP), filed on Apr. 8, 2020; and application No. 2020-069966 (JP), filed on Apr. 8, 2020.
Prior Publication US 2024/0002979 A1, Jan. 4, 2024
Int. Cl. B23K 35/26 (2006.01); B23K 101/42 (2006.01); C22C 1/02 (2006.01); C22C 13/00 (2006.01); H05K 1/18 (2006.01); H05K 3/34 (2006.01)
CPC C22C 1/02 (2013.01) [B23K 35/262 (2013.01); C22C 13/00 (2013.01); H05K 1/181 (2013.01); H05K 3/3463 (2013.01); B23K 2101/42 (2018.08)] 3 Claims
OG exemplary drawing
 
1. A printed wiring board comprising:
a substrate;
a wiring pattern layer formed in a thin-film shape on the substrate, the wiring pattern layer constituting a wiring pattern; and
a solder layer formed in a thin-film shape on the wiring pattern layer, the solder layer containing a solder, wherein
the solder in the solder layer is manufactured by a method comprising:
a heating step of heating and melting a raw material to obtain a molten metal, the raw material containing tin as a main component, a metal element other than lead as a secondary component, and a carboxylic acid having 10 to 20 carbons;
a removing step of removing, from the molten metal set to a pre-filtration temperature from 230° C. to 260° C., solids having a diameter of more than 10 μm and present within the molten metal by filtering the solids with a filter having an aperture size of not more than 10 μm, wherein the filter is heated by a heater, and a post-filtration temperature of the filtered molten metal is 230° C. to 260° C.; and
a cooling step of cooling and solidifying the molten metal with the solids removed therefrom and depositing the carboxylic acid at a surface of the solder product to form a surface layer.