Flux, solder paste, and electronic circuit board
A flux used for soldering with a tin-silver-copper alloy comprises an imidazole compound and/or an imidazoline compound; a dicarboxylic acid having 3 or more and 36 or less carbons; and a quaternary ammonium iodine salt. Relative to the total amount of the flux, the dicarboxylic acid content is 6 mass % or more and 25 mass % or less, and the iodine content is 200 ppm or more and 3600 ppm or less.
1. A flux used for soldering with a tin-silver-copper alloy, the flux comprising:
an imidazole compound and/or an imidazoline compound;
a dicarboxylic acid having 3 or more and 36 or less carbons; and
a quaternary ammonium iodine salt;
wherein relative to the total amount of the flux;
the dicarboxylic acid content is 6 mass % or more and 25 mass % or less, and
an iodine content is 200 ppm or more and 3600 ppm or less.
2. The flux according to claim 1 , wherein the imidazole compound includes an imidazole compound having 2 or more aromatic rings.
3. The flux according to claim 1 , wherein the imidazoline compound includes an imidazoline compound having 1 or more aromatic ring(s).
4. The flux according to claim 1 , wherein, relative to the total amount of the flux, the iodine content is 200 ppm or more and 2600 ppm or less.
5. The flux according to claim 1 , wherein, relative to the total amount of the flux, the iodine content is 600 ppm or more and 1230 ppm or less.
6. The flux according to claim 1 , wherein the dicarboxylic acid includes a dicarboxylic acid having 3 or more and 25 or less carbons and a dicarboxylic acid having 30 or more and 36 or less carbons, and
relative to a total amount of the dicarboxylic acids, a ratio of the dicarboxylic acid having 30 or more and 36 or less carbons exceeds 50 mass %.
7. The flux according to claim 1 , wherein the dicarboxylic acid includes a dicarboxylic acid having 10 or more and 25 or less carbons and a dicarboxylic acid having 30 or more and 36 or less carbons, and
relative to a total amount of the dicarboxylic acids, a ratio of the dicarboxylic acid having 30 or more and 36 or less carbons exceeds 50 mass %.
8. A solder paste comprising:
the flux according to claim 1 ; and
a solder powder made of an tin-silver-copper solder alloy, wherein
the tin-silver-copper solder alloy contains bismuth and antimony,
relative to a total amount of the tin-silver-copper solder alloy,
the bismuth content is 2.5 mass % or more, and
the antimony content is 2.5 mass % or more.
9. The solder paste according to claim 8 , wherein the tin-silver-copper solder alloy consists of tin, silver, copper, bismuth, antimony, nickel, cobalt, and inevitable impurities, wherein:
relative to a total amount of the tin-silver-copper solder alloy,
the silver content is 2.8 mass % or more and 4 mass % or less,
the copper content is 0.4 mass % or more and 0.8 mass % or less,
the antimony content is 2.5 mass % or more and 7 mass % or less,
the bismuth content is 2.5 mass % or more and 5.5 mass % or less,
the nickel content is 0.01 mass % or more and 0.2 mass % or less, and
the cobalt content is 0.001 mass % or more and 0.1 mass % or less.
10. An electronic circuit board comprising a solder portion soldered with the solder paste according to claim 8 .