Abstract: The Cu core ball contains a Cu ball and a solder layer for covering a surface of the Cu ball. The Cu ball contains at least one element selected from Fe, Ag, and Ni in a total amount of 5.0 or more to 50.0 ppm by mass or lower, S in an amount of 0 or more to 1.0 ppm by mass or lower, P in an amount of 0 or more to less than 3.0 ppm by mass, and remainder of Cu and inevitable impurities. The Cu ball contains purity which is 99.995% or higher and 99.9995% by mass or lower, and sphericity which is 0.95 or higher. The solder layer includes Ag in an amount of more than 0 to 4.0% by mass or less, Cu in an amount of more than 0 to 3.0% by mass or less, and remainder of Sn.

Abstract: The present invention provides a solder material containing Sn or a Sn-containing alloy and 40 to 320 ppm by mass of A, the solder material including an As-enriched layer.

Abstract: The Cu core ball contains a Cu ball and one or more metal layer for covering a surface of the Cu ball, each layer including one or more element selected from Ni, Co, Fe and Pd. The Cu ball contains at least one element selected from Fe, Ag, and Ni in a total amount of 5.0 or more to 50.0 ppm by mass or lower, S in an amount of 0 ppm by mass or more to 1.0 ppm by mass or lower, P in an amount of 0 ppm by mass or more to less than 3.0 ppm by mass, and remainder of Cu and inevitable impurities. The Cu ball contains purity which is 99.995% by mass or higher and 99.9995% or lower, sphericity which is 0.95 or higher and a diameter of 1 ?m or more to 1000 ?m or lower.

Abstract: Provided is a flux containing not less than 11.0 degrees and not more than 17.0 of a contact angle between the flux and a resist substrate on which the flux has been printed to have 1.0 mm of a diameter and 0.15 mm of a thickness when heating the resist substrate at 150 degrees C. for 30 seconds and cooling the resist substrate to a room temperature. The flux also contains more than zero seconds and not more than 2.0 seconds of a zero-cross time when heating a Cu plate at 150 degrees C. in a thermostat oven for 12 hours, applying the flux onto the baked Cu plate, and dipping the baked Cu plate onto which the flux is applied into a Sn-3.0Ag-0.5Cu alloy at a dipping speed of 15 mm/sec and by 2.0 mm of a dipped depth.

Abstract: The Cu core ball contains a Cu ball and a solder layer for covering a surface of the Cu ball. The Cu ball contains at least one element selected from Fe, Ag, and Ni in a total amount of 5.0 or more to 50.0 ppm by mass or lower, S in an amount of 0 or more to 1.0 ppm by mass or lower, P in an amount of 0 or more to less than 3.0 ppm by mass, and remainder of Cu and inevitable impurities. The Cu ball contains purity which is 99.995% or higher and 99.9995% by mass or lower, and sphericity which is 0.95 or higher. The solder layer includes Ag in an amount of more than 0 to 4.0% by mass or less, Cu in an amount of more than 0 to 3.0% by mass or less, and remainder of Sn.

Abstract: The Cu core ball contains a Cu ball and one or more metal layer for covering a surface of the Cu ball, each layer including one or more element selected from Ni, Co, Fe and Pd. The Cu ball contains at least one element selected from Fe, Ag, and Ni in a total amount of 5.0 or more to 50.0 ppm by mass or lower, S in an amount of 0 ppm by mass or more to 1.0 ppm by mass or lower, P in an amount of 0 ppm by mass or more to less than 3.0 ppm by mass, and remainder of Cu and inevitable impurities. The Cu ball contains purity which is 99.995% by mass or higher and 99.9995% or lower, sphericity which is 0.95 or higher and a diameter of 1 ?m or more to 1000 ?m or lower.

Abstract: A Cu core ball contains a Cu ball and at least one metal layer for covering a surface of the Cu ball. The metal layer is made of at least one element selected from the group of Ni, Co, Fe and Pd. The Cu ball contains at least one element selected from a group of Fe, Ag and Ni in a total amount of 5.0 ppm by mass or more to 50.0 ppm by mass or lower, S in an amount of 0 ppm by mass or more to 1.0 ppm by mass or lower, P in an amount of 0 ppm by mass or more to less than 3.0 ppm by mass, and remainder of Cu and inevitable impurities. The Cu ball contains purity which is 99.995% by mass or higher to 99.9995% by mass or lower, and sphericity which is 0.95 or higher.

Abstract: Provided is a flux containing not less than 11.0 degrees and not more than 17.0 of a contact angle between the flux and a resist substrate on which the flux has been printed to have 1.0 mm of a diameter and 0.15 mm of a thickness when heating the resist substrate at 150 degrees C. for 30 seconds and cooling the resist substrate to a room temperature. The flux also contains more than zero seconds and not more than 2.0 seconds of a zero-cross time when heating a Cu plate at 150 degrees C. in a thermostat oven for 12 hours, applying the flux onto the baked Cu plate, and dipping the baked Cu plate onto which the flux is applied into a Sn-3.0Ag-0.5Cu alloy at a dipping speed of 15 mm/sec and by 2.0 mm of a dipped depth.