Patent ID: 8444779

Claim:
A copper allot for electronic material, containing 1.0 to 2.5 mass % of Ni, 0.5 to 2.5 mass % of Co, and 0.30 to 1.2 mass % of Si, wherein one or more of the following conditions (a)-(d) are optionally satisfied: (a) Cr is furthermore contained in a maximum amount of 0.5 mass %; (b) a single element or two or more elements selected from Mg, Mn, Ag, and P are furthermore contained in total in a maximum amount of 0:5 mass %; (c) one or two elements selected from Sn and Zn are furthermore contained in total in a maximum amount of 2.0 mass %; and (d) a single element or two or more elements selected from As, Sb, Be, B, Ti, Zr, Al, and Fe are furthermore contained in total in a maximum amount of 2.0, mass %, the balance being Cu and unavoidable impurities; wherein the copper alloy satisfies the following conditions in relation to the compositional variation and the surface area ratio of second-phase particles size of 0.1 μm or greater and 1 μm or less when observed in ten arbitrary locations each having an observation field of 30 μm×30 μm in a cross section parallel to a rolling direction: the median value ρ(mass %) of a [Ni+Co+Si] content satisfies the formula 20 (mass %)≦ρ≦54 (mass %) based on the mass of said second phase particles, the standard deviation σ(Ni+Co+Si) satisfies the formula 13≦σ(Ni+Co+Si)≦28 (mass %) based on the mass of said second phase particles, and: the surface area ratio S (%) satisfies the formula 2.0%≦S≦7.1%.