| 摘要 |
PROBLEM TO BE SOLVED: To obtain a flat pulverized gradient functional copper alloy powder excellent in screen printing property as well as in reliability by specifying the concentration of silver at the surface and the distribution of silver concentration and also specifying the average thickness and grain size distribution of pulverized copper alloy powder, respectively, in a pulverized copper alloy powder containing specific amounts of silver. SOLUTION: As to pulverized copper alloy powder grain represented by general formula Agx Cuy [0.001<=x<=0.4, 0.6<=y<=0.999, and x+y=1 (atomic ratio) are satisfied], silver concentration is regulated so that the silver concentration at the surface of the grain is higher than the average silver concentration of the grain and also a region where silver concentration is increased with the approach from the inner part toward the surface exists in the vicinity of the surface. Moreover, the average thickness (ta) of the pulverized copper alloy powder grains is regulated to <=2μm, and the pulverized copper alloy of 0.01-0.5μm grain thickness (t) is regulated so that it comprises >=10% by number of the whole pulverized copper alloy. By this method, the flat pulverized gradient functional copper alloy powder excellent in electric conductivity and oxidation resistance and having superior electromigration resistance can be obtained.
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