Patent ID: 11993862

Abstract:
A structure includes a copper or copper alloy plating layer, in which Kirkendall void formation is suppressed. The copper or copper alloy plating layer is formed by electroplating at a prescribed first cathode current density by using a copper or copper alloy electroplating bath and then completing the electroplating after the first cathode current density is changed to a lower second cathode current density. The first cathode current density is a single cathode current density in the electroplating at this current density or an average cathode current density in the electroplating by combining plural cathode current densities. The first cathode current density is at lowest 5 A/dm2. A layer formed by changing the first cathode current density to the second cathode current density is a surface layer part of the copper or copper alloy plating layer, which can have a thickness of 0.05 μm to 15 μm.