According to one embodiment, a wet-area device includes a main part, a first layer, and a second layer. The first layer is provided on an outer surface of the main part. The second layer is provided on an outer surface of the first layer. A hardness of the second layer is greater than a hardness of the first layer. The first layer includes a first unevenness at a side of the outer surface of the first layer. The first unevenness includes a plurality of recesses and a plurality of protrusions. The second layer includes a second unevenness at a side of an outer surface of the second layer. The second unevenness includes a plurality of recesses and a plurality of protrusions. The second unevenness is arranged along the first unevenness. An average height of the first unevenness is less than an average length of the first unevenness.

The present disclosure generally relates to the field of tin electroplating. More specifically, the present disclosure relates to methods for mitigating tin whisker formation on tin-plated films and tin-plated surfaces by doping the tin with germanium.

The present disclosure generally relates to the field of tin electroplating. More specifically, the present disclosure relates to methods for mitigating tin whisker formation on tin-plated films and tin-plated surfaces by doping the tin with germanium.

A PCB terminal is provided with a rod-like base material and a plating layer covering a predetermined region of the base material. A constituent material of the base material is a copper alloy containing 20% by mass or more of zinc. The plating layer includes a first coating portion and a second coating portion. The first coating portion includes an entire peripheral layer entirely covering a region on side of a first end part, out of both end parts of the base material, in a circumferential direction of the base material. The second coating portion partially covers a region on side of a second end part, out of the both end parts of the base material, in the circumferential direction of the base material. The entire peripheral layer includes a tin-based layer and a barrier layer.

A PCB terminal is provided with a rod-like base material and a plating layer covering a predetermined region of the base material. A constituent material of the base material is a copper alloy containing 20% by mass or more of zinc. The plating layer includes a first coating portion and a second coating portion. The first coating portion includes an entire peripheral layer entirely covering a region on side of a first end part, out of both end parts of the base material, in a circumferential direction of the base material. The second coating portion partially covers a region on side of a second end part, out of the both end parts of the base material, in the circumferential direction of the base material. The entire peripheral layer includes a tin-based layer and a barrier layer.

An anti-corrosion terminal material including a base material made of copper or copper alloy and a coating film laminated on the base material: the coating film includes: a first coating film, provided with a zinc layer made of zinc alloy and a tin layer made of tin or tin alloy which are laminated in this order, and formed at a planned core contact part; and a second coating film including the tin layer but not comprising the zinc layer, which is provided at a planned contact part being a contact part when the terminal is formed: and the zinc layer has a thickness not less than 0.1 μm and not more than 5.0 μm and zinc concentration not less than 30% by mass and not more than 95% by mass, and has any one or more of nickel, iron, manganese, molybdenum, cobalt, cadmium, lead and tin as a balance.

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/dm.sup.2. 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.

Provided is an electroplating solution of tin or a tin alloy in which the thickness variation of wafer bumps is maintained at a low level even in various changes of plating conditions and thus the mass productivity is improved. The electroplating solution of tin or a tin alloy may include tin ions as metal ions, a conductive salt, a carboxylic acid as a structure refiner, and a combination of a flavone compound and a quaternary ammonium compound as a thickness variation improving agent.

Provided is an electroplating solution of tin or a tin alloy in which the thickness variation of wafer bumps is maintained at a low level even in various changes of plating conditions and thus the mass productivity is improved. The electroplating solution of tin or a tin alloy may include tin ions as metal ions, a conductive salt, a carboxylic acid as a structure refiner, and a combination of a flavone compound and a quaternary ammonium compound as a thickness variation improving agent.

An electroplating bath for depositing a silver/tin alloy on a substrate. The electroplating bath comprises (a) a source of tin ions; (b) a source of silver ions; (c) an acid; (d) a first complexing agent; (e) a second complexing agent, wherein the second complexing agent is selected from the group consisting of allyl thioureas, aryl thioureas, and alkyl thioureas, and combinations thereof; and (f) optionally, a wetting agent, and (g) optionally, an antioxidant.