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Electroplating of palladium‐nickel alloy is becoming widely used, mainly for interconnection applications in the electronics industry and for decorative purposes. Enhanced hardness and brightness combined with superior wear properties compared with hard gold deposits make this alloy desirable in many applications. Like pure palladium, palladium‐nickel is frequently covered with a thin layer of hard gold to improve contact reliability; this results in a much less expensive and longer‐lasting contact material than hard gold on its own. In response to the growing demand, the authors have developed a palladium‐nickel alloy electroplating process that can plate alloys of varying composition (10–50 w % Ni) at current densities ranging from <5 mA/cm to >500 mA/cm. This process produces specular, hard and ductile deposits up to a thickness of ‐25 ?m. The new palladium‐nickel alloy electroplating process is described with regard to its chemistry, operating conditions, bath maintenance and regeneration, diagnostic measures, and properties of the electrodeposits.

A novel tin electrodeposition chemistry and process has been developed at Bell Laboratories, Lucent Technologies, New Jersey, USA. This process produces smooth, satin bright tin deposits which have stable, large grain structures. The deposits contain very low organic content and, as a consequence, exhibit excellent ductility, solderability and reflowability. The chemistry is capable of operating at elevated temperatures over a wide range of current densities, and is, thus, applicable to rack, barrel and reel‐to‐reel operations. All chemical components, including breakdown products are fully analyzable with conventional analytical methods. Extensive bath life studies show that the deposit appearance and material properties, including grain structures, are stable in relation to the age of the electroplating chemistry. In addition, the grain refiners used are highly stable, and have few breakdown products as the chemistry ages. All these features imply a robust process which has been confirmed in various manufacturing environments. This tin electroplating process has been utilized in plating coatings for connectors, solder bumps, PWBs and components for semiconductor applications.

Multi‐layer surface finish, from the bottom to top, of electroless Ni, electroless Pd, and immersion Au (Ni/Pd/Au) have been introduced in the printed circuit board (PCB) industry recently. This paper reports an evaluation of this surface finish from the perspective of solder joint attachment reliability, especially to see if the Ni/Pd/Au could be immune from the brittle interfacial fracture of PBGA on electroless Ni/immersion Au, recently observed and reported by us. PCBs with Ni/Pd/Au finishes, made from two vendors with varied Pd layer thickness were attached with PBGA packages, and tested in four‐point bending. When joint strength is strong, bending tests resulted in peeling off the PCB pads; otherwise, brittle fractures occurred at the interface between solder balls and PCB pads. After aging, solder joints on all Ni/Pd/Au and reference metal finishes failed by the same brittle fracture at the interface between Ni‐Sn and Au‐Sn intermetallic compounds. It is concluded that the interfacial fracture was controlled by something other than the Pd, and the existence of the Pd did not prevent the interfacial fracture. Also, the presence of Pd could not prevent the Au migration and subsequent fracture.

Protection techniques for zinc. Similar to aluminium, zinc produces in air an oxidised surface layer which acts as corrosion protection.