The use of insoluble anodes in horizontal conveyorized printed circuit board manufacture: their effect on the performance and electrochemistry of acid copper electroplating solutions

The use of insoluble anodes has become critical to the viability of horizontal electroplating equipment. Despite this there have been few reported studies on the impact of using such anodes on the electrochemistry of acid copper plating solutions. A literature search therefore reviewed the different types of insoluble anode that had been previously utilized in sulphuric acid-based electrolytes and from this a number of criteria were established that might be applied when selecting an insoluble anode for horizontal acid copper electroplating. A 'life study' was then carried out to compare two electroplating baths, one operating with standard copper anodes, and the other insoluble anodes. [Continues.

Mechanism for the development of Sn-Cu alloy coatings produced by pulsed current electrodeposition

Pulsed current (PC) electrodeposition has become an essential tool for producing coatings in a wide range of industries. The pulsed current can have a significant influence on the composition, morphology and properties of electrodeposited coatings and this is particularly true when plating an alloy. In this study, the mechanism for the development of Sn-Cu alloy coatings produced by PC electrodeposition was investigated. Sn-Cu alloy coatings produced by PC electrodeposition were essentially composed of a dual layer of Sn-Cu electrodeposits and Cu6Sn5 inter metallic compounds (IMCs). In addition, it was observed that pulsed Sn-Cu electrodeposits exhibited an increased Cu content. Experiments were carefully designed to elucidate the mechanism for this important finding and based on their results a theory is proposed which explains the increased Cu content in terms of a metal displacement reaction occurring during the ‘relaxation’ time of PC electrodeposition.This file contains the preprint submitted for publication to Materials Letters. Published version of the manuscript can be found on Elsevier's ScienceDirect site https://www.sciencedirect.com/science/article/pii/S0167577X18301034?via%3Dihu