Electrolytic copper plating, applications

In the present study, a novel surface treatment of microporous carbon, so-called electro copper plating which has been used in the application fields is provided to introduce copper onto activated carbons. And, the catalytic reduction mechanisms of NO over ACFs/Cu prepared by electrolytic copper plating have been studied. 

An alternative to the current methods is the use of a conducting polymer as an electrode for direct electrolytic metallization of copper. IBM demonstrated the use of polyaniline in this application [88]. Because of its solubility, the polymer can be directly deposited onto a PCB by a dip-coating process. In one study [88], a PCB was coated with a thick ( 1 /xm) layer of polyaniline applied from an aqueous acetic acid solution. Today, as a result of the many soluble polyaniline derivatives that have been developed, a variety of solvents including water can be used to apply the polymer. The polyaniline-coated board was electrolytically copper plated. As can be seen in Fig. 32.23b, the copper started to plate on the hole wall from the two contact sides and grew inward until the copper fronts met at the center of the hole wall. As the plating process continued, a thicker, uniform copper coating deposited on the polyaniline surface. 

Electroless nickel baths are usually preferred to electroless copper, since they tend to be more stable and are less likely to deposit metal on unwanted areas, such as plating racks. Electrolytic copper is then plated before the final application of nickel and chromium, where this is the required finish, as it... 

The process consists of pre-etching, etching, etch neutralization, catalyst application, catalyst activation, and plating. Most commercial applications, except RFI/EMI shielding, use the initial copper or nickel deposit as a base for subsequent electrolytic plating of electrolytic copper, nickel, or chromium. The exact types and thicknesses of metal used are determined by part usage, eg, automotive exterior, decorative, plumbing, and others (24). 

Copper was selected as the metallizing material because of its wide industrial application. Copper was then plated onto the preplate layer either by electroless or electroplating. A commercial solution was used for the electroless copper plating to obtain a 1.0-pm thick copper deposit. A 20 pm-thick layer of copper was deposited electrolytically under the following conditions. 

The correlation between the electrochemical transients observed on planar electrodes and superconformal film growth in sub-micrometer features indicates that the electrochemical metrics can be used for rapid screening of potential superfilling electrolytes. A more detailed and focused discussion of measurements and modeling of the SPS-PEG-C1 additive system for copper plating follows with the notion that the approach used is directly applicable to many other systems. 

One of the earliest applications to give acceptable analytical results appeared in a 1917 contribution by G. G. Grower, published in the ASTM Proceedings ( 5). Grower described a direct method for the determination of the thickness of a layer of tin plated on copper wire, through measurement of the quantity of electricity necessary to remove it electrolytically. A similar application was reported in 1938 by Cambell and Thomas ( ), and in 1939 by Zakhar evskii ),... 

Methane sulfonic acid is used as an electrolyte for electroplating of tin onto sheet steel, for plating tin and tin/lead alloy onto nickel or other base metal substrates in the manufacture of lead frames and bump-contacts for microelectronic devices.It can also be used for copper deposition during the manufacture of microprocessors. Other alkanesulfonic acids have also found use in electroplating applications. Disodium methanedisulfonate and other alkanedisulfonate salts are used in chrome plating.As discussed previously, several processes for the recovery and recycle of alkanesulfonic acids from spent metal plating baths have been described. 

For the electrochemical plating of silver, a 99.9% silver anode is used with an electrolyte composed of [Ag(CN)2] and other required additives. Silver should not come into direct contact with steel or severe corrosion can occur. Steel parts can be protected by first coating with copper or nickel. Silver coating is commonly used for flatware, hol-loware, jewelry, electrical, and mechanical applications. Chemical methods are available to apply silver as a coating to plastic or glass. 

Figure 26.4 shows a partial cut-away view of a fiber nickel-cadmium (FNC) cell. The case and cover are polypropylene and are welded together. The electrode assembly shows a negative electrode, a corrugated separator and a positive electrode. O-ring seals are employed in the bushings for the terminals to ensure gas retention and a vent valve is seen in the case cover between the terminals. A catalytic gas recombination plug in the vent valve is employed for some applications. The terminals are nickel-plated copper, and a 1.19 kg/L KOH electrolyte is typic ly employed. 

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