Electrodeposition printed circuit boards

Manufacture of Printed Wiring Boards. Printed wiring boards, or printed circuit boards, are usually thin flat panels than contain one or multiple layers of thin copper patterns that interconnect the various electronic components (e.g. integrated circuit chips, connectors, resistors) that are attached to the boards. These panels are present in almost every consumer electronic product and automobile sold today. The various photopolymer products used to manufacture the printed wiring boards include film resists, electroless plating resists (23), liquid resists, electrodeposited resists (24), solder masks (25), laser exposed photoresists (26), flexible photoimageable permanent coatings (27) and polyimide interlayer insulator films (28). Another new use of photopolymer chemistry is the selective formation of conductive patterns in polymers (29). 

In industrial applications of metal deposition a metal M is deposited either on the native metal substrate M or on a foreign metal substrate S. As an example of the former, Cu is electrodeposited on a Cu substrate formed by electroless Cu deposition on an activated nonconductor in the fabrication of printed circuit boards. As an example of the latter, Ni is electrodeposited on Cu in the fabrication of contact pads in the electronics industry. 

The hard gold is used in electrical connectors, printed circuits boards, and mechanical arrays and it is produced by electrodeposition. The electrolytic methods (electrodeposition) are not discussed in this chapter. 

Electrodeposition of copper is one of the most important deposition processes in industry. Copper is already being refined by electrolysis. Copper plating is the main deposition process for the production of printed circuit boards. Plating processes for many applications are known with varying results for the characteristic properties of the deposits. Examples are... 

Printed circuit board (PCB) technology was employed for the fabrication of electrodes to be employed for luminol-H202 solutions. These electrodes were used with two microfluidic ECL cells that combine transparent polydimethylsiloxane (PDMS) microchannels [16]. The differences between the two cells were the working electrode size (10 mm Au vs 0.09 mm Au) and the ECL detection volume (4 pL vs 4 nL). No counter electrode was used in this system while Ag/AgCl reference electrode was obtained by electrodeposition of Ag on Au,... 

Murao, K. Fabrication of printed circuit boards provided with bhnd via-holes plugged with copper by electrodeposition. Jpn. Kokai Tokkyo Koho JP 2006009079, 2006 Chem. Abstr. 2006,144, 116371. 

The future of cathodic metal removal seems to be fruitful, since it is a mature technology, and there is a wide variety of cell designs commercially available nowadays. A promising field of application is recovery of precious metals from, e.g., spent catalysts and printed circuit boards, in which cell design and cell potential are usually not critical due to the value of the metal. Selective metal electrodeposition from a mixture of different ions is still a challenge, especially when the electrodeposition overpotentials are very close. 

Other electroless and electrolytic metal plating applications using CPs have been described in several patents [1006-1010]. For example, Sonnenberg et al. [1008] describe a process for electroplating a nonconducting substrate via formation of a film of a CP followed by electrodeposition of a metal. The CP film is deposited from an aqueous suspension of the CP containing an additional polymeric stabilizer. Other patents have related to printed circuit board applications [1011]. 

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