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Electrodeposition of Ductile Palladium

IP.com Disclosure Number: IPCOM000082449D
Original Publication Date: 1974-Dec-01
Included in the Prior Art Database: 2005-Feb-28
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Caricchio, JJ: AUTHOR [+3]

Abstract

Low-energy circuit contacts must be of low and stable contact resistance. Originally, gold was widely used for such circuit contacts in view of its excellent properties. Recently, palladium has increasingly been used to replace gold in forming low-energy circuit contacts on base metal substrates.

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Electrodeposition of Ductile Palladium

Low-energy circuit contacts must be of low and stable contact resistance. Originally, gold was widely used for such circuit contacts in view of its excellent properties. Recently, palladium has increasingly been used to replace gold in forming low-energy circuit contacts on base metal substrates.

In electrodepositing palladium on a base metal substrate for electrical contact use, two interrelated properties are required. Firstly, the palladium must be nonporous to prevent foreign matter from entering the electrodeposited palladium film and spreading onto the contact surface, where corrosion and like problems could arise. Secondly, the electrodeposited palladium layer must be ductile. Following previous processes for electrodepositing palladium, stressed electroplates resulted which tended to crack and eventually cause the electrodeposited film of palladium to become porous, leading to device failure.

The above-mentioned disadvantages are overcome by electrodepositing palladium from a high chloride aqueous electrodeposition bath, which contains NH(4)Cl, Pd(NH(3))(2)Cl(2) (palladosammine chloride) and aqueous NH(3) (ammonia)

The electrodeposition bath generally contains NH(4)Cl in an amount of from about 65 to about 250 g/l, more preferably from about 130 to about 250 g/l, with aqueous ammonia being present in an amount sufficient to provide a pH of at least about 8.8 to the bath. Most preferably the pH is maintained within th...