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Chemically Plating a Dielectric Base

IP.com Disclosure Number: IPCOM000098029D
Original Publication Date: 1961-Dec-01
Included in the Prior Art Database: 2005-Mar-07
Document File: 1 page(s) / 12K

Publishing Venue

IBM

Related People

Radovsky, DA: AUTHOR

Abstract

Chemical reduction baths and electroless plating methods are unstable and require frequent rejuvenation or replacement of the bath. This is because ordinarily the reducing agents for the metal salts are present in the bath and act for chemical reduction continuously during the life of the bath, extending over both used and unused time. In this method, the reducing agent is applied to the parts to be plated and thus is kept out of the bath except when in use.

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Chemically Plating a Dielectric Base

Chemical reduction baths and electroless plating methods are unstable and require frequent rejuvenation or replacement of the bath. This is because ordinarily the reducing agents for the metal salts are present in the bath and act for chemical reduction continuously during the life of the bath, extending over both used and unused time. In this method, the reducing agent is applied to the parts to be plated and thus is kept out of the bath except when in use.

The method involves first coating a dielectric material with a catalytic agent such as palladium and then treating the board with hydrogen gas. Finely divided palladium absorbs about 800 times its volume of hydrogen. Next, the coated board is placed in a reducible bath of metal salts (a bath without a reducing agent) to obtain a deposit of reduced metal over the palladium coating. The hydrogen, which by its adsorption into the palladium is now in a particularly active state. It acts as a reducing agent which is brought to the bath temporarily instead of being an agent which is in it constantly.

With the reducing agent on the dielectric material itself, the plating bath has indefinite life. Since the reducing agent is not a part of the plating bath, the bath is activated, i.e., the reduction of the metal will take place, only as long as the palladium-hydrogen coated board is immersed in the bath.

One way of performing the initial step for putting the palladium on the dielec...