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Autocatalytic Electroless Lead

IP.com Disclosure Number: IPCOM000077122D
Original Publication Date: 1972-Jun-01
Included in the Prior Art Database: 2005-Feb-24
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Ameen, TJ: AUTHOR [+3]

Abstract

Described is a method to deposit thick films of lead on circuitry where no common electrical connection exists. A method is also described to catalyze lead deposition on copper.

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Autocatalytic Electroless Lead

Described is a method to deposit thick films of lead on circuitry where no common electrical connection exists. A method is also described to catalyze lead deposition on copper.

An electroless lead depositing bath is provided. The bath is comprised of: A lead salt, e.g., lead acetate (Pb(AC)(2) 3H(2)O) 0.025M A complexing agent to complex the Pb++ , E.G., EDTA/-4/ 0.05M A reducing agent capable of generating enough voltage to plate out the lead, e.g., dimethylamine borane ((CH(2))(2)NHBH(3)) 30 g/1 An alkaline medium, which is the most compatible with the reducing agent, e.g., pH 13.0 Temperature 180 degrees F.

This bath can produce thick deposits with plating rates up to 150 microinches per hour. The bath is quite stable and adaptable to continuous use.

Autocatalytic lead plating on copper can be accomplished by treating the surface of the copper to produce copper oxide and/or suitable copper salts. The lead plating can thus be initiated on the copper oxide; and can continuously proceed to the desired thickness by maintaining in the plating solution.

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