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Cleaning Sintered Multilayer Ceramic Pad Surfaces for Plating

IP.com Disclosure Number: IPCOM000088030D
Original Publication Date: 1977-Apr-01
Included in the Prior Art Database: 2005-Mar-04
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Harvilchuck, JM: AUTHOR [+3]

Abstract

The top and bottom surfaces of fired multilayered ceramic modules, ordinarily carry a number of pads, which, after nickel plating, are joined with integrated-circuit chips and input/output pins by soldering or brazing. The pads consist of molybdenum and alumina particles and of certain silicates which have been sintered together in the firing step of the multilayer ceramic module. Before nickel plating, the alumina, the silicates and molybdenum oxides which have been formed in the firing cycle must be cleaned from the surfaces of the pads. In the firing cycle, MoO(3), which is warm soluble in an alkaline solution, Mo(2)O(5), which is soluble in warm acids only, and MoO(2) which is soluble in concentrated nitric acid, form and must be removed.

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Cleaning Sintered Multilayer Ceramic Pad Surfaces for Plating

The top and bottom surfaces of fired multilayered ceramic modules, ordinarily carry a number of pads, which, after nickel plating, are joined with integrated-circuit chips and input/output pins by soldering or brazing. The pads consist of molybdenum and alumina particles and of certain silicates which have been sintered together in the firing step of the multilayer ceramic module. Before nickel plating, the alumina, the silicates and molybdenum oxides which have been formed in the firing cycle must be cleaned from the surfaces of the pads. In the firing cycle, MoO(3), which is warm soluble in an alkaline solution, Mo(2)O(5), which is soluble in warm acids only, and MoO(2) which is soluble in concentrated nitric acid, form and must be removed.

In this process the fired multilayer ceramic modules are dipped in a KOH- ferricyanide solution, rinsed in water, and subsequently dipped at room temperature for about five to ten minutes in the water solution of 50 grams per liter sodium hydroxide and 50 grams per liter hydrogen peroxide. After a water rinse, the modules are ready for the usual palladium activation and electroless nickel plating steps.

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