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Protection Against Corrosion of Molybdenum Metallurgy in Multilayer Ceramic Modules

IP.com Disclosure Number: IPCOM000087738D
Original Publication Date: 1977-Mar-01
Included in the Prior Art Database: 2005-Mar-03
Document File: 1 page(s) / 11K

Publishing Venue

IBM

Related People

Brunsch, A: AUTHOR [+2]

Abstract

A high-density sintered molybdenum is utilized for internal circuit patterns and for the top and bottom side metallurgy of multilayer ceramic modules, since, during the sintering process, this metallurgy shows almost the same shrinking properties as the substrate materials of alumina ceramic. However, the molybdenum is highly susceptible to reactive corrosion when exposed to humidity of any pH value at operating potentials common in multilayer ceramic module applications. This corrosion interrupts conductors and leads to module failure.

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Protection Against Corrosion of Molybdenum Metallurgy in Multilayer Ceramic Modules

A high-density sintered molybdenum is utilized for internal circuit patterns and for the top and bottom side metallurgy of multilayer ceramic modules, since, during the sintering process, this metallurgy shows almost the same shrinking properties as the substrate materials of alumina ceramic. However, the molybdenum is highly susceptible to reactive corrosion when exposed to humidity of any pH value at operating potentials common in multilayer ceramic module applications. This corrosion interrupts conductors and leads to module failure.

One way to overcome the molybdenum corrosion problem is to protect the molybdenum metallurgy during the sintering operation by forming a corrosion- resistant nickel-molybdenum layer.

With this method a nickel paste is screened on the top of the molybdenum metallurgy prior to the sintering operation. The nickel, which is liquid at the sintering temperatures, forms an alloy with the molybdenum, and, when cooling the liquid alloy, generates a closed nonporous layer, preventing humidity from entering the sintered molybdenum metallurgy. The method can also be applied to tungsten metallurgy. This process eliminates wet plating processes, and prevents moisture residue at the interface between the molybdenum and the protective plated film, and in the spongy molybdenum.

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