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Adhesion-Enhancement Layer for MCP M-2 Metallurgy

IP.com Disclosure Number: IPCOM000042556D
Original Publication Date: 1984-May-01
Included in the Prior Art Database: 2005-Feb-04
Document File: 2 page(s) / 34K

Publishing Venue

IBM

Related People

Feather, BA: AUTHOR [+4]

Abstract

In the making of a multilayer integrated circuit substrate, there has evolved a metallized ceramic polyimide (MCP) structure. This structure comprises a ceramic substrate on which is evaporated a first layer M-1 of chrome-copper-chrome on which printed circuitry is formed on the copper, a layer of polyimide, and a second evaporated layer M-2 of chrome-copper-chrome on which printed circuitry is formed on the copper. Via holes are formed in the polyimide, prior to the deposition of the M-2 layer, which extend down to the copper circuitry of the M-1 layer and which conductively connect the circuitry on the M-1 and M-2 layers.

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Adhesion-Enhancement Layer for MCP M-2 Metallurgy

In the making of a multilayer integrated circuit substrate, there has evolved a metallized ceramic polyimide (MCP) structure. This structure comprises a ceramic substrate on which is evaporated a first layer M-1 of chrome-copper- chrome on which printed circuitry is formed on the copper, a layer of polyimide, and a second evaporated layer M-2 of chrome-copper-chrome on which printed circuitry is formed on the copper. Via holes are formed in the polyimide, prior to the deposition of the M-2 layer, which extend down to the copper circuitry of the M-1 layer and which conductively connect the circuitry on the M-1 and M-2 layers. It is proposed that preceding the copper deposition, the evaporation of an extremely thin layer of chrome will provide the necessary adhesion for process survival and will allow excellent via hole reliability for long term machine and field life. A thin layer of chrome will be uniform over the polyimide, thereby improving adhesion, while at the bottom of the via hole the layer will be highly discontinuous because of the extreme roughness of the M-1 metallurgy. Thus, the copper deposited thereafter will essentially be "blind" to the chrome present in the via and will be able to bond to the copper of the M-1 metallurgy to provide reliable vias. Chrome-copper-chrome layers, where the bottom chrome thicknesses were 10 ~, 25 ~, 50 ~ and 100 ~ were evaporated onto MCP substrates at the standard M-2...