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High Reliability Metallurgical Structure for Multilevel Substrate Wiring

IP.com Disclosure Number: IPCOM000049121D
Original Publication Date: 1982-May-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 39K

Publishing Venue

IBM

Related People

Archey, WB: AUTHOR [+3]

Abstract

One conventional technique for providing multiple layers of metallization on a packaging substrate is to utilize a ceramic base on which a first level of metallization is applied, over which first level a layer of polyimide is applied, followed by a second level of metallization on top of the polyimide. An improved second level of metallization is provided by this technique.

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High Reliability Metallurgical Structure for Multilevel Substrate Wiring

One conventional technique for providing multiple layers of metallization on a packaging substrate is to utilize a ceramic base on which a first level of metallization is applied, over which first level a layer of polyimide is applied, followed by a second level of metallization on top of the polyimide. An improved second level of metallization is provided by this technique.

Referring now to the figure, which is a sectional view of a portion of a substrate, a ceramic base is provided. On the ceramic base is applied a layer of Cr, a layer of Cu and another layer of Cr in the thicknesses indicated. This Cr- Cu-Cr constitutes the first level of metallization. Over the top layer of Cr is provided a layer of polyimide.

On top of the polyimide is applied a layer of co-deposited 96% Al 4% Cu, over which is applied a layer of Cr, followed by a layer of Cu in the thicknesses indicated. Vias, one of which is shown, are provided through the polyimide to allow contact at the Al-Cu layer with the first level of metallization. This structure provides increased reliability of the contact between the two layers of metallization without loss of current carrying capacity when the metal thicknesses are properly chosen.

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