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Interface Passivation Structure for Replaceable Chip Connection

IP.com Disclosure Number: IPCOM000050925D
Original Publication Date: 1982-Dec-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Ames, I: AUTHOR [+2]

Abstract

Separating and passivating interface metallurgy from the edge of an insulator layer eliminates an attack path by which contact mercury tends to short circuit an underlying metal layer in a microelectronic circuit. In certain microelectronic circuits, such as Josephson circuits, mercury can be used as a chip contact material. Mercury, however, is corrosive to superconducting metals such as lead and niobium. To prevent the mercury from attacking an underlying metal layer, an interface metallurgy structure is often used. In structures such as that shown in Fig. 1, an attack path indicated by the heavy arrow can exist along the interface between SiO layer 12 and interface layer 13 to metal layer 14. Mercury from Hg mass 15 finds its way to metal layer 14.

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Interface Passivation Structure for Replaceable Chip Connection

Separating and passivating interface metallurgy from the edge of an insulator layer eliminates an attack path by which contact mercury tends to short circuit an underlying metal layer in a microelectronic circuit. In certain microelectronic circuits, such as Josephson circuits, mercury can be used as a chip contact material. Mercury, however, is corrosive to superconducting metals such as lead and niobium. To prevent the mercury from attacking an underlying metal layer, an interface metallurgy structure is often used. In structures such as that shown in Fig. 1, an attack path indicated by the heavy arrow can exist along the interface between SiO layer 12 and interface layer 13 to metal layer 14. Mercury from Hg mass 15 finds its way to metal layer 14.

An alternate interface passivation structure is shown in Fig. 2, which eliminates such attack by mercury and also eliminates problems which might be associated with the marginal nature of the interface metallurgy at the edges of the SiO layer. In this structure, the interface metallurgy (IFM) 23 overlies the metal layer 24 and does not contact the SiO layer 22. A passivation layer 25 of parylene overlies SiO layer 22 and is present in the space between IFM 23 and SiO layer 22. The mercury (Hg) 25 is therefore not at the SiO-metal interface and the attack path of Fig. 1 is eliminated. Since the parylene has conformal properties, it protects the SiO-metal...